Strategic Process Engineering
Liquid Treatment Processes at the Blue Plains Advanced Wastewater Treatment Plant
Tier 1 WorkshopBlue Plains Users
October 18, 2004
Tier 1 WorkshopBlue Plains Users
October 18, 2004
2
Today’s AgendaToday’s Agenda
•Scope of Strategic Planning•Blue Plains BNR Performance•Planning Issues and Constraints•Policy Issues•Stakeholder Involvement Plan •Wet Weather Treatment Options•Nitrogen Removal Options
•Scope of Strategic Planning•Blue Plains BNR Performance•Planning Issues and Constraints•Policy Issues•Stakeholder Involvement Plan •Wet Weather Treatment Options•Nitrogen Removal Options
3
Current Regulatory Environment - Uncertainty
Current Regulatory Environment - Uncertainty
• Chesapeake Bay Program goals for 2010?• Tributary Strategies released, not yet final
• Maryland – Nitrogen goal of 3 mg/l?
• DC - Nitrogen goal of 7.5 mg/l?
• Virginia - Nitrogen goal of 4 mg/l?
• Long Term Control Plan?• Treat 193 MG tunnel pump out at Blue Plains over 2 days
• Complete Treatment Required?
• Implementation date? (>2010)
• Draft Blending Policy?• Goal to protect biological processes if water quality is met
• May require more stringent permit limits on 001
• Implementation date? (>2010?)
• Chesapeake Bay Program goals for 2010?• Tributary Strategies released, not yet final
• Maryland – Nitrogen goal of 3 mg/l?
• DC - Nitrogen goal of 7.5 mg/l?
• Virginia - Nitrogen goal of 4 mg/l?
• Long Term Control Plan?• Treat 193 MG tunnel pump out at Blue Plains over 2 days
• Complete Treatment Required?
• Implementation date? (>2010)
• Draft Blending Policy?• Goal to protect biological processes if water quality is met
• May require more stringent permit limits on 001
• Implementation date? (>2010?)
4
Need for PlanningNeed for Planning
• Blue Plains now at 90% of capacity• BNR process now degrades during storm flows• Chesapeake Bay Program calls for higher N removal
• Cost effective approach - limit peak flows to BNR
• LTCP Tunnel Pump out increases peak flow duration• Sustained flows at 450 MGD for 2 days after storm• Back to back storms could extend high flows one week• BNR performance will degrade further
• Goals introduce conflicting treatment requirements• BP Users flow management - Ave/Peak Capacity
• Holistic approach to planning is needed
• Blue Plains now at 90% of capacity• BNR process now degrades during storm flows• Chesapeake Bay Program calls for higher N removal
• Cost effective approach - limit peak flows to BNR
• LTCP Tunnel Pump out increases peak flow duration• Sustained flows at 450 MGD for 2 days after storm• Back to back storms could extend high flows one week• BNR performance will degrade further
• Goals introduce conflicting treatment requirements• BP Users flow management - Ave/Peak Capacity
• Holistic approach to planning is needed
5
WASA’s Implementation of Low Cost BNR
WASA’s Implementation of Low Cost BNR
• Use existing tankage
• Operational changes
• Use existing tankage
• Operational changes
• Denit Demonstration
• Full scale BNR @ 7.5
• DC 1st to achieve goal
• Waste Nitrification WAS to Secondary
• Improve process control – Nit/Denit Upgrade contract
• Ongoing DWT Research
• Denit Demonstration
• Full scale BNR @ 7.5
• DC 1st to achieve goal
• Waste Nitrification WAS to Secondary
• Improve process control – Nit/Denit Upgrade contract
• Ongoing DWT Research
6
Monthly Flow into Blue Plains 2001-2004
Monthly Flow into Blue Plains 2001-2004
0
50
100
150
200
250
300
350
400
450
500
Month
0
5
10
15
20
25
Rainfall (inches) TOTAL GW Fairland (relative elevation in feet)
Rainfall (inches)
Total Blue Plains Influent
Groundwater level (feet)
20032002
7
Nitrogen Removal Performance
Nitrogen Removal Performance
Twelve Month Rolling Average Since Full-Scale Denitrification
200
220
240
260
280
300
320
340
360
380
400
J-00M
-00M
-00J-00
S-00N-00
J-01M
-01M
-01J-01
S-01N-01
J-02M
-02M
-02J-02
S-02N-02
J-03M
-03M
-03J-03
S-03N-03
J-04M
-04M
-04J-04
12 Month Period Ending
Pla
nt
Infl
uen
t F
low
(m
gd
)
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
TN
Dis
char
ge,
Mlb
/Yr
Chesapeake Bay Agreement 1985 Total Nitrogen Discharged
Blue Plains Total Nitrogen Discharged 12 Month Plant Influent Average Flow
1985 Total Nitrogen Discharged
Chesapeake Bay Goal8,467,200 lb/Yr
2001 2002 2003 20042000
8
Nitrogen RemovalPerformance
Nitrogen RemovalPerformance
Total Nitrogen DischargeMonthly Average since Full-Scale Denitrification
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
Sep-01 Jan-02 May-02 Sep-02 Jan-03 May-03 Sep-03 Jan-04 May-04
Mo
nth
ly A
vera
ge
TN
Dis
char
ge,
m
g/l
0
50
100
150
200
250
300
350
400
450
Mo
nth
ly A
vera
ge
Pla
nt
Infl
uen
t F
low
(m
gd
)
TN Discharge Monthly Average Plant Influent Flow Monthly Average
2001 2002 2003 2004
9
Performance SummaryPerformance Summary
• Blue Plains has met CBP goals• BNR performance is most influenced by:
• Temperatures
• Groundwater infiltration
• Storm flows
• BUT, peak flows have been limited by:• Construction – lower peak wet weather flows
• Upstream pump station capacity
• ENR Design Challenge:Blue Plains has to handle years with above average rainfall and expected temperature range
• Blue Plains has met CBP goals• BNR performance is most influenced by:
• Temperatures
• Groundwater infiltration
• Storm flows
• BUT, peak flows have been limited by:• Construction – lower peak wet weather flows
• Upstream pump station capacity
• ENR Design Challenge:Blue Plains has to handle years with above average rainfall and expected temperature range
10
Advanced Wastewater Treatment Plant at Blue PlainsRated Capacity 309 MGDRated Capacity 370 MGDRated Capacity 370 MGD with half-plant denitrificationRated Capacity 370 MGD with full plant
denitrification
11
CHALLENGES FOR ENRCHALLENGES FOR ENR
• Blue Plains is at 90% capacity
• Primary clarifier capacity limits performance
• Biological Clarifier capacity also limited
• Full scale BNR has reduced plant safety factor
• New digesters will increase N load to BNR process by 30%
• Pump station rehabilitation will result in higher peak storm flows to Blue Plains
• LTCP tunnel pump out brings higher sustained flows to Blue Plains after the storm event
• Blue Plains is at 90% capacity
• Primary clarifier capacity limits performance
• Biological Clarifier capacity also limited
• Full scale BNR has reduced plant safety factor
• New digesters will increase N load to BNR process by 30%
• Pump station rehabilitation will result in higher peak storm flows to Blue Plains
• LTCP tunnel pump out brings higher sustained flows to Blue Plains after the storm event
12
Blue Plains New Digestion FacilityBlue Plains New Digestion Facility
Existing SolidsExisting SolidsProcessing BuildingProcessing Building
Proposed DigestionProposed DigestionFacilityFacility
13
WASA Needs AnswersWASA Needs Answers
• How does WASA respond to CBP initiatives for higher nitrogen removal? (2010)
• How does WASA achieve LOT for N removal, if a goal and if a permit requirement?
• What facilities are needed to treat combined sewer tunnel pump-out flow? (>2010)
• How does WASA achieve higher levels of treatment for excess flow?
• What are roles of nutrient trading and creative permitting?
• What is the impact of BP User wet weather flow reduction strategies?
• How does WASA respond to CBP initiatives for higher nitrogen removal? (2010)
• How does WASA achieve LOT for N removal, if a goal and if a permit requirement?
• What facilities are needed to treat combined sewer tunnel pump-out flow? (>2010)
• How does WASA achieve higher levels of treatment for excess flow?
• What are roles of nutrient trading and creative permitting?
• What is the impact of BP User wet weather flow reduction strategies?
14
Policy IssuesPolicy Issues
• Treatment level for wet weather flows• Excess flow
• CSS Tunnel pump out
• Peak flow ratio to complete treatment
• Bubble permit for Outfalls 001 and 002
• Blue Plains NPDES Permit• Relative to varying state Tributary Strategies
• TN removal – goal versus permit requirement
• Permit limits – daily, weekly, monthly requirements
• Nitrogen equivalency – still on the table?
• Treatment level for wet weather flows• Excess flow
• CSS Tunnel pump out
• Peak flow ratio to complete treatment
• Bubble permit for Outfalls 001 and 002
• Blue Plains NPDES Permit• Relative to varying state Tributary Strategies
• TN removal – goal versus permit requirement
• Permit limits – daily, weekly, monthly requirements
• Nitrogen equivalency – still on the table?
15
Planning ApproachPlanning Approach
• Define Performance-based alternatives for nutrient levels and wet weather flows
• Define new facilities/costs for alternatives• Define Worst-Case Scenario
• CS tunnel pump out requires complete treatment
• Excess flow requires complete treatment
• Limit of technology for nitrogen removal
• Define cost-effective approaches• Expert Technical Advisory Group• Stakeholder input to focus alternatives
• Define Performance-based alternatives for nutrient levels and wet weather flows
• Define new facilities/costs for alternatives• Define Worst-Case Scenario
• CS tunnel pump out requires complete treatment
• Excess flow requires complete treatment
• Limit of technology for nitrogen removal
• Define cost-effective approaches• Expert Technical Advisory Group• Stakeholder input to focus alternatives
Goal of the Facilities Plan: Identify & define projects for inclusion in the CIP
Goal of the Strategic Plan:Provide WASA with a blueprint to cost-effectively meet regulatory requirements
18
Two-tier Stakeholder Involvement Plan
Two-tier Stakeholder Involvement Plan
• Tier I – Blue Plains Users• BP Technical Committee and Regional Committee
• Loudoun County, invited to BPTC/RC for strategic planning topics
• Tier II – Blue Plains Users and Regulators• DCDOH (nutrient, CSO)
• EPA Region III (nutrient, CSO, capacity)
• EPA CBP (nutrient, CSO, capacity)
• EPA Headquarters (nutrient, CSO, capacity)
• MDE/ MD DNR (nutrient)
• VA DEQ (nutrient)
• Tier I – Blue Plains Users• BP Technical Committee and Regional Committee
• Loudoun County, invited to BPTC/RC for strategic planning topics
• Tier II – Blue Plains Users and Regulators• DCDOH (nutrient, CSO)
• EPA Region III (nutrient, CSO, capacity)
• EPA CBP (nutrient, CSO, capacity)
• EPA Headquarters (nutrient, CSO, capacity)
• MDE/ MD DNR (nutrient)
• VA DEQ (nutrient)
19
Tier 1-Blue Plains User Involvement Provides: Tier 1-Blue Plains User Involvement Provides:
• WASA an opportunity to provide information on technologies, benefits, and costs to the users.
• A forum for BP User input on the process and technical issues and relative merits of the alternatives.
• A forum to discuss the cost and benefits of alternatives and set priorities
• WASA an opportunity to provide information on technologies, benefits, and costs to the users.
• A forum for BP User input on the process and technical issues and relative merits of the alternatives.
• A forum to discuss the cost and benefits of alternatives and set priorities
20
Tier 2 Stakeholder Involvement Provides:
Tier 2 Stakeholder Involvement Provides:
• WASA an opportunity to provide information on technologies, costs and tradeoffs to the regulators.
• WASA with information from the regulatory agencies on acceptability of options.
• A forum to discuss the cost and benefits of alternatives and set priorities.
WASA wants to be proactive in the “creative regulatory” process
• WASA an opportunity to provide information on technologies, costs and tradeoffs to the regulators.
• WASA with information from the regulatory agencies on acceptability of options.
• A forum to discuss the cost and benefits of alternatives and set priorities.
WASA wants to be proactive in the “creative regulatory” process
21
Outreach ActivitiesOutreach Activities
Purpose:
• To inform the public and interested groups.
Target Audience:
• ANCs and environmental groups.Information Available:
• On WASA’s Website
• At public meetings
• Draft Facilities Plan for public review.
Purpose:
• To inform the public and interested groups.
Target Audience:
• ANCs and environmental groups.Information Available:
• On WASA’s Website
• At public meetings
• Draft Facilities Plan for public review.
22
Stakeholder Activities Plan Stakeholder Activities Plan
OctJul Aug Sep Dec Jan Feb Mar Apr May JunNov
2004 20052004 2005
Technical StakeholderWorkshops
Technical StakeholderWorkshops
Technical and Policy StakeholderWorkshops
Technical and Policy StakeholderWorkshops
Public MeetingsPublic Meetings
IntroductoryIntroductory
Draft PlanDraft Plan
Alternatives/costs Draft PlanAlternatives/costs Draft Plan
23
Inputs to WASA’s Decision Making Process
Inputs to WASA’s Decision Making Process
REGULATORS Chesapeake Bay Program
Tributary Strategies
Bay Water Quality Model
NPDES Permitting
REGULATORS Chesapeake Bay Program
Tributary Strategies
Bay Water Quality Model
NPDES Permitting
DC WASADC WASA
Strategic Planning
Facilities
Costs
Pollutant/Nutrient Loads
Strategic Planning
Facilities
Costs
Pollutant/Nutrient Loads
COGNutrient Analysis studies
Nutrient Trading Opportunities
Non-Point Sources of Nutrient
COGNutrient Analysis studies
Nutrient Trading Opportunities
Non-Point Sources of Nutrient
DC WASA BOARD
DC WASA BOARDPUBLICPUBLIC
DiscussionWet Weather Treatment Options
25
POSSIBLE OPPORTUNITIES
POSSIBLE OPPORTUNITIES
Blue Plains has “Overhead”• Wet Weather Flows
• Sludge Digestion Recycles
• Gravity Thickener Overflow
• Filter Backwash
Reducing the “Overhead”Could:• Improve BNR performance
• Reduce future BNR capital cost
• Reduce O&M cost
• Better manage wet weather flows
Blue Plains has “Overhead”• Wet Weather Flows
• Sludge Digestion Recycles
• Gravity Thickener Overflow
• Filter Backwash
Reducing the “Overhead”Could:• Improve BNR performance
• Reduce future BNR capital cost
• Reduce O&M cost
• Better manage wet weather flows
26
Policy IssuesPolicy Issues
• Treatment level for wet weather flows• Excess flow
• CSS Tunnel pump out
• Peak flow ratio to complete treatment
• Bubble permit for Outfalls 001 and 002
• Blue Plains NPDES Permit• Relative to varying state Tributary Strategies
• TN removal – goal versus permit requirement
• Permit limits – daily, weekly, monthly requirements
• Nitrogen equivalency – still on the table?
• Treatment level for wet weather flows• Excess flow
• CSS Tunnel pump out
• Peak flow ratio to complete treatment
• Bubble permit for Outfalls 001 and 002
• Blue Plains NPDES Permit• Relative to varying state Tributary Strategies
• TN removal – goal versus permit requirement
• Permit limits – daily, weekly, monthly requirements
• Nitrogen equivalency – still on the table?
27
Wet Weather FlowsWet Weather Flows
Excess flow & combinedtunnel sewer pump outflow scenarios:• Complete treatment• Equivalent to secondary• Primary
Policy Issues:• What level of treatment
is required?• Can storm peaks to
complete treatment be reduced?
Excess flow & combinedtunnel sewer pump outflow scenarios:• Complete treatment• Equivalent to secondary• Primary
Policy Issues:• What level of treatment
is required?• Can storm peaks to
complete treatment be reduced?
28
Wet Weather FlowsTreatment options
Wet Weather FlowsTreatment options
Compressible Filters
SLUD GE
HYDRO CYC LO NE
POLYMER
INJECTION M ATURATION
PLATE SETTLERW ITH SCRAPER
CLARIFIEDWATER
M ICR OSAND AND SLUDG ETO HYDROCYCLONE
M ICR O-SAND
RAW WATER
COAGULANT
Ballasted Settling
29
CSO Characterization for Tunnel Pump Out
CSO Characterization for Tunnel Pump Out
• Event Mean Concentrations*, mg/l• Total Suspended Solids – 156
• Total Nitrogen – 4.8
• Total Phosphorus – 1.0*Flow weighted, Source: CSS LTCP
Relative TN Loads, Lb/YearCSO Tunnel BP Outfall 00273,500 8,447,000 - 370 mgd @ 7.5 mg/l(untreated) 5,632,000 - 370 mgd @ 5 mg/l
3,379,000 - 370 mgd @ 3 mg/l
• Event Mean Concentrations*, mg/l• Total Suspended Solids – 156
• Total Nitrogen – 4.8
• Total Phosphorus – 1.0*Flow weighted, Source: CSS LTCP
Relative TN Loads, Lb/YearCSO Tunnel BP Outfall 00273,500 8,447,000 - 370 mgd @ 7.5 mg/l(untreated) 5,632,000 - 370 mgd @ 5 mg/l
3,379,000 - 370 mgd @ 3 mg/l
30
Effective Blue Plains2010 Annual TN GoalEffective Blue Plains2010 Annual TN Goal
JurisdictionAllocated IMA
Flows (MGD)
Various State TN Goals (mg/L)
DC 152.5 7.5
WSSC 169.6 3.0
Fairfax 31.0 4.0
Loudoun 13.8 4.0
Other VA 3.1 4.0
Blue Plains 370.0 4.98
31
Alternative Strategies for Additional Nitrogen Removal
Alternative Strategies for Additional Nitrogen Removal
• Alternative Total Nitrogen Discharge from Blue Plains• Current NPDES Permit – 7.5
• Current 2004 Tributary Strategies – 5.0
• Limit of Technology – 3.0
• TN Load to Potomac at 370 mgd
• Alternative Total Nitrogen Discharge from Blue Plains• Current NPDES Permit – 7.5
• Current 2004 Tributary Strategies – 5.0
• Limit of Technology – 3.0
• TN Load to Potomac at 370 mgd
• 23,140 lbs/d 8,447,200 lbs/yr 7.5 mg/l
• 15,430 lbs/d 5,631,600 lbs/yr 5.0 mg/l
• 9,260 lbs/d 3,378,900 lbs/yr 3.0 mg/l
• 23,140 lbs/d 8,447,200 lbs/yr 7.5 mg/l
• 15,430 lbs/d 5,631,600 lbs/yr 5.0 mg/l
• 9,260 lbs/d 3,378,900 lbs/yr 3.0 mg/l
32
Planning for Effluent NitrogenPlanning for Effluent Nitrogen
Alternatives for:• 5 mg/l and 3 mgN/L
Regulatory Issues• Does CSS Tunnel pump out
require complete treatment?• Possible to limit wet
weather peaks <740 mgd?• Impact of bubbles and
nutrient trading• Goal or permit requirement?• Daily, weekly, monthly
permit levels?
Alternatives for:• 5 mg/l and 3 mgN/L
Regulatory Issues• Does CSS Tunnel pump out
require complete treatment?• Possible to limit wet
weather peaks <740 mgd?• Impact of bubbles and
nutrient trading• Goal or permit requirement?• Daily, weekly, monthly
permit levels?
33
Nitrogen Removal OptionsNitrogen Removal Options
• Stay with two sludge system• Optimize primary treatment
• Optimize secondary process to remove TN
• Optimize centrate treatment
• Add nitrification reactor volume
• Convert to a single sludge system• Lowers clarifier overflow rates
• Reliability concerns?
• Add denitrification filters• Reliability – at significant capital cost
• New technologies available to reduce cost
• Stay with two sludge system• Optimize primary treatment
• Optimize secondary process to remove TN
• Optimize centrate treatment
• Add nitrification reactor volume
• Convert to a single sludge system• Lowers clarifier overflow rates
• Reliability concerns?
• Add denitrification filters• Reliability – at significant capital cost
• New technologies available to reduce cost
34
Sludge Digestion Centrate Treatment
Sludge Digestion Centrate Treatment
• Low flow; high ammonia load – increases load to BNR by 30%
• Side stream or main flow treatment options?
• Side stream treatment may:• Save operating cost
• Increase reliability
• Optimize TN removal
• Low flow; high ammonia load – increases load to BNR by 30%
• Side stream or main flow treatment options?
• Side stream treatment may:• Save operating cost
• Increase reliability
• Optimize TN removal
35
Other SidestreamsOther Sidestreams
• Filter Backwash• High “Instantaneous”
Hydraulic Peaks
• Removal of recycle will lower loading to clarifiers
• Gravity Thickener Overflow
• Filter Backwash• High “Instantaneous”
Hydraulic Peaks
• Removal of recycle will lower loading to clarifiers
• Gravity Thickener Overflow
36
Cost Assumptions for Improved Nitrogen Removal
Cost Assumptions for Improved Nitrogen Removal
• Increased wet weather peaks from pump station upgrades
• Digester recycle load adds 30% load to BNR
• LTCP Pump out to complete treatment
• Flows up to 740 mgd for a maximum of 4 hours and up to 511 mgd indefinitely
• Cost estimates are planning level (+50%/-30%)
• Increased wet weather peaks from pump station upgrades
• Digester recycle load adds 30% load to BNR
• LTCP Pump out to complete treatment
• Flows up to 740 mgd for a maximum of 4 hours and up to 511 mgd indefinitely
• Cost estimates are planning level (+50%/-30%)
37
Blue Plains UsersFlow Reduction Strategies
Blue Plains UsersFlow Reduction Strategies
• BP User peak flows above IMA targets
• DC WASA flow reduction plan in place
• BP Users have sewer inspection and correction programs
• Strategic planning will assume that flow reduction programs will bring each user within IMA allocations
• BP User peak flows above IMA targets
• DC WASA flow reduction plan in place
• BP Users have sewer inspection and correction programs
• Strategic planning will assume that flow reduction programs will bring each user within IMA allocations
38
Policy IssuesPolicy Issues
• Treatment level for wet weather flows• Excess flow
• CSS Tunnel pump out
• Peak flow ratio to complete treatment
• Bubble permit for Outfalls 001 and 002
• Blue Plains NPDES Permit• Relative to varying state Tributary Strategies
• TN removal – goal versus permit requirement
• Permit limits – daily, weekly, monthly requirements
• Nitrogen equivalency – still on the table?
• Treatment level for wet weather flows• Excess flow
• CSS Tunnel pump out
• Peak flow ratio to complete treatment
• Bubble permit for Outfalls 001 and 002
• Blue Plains NPDES Permit• Relative to varying state Tributary Strategies
• TN removal – goal versus permit requirement
• Permit limits – daily, weekly, monthly requirements
• Nitrogen equivalency – still on the table?
End of presentationFurther Discussion
40
Overview of Plan Development Process
Overview of Plan Development Process
Ballasted Settling
2 or 1 Sludge System
Centrate Treatment
Denit Filters
Sidestream treatment SWW
Ballasted Settling
2 or 1 Sludge System
Centrate Treatment
Denit Filters
Sidestream treatment SWW
User Capacity Issues
User Capacity Issues
EPA Proposed Rule for Wet
Weather Flows
EPA Proposed Rule for Wet
Weather Flows
Long Term Control PlanLong Term
Control Plan
Chesapeake Bay Program
Chesapeake Bay Program
Real Estate Issues
Real Estate Issues
Wet Weather Treatment
Alternatives
Wet Weather Treatment
Alternatives
Nitrogen Removal
Alternatives
Nitrogen Removal
Alternatives
Increased Capacity
Alternatives
Increased Capacity
Alternatives
Feasibility Review
Feasibility Review
Recommended Facilities and
Costs
Recommended Facilities and
Costs
Processmodel
Processmodel
Capital costsCapital costs
O&M CostsO&M Costs
Ease of Operations
Ease of Operations
41
Average Annual Influent Flows to Blue Plains
Average Annual Influent Flows to Blue Plains
JURISDICTIONS - 12 MONTH ROLLING AVERAGE FLOWS VS
IMA ALLOCATIONS (SHOWN SOLID)
179.424
1.96011.26229.700
152.023
374.369
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
450.0
APRIL 2003 - MARCH 2004
FL
OW
(M
GD
)
BLUE PLAINS WSSC FAIRFAX LCSA OTHER P.I.** USERS
D.C.
31.0
169.6
13.83.1
* 152.5
* - INCLUDES 4.5 MGD
P.I.** RESERVED
370.0
** POTOMAC INTERCEPTOR
42
IMA Allocated Peak FlowIMA Allocated Peak FlowTotal Peak Flow = 1,076 MGDTotal Peak Flow = 1,076 MGD
JURISDICTIONS - HISTORICAL PEAK FLOWS VS
IMA ALLOCATIONS (SHOWN SOLID)
308
33108
521
970
0.0
200.0
400.0
600.0
800.0
1000.0
FL
OW
(M
GD
)
BLUE PLAINS WSSC FAIRFAX LCSA D.C.
71.0
425
32
* - INCLUDES 4.5 MGD
P.I.** RESERVED
1076
** POTOMAC INTERCEPTOR
541
43
Estimated Infiltration and Inflow into Blue Plains
Estimated Infiltration and Inflow into Blue Plains
Based on assumptions for I/I used in the Regional Wastewater Flow Forecast ModelBased on assumptions for I/I used in the Regional Wastewater Flow Forecast Model
0
50
100
150
200
Jun-01 Aug-01 Oct-01 Dec-01 Feb-02 Apr-02 Jun-02 Aug-02 Oct-02 Dec-02 Feb-03 Apr-03
MG
D
D.C. WSSC FAIRFAX LCSA
44
Peak Influent Flow to Blue Plains during Storms
= 1076 MGD
Peak Influent Flow to Blue Plains during Storms
= 1076 MGD
Average Annual Flow = 370 MGD
Average Annual Flow = 370 MGD
Dry Weather Diurnal Peak Flow = 416
MGD
Dry Weather Diurnal Peak Flow = 416
MGD
Infiltration Flow
= 100 MGD
Infiltration Flow
= 100 MGD
Storm Inflow = 560 MGD
Storm Inflow = 560 MGD
45
Daily Average Influent Flow to Blue Plains 2002-2003
Daily Average Influent Flow to Blue Plains 2002-2003
Daily Average Influent Flow - 2002/3
0
100
200
300
400
500
600
700
01/02 05/02 08/02 12/02 04/03 08/03 12/03Date (mm/yy)
Flow
(mgd
)
Average Dry Weather Flow 297 mgdAverage Dry Weather Flow 297 mgd