appendix f design and operations report · 2020. 5. 15. · 3.1 service area ... 15.5 ridge...

April 2020 18111331 (4000-1)

APPENDIX F

Design and Operations Report

Ridge Landfill Expansion: Design and Operations Report Appendix D6

Submitted to:

Ridge (Chatham) Holdings G.P. Inc./ Waste Connections of Canada Inc. 20262 Erieau Road P.O. Box 1871 Blenheim, Ontario N0P 1A0

Submitted by:

Golder Associates Ltd. 6925 Century Avenue, Suite #100, Mississauga, Ontario, L5N 7K2, Canada

+1 905 567 4444

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Distribution List 1 copy

1 e-copy

1 copy

1 copy

1 copy

2 copies

1 e-copy

1 e-copy

1 e-copy

MECP, Client Services and Permissions Branch

MECP, Client Services and Permissions Branch

MECP, Windsor Area District Office

MECP, Sarnia District Office

Municipality of Chatham-Kent

Waste Connections of Canada

Waste Connections of Canada

Dillon Consulting

Golder Associates Ltd.

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Table of Contents

1.0 INTRODUCTION ............................................................................................................................................. 1

1.1 Purpose and Scope .............................................................................................................................. 1

1.2 Regulatory Requirements .................................................................................................................... 1

1.2.1 Environmental Protection Act (EPA) ............................................................................................... 2

1.2.2 Ontario Regulation 232/98 – Landfill Sites ..................................................................................... 2

1.2.3 Ontario Water Resources Act (OWRA) .......................................................................................... 2

1.3 Description of the Undertaking ............................................................................................................. 2

2.0 SITE DESCRIPTION ....................................................................................................................................... 3

2.1 Site Location......................................................................................................................................... 3

2.2 Existing and Proposed Site Boundaries ............................................................................................... 3

2.3 Existing and Proposed Land Use ......................................................................................................... 3

2.3.1 Conservation Areas ........................................................................................................................ 4

2.4 Topography and Drainage ................................................................................................................... 4

2.5 Geology/Hydrogeology ......................................................................................................................... 4

3.0 WASTE QUANTITIES AND CHARACTERISTICS ........................................................................................ 5

3.1 Service Area ......................................................................................................................................... 5

3.2 Waste Quantities .................................................................................................................................. 5

3.3 Waste Characteristics .......................................................................................................................... 5

4.0 PROPOSED EXPANDED FILL AREA DESIGN ............................................................................................ 5

4.1 Design Approach .................................................................................................................................. 5

4.2 Design Criteria...................................................................................................................................... 6

4.3 Limits of Landfilling ............................................................................................................................... 6

4.4 Base Contours...................................................................................................................................... 7

4.4.1 Proposed Old Landfill Base Contours ............................................................................................. 7

4.4.2 Proposed Area A and Area B Base Contours ................................................................................. 7

4.5 Final Contours ...................................................................................................................................... 8

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4.6 Landfill Capacity Calculations .............................................................................................................. 9

4.7 Soil Balance ......................................................................................................................................... 9

5.0 SITE FEATURES ............................................................................................................................................ 9

5.1 Site Entrances .................................................................................................................................... 10

5.2 On-Site Roads .................................................................................................................................... 10

5.3 Weigh Scale and Scale House ........................................................................................................... 11

5.4 Administration and Maintenance Buildings ........................................................................................ 11

5.5 Existing/Future Leachate Management Area ..................................................................................... 11

5.6 Existing/Future Landfill Gas Management Area ................................................................................ 11

5.7 Stormwater Management Ponds........................................................................................................ 11

5.8 Flood Control Facility ......................................................................................................................... 12

5.9 Municipal Drains ................................................................................................................................. 13

5.9.1 Howard Drain ................................................................................................................................ 13

5.9.2 Duke Drain .................................................................................................................................... 13

5.9.3 Lewis Drain ................................................................................................................................... 14

5.9.4 Summary of Municipal Drain Modifications ................................................................................... 14

5.10 Stockpiles ........................................................................................................................................... 14

5.11 Screening Berms ................................................................................................................................ 14

5.12 Woodlots ............................................................................................................................................ 15

5.13 Public Waste Drop-Off and Processing Facilities .............................................................................. 15

5.13.1 Public Waste Drop-Off Area .......................................................................................................... 15

5.13.2 Future Public Recycling Area ........................................................................................................ 15

5.13.3 Beneficial Use Materials Laydown Area ....................................................................................... 16

6.0 SURFACE WATER MANAGEMENT PLAN ................................................................................................. 16

6.1 Drainage Design Goals and Objectives ............................................................................................. 16

6.1.1 Water Quality ................................................................................................................................ 16

6.1.2 Water Quantity and Erosion Control ............................................................................................. 17

6.2 Surface Water Plan Components....................................................................................................... 17

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6.2.1 Water Quality ................................................................................................................................ 17

6.2.1.1 Separation of Leachate from Surface Water Drainage System................................................. 17

6.2.1.2 Restricted Use of Fertilizers, Pesticides, Herbicides and Road Salt ......................................... 17

6.2.1.3 Dust Control Plan ....................................................................................................................... 18

6.2.1.4 Site Grading ............................................................................................................................... 18

6.2.1.5 Buffer Zone ................................................................................................................................ 18

6.2.1.6 Stormwater Ponds ..................................................................................................................... 18

6.2.2 Water Quantity and Erosion Control ............................................................................................. 19

6.2.2.1 Internal Conveyance System ..................................................................................................... 19

6.2.2.2 Stormwater Ponds ..................................................................................................................... 19

6.2.2.3 Flood Control Berm .................................................................................................................... 20

6.2.2.4 Municipal Drain Modifications .................................................................................................... 20

6.2.2.5 Flood Control Facility ................................................................................................................. 20

6.2.2.6 Surface Water Diversion Berms ................................................................................................ 20

7.0 LEACHATE MANAGEMENT SYSTEM ........................................................................................................ 20

7.1 Leachate Management Objectives..................................................................................................... 20

7.2 Leachate Management Philosophy .................................................................................................... 21

7.3 Leachate Characterization ................................................................................................................. 21

7.4 Final Cover Design ............................................................................................................................. 22

7.5 Leachate Generation .......................................................................................................................... 22

7.6 Leachate Control System Design Approach and Rationale ............................................................... 23

7.7 Leachate Control System Design for the Expansion of the Old Landfill Area ................................... 24

7.7.1 Existing Leachate Collection System ............................................................................................ 24

7.7.2 Expansion Design Approach ......................................................................................................... 24

7.7.3 Proposed Leachate Collection System Expansion ....................................................................... 24

7.7.4 Proposed East Infill Base .............................................................................................................. 25

7.7.5 Proposed Perimeter Drain and Finger Drain Design .................................................................... 25

7.7.5.1 Design Peer Review .................................................................................................................. 26

7.7.6 Temporary Interior Slope Berms ................................................................................................... 26

7.7.7 Seepage Diversion Berm .............................................................................................................. 27

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7.7.8 Lateral Control Measures .............................................................................................................. 27

7.8 Leachate Control System Design for Expansion of the West and South Landfills (Areas A and B) ........................................................................................................................................................ 27

7.8.1 Lateral Control Measures .............................................................................................................. 30

7.8.2 Future Toe Drain ........................................................................................................................... 30

7.9 Leachate Storage Tank and Transfer Pump Capacity Review .......................................................... 30

7.10 Off-Site Leachate Municipal Forcemain Review ................................................................................ 31

7.11 Leachate Recirculation Option ........................................................................................................... 31

7.12 Leachate Treatment/Disposal ............................................................................................................ 31

7.12.1 Off-Site Capacity and Treatability Assessment ............................................................................ 31

8.0 LANDFILL GAS MANAGEMENT SYSTEM ................................................................................................. 32

8.1 Gas Management Objectives ............................................................................................................. 32

8.2 LFG Generation Rates for the Entire Landfill ..................................................................................... 32

8.3 LFG Collection Rates for the Entire Landfill ....................................................................................... 34

8.4 LFG Assessment for the Existing Waste of the Old Landfill .............................................................. 35

8.5 Gas Collection System ....................................................................................................................... 36

8.5.1 Existing LFGCS............................................................................................................................. 36

8.5.2 LFGCS Philosophy for the Proposed Expansion .......................................................................... 37

8.5.3 Vertical Gas Extraction Wells ........................................................................................................ 37

8.5.4 LFG Headers, Sub-headers and Laterals ..................................................................................... 38

8.5.5 Condensate Management ............................................................................................................. 38

8.6 Gas Combustion ................................................................................................................................ 38

8.7 Remedial Action for Landfill Gas Control ........................................................................................... 39

9.0 LFG SUBSURFACE MIGRATION ................................................................................................................ 39

10.0 COMPLIANCE WITH THE ENGINEERED FACILITIES GUIDELINE AND LANDFILL STANDARDS ...... 40

10.1 Landfill Final Cover ............................................................................................................................ 41

10.2 Leachate Collection System ............................................................................................................... 42

10.3 Pumping Facilities and Leachate Storage Tanks............................................................................... 42

10.4 Perimeter Cut-Off Wall ....................................................................................................................... 43

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10.5 Recompacted Clay Side Slope Liner ................................................................................................. 43

10.6 Toe Drains .......................................................................................................................................... 43

10.7 Landfill Gas Collection and Management Facilities ........................................................................... 44

10.8 Surface Water Management Facilities ............................................................................................... 44

11.0 CLIMATE CHANGE CONSIDERATIONS .................................................................................................... 44

11.1 Greenhouse Gas Mitigation ............................................................................................................... 45

11.2 Climate Change Adaptation ............................................................................................................... 45

12.0 LANDFILL DEVELOPMENT ........................................................................................................................ 46

12.1 Landfill Expansion Phasing Plan ........................................................................................................ 46

13.0 LANDFILL OPERATIONS ............................................................................................................................ 48

13.1 Hours of Operation ............................................................................................................................. 48

13.2 Site Equipment ................................................................................................................................... 48

13.3 Landfill Staff........................................................................................................................................ 49

13.3.1 Training Program .......................................................................................................................... 50

13.4 Landfilling Operations ........................................................................................................................ 50

13.4.1 Normal Waste Landfilling Operations ........................................................................................... 50

13.4.2 Daily, Intermediate and Final Cover Placement ........................................................................... 51

13.4.3 Initial Lift Landfilling Operations .................................................................................................... 52

13.5 Surface Water Management .............................................................................................................. 52

13.6 Leachate Management ...................................................................................................................... 53

13.7 Landfill Gas Management .................................................................................................................. 54

13.7.1 Operation and Maintenance .......................................................................................................... 54

14.0 SITE CONTROL AND MAINTENANCE ....................................................................................................... 55

14.1 Access and On-Site Traffic Control .................................................................................................... 55

14.2 Waste Control..................................................................................................................................... 56

14.3 Litter Control ....................................................................................................................................... 57

14.4 Odour Control ..................................................................................................................................... 58

14.5 Dust Control ....................................................................................................................................... 59

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14.6 Bird and Non-Bird Vector Control....................................................................................................... 60

14.7 Fire Control ......................................................................................................................................... 60

14.7.1 General ......................................................................................................................................... 60

14.7.2 Landfill Fires and Explosions ........................................................................................................ 61

14.8 Site Inspection and Maintenance ....................................................................................................... 62

14.8.1 Inspection ...................................................................................................................................... 62

14.8.2 Routine Maintenance .................................................................................................................... 65

15.0 MONITORING AND REPORTING ................................................................................................................ 65

15.1 Operation and Development Monitoring ............................................................................................ 65

15.1.1 Development Monitoring ............................................................................................................... 66

15.1.2 Site Inspections ............................................................................................................................. 66

15.1.3 Incoming Waste Records .............................................................................................................. 67

15.2 Environmental Monitoring .................................................................................................................. 68

15.2.1 Groundwater Monitoring ............................................................................................................... 68

15.2.2 Surface Water Monitoring ............................................................................................................. 70

15.2.2.1 Surface Water Assessment .......................................................................................................... 71

15.2.2.2 Stormwater Ponds Discharge Objectives ..................................................................................... 71

15.2.3 Leachate Collection System Monitoring ....................................................................................... 71

15.2.4 Old Landfill Leachate Level Monitoring ......................................................................................... 72

15.2.5 Landfill Gas Monitoring ................................................................................................................. 72

15.2.6 Private Groundwater Well Monitoring ........................................................................................... 73

15.2.7 Air Monitoring ................................................................................................................................ 73

15.3 Complaint Response Procedure ........................................................................................................ 74

15.4 Annual Reports................................................................................................................................... 74

15.5 Ridge Landfill Liaison Committee....................................................................................................... 75

16.0 SITE CLOSURE ............................................................................................................................................ 76

16.1 Site Closure Works ............................................................................................................................ 77

16.2 Post-Closure Care .............................................................................................................................. 77

16.3 End Use .............................................................................................................................................. 78

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17.0 CONTINGENCY PLANS ............................................................................................................................... 78

17.1 Groundwater Contingency Plan ......................................................................................................... 78

17.1.1 Tier 1 - Investigation ..................................................................................................................... 78

17.1.2 Tier 2 – Design, Approval and Implementation ............................................................................. 79

17.2 Surface Water Contingency Plans ..................................................................................................... 79

17.3 Old Landfill Leachate Seep Trigger Mechanism and Contingency Plan ........................................... 80

17.3.1 Peer Review .................................................................................................................................. 81

17.4 Old Landfill Leachate Mound Trigger Mechanism and Contingency Plan ......................................... 81

17.5 Other Contingencies .......................................................................................................................... 81

17.5.1 Temporary Leachate Management ............................................................................................... 81

17.5.2 Landfill Gas ................................................................................................................................... 82

17.5.3 Archaeology and Heritage Resources .......................................................................................... 82

17.5.4 Transportation ............................................................................................................................... 82

18.0 DEFINITIONS ................................................................................................................................................ 82

TABLES

Table 4.1: Soil Balance ............................................................................................................................................. 9

Table 6.1: Minimum Volume Requirements for Stormwater Ponds ....................................................................... 19

Table 12.1: Estimated Construction and Operation Timeline ................................................................................. 46

Table 15.1: Summary of Groundwater Monitoring Program – Old Landfill ............................................................ 68

Table 15.2: Summary of Groundwater Monitoring Program – West Landfill/Area A and South Landfill/Area B .... 68

Table 15.3: List of Groundwater Parameters ......................................................................................................... 69

Table 15.4: Surface Water Monitoring Target Parameter List ................................................................................ 71

Table 15.5: Leachate Collection System Monitoring Program ............................................................................... 72

Figure 8.1: Landfill Gas Generation Results for the Entire Landfill ........................................................................ 34

Figure 8.2: Landfill Gas Generation Results for the Existing Waste of the Old Landfill ......................................... 35

FIGURES

Figure 8.1: Landfill Gas Generation Results for the Entire Landfill ........................................................................ 34

Figure 8.2: Landfill Gas Generation Results for the Existing Waste of the Old Landfill ......................................... 35

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REFERENCES

DRAWINGS

Drawings 1 to 29

SUB-APPENDICES Sub-Appendix D6-A – Geotechnical Assessment Technical Memorandum

Sub-Appendix D6-B – Ridge Landfill HELP Model

Sub-Appendix D6-C – Calculation of Mounding Between Finger Drains

Sub-Appendix D6-D – Design Peer Review Memorandum

Sub-Appendix D6-E – Leachate Collection System Pipe Structural Stability Calculations

Sub-Appendix D6-F – Approval Documentation for the Site-Specific Leachate Collection System Design

Sub-Appendix D6-G – Ridge Landfill On-Site Leachate Infrastructure Memo

Sub-Appendix D6-H – Ridge Off-Site Leachate Infrastructure Memo

Sub-Appendix D6-I – LFG Estimates – Do-Nothing Condition

Sub-Appendix D6-J – LFG Estimates – Expansion Condition

Sub-Appendix D6-K – Finger Drain Service Life Calculation

Sub-Appendix D6-L – Peer Review Memorandum #2

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1.0 INTRODUCTION 1.1 Purpose and Scope This document is the Design and Operations (D&O) Report for the proposed expansion of the Ridge Landfill, located near Blenheim, Ontario. This D&O Report supports an application for approval under the Environmental Assessment Act (EAA). The D&O Report is also intended, with possible modifications and/or addenda, to satisfy requirements that may arise from the EAA review and approvals process, for use in support of subsequent applications for Environmental Compliance Approvals (ECAs) under the Environmental Protection Act (EPA) and Ontario Water Resources Act (OWRA) for the Ridge Landfill expansion.

The Ridge Landfill is a Municipal Solid Waste (MSW) facility owned and operated by Ridge (Chatham) Holdings L.P., a wholly owned subsidiary of Waste Connections of Canada Inc. (Waste Connections). The Ridge Landfillreceived a Ministry of the Environment, Conservation and Parks (MECP) consolidated Waste Certificate of Approval (ECA) on May 1, 2013, under the Number A021601. This ECA consolidated and revoked the previous ECA and subsequent amendments.

The D&O components specifically described in this document include the following:

Regulatory and approval requirements;

Site development boundaries, zoning and surrounding land uses;

Details about the characteristics and quantities of waste to be accepted at the Landfill;

Grading plans and proposed final landfill geometry;

Surface water management;

Leachate management;

Landfill gas (LFG) and odour management;

Landfill development phasing;

Landfill operations, inspection and maintenance;

Monitoring programs;

Landfill closure and post-closure maintenance; and

Contingency measures.

All D&O components described in this report have been prepared to meet the regulatory requirements described in Ontario Regulation (O. Reg.) 232/98 (MOE, 1998) and the associated guidance document “Landfill Standards: A Guideline on the Regulatory and Approval Requirements for New or Expanding Landfilling Sites” (MOE, 2012).

1.2 Regulatory Requirements The proposed expansion requires approval under the Environmental Assessment Act (EAA), and also subsequent Environmental Compliance Approvals (ECAs) under the Environmental Protection Act (EPA) and Ontario Water Resources Act (OWRA).

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1.2.1 Environmental Protection Act (EPA) Waste disposal sites are subject to Part V of the EPA. Section 27 of the EPA requires that an ECA be obtained from the Director of the MECP for the establishment, operation, alterations, or enlargement of a waste disposal site or for waste diversion, processing and transfer facilities.

Legislative framework for waste management is provided in Part V of the EPA Regulatory Requirements for the design and operation of a landfill, as detailed in Ontario Regulation (O. Reg.) 347 (MOE, 1990) and O. Reg. 232/98 (MOE, 1998). O. Reg. 347 provides a definition of waste management terms and classes and provides standards for design and operation of landfills less than or equal to 40,000 cubic metres (m3) in volume. O. Reg. 232/98 provides standards for design and operation of landfill sites greater than 40,000 m3 in volume. As the landfill component of the Ridge Landfill expansion is greater than 40,000 m3 in volume, the design and operation of the landfill are subject to O. Reg. 232/98.

The definition of “municipal waste”, as described in O.Reg. 347 is “any waste, whether or not it is owned, controlled or managed by a municipality, except, (i) hazardous waste, (ii) liquid industrial waste, or (iii) gaseous waste”. Therefore, the following regulations that refer to municipal waste also apply to the Ridge Landfill expansion.

1.2.2 Ontario Regulation 232/98 – Landfill Sites O. Reg. 232/98 (MOE, 1998) contains detailed requirements for the design, operation, closure and post-closure care of municipal waste landfills (as defined in Section 1.2.1). The document entitled Landfill Standards, A Guideline on the Regulatory and Approval Requirements for New or Expanding Landfill Sites (MOE, 2012) provides guidance to the application of the Regulation.

1.2.3 Ontario Water Resources Act (OWRA) The purpose of the OWRA is for the protection and conservation of surface water and groundwater resources in the Province of Ontario. Any system that discharges to a surface water body requires approval under the OWRA. The Ridge Landfill expansion requires OWRA approval (Section 53 – Sewage Works) for the discharge of surface water from the Ridge Landfill to several municipal drains, including the Duke Drain, Howard Drain, Lewis Drain and Scott Drain.

1.3 Description of the Undertaking Waste Connections is proposing an expansion of the Ridge Landfill to continue to provide long-term MSW disposal capacity. The Ridge Landfill is an important component of the waste management services provided by Waste Connections and is a prominent business within the local community.

The Ridge Landfill is approved for a total fill volume (MSW plus daily cover soils) of 21 million cubic metres (m3) excluding the capacity of the existing Old Landfill. The Ridge Landfill is approved to accept a maximum of 1,300,000 tonnes of MSW per year. As of May 2018, it is estimated that the existing approved waste fill area at the Ridge Landfill Site will provide waste disposal capacity until March 2021 at the current fill rate.

The waste being landfilled is approximately 98% IC&I waste and 2% residential waste. As part of the EA approval, Waste Connections propose to reduce their IC&I service area from all of Ontario to just southern and central Ontario, and their residential service area from Chatham-Kent and the neighbouring counties of Essex, Lambton, Middlesex and Elgin, to only the Municipality of Chatham-Kent.

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Waste Connections is seeking an EA approval to increase the Ridge Landfill capacity by 28.9 million m3 over a 20-year planning period, i.e., from 2021 to 2041. The EA does not propose to increase the maximum annual fill rate of 1,300,000 tonnes per year.

2.0 SITE DESCRIPTION 2.1 Site Location The location of the Ridge Landfill is shown on the attached Drawing 1 (Cover Sheet/Location Plan).

The Ridge Landfill is located in the Municipality of Chatham-Kent at 20262 Erieau Road (Concession Road 4), approximately 5 km southwest of Blenheim, Ontario. The legal description is the Township of Harwich, parts of Lots 13 to 16 of Concession 4, Municipality of Chatham-Kent. The Ridge Landfill is north of Allison Line, between Erieau Road to the east and Charing Cross Road (County Road 10) to the west.

2.2 Existing and Proposed Site Boundaries For the purposes of this report, the key areas and boundaries are defined as follows:

Ridge Landfill Property is the entire land located west of Erieau Road within the property limit shown on Drawing 2. This property is owned by Waste Connections and has an area of approximately 340 hectares (ha).

Site is the area within the Ridge Landfill property that is approved by the ECA, which includes the waste disposal areas, the associated environmental works, and the facilities required for the ancillary waste management activities. The approved Site boundary is shown on Drawings 2 and 3 and has an area of 262 ha.

Approved Waste Fill Area is the approved waste disposal area that encompasses the 131 ha area that is presently approved by the ECA for the disposal of waste and is comprised of the Old Landfill (55.2 ha), West Landfill (55.3 ha) and South Landfill (20.3 ha). The Approved Waste Fill Area is the area within the approved waste limits shown on Drawing 3.

Proposed Waste Fill Area encompasses the Approved Waste Fill Area and the expansion Waste Fill Area to accommodate the proposed expansion. The Proposed Waste Fill Area is the area within the approved waste fill limit and proposed waste fill limit shown on Drawing 4. The waste fill area is proposed to increase by approximately 55 ha, i.e., from 131 ha to approximately 186 ha. The Old Landfill waste fill area (55.2 ha) will remain unchanged; the proposed Area A will add a waste fill area of 32.1 ha to the existing West Landfill (55.3 ha) for a combined waste fill area of 87.4 ha; the proposed Area B will add a waste fill area of 22.8 ha to the existing South Landfill (20.3 ha) for a combined waste fill area of 43.1 ha.

The definitions above are used throughout this report and are included in the Definitions section at the end of this Report.

2.3 Existing and Proposed Land Use The Ridge Landfill Property was formerly used for farming. Landfilling operations started within the Old Landfill area in the 1960s. The waste footprint progressively increased with the development and operation of the West Landfill starting in 2000 and the South Landfill starting in 2016.

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According to the Chatham-Kent Official Plan consolidated in November 19, 2018, the Ridge Landfill Property is designated as Waste Management Area, Conservation and Agriculture/Buffer Area. The Official Plan Schedule 4 shows the Ridge Landfill Property with three municipal zones: Waste Management Site, Open Space/Conservation Lands and Agricultural Buffer. The Comprehensive Zoning By-Law No. 216-2009 consolidated on April 24, 2019 permits the current landfill use. The proposed landfill expansion will require an amendment to the Zoning By-Law 216-2009 to extend the Site boundary. Waste Connections is currently seeking this Zoning By-Law amendment with the Municipality of Chatham-Kent.

2.3.1 Conservation Areas The majority of the Ridge Landfill Property was cleared of forest many years ago; however, there are three woodlots that remain. Drawings 2 and 3 show the location of the Northeast Woodlot, Southeast Woodlot and Southwest Woodlot. The Southwest Woodlot will be cleared and rezoned as landfill to allow the expansion of the West Landfill. The other two woodlots will remain.

2.4 Topography and Drainage The Site is situated at the southern portion of the Jeanette's Creek Subwatershed. The subwatershed, which encompasses an area of approximately 380 km2, is oriented in a southeast to northwest direction and outlets into the Thames River 3 km upstream of Lake St. Clair [Refer to Figure D10-4 of Appendix D10 - Surface Water Impact assessment of the Environmental Assessment Report for the proposed expansion].

Surface runoff originating from the Ridge Landfill is conveyed by several municipal drains including the Duke Drain, Howard Drain, Lewis Drain and Scott Drain (Drawing 2).

Local topography is considered flat to depressional and surface water generally flows from east to west and from south to north.

2.5 Geology/Hydrogeology The Landfill Site is situated on the St. Clair Clay Plain physiographic region as defined by Chapman and Putnam. The till plain consists of slightly stony, clayey silt Port Stanley Till. This unit is the predominant surficial unit, but localized, shallow deposits of lacustrine silts and clays do occur. Below the Ridge Landfill Property, the Port Stanley Till ranges in thickness from 38 metres to 44 metres. The upper portion of the till unit, assigned the designation of "Layer 1", generally exhibits weathering and vertical to sub-vertical fracturing. This weathered unit extends to depths ranging from 2 metres to 6.6 metres below ground surface. In addition to fractures, discontinuities were found in the upper till unit during test pit excavations and drilling. These discontinuities consist of primarily vertically oriented sand and silt bodies.

At depth, the Port Stanley Till becomes unfractured and unweathered. It is described as grey, dense to very dense clayey silt with trace sand and fine gravel. This lower portion of the till unit has been assigned the designation of "Layer 2".

The Port Stanley Till rests on a basal lacustrine sand/gravel unit, which is in turn underlain by bedrock. The bedrock at the Ridge Landfill Property is the Late Devonian shale of the Kettle Point Formation. Drilling indicates that this shale is highly weathered and fractured to a depth of approximately 3 metres. The sand/gravel unit and the Kettle Point shale have been grouped together and assigned the designation of "Layer 3".

The weathered Port Stanley Till unit is characterized hydrogeologically by predominantly horizontal groundwater flow directions that are influenced by surficial drainage features, surface topography and the surface topography of

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the underlying unweathered till unit. Horizontal groundwater fluxes in the weathered till unit are relatively high compared to the unweathered unit. The unweathered Port Stanley Till unit is characterized, and can be distinguished from the weathered unit, by a dominant, vertically downward, groundwater flow direction, a low groundwater flux, and hydraulic conductivities on the order of 1x10-8 cm/s.

The basal sand/gravel unit and fractured shale bedrock form the principal aquifer in the area of the Landfill Site and provide the principal pathway for regional groundwater movement. Horizontal groundwater movement is predominantly east to southeast and occurs under very low horizontal gradients (0.0005 m/m). Hydraulic conductivity testing yielded values on the order of 1x10-4 cm/s.

3.0 WASTE QUANTITIES AND CHARACTERISTICS 3.1 Service Area The Ridge Landfill is presently approved to receive solid, non-hazardous industrial, commercial, and institutional (IC&I) waste for disposal from all of Ontario, and residential waste from the Municipality of Chatham-Kent and the neighbouring Counties of Essex, Lambton, Middlesex, and Elgin. The waste being landfilled is approximately 98% IC&I waste and 2% residential waste. As part of the EA approval, Waste Connections propose to reduce their IC&I service area from all of Ontario to southern and central Ontario, and their residential service area from Chatham-Kent and the neighbouring counties of Essex, Lambton, Middlesex and Elgin, to only the Municipality of Chatham-Kent.

3.2 Waste Quantities An Environmental Screening process was undertaken in 2011 to increase the daily maximum fill rate from 4,391 tonnes per day to 6,661 tonnes per day, and the annual maximum fill rate from 899,000 tonnes per year to 1,300,000 tonnes per year, including approved alternative daily cover. An amendment to the Environmental Compliance Approval No. A021601 was issued on March 15, 2012, approving the increased daily maximum fill rate and the annual maximum fill rate.

No changes are proposed to the maximum daily and annual fill rate.

3.3 Waste Characteristics The waste currently accepted at the Ridge Landfill consists of up to approximately 1,300,000 tonnes per year of solid, non-hazardous waste generated mostly from the industrial, commercial, and institutional (IC&I) sector and a relatively small amount of residential waste. Liquid, hazardous, toxic, pathological, and radioactive wastes will be specifically prohibited.

4.0 PROPOSED EXPANDED FILL AREA DESIGN This section describes the layout, size, and shape of the proposed expanded waste fill areas and the rationale for the design.

4.1 Design Approach The conceptual design of the proposed expansion of the Ridge Landfill was developed in accordance with applicable MECP regulations, policies, and guidelines, including O. Reg. 232/98 (MOE, 1998).

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The Ridge Landfill consists of three distinct waste disposal areas: the Old Landfill, the West Landfill, and the South Landfill. The following expansion is proposed at each of these areas (see Drawing 4):

Old Landfill - The proposed expansion associated with the Old Landfill will comprise an approximately 30 m vertical expansion and a minor infill expansion to the east within the existing 55.2 ha approved waste fill area. The minor East Infill is proposed as a result of an optimization of the Old Landfill final contours and surface water drainage improvements and will have a waste fill area of 2.2 ha. See Drawing 4 for the location of the East Infill;

West Landfill – The West Landfill has an approved waste fill area of 55.3 ha. The proposed expansion of the West Landfill comprises a 32.1 ha lateral expansion to the south. This lateral expansion is referred to in this report as Area ‘A’. The West Landfill/Area A will have a combined waste fill area of 87.4 ha; and

South Landfill – the proposed expansion associated with the South Landfill includes both a vertical expansion of approximately 5 m over the existing South Landfill, as well as a 22.8 ha lateral expansion towards the south. This lateral expansion is referred to in this report as Area ‘B’. The South Landfill/Area B will have a combined waste fill area of 43.1 ha.

4.2 Design Criteria The following design criteria were used in the conceptual design of the proposed expansion:

1,300,000 tonnes per year of waste per year to be disposed of over a twenty-year expansion filling period;

Apparent waste density of 0.9 tonnes/m3 (i.e., 0.9 tonnes of compacted waste excluding cover soils per cubic metre of landfill air space);

Landfill expansion volumetric capacity of 28.9 million m3 for waste and daily cover (i.e., 1.3 million tonnes per year x 20 years / 0.9 tonnes/m3);

Above-grade perimeter side slopes no steeper than 4(H):1(V) (note: H denotes horizontal and V denotes vertical);

Above-grade top slopes no flatter than 20(H):1(V);

Below grade side slopes no steeper than 3(H):1(V); and

Minimum 1 m thickness of vegetated final cover soil.

The apparent waste density of 0.9 tonnes/m3 is representative of what has been achieved at the Site to date. Other criteria, specific to various features, were established in the design process.

4.3 Limits of Landfilling The approved pre-expansion waste fill limits for the Old Landfill, West Landfill and South Landfill are shown on Drawings 2 and 3. The total of the approved waste fill areas is 131 ha.

The waste fill limit for the proposed expansion is shown on Drawing 4. The proposed expansion will increase the waste fill area by approximately 55 ha for an overall waste fill area of approximately 186 ha. The Old Landfill waste fill area (55.2 ha) will remain unchanged; the proposed Area A will add a waste fill area of 32.1 ha to the existing West Landfill (55.3 ha) for a combined waste fill area of 87.4 ha; the proposed Area B will add a waste fill area of 22.8 ha to the existing South Landfill (20.3 ha) for a combined waste fill area of 43.1 ha.

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4.4 Base Contours The following objectives were pursued in the design of the base contours of the proposed expanded landfill areas:

Achieve overall target capacity of 28.9 million m3 in conjunction with the final contours of the landfill surface;

Establish the landfill base in unweathered clayey silt till;

Provide base grades appropriate for long-term leachate collection; and

Satisfy the MECP Reasonable Use Guideline for protection of off-Site groundwater quality.

The base contours represent the excavation surface upon which the leachate collection system will be constructed (refer to Section 7.6 for the leachate collection system description).

4.4.1 Proposed Old Landfill Base Contours The proposed Old Landfill vertical expansion will not require a base grade design. The existing cover soil on the Old Landfill will be stripped prior to landfilling in the expansion airspace.

The relatively minor lateral infill proposed for the Old Landfill is referred to as the proposed East Infill and is within the existing approved waste fill area. See Drawing 4 for the location of the East Infill. The proposed East Infill will have a base excavated at 3(H):1(V) side slopes and a flat bottom area at elevation 194 m above sea level (mASL) as shown in Drawing 11. A review of the Borehole Logs prepared for this area (Gartner Lee Limited, 1981) indicates that the weathered (brown) till zone extends to depths as much as approximately 3.5 m below original ground (i.e., to approximately elevation 194.8 mASL). The flat bottom area of the East Infill was set at elevation 194 mASL, which will be approximately 0.8 m below the maximum depth to the base of the unweathered (grey) till at this location. The below grade 3(H):1(V) side slopes for the East Infill will have a 0.6 m thick recompacted clay liner over their entire surface area (from crest to floor of the cell). The recompacted clay liner will provide lateral leachate migration control for the East Infill.

The exposed excavation will be visually inspected prior to liner or leachate collection system construction. In the event that the weathered till zone is encountered below elevation 194.8 mASL the base excavation will be lowered at localized areas as needed to have the compacted clay liner keyed into the unweathered clay till.

Sand seams encountered on the cell floor during cell excavation will be subexcavated and backfilled with clay and compacted. Sand seams encountered in the excavation sideslopes will be covered with the compacted clay liner. It is noted that these more permeable seams are localized and not continuous.

4.4.2 Proposed Area A and Area B Base Contours As mentioned in Section 4., the horizontal expansion of the West Landfill and South Landfill are referred in this report as Area A and Area B, respectively.

The proposed base contours for Areas A and B were designed in general consistency with the design of the existing West and South Landfills, respectively. The proposed base grades of Areas A and B (Drawings 12 and 13) are described below:

A central ridge running north-south will divide the total leachate drainage area in two and will allow flow of leachate towards the toe of the east and west perimeter side slopes;

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The base will have a series of alternating ridges and valleys that will run east-west with a 2% crossfall. Valleys on the east side of the central ridge will drain from west to east. Valleys on the west side of the central ridge will drain from east to west;

Four low points (denoted “L.P.” on Drawings 12 and 13) was designed to collect leachate and allow the installation of sumps to extract collected leachate. A low point was designed at each of the following locations: west side of Area A, east side of Area A, west side of Area B and east side of Area B;

The grades of the ridges and valleys are consistent with the Geotechnical Assessment Technical Memorandum prepared by Golder Associates dated March 29, 2019 (Sub-Appendix D6-A – Geotechnical Assessment Technical Memorandum for Grading Design Basis). To accommodate settlement of the landfill subgrade under the weight of the waste fill, the ridges and valleys will be graded at 1.2% under the area where the final cover 4(H):1(V) side slopes will be located and at 1% under the area where the final cover 5% top slopes will be located (see Sub-Appendix D6-A);

The lowest point of Area A base grades will be at elevation 188 mASL, which will be approximately 11 m below approximate existing ground elevation of 199 mASL, not including a 1 m deep sump; and

The lowest point of Area B base grades will be at elevation 188.5 mASL, which will be approximately 11.5 m below approximate existing ground elevation of 199 mASL, not including a 1 m deep sump.

The base grade side slopes will be no steeper than 3(H):1(V) and will be lined with a 0.6 m (minimum) thick compacted clay liner.



4.5 Final Contours The following objectives were pursued in the design of the final contours of the proposed expanded fill areas:

A peak elevation (top of final cover) at 241 mASL. This will be 0.3 m below the zoned Outer Surface of the Chatham Airport. Permanent features are not permitted to penetrate the Outer Surface;

Achieve the overall target capacity of 28.9 million m3 for waste and daily cover in conjunction with the base contours. This airspace volume excludes final cover volume and leachate collection system volume; and

Maintain perimeter side slopes no steeper than 4(H):1(V) and top surface slopes no flatter than 20(H):1(V) as required by O.Reg. 232/98 (MOE 1998).

The final contours for the proposed expansion are shown on Drawing 4. The Old Landfill will be expanded vertically by approximately 30 m. The Old Landfill, West Landfill and South Landfill will have a maximum height of approximately 42 m above original ground level.

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4.6 Landfill Capacity Calculations The air space volume between the base and final contours on Areas A and B, and between the base/existing and final contours on the Old Landfill represent the air space volume available for construction of a leachate collection system, the landfilling of approved waste and application of daily, intermediate, and final cover. The volumes for the proposed landfill expansion were calculated using AutoCAD-based computer design software. The proposed landfill expansion design will provide a landfill capacity of 28.9 million m3 for waste and daily cover, which is adequate to meet the target landfill capacity requirement of 28.9 million m3 for the 20-year planning period as discussed above.

The landfill contours, apparent density and waste tonnages will be tracked and included in the Annual Report. Closure will occur when the proposed expansion reaches design capacity. Design capacity will be based on reaching final design contours.

4.7 Soil Balance The soil excavation and fill volumes for activities involved with landfill construction, landfill operations and closure were calculated and are summarized in Table 4.1 below.

Table 4.1: Soil Balance

Description Quantity

Area A, B and East Infill Base Excavation 4,070,000 m3

Surplus from Existing Landfill Operations 230,000 m3

Strip and Recover Existing Cover 680,000 m3

Stormwater Ponds Excavation 350,000 m3

Flood Control Facility Expansion 200,000 m3

Daily/Interim Cover Requirement Assuming 7:1 Waste to Cover Soil Ratio (by volume) - 3,600,000 m3

Final Cover Requirement -1,300,000 m3

Screening Berms Requirement -500,000 m3

Perimeter Roads/Berms Requirement -95,000 m3

Soil Surplus 35,000 m3

Notes: 1. A 7:1 waste to cover ratio (by volume) was determined based on the historical usage of daily cover since 2000 and it is relatively low

compared to industry standards ratio of 4:1 because the Ridge Landfill accepts daily alternative daily cover that is tracked as waste. 2. The soil surplus will be used for the construction of roads and landfill perimeter berms, or placed in stockpiles, as shown on Drawing 4.

5.0 SITE FEATURES Most of the Site features already exist under the current approval, and include the Site entrance, on-Site roads, weigh scales and scale house, administration and maintenance buildings, landfill gas management facility, leachate storage and pumping facility, stormwater ponds, flood control facility, municipal drains, stockpiles and screening berms.

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5.1 Site Entrances The existing main entrance located on Erieau Road (as shown on Drawing 4) will continue to serve as the main entrance. This entrance is landscaped to enhance overall visual appearance of the Site. The main entrance connects to the main access road that has an access control gate located approximately 550 m west of Erieau Road. This location allows trucks waiting to enter the landfill to queue within the landfill property.

There are also three other access points to the Site (refer to Drawing 4) that are to only be used for service, maintenance or emergency purposes:

The former Site entrance on Erieau Road will be converted to the Leachate Management Entrance. This existing entrance provides access to the Old Landfill and Existing/Future Leachate Management Area;

A Service/Emergency Site Access is proposed off Erieau Road. The main purpose of this entrance will be to provide access to the Existing/Future Landfill Gas Management Area; and

Another entrance is located off Charing Cross Road (Country Road 10). It utilizes an existing gap in the Charing Cross Road (County Road 10) berm. The access road extending from the entrance crosses the Howard Drain relocation and connects to the West Landfill perimeter road.

All emergency entrances have locked gates that tie into perimeter fencing.

5.2 On-Site Roads At the western limit of the Old Landfill area, the main access road turns southwards and continues about 1,000 m to provide access to the West Landfill and South Landfill. The main access road will be extended by approximately 600 m to provide access to expansion Area A and Area B.

The main access road has two lanes, a paved surface and gravel shoulders along its entire length. There will be drainage ditches along the sides of the road.

Single lane maintenance perimeter roads are constructed around the Old Landfill, West Landfill and South Landfill. The roads are gravel surfaced, 4.0 m wide, and encircle the fill areas. The perimeter roads will be extended around expansion Area A and Area B.

An access road will be provided to the Existing/Future Leachate Management Area. Another access road will provide access to the Existing/Future Landfill Gas Management Area.

A 12 m wide equipment road adjacent to the 4 m wide perimeter gravel surfaced road is proposed south of Area B. This proposed equipment road will be used to haul soils from Area A and Area B excavation during cell construction and will also allow movement of large heavy equipment such as compactors.

Maintenance access to the relocated Howard Drain will be provided by 4-m wide gravel surfaced roads located at the perimeter of Area A and Area B, perimeter berms of stormwater ponds or at the toe of screening berms.

Temporary haul roads over the waste fill area will be constructed as needed to provide access to the landfill working face. These roads will have a gravel surface to help to control dust emissions from waste haul trucks compared to them travelling on soil. Waste materials, such as wood chips or autoshredder waste, may be used as an alternative building material for these temporary haul roads. After certain sections of the proposed expansion are complete, permanent roads built with concrete rubble or gravel will remain as service roads to the top of the landfill.

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5.3 Weigh Scale and Scale House An inbound weigh scale, an outbound weigh scale and a scale house is located on the main access road (before it turns south) near the northwest corner of the Old Landfill. This scale location ensures that a queue (line of trucks) behind the scale is contained on the property.

A bypass lane exists on the south side of the outbound scale. The bypass lane runs east approximately 250 m beyond the weigh scales.

5.4 Administration and Maintenance Buildings The Administration Building contains office space for management and administrative staff. Two (2) Maintenance Buildings will be used for maintenance, cleaning and storage of landfill equipment. The Maintenance Building located further south includes a hot box, which will be used to thaw frozen waste loads in the winter.

The Maintenance and Administration Buildings will be equipped with methane detection systems to provide warning of any build-up of methane gas concentrations.

5.5 Existing/Future Leachate Management Area The leachate collected at the fill areas will be stored in the leachate storage tank located in the Existing/Future Leachate Management Area. From the leachate storage tank, leachate will be pumped off-Site through a forcemain for treatment at the Blenheim Wastewater Treatment Lagoons (BWTL).

The Existing/Future Leachate Management Area will accommodate an additional transfer pump and leachate storage tank that may be installed in the future at Waste Connections’ discretion, although not required.

Leachate management is discussed in detail in Section 7.0.

5.6 Existing/Future Landfill Gas Management Area The first phase of the landfill gas collection system was installed in the West Landfill in August 2008 and installation and commissioning of a flaring system was undertaken in late 2009. The landfill gas collection system has been progressively expanded to portions of the West Landfill and South Landfill when they reached final grades.

The landfill gas collection system will be expanded to collect landfill gas from the proposed landfill expansion areas. Additional flares will be installed at the Existing/Future Landfill Gas Management Area to combust the collected landfill gas from the proposed landfill expansion areas. Any form of landfill gas utilization that may become economically viable in the future may be constructed in the Existing/Future Landfill Gas Management Area.

Landfill gas management is discussed in detail in Section 8.0.

5.7 Stormwater Management Ponds Surface water will be collected at perimeter ditches around the waste fill areas and discharged to stormwater management ponds (stormwater ponds). The stormwater ponds will provide surface water quality and quantity control. There are currently five stormwater ponds on the Site (stormwater ponds 1 to 5). Refer to Drawings 2 and 4 for existing and proposed stormwater ponds, respectively. Refer to Drawing 22 for drainage catchment areas.

Stormwater ponds 1 and 2 are located east of the Old Landfill, receive runoff from the east portion of the existing Old Landfill and discharge to the Duke Drain. Stormwater pond 1 will be expanded and stormwater pond 2 will be either expanded or relocated to accommodate additional runoff from the proposed landfill expansion.

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Stormwater pond 3 is located along the south limit of the West Landfill, receives runoff from the south end of the West and South Landfills and discharges to the Howard Drain. This stormwater pond will be decommissioned to allow construction of Area A. Runoff currently collected by stormwater pond 3 will be directed to stormwater ponds 4 and 7.

Stormwater pond 4 is located along the north limit of the West Landfill and will receive runoff from the west half of the West Landfill and west portion of Area A. Stormwater pond 5 is also located along the north limit of the West Landfill and will receive runoff from the west portion of the Old Landfill and the east half of the West Landfill. Both stormwater ponds 4 and 5 will discharge to the flood control facility located on the north side of the West Landfill and will be expanded to accommodate additional runoff from the proposed landfill expansion.

In addition to the expansion of stormwater ponds 1, 2, 4 and 5 described above, two new stormwater ponds (stormwater ponds 6 and 7) will be constructed to accommodate additional runoff from the proposed landfill expansion. Pond 6 will receive runoff from the east and south portion of Area B and will discharge to the Duke Drain. Pond 7 will receive runoff from the west portion of Area B and east and south portions of Area A and will discharge to the Howard Drain.

In summary, the proposed landfill expansion will require:

Stormwater pond 3 decommissioning;

Stormwater ponds 1, 4 and 5 expansion;

Stormwater pond 2 expansion or relocation; and

Stormwater ponds 6 and 7 construction.

Surface water management is further discussed in Section 6.0.

5.8 Flood Control Facility A flood control facility, located along the western perimeter of the landfill property, was constructed in 1999. The flood control facility controls runoff from the entire upstream drainage area including the relocated Duke, Howard and Scott Drains, as well as outflow from the Ridge Landfill Property. The outlet ties into the existing Howard Drain at the north Site boundary. Upstream flood levels and discharges are controlled by the hydraulic capacity of the Howard Drain downstream of the Site. In terms of flood hazard management, the flood control facility serves to maintain peak flows along the receiving watercourse at or below existing levels for the 250 year Regional Storm event, in conjunction with the on-Site stormwater ponds.

The existing flood control facility covers an area of approximately 10 ha and provides a total storage volume of approximately 269,000 m3. The existing flood control facility has a bottom elevation of 194.75 mASL, top of berm elevation of 197.4 mASL and maximum side slopes of 2(H):1(V).

The flood control facility will be expanded by approximately 7 hectares for a total of approximately 17 hectares area, will maintain the same water elevations as the existing flood control facility and will have its storage capacity increased by 196,000 m3 for a total of 465,000 m3.

A vegetative planting scheme will be incorporated into the flood control facility to enhance surface water quality and nutrient removal prior to out-letting to the Howard Drain downstream.

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5.9 Municipal Drains The Ridge Landfill Site contains a network of man-made municipal drains that convey surface drainage in the vicinity of the Landfill Site. Surface water will be received by four municipal drains (Howard, Scott, Duke and Lewis Drains), which are tributaries of the Flook and Hinton Drains. The Howard, Scott, Duke, and Lewis Drains are open drainage channels constructed under the provisions of the Drainage Act.

Various repairs and improvements have been completed along the Howard, Scott and Duke Drains within the Ridge Landfill, including the relocation of portions of these drains to facilitate landfill construction activities.

The proposed landfill expansion will require the relocation of the Howard Drain on the south side of Area A. The proposed expansion of the flood control facility and stormwater ponds 4 and 5 will require the relocation or abandonment of the Lewis Drain (see Drawing 4).

5.9.1 Howard Drain The Howard Drain is a grass-lined trapezoidal channel with a minimum depth of 2 m, 10 m bottom width, 2(H):1(V) side slopes and an invert (bottom) graded at 0.15% on average. The Scott Drain enters the Howard Drain at the southwest corner of the existing West Landfill. Drainage from the Scott Drain flows through culverts under the Charing Cross Road screening berm and outlets into the Howard Drain. The Howard Drain continues north around the west side of the West Landfill and passes through the flood control facility where it merges with the Duke Drain.

The segment of the Howard Drain located to the south of the existing West Landfill will be relocated further south to accommodate the Area A expansion. The proposed relocation of the Howard Drain involves the construction of approximately 1,600 m of new drain and the removal of approximately 1,300 m of the existing drain. The relocated segment of the Howard Drain consists of a 10 m bottom width with 2(H):1(V) side slopes, invert (bottom) graded at 0.1% and a minimum depth of 2.8 m. A hydraulic model was developed by using the software program HEC-RAS to evaluate the hydraulic characteristics of the relocated segment of the Howard Drain under the 250 year design flow scenario. The results of the model indicate that the proposed channel design for the Howard Drain relocation would provide sufficient hydraulic capacity to convey the 1 in 250 year design flow. A culvert will be required to convey Howard Drain flows beneath the screening berm that is proposed to be constructed along Allison Line. The results of the hydraulic analysis indicate that twin 5.1 m x 3.6 m box culverts (or equivalent) will be required at this location.

5.9.2 Duke Drain The Duke Drain is a grass-lined trapezoidal channel that extends from Allison Line and proceeds north on the west side of Erieau Road to the southeast corner of the Old Landfill. Over this section, the drain is 2 m deep, with a 3 m bottom width and 2(H):1(V) side slopes and 0.1% average bottom grade. At this point, the drain crosses under Erieau Road in a culvert and continues to flow north on the east side of Erieau Road in a larger trapezoidal channel, 2 m deep, with a 6 m bottom width and 2(H):1(V) side slope while maintaining an average bottom grade of 0.1%. At the northeast corner of the Old Landfill, the drain crosses back under Erieau Road via a culvert crossing. The drain continues west an additional 200 m and expands into a larger channel with a 10 m bottom width and 2.4 m deep at an average bottom grade of 0.08% and 2(H):1(V) side slopes. The drain continues travelling west along the north side of the Old Landfill and discharges to the flood control facility while merging with the Howard Drain.

The Duke Drain will be shortened to accommodate the flood control facility expansion (see Drawing 4). Approximately 450 m of the north 2(H):1(V) slope of the Duke Drain will be removed to allow direct connection with the expanded flood control facility.

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Approximately 120 metres of the Duke Drain will be filled at the area immediately north of the existing Administration Building to accommodate the construction of the Ancillary Facilities. This modification will change the location where the Duke Drain merges with the flood control facility (Drawing 4).

5.9.3 Lewis Drain The Lewis Drain is a relatively small municipal drain. The Lewis Drain originates west of the Northeast Woodlot and crosses the north property line. It flows north and conveys on-Site surface runoff from the Northeast Woodlot.

An approximately 250 m length of the Lewis Drain will be modified or abandoned to accommodate the flood control facility expansion. The affected potion of the Lewis Drain is in the upstream end and is located on-Site. A new ditch will be constructed, if required, to drain the area and connect to the remaining portion of the Lewis Drain that will not be affected (see Drawing 4).

5.9.4 Summary of Municipal Drain Modifications In summary, the proposed expansion will require the following modification to the existing municipal drains:

Relocation of Howard Drain;

Modifications of Lewis Drain; and

Modification of Duke Drain.

No changes are proposed to the Scott Drain. Approval for these modifications will be applied for under the Drainage Act, which is administered by the Municipality of Chatham-Kent.

5.10 Stockpiles Topsoil and soil from the excavation of the landfill cells, municipal drain relocations, stormwater ponds and flood control facility will be stockpiled on-Site at areas shown on Drawing 4 or other temporary locations for future use.

There are two proposed Topsoil Stockpile locations for the Ridge Landfill expansion. Topsoil Stockpile 1 will be located in the same location as the existing topsoil stockpile south of the Old Landfill and east of the South Landfill. Topsoil Stockpile 2 will be located east of the Topsoil Stockpile 1 across the proposed 2-lane road.

There are two proposed Soil Stockpile locations for the Ridge Landfill expansion. Soil Stockpile1 will be located in the southeast corner of the Ridge Landfill and will merge with the proposed screening berm in the southeast corner of the Ridge Landfill. Soil Stockpile 2 will be located west of the Northeast Woodlot.

Exposed portions of a soil stockpile that become inactive during the growing season (April to October) for an extended period of time will be seeded to establish vegetative growth.

5.11 Screening Berms The Ridge Landfill currently has screening berms that provide adequate screening of the existing Site operations to mitigate potential effects such as visual, noise and other potential nuisances from off-Site locations. The existing screening berms will be modified to accommodate the proposed landfill expansion as described below. For existing screening berms refer to Drawing 2 and for proposed screening berms refer to Drawing 4.

Erieau Road Screening Berms. The existing screening berms along the eastern Ridge Landfill property boundary along Erieau Road are approximately 4 metres high and have trees planted on the berm crest to enhance screening along Erieau Road (Erieau Road screening berm). The Erieau Road screening berm will

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be extended until the intersection with Allison Line and will have a height of approximately 7 metres, or higher as required for additional screening. In addition, a portion of the existing Erieau Road screening berm may be modified to match the height of the proposed berm as an option to further enhance the screening as needed. This existing/proposed berm is planned for naturalization.

Allison Line Screening Berm. The existing 700 m long screening berm south of the existing South Landfill will be removed to accommodate Area B expansion. This berm will be replaced with a new screening berm along Allison Line (Allison Line screening berm). The proposed Allison Line screening berm will be approximately 1,800 m long extending along the entire southern limit of the Ridge Landfill property along Allison Line and will be approximately 7 m high or higher as required for additional screening. The existing berm that will be removed is grass covered; however, the proposed new berm is planned for naturalization.

Charing Cross Road Screening Berms. The existing screening berms along Charing Cross Road are approximately 1,800 m long and 7 m high (Charing Cross Road screening berms). They provide screening along the western boundary of the Ridge Landfill property. A minor extension will be required near the Allison Line intersection. This existing berm has some landscaped areas for ornamental purposes and do not provide additional visual screening; however, this existing berm is planned for naturalization.

The proposed screening berms will have a 4(H):1(V) side slopes along the roadsides to support landscaping that includes a variety of native species including shade trees, evergreen trees and shrubs that are selected to enhance local flora and fauna. The interior side slopes of the screening berms will be 3(V):1(H).

5.12 Woodlots The Ridge Landfill currently has three woodlots (see Drawing 2). The Northeast Woodlot is located at the northeast corner of the Ridge Landfill property. The Southeast Woodlot is located south of the Old Landfill and east of the existing South Landfill. The Southwest Woodlot is located south of the West Landfill. The Southwest Woodlot will be removed to allow expansion of Area A. The other two existing Woodlots will remain.

5.13 Public Waste Drop-Off and Processing Facilities The public waste drop-off and processing facilities will be included in the Ridge Landfill operations in the areas discussed below. The approved soil processing and composting facility has never been operated and is proposed to be removed from the ECA.

5.13.1 Public Waste Drop-Off Area The existing Public Waste Drop-Off Area used by local residents and located in the portion of the Old Landfill area identified as the Infill Area (Drawing 2) will be relocated to the Proposed Ancillary Facilities area shown on Drawing 4. The Public Waste Drop-Off Area will consist of bins placed on a gravel pad to allow vehicles to drive in and unload waste materials to be landfilled. The public waste vehicles will pass over the weigh scale to have the load weight recorded.

5.13.2 Future Public Recycling Area A Future Public Recycling Area/Drop-Off is also contemplated for future operations at the Ancillary Facilities area. The Public Recycling Area will likely consist of bins placed on a gravel pad to allow vehicles to drop-off materials that could be used on-Site or shipped to end markets.

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5.13.3 Beneficial Use Materials Laydown Area It is intended that wood and concrete will be the main construction and demolition (C&D) waste stream materials received and processed at the Ridge Landfill. Also, secondary materials to be received and separated for subsequent re-use may be shingles and glass.

Wood chipping operations are currently carried out in the Infill Area within the Old Landfill approved waste fill limit. Processing of wood waste only occurs on a seasonal basis and will be completed by a contractor that will bring in a mobile grinder unit as required. The wood chips are used on-Site as temporary road surface, mulching or as daily cover.

Concrete stockpiling and crushing operations are currently carried out in the Infill Area within the Old Landfill approved waste fill limit. Concrete crushing only occurs on a seasonal basis and will be completed by a contractor that will bring in a mobile crusher unit as required. The crushed concrete will be used on-Site as road base.

Once the Infill Area of the Old Landfill is modified for landfilling of waste, both the wood chipping and concrete crushing operations will move to either the Beneficial Use Materials Laydown Area 1 located at the southeast corner of Area A or to the Beneficial Use Materials Laydown Area 2 located immediately east of the Southeast Woodlot.

6.0 SURFACE WATER MANAGEMENT PLAN 6.1 Drainage Design Goals and Objectives The overall goal of the proposed surface water management plan will be the protection and preservation of the upstream and downstream drainage system. This will be achieved through the adoption of an integrated strategy that combines Site design features, best operational management practices, and practical stormwater management practices.

The following specific objectives were developed for the surface water management plan.

6.1.1 Water Quality ▪ Enhanced level of water quality protection (80% suspended solids removal efficiency).

▪ To preserve and protect the long-term sustainability of the downstream and upstream watershed, the stormwater management plan will incorporate measures to achieve the following:

▪ Prevent the discharge of leachate into the Site surface water collection system;

▪ Avoid and/or minimize the delivery of sediment and suspended solids from the Site to the receiving watercourses;

▪ Prevent and/or minimize excessive thermal warming of Site drainage;

▪ Eliminate and/or minimize the potential for increased off-Site nutrient transport to the receiving watercourse; and

▪ Avoid the introduction of contaminated surface waters into the subsurface environment or off-Site watercourses.

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6.1.2 Water Quantity and Erosion Control To eliminate and/or minimize the potential for increased flood risk both upstream and downstream of the Site,

peak flow rates and flood elevations will not exceed existing levels for all storm events up to and including the 250-year Regional Storm.

To avoid and/or minimize the potential for increased erosion, flow velocities in the receiving drainage system will be maintained at current levels or lower.

To prevent and/or minimize changes in the flow regime along the receiving drainage system, runoff hydrographs (i.e., timing, duration) following Site development will maintain the existing condition hydrographs to the extent possible.

To account for impacts associated with climate change, the stormwater management system will be sized to accommodate the future mean rainfall conditions projected for the year 2050 at the Ridgetown RCS Climate Station. Note that future climate change rainfall projections were determined by Risk Sciences International (RSI, 2019).

6.2 Surface Water Plan Components The surface water management plan consists of a number of distinct components, which collectively have been designed to achieve the intended objectives. The following describes and discusses the components comprising the proposed plan.

6.2.1 Water Quality 6.2.1.1 Separation of Leachate from Surface Water Drainage System The Site design includes both a surface water drainage system and a leachate collection system, which were designed to operate as separate systems.

Any surface water in contact with waste will be considered leachate. Leachate produced on-Site will be collected by the leachate collection system, temporarily stored in the leachate storage tank and pumped by forcemain to the BWTL. No leachate will be discharged to drainage ditches, watercourses, or municipal drains outside of the waste fill areas.

The on-Site non-contact surface water drainage system will consist of perimeter ditches along the perimeter of the Old Landfill, West Landfill/Area A and South Landfill/Area B. The perimeter ditches will be graded to low points that allow collected stormwater to discharge into the stormwater ponds through culverts.

The surface water drainage system includes sufficient storage that in the event of a leachate break-out or emergency spill, discharge of water from the Site will be collected by the perimeter ditches and contained by the stormwater ponds for all storms up to and including a 100 year, 24 hour event.

6.2.1.2 Restricted Use of Fertilizers, Pesticides, Herbicides and Road Salt The operation and maintenance of the Landfill Site requires from time-to-time the use of fertilizers, pesticides and herbicides. Presently, the use of the above noted materials is anticipated to be limited, and no more significant than that typically applied by municipalities in maintaining open spaces. Only those materials approved under the Ontario Pesticides Act and local municipal by-laws will be used. Road salt will not be used due to its potential effect on surface water and on groundwater monitoring results.

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6.2.1.3 Dust Control Plan Part of the design and operation of the Site includes routine watering of hard surfaced on-Site roads and pervious areas. The dust control plan will limit the build-up of dust and other non-point source pollutants, which will decrease the amount of pollutants in the first flush from these areas following runoff-producing rainfall events. As a result, the performance of the stormwater ponds (described below) for removing suspended solids and nutrients in storm runoff is expected to exceed that of SWM ponds constructed to serve urban developments.

Only water that meets the approved discharge criteria will be used to water the roads for dust control to control potential impacts to surface water and groundwater.

6.2.1.4 Site Grading Where possible, Site grading is designed so that slopes draining surface water runoff will be minimized. Utilizing more gentle slopes and longer flow paths for surface drainage produces lower velocities and minimizes the potential for erosion.

6.2.1.5 Buffer Zone To protect the watercourses adjacent to the Site, vegetated buffer zones have been established, where possible, and will remain undisturbed.

6.2.1.6 Stormwater Ponds Key design considerations and assumptions adopted to determine the preliminary stormwater pond design requirements include the following:

The stormwater ponds will operate in batch mode during the operating life of the Landfill and in a passive/continuous discharge configuration following the closure of the Landfill;

The stormwater ponds have been sized to provide quantity/flood control for the mean adjusted 100 year, 24 hour event under the 2050 future climate change scenario, with additional flood control storage for the 250 year Regional Storm event provided by the flood control facility;

Minimum 0.5 m permanent storage depth;

3(H):1(V) side slopes;

Inclusion of a flow control valve at the Pond outlet structures to temporarily detain surface runoff to allow batch mode operation during the operating life of the Landfill;

Provision of an emergency overflow weir; and

The top of the stormwater pond berms will be 0.25 m minimum above the emergency overflow weir to provide an allowance for freeboard.

Consistent with current operating procedures, the stormwater ponds will operate in batch mode during the operating life of the Site, with outflows from each stormwater pond restricted such that all intercepted runoff will be contained for an extended period of time. Release of stormwater will be controlled manually (via a flow control valve) and outflows will discharge to the receiving watercourses several times annually. This method of control will provide increased water quality treatment, minimize potential flood and erosion impacts to the receiving watercourses, and

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function as an emergency containment system in the event of surface water contamination, potential leachate breakouts or potential spills.

6.2.2 Water Quantity and Erosion Control 6.2.2.1 Internal Conveyance System The internal conveyance system will continue to be designed and operated to eliminate nuisance flooding effects and maintain a separation of surface water from the active landfill area and leachate collection system.

Perimeter ditches were designed to convey surface water runoff generated by rainfall events up to the 25-year storm event plus an allowance for climate change.

The proposed perimeter ditches were designed with a triangular v-shape grassed channel with 3(H):1(V) side slopes, a depth of 1.2 m and a 0.5% grade. Perimeter ditches graded at 0.2% will be trapezoidal grassed channels with 3(H):1(V) side slopes, a depth of 1.2 m and a 1.5 m wide flat bottom design.

The internal ditches/grassed swales were designed such that backwater from the stormwater ponds (discussed below) will not produce flooding of internal roads and other Site facilities.

6.2.2.2 Stormwater Ponds The stormwater ponds will provide both flood and erosion control, as well as water quality treatment benefits for all non-contact surface water runoff generated from the fill areas, interior roads, buildings, parking areas and processing facilities.

In terms of quantity control, the ponds serve to:

Maintain peak flows generated from the expanded Site at or below existing levels for the 100 year, 24 hour storm event; and

Provide extended detention storage to regulate outflows to levels that prevent and/or minimize changes to the downstream receiving drainage system.

Table 6.1 below summarizes the minimum volume requirements for the stormwater ponds based on modelling.

Table 6.1: Minimum Volume Requirements for Stormwater Ponds

Pond No.

Permanent Pool Volume Requirement

(m3) Active Storage Volume Requirement (m3) Total Volume

Requirement (m3)

1 2,230 18,056 20,286

2 1,610 13,532 15,142

3 To be decommissioned as discussed in Section 5.7.

4 3,680 44,953 48,633

5 6,725 84,244 90,969

6 2,750 33,585 36,335

7 4,650 92,357 97,007

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Stormwater ponds 5 and 7 will be significantly larger in volume and area than the other stormwater ponds and for this reason they will have low level dividing berms to provide operational flexibility and facilitate maintenance activities. The low level dividing berms will be located at the center of stormwater ponds 5 and 7 (see Drawing 4). The low level dividing berms will have a flow control valve that will be kept in closed position and an overflow weir at an elevation approximately 0.10 m below the emergency weir overflow elevation to allow overflow from the first half to the second half of these ponds. During the operating life of the Landfill, when the stormwater stored in the first half of these ponds will be tested and confirmed it meets the approved discharge objective, the flow control valves will be opened for discharge into the receiving water bodies. Following discharge, the flow control valves will be closed back to normal operating mode. The dividing berm also provides an extra access for litter pick-up or other maintenance activities.

6.2.2.3 Flood Control Berm Stormwater pond 7 will have the west berm at elevation 200 mASL to maintain the minimum 2.8 m depth of the relocated Howard Drain and to provide flood control for the areas south of Area A and Area B.

6.2.2.4 Municipal Drain Modifications The relocated Howard Drain to the south of Area A will allow the replication of pre-development drainage patterns as closely as possible and have been designed to minimize or eliminate flooding. For additional details and description of modification of the Lewis Drain and Duke Drain, refer to Section 5.9.

6.2.2.5 Flood Control Facility The flood control facility is located along the north portion of the Ridge Landfill property. The expanded flood control facility will provide additional storage to attenuate flows for the 250 year Regional Storm event. The flood control facility is described in Section 5.8.

6.2.2.6 Surface Water Diversion Berms Surface water diversion berms will be constructed above the final cover to control erosion of the 4(H):1(V) side slopes of the Old Landfill, West Landfill and South Landfill. The surface water diversion berms will convey water to downchutes that connect to the perimeter ditches. The location of the surface water diversion berms and downchutes were designed to not impact the catchment area of the stormwater ponds (see Drawings 22 and 23).

The surface water diversion berms will be constructed directly above the soil final cover. The surface diversion berms will be 0.6 m high with a 0.6 m wide berm crest and having side slopes of 3(H):1(V). The swale created between the surface water diversion berms and the 4(H):1(V) cover will be lined with an erosion control blanket and will be graded at 3% to 5% towards down chutes that connect to the perimeter toe ditches. The down chutes will be lined with a geotextile filter and riprap to control runoff erosion and velocity, respectively.

7.0 LEACHATE MANAGEMENT SYSTEM 7.1 Leachate Management Objectives The leachate management system for the expanded Site has been designed to comply with the MECP requirements for both groundwater and surface water.

The MECP policies and objectives regarding surface water quality are outlined in the document entitled “Water Management Policies, Guidelines Provincial Water Quality Objectives” (MOE, 1994b).

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The document contains the Provincial Water Quality Objectives, which are a set of narrative and numerical criteria designed for the protection of aquatic life and recreation in and on the water. The objectives represent a desirable level of water quality that the MECP strives to maintain in surface water.

The policy concerning groundwater is described in Guideline B-7: Incorporation of the Reasonable Use Concept into MOEE Groundwater Management (MOEE, 1994a). This is referred to as the Reasonable Use Guideline (RUG). The guideline describes the basis for limiting contaminant concentrations in groundwater on properties adjacent to landfills. Meeting the RUG requires the proponent to determine the reasonable use of groundwater on the adjacent property and then design the landfill such that the maximum concentration of a particular contaminant is predicted to be in compliance with Guideline B-7 at the landfill property boundary.

As a minimum, the leachate management objectives for the design of the Ridge Landfill will comply with the requirements of the PWQO for surface water, and with the requirements of the RUG for groundwater.

The design of the landfill has been assessed with respect to achieving these objectives. This assessment is presented in the Appendix D7 – Hydrogeological Impact Assessment of the EA Report. Actual performance will continue to be assessed by environmental monitoring (refer to Section 15.2).

7.2 Leachate Management Philosophy The philosophy for leachate management adopted for the Ridge Landfill consists of the following key aspects:

Controlled leaching of contaminants. It is desirable to permit infiltration in the design of the final cover of the landfill to reduce the contaminating life span of the landfill; and

Containment, collection, removal and treatment of leachate. Because the contaminating life span depends on the removal of contaminant mass from the landfill, leachate collection and removal must accompany containment. Without collection and removal, leachate will tend to mound within the containment system. These rising leachate heads will increase the potential for contaminant release through the barrier below the landfill. If mounding is allowed to progress to ground surface above the containment system, leachate will discharge to surface. To prevent these releases, leachate collection and removal are necessary.

7.3 Leachate Characterization Leachate characteristics vary depending on:

Age of the landfill;

Material being landfilled;

Landfill operation (type of cover, thickness of waste, waste lift layering and compaction); and

Moisture input to the landfill (intensity, duration, and frequency of rainfall and moisture content of solid waste going to the landfill).

The leachate characteristics change seasonally and over time. As the landfill ages, there is a shift from a relatively short period of aerobic conditions in the landfill to anaerobic conditions.

Based on the historic leachate monitoring data available, the leachate quality at the Ridge Landfill is generally similar to typical municipal solid waste landfill leachate. Data on the Ridge Landfill leachate quality is provided in the annual monitoring reports.

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7.4 Final Cover Design The existing and proposed final cover design meet the following objectives:

Allow controlled infiltration of precipitation. Controlled infiltration will be encouraged because moisture flow through the waste will be essential for leaching and removal of contaminants from the landfill by leachate collection and removal.

Limit intrusion of air when the landfill gas collection system is operating. This will minimize air from being drawn into the landfill by the vacuum applied by the landfill gas collection system. The intrusion of air is undesirable in a landfill that has a gas collection system because it can upset the anaerobic methane-producing conditions (causing diminished gas generation), dilute the concentration of methane in the collected gas and increase the risk of spontaneous ignition of subsurface fires.

Support vegetation for landfill rehabilitation. The final cover will support vegetation so that, as part of the rehabilitation of the Site, the landfill areas can be integrated with the surrounding area and can possibly allow some alternative use after closure.

The objective of allowing infiltration of water cannot be met with a final cover that includes a low permeability hydraulic barrier such as a geomembrane. As such, consistent with the existing fill areas, an un-compacted native soil cover has been selected for the proposed expansion (refer to Section 7.5). A benefit of soil covers is that they act as a passive biofilter, resulting in reductions in odorous emissions from the landfill. The biofiltration effect will continue to operate indefinitely.

The overall thickness of the final cover is:

1.5 m for the existing West Landfill and South Landfill;

1.0 m for the existing Old Landfill; and

1.0 m for the proposed expansion areas, i.e., Old Landfill expansion, Area A and Area B.

All existing and proposed final cover thicknesses include a 0.15 m thick topsoil layer to support vegetative growth. A cross section of the final cover for the proposed expansion is shown on Drawing 24 (Detail 1).

Following placement of the cover soils and topsoil, the closed portions of the Site will be hydraulically seeded, using a mix of shallow rooted and early successional species of grasses. The goal is to establish a mixture of annual species that establish quickly and perennial species that will remain over the long term and will control erosion. Seed type and percentage will be determined in accordance with the Standard Roadside Mix included in the OPSS.MUNI 804 Seed and Cover as amended from time to time. The post-closure revegetation plan will be included in the Closure Plan for the Site. If necessary, a follow-up reseeding will be undertaken to establish the revegetation.

As discussed in Section 6.2.2.5, surface water diversion berms and down chutes will be constructed above the final cover for erosion control purposes. These features are therefore part of the surface water/erosion control design, and not part of the final cover design.

7.5 Leachate Generation Leachate generation was estimated for the long-term condition after final cover has been applied. Percolation from the final cover was predicted using the Hydrologic Evaluation of Landfill Performance (HELP) computer program.

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The HELP model is a quasi-two-dimensional hydrologic model of water movement across, into, through and out of landfills (Schroeder et al., 1994).

The long-term average annual percolation was predicted by the HELP model to be approximately 150 mm for the final cover condition with compacted native cover soils. The modelling input parameters and results for the anticipated soil cover are presented in Sub-Appendix D6-B.

A percolation rate of 150 mm per year was therefore assumed for estimating the leachate generation for the pre-expansion and proposed expansion. With a fill area of approximately 131 ha, the approved waste fill area was predicted to have a long-term average annual leachate generation rate of about 540 m³ per day. With the expansion bringing the total fill area to about 190 ha, the long-term average annual leachate generation rate of the approved waste fill area and proposed expansion combined is estimated to be about 780 m³ per day.

7.6 Leachate Control System Design Approach and Rationale The leachate control system design approach for the existing Old Landfill is and will continue to be different from the design approach for the existing West and South Landfills. The Old Landfill uses a finger drain perimeter leachate collection system and a recompacted clay cut-off wall to control lateral movement of contaminants through the weathered zone of the clay till, except for the approved Infill Area and proposed East Infill, which use a recompacted clay side slope liner to control lateral movement of contaminants through the weathered zone of the clay till. The design of the West Landfill and South Landfill includes a full, continuous underdrain (drainage blanket) to collect leachate and a recompacted clay side slope liner to control lateral contaminant migration through the weathered zone of the clay till.

Modelling was performed to determine the groundwater impacts for the proposed expansion of the Old Landfill. The modelling determined that a perimeter collector system will continue to be adequate to control downward migration of contamination to acceptable levels. A recompacted clay cut-off wall or a recompacted clay side slope liner will continue to be required to control lateral leachate migration at the Old Landfill through the weathered zone. Therefore, the leachate control system for the expansion of the Old Landfill will continue to consist of a finger drain system and either a recompacted clay cut-off wall or a recompacted clay side slope liner. Further detail regarding the modelling results and the expected performance in terms of groundwater protection is provided in Appendix D7 – Hydrogeological Assessment of the EA Report.

Modelling was also performed to determine the groundwater impacts of the proposed expansion Area A and Area B. The modelling determined that a leachate collection system and liner design for Area A and Area B similar to the existing West Landfill and South Landfill design will continue to meet the Reasonable Use Guideline, i.e., a full continuous underdrain (drainage blanket) constructed over the native clay till soils and a recompacted clay liner constructed at the side slopes is proposed for Area A and Area B. Further details regarding the modelling results and the expected performance in terms of groundwater protection is provided in Appendix D7 – Hydrogeological Assessment of the EA Report.

The proposed leachate control designs are described in the following sections. Compliance of the design with the Engineered Facilities Guideline is addressed in Section 10.0.

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7.7 Leachate Control System Design for the Expansion of the Old Landfill Area

7.7.1 Existing Leachate Collection System The existing leachate collection system at the Old Landfill consists of finger drains with length ranging from 8 m (26 feet) to 23.8 m (78 feet), spaced approximately 60 m apart and connected to leachate collectors (perforated pipes embedded in clear stone) located along the perimeter of Mounds 1, 2 and 3 of the Old Landfill. Manholes are installed along the collectors at approximately 100 m spacing to facilitate maintenance (see Drawing 14).

Collected leachate is conveyed by gravity to two existing pump stations and then pumped via forcemain to the leachate storage tank. From the leachate storage tank, leachate is pumped to the municipal forcemain located along Erieau Road, which conveys leachate to the BWTL for treatment.

The existing compacted clay cut-off wall provides lateral migration control (see Section 7.7.5).

7.7.2 Expansion Design Approach An underdrain drainage blanket is not proposed for the Old Landfill. Section 10 (3) of O.Reg. 232/98 allows proponents to propose a site-specific design, provided that the design meets the Reasonable Use Guideline (RUG), which is the case for the proposed design of the Old Landfill. The Landfill Standards (MOE, 2012) provide specific guidance for site-specific designs as indicated below, including natural attenuation landfills. The following Sections of the Landfill Standards (MOE, 2012) are relevant to the approved site-specific design of the Old Landfill, including the East Infill:

Section 2.4 allows site specific aspects of landfill design and operation to be tailored to the conditions of a particular site;

Section 4.5 establishes the RUG to assess performance and compliance of site-specific landfill designs. In addition, this section specifically allows natural attenuation designs, i.e., the absence of engineered liners or leachate underdrain collection systems, for sites in thick clay deposits that meet the RUG, which is the case for the Old Landfill. This Section also mentions that for sites where there is significant natural groundwater protection (which is the case for the Old Landfill), the level of engineering can be relaxed and a site-specific design proposed; and

Section 4.5.1 allows two approaches for landfill design, i.e., either a site-specific design or one of the two generic designs established by O.Reg. 232/98. All design approaches will need to meet the RUG. The RUG assessment criterion is included in this Section. This Section also includes Section 10 (3) of O.Reg. 232/98 that is directly applicable to site-specific designs.

The Old Landfill and the East Infill Area are designed as a natural attenuation site because the hydrogeological conditions (i.e., the approximately 30 metres of low permeability soils beneath the landfill base) allow compliance with the RUG, the Landfill Standards and O.Reg. 232/98. In the event of a reduced level of performance or failure caused by clogging or other reasons, finger drains can be replaced in the future as needed. Also, additional finger drains could be installed in the future to reduce the spacing if needed.

7.7.3 Proposed Leachate Collection System Expansion The design for the expansion of the existing leachate collection system was prepared to accommodate the proposed expansion of the Old Landfill area. The main purposes of the leachate collection system are to control lateral

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migration of leachate beyond the perimeter of the Old Landfill and to control leachate mounding height within the waste. The design of the proposed expansion of the Old Landfill area is that it will have neither a base liner nor an underdrain leachate collection system; rather, it will be an expansion in general consistency and integration with the existing leachate collection system of the Old Landfill.

The design incorporates a minor infill located on the eastern portion of the Old Landfill. This minor infill is labeled as the East Infill and will be located within the boundaries of the approved maximum waste footprint limit (Drawing 14). For cross-sections, refer to Drawing 18 and for details refer to Drawing 20.

7.7.4 Proposed East Infill Base The proposed East Infill will have a base excavated at 3(H):1(V) side slopes and a flat bottom area at elevation 194 m above sea level (mASL). A review of the Borehole Logs prepared for this area (Gartner Lee Limited, 1981) indicates that the weathered (brown) till zone extends to elevation 194.8 mASL. The flat bottom area of the East Infill was set at elevation 194 mASL, which will be approximately 0.8 m below the upper extent of the unweathered (grey) till at this location. The below grade 3(H):1(V) side slopes will have a 0.6 m thick compacted clay liner over their entire length down to the floor of the cell. The compacted clay liner will provide lateral leachate migration control (Drawings 15, 18 and 20).



7.7.5 Proposed Perimeter Drain and Finger Drain Design It is proposed that finger drains be installed under the existing soil cover of the Old Landfill. These finger drains will have minimum dimensions of 1 m wide, 3.7 m deep and 25 m long. The 25 m length was selected as this will terminate the finger drains at an elevation corresponding approximately to the leachate levels measured on February 24, 2017, i.e., at elevation 202.6 mASL (12 m above base grades) within the Old Landfill (Dillon Consulting, 2018a). The 25 m long finger drains will be longer than the maximum length of the existing perimeter finger drains, which range from 8 m (26 feet) to 23.8 m (78 feet).

The proposed finger drains will be spaced at a maximum distance of 25 m. This will be less than half the distance of the spacing for the existing finger drains (i.e., 61 m or 200 feet).

The calculations to support the finger drain depth of 3.7 m and spacing of 25 m are presented in the Sub-Appendix D6-C.

Outside the Infill and East Infill limits, the proposed finger drains will be constructed with clear stone and will be connected to new perimeter collector pipes (perforated pipes), which will discharge leachate to the existing manholes. The new perimeter collector pipes will provide a redundancy to the existing perimeter leachate collection system.

Inside the East Infill limits, the proposed finger drains will be constructed with clear stone and will be connected to a continuous clear stone drainage blanket placed on the below grade 3(H):1(V) side slopes (Drawing 18). At the bottom elevation of the clear stone drainage blanket will be a 200 mm diameter perforated HDPE pipe along the full

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length of the blanket. A 200 mm diameter solid HDPE pipe will connect to the perforated pipe at intervals to convey the collected leachate to new manholes (Drawing 20). A separate 200 mm diameter solid HDPE pipe will convey leachate by gravity from the manholes into the existing manholes or Pump Stations.

The performance of the proposed engineered perimeter leachate control systems was evaluated to support the proposed design. The performance evaluation of the proposed perimeter drain is found in the Ridge Contaminant Transport Modelling Memorandum attached to the Hydrogeological Impact Assessment Report (Appendix D7 of the EA Report). A maximum leachate mounding of approximately 17 metres above the landfill base was estimated at the centre of the Old Landfill expansion. This is an acceptable mounding height since the resulting impact on groundwater quality meets the O.Reg. 232/98 Reasonable Use Guideline. For context, the leachate mounding at the Old Landfill was measured on February 24, 2017 at a maximum height of approximately 12 metres above base grades, which is approximately 5 metres below the maximum mounding height predicted for the proposed expansion.

The performance of the proposed finger drains was also evaluated. As documented in Sub-Appendix D6-C (Calculation of Mounding Between Finger Drains), the maximum leachate mounding was calculated as 3.7 m high, measured from the bottom of the finger drains, which means that leachate is expected to remain underneath the final cover at the perimeter of the landfill and as a consequence the potential for leachate seepage will be controlled.

7.7.5.1 Design Peer Review The finger drain design approach was peer reviewed by Dr. Kerry Rowe1 as required by the MECP.

The peer review Memorandum dated January 9, 2020 issued by Dr. Kerry Rowe concludes that the proposed site-specific design is considered acceptable to control leachate seepage on the side slopes. See Sub-Appendix D6-D for peer review Memorandum dated January 9, 2020.

7.7.6 Temporary Interior Slope Berms To control potential adverse effects from leachate seepage from the temporary interior slopes of vertical expansion Cells O1, O2 and O3, temporary interior slope berms along the length of the toe of the temporary interior slopes are included in the design. Cell O4 does not have temporary interior slopes. The purpose of these temporary interior slope berms is to prevent overland discharge of seepage from the interior side slopes and allow it to infiltrate into the underlying waste.

Low points along the temporary interior slope berms will have infiltration trenches to drain the side slope seepage impounded by the temporary interior slope berms. Drawing 6 shows the location of the temporary interior slope berms and infiltration trenches for Cells O1 to O3. Detail C included in Drawing 20 shows a typical cross-section of the temporary interior slope berms and infiltration trenches. The temporary interior slope berms will be 1 m higher than the existing final cover. The interior toe of these berms will be about 3 m away from the toe of the temporary interior slopes of Cells O1 to O3. The top portion of the existing final cover between the toe of the temporary interior slope berms and the toe of the temporary interior slopes will be removed to allow infiltration while still providing odour control. This design allows the collection of both seepage and stormwater that could potentially runoff

1 Dr. Kerry Rowe is a Professional Engineer, author of over 300 refereed journal papers, 3 books, 14 book chapters, and more than 300 full conference papers; he has extensive research and consulting experience in geosynthetics, waste management and geo-environmental engineering including the design and/or peer review of hydrogeology and/or design for more than 60 landfills in Canada, US and other countries; in 1999, he received the Ontario Ministry of the Environment’s Award of Excellence for Research and Development for his work on the clogging of leachate collection systems; he was the key advisor developing technical aspects of Ontario's current landfill regulation O.Reg. 232/98; he spent 22 years as a professor, including 8 years as Chair of the Department of Civil and Environmental Engineering, at The University of Western Ontario; he is presently a Professor and the Canada Research Chair in Geotechnical and Geo-environmental Engineering in the Department of Civil Engineering at Queen’s University.

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overland and reach stormwater ponds. The location and dimensions of the temporary interior slope berms may be adjusted to suit Site conditions. The infiltration trenches will be 2 m to 15 m long as shown in Drawing 6 and will be 0.5 m deep as shown in Detail C of Drawing 20. The infiltration trenches may be made deeper or longer to suit Site conditions.

7.7.7 Seepage Diversion Berm As an additional measure against potential leachate seeps along the contact between the existing and proposed expansion waste fill emerging on the side slopes, it is proposed to construct a seepage diversion berm using clay soil along the permanent exterior side slopes of the Old Landfill expansion. The purpose of this berm is to block potential leachate seepage that may be migrating laterally along the existing/new waste interface before it emerges on the surface and cause it to infiltrate into the waste and/or direct it to the finger drains. This berm will be located at the toe of the permanent exterior side slopes of the proposed expansion as shown in plan view on Drawing 6 and cross-section on Drawing 18. This berm will be 1.2 m higher than the existing waste and will have a base width that will vary to suit Site conditions. This berm will be constructed as part of the final cover.

7.7.8 Lateral Control Measures A perimeter clay cut-off wall exists at the perimeter of the Old Landfill, except for the Infill area. The existing perimeter compacted clay cut-off wall is a low-permeability barrier that was designed to control lateral movement of groundwater into or leachate out of the landfill through the weathered zone of the clay till. The existing cut-off wall consists of native clay till recompacted in a trench 1.2 m wide, completely surrounding the landfill as well as the pumping stations, forcemains and header pipes. The compacted clay cut-off wall is keyed into the unweathered clay till to a minimum depth of 0.6 m (Drawing 18). The compacted clay cut-off wall can be replaced in the future if needed.

Lateral control at the Infill and East Infill will be achieved with a 0.6 m thick recompacted clay liner installed over the full length of the below grade 3(H):1(V) side slopes down to the floor of the cell (Drawing 18). The recompacted side slope liner construction will be monitored with a testing program for compacted density, moisture content and hydraulic conductivity of the recompacted clay.

Since the recompacted clay side slope liner consists of native clay soils, its service life is expected to be greater than the contaminating life span of the landfill.

7.8 Leachate Control System Design for Expansion of the West and South Landfills (Areas A and B)

The base contours of Areas A and B are discussed in Section 4.4.2. The leachate collection system for Areas A and B expansions will consist of a full underdrain (continuous drainage blanket). Typical sections of the proposed leachate collection system design are shown on Drawings 19 and 21. The proposed leachate collection system for the Areas A and B consists of the following components:

Leachate collection lateral pipes oriented in the east-west direction on both sides of the base central ridge. The leachate collection lateral pipes will be 200 mm diameter perforated high density polyethylene (HDPE) DR11 pipes, spaced 50 m apart, located at each valley of the base. The drainage path before leachate intercepts a collection pipe has a maximum length of 31.5 m (Drawing 21, Detail 1). To accommodate settlement of the landfill subgrade under the weight of the waste fill, the ridges and valleys will be graded at 1.2% under the area where the final cover 4(H):1(V) side slopes will be located and at 1% under the area where the final cover 5% top slopes will be located (see Sub-Appendix D6-A – Geotechnical Assessment

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Technical Memorandum for grading design basis). The structural integrity of the pipes was reviewed. The existing pipes for the South Landfill vertical expansion and the proposed pipes for the lateral expansion are designed to withstand the design load, with factors of safety well above (i.e., by 70% to 185%) the recommended factors of safety (Sub-Appendix D6-E);

A leachate collection header pipe along the toe of the cell excavation side slopes along the entire perimeter of Areas A and B will collect leachate from lateral pipes and convey leachate from the lateral pipes to sumps located at the low points. The leachate collection header pipes will be 200 mm diameter perforated HDPE DR11 pipes. The header pipes will be graded at 0.5% minimum and connect to the leachate collection lateral pipes;

Non-perforated 200 mm diameter HDPE DR11 riser pipes will extend from the lateral pipes and headers, up the below-ground 3(H):1(H) side slopes to clean-out ports above ground surface at the edge of the fill area. The riser pipes allow for maintenance activities such as insertion of cameras for visual inspection and hydraulic jets for cleaning;

Four low points (denoted “L.P.” on Drawings 12 and 13) were designed to collect leachate and allow the installation of sump pumps to extract collected leachate. A low point was designed at each of the following locations: west side of Area A, east side of Area A, west side of Area B and east side of Area B;

450 mm diameter perforated HDPE extraction pipes at each sump. A redundant extraction pipe will be included to each sump as a contingency;

On the floor of the cells, a 50 mm nominal diameter clear stone drainage layer consisting of a continuous blanket 0.15 m thick at the drainage divide between collection pipes (ridges) and 0.43 m thick at the collection pipes (valleys) will be constructed. On the below-ground 3(H):1(V) side slopes, the 50 mm clear stone drainage layer will be 0.3 m thick. This drainage blanket geometry is part of a site-specific design approved by the MECP in 2011 for all future landfill cells of the Ridge Landfill (see below for site-specific design discussion and additional details);

Two non-woven geotextiles, one laid at the bottom and another laid at the top of the 50 mm clear stone drainage layer;

A 0.2 m thick sand protective layer above the drainage layer; and

Sump pumps will be installed to pump leachate from the low points of Areas A and B to the leachate storage tank via forcemains. From the leachate storage tank, leachate will be pumped by the on-Site transfer pump that connects with the off-Site municipal forcemain to convey the Ridge Landfill leachate blended with municipal wastewater to the BWTL for treatment.

In 2011, a site-specific design for the drainage blanket of the leachate collection system was approved by MECP for the construction of future cells under Condition 3.2(2) of the ECA No. A021601. This ECA Condition approved the site-specific drainage blanket of future cells in accordance with the information provided in Items 77 through 79 in Schedule A of the ECA. Items 77 through 79 of the ECA Schedule A are attached (Sub-Appendix D6-F) and discussed below.

Item 77 of the ECA Schedule A (Cover Letter, Application Form and Report): On December 16, 2010 a cover letter, ECA amendment application form and a report supporting the application for approval of a site-specific design

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was submitted to MECP. The report supporting this application, entitled Ridge Landfill – Leachate Collection System Amendment and dated November 2010 (herein referred as Report) is summarized below.

The purpose of the application was to obtain approval for a site specific, optimized design of the drainage blanket that meets or exceeds the minimum standards for a 100-year service life outlined in O.Reg. 232/98 (Schedule 1) and on which the Ridge Landfill expansion groundwater impact assessment was based. O.Reg. 232/98 permits a site specific design that uses alternative design criteria where shown to be appropriate (Section 4.5 of the Landfill Standards Guideline).

The 100-year service life of a leachate collection system presented in O.Reg.232/98 for a generic design is known to be conservative. The service life calculation presented in O.Reg. 232/98 is based on a method developed by Dr. Kerry Rowe in 1994. The Report used the same method to calculate the service life of the drainage layer as that in Schedule 1 of O.Reg. 232/98. The Report, including the site-specific design calculations of the service life and conclusions was reviewed by Dr. Kerry Rowe (see Appendix A of the Report for confirmation). For Dr. Kerry Rowe’s bio, refer to Section 7.7.4 above.

Schedule 1 of O.Reg. 232/98 requires a maximum drainage path length of 50 m. The drainage path length to the collection pipes in the Ridge Landfill leachate collection system averages 25 m (either 18.5 m or 31.5 m). This reduced drainage path for the Ridge Landfill helped with the thickness reduction of the drainage layer while achieving the 100-year service life.

In addition, the Ridge Landfill leachate collection system has a 200 mm sand protective layer above the clear stone drainage layer (separated by a geotextile), which enhances the performance of the leachate collection system as it will help protect against migration of fines from the waste into the clear stone drainage layer.

The Ridge Landfill site specific design meets or exceeds other requirements of Schedule 1 of O.Reg. 232/98 such as stone gradation, stone thickness below and above the pipes and minimum 0.5% grade toward the leachate collection pipes.

One of the key parameters for the service life calculation equations is the calcium concentration dissolved in leachate. The 10-year average calcium concentration at the Ridge Landfill leachate at the time of the Report preparation was 328 mg/L (2000-2009), which was significantly lower than the 1,500 mg/L concentration used in the calculations of the Schedule 1 of O.Reg.232/98. The laboratory analytical results for calcium in leachate samples from 2010 to 2018 were reviewed, and ranged from 130 mg/L in 2016 to 470 mg/L in 2012, i.e. have remained comparable with the values used in the Report and significantly lower than the 1,500 mg/L concentration used in the calculations of the Schedule 1 of O.Reg.232/98. The leachate quality for the landfill expansion will be comparable to current and historical leachate quality because the type of waste and the maximum waste thickness (for lateral expansion) will not change and therefore the site-specific drainage layer design applies to the proposed expansion. All other parameters used in the design service life calculations, i.e., geometry and porosity of the drainage blanket and infiltration of 150 mm/year will remain unchanged for the proposed expansion, which supports the conclusion that the site-specific design approved for the West and South Landfills is applicable to the proposed lateral expansion of Areas A and B and the minor vertical expansion of the South Landfill.

Item 78 of the ECA Schedule A (MOE Review Letter): On March 28, 2011 the MOE provided comments on the application and requested additional drawings showing the locations where the collection system was not yet constructed (i.e., where the site-specific design would be applicable) and a revised final contour plan showing

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changes as a result of the reduced thickness of the drainage blanket. Note that these requests were to submit clarifications and indicated the initial acceptance of the site-specific design.

Item 79 of the ECA Schedule A (Letter to MOE and Attachments): On April 11,2011 a cover letter providing background and the requested drawings were provided to the MECP reviewer.

The ECA amendment was issued by MECP shortly after the submission of the additional information noted above. For convenience, Items 77 to 79 of the ECA Schedule A are provided in Sub-Appendix D6-F. Seven (7) cells have been constructed using the approved site-specific design, i.e., Cells 4B East, 4A, 4B, 5A, 5B, 6 and 7.

The site-specific design contemplated under O.Reg. 232/98 and approved by Condition 3.2(2) of the ECA No. A021601 is applicable to the proposed lateral expansion of the West and South Landfills, which includes a minor vertical expansion of the South Landfill.

7.8.1 Lateral Control Measures A recompacted clay liner is proposed for the side slopes of Areas A and B, consistent with the existing West and South Landfills. This proposed compacted clay liner will be constructed with native clay material to control the lateral movement of groundwater into or leachate and LFG out of the landfill through the weathered zone of the clay till. The recompacted clay side slope liner will be 0.6 m thick, will extend from the top to the base of the 3(H):1(V) side slopes and will enclose the leachate collection, header, riser and extraction pipes of the underdrain leachate collection system. The cross-sections shown on Drawings 19 and 21 illustrate the recompacted clay side slope liner.

The side slope liner construction will be monitored with a testing program for compacted density, moisture content and hydraulic conductivity of the recompacted clay.

7.8.2 Future Toe Drain A future toe drain will be installed around the proposed Areas A and B and existing West and South Landfills at the toe of the 4(H):1(V) landfill side slopes. The purpose of the future toe drain is to allow for leachate to be collected at the perimeter of the landfill cells after failure of the underdrain leachate collection system. This will reduce the potential for the development of leachate seeps and impacts to surface water when leachate eventually mounds within the landfill. The future toe drain will be constructed at the end of the service life of the underdrain leachate collection system, which is estimated at just above 100 years.

The toe drain will consist of a 10 m wide, 0.5 to 1.0 m thick, drainage trench of 50 mm clear stone at the toe of the side slopes. The toe drain will be integrated with the side slope drainage layer of the leachate collection system. A non-woven geotextile filter will envelop the full thickness of the drainage blanket. A perforated 200 mm diameter HDPE pipe will be installed in this layer. It will drain by gravity to the pumping stations.

7.9 Leachate Storage Tank and Transfer Pump Capacity Review Based on HELP model estimates discussed in Section 7.5, the long-term annual average leachate generation rate will increase from about 540 m3 per day to about 780 m3 per day, i.e., the overall leachate annual average rate will increase 44% with the proposed landfill expansion. These generation rates are at the landfill post-closure phase assuming the final cover is 100% constructed. The maximum annual peak leachate generation rate is expected to be about 919 m3/day in 2040 when the waste footprint is fully constructed and some portions of the landfill are operating and do not have final cover.

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The leachate collected at all fill areas (Old Landfill, West Landfill and South Landfill) will be stored in the existing on-Site leachate storage tank located in the Existing/Future Leachate Management Area (Drawing 4). The existing on-site leachate storage tank is a glass-fused steel structure and has a 605 m3 storage capacity. Although not required for capacity reasons, Waste Connections may decide to install a second leachate storage tank of approximately the same capacity during the expansion period to provide redundancy and allow for tank maintenance without leachate removal interruption.

Leachate is currently stored at the leachate storage tank and then pumped to the off-Site municipal forcemain along Erieau Road. The transfer pump is an above ground Gorman-Rupp pump equipped with an enclosure and has a capacity of 23.3 L/s (2,013 m3/day). This existing pump has sufficient capacity to transfer the projected maximum leachate generation to the BWTL (refer to Sub-Appendix D6-G – Ridge Landfill On-Site Leachate Infrastructure Memo for details). Although not required for capacity reasons, Waste Connections may decide to install a second on-Site transfer pump of the same capacity during the expansion period for additional redundancy, operational flexibility and minimal leachate removal interruption.

7.10 Off-Site Leachate Municipal Forcemain Review The capacity of the existing off-Site 200 mm diameter municipal forcemain was evaluated for the maximum expected leachate generation rate of 919 m3/day. The evaluation concluded that the existing off-Site 200 mm diameter municipal forcemain has sufficient capacity to transfer the projected maximum leachate generation quantities to the BWTL (refer to Sub-Appendix D6-H – Ridge Off-Site Leachate Infrastructure Memo for details).

7.11 Leachate Recirculation Option Leachate recirculation can be a useful and effective measure to manage leachate if well controlled and done moderately on a temporary basis. Recirculating leachate back into the landfill is a means to defer leachate disposal by taking advantage of the moisture holding capacity of the waste. Other potential benefits of recirculation, such as accelerated landfill stabilization and degradation of organic components of the waste, accelerated landfill gas production, partial treatment of leachate, and equalization of leachate flow and character, may be achieved. Recirculation does not, however, result in the overall contaminant mass being removed from the landfill. As such, it does not contribute to reducing the contaminating life span of the landfill with respect to non-degradable contaminants (e.g., chloride). Leachate recirculation may be used on a temporary basis as a contingency option in case the BWTL no longer accepts leachate for treatment.

7.12 Leachate Treatment/Disposal Leachate from the existing waste fill areas (Old Landfill, West Landfill and South Landfill) is currently conveyed to the on-Site leachate storage tank. It is then pumped through the municipal forcemain to the BWTL for treatment. This is the preferred leachate disposal option (Dillon, 2018b). Refer to the attached Sub-Appendix D6-H – Ridge Off-Site Leachate Infrastructure Memo for a description and details including treatment capacity of the BWTL.

7.12.1 Off-Site Capacity and Treatability Assessment The BWTL’s ability to treat existing and future leachate quantities and quality associated with the proposed landfill expansion is documented in the attached Sub-Appendix D6-H – Ridge Off-Site Leachate Infrastructure Memo. The key findings and conclusions are summarized below:

The BWTL receives leachate from the Ridge Landfill and wastewater from Charing Cross and Blenheim. The future (year 2040) maximum volume of leachate projected for the Ridge Landfill including the proposed

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expansion is 919 m3/day on average. The future (year 2040) volume of wastewater projected for Charing Cross and Blenheim is estimated at 1,724 m3/day on average. Therefore, the total maximum average future (year 2040) volume of combined leachate and wastewater to be treated at the BWTL is 2,643 m3/day;

Based on the current BWTL ECA No. 6023-APPN4Q, the average daily rated hydraulic capacity is 4,045 m3/day, with a peak flow rated capacity of 12,046 m3/day. Approximately 70% of the current approved hydraulic capacity of the BWTL will be needed in 2040, i.e., 30% of the facility’s hydraulic capacity will still be available;

This Memo concludes that the BWTL have available capacity to treat future leachate quantities associated with the proposed expansion; however, the Total Kjheldhl Nitrogen (TKN) concentration in the leachate may not meet the discharge criteria for the facility in the future;

It is recommended that effluent quality from the BWTL continue to be monitored to allow future assessment of the necessity for additional TKN removal at the BWTL. Specifically, the TKN concentrations in the leachate and in the effluent from the BWTL will be monitored to plan for the need for additional treatment capability. Waste Connections has an agreement in place with the Chatham-Kent Public Utilities Commission to allow the continued discharge of leachate to the BWTL; and

Should an on-Site pre-treatment facility be required in the future, it would be located in the Existing/Future Leachate Management Area in the vicinity of the existing leachate storage tank east of the Old Landfill.

8.0 LANDFILL GAS MANAGEMENT SYSTEM The following sections present a summary of the landfill gas (LFG) management objectives, projected rates of LFG generation and describe the design of the landfill gas control system (LFGCS) for the proposed landfill expansion at the Ridge Landfill.

8.1 Gas Management Objectives The purpose of the Site landfill gas (LFG) system is to manage LFG generated within the landfill areas and to mitigate any potential effects on human health and the environment. The specific objectives of the LFGCS are to:

Minimize subsurface migration of LFG from the waste fill areas to the extent practicable;

Minimize atmospheric LFG emissions (including odour bearing components) from both uncompleted and completed landfill areas to the extent practicable; and

Incorporate flexibility to accommodate potential future LFG utilization.

LFG utilization (e.g., energy recovery) is currently being pursued and will depend on market conditions and available technology. The LFG system is designed to allow for future LFG utilization.

8.2 LFG Generation Rates for the Entire Landfill The LFG generation rates for the Ridge Landfill expansion were estimated using the Landfill Gas Emissions Model (LandGEM) Version 3.02. The LandGEM model was developed by the United States Environmental Protection Agency (USEPA) and is a first order decay model that estimates generation rates for total LFG and specific gas constituents such as methane, carbon dioxide, non-methane organic compounds, and individual air pollutants from MSW landfills.

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LFG generation is a function of waste tonnages in place, annual waste disposal rate and two parameters that are specific to the type of waste and influenced by environmental conditions (i.e., Lo - potential methane generation capacity and k - methane generation rate).

The following parameters were used in the LFG generation model for the Ridge Landfill:

Landfill opening year: 1966;

Methane generation rate (k): 0.040/year; and

Potential methane generation capacity (Lo): 125 m3/Mg.

In addition, the following closure years were assumed in the model:

Landfill closure year for the do-nothing condition (i.e., the Ridge Landfill is not expanded): 2021; and

Landfill closure year for the expansion condition: 2041.

The historical waste tonnages were obtained from the following sources:

1996 Appendix M - Atmospheric Studies for the waste tonnages from 1965 to 1994; and

Annual Ridge Landfill Operations Reports from 1995 to 2017.

The waste tonnages from 2018 to the landfill closure year were estimated based on the average of waste tonnages for the last three (3) years (i.e., from 2014 to 2017) and were rounded to the nearest thousand tonnes.

The LandGEM model was used to estimate total LFG generation rates. The modelling process and input parameters described above are consistent with the 1996 Appendix M - Atmospheric Studies Report and the Annual NPRI Reporting that was prepared by RWDI for the Ridge Landfill for the 2017 reporting year (RWDI, 2018).

The model results for LFG generation rates over time for the proposed Ridge Landfill expansion is presented in the following Figure 8.1.

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Figure 8.1: Landfill Gas Generation Results for the Entire Landfill

The LFG generation quantities illustrated by Figure 8.1 are for total LFG generation (i.e., it includes all gas constituents). The units for generation rate are standard cubic feet per minute (scfm). It should be noted that LFG modelling without the benefit of actual measurements collected and proper model calibration is an inexact science. Model results can vary, perhaps substantially, from actual LFG generation rates. Caution should always be exercised when using LFG generation rates derived from first order decay modelling. It is further noted that the values above are for LFG generation rates and an active LFG management system would not collect 100% of the LFG generated, i.e. a fraction of the generated LFG is typically collected.

The LFG generation quantities above are for the entire Ridge Landfill, i.e., for the Old Landfill, West Landfill and South Landfill combined.

8.3 LFG Collection Rates for the Entire Landfill The LFG collection rates were obtained by multiplying the modelled LFG generation rates by an assumed collection efficiency. This method has many uncertainties and caution should be used for detailed design/equipment selection purposes. A collection efficiency range of 65-85% has been used by Golder in other landfill preliminary studies. In a recent landfill approval project, an 80% collection efficiency was requested by MECP. For the purposes of this Design and Operation Report, an 80% collection efficiency factor has been assumed.

The annual waste tonnages, annual LFG generation rates and LFG recovery rates, assuming a collection efficiency of 80% are attached as Sub-Appendix D6-I for the do-nothing condition (i.e., no expansion and landfill closure in 2021) and as Sub-Appendix D6-J for the proposed expansion condition. The reason that the LFG estimates for the do-nothing condition were included is so that net changes related to the proposed expansion may be determined as part of the EA.

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Based on the data inputs, the LFG model approximated the maximum LFG collected at Ridge Landfill would be approximately 18,700 m3/hour (11,000 scfm), or 5.2 cubic meter per second, and will occur in 2041/2042, coinciding with the anticipated closure of the proposed expanded waste fill areas.

8.4 LFG Assessment for the Existing Waste of the Old Landfill A LFG generation and collection efficiency assessment was completed for the existing waste of the Old Landfill, to evaluate the potential environmental benefit of temporarily collecting LFG from the existing waste prior to vertical expansion. The Old Landfill received waste between 1966 and 1999; as such, the waste in the Old Landfill was placed between 54 and 20 years ago. The LFG predictions completed for the existing waste of the Old Landfill (see Figure 8.2 below) show that the peak LFG generation at 1,500 scfm happened in 2000, the year after disposal in the Old Landfill was completed.

Figure 8.2: Landfill Gas Generation Results for the Existing Waste of the Old Landfill

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The LFG generation has declined since that time and in the proposed 2021-2027 period for completion of the Old Landfill expansion is predicted to be approximately 650 to 500 scfm (average 575 scfm), or about one-third of the peak generation, and well along on the declining LFG generation curve. Since the expansion will proceed with filling in Cell O1, and assuming uniform gas generation over the area of the Old Landfill, there would only be temporary gas collection from Cells O2, O3 and O4 or three-quarters of the landfill area, i.e., 375 – 485 scfm (average 430 scfm) of the ongoing generation.

Acknowledging that a landfill gas collection system is not 100 percent effective, the following factors were considered in estimating a landfill gas collection efficiency for the existing Old Landfill:

The existing leachate mound level in some areas of the Old Landfill is high, leaving only about 4 to 5 m of unsaturated zone below the existing top surface in some areas from which to temporarily collect LFG. It is also noted that any temporary LFG collection approach would have to be isolated for some distance below the surface to minimize air intrusion, thereby further reducing the thickness of the potential gas capture zone.

Old Landfill mounds 1 and 2 (i.e., approximately 2/3 of the Old Landfill area) were filled using the trench and fill method, which included vertical soil barriers between trenches. Vertical soil barriers would limit the LFG collection efficiency using either horizontal collectors or vertical wells.

The Old Landfill used a large amount of clay soil as daily cover and some clay stockpiles were buried within the waste according to the landfill operations staff. The presence of this clay, which has a lower hydraulic conductivity than the waste, will further compartmentalize the waste and further reduce LFG collection efficiency.

The geometric configuration of the Old Landfill (i.e., a large footprint area of approximately 50 ha combined with a shallow unsaturated zone as little as 4 m below landfill surface) will minimize LFG collection efficiency.

In view of these unfavourable conditions, it is considered that a low temporary LFG collection efficiency in the 20 to 30% range is likely realistic. For temporary LFG collection from all of cells O2, O3 and O4, this would correspond on average to approximately 85 to 130 scfm over the 2021 to 2023 period; then reduced to two-thirds of this when filling commences in Cell O2; and reduced again by half when filling commences in Cell O3.

This quantitative analysis of LFG generation and potential temporary LFG collection from Cells O2, O3 and O4 of the Old Landfill supports the position that a temporary LFG control system for the existing waste of the Old Landfill will provide very limited environmental benefit and is not warranted. However, if LFG emissions are observed from the existing surface of areas of the Old Landfill prior to their receiving waste that could result in off-Site odour issues, temporary horizontal LFG collectors will be installed to provide odour control as needed.

8.5 Gas Collection System 8.5.1 Existing LFGCS The detailed design for the West Landfill gas collection system was completed by Dillon/SCS and approved by MECP under the ECA No. A021601. The detailed design for the South Landfill gas collection system was completed by Golder and approved by MECP under the ECA A021601. The Air and Noise ECA No. 7958-7BMQGT approved three flares of 3,600 sm3/hour (1 sm3/sec or 2,100 standard cubic feet per minute [scfm]) each and two blowers.

Construction of the first phase of the existing LFGCS was completed by Golder Construction. It started in 2008, with commissioning of the system occurring in late 2009. The existing LFGCS consists of vertical gas extraction wells

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and connections to the leachate collection system, condensate traps, two blowers and two flares, each with a capacity of 3,600 standard cubic metres per hour (sm3/hour) (2,100 standard cubic feet per minute [scfm]).

8.5.2 LFGCS Philosophy for the Proposed Expansion The expanded LFGCS system will be a similar, but expanded version of the existing LFGCS, which will be comprised of three major components:

LFG collection system (e.g., vertical gas extraction wells and/or horizontal collection trenches, wellheads, LFG header pipe, LFG sub-header, and later piping);

LFG control system (e.g., blowers and flares); and

Condensate management system.

Vertical gas extraction wells and horizontal collection trenches will be installed within the waste mass to extract LFG. The vertical gas extraction wells will be connected by a series of sub-header and lateral pipes connected to a perimeter header system that will convey the collected LFG to the LFG control system. Horizontal collection trenches will be connected in a similar fashion. The collected LFG will be ultimately combusted via a series of blowers and flares. The condensate formed in the LFG collection system and at the blower/flare stations will be collected and transferred to the facility’s leachate management system.

The following sections describe the conceptual design of the various LFG system components associated with the expansion areas.

8.5.3 Vertical Gas Extraction Wells The vertical gas extraction wells and LFG collection piping are primary components of a LFGCS. The number of vertical gas extraction wells and their layout are dependent on several Site-specific characteristics, including the existing and final topography, general cell design, along with the ability to connect to existing infrastructure.

The following design criteria were used for the proposed LFGCS expansion layout and placement of the vertical gas extraction wells:

Well Depth: minimum of 3.0 m above the leachate collection system;

Non-perforated Pipe: 5.0 m minimum below the top of final cover surface; and

Radius of Influence: 25 m.

The currently approved vertical gas wells are shown on Drawing 25 – Approved Final Contours with LFGCS (Pre-Expansion). The location of the proposed vertical gas extraction wells associated with the proposed LFGCS expansion for the landfill expansion areas is shown on Drawing 26 – Proposed Final Contours and LFGCS (Post-Expansion). Since the Old Landfill does not have an existing active gas collection system, the proposed LFGCS expansion infrastructure will be added to the Old Landfill as shown on Drawing 26 – Proposed Final Contours and LFGCS (Post-Expansion).

Some existing vertical gas extraction wells, sub-headers, and lateral piping located on the south slopes of the South Landfill and West Landfill, where the lateral expansion piggybacks over the existing LFG collection field infrastructure, will be replaced with new vertical gas extraction wells and associated piping. Existing vertical gas

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extraction wells, sub-headers, and lateral piping on top of the South Landfill and West Landfill will be protected and maintained, with existing vertical gas extraction wells extended vertically through the proposed vertical expansion.

Vertical gas extraction wells will be generally constructed as shown on Drawings 27 and 28. Each vertical gas extraction well will include a wellhead assembly to permit monitoring of LFG quality as well as controlling LFG flow.

The landfill gas collection system will be progressively expanded as new waste is placed and cells reach final grades. In addition, the landfill gas collection system will be expanded as needed to areas filled with new waste that become inactive for more than six months.

8.5.4 LFG Headers, Sub-headers and Laterals The existing LFGCS comprises a combination of perimeter LFG header pipes, on the West Landfill waste mound and around the South Landfill limit of waste within the perimeter access road. The existing LFG header pipes will be connected to a network of sub-header and lateral pipes that connect to each vertical gas extraction well. Each of the LFG header pipes will then tie into a main header pipe located within the main perimeter access roadway that will ultimately connect to the blower/flare stations located on the east side of the South Landfill.

The proposed LFGCS expansion will use a similar network of header, sub-header, and lateral pipes to collect and convey LFG to an expanded LFG control system. At this stage of conceptual design, it is anticipated that the existing main header pipe will be able to manage LFG flows from the expanded Old Landfill, West Landfill and South Landfill. If during detailed design it is determined that additional main header pipe capacity is required, the existing header pipes and main header pipe may be twinned to accommodate LFG flows from the vertically expanded Old Landfill and the laterally expanded West Landfill and South Landfill, or simply have a dedicated main header pipe servicing the vertically expanded Old Landfill.

The design will also incorporate redundant piping connecting both sides of any LFG header pipe to maintain LFG collection efficiencies should a sub-header pipe at some point on the landfill fail due to differential waste settlement.

8.5.5 Condensate Management LFG header piping will be designed to collect condensate within proposed low points that will be identified during the detailed design stage. These proposed low points will comprise condensate traps that will drain to the Site’s leachate management system at points such as leachate collection system cleanouts or nearby leachate collection system manholes.

Typical condensate traps that may be utilized include inline condensate traps and accessible condensate traps, both of which are shown on Drawing 28 – Details II, Detail 7 – Condensate Trap (Inline) (Typical), and Detail 8 – Condensate Trap (Accessible) (Typical). Liquids collected in the condensate traps will be pumped to the facility’s leachate management system, where they will be managed as leachate.

8.6 Gas Combustion The existing LFGCS collects LFG from both the West Landfill and the South landfill, channeling LFG to the LFG Control System and into a condensate knockout pot (i.e., moisture separator), centrifugal blowers, flame arresters and enclosed flares for combustion. The LFG Control System will be expanded with the addition of similar components, to handle the additional LFG flows associated with the proposed landfill and LFGCS expansions.

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LFG will continue to be routed through a knockout pot (i.e., moisture separator) that collects and remove entrained liquid droplets from the LFG stream to avoid corrosion within the blower system. The safety-shutoff valves serve as a safety feature to automatically shut-off gas flow upon shutdown of the LFGCS.

As previously noted, there are currently two flares installed on-Site and a third one will be installed under the current approval. Each blower/flare has 3,600 sm3/hour (2,100 scfm) capacity. With the additional estimated LFG flows, it is anticipated that additional flaring capacity will be needed in the future to accommodate the additional gas quantities associated with the proposed landfill expansion. Detailed design with equipment selection details will be submitted to MECP for approval following the EA approval.

8.7 Remedial Action for Landfill Gas Control The technology of landfill gas collection and management is well proven. If the performance of the gas collection system or blower/flare station plant is not adequate, improvements can be made to achieve the required performance. For gas collection, improvements could include addition of new wells/horizontal collectors, or alteration or closure of existing wells. Blower/flare station modifications could include alteration of equipment, gas treatment processes, or operating procedures.

9.0 LFG SUBSURFACE MIGRATION At landfill sites, the potential for lateral subsurface migration of LFG and associated potential explosion hazard of methane (should it migrate and collect in confined spaces) is commonly assessed. Methane gas is lighter than air, it is explosive when present at a concentration of between 5 and 15 percent by volume in air, and it migrates under both concentration and pressure gradients.

As landfill gas is generated within the landfill waste mass, a low pressure builds up and slowly pushes the gas through the pore spaces of waste or soil before it is released to the atmosphere. The gas moves through the path of least resistance. Permeability is a measure of how well gases or liquids flow through pore spaces. Dry, sandy soils have relatively high permeability (larger interconnected pore spaces available for gas to travel through) and would be a preferential gas pathway. On the other hand, clay has low permeability, i.e., it has small pore spaces and for this reason it inhibits the subsurface movement of landfill gas. If the soil is saturated (i.e., the pore spaces are filled with groundwater), landfill gas will not displace water in the pore spaces because the gas pressure does not have enough driving force to push the water through the soil pore spaces. In a site with a high groundwater elevation, the gas migration is limited to only the unsaturated pore spaces above the water table. A low permeability engineered compacted clay liner or cut-off wall serves as a physical barrier to landfill gas migration. An excavated stormwater management pond or a municipal drain containing water would also serve as a physical barrier to subsurface landfill gas migration since it would create a discontinuity in the gas pathway through the unsaturated soil zone.

LFG lateral subsurface migration potential is influenced by various site-specific factors such as type of native soil, groundwater elevation, landfill containment system design, and active LFG collection system. Methane gas explosion potential of migrated LFG depends on factors specific to the receptors, such as separation distance between the waste disposal areas and the receptor buildings, and construction characteristics and engineering controls at the receptor sites.

Based on the physical Site setting of the Ridge Landfill, potential migration of LFG through the subsurface is expected to be very limited due to the impermeable soils at the Site. The native silty clay soil is about 30 metres

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deep, is generally homogeneous and has a low permeability. In addition, the upper groundwater level in the surficial weathered soils is relatively shallow. Those two Site conditions are natural limiting factors for potential subsurface lateral migration of LFG between the waste disposal areas and potential receptors. In addition, it is noted that a recompacted clay side slope liner exists for the West and South Landfills and is proposed for Areas A and B. This proposed recompacted clay side slope liner will be constructed with native clay material to provide a low permeability barrier to potential migration of both leachate and LFG. The existing waste disposal areas were constructed with lateral containment systems (either recompacted clay cut-off walls or recompacted clay side slope liners). The lateral low permeability containment system adds an additional barrier to LFG migration. As well, there is a minimum 100-metre wide buffer between the proposed landfill footprint areas and the Site property boundaries; there are also municipal drains that would intercept the lateral migration of any LFG in the unlikely event that it had migrated away from the landfill through the thin unsaturated zone.

The proposed landfill expansion will have an active LFG collection system that will collect LFG and relieve LFG pressures in the waste mass, which will also control potential lateral subsurface migration of LFG.

10.0 COMPLIANCE WITH THE ENGINEERED FACILITIES GUIDELINE AND LANDFILL STANDARDS

The Engineered Facilities Guideline (MOEE, 1993), or Guideline C-13, applies to the following facilities and the component parts at the Ridge Landfill Site:

The landfill final cover;

The leachate collection systems;

The perimeter cut-off walls;

The recompacted clay side slope liner;

The toe drain system;

The leachate storage tank and the forcemains; and

The landfill gas collection and management facilities.

According to Procedure C-13-1 (under Guideline C-13) these facilities must meet five requirements, briefly described as follows:

It must be possible to monitor the engineered facility to verify that it performs to specification;

The contaminating life span of the landfill must be addressed in the contexts of the service lives of the various engineered facilities that are used to control contamination;

Provision must be made for the maintenance of an engineered facility and its operation for as long as is required;

Technical supporting data are required on the performance of engineered contaminant control facilities employing new technologies; and

It is the responsibility of the applicant to specify the time period for the decommissioning of an engineered facility.

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The Landfill Standards (2012) amended the definition of Engineered Facilities and included examples of common engineered facilities, if they are intended to be functional elements or features for more than five years:

Berms;

Drainage ditches;

Liners;

Covers;

Pumps;

Facilities to detect, monitor, control, collect, redirect or treat leachate, surface water or ground water; and

Facilities to detect, monitor, control, collect, redirect, treat, utilize or vent landfill gas.

Section 4.12.2 - Approval Guidelines of the Landfill Standards (2012) requires an engineered facility that is to be constructed at a landfilling site for purposes of controlling leachate, groundwater, surface water or landfill gas to be designed such that:

the service life of the engineered facility exceeds the contaminating lifespan of the landfill (i.e., the period of time during which contaminants may be generated by the site and need to be controlled by the engineered facility to prevent an unacceptable impact). Refer to Appendix D7 – Hydrogeological Impact Assessment of the EA Report for contaminating lifespan assessment; or

the engineered facility can be replaced, or an alternative engineered facility can be constructed, as necessary to enable the combined service lives of the engineered facilities to exceed the contaminating lifespan of the landfill.

For groundwater, an unacceptable impact is considered to be an increase in contaminant concentrations in excess of the maximum allowable concentrations defined in accordance with the MECP’s Reasonable Use Guideline.

For surface water, an unacceptable impact is considered to be an impact on a surface water feature in excess of the standards described in Section 4.9 of the Landfill Standards (MOE, 2012).

For landfill gas migration below surface, an unacceptable impact is considered to be the migration of landfill gas at concentrations in excess of the allowable methane concentrations defined in Section 4.10 of the Landfill Standards (2012).

The compliance of the various engineered facilities with the Engineered Facility Guideline and Landfill Standards for the various engineered facilities are discussed below.

10.1 Landfill Final Cover The final cover will be constructed with soil and readily accessible for repairs. Repairs include filling of erosion areas and depressions as required.

The vegetation on the final cover can be monitored by visual inspection (see Section 11.8.1). Repairs to the vegetative cover can be achieved through the addition of soil, reseeding, replanting, etc.

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The key goals for the final cover in the context of contaminating life span is to control water infiltration allowing 150 mm per year (minimum), mitigate emissions/odours and minimize air intrusion into the landfill gas collection system. The final cover therefore will be inspected, monitored, maintained and repaired as needed for the duration of the leachate and landfill gas contaminating life spans.

10.2 Leachate Collection System A service life of 100 years for the leachate collection system was assumed for contaminant transport modelling to analyze the performance of the landfill.

The leachate collection system will be monitored by sampling and measuring leachate flows draining from the collection system. Sampling and measurement of leachate flows will be conducted for the duration of the leachate contaminating life span. Headers and collection pipes can be visually inspected using cameras. Manholes will be readily accessible and will be inspected for integrity, presence of debris and leachate flow.

The service life of the underdrain leachate collection system for the West Landfill/Area A and South Landfill/Area B is anticipated to be 100 years as estimated as part of the site-specific design optimization of the existing West and South Landfills discussed previously in Section 7.8. Once the underdrain leachate collection system fails, toe drains will be installed around the perimeters of the waste fill areas. The underdrain leachate collection system is designed to facilitate inspections and maintenance. The underdrain leachate collection system will be operated, inspected, monitored, maintained and repaired as needed for the duration of the leachate contaminating life spans.

The service life of the finger drains was estimated as 30 years (see Sub-Appendix D6-K for calculation sheet). Since operation of the leachate control system at the Old Landfill will be required for the entire contaminating life span of the Old Landfill, the finger drains, perimeter collectors, header pipes and manholes will be operated, inspected, monitored, repaired and/or replaced for the duration of the contaminating life span. Headers and collection pipes can be visually inspected using cameras. Manholes will be readily accessible and will be inspected for integrity, presence of debris and leachate flow. The leachate collection system of the Old Landfill, including finger drains, pipes and manholes can be easily repaired or replaced when required.

Given that the finger drains will be easily accessible for repair or replacement at the end of each 30-year service life cycle, the service life of the finger drains can be considered to exceed the contaminating life span of the landfill.

10.3 Pumping Facilities and Leachate Storage Tanks The leachate pumps and pumping facilities (i.e. pumping houses and pumping stations) will have service lives shorter than the leachate contaminating life span. They were designed to allow access, operation and maintenance activities.

The forcemains will be installed outside the waste fill areas at a depth less than 2 m and for this reason they will be accessed, repaired or replaced as needed during the leachate contaminating life span.

The leachate storage tank is above ground and will be accessed, repaired or replaced as needed during the leachate contaminating life span.

The leachate pumps and pumping facilities will be operated, monitored, maintained, repaired and replaced as needed during the leachate contaminating life span.

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10.4 Perimeter Cut-Off Wall The performance of the existing perimeter cut-off wall around the existing Old Landfill waste fill area will be monitored by the network of shallow monitoring wells and trenches in the weathered till. Sampling from these monitoring wells will indicate the need for replacement of the cut-off wall after the recompacted clay has weathered. Furthermore, in-situ response testing in monitoring wells screened within the cut-off wall can be performed as required to determine the hydraulic conductivity of the recompacted clay. The cut-off walls can be replaced as needed during the contaminating life span through re-excavation and recompaction of the cut-off wall in case weathering renders the wall ineffective in the future. The technology of recompacted clay barriers is straightforward and well established. On this basis, the cut-off wall will function for the duration of the contaminating life span.

The cut-off wall will be left in place after the contaminating life span.

10.5 Recompacted Clay Side Slope Liner The effectiveness of the recompacted clay side slope liners will be monitored through shallow monitoring wells in the weathered till. The side slope liners must prevent the lateral migration of leachate or landfill gas for the contaminating life span of the expansion.

The service life of the side slope liners is expected to exceed the contaminating life span of the landfill as the local clay material used for the liners will not be susceptible to physical/chemical degradation and/or an increase in hydraulic conductivity associated with clay-leachate interactions. Maintenance of the side slope liners will not be possible nor required.

The stable characteristic of the local clay material relates to its clay mineral fraction being comprised mostly of inactive minerals such as illite and chlorite, as inferred by the low Activity (A) values (i.e. Plasticity Index / Percent Clay Size Content) of 0.3 to 0.6 based on a Plasticity Index of 12% to 17% and percent clay size content of 28% to 40%. In comparison, soils containing active clay minerals such as sodium montmorillonite have A values in excess of four (4) (Holtz and Kovacs, 1981) and are more susceptible to physical/chemical changes and hydraulic conductivity increases associated with clay-leachate interactions. Another factor contributing to the stability of the clay liner material is that the divalent cations calcium and magnesium as opposed to the monovalent cation sodium are the dominant exchangeable cations on the clay mineral surfaces (reflecting the abundance of the carbonate minerals calcite and dolomite in the overburden and bedrock). With divalent cations initially on the clay mineral exchange sites, the clay liner fabric is naturally in a flocculated state and hence is less prone to further flocculation and associated increases in pore sizes and hydraulic conductivity.

After the service lives of the underdrain leachate collection systems of the West Landfill/Area A and South Landfill/Area B have expired, a toe drain will be installed and the recompacted clay liner on the below grade side slopes will be functional, limiting the migration of leachate or landfill gas laterally through the shallow weathered zone of the clay till. Therefore, a cut-off wall will not be required around the proposed West Landfill/Area A and South Landfill/Area B waste fill areas.

10.6 Toe Drains Toe drains will be installed at the end of the underdrain leachate collection service life (projected for just above 100 years). Once installed, toe drains will be monitored by sampling and measuring the quantities of leachate flowing from the drains.

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The toe drains can be repaired and/or replaced for the duration of the leachate contaminating life span of the landfill. Sampling and measurement of leachate flows from the drains can be conducted as long as the drains function.

The toe drains will be designed to allow for maintenance for the duration of the remaining contaminating life span of the landfill. Monitoring and maintenance of the toe drains will cease when monitoring indicates that the contaminating life span of the landfills has ended.

10.7 Landfill Gas Collection and Management Facilities As mentioned above, the Landfill Standards (2012) establishes the contaminating life span in the context of landfill gas. The Landfill Standards (2012) considers an unacceptable impact to be the subsurface migration of landfill gas at concentrations in excess of the allowable methane concentrations defined by O.Reg. 232/98 (MOE, 1998):

Less than 2.5 percent methane gas in the subsurface at the property boundary;

Less than 1.0 per cent by volume in any on-site building or enclosed structure, and in the area immediately outside the foundation or basement floor of the building or structure, if the building or structure is accessible to any person or contains electrical equipment or a potential source of ignition, except for leachate or landfill gas facilities that include specific health and safety measures and procedures to control asphyxiation and explosion risks; and

Less than 0.05 percent methane (i.e. not present) in a building, or its foundation, which is located off-site.

The active gas management system will be shut down and decommissioned after landfill gas generation has diminished to a level where emissions to the atmosphere are acceptable or treatment by combustion will not be required/practical. For the purposes of landfill gas subsurface migration, the contaminating life span will end when monitoring confirms that methane gas is not present at locations and concentrations summarized above once the gas management system operation is not required/practical.

The landfill gas collection and management facilities will be easily monitored. Collected gas quality and flows will be monitored. Repairs, replacement and modifications can be undertaken as needed to provide the required service life.

The on-Site receptor buildings such as scale house, offices, maintenance building, and pump houses will continue to be equipped with a methane detection and alarm system. This methane detection and alarm system will be inspected/maintained and remain operational until the on-Site buildings are decommissioned.

10.8 Surface Water Management Facilities Surface water management structures such as perimeter ditches, surface water diversion berms, downchutes, stormwater ponds, flood control berm, on-Site municipal drains and flood control facility will be all above ground and will be accessed, repaired or replaced as needed during the leachate contaminating life span.

11.0 CLIMATE CHANGE CONSIDERATIONS The document entitled “Considering Climate Change in the Environmental Assessment Process” (MOECC, 2017) was used as a guide for incorporating measures in the landfill expansion design that reduce both its impact on climate change (i.e., climate change mitigation) and the impact of climate change on the landfill (i.e., climate change adaptation). These measures are described in the following sections.

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11.1 Greenhouse Gas Mitigation The main Greenhouse Gas (GHG) mitigation component will be the active landfill gas collection and control system. The existing landfill has two flares and is approved for a third flare. The existing landfill gas collection and control system will be expanded to accommodate the proposed landfill expansion, including installation of additional flare capacity over the operational phase of the landfill. The landfill gas collection and flaring operation mitigates a significant amount of GHG because it captures and combusts the collected landfill gas before it can be released to the atmosphere. The landfill gas collection and control system design have flexibility to accommodate future landfill gas utilization if economically viable.

11.2 Climate Change Adaptation The planned 20 year operational period of the landfill expansion will be too short to be significantly affected by climate change. However, during the post-closure period, longer term changes in precipitation and temperature could possibly affect the vegetative cover growth on the closed landfill and/or runoff of surface water from the landfill final cover and the performance of the components that comprise the stormwater management system. For example, an increase in precipitation and/or an increase in storm intensity or duration would increase the amount of runoff, potentially resulting in surface erosion of the vegetated landfill final cover surface and exceedance of the capacity of the stormwater management system.

Climate change adaptation was incorporated in the landfill expansion design in the following ways:

Surface water diversion berms are proposed on the landfill final cover to reduce runoff velocity and minimize erosion;

The proposed perimeter ditches, stormwater ponds and Howard Drain relocation were sized to include an allowance for increased storm intensity associated with climate change. These surface water features were sized to accommodate the storm conditions projected post-2050 at the Ridgetown RCS climate station, which are approximately 15% higher than current storm conditions derived from historical data; and

The side slope stability analyses included in Sub-Appendix D6-A – Geotechnical Assessment Technical Memorandum considered the potential effect of a rapid increase in leachate mound height in the landfill caused by an extreme precipitation event.

In terms of leachate generation and management, a long-term increase in leachate generation may gradually increase since mean precipitation is projected to increase up to 15% in 2050 due to climate change effects. Some of the increased precipitation will become runoff and therefore the leachate generation may gradually increase by a fraction of the 15% mean precipitation increase projected for 2050. As described in Section 7.12.1, the BWTL are projected to have an available treatment capacity of 30% of their current approved treatment capacity available in 2040. This available treatment capacity exceeds the potential gradual leachate generation volume increase related to climate change. The effluent of the BWTL will be monitored as discussed in Section 7.12.1 and any fluctuation in leachate quality related to climate change effects will also be captured by the proposed treated effluent monitoring.

The landfill operations will adapt to climate change affected events as described below:

In case stronger than anticipated winds render the litter control fences inefficient, higher or longer litter control fences can be installed; and

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Extreme heat and cold will require staff working outdoors to use applicable standard operational procedures prepared and updated periodically to reflect changing conditions. It is noted that landfill vehicles and equipment will continue to have heaters and air conditioners to provide climate controlled conditions for outdoors staff.

12.0 LANDFILL DEVELOPMENT The expansion of the Ridge Landfill involves the expansion of three existing waste fill areas: the vertical expansion and East Infill within the approved waste fill area of the Old Landfill, the lateral expansion of the West Landfill (Area A) and the lateral and minor vertical expansion of the South Landfill (Area B).

12.1 Landfill Expansion Phasing Plan The existing Ridge Landfill is expected to reach capacity in March 2021. The first cell of the proposed landfill expansion needs to be constructed so that it is available to receive waste when the currently approved landfill capacity is reached. The first area of expansion will be the Old Landfill area because its design will allow:

Shorter construction duration;

Suitability for winter construction; and

Suitability for construction in phases to allow earlier waste filling operations while a portion of the cell expansion is still being constructed.

Area B will be filled next as it will be closer to the Old Landfill area and hence will allow a shorter haul distance of cell excavation spoil to the Old Landfill for use as landfill cover. Area A will be the last area of the proposed landfill expansion to be constructed and filled.

Drawings 5 to 8 show the proposed filling sequence, assuming a waste filling rate of 1.3 million tonnes per year and an apparent waste density of 900 kg/m3. In addition to cell construction, various supporting structures such as landfill gas system expansion, stormwater ponds, screening berms, municipal drains and leachate management facilities will be constructed or existing components modified as part of the landfill development sequence. Table 12.1 provides an estimated construction and operation timeline for cells, stormwater ponds and other key supporting infrastructure.

Table 12.1: Estimated Construction and Operation Timeline

Year Number

Sequencing Year Cell

Construction ID Cell

Operation ID

Expansion/ Construction of Stormwater

Ponds ID

Construction of Other Key Supporting Infrastructure

0 2021 O1 1, 2 and 5

1 2022 O1

2 2023 O2/East Infill O1 LFG collection system expansion

3 2024 O3 O2/East Infill LFG collection system expansion

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Year Number

Sequencing Year Cell

Construction ID Cell

Operation ID

Expansion/ Construction of Stormwater

Ponds ID

Construction of Other Key Supporting Infrastructure

4 2025 O4 O3/East Infill LFG collection system expansion

5 2026 O4 LFG collection system expansion

6 2027 B1 O4 6 LFG collection system expansion

7 2028 B2 B1 7 Howard Drain relocation, flood control facility expansion, LFG system expansion

8 2029 B3 B2

LFG collection system expansion

9 2030 B3


10 2031 B3


11 2032 A1 Above Elevation 225 mASL

4 LFG collection system expansion

12 2033 A2 A1 LFG collection system expansion



15 2036 A4 LFG collection system expansion


17 2038 A5 Above Elevation 225 mASL




20 2041 Above Elevation 225 mASL


Cell O1 will be constructed in late 2020 and early 2021 to allow operations continuity. The proposed screening berms will be progressively constructed as the landfill expansion progresses.

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The landfill gas collection system will be progressively expanded as waste is placed and cells reach final grades. In addition, the landfill gas collection system will be expanded as needed to areas filled with new waste that become inactive for more than six months. The first expansion of the landfill gas collection system will likely start in year 2 (2023) in completed areas within the Old Landfill. Additional flares (not specifically shown in Table 12.1) to combust landfill gas will be installed as the landfill gas flow increases and constructed flaring capacity is fully utilized.

Roads, surface water diversion berms and other structures mentioned in this Report but not specifically discussed in this Section will be progressively constructed over the operating period or completed as part of the closure of the expansion areas.

13.0 LANDFILL OPERATIONS 13.1 Hours of Operation The Ridge Landfill will be open to receive waste from Monday to Saturday, 7:00 a.m. to 5:00 p.m.

The Site will be closed on Sundays. The Site will be open on statutory holidays to honour municipal collection contracts and private sector contracts. If the quantities of waste are sufficiently low, the hours of operation may be reduced.

Equipment hours of operation extend beyond the hours that the Site will be open to the public to allow for preparation and soil covering activities. The hours of equipment operation will be Monday to Saturday, 6:30 a.m. to 6:00 p.m.

Before opening, staff will prepare for the arrival of waste by starting up the weigh scale systems, moving equipment to the working face, and preparing roads for traffic (i.e., snow ploughing or grading). After closing the Site to the public, waste compaction and daily and intermediate soil covering will be completed before moving equipment back to the maintenance compound.

While it is proposed to maintain this schedule on a routine basis, the landfill operator may wish to make periodic revisions to these operating hours. The public will be informed in advance of such changes through the Ridge Landfill Liaison Committee.

There may also be a need to open the Site in an emergency. In such a case, the MECP will be notified. Local residents, as identified by the Ridge Liaison Committee, will also be notified.

With the approval of the District Manager and the Municipal Chief Administrative Officer, or designate, the waste may be received between 5:00 p.m. and 7:00 p.m. to accommodate seasonal or unusual demand.

13.2 Site Equipment The following key equipment are currently available on-Site. The list of equipment will change from time to time to accommodate seasonal/operational/construction needs.

Landfill Compactors;

Dozers;

Articulated Dump Trucks;

Hydraulic Excavators;

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Backhoe;

Road Grader;

Loader; and

Water Wagons.

Landfill vehicles and equipment have heaters and air conditioners to provide suitable working conditions for outdoors staff.

All equipment will be maintained on a regular basis according to the manufacturer’s recommended maintenance schedule.

The above landfill equipment will be used for the following tasks:

waste compaction;

spreading and covering of waste;

excavation, transport, and placement of cover soils or alternative daily cover;

Site grading;

spreading final cover;

general Site maintenance;

temporary or gravel haul road construction and maintenance;

excavation of drainage ditches and stormwater ponds; and

dust control.

Equipment may be replaced by similar capacity in the future as they become older. Based on equipment maintenance schedules and seasonal variations in Site operation, the Owner may add or remove equipment from service at the Site. Pick-up trucks are also required for staff and general maintenance.

Some on-Site construction activities may be contracted out. The equipment fleets will vary according to the construction effort required and the schedule imposed on the Contractor.

13.3 Landfill Staff Landfill staff includes a District Manager, supervisors, scale attendants, equipment operators, gas management operator, office administrative staff and any additional staff as required.

There is at least one operator on-Site at the landfill during operational hours. Staffing levels may change throughout the year to accommodate seasonal changes in Site operation.

During Site operational hours, the scale attendant will verify the source of the waste, the nature and acceptability of the waste, confirm the waste will be properly weighed, issue scale tickets, and collect the associated tipping fees. The scale attendant will then direct the vehicles to the appropriate location to unload waste and/or recyclables.

The landfill operators perform various operational duties such as monitor and direct waste placement in the active landfilling area, compact waste, place cover materials, carry out control measures for dust, litter, noise and odour, ditch cleaning, road grading and other activities as required.

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Repairs to landfill equipment will be performed by the heavy equipment mechanics and their assistants.

Actual manpower may vary and will be dependent on the actual waste quantities received to accommodate seasonal fluctuations. The number of staff also varies depending on personnel arrangements for overtime and part-time staff.

13.3.1 Training Program According to the approved ECA, Waste Connections will develop and implement a training plan for all employees that operate any aspect of the Site. Only trained staff that has the following training as a minimum will operate the Site:

The relevant waste management legislation including EPA, O. Reg. 347 and O. Reg. 232/98 (MOE, 1998), regulations and guidelines;

Major environmental and occupational health and safety concerns pertaining to the waste to be handled, including extreme heat and cold conditions;

The proper handling of wastes;

The management procedures including the use and operation of equipment for the processes and wastes to be handled;

The emergency response procedures;

The specific written procedures for the control of nuisance conditions;

Identifying on-Site activities that have the potential to generate dust;

Identifying how staff will monitor weather conditions and adjust Site operations as required;

The terms, conditions and operating requirements of this ECA; and

Proper inspection, receiving and recording procedures and the activities to be undertaken during and after a load rejection.

In addition, On-site personnel will receive species at risk training prior to the commencement of construction activities and a Contractor Information Manual will be prepared documenting the various species at risk with the potential to be encountered during construction activities.

Waste Connections will keep the training plan and maintain records of staff training at the Site.

13.4 Landfilling Operations 13.4.1 Normal Waste Landfilling Operations The currently approved daily maximum fill rate is 6,661 tonnes per day and the annual maximum fill rate is 1,300,000 tonnes per year, including approved alternative daily cover. This filling rate will apply to any proposed expansion area.

Initially, after a new cell has been constructed, waste will be placed carefully in a thin layer over the entire area of the cell in order to avoid damage to the leachate collection system due to equipment travel and frost.

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Normal daily landfilling operations (as described below) will take place once the first layer of waste is placed. The landfill will be constructed in lifts of approximately 5 m thick. This will establish the height of the working face. To achieve a high level of compaction of the waste, the working face will be sloped at 5(H):1(V).

Waste haul vehicles (packer trucks, roll-off trucks, trailers, etc.) will travel to the working face via access roads. Operations supervisors oversee traffic control responsibilities, assign tipping locations, maintain a small and orderly working face, and promote safety. Waste will be either tipped using the power of the vehicle/trailer itself (e.g. walking floor trailers, roll-off and front-end trucks etc.) or by using stationary tippers to unload transfer trailers.

Waste will be deposited from waste vehicles or tippers at the base of the working face and spread over the working face by bulldozers and landfill compactors. The waste will then be compacted by several passes of the compactors.

The width of the working face will depend on the number of vehicles that will be unloading waste at any given time. The width will be large enough to allow several vehicles to unload side by side, separated by sufficient space in between for safety reasons. Working areas for landfill equipment will be required at the bottom and top of the working face for unloading and manoeuvring of landfill equipment. Currently, an estimated maximum working face width of 70 m and a working area length of 100 m is utilized which results in an active area of the working face of approximately 7,000 m2.

Maintaining the working face to a minimum size will make the fill area operations more efficient and will provide aesthetic and environmental benefits as follows:

Minimize the amount of wind-blown litter that might occur;

Manage and control working face operations in a safe and efficient manner;

Efficient use of soil or approved alternative daily cover resources; and

A neat, organized and tidy site appearance.

13.4.2 Daily, Intermediate and Final Cover Placement The working face will continue to be covered with clean cover soil or alternative daily cover at the end of each operating day.

The native soil from cell excavations or stockpiles will also be used as intermediate or final cover. Cover soil will either be obtained directly from the excavation or from one of the on-Site soil stockpiles. The following procedure for the application of cover material will continue to be used:

1) Daily Cover: At the end of each working day, the entire working face will be graded smooth and compacted. A minimum 150 mm thick layer of daily cover material will be placed on all exposed waste at the working face. The following alternative daily covers are currently approved: clean soil, non-hazardous contaminated soils, tarpaulins, blown straw, shredded tires, dewatered sewage biosolids and non-hazardous auto-shredder waste. Any approved alternative daily covers used will be monitored to ensure that no adverse environmental effects are caused. In the event that an adverse effect is caused, the alternative daily cover will be temporarily discontinued and another approved cover will be used. The use of temporarily discontinued alternative daily cover will be resumed when measures are in place to effectively control adverse effects (e.g., litter, odour and dust impacts) as confirmed by site inspections completed by the Landfill Manager;

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2) Intermediate Cover: A 300 mm thick layer (minimum) of intermediate cover soil will be applied in areas where landfilling will be temporarily discontinued for six months or more. This will facilitate the movement of equipment and prevent the erosion of cover and exposure of waste. For example, intermediate cover will be placed on the top of each 5 m lift of waste and also on any interior waste slopes which will not be disturbed until the next landfilling stage. These areas will be seeded as soon as practical; and

3) Final Cover: The final cover for the proposed expansion areas consist of 0.15 m of topsoil overlying 0.85 m of un-compacted soils. Soil used to construct the final cover will be obtained from cell excavations or the on-Site soil stockpile. The topsoil material will be sourced from the on-Site topsoil stockpiles. This thickness of cover over the waste will be necessary to facilitate the growth of vegetation, which will be applied by hydro-seeding and mulching. It will also assist in limiting air intrusion from active gas collection areas. Within one year of any portion of the Site being filled to its final elevations, final cover will be placed over that portion of the Site.

Dewatered sewage biosolids may be used as daily cover. Off-Site odour impacts will be monitored and in the event that any impacts occur, an odour management plan will be immediately implemented. If any adverse effect is caused by the use of sewage biosolids, the Owner will immediately stop the use of such material and resume the use of other approved cover or clean soil. Detailed records of the locations where the material has been applied and the quantities of the material will be kept on-Site. These records will be kept for a minimum of five years following the closure of the Site.

Because of the low permeability of the native clayey soil, there will be a tendency for the horizontal layers of cover soil to interrupt the downward percolation of infiltrating precipitation. If these cover layers redirect the drainage laterally, leachate seeps may occur on the above-ground side slopes of the landfill. To prevent this from occurring, horizontal surfaces of daily and intermediate soil cover will be stripped (or scarified as a minimum) before subsequent landfilling occurs to remove or disturb the cover soils. This will ensure that a hydraulic connection will be established through the entire waste mass. This is particularly important on the 4(H):1(V) side slopes.

If suspect, contaminated soils to be imported and used as daily cover will be tested for Toxicity Characteristic Leaching Procedure (TCLP) and classified as non-hazardous when compared to O.Reg. 558/00 standards. Consideration will be given to the MECP document “Management of Excess Soil – A Guide for Best Management Practices” (2014) when assessing and importing contaminated soil.

13.4.3 Initial Lift Landfilling Operations The first waste lift in each new expansion cell will be placed in a thin layer over the entire area to avoid damage to the leachate collection system due to equipment travel and frost. A minimum 1.5 m lift thickness of waste will be required in the first layer. The waste will initially be dumped near the perimeter of the fill area and pushed out over the exposed leachate collection system. The landfilled waste will act as a travelling surface for equipment and waste haul trucks.

13.5 Surface Water Management Section 6.0 of this report describes the design of the surface water management system.

Surface runoff from the Ridge Landfill will be managed by two main drainage collection systems:

Perimeter drainage ditches near the toe of the landfill side slopes; and

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Municipal drains.

All surface water from the completed, final covered slopes of the landfill areas will flow into perimeter ditches which will be located between the toe of the landfill side slopes and the perimeter roads. This ditch system was designed to convey stormwater runoff from the landfill to the on-Site stormwater ponds (see Drawing 22). The proposed perimeter ditch design involves either:

A triangular v-shaped grass covered channel with 3(H):1(V) side slopes at a typical depth of 1.2 m and an approximate slope of 0.5%; or

A grass covered trapezoidal channel with 3(H):1(V) side slopes at a typical depth of 1.2 m, a 1.5 m wide flat bottom and an approximate slope of 0.2%.

The stormwater ponds will continue to be operated in batch mode. Water quality will be tested according to the monitoring program presented in Section 15.2.2.2 before water is released from the stormwater ponds to the municipal drains or flood control facility. If the discharge objectives are exceeded, a contingency plan will be implemented (see Section 17.2).

One of the objectives of the surface water management system is to separate any contaminated or potentially contaminated runoff from non-contact (uncontaminated) runoff and manage it as leachate.

Construction of the proposed expansion cells are planned to take place in stages. The staged approach will result in one stage being landfilled while an adjacent stage is under construction. To further facilitate separation of uncontaminated runoff, a temporary berm will be constructed in the cell excavation paralleling the uncompleted end(s) of the leachate collection system between stages. Along the berm, at the toe of uncompleted slopes, there will be a ditch to convey runoff toward an inlet to the leachate collection system. Uncontaminated runoff from the excavation will collect against this berm and will be allowed to evaporate or will be pumped into the municipal drains. This water will include groundwater seepage from the excavation. The berm will be removed and relocated as construction of the leachate collection system advances.

In addition, surface water impacts may be minimized by prohibiting the use of road salt on on-Site roads and excessive solids accumulation in the stormwater ponds will be removed as needed.

13.6 Leachate Management The leachate management system is described in detail in Section 7.0 of this report.

Leachate produced at the approved waste fill areas and proposed expansion waste fill areas will be pumped to the leachate storage tank through on-Site forcemains. From the leachate storage tank, leachate will be discharged through forcemain for treatment at the BWTL.

Leachate collection pipes and manholes will be video inspected and cleaned annually for the first five (5) years after placement of waste over the top of each pipe. This frequency may be reduced to once every two (2) years on the basis of inspection results with the approval of the Regional Director. The inspection and maintenance records will be reviewed by the consultant that prepares the Annual Site Development, Operations and Monitoring Report.

The leachate management infrastructure, including pumps and leachate storage tank, will be inspected and maintained as per manufacturer’s recommendations. Spare submersible riser pumps will be available on-Site for immediate replacement to maximize leachate removal in case of pump failure.

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Sludge will not be deposited in the waste fill zone in a manner that would allow it to move into the leachate collection system and promote biological clogging. See procedures above for the first lifts following construction of new leachate collection system.

13.7 Landfill Gas Management The landfill gas collection system and gas management facility are described in detail in Section 8.0.

LFG collection will be optimized through a procedure of balancing and maximizing the vacuum (or negative pressure) within the system.

Balancing of the gas extraction system will be performed on a periodic basis. The tests performed to balance the collection system are:

Methane, oxygen and balance gases concentration at each well;

Vacuum at each well; and

Gas temperature at each well.

Methane and oxygen concentration measurement at a well will be the primary test for determining if the applied vacuum will be changed.

The measurement of vacuum will be conducted to establish a relationship between methane and oxygen concentration and flow rate at each well. Once a relationship is determined, an optimal flow rate and vacuum can be established for each well. The goal is to maximize gas extraction and minimize air intrusion.

The amount of vacuum required to extract gas will vary at each well and with time.

Measurement of gas temperature at each well can reduce the potential for development of landfill fires. High gas temperature at a well can be indicative of excessive air intrusion. It is important to establish a normal temperature for each well.

Landfill gas parameters will be monitored at the flares and blowers monthly. Gas flow rates going into the flare will be measured by means of a sensor in the line between the blower building and flare. The flare system will be equipped with thermocouples located at the top of the flare stack to monitor and control combustion temperature.

13.7.1 Operation and Maintenance The blower/flare station will be properly operated and maintained at all times. All operating procedures and maintenance program are outlined in a manual that will be updated as necessary. At a minimum the following information will be found within the manual:

Routine operating and maintenance procedures in accordance with sound engineering practices and as recommended by the equipment and the blower/flare station manufacturers;

Calibration procedures of the blower/flare station;

Emergency procedures and procedures to prevent upset conditions;

Procedures to record the date and time when each of the flares is operated and the procedures to monitor and record the quality;

Procedures for any record keeping activities relating to operation, maintenance and repair of the equipment;

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Procedures to record process upsets/upset conditions and the remedial actions taken to respond to the upsets;

All appropriate measures to minimize noise and odorous emissions from all potential sources; and

Procedures for recording and responding to complaints regarding the operation of the equipment.

The procedures, measures and recommendations found within the manual will be implemented.

For a minimum of two years from the date of their creation all records and information related to or resulting from the recording activities of the Air ECA will be retained and available to MECP staff upon request. The following information will be retained:

All records on the maintenance, repair and inspection of the equipment and the blower/flare station;

All records produced by the blower/flare station;

All records on the operation of the equipment;

All records generated in the acoustic audit measurements;

All records of process upsets/upset conditions and remedial actions taken to respond to the upsets; and

All records of any environmental complaints; including:

i) A description, time and date of each incident to which the complaint relates;

ii) Wind direction at the time of the incident to which the complaint relates; and

iii) A description of the measures taken to address the cause of the incident to which the complaint relates and to prevent a similar occurrence in the future.

Each environmental complaint must be provided to the MECP within two (2) business days of the complaint and will include the Air ECA number, description of the nature of the complaint, the time and date of the incident and a description of the measures taken to address the cause and to prevent a similar occurrence in the future.

14.0 SITE CONTROL AND MAINTENANCE 14.1 Access and On-Site Traffic Control Regular access to the Site is from the main Site entrance, off Erieau Road. Waste haul trucks, staff and visitors will be required to use this access point. From the Site entrance, the landfill access road allows access to the waste fill areas and all other facilities on-Site.

Lockable gates have been installed across the access road entrance. The gates prevent trespassing when the Site is closed and will be locked at the end of each day of operation. The Site is deemed to be closed when a Site supervisor is not present at the Site and the Site entrance and exit gates will be locked or otherwise secured against access by unauthorized persons.

Signs are posted at the Site entrance and exit displaying the following information, which should be legible from a distance of 25 m:

Name of Site;

Name of the operator;

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Environmental Compliance Approval number;

Telephone number to which complaints may be directed;

24-hour Emergency/after-hours telephone number(s); and

Normal hours of operation.

A sign also displays the Site rules. The rules include but are not necessarily limited to:

All trucks must be covered to prevent the escape of waste;

No trespassing;

No scavenging;

No burning of waste;

No illegal dumping by the side of roads;

Maximum speed will be 20 km/h on unpaved on-Site roads and 40 km/h on paved on-Site roads; and

Allowable and prohibited waste types.

When the Site is operating, all incoming waste haul vehicles are required to report to the scale house to be weighed before proceeding to the landfill working area. Visitors must report to the administration building and fill out the visitor's log.

Sufficient space is provided for the queuing of vehicles behind the weigh scale such that long queues will not back out onto Erieau Road. Visitors reporting to the administration building may bypass the scale once they reach the scale area.

Signs will be posted along roads to provide direction to the current working area. Signs will be posted at Site facilities to warn of potential hazards and areas of restricted access. Interior roads will be clearly marked with standard highway signs showing speed limits, curves, intersections, direction of travel, and other points of caution or danger.

To further prevent unauthorized entry of vehicles, the Site will be enclosed with a fence or berms around the perimeter of Ridge Landfill property. All gates on the perimeter fencing will have locks to prevent unauthorized entry.

14.2 Waste Control Every waste truck stops at the weigh scale to be surveyed by the scale operator. The information that will be obtained from the driver is listed in Section 15.1.3.

Signs will be posted listing the allowable and prohibited waste types:

Permitted wastes: solid, non-hazardous residential, institutional, commercial, and industrial wastes; and

Prohibited wastes: liquid and hazardous. Additional prohibited wastes will be determined by Waste Connections and posted outside the main entrance.

Incoming wastes will be subject to checking by the scale house personnel. If a load is considered "unacceptable," (i.e., waste type or materials not identified on the ECA), the weigh scale operator will have the authority to reject the load.

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Another opportunity for waste control will be at the working area. If an operator identifies "unacceptable" waste when a vehicle is unloading, it will be reloaded back into the source vehicle for removal. If the source vehicle has left the Site, the waste will be removed by a front-end loader and placed aside near the working face. The hauler and generator will be identified, if possible, and the hauler will be asked to remove the waste promptly.

Materials rejected from the landfill will be reported at the required frequency to the local MECP District Office. Records of rejected waste and material removed from the Site are maintained at the Site office.

Scale personnel and equipment operators will be trained to recognize non-permitted wastes. If an operator uncovers suspect waste when moving dumped material in the working area, all work of compacting or covering will cease until the material is set aside so that further action can be taken.

To further discourage attempts at disposal of unacceptable or hazardous materials, it may be necessary to conduct random checks of incoming waste loads. Selected vehicles will be directed to a designated area within the working area to unload. The waste will then be inspected for the presence of hazardous or unacceptable materials. Materials not approved for Site disposal will be segregated and handled as needed and required by applicable Regulations.

14.3 Litter Control Litter will be controlled at the Ridge landfill using a variety of measures. The following preventative litter control measures will continue to be undertaken at the Site:

Daily application of daily cover material to the working face of the landfill;

Portable litter fences downwind from the working face will be used at the active working face. The portable litter fences will be as close to the working face as possible and will be moved on a daily basis to remain downwind of the working face;

When practical, maintain a working face shielded from the wind to be used on days with strong winds;

Permanent litter fencing installed at the perimeter roads or other strategic locations;

Minimizing the size of the active working face to reduce litter generation;

During higher wind speeds events, the compactors will be monitored for their ability to compact waste immediately after unloading to immobilize litter. If delays are significant enough to allow considerable amounts of litter to be mobilized, an extra compactor will be brought to the working face to compact the fresh waste more rapidly; and

Vehicles transporting waste will be tarped, if required, to prevent litter from blowing out of the vehicle.

Landfill staff will pick up litter from around the Site whenever required as a result of specific events such as high winds. Litter will be collected from the spaces between and outside of the litter fences and disposed of at the working face. Litter pick-up on adjacent properties will be undertaken as required, and where the property owner or tenant permits access.

As described in Section 11.0 (Climate Change), in case stronger than anticipated winds render the litter control fencing inefficient due to frequent extreme weather events, higher and/or longer litter control fences will be installed.

Complaints regarding litter will be dealt with according to procedures described in Section 15.3.

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14.4 Odour Control Landfill odours may originate from exposed waste at the working face, or landfill leachate. This odour is generally regarded as unpleasant and it may, in some instances, cause an off-property nuisance. In an effort to reduce the potential for odour emissions and off-property impacts, the following best management practices will be implemented:

Regular inspection of the landfill for leachate outbreaks will be carried out and any required cover repairs will be carried out;

Waste compaction and the application of daily cover;

Minimize the size of the working face; and

If an odour complaint is made, efforts will be made to immediately identify the problem and apply mitigative measures to control the odour.

Municipal sewage sludge is expected to be the waste with strongest odour received at the Ridge Landfill. Sludge or other wastes with very strong odours will be placed at the toe of the working face and will be immediately covered with other garbage or daily cover.

Odours may originate from cracks or fissures in the soil cover well after landfilling has taken place. Regular inspections will identify any cracks or fissures that must be repaired by filling with cover soil.

Landfill gas produced from the decomposition of waste includes a small fraction of malodorous compounds. Depending on the weather conditions, these may create an odour problem if the landfill gases are being released from the Site in sufficient quantities. The gas management system wherein landfill gas is collected and flared is discussed in Section 8.0. This reduces uncontrolled gas emissions from the landfill and, through flaring, destroys the odour causing compounds. If odours become a problem in unfinished areas of the landfill, temporary horizontal collectors could be installed to control odours until the area achieves final grade and permanent vertical wells are installed.

Odour problems from leachate can occur where it is exposed to the atmosphere in manholes, pumping stations or treatment facilities. Leachate may also be exposed to the atmosphere if leachate seeps develop. Leachate will be collected, stored in the leachate storage tank and pumped through the municipal sewage forcemain for treatment. Since all potentially odorous leachate management components are buried or enclosed, significant leachate related odours are not an issue. Leachate manholes, wet wells, riser pipes, and cleanouts will be sealed. Any leachate seeps will be promptly repaired, not only to prevent odours, but to prevent surface water contamination.

If required, odour suppressing agents will be used as an additional measure against odour problems. An odour supressing misting system is currently being used at the Ridge Landfill to manage odours emissions. This system operates year-round as it runs with summer and winter grade biodegradable liquid products.

The Site will maintain a log to record the date, time, wind direction and description details for any odour complaints. This log will also describe activities related to the investigation of the complaint, and also record the mitigating measures implemented to address concerns. Once a complaint is notified, appropriate steps to determine the possible causes of the complaint will be taken, and necessary actions to eliminate the cause of the complaint will be undertaken.

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Regular Site inspections will include qualitative assessment of on-Site odours. Should odour emissions with potential to migrate off-Site be identified, the source will be identified, documented, and appropriate corrective action will be implemented as required. Any complaints regarding odour will be noted and receive a prompt response. These will be recorded, along with the mitigating measures taken, and reported in the Annual Report submitted to the local MECP District Office.

The complaint response procedure is described in Section 15.3.

14.5 Dust Control The main source of dust will be on-Site access roads, particularly if unpaved, and from equipment movement around the landfill working area. To minimize the potential for on-Site and off-Site impacts due to dust, the following best management practices will be implemented at the Site:

The main on-Site haul road will be paved to reduce dust emissions and minimize tracking of soil onto off-Site roadways;

To avoid excessive dust generation, on-Site roads will be routinely maintained as part of the normal Site operations;

▪ Roads will be swept and watered to control dust as needed using available on-Site equipment such as water truck, loader with attachments, and backhoe with attachments;

▪ During dry periods, a water wagon will be deployed to apply water for dust suppression as required on unpaved roads. Calcium chloride, sodium chloride or oil will not be used for dust control within the Site area because the chemicals could affect groundwater or surface water quality. Other MECP approved dust suppressants could be used, when required;

The site perimeter roads will be maintained on a regular basis by grading. Road crowns and slopes will be graded and maintained as needed;

A speed limit of 20 km per hour on unpaved roads and 40 km/h on paved roads will be enforced to avoid excessive amounts of airborne dust. These speed limits will be posted on-Site and communicated to vehicles entering the Site by the scale house attendant;

Travel on areas of undisturbed soil will be minimized, where possible, and exposed soil areas seeded as quickly as possible; and

A truck wheel cleaning facility will be available on-Site. Trucks have the wheels cleaned before leaving the Site for increased mud and dust control.

Training for Site personnel regarding these control measures will be completed on an as-needed basis.

The Site will maintain a log to record the date, time, wind direction and description details for any fugitive dust complaints. This log will describe activities related to the investigation of the complaint, and also record the mitigating measures implemented to address concerns.

Regular Site inspections will include assessment of dust conditions at the Site (including a visual assessment of the dust sources) to determine if the control measures described above will be implemented on that day. As well, the inspection will include a qualitative assessment of any odours.

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Any deficiencies that these inspections reveal will be corrected and a written record of the inspections will be kept. This will allow for the effectiveness of control measures to be reviewed on a regular basis.

14.6 Bird and Non-Bird Vector Control Animals may be attracted to a landfill or waste processing site because it provides a suitable foraging habitat. Consequently, they could move onto the landfill or into a facility temporarily or permanently.

If required, vermin will be controlled at the landfill or diversion facilities by trapping or retaining a pest management company.

Birds such as gulls may become a nuisance by attending the site and adjacent or nearby properties, creating noise and fouling those lands. Another concern regarding birds congregating at landfills is the hazard they may create to aircraft. Considering the location of the existing Chatham Airport and the patterns of local air traffic, bird control is very important for the Ridge Landfill operations. The Ridge Landfill operates a bird control program to manage and potentially reduce on-Site birds. The bird control program will be modified or upgraded as needed to manage and potentially reduce residual bird hazard to aircraft safety. The Ridge Landfill managers will coordinate the on-Site bird control operations and activities with the Chatham Airport.

Specific control measures for bird and non-bird vector control include but are not limited to:

Daily cover of waste;

Minimize size of working face;

Minimize areas of bare ground;

Encourage growth of tall grass (discourage loafing);

Vegetated banks at the stormwater ponds;

Use of pyrotechnics, birds of prey, distress calls, models, kites or other options available to control birds; and

When and if required, implement the use of scare pistols (e.g., bangers and crackers) to discourage gulls at the active faces, overhead, and in loafing areas2.

14.7 Fire Control 14.7.1 General Small localized fires will be dealt with, if possible, using fire extinguishers to be located throughout the on-Site buildings and on heavy equipment units. The area of the fire will be evacuated and the Fire and Emergency Services will be called (9-1-1) to provide advice or to perform follow up inspections.

In cases involving a larger fire or explosion, staff will evacuate the area and will direct all residents and vehicles to leave the Site and assemble in a location away from the danger area. Emergency Services will assume situation control and direct other staff.

In all cases, the MECP will be notified of fires / explosions and an incident report will be completed.

2 LGL Limited, Ridge Landfill Expansion – Assessment of Potential Bird Hazards to Aircraft Safety, May 2019 (Appendix D4 Ridge LF EA)

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14.7.2 Landfill Fires and Explosions The following three elements are required for a fire to exist: (i) fuel source, (ii) ignition source (flame, heat or spark), and (iii) oxygen (air). Removal of one of these elements will assist in the control of a fire.

Smoking and open flames will not be allowed on-Site, except in pre-designated areas. Catalytic converters on the underside of vehicles are sufficiently hot to ignite dry materials such as grass. Vehicles will not be left running in a stationary position over dry grass or other combustible materials for extended periods of time.

Dry chemical fire extinguishers are effective for surface fires involving ordinary combustibles such as wood, grass, flammable liquids, and electrical equipment. These fire extinguishers are appropriate for small, localized fires such as a drum of burning refuse, a small burning gasoline spill, a vehicle engine fire, etc. No attempt will be made to use these extinguishers for well-established fires or large areas or volumes of flammable liquids. In case of larger fires, the work area will be evacuated immediately and the fire department called.

In the event of surface fire or explosion:

Call the local fire department;

If the situation can be readily controlled with available resources without jeopardizing the health and safety of Site workers, take immediate action by;

▪ Standing or operating equipment upwind from the fire; ▪ Using fire extinguishers; and, ▪ Covering the area(s) with soil.

If the fire cannot be controlled, as specified above:

▪ If possible, isolate the fire to prevent spreading; ▪ Clear the area of all personnel working in the immediate vicinity; and, ▪ Immediately notify Site and emergency personnel and the fire department.

Subsurface fires may occur when air is excessively drawn into the landfill by the landfill gas collection system, thus providing the oxygen for combustion. When operating the gas collection system, care must be taken not to draw air into the landfill through the cover or the various engineered features, such as leachate riser pipes.

In the event of a subsurface fire, landfill operations staff will:

Call the local fire department;

Do not attempt to fight a subsurface fire without the direction of the local fire department;

Stand or operate equipment upwind from the fire, if there is any potential for smoke inhalation;

Be aware that a subsurface fire could develop a subsurface void and that the ground surface of the affected area may not support personnel or equipment; and

Limit oxygen to a subsurface fire by placing clean soil material over the affected areas (i.e., smothering the fire). Surface discoloration, surface heat, smoke, “steam” vapour, instantaneous waste settlement or voids are typical indicators of a subsurface fire location. Excavation into the waste will not be carried out as this would expose the affected areas to additional oxygen.

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14.8 Site Inspection and Maintenance 14.8.1 Inspection Waste Connections maintains a proactive inspection program covering events that could potentially lead to nuisances or environmental concerns such as litter, mud, dust, odour, seeps, general Site appearance, etc. Daily, weekly and monthly inspections will be completed for the Site and the properties in the immediate vicinity and findings will be documented. The records of Site inspections will be retained on-Site for a minimum of two years as required by the ECA. Any deficiencies or deviations noted from the approved operations plan will be addressed promptly. Operations/maintenance observations will be made daily in the course of routine operations and specific inspection items for the landfill operator/Site attendant will include the following information:

Name and signature of person that conducted the inspection;

Date and time of the inspection;

The list of any deficiencies discovered;

The recommendations for remedial action; and

The date, time and description of actions taken.

A record will be kept in the daily log book for the following items:

The type, time of arrival, hauler name, and quantity (tonnes) of all waste including approved cover material received at the Site;

All complaints from the public received and an indication of the action taken in response;

Results of any tests done to determine acceptability of waste at the Site;

A list of the refusal of waste shipments, the reason(s) for refusal and the origin of the waste, if known;

Calculation of the total quantity (by weight) of waste received at the Site for each day;

A record of litter pickup activities as required; and

Site inspections.

The Site will be inspected weekly for the following items:

Conditions of roads (including signs, gates, and fences)

▪ Surface condition (pavement or gravel); ▪ Presence of litter; ▪ Dust accumulation (on paved areas); ▪ Sufficient moisture for dust control (on unpaved roads); ▪ Need for ploughing in winter; and ▪ Traffic congestion and queuing.

Condition of drainage works (ditches, culverts, berms, ponds).

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▪ Erosion; ▪ Siltation; and ▪ Clogging.

Condition of final cover.

▪ Erosion; ▪ Settlement; ▪ Ponding of runoff; ▪ Development of cracks or fissures; ▪ Vegetation failure; and ▪ Leachate seeps.

Condition of working area (including litter fences).

▪ Minimized working face size; ▪ Presence of litter; ▪ Sufficient daily cover application; ▪ Efficiency of equipment; ▪ Sufficient moisture for dust control; ▪ Development of cracks, fissures or leachate seeps; ▪ Presence of birds and vectors; ▪ Condition of equipment (e.g., functioning mufflers); and ▪ Traffic congestion and queuing.

Condition of scales, maintenance and administration buildings and any other buildings on-Site.

Condition of excavated areas and leachate collection systems.

▪ Erosion of slopes; ▪ Ponding of water; ▪ Contact of contaminated runoff with other surface runoff; and ▪ Exposure of or damage to the leachate collection layer.

Condition of buffer areas surrounding the Site (also stockpiles).

▪ Condition of perimeter fencing; ▪ Presence of litter; ▪ Vegetation failure; and ▪ Odour or dust.

Condition of wildlife exclusionary fencing during construction.

Condition of erosion and sediment control measures during construction.

The Site will be inspected monthly for the following items:

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General settlement areas or depressions on the waste mound;

Shear and tension cracks on the waste mound;

Condition of surface water drainage works;

Erosion and sedimentation and associated control measures in surface water drainage system;

Presence of any ponded water on the waste mound;

Adequacy of cover material;

Evidence of vegetative stress, distressed poplars or side slope plantings on or adjacent to the waste mound;

Condition of groundwater monitoring wells and gas wells;

Presence of insects, vermin, rodents and scavenging animals on or adjacent to the waste mound;

Condition of fence surrounding the Site; and

General Site appearance.

Monthly site inspection records in the form of a written log or a dedicated electronic file will be retained on-site until they are included in the annual report. As a minimum they will include the following information:

A summary of wastes received and wasted for disposal at the Site;

The area of the Site in which waste disposal operations are taking place;

A calculation of the total quantity (tonnes) of waste received at the Site during each operating day and each operating week;

The amount of any leachate removed, or treated and discharged from the Site;

A record of litter collection activities and the application of any dust suppressants;

A record of the daily inspections;

A description of any out-of-service period of any control, treatment, disposal or monitoring facilities, the reasons for the loss of service, and action taken to restore and maintain service;

Type and amount of daily, intermediate and final cover used;

Maintenance and repairs performed on equipment employed at the Site;

Complaints received and actions taken to resolve them;

Emergency situations and actions taken to resolve them; and

Any other information required by the MECP District Manager. The Site will be inspected biannually (twice a year) for the following items:

Confirmed species at risk habitat at buffer demarcations.

Any problems will be addressed immediately. Machinery will be diverted from landfilling operations to assist repairs as required. If additional equipment is required, staff will make the necessary arrangements to rent or purchase the equipment.

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Other inspections related to the operation of the leachate management system and the gas management system are addressed in Sections 7.0 and 8.0, respectively. Reporting procedures and other operational monitoring are discussed in Section 12.1.

14.8.2 Routine Maintenance A routine maintenance program will be employed at the Site to keep the Site clean and in working order. The

following activities will be included in the routine maintenance schedule:

Entrance areas, gates, and signs will be maintained to provide an attractive entrance to the Site;

The paved landfill access road will be wet swept and scraped, if necessary, to prevent accumulation of mud;

The on-Site haul roads will be regraded, with additional granular material being applied as required. This ensures good all-weather access throughout the Site;

All buildings will be kept in a clean tidy appearance, and repaired as required;

All equipment and machinery will be checked and tuned. Repairs will be performed, if necessary;

All ditches and the stormwater ponds will be re-excavated and graded and all culverts cleaned, as necessary, to keep them clear of silt, debris, and weeds;

Areas where landfilling will not be carried out for extended periods and where erosion has resulted will be regraded and, if required, receive additional earth cover;

Finished areas will be routinely checked for erosion and will be regraded and vegetated, as necessary; and

Leachate collection pipes and manholes will be video inspected and cleaned annually for the first five years after placement of waste over the top of each pipe. This frequency may be reduced to once every two (2) years on the basis of inspection results with the approval of the Regional Director.

Detailed maintenance manuals will be prepared for the leachate and gas management systems.

15.0 MONITORING AND REPORTING A comprehensive program of operational, development and environmental monitoring will continue to be implemented. Operation and development monitoring focus on the proper construction, operation, and maintenance of the Site. Environmental monitoring focus on observing and recording change in the environment to forecast and manage impacts off-Site. The following sections describe the inspection, monitoring, and reporting programs.

15.1 Operation and Development Monitoring Landfill operation and development will be monitored and documented regularly. Inspection records will be maintained, detailing the installation of all site facilities and any remedial activities carried out. Site development records will be compiled and submitted with annual reports.

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15.1.1 Development Monitoring Landfill development will be monitored and recorded to assess the progress of Site development and to compare with waste capacity, soil excavation, and leachate and gas generation calculations performed during landfill design. As-built drawings for all major works will be retained on-Site and made available to MECP staff for inspection. Major works include the gas management system, leachate collection system and liner. Each major work will be constructed in accordance with the approved final detailed design and QA/QC procedures will be implemented.

The type of records that will be maintained by the landfill operator include the following:

Volumes of soils excavated on-Site;

Volumes of any clean fill brought to the Site from off-Site sources;

Volumes of topsoil stockpiled;

Volumes of excavated soil stockpiled;

Extent and location of any gravel or sand lenses located during excavation;

Estimates of combined quantities of daily, intermediate, and final cover used;

Leachate volumes pumped for disposal;

Volumes and composition of landfill gas collected and combusted; and

Levels of leachate in the leachate collection systems (when operational).

Cover soil records will be used to assess the current cover needs and forecast future requirements. Leachate and landfill gas records will be used to evaluate the performance of the leachate and landfill gas management systems.

The data obtained through development monitoring is summarized in the Annual Site Development, Operations and Monitoring Report.

15.1.2 Site Inspections As discussed in Section 14.8, the Site will be inspected on a daily, weekly and monthly basis, and use self-evaluation forms to serve as a tool to address and follow-up potential problems.

Any significant operational or maintenance problems, along with the corrective measures taken to mitigate the problems, will be recorded in an Inspection Log. The Inspection Log will be kept on file for at least two (2) years and will be made available to the MECP and the Ridge Landfill Liaison Committee for inspection and photocopying, upon request.

The list of inspection items below summarizes the operation and maintenance inspection required for the Site. They include the items described in Section 14.8.1 and other inspection requirements related to control measures discussed at length in Section 14.0. Inspection duties will be performed by landfill staff at various facilities on-Site (e.g., scale house, leachate and landfill gas management facilities).

The following inspection and operational monitoring is required for operation and maintenance aspects of the Site:

Access and on-Site traffic control: inspection of fencing and lockable gates and monitoring of traffic congestion and queuing;

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Waste control: inspection and recording of incoming waste at the scale house and working face (see Section 15.1.3);

Litter control: inspection of litter fences, on-Site areas (e.g., buffer zones) and off-Site roads and properties;

Odour control: inspection of daily covering, cracks or fissures in the soil cover, and odour at the working face or leachate cleanouts/manholes;

Dust control: inspection of on-Site roads, tracking of soil, vegetation on the final cover, buffer zones, and stockpiles;

Erosion and sediment control: inspection of vegetation, siltation of ditches, conditions of culverts, berms, or ponds;

Leachate management: inspection of leachate seeps or discharges of potentially contaminated runoff to surface water, condition of leachate collection pipes, pumping stations, valve chambers, and the leachate storage tank operation;

Landfill gas control: inspection of combustible-gas alarms, vegetation health, condition of gas wells and collectors, and the gas combustion system operation; and

Noise control: inspection of screening of landfill equipment and operation.

15.1.3 Incoming Waste Records Every waste vehicle entering the Site will be required to stop at the weigh scale, where the driver should check in with the scale operator. With each vehicle passing over the weigh scale, the scale operator notes the following information:

Incoming weight of vehicle;

Origin of waste by municipality (or name of operator and haulage business);

Vehicle identification (truck number or driver name);

Nature of material being disposed (residential, institutional, commercial, solid non-hazardous industrial);

Type of material (waste, clean fill, non-hazardous contaminated soil, leaf and yard waste, recyclables, wood waste, etc.);

Type of vehicle (packer, roll-off, trailer, dump truck, private vehicle, etc.); and

Outgoing weight of vehicle.

Any vehicle entering the Site will be recorded by the scale operator, either against existing business accounts or municipal contracts. If the vehicle is new or belongs to an infrequent user of the Site, then a waybill ticket should be made, with one copy going to the hauler and the remaining part to be used for landfill records.

The Site personnel will collect data in a form suitable for filing and production of the annual report. Summaries of vehicles and waste tonnages arriving at the Site will be generated as required. Besides the summaries produced for the annual report, the year-to-year accumulation of data will enable accurate record-keeping on landfill usage. This will enable landfill staff to plan and budget for future activities.

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15.2 Environmental Monitoring The environmental monitoring program will be established with the following objectives in mind:

To identify potential changes in background chemistry in each of the principal hydrostratigraphic units;

To identify any impact on groundwater that is potentially attributable to the landfill operations. To monitor off-Site surface water quality (upstream and downstream of the Site);

To identify any changes in the pattern of groundwater movement beneath the Site;

To assess water quality of the Stormwater ponds prior to discharge to the municipal drains or flood control facility;

To provide an early indication of any potential impairment or adverse effects on the off-Site environment; and

To trigger and monitor the implementation of contingency measures as required.

15.2.1 Groundwater Monitoring Groundwater monitoring will be carried out as per Appendix D7– Hydrogeological Assessment of the EA Report. Details regarding groundwater sampling frequency, water level monitoring, monitoring station maintenance, and reporting are presented in Appendix D7– Hydrogeological Assessment of the EA Report.

There are 48 monitoring wells included in the groundwater monitoring network for the Ridge Landfill. Six additional well nests will be added to the monitoring program following ECA approval of the proposed expansion. The groundwater monitoring program for the Old Landfill is summarized in Table 15.1. Table 15.2 summarizes the groundwater monitoring program for the West Landfill/Area A and South Landfill/Area B. Table 15.3 summarizes the list of parameters as per Schedule 5 of O.Reg. 232/98 (MOE, 1998). The Landfill Standards (MOE, 2012) recommends that groundwater samples be taken three (3) times per year: once for analysis of the comprehensive list in Table 15.3, and twice for analysis of the indicator parameter list in Table 15.3. Given the extremely slow groundwater velocities through Layer 2 at the Site and the extensive historical water quality data base, retaining the current sampling frequency as listed in Tables 15.1 to 15.2 is appropriate.

Table 15.1: Summary of Groundwater Monitoring Program – Old Landfill

Hydrostratigraphic Layer Sampling Locations Frequency

Layer 1 Shallow Weathered Till

11-I, 16-I, 18-I, 19-I, 20-I, 21-I, 22-I, 25-I, 30-III, 32-III, 44-III 1-II, 3-III, 12-I, 5-II, 13-I, 15-I, 31-I

Twice per year (May and September)

Layer 2 Unweathered Till

3-II, 14-I, 30-II, 32-II, 44-II Twice per year (May and September)

Layer 3 Basal/Bedrock Aquifer

BW-1, BW-4, 32-I, 30-I Twice per year (May and September)

Table 15.2: Summary of Groundwater Monitoring Program – West Landfill/Area A and South Landfill/Area B


Layer 1 Shallow Weathered Till

Existing Wells Twice per year (May and September)

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28-III, 46-III, 47-I, 48-I, 49-A, 50-A, 58-A, 59-A, 60-A, 61-A New Wells (installed in 2012) 62-A, 63-A, 64-A Expansion Wells (installed in 2018) 71-A, 72-A, 73-A, 74-A, 75-A and 76-A

Layer 2 Unweathered Till

Existing Wells 28-II, 46-II, 47-II, 49-B, 50-B Proposed Wells (installed as filling proceeds) 61-B, 64-B Expansion Wells (installed in 2018) 71-B, 72-B, 73-B, 74-B, 75-B and 76-B


Layer 3 Basal/Bedrock Aquifer

Existing Wells 28-I, 46-I, 49-C, 50-C Proposed Wells (installed as filling proceeds) 61-C, 64-C Expansion Wells (installed in 2018) 71-C, 72-C, 73-C, 74-C, 75-C and 76-C


Table 15.3: List of Groundwater Parameters

Comprehensive List (May Samples) Indicator List (September Samples)

Inorganics Inorganics

Alkalinity, Ammonia, Arsenic, Barium, Boron, Cadmium, Calcium, Chloride, Chromium, Conductivity, Copper, Iron, Lead, Magnesium, Manganese, Mercury, Nitrate, Nitrite, Total Kjeldahl Nitrogen, pH, Total Phosphorus, Potassium, Sodium, Total Dissolved Solids, Sulphate, Zinc

Alkalinity, Ammonia, Barium, Boron, Calcium, Chloride, Conductivity, Iron, Magnesium, Nitrate, pH, Sodium, Total Dissolved Solids, Sulphate

Volatile Organics

Benzene, 1,4 Dichlorobenzene, Dichloromethane, Toluene, Vinyl Chloride

Other Organics Other Organics

Chemical Oxygen Demand, Dissolved Organic Carbon, Phenol Chemical Oxygen Demand, Dissolved Organic Carbon

Field Parameters Field Parameters

pH, Conductivity pH, Conductivity

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Monitoring well numbers that are followed by an A, B or C indicate that the well screen is located within hydrostratigraphic Layer 1, Layer 2 or Layer 3 respectively. There is no specific correlation with the roman numerals I, II and III that follow the well numbers and the different hydrostratigraphic layers. These wells were installed in the 1980’s and some were numbered with “I” being the deepest monitoring well and “II” being the next deepest monitoring well at that location.

Water levels will be recorded twice per year, in May and September. Water levels will be used to establish long-term trends in groundwater levels and to provide base data for assessment of fluctuation in water quality data.

Overall, groundwater quality will be evaluated by comparison with the following:

Ontario Drinking Water Standards (ODWS);

Background groundwater quality;

Leachate quality; and

MECP Guideline B-7: The Incorporation of the Reasonable Use Concept into Groundwater Management.

All groundwater monitoring wells will be properly capped, locked and protected from damage. In areas where landfilling is to proceed around monitoring wells, suitable extensions will be added to the wells and they will also be re-secured. All well regardless if they are included in the monitoring program will be regularly assessed and repaired, replaced or decommissioned as required. If a monitoring well is required to be decommissioned, it will be decommissioned in accordance with accepted standard practice that will prevent contamination through the abandoned well and in accordance with Ontario Regulation 903. A report on the decommissioning will be made in the annual monitoring report for the period during which the well was decommissioned.

It is expected that the program of long-term groundwater monitoring in place at the end of the period of landfill operation will be maintained, after landfill closure, for a period of two (2) years, after which time the frequency and location of sampling and the list of analytes will be reviewed in conjunction with the MECP.

In addition, monitoring of off-Site private groundwater wells will be carried out as needed and with the consent of the owners or tenants. Refer to Section 15.2.6 for the private groundwater wells monitoring program details.

15.2.2 Surface Water Monitoring The surface water monitoring locations will be established in the stormwater ponds (locations denoted by SWP) and municipal drains (locations denoted by SW). Each existing and future stormwater pond will be sampled. The surface water monitoring locations in the municipal drains are as follows (refer to Drawing 29):

SW4: Duke Drain at Allison Line and Erieau Road intersection (upstream of the landfill);

SW7: Howard Drain immediately downstream of the Site boundary (downstream of the landfill);

SW11: Howard Drain at Allison Line (upstream of the landfill); and

SW12: Scott Drain at outlet to Howard Drain (upstream of the landfill).

All surface water quality monitoring stations will be sampled throughout the operating life of the Ridge Landfill and thereafter during the leachate contaminating life span.

Table 15.4 summarizes the list of parameters as per Schedule 5 of O.Reg. 232/98 (MOE, 1998). The Landfill Standards (MOE, 2012) recommends that surface water samples be taken four (4) times per year: two (2) for

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analysis of the comprehensive list of Table 15.4, and two (2) other occasions for analysis of the indicator parameter list of Table 15.4. The proposed sampling frequency is March, May, September and December, consistent with the current monitoring program. In addition, the stormwater ponds may be sampled more frequently prior to discharging.

Table 15.4: Surface Water Monitoring Target Parameter List

Comprehensive List (May and September Samples)

Indicator List (March and December Samples)


Alkalinity, Ammonia, Arsenic, Barium, Boron, Cadmium, Chloride, Chromium, Conductivity, Copper, Iron, Lead, Mercury, Nitrate, Nitrite, Total Kjeldahl Nitrogen, pH, Total Phosphorus, Suspended Solids, Total Dissolved Solids, Sulphate, Zinc

Alkalinity, Ammonia, Chloride, Conductivity, Iron, Nitrate, Nitrite, Total Kjeldahl Nitrogen, pH, Total Phosphorus, Suspended Solids, Total Dissolved Solids, Sulphate


Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand, Phenol

Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand, Phenol


Temperature, pH, Conductivity, Dissolved Oxygen, Flow

Temperature, pH, Conductivity, Dissolved Oxygen, Flow

Flow measurements will be undertaken to provide an indication of seasonal quantity variation. If flow is not measurable, surface water level observations will be recorded.

15.2.2.1 Surface Water Assessment Surface water monitoring results will continue to be compared with the Provincial Water Quality Objectives (PWQO).

15.2.2.2 Stormwater Ponds Discharge Objectives The stormwater ponds will be discharged to the municipal drains following confirmation that selected water quality parameters meet the discharge objectives to be established in the ECA approval under the Ontario Water Resources Act.

15.2.3 Leachate Collection System Monitoring The objective of the leachate collection system monitoring is to assess performance of the compliance and determine whether groundwater and surface water are impacted by the landfill. Leachate flow and head measurements will provide data for evaluation of leachate collection system performance.

Leachate levels will be measured in the leachate collection system manholes and compared with ground elevation. Groundwater levels at the weathered clay is close to ground elevation and the manholes are a few metres below ground. Leachate levels measured below ground elevation in the manholes will indicated that the leachate collection system is creating a hydraulic trap and performing as designed.

Leachate chemistry data will be used to interpret whether groundwater and surface water are being impacted by the landfill.

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Samples will be taken at the leachate storage tank or adjacent pump. If sampling shows contaminant levels that correspond to unacceptable predicted impacts in the future, contingency measures for groundwater impacts will be triggered. The contingency measures are presented in Section 17.1.

The leachate collection system monitoring program is summarized in Table 15.5. The proposed list of parameters is consistent with the list of parameters as per Schedule 5 of O.Reg. 232/98 (MOE, 1998). The monitoring frequency is consistent with the Landfill Standards (MOE, 2012) recommended frequency for leachate monitoring.

Table 15.5: Leachate Collection System Monitoring Program

Comprehensive List (Once Per Year) Indicator List (Two Other Occasions Per Year)


Alkalinity, Ammonia, Arsenic, Barium, Boron, Cadmium, Calcium, Chloride, Chromium, Conductivity, Copper, Iron, Lead, Magnesium, Manganese, Mercury, Nitrate, Nitrite, Total Kjeldahl Nitrogen, pH, Total Phosphorus, Potassium, Sodium, Suspended Solids, Total Dissolved Solids, Sulphate, Zinc

Alkalinity, Ammonia, Barium, Boron, Calcium, Chloride, Conductivity, Iron, Magnesium, Nitrate, pH, Sodium, Suspended Solids, Total Dissolved Solids, Sulphate

Volatile Organics

Benzene, 1,4 Dichlorobenzene, Dichloromethane, Toluene, Vinyl Chloride


Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand, Dissolved Organic Carbon, Phenol

Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand, Dissolved Organic Carbon


pH, Conductivity pH, Conductivity

Leachate levels will be measured in the leachate collection manholes and compared with the adjacent ground elevations once a year. This information will be used in the performance assessment of the leachate collection system.

15.2.4 Old Landfill Leachate Level Monitoring The purpose of the leachate level monitoring in the Old Landfill is to allow measurement of leachate levels for comparison against predicted levels and for assessing performance of the final cover. It is proposed to install two leachate monitoring wells within the Old Landfill at the locations shown in Drawing 29 to monitor leachate levels. The proposed leachate monitoring wells will be installed following the completion of the vertical expansion waste filling and intermediate or final cover construction. Leachate levels will be measured twice per year.

15.2.5 Landfill Gas Monitoring The primary purpose of the landfill gas monitoring program is to monitor the performance of the landfill gas collection system to ensure that is operates at optimal efficiency. This will include monitoring of the vacuum, temperature, gas composition, and flow rate within the collection system and at the blower/flare station.

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The sub-surface migration of gas from the landfill is highly unlikely given the installation of the cut-off wall or side slope liner and the physical Site setting. However, as a safety precaution, combustible gas alarms will be installed at all on-Site buildings. On-Site grass cover and planted vegetation will be inspected regularly during operation and post-closure period to detect vegetation distress due to exposure to landfill gas.

15.2.6 Private Groundwater Well Monitoring

There are 15 private groundwater monitoring wells off-Site that will be sampled annually. The number of private monitoring wells will be increased as needed, or as appropriate based on monitoring results, and with the consent of the owners or tenants. Samples will be collected at a point in the plumbing system prior to any in-line treatment systems or water softeners, if practical. Parameters analyzed are the following:

Ammonia as nitrogen

Biochemical Oxygen Demand (BOD)

Calcium

Chloride

Conductivity

Dissolved organic carbon (DOC)

Hardness (as CaCO3)

Iron

Magnesium

Manganese

Nitrate

Nitrite

pH

Phenols

Total Kjeldahl nitrogen (TKN)

Turbidity

Private wells will be sampled in September. A figure showing the location of the private wells and additional details is provided in Appendix D7 – Hydrogeological Impact Assessment of the EA Report.

15.2.7 Air Monitoring An air monitoring program will be completed; following receipt of the amended Waste ECA, a proposed monitoring program will be submitted to the MECP for approval.

It is proposed that the air monitoring program will be consistent with the program completed at the Ridge Landfill in 2014 and will include twenty-four (24) hour samples of total suspended particulate matter (TSP), particulate matter 10 micrometers or less in diameter (PM10), and volatile organic compounds/non-methane organic compounds

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(VOC/NMOC) over a period of six (6) months according to the National Air Pollution Surveillance Program (NAPS) schedule wherever possible.

The sampling will be conducted in general accordance with the MECP Operations Manual for Air Quality Monitoring in Ontario, dated May 2019.

15.3 Complaint Response Procedure A complaint procedure will be maintained on-Site and will include, as a minimum:

Designation of a specific staff to receive any complaints. The designated staff will, within ten (10) working days, respond in writing to the complainant indicating the course of action taken and the outcome;

Posting a telephone number for Site complaints at the Site entrance;

Keeping an accurate record of the following information:

a) the name and address of the complainant;

b) the date and time of the complaint;

c) the nature of the complaint;

d) wind speed and wind direction at the time of the complaint; and

e) details of the response to the complainant, action taken and outcome;

Reporting to each Ridge Landfill Liaison Committee meeting a summary of all public complaints received, courses of action taken and outcomes not reported at previous Ridge Landfill Liaison Committee meetings.

A summary of the complaints will be summarized in the Annual Site Development, Operations and Monitoring Report as described in Section 12.4.

15.4 Annual Reports To assist in the tracking of Site progress and performance, an Annual Site Development, Operations and Monitoring Report for the previous calendar year is prepared. This report will be submitted to the MECP and the Ridge Landfill Liaison Committee.

The report will include the following information:

The results and an interpretive analysis of the results of all groundwater, surface water, landfill gas, leachate collection system monitoring, and leachate monitoring, including the following:

▪ The adequacy of the monitoring programs and recommendations for any modifications to programs as appropriate;

▪ The extent to which the monitoring results indicate compliance with the conditions of the ECA, PWQO, ODWO, the Reasonable Use Guideline and any other relevant statutes and guidelines;

▪ The trend of the monitoring results with respect to future compliance with the conditions of the ECA, PWQO, ODWO, the Reasonable Use Guideline and any other relevant statutes and guidelines; and

▪ The current or expected future need to implement contingency plans and/or additional mitigation measures to ensure compliance with the Conditions of the ECA, PWQO, ODWO, the Reasonable Use Guideline and any other relevant statutes and guidelines;

Summary of Site inspections;

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Site plans showing:

▪ Existing contours of the Site;

▪ Areas of landfilling operation during the reporting period and areas of intended operation during the next reporting period;

▪ Areas of excavation during the reporting period;

▪ The progress of final and interim cover application;

▪ Previously existing Site works, including stockpiling, works installed during the reporting period, and works planned for installation during the next reporting period and the progress of seeding on final and interim cover; and

▪ Areas and quantities where dewatered sewage biosolids were used as daily, intermediate and final cover;

A summary of the quantity of any leachate removed, or treated and discharged, from the Site, during each operating week;

The type and quantity (by weight) of all waste, alternative daily cover, interim cover and final cover disposed or applied during the reporting period;

Calculation of the total volume of the Site capacity used during the reporting period;

A calculation of the remaining capacity of the Site and an estimate of the remaining Site life;

A summary of the weekly, maximum daily and annual tonnage of waste received at the Site;

A summary of the public complaints received and the responses made including the actions taken to resolve these complaints;

Other measures undertaken to reduce or prevent off-Site impacts and to ensure compliance with the MECP’s requirements;

Extent and timing of the contingency measures related to surface water and groundwater that may be needed to be implemented;

Report on the decommissioning of wells that have been decommissioned in the reporting year;

A brief description of the changes to the operational procedures and the resultant changes to the impact management plans; and

A discussion of the operation and performance of the major works at the Site, any operational problems encountered at the Site and the remedial measures taken to alleviate the impacts from those problems, including the control of dust, odour and noise.

15.5 Ridge Landfill Liaison Committee There is a Ridge Landfill Liaison Committee for the Site in which Waste Connections continues to participate. The purpose of the committee is to exchange information with Waste Connections.

The terms of reference, membership, and meeting protocols were established by the committee. The terms of reference for the committee may be altered with the approval of the Regional Director.

All meetings of the Ridge Landfill Liaison Committee will be open to the public and copies of all committee reports and minutes will be made available to the public.

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16.0 SITE CLOSURE As outlined in previous sections, the landfilling areas will be progressively completed and rehabilitated as landfill development reaches final contours. In addition, this D & O Report includes conceptual landfill closure related information, such as:

Description of the end use of the site;

A drawing showing the final contours;

The final waste volume;

The thickness of the final cover;

The material to be used for the final cover;

A plan to control erosion at the final cover; and

A drawing for the ultimate buildout of the landfill gas collection system.

Consideration of the potential effects of climate change have been incorporated into the design of the stormwater management (SWM) ponds, other SWM system components such as ditches, flood control berm and stormwater diversion berms. Climate change effects have also been considered in the slope stability analysis and capacity of the BWTL to treat additional leachate quantities. The potential effects of climate change on the presently designed SWM system and other components of the design that could be affected by climate change will again be considered at the time of preparation of the Closure Plan and submitted as part of the Closure Plan for MECP. If the assessment at that time indicates that modifications to the SWM system are needed as a result of changes to climate change related assumptions or projections for the post-closure period, modifications to the SWM system components will be proposed in the Closure Plan.

A Closure Plan will be submitted to the Regional Director of the MECP for approval when the landfill Site is two years from its projected closure. A Closure Plan appropriate for this Site would include the following:

Plans for long-term fencing and access control;

Details on the final grading, final cover requirements and the source(s) of the cover materials used;

Details of vegetative cover requirements;

SWM system modifications, if any;

Review of slope stability analysis;

Confirmation of capacity of the BWTL for the projected leachate volumes;

End-use plan for the Site;

Plans for continued monitoring of the groundwater, surface water, leachate and landfill gas;

Plans for continued maintenance, operation and monitoring of the engineered facilities at the Site including the leachate collection system, gas management system and the surface water drainage facilities;

Plans and schedules for routine inspection and maintenance of the Site upon closure; and

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Updated contingency plans for groundwater, surface water and gas control problems.

16.1 Site Closure Works Following the application of final cover and topsoil, a vegetative cover will be established to cover 100% of the waste fill areas as soon as weather conditions permit.

An access road will be built to the top of the landfill for maintenance purposes.

The landfill gas collection system will be expanded to cover the balance of the final cover area.

Depending on the end use, Site buildings and facilities will be removed or modified to suit other purposes upon closure.

Any pending surface water diversion berms and downchutes will be constructed to control final cover erosion.

The surface water drainage system will remain in place for long-term management of runoff.

A new sign indicating that the landfill is closed and identifying any alternative for disposal arrangements will replace the existing sign at the Site entrance.

Any pending landscaping will be completed upon closure.

16.2 Post-Closure Care Long-term monitoring and maintenance programs will be maintained for the post-closure care of the Site. These programs will be designed to address:

Groundwater levels and quality;

Surface water quality;

Leachate quantity and quality. The leachate management system will continue to operate until leachate no longer poses a threat to groundwater or surface water quality;

Continuing leachate management;

Continuing landfill gas collection and control;

Landfill settlement;

Integrity of cover;

Erosion control;

Surface water drainage;

Leachate seeps;

Health of vegetation;

Performance of any implemented contingency plans;

Access control and Site security and safety; and

Any other potential impacts on the surrounding environment.

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During the post-closure period, continuous monitoring, maintenance, and repair must be undertaken to provide protection of the environment for the duration of the contaminating life span of the landfill.

The gas collection and control systems will continue to be operated for as long as necessary to prevent unacceptable impacts.

The stormwater ponds will be operated as wet ponds (with outlet valves permanently open).

Erosion, ponding from settlement, and leachate seeps will be corrected, as required.

16.3 End Use An end use will be determined by the owner as part of the Closure Plan. It is likely that public access will be restricted in order to protect the public and to prevent damage to Site infrastructure.

17.0 CONTINGENCY PLANS A contingency plan is required by O.Reg. 232/98 (MOE, 1998) and is defined as “an organized set of procedures for identifying and reacting to an unexpected, but possible occurrence”.

Contingency plans will be "triggered" when observed or predicted impacts are found to be unacceptable. Impacts will be determined through assessment of data collected from the monitoring programs. Contingencies will typically require the installation of additional facilities.

17.1 Groundwater Contingency Plan When considering the contingency plan for groundwater protection, it was recognized that the time for impacts due to the failure of the leachate control system to be detected at monitoring wells in the basal/bedrock aquifer unit (Layer 3) will be very long, given the very slow downward movement through Layer 2. This highlights the importance of monitoring the performance of the leachate control system via regular inspections and water level monitoring in the leachate collection system. If failure of the leachate control system is detected and contingency measures are implemented, there may be no detectable impact resulting from the failure.

Results of the monitoring program can also be used to implement contingency measures. The contingency measures will be triggered by a verified degradation in water quality attributable to the operation of the landfill. Two tiers of the groundwater contingency plan are proposed.

17.1.1 Tier 1 - Investigation In the event of groundwater contamination at compliance wells in excess of a maximum of 85% of the allowable concentration as defined by the Reasonable Use Guideline, Tier 1 of the contingency plan will be implemented. Tier 1 will consist of investigating, in detail, the reason for the exceedance and determining appropriate mitigation measures. In general, the Tier 1 investigation will proceed as follows:

Resample the well(s) that exceeded 85% of the allowable concentration as defined by the Reasonable Use Guideline. The reason for the resampling is to determine if the exceedance was caused by sampling/laboratory error. Three (3) samples will typically be collected for analysis, one month apart. If all three (3) samples are below 85% of the allowable concentration, the exceedance can be attributed to sampling/laboratory error and no further action is necessary;

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Complete an operations review of activities and systems in the vicinity of the well with the exceedance;

Install new monitoring wells in the vicinity of the well with the exceedance, especially between this well and the downgradient property boundary. This is designed to determine the extent of the problem; and

Evaluate whether the identified exceedance will likely cause an exceedance of allowable concentrations at the downgradient property boundary. If an exceedance of allowable concentrations at the downgradient property boundary is determined to be likely, then Tier 2 of the contingency plan will be implemented.

17.1.2 Tier 2 – Design, Approval and Implementation The Tier 2 of the contingency plan will be to design and implement measures that will prevent off-Site migration of groundwater with concentration of parameters greater than allowable concentrations. A detailed design of the proposed measures will be submitted to the MECP for approval prior to implementation. Tier 2 of the contingency plan will consider the two potential pathways for contaminants to migrate from the landfill in groundwater:

Pathway 1 - horizontal movement of contaminated groundwater through the shallow weathered till soils (Layer 1). The preferred contingency plan to mitigate contamination in the weathered till soils (Layer 1) is the installation of a perimeter cut-off wall similar to that used at the Existing Old Landfill waste fill area. If necessary, this contingency can be coupled with a shallow groundwater collection system on the landfill side of the cut-off wall that will collect contaminated groundwater.

Pathway 2 - vertical movement of contaminated groundwater through the dense unweathered, low permeability till soils (Layer 2) to the basal/bedrock aquifer (Layer 3). The mitigation measures to be implemented will likely involve active hydraulic controls (e.g., groundwater purge wells) to prevent contaminated groundwater from moving off-Site in unacceptable concentrations. It should be noted that due to the length of time for contaminants to move through the unweathered till soils, premature failure of the leachate collection system would result in a peak impact on the bedrock aquifer in about 3,000 years and the groundwater would still meet drinking water objectives.

17.2 Surface Water Contingency Plans The water quality in the stormwater ponds is monitored regularly to confirm that it meets surface water quality objectives (refer to Section 15.2.2). Water quality monitoring coupled with routine Site inspections, maintenance and/or changes in operational practices will be applied to minimize surface water impacts.

The stormwater ponds will continue to be operated in batch mode. Before release of water from a stormwater pond, samples will be collected and tested for leachate impact. Test results will be compared against the discharge objectives. Therefore, there will be no discharge to off-Site watercourses until water quality has been confirmed.

If there is evidence of leachate contamination in any of the stormwater ponds, the impacted water will be managed as leachate. In this case, the impacted water may be directed to the leachate collection system. Alternative measures may include recirculation of contaminated surface water back into the landfill. Since the stormwater ponds were sized to include a climate change allowance (i.e., extra capacity), there may be sufficient storage capacity to retain in the impacted stormwater pond by leaving the outlet valve closed for small rainfall events on a temporary basis until the next testing event. This would allow for immediate testing of pond water quality and identification of the source of contamination.

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Uncontrolled leachate breakouts or accidental spills detected by Site inspections may also trigger the contingency plans. In such a case, early detection can minimize or effectively eliminate impacts to surface water, especially if containment of the contamination and repair of the landfill cover is undertaken promptly.

The potential for impacts on surface water as a result of the discharge of contaminated groundwater to the surface is low. The groundwater monitoring program identifies potential groundwater contamination before it can be discharged to surface waters. In the event that groundwater contamination is identified, contingency measures as described in Section 17.1 will be implemented as appropriate, resulting in the protection of both groundwater and surface water resources.

Any changes to the specific trigger levels for the surface water monitoring program will be approved by the MECP prior to the implementation of any changes.

17.3 Old Landfill Leachate Seep Trigger Mechanism and Contingency Plan

As described in Section 7.7, the design of the Old Landfill expansion includes a series of granular finger drains around the perimeter of the Old Landfill footprint connected to the perimeter leachate collector. The purpose of the finger drains is to intercept mounded leachate that migrates towards the perimeter sideslopes of the landfill and to direct this leachate to the perimeter leachate collector, thereby avoiding breakout of seeps at surface and potential impact to surface water. The presence of a seep at surface is an indication that one or more finger drains in the area of the seep may not be effective in intercepting lateral migration of leachate towards the perimeter side slope.

Trigger Mechanism and Corrective Action – Stage 1 Observations for the presence of leachate seeps along the perimeter sideslopes will be carried out over the operational period by site personnel during routine daily and weekly site inspections. A leachate seep that is observed to be flowing (typically associated with an area of reddish orange staining and possibly surficial sloughing of cover soils and vegetation kill) will be considered as having the potential to adversely affect surface water quality and therefore will trigger mitigation. The initial mitigative work for a seep will consist of:

excavating a pit into the waste under the final cover at the seep location and backfilling with coarse granular to promote vertical drainage into the waste. This is a common remedial approach used for a seep that is caused by preferential lateral drainage along a low permeability layer of waste and/or daily cover. To be effective, the pit must fully penetrate through the low permeability layer.

Trigger Mechanism and Corrective Action – Stage 2 The remediated seep area will be monitored daily to determine if the Stage 1 mitigative measure has been successful. If seepage persists, the following mitigative action will be initiated:

install a new finger drain to capture the area of the seep and connect the new finger drain to an adjacent finger drain.

Trigger Mechanism and Corrective Action – Stage 3 If the flowing leachate seep condition persists following the implementation of both the above Stage 1 and 2 mitigative measures, an investigation into potential clogging of the closest existing finger drain(s) will be undertaken. The investigation will involve excavations along the finger drain(s) to examine the condition of the clear stone backfill with respect to bio-chemical clogging. If the clear stone backfill is clogged, the finger drain(s) will be replaced.

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If multiple flowing seeps develop in an area, a continuous granular drainage blanket will be installed beneath the final cover in the area of the seeps, with a separate perforated pipe installed at the toe of the drainage blanket. The perforated pipe would slope towards the perimeter leachate collection system such that the collected seepage is conveyed by gravity directly into a leachate collection system maintenance hole for removal from the site for treatment.

17.3.1 Peer Review The proposed 3-stage trigger and corrective action plan for seep monitoring and remediation was peer reviewed by Dr. Kerry Rowe3. This peer review, documented in Memorandum #2 dated April 5, 2020, states that the above trigger and corrective action plan is appropriate and realistic to address anything from minor local seeps through to more significant and frequent seeps over a larger area. See Sub-Appendix D6-L for peer review Memorandum #2 dated April 5, 2020.

17.4 Old Landfill Leachate Mound Trigger Mechanism and Contingency Plan

The maximum acceptable height of leachate mound in the Old Landfill that would meet compliance with the Reasonable Use Guideline is 28.5 m based on the POLLUTE model analysis completed for the proposed landfill expansion. If the leachate level measured in the leachate monitoring wells of the Old Landfill exceeds 27 m (i.e., elevation 217 masl) above the base elevation of approximately 190 masl, additional leachate monitoring wells will be installed to further assess the leachate mound in the Old Landfill. An assessment will be completed to determine the appropriate location and number of additional monitoring wells. The leachate level monitoring data will be used to prepare a mitigation plan to control the leachate mound height in the unlikely event that the leachate mound exceeds 28.5 m (i.e., elevation 218.5 masl). This mitigation plan will be submitted to MECP for approval. This proposed trigger mechanism and contingency plan is consistent with the recommendation included in the peer review Memorandum # 2 dated April 5, 2020 (Appendix D6-L).

17.5 Other Contingencies Other situations may arise and identified contingency responses are listed below.

Strictly speaking, there are no critical contingency situations for the leachate management system and landfill gas management system. Potential problems will be addressed through adjustments to the construction, retrofitting, expansion or operation of these facilities.

17.5.1 Temporary Leachate Management Various options exist for temporary leachate management in case the Blenheim Wastewater Treatment Lagoons can not temporarily accept leachate for treatment; for example, temporary storage of leachate within the collection system and/or controlled leachate recirculation into the landfill, and/or disposal at the Chatham Wastewater Treatment Plant.

3 Dr. Kerry Rowe is a Professional Engineer, author of over 300 refereed journal papers, 3 books, 14 book chapters, and more than 300 full conference papers; he has extensive research and consulting experience in geosynthetics, waste management and geo-environmental engineering including the design and/or peer review of hydrogeology and/or design for more than 60 landfills in Canada, US and other countries; in 1999, he received the Ontario Ministry of the Environment’s Award of Excellence for Research and Development for his work on the clogging of leachate collection systems; he was the key advisor developing technical aspects of Ontario's current landfill regulation O.Reg. 232/98; he spent 22 years as a professor, including 8 years as Chair of the Department of Civil and Environmental Engineering, at The University of Western Ontario; he is presently a Professor and the Canada Research Chair in Geotechnical and Geo-environmental Engineering in the Department of Civil Engineering at Queen’s University.

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17.5.2 Landfill Gas In case landfill gas odours become a problem for lack of landfill gas collection coverage, the landfill gas collection system can be expanded by installing temporary horizontal collectors or vertical extraction wells. The landfill gas collection system expansion schedule can be revisited and compressed to respond to odours.

17.5.3 Archaeology and Heritage Resources If significant archaeological resources are identified, archaeological testing and possibly excavations will be conducted.

If significant architectural elements are uncovered during unmonitored demolition of heritage features, contact will be made with applicable government agencies.

17.5.4 Transportation If the haul route is closed temporarily due to an emergency, the existing network of county roads is designed to accommodate truck traffic and will be used. Unpaved local roads will only be used as a last resort and only for temporary emergencies.

18.0 DEFINITIONS Approved Waste Fill Area is the approved waste disposal area that encompasses the 131 ha area that is presently approved by the ECA for the disposal of waste and is comprised of the Old Landfill (55.2 ha), West Landfill (55.1 ha) and South Landfill (20.3 ha). The Approved Waste Fill Area is the area within the approved waste fill limits shown on Drawing 3.

Buffer Area, refers to the areas of a landfill site that are not used for landfilling of waste.

Contaminating Life Span according to the Landfill Standards (2012) means,

a) in respect of a landfilling site, the period of time during which the site will produce contaminants at concentrations that could have an unacceptable impact if they were to be discharged from the site; and

b) in respect of a landfilling site and a contaminant or group of contaminants, the period of time during which the site will produce the contaminant or a contaminant in the group at concentrations that could have an unacceptable impact if they were to be discharged from the site.

Cut-off Wall, is a term used in geotechnical engineering, and refers to a vertical clay barrier used to control the spread of contaminants.

East Infill Area, refers to the portion of the Old Landfill within the maximum approved waste fill limit that will be redeveloped to accommodate a minor lateral expansion of the Old Landfill. This area is currently occupied by an inactive stormwater pond labeled as Front Pond in Drawing 2.

Engineered Facility according to the Landfill Standards (2012), means anything affixed to or made part of land that is intended to be a functional element or feature of a landfilling site for more than five (5) years and that is created or put in place by human activity. For the purpose of better understanding the definition of "engineered facility", the following features are examples of common engineered facilities, if they are intended to be functional elements or features of a landfilling site for more than five (5) years:

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1) Berms. 2) Drainage ditches. 3) Liners. 4) Covers. 5) Pumps. 6) Facilities to detect, monitor, control, collect, redirect or treat leachate, surface water or ground water. 7) Facilities to detect, monitor, control, collect, redirect, treat, utilize or vent landfill gas. Flaring, refers to the high temperature destruction (burning) of landfill gas generated by waste in the landfill and collected through a network of wells and pipes.

IC&I, refers to Industrial, Commercial and Institutional waste stream.

Infill Area, refers to the approved waste cell located in the southwest corner of the Old Landfill. The Infill Area will be constructed in 2020.

Landfill Site Area, this term encompasses the 262 ha area identified by the MECP, which includes the fill areas and associated environmental works, and facilities required for the ancillary waste management activities. Note that the limits and area (in hectares) of the Landfill Site Area will be increased to accommodate the proposed landfill expansion.

Leachate Collection System, refers to the on-site system of pipes and drainage aggregate beneath or around a landfill mound that is designed to capture and move leachate to the forcemain and ultimately to the BWTL.

Mitigation, Measures which can lesson potential negative environmental effects.

Old Landfill, this refers to the three waste cells located at the northeast corner of the Landfill Site, adjacent to the entrance driveway. The Old Landfill was closed in 1999.

Proposed Waste Fill Area encompasses the Approved Waste Fill Area and the expansion Waste Fill Area to accommodate the proposed expansion. The Proposed Waste Fill Area is the area within the approved waste fill limit and proposed waste fill limit shown on Drawing 4.

Ridge Landfill Property is the entire land located west of Erieau Road within the property limit shown on Drawing 2. This property is owned by Waste Connections and has an area of approximately 340 hectares (ha). The property is owned by Ridge (Chatham) Holdings L.P., which is a whole subsidiary of Waste Connections.

Service Life according to the Landfill Standards (2012) means the period of time during which a properly maintained engineered facility will function in accordance with the performance specifications for its design.

Site is the area within the Ridge Landfill property that is approved by the ECA, which includes the waste disposal areas, the associated environmental works, and the facilities required for the ancillary waste management activities. The approved Site boundary is shown on Drawings 2 and 3 and has an area of 262 ha.

South Landfill, this refers to the waste cells located south of the Old Landfill. Development of the South Landfill began in August 2016.

Standard Cubic Feet per Minute (scfm), refers to the molar flow rate of a gas corrected to "standardized" conditions of temperature and pressure thus representing a fixed number of moles of gas regardless of composition and actual flow conditions.

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Waste Connections of Canada Inc., or “Waste Connections”, is the proponent for this Undertaking. Waste Connections was formerly Progressive Waste Solutions Canada Inc. Progressive Waste Solutions and Waste Connections merged in an all-stock transaction as of June 1, 2016.

Waste Fill Area is the waste disposal area.

West Landfill refers to the waste cells located west of the Old Landfill.

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Signature Page

Golder Associates Ltd.

Fabiano Gondim, M.Eng., P.Eng. Frank Barone, Ph.D., P.Eng. Senior Waste Engineer/Project Manager Principal

RW/FRG/FSB/PAS/ml

Golder and the G logo are trademarks of Golder Associates Corporation

https://golderassociates.sharepoint.com/sites/34627g/deliverables/d & o report (final eca)/18111331 do report 28apr2020.docx

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REFERENCES Dillon Consulting Limited. 1996. BFI Ridge Landfill Expansion EA. Appendix O – Operation and Development

Report. December 1996.

Dillon Consulting Limited. 2018a. Landfill Mining Assessment Report. Ridge Landfill Expansion EA. June 2018.

Dillon Consulting Limited. 2018b. Interim Alternative Methods Report. December 2018.

Gartner Lee Limited. 1981. Ridge Landfill Site, Hydrogeological Study, August 1981.

Holtz, R.D. and Kovacs, W.D. 1981. An Introduction to Geotechnical Engineering. Prentice-Hall. 1981.

Ministry of the Environment (MOE). (1998). Landfilling Sites: Ontario Regulation (O.Reg.) 232/98. Last Updated: June 2011.

Ministry of the Environment and Climate Change (MOECC). 2017. Considering Climate Change in the Environmental Assessment Process. Available from https://www.ontario.ca/page/considering-climate-change-environmental-assessment-process. Last Update: May 8, 2019. Last accessed in May, 2019.

Ministry of the Environment and Energy (MOEE). (1994a). Guideline B-7: Incorporation of the Reasonable Use Concept into MOEE Groundwater Management Activities. (Formerly Policy 15-08). Available from https://www.ontario.ca/page/guideline-b-7-incorporation-reasonable-use-concept-moee-groundwater-management. Last Update in April, 2019. Last accessed in May, 2019.

Ministry of Environment and Energy (MOEE). (1994b). Water Management Policies, Guidelines, Provincial Water Quality Objectives. PIBS 3303E. Available from: https://www.ontario.ca/page/water-management-policies-guidelines-provincial-water-quality-objectives. Last Update in March, 2019. Last accessed in May, 2019.

Ministry of the Environment (MOE). (1990). General - Waste Management: Ontario Regulation (O.Reg.) 347. Last Updated: December 2013.

Ministry of the Environment (MOE). (2012). Landfill Standards – A Guideline on the Regulatory and Approval Requirements for New or Expanding Landfill Sites. Available from https://www.ontario.ca/page/landfill-standards-guideline-regulatory-and-approval-requirements-newexpanding-land. Last updated on March 22, 2019. Last accessed in May, 2019.

RWDI. (2018). Ontario Regulation 127, NPRI and Greenhouse Gas Emissions - Reporting Year – 2017 - Ridge Landfill, Waste Connections of Canada. RWDI Reference No. 1802511. May 28, 2018.

Risk Sciences International (RSI). 2019. Ridge Landfill Brief Methodology Extreme Rainfall. April 23, 2019. (see Appendix D10-D of the proposed EA document).

Schroeder, P. R., Aziz, N. M., Lloyd, C. M. and Zappi, P. A. (1994). "The Hydrologic Evaluation of Landfill Performance (HELP) Model: User’s Guide for Version 3," EPA/600/R-94/168a, September 1994, U.S. Environmental Protection Agency Office of Research and Development, Washington, DC.

https://www.ontario.ca/page/considering-climate-change-environmental-assessment-process

https://www.ontario.ca/page/considering-climate-change-environmental-assessment-process

https://www.ontario.ca/page/guideline-b-7-incorporation-reasonable-use-concept-moee-groundwater-management

https://www.ontario.ca/page/guideline-b-7-incorporation-reasonable-use-concept-moee-groundwater-management

https://www.ontario.ca/page/water-management-policies-guidelines-provincial-water-quality-objectives

https://www.ontario.ca/page/water-management-policies-guidelines-provincial-water-quality-objectives

https://www.ontario.ca/page/landfill-standards-guideline-regulatory-and-approval-requirements-newexpanding-land

https://www.ontario.ca/page/landfill-standards-guideline-regulatory-and-approval-requirements-newexpanding-land

appendix f design and operations report · 2020. 5. 15. · 3.1 service area ... 15.5 ridge...

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