works approval application supporting information pinjarra

Works Approval Application

Supporting information

Pinjarra Alumina Refinery

Pinjarra Oxalate Bioreactor Facility Upgrade

March 2020

Version Date Description Prepared Reviewed Date Submitted to DWER

Draft 29/01/2020 Draft for internal review L Vergone A Price - Final 20/03/2020 Final review L Vergone A Price

Alcoa of Australia Limited 2

Table of Contents 1. Purpose and Scope of Assessment .......................................................................................... 3

2. Background ................................................................................................................................... 3

2.1. Oxalate Bioremoval process description .................................................................................. 4

2.2. Current oxalate destruction capacity ......................................................................................... 5

3. Overview of Oxalate Bioremoval Facility Upgrade Project .................................................... 5

3.1. Project schedule ........................................................................................................................... 5

3.2. Infrastructure and equipment...................................................................................................... 5

4. Legislative Context ....................................................................................................................... 7

4.1. Part IV of EP Act ........................................................................................................................... 7

4.2. Contaminated sites ...................................................................................................................... 7

4.3. Other relevant approvals ............................................................................................................. 7

4.3.1. Planning approvals ............................................................................................................... 7

4.3.2. Department of Water and Environmental Regulation (Water) ....................................... 7

4.3.3. Department of Jobs, Tourism, Science and Innovation ................................................. 7

4.3.4. Department of Mines, Industry Regulation and Safety ................................................... 8

4.4. Part V of the EP Act ..................................................................................................................... 8

4.4.1. Amendment notices ............................................................................................................. 8

4.4.2. Compliance history ............................................................................................................... 8

4.4.3. Noise impact assessment ................................................................................................... 8

4.4.4. Clearing of native vegetation .............................................................................................. 8

5. Consultation .................................................................................................................................. 8

6. Location and Siting ....................................................................................................................... 9

6.1. Siting context ................................................................................................................................. 9

6.2. Residential and sensitive premises ......................................................................................... 11

6.3. Specified ecosystems ................................................................................................................ 11

6.4. Groundwater and surface water sources ................................................................................ 12

7. Risk Assessment and Controls ................................................................................................ 15

7.1. Identification of potential impacts ............................................................................................. 15

7.2. Noise emissions ......................................................................................................................... 19

7.3. Odour and gaseous emissions ................................................................................................. 21

7.4. Discharges to land ..................................................................................................................... 22

8. Reference List ............................................................................................................................. 23

9. Appendix ...................................................................................................................................... 24


1. Purpose and Scope of Assessment Alcoa of Australia Limited (Alcoa) proposes to upgrade its Oxalate Bioremoval Facility at the Pinjarra Alumina Refinery by installing a third Bioreactor unit with an additional design capacity of approximately 22 tonnes of sodium oxalate destruction per day. The body of this report provides contextual information about the proposed works to the Department of Water and Environment Regulation (DWER) to support Alcoa’s application for a Works Approval under Part V of the Environmental Protection Act 1986 (EP Act). The scope of this assessment is specific to the predicted emissions and discharges from the construction, commissioning and operation of the Oxalate Bioremoval Facility upgrade. Estimates for predicted emissions and discharges have been determined using available emissions monitoring data for the existing Oxalate Bioremoval Facility and other sources at Pinjarra Refinery. The environmental risk of emissions and discharges from the existing Pinjarra Refinery are not included in this assessment, however they are used to compare the predicted environmental impacts of the Oxalate Bioremoval Facility upgrade to the total emissions and discharges from the Pinjarra Refinery. 2. Background The Pinjarra Refinery is situated in the Shire of Murray in the Peel region, approximately 90km south of Perth and 5km east of the town of Pinjarra, on Alcoa owned land. Pinjarra Refinery commenced operations in 1972 and is subjected to the conditions of the environmental Licence L5271/1983/14, and other relevant approvals including Ministerial Statement 646 granted under Part IV of the EP Act, the Alumina Refinery (Pinjarra) Agreement Act 1969, and the Alumina Refinery Agreements (Alcoa) Amendment Act 1987. The Pinjarra Refinery operates continuously 24 hours a day, 7 days per week. Bauxite feed material used at the Pinjarra Refinery is mined and transported on an overland conveyor from the Huntly Mine Site. The bauxite is processed by the Pinjarra Refinery using the Bayer Process and refined into alumina. The four main steps in the Bayer Process are digestion, clarification, precipitation and calcination. The Pinjarra Refinery utilises a third-party railway network connecting the Wagerup Refinery, Kwinana Refinery, Kwinana Port and Bunbury Port for the purpose of blending alumina, exporting alumina and bauxite, and for importing bulk caustic for use in the Bayer Process. Organic matter within the bauxite breaks down in caustic liquor forming various carbon compounds, primarily sodium oxalate, which are impurities in the Bayer Process. Sodium Oxalate (Oxalate) accumulates in the recycled caustic liquor circuit and impacts alumina product quality and yield, and therefore is extracted from the process for destruction or storage. Pinjarra Refinery uses two destruction methods, thermal destruction through an oxalate kiln and biological destruction through two continuous bioreactor units. The existing Oxalate Bioremoval Facility was assessed and approved for construction and operation by the DWER in 2011 (Works Approval W4915/2011/1). Further details can be found in Works Approval Application Supporting information, Pinjarra Alumina Refinery Oxalate Bioremoval Facility, 25 March 2011.


2.1. Oxalate Bioremoval process description The process flow diagram for the Oxalate Bioremoval Facility is shown in Figure 1, excluding the proposed third bioreactor unit. There are two ways oxalate is transferred to the Plant Oxalate Storage Tank; oxalate is either removed from the Bayer process through existing infrastructure or is transported from oxalate storage facilities and pumped into the Plant Oxalate Storage Tank. The treatment of oxalate involves pumping oxalate from the Plant Oxalate Storage Tank into the Feed Preparation Tank where it is mixed with water to achieve the required Total Alkalinity (TA). The Feed Preparation Tank supplies the two Bioreactor Units with a constant feed of oxalate. The two Bioreactor units comprise of individual Bioreactor tanks, which contain naturally occurring alkaliphilic bacteria that convert oxalate to sodium bicarbonate under aerobic conditions. Air is supplied to the Bioreactor Tanks as the biological process is aerobic and a loss of air supply will result in the gradual death of the aerobic mass and will allow the anaerobic degradation of oxalate using sulphate as an electron acceptor, producing hydrogen sulphide. The dissolved oxygen in the Bioreactor Tanks is controlled by the addition of ambient air as the source of oxygen via a blower system. The blower system is comprised of a blower for each Bioreactor Tank and one spare blower.

Figure 1: Pinjarra Oxalate Bioremoval Facility process flow diagram excluding proposed third unit


2.2. Current oxalate destruction capacity Currently the Pinjarra Refinery generates approximately 82 tonnes per day (tpd) of oxalate. Oxalate is destroyed via either the Oxalate Kiln or the Oxalate Bioremoval Facility. Currently Alcoa is unable to consistently destroy all of the oxalate generated. During periods of planned maintenance activities, unplanned breakdowns, and sub-optimal process conditions, there is insufficient capacity to treat the volume of oxalate extracted from the refinery Bayer process. Excess oxalate is stored in dedicated oxalate storage ponds located in the Residue Storage Area or in two oxalate storage tanks in the Clarification area. The proposed third Bioreactor unit will provide Alcoa with additional oxalate destruction capability for surplus oxalate management and provide capacity for additional oxalate generation due to predicted increases in the organic levels in future bauxite supply. 3. Overview of Oxalate Bioremoval Facility Upgrade Project Alcoa proposes to install a third bioreactor unit and upgrade some associated equipment to increase oxalate destruction capacity by approximately 22.5 tpd, bringing the refinery’s total oxalate destruction capacity to approximately 130 tpd. The additional destruction capacity will reduce the reliance on oxalate storage facilities, outside of planned major outages of the oxalate destruction facilities.

3.1. Project schedule Construction of a third bioreactor unit involves installing new equipment and upgrading existing equipment, as detailed in Section 3.2. Construction is anticipated to begin in Quarter 3 2020 and the third bioreactor unit is projected to be online and operating by mid to late 2021.

3.2. Infrastructure and equipment The proposed third bioreactor unit infrastructure, as it relates to Prescribed Activity Category 46 (Bauxite refining), is detailed in Table 1 below and shown in the engineering layout drawing in Appendix 1. Table 1: Proposed Oxalate Bioremoval Facility - third bioreactor unit - Category 46 infrastructure

Infrastructure Site Plan Reference Prescribed Activity Category 46 Bauxite is refined using the Bayer Process to produce alumina for export. The Bayer Process produces a build-up of sodium oxalate in the liquor stream that is currently destroyed (oxidised) in the oxalate kiln or at the Oxalate Bioremoval Facility through two continuous bioreactor units, or contained either within a tank or tanks at the refinery or within dedicated RSA oxalate storage ponds. It is proposed to upgrade existing Oxalate Bioremoval Facility infrastructure to include a third bioreactor unit to complement existing oxalate treatment. 1 Oxalate Bioremoval Facility upgrade incorporating:

• Bioreactor tank, cooler and associated pipework connection to existing infrastructure

• Bioreactor tank underflow pump and nutrient pumps • Wet scrubber system • Extension of existing secondary containment bunding • Upgrades to bioreactor feed pumps, freshwater

overflow pumps, cooling tower discharge pump, oxalate

Oxalate Bioremoval Facility Engineering layout drawing Oxalate Destruction Building PIN00052 SK-1, see Appendix 1.


repulp pumps, scrubber discharge pump and oxalate booster pump

Engineering design of the third bioreactor unit is currently in progress and there may be minor variations in the location, sizing and number of equipment items. Changes are not expected to impact the nature or quantity of emissions, discharges or wastes. Table 2 below details the proposed installation of new equipment. Table 3 describes the modifications to existing equipment proposed as part of the project works. Table 2: Proposed new equipment to be installed for Oxalate Bioremoval Facility third bioreactor unit.

Equipment Description Quantity

Electric Screw Compressor – No. 04 Air Blower 1

Air to Bioreactor 3 Flow Meter 2

Bioreactor Feed Pump Compact Screen Box 2

No.03 Bioreactor Cooler 1

No.03 Bioreactor Underflow Pumps 2

Unit 3 Bioreactor Slurry to Cooler Flow Meter 1

Unit 3 Bioreactor Slurry to Product Tank Flow Meter 1

No. 03 Bioreactor Tank - Flat Bottom Floor 1

No.03 Bioreactor Tank Agitator 1

Oxalate to Unit 3 Bioreactor Feed Flow Meter 1

No.04 Defoamant Pump 1

No.04 Nitrogen Pump 1

No.04 Phosphorus Pump 1

No.04 Magnesium Pump 1

No.03 Bioreactor Vent Scrubber 1

No.03 Scrubber Vent Stack 1

No.03 Scrubber Induced Draft Fan 1

CO2 to Bioreactor 3 Flow Meter 1

Bioreactor Cooler 3 Water to Cooling Tower Flow Meter 1


Table 3: Proposed Oxalate Bioremoval Facility equipment upgrades

Equipment Quantity Upgrade Activity

Cooling Tower Discharge Pump 2 Motor & Pump Impeller Upgrade

Bioreactor Feed Pumps 2 Pulley Upgrade

Fresh Water Overflow Pumps 2 Motor & Pump Impeller Upgrade

Oxalate Repulp Pump 1 Motor Upgrade

Oxalate Booster Pump 1 Motor Upgrade

Scrubber Discharge Pump 2 Pulley Upgrade

4. Legislative Context

4.1. Part IV of EP Act Pinjarra Refinery operates under Ministerial Statement 646 (Pinjarra Refinery Efficiency Upgrade Pinjarra). The proposed project scope does not require any alterations to the conditions, key characteristics or authorised extent described in Ministerial Statement 646.

4.2. Contaminated sites The Premises (including the Oxalate Bioremoval Facility) has an existing classification of ‘Possibly contaminated – investigation required’ under the Contaminated Sites Act 2004 (CS Act). Construction and operation of the proposed third bioreactor unit is not expected to impact ongoing processes under the CS Act.

4.3. Other relevant approvals 4.3.1. Planning approvals

The project scope to install a third bioreactor not does not require planning approval.

4.3.2. Department of Water and Environmental Regulation (Water)

The project scope to install a third bioreactor not does not require any water related approvals from the DWER.

4.3.3. Department of Jobs, Tourism, Science and Innovation


The Alumina Refinery (Pinjarra) Agreement Act 1969 and Alumina Refinery Agreements (Alcoa) Amendment Act 1987 apply to the Premises. These agreement acts do not require any additional or other approvals in relation to the proposed project scope.

4.3.4. Department of Mines, Industry Regulation and Safety

The project scope to install a third bioreactor will require review and amendment of the site Dangerous Goods Licence (DGS004240) to include the additional volume of liquor in the proposed bioreactor and associated pipework. This will be done via a separate application to the Department of Mines, Industry Regulation and Safety.

4.4. Part V of the EP Act 4.4.1. Amendment notices

The most recent licence amendment notice (Amendment Notice 4) was received on 28 August 2018, and relates to the alteration of the scope of works for the residue Filtration facility project (deletion of emergency containment pond requirements).

4.4.2. Compliance history

Pinjarra Refinery has had regular inspections by DWER representatives. The last inspection on 22 January 2016, did not identify any licence breaches or compliance issues. As required by the conditions of the Pinjarra Refinery environmental licence, Alcoa completes an annual audit of compliance to licence conditions report and submits the report each year via the Annual Audit Compliance Report (AACR) process. The last identified non-compliance was reported in the 2017 AACR. Pinjarra refinery has received no complaints in relation to the Oxalate Bioremoval Facility.

4.4.3. Noise impact assessment

Alcoa has undertaken a study into potential noise impacts associated with the installation of a third Bioreactor unit. The findings of this study are detailed in the Wood Report in Appendix 2. The report concluded the proposed upgrade to the Oxalate Bioremoval Facility will not contribute measurably to the existing noise levels at nearby receptors, and the predicted noise from new and modified equipment does not contribute to an exceedance of assigned noise levels. As has been previously discussed with DWER, on a broader scale Alcoa may not comply with Environmental Protection (Noise) Regulations 1997 (Noise Regulations) at certain receptors under worst-case meteorological scenarios. Alcoa is implementing a noise management program to reduce the likelihood of non-compliance with noise regulations at these receptors.

4.4.4. Clearing of native vegetation

Clearing of native vegetation in Western Australia requires a permit from DWER unless exemptions apply. No native vegetation clearing is proposed for this project. 5. Consultation


Alcoa has discussed the proposed project with Shire of Murray. The project will be also be discussed with the Pinjarra Community Consultative Network at the next scheduled meeting and by email communication. 6. Location and Siting 6.1. Siting context Pinjarra Refinery is located at the western edge of the Darling Scarp on land zoned as ‘Industry’ within in the Shire of Murray, in the Peel region approximately 95km south of Perth, Western Australia. The Pinjarra refinery is located approximately 5.5km east of the Pinjarra town site on land owned by Alcoa (Figure 2). The surrounding land-use is predominantly rural, with most of the region between South Western Highway and the Darling Scarp cleared of native vegetation. The major agricultural activities in the region are beef cattle and sheep grazing.

Figure 2: Alcoa Pinjarra Refinery showing premises boundary The Oxalate Bioremoval Facility is located on the north-eastern edge of the refinery as shown in Figure 3. The proposed location of the third bioreactor unit will be located within the existing licenced premises to the north of the existing bioreactors as shown in Figure 4.


Figure 3: Location of the existing Oxalate Bioremoval Facility within the refinery

Figure 4: Location of the proposed third bioreactor unit within the Oxalate Bioremoval Facility


6.2. Residential and sensitive premises The distances to residential and sensitive receptors are detailed in Table 4. Table 4: Receptors and distance from activity boundary Sensitive Land Uses Distance from Prescribed Activity Towns Pinjarra – approx. 6.2km south west

Dwellingup – approx. 11.8km south east Note: Distances are measured from the Oxalate Bioremoval Facility to the boundary of the respective town sites as measured on Alcoa’s Geographic Information System

Receptors As measured from the boundary of the Oxalate Bioremoval Facility depicted in Figure 3: R1 – (Approximately six Dwellings) - Approx. 5 km south R2 – (Single Dwelling) Approx. 2 km north east R3 – (North Pinjarra, Multiple Dwellings) Approx. 5.8 km north west R4 – (Petrol Station, Single Dwelling) Approx. 6.8 km west north west R5 – (Pinjarra, township, Multiple Dwellings) Approx. 6.7 km west Location of receptors in relation to Pinjarra Refinery are shown on Figure 5.

Figure 5: Location of nearest receptors in relation to Pinjarra Refinery. 6.3. Specified ecosystems Specified ecosystems are areas of high conservation value and special significance that may be impacted as a result of activities at or emissions and discharges from Pinjarra Refinery. The distances to specified ecosystems in respect of the existing Oxalate Bioremoval Facility are shown in Table 5.


Environmental values are obtained by using Alcoa’s Geographic Information System with data from Shared Location Information Platform (SLIP) Public Imagery and Maps Service datasets. Table 5: Locations of specified ecosystems in relation to Pinjarra Refinery Oxalate Bioremoval Facility Specified ecosystems Distance from the proposed Oxalate Bioremoval

Facility third reactor unit within the refinery Threatened and Priority Flora Declared Rare Flora area synaphea stenoloba located

approximately 5.7km north west

Waterways Conservation Act 1976 - Peel Inlet Management Area

Peel Inlet Management Area located approx. 6.9km west north west

Geomorphic Wetlands Swan Coastal Plain (management) – Conservation category

2.5km east and 3.4km north west

Geomorphic Wetlands Swan Coastal Plain (management) – Resource Enhancement category

3.8km north west and 3.1km south east

Geomorphic Wetlands Swan Coastal Plain (management) – Multiple Use category

200m east, 1km north and 2.5km south west

Waterways Conservation Act 1976 waterways conservation area – Peel Inlet Management Area

Peel Inlet Management Area located approx. 6.9km west north west

Peel-Harvey EPP The Peel-Harvey EPP area incorporates all parts of the Premises and surrounding areas.

Threatened (Declared Rare) Flora Declared Rare Flora area synaphea stenoloba located approximately 5.7km north west

Priority Flora Declared Rare Flora area synaphea stenoloba located approximately 5.7km north west

Priority 1 Public Drinking Water Source Area – South Dandalup Pipehead Dam Catchment Area

Located approx. 2.1km east and uphill toward the Darling scarp

6.4. Groundwater and surface water sources

The Pinjarra Refinery Long Term Residue Management Strategy (LTRMS) summarises hydrology in proximity to the Premises. The LTRMS is available at www.alcoa.com.au.

The Pinjarra site lies at the eastern edge of the Perth Basin, the major groundwater feature of the Swan Coastal Plain. Near the residue areas, the Guildford Clays dominate the shallow soil type. These low permeability clays form a barrier to vertical and horizontal groundwater flow. Pathways for local groundwater movement are provided by the presence of sandy zones, dissected clays and lateritic intrusions. The Guildford Clays are underlain by sands and clayey sands in the Yoganup Formation. Beneath this lies the Leederville Formation, whose top layer is often identified by a layer of dark silty clay or shale which forms an effective hydraulic barrier. In some locations, however, this layer is not present and the Yoganup and upper Leederville Formations are hydraulically continuous. The upper section of the Leederville Formation comprises gravelly silts, clays, siltstones and silty or clayey sands. Underlying the Leederville


Formation is the Cattamarra Coal Measures, part of the Cockleshell Gully Formation, which extends from Rockingham in the north to Kemerton in the south.

Regional surface hydrology is strongly determined by the underlying geology and regional topography. The Murray River is a major drainage pathway for the region and is fed by sub-catchments draining the foothills. The Murray River ultimately drains into the Peel-Harvey Estuary. Surface flows ultimately drain into the Murray River. The two creek lines directly associated with the refinery and residue area are Oakley Brook to the south and Barritt Brook to the north. During construction of the refinery and residue area, surface water dams were created for both brooks with the water being used for refinery purposes. Alcoa has two structures at Oakley Brook; the Oakley Brook Detention Dam and the Lower Oakley Pumpback Dam, which are designed to hold surge following rainfall events. Overflow from these dams continues on its original course. The overflow from Barritt Brook was redirected around the northern boundary of the residue area and in 1996 redirected into an Alcoa created clay borrow pit.

Overflow from Barritt Brook is redirected to lands west of the refinery and residue storage area and drains to Lake Kulinup, an artificial body of water to the west of RSA5 formed from a clay borrow area, or to the Murray River. Within Alcoa’s landholdings, there are no other users of surface and groundwater.

Table 6 provides a description of groundwater and water sources.

Table 6: Groundwater and water sources in relation to Pinjarra Refinery oxalate Bioremoval Facility

Groundwater and water sources

Distance from Oxalate Bioremoval Facility

Environmental value

Murray River Approx. 6.8 km Within the Peel-Harvey EPP area and discharges into the Peel Estuary

South Dandalup River

Approx. 3.2 km With the Peel-Harvey EPP area and discharges into the Murray River north west of the Premises

Major tributary – Tate Gully

Approx. 7 km Tributary of the Murray River

Major Tributary – Oakley Brook

Approx. 4.5 km Tributary of the Murray River Lower Oakley Pumpback and Oakley Brook Detention Dam are sources for the refinery process water supply. Oakley Brook also provides some stock water on private land downstream of the refinery.

Major Tributary - Barritt Brook

Approx. 1.7 km Barrit Brook Detention Dam is a source for refinery process water supply. Barritt Brook also provides some stock water on private land downstream of the refinery.

Drains Approx. 300 m Drains in paddocks to the north adjacent to the Oxalate Bioremoval facility may discharge to the Barrit Brook Detention Dam.

Groundwater Typically <5 m BGL (superficial aquifer)

Localised elevated concentrations of alkaline salts have been detected within the Pinjarra Refinery and residue storage area in the upper and lower superficial formations since the 1980s, relating to historical construction and operational practices and engineering standards at that time.


Superficial Aquifer: 0-15 m BGL

Superficial aquifer: Source for local and regional water supplies for potential domestic, stock and irrigation purposes.

Leederville Aquifer: 10-120m BGL

Leederville aquifer: Source for local and regional water supplies for potential domestic, stock, irrigation and industrial purposes.

Cattamarra Aquifer: 3-120m BGL

Cattamarra aquifer: Primary source of the process water and potable water supplies. Contains groundwater resources that may be accessed by other users in the region for domestic, stock, irrigation and industrial water supplies.

6.5. Other site characteristics

Other relevant factors and receptors are shown in Table 6.

Table 6: Other landscape features, relevant factors or receptors.

Other receptors or areas of concern

Location

Peel-Harvey Environmental Protection Policy (EPP)

The Peel-Harvey EPP area incorporates all parts of the Premises and surrounding areas

6.6. Soil type

The geological context of the premises is described in the LTRMS; the shallow superficial formation comprises clay, clayey sand and sand (Guildford Clay and Yoganup Formation most dominant) up to 20m thick. The Leederville Formation is encountered at 20 to 30 m and extends approximately 120 m beneath the RSA. The upper Leederville Formation is composed of silts, clays, siltstones and silty or clayey sands. The deeper Cattamarra Coal Measures are characterised by sandstone, siltstone, shale and some minor coal.

6.7. Meteorology

The LTRMS provides a summary information on climate and weather for the localised Pinjarra area. Pinjarra has a Mediterranean type climate characterised by warm dry summers and mild wet winters with temperatures similar to those recorded in Perth. Rainfall through the Peel Region is seasonal with the majority of rainfall received during the winter months (June to August). The long-term average annual rainfall at the Pinjarra Post Office (90 years of data) is 944 mm. The winds at Pinjarra are controlled by synoptic weather patterns and local features such as the topography and sea and land breezes. The location of the Premises as the base of the Darling escarpment impacts on larger scale winds creating effects such as strong easterly ‘foothill’ winds, wind reversal, and wind channelling.


7. Risk Assessment and Controls

7.1. Identification of potential impacts

Identification of potential emissions, pathways and receptors, at different stages of the project schedule are set out in Table 7. Potential impacts were risk assessed using Alcoa risk assessment criteria as included in Appendix 3.

Aspects and impacts that flagged as having a moderate or higher risk, or were of deemed to be of significance, have been assessed in detail, with discussion about controls to be implemented to control and mitigate potential risks. These items are discussed in sections further below.


Table 7: Identification of key emissions and the potential for impacts during construction, commissioning and operation of third bioreactor.

Risk Events Risk Assessment Continue to detailed

risk assessment

Reasoning Sources/Activities Potential

emissions Potential receptors Potential pathway

Potential adverse effects Proposed Controls Consequence Likelihood Risk

Rating

Construction, mobilisation

and positioning of

infrastructure

Use of mobile equipment and lifting equipment. Earthworks to construct bunding and roads over existing sealed areas.

Noise

Pinjarra town site (west) – approx. 6.6km Fairbridge (north) – approx. 4.5km Private residences located between 2.4km to 6.8km

Air/wind dispersion

Regulated noise level exceedance for environmental noise Amenity impacts Community complaints

Construction Management Plan to include noise management in accordance to AS2436-2010 Guide to noise and vibration control on construction, demolition and maintenance sites section 4. Construction planned for the daytime only. Pre-fabrication of some equipment and infrastructure offsite.

Minor Unlikely Low No

Noise impacts are negligible during construction activities and construction works are to only occur during the day time hours. If there is any need to undertake construction activities outside of these hours, a Noise Management Plan will be developed.

Civil works may generate minor dust from construction of roads and bunding

Dust


Air/wind dispersion

Dust level exceedance >260 ug/m3 at High Volume Samplers Health and amenity impacts

Dust management to be included in the Construction Management Plan. Environmental Awareness Training.

Insignificant Unlikely Low No

Dust impacts are negligible during construction considering the location, scale, size of the scope of works and distance to nearest receptor. Dust is managed internally through daily monitoring of High Volume Samplers and current Environmental Licence conditions set out in L5271/1983/14.

N/A

Point source odour and gaseous emissions to air


Air/wind dispersion N/A N/A N/A N/A N/A No Not applicable during

construction activities.

N/A Point source mercury emissions to air


Air/wind dispersion N/A N/A N/A N/A N/A No Not applicable during

construction activities.

N/A Wastewater Discharges

Superficial Aquifer Cattamarra Aquifers Brooks – 1.7km to 5.1km Streams and creeks – 0.1km to 10.0km Murray River – 6.8km

Land infiltration to groundwater and/or surface water

N/A N/A N/A N/A N/A No Not applicable during construction activities.

N/A

Contaminated or potentially contaminated stormwater or soil/groundwater



N/A N/A N/A N/A N/A No Not applicable during construction activities.



risk assessment




Rating

Refuelling of equipment and storage of chemicals used for construction activities

Waste and leachate



Impacts on the beneficial use of groundwater and surface water Adverse health effects to ecosystem Health and amenity impacts

Construction Management Plan to include refuelling and servicing of equipment, incident management and storage of chemicals.


Spills from chemical storage or refuelling of equipment would be expected to not impact unsealed areas. Chemicals to be stored in a workshop area and refuelling to occur over sealed areas. In the event of a spill to sealed areas it would be low in volume and confined to a small area with immediate clean up through internal incident management procedures.

Commissioning and

operation of the third

bioreactor unit

Normal operation of equipment and new equipment upset conditions creating noise (issues with pumps for example)

Noise


Air/wind dispersion

Regulated noise level exceedance for environmental noise Amenity impacts Community complaints

Equipment specification to vendors including verification monitoring performed by vendor. Alcoa Engineering Standard Noise Levels of Stationary Equipment 83dB(A) at 1m for new equipment.

Moderate Unlikely Medium Yes

Noise Consultants engaged to predict noise impacts through noise modelling. Refer to section 7.2 for assessment.

Spilled oxalate within the bund dries out creating oxalate dust

Dust


Air/wind dispersion

Dust level exceedance >260 ug/m3 at High Volume Samplers Health and amenity impacts

Operating procedures and tank level management systems. Spill clean-up and incident response procedures. Housekeeping.


The volume of oxalate able to be spilled into bunds an generate dust too small to impact receptors over a large distance. Environmental licence does not permit storage of oxalate outside of tanks of approved oxalate storage facilities. Spilled materials to be cleaned up as per incident response procedures.

Wet scrubber water supply issues (nozzle blockages, pump supply failure or control valve failure) or air flow supply issues (incorrect set up of line, knife gate valve closed or packing restricted)

Point source odour and gaseous emissions to air


Air/wind dispersion

Health and amenity impacts

Bioreactor tanks with lids and vents to capture and treat odour and gaseous emissions through a wet scrubber system before exiting through the stack. Feed interlocks on the water scrubber flow rate and on the ID fan status Process control system logic and alarms

Minor Unlikely Low Yes

Gaseous emissions and odour assessment conducted by Alcoa, refer to section 7.3 for assessment.



risk assessment




Rating

Normal operation of equipment Trace amounts of mercury contained in oxalate material emitted via vapours from bioreactor tanks

Point source mercury emissions to air


Air/wind dispersion

Health and amenity impacts

Bioreactor tanks with lids and vents to capture and treat gaseous emissions through a wet scrubber system before exiting through the stack Feed interlocks on the water scrubber flow rate and on the ID fan status Process control system logic and alarms

Insignificant Rare Low No

Mercury emissions to air from bioreactor tanks are insignificant. Studies undertaken by Alcoa and confirmed through independent assessment indicates mercury remains in the liquor circuit and would report to the Residue Storage Area. Operation of bioreactor tanks will have no measurable effect on the level of mercury emissions to air (Appendix 4).

N/A Wastewater Discharges



N/A N/A N/A N/A N/A No Not applicable during commissioning or operation.

Pump failure, spills, loss of containment, leaking equipment, pipes, tanks

Contaminated or potentially contaminated stormwater




All equipment within bunded area in accordance with Dangerous Goods Regulations Sumps within bunded areas to redirect spilled material to the feed prep tank or product tank Sealed areas surrounding the facility Maintenance inspections (Yearly MOHs and internal vessel inspection of liners) and operating procedures Bottom of Bioreactor tank will be manufactured from stainless steel Water/wet commissioning of equipment to identify leaks and resolve them prior to operation

Minor Rare Low Yes

A Dangerous Goods consultant has been engaged for the project, refer to section 7.4 for the assessment. Pinjarra refinery operates in a closed-circuit stormwater system. Any loss of containment event contained with the refinery will report to the RSA and liquids are re-used in other parts of the process. Loss of containment events at the facility are likely to be relatively small in volume and confined to a small area with immediate clean up through internal incident management procedures. Initial commissioning of equipment will be completed with water, any leaks or issues identified will be rectified prior to the operation phase. Loss of containment events are not expected to access surface water or groundwater..

Biomass transfer into bioreactors leaks of pipework or equipment

Waste and leachate




All equipment within bunded area in accordance with Dangerous Goods Regulations Permanent built-in pipework into the bioreactor Water/wet commissioning of equipment to identify leaks and resolve them prior to operation

Minor Rare Low Yes

7.2. Noise emissions Pinjarra Refinery noise emissions have been shown to occasionally exceed assigned boundary levels during worst case weather conditions at receptor locations to the south and to the north east of the refinery. The frequency and magnitude of exceedances are dependent on meteorological conditions, with levels higher under calm/inversion conditions and light downwind conditions. Tonality has been observed on occasion at some locations and the presence of tonality incurs a +5dB(A) penalty to the measured noise level, under the Environmental Protection (Noise) Regulations, resulting in an increased magnitude of the exceedance.

Noise consultants (Wood) were engaged to perform a desktop study to predict noise emissions from the third bioreactor unit and associated equipment upgrades. Predicted noise levels at the receptors were modelled using worst-case meteorological conditions and compared to the approved regulated noise levels at each receptor. The sound power levels for the equipment modelled has been used from previous survey results obtained by the noise consultant at the Oxalate Bioremoval Facility and Pinjarra Refinery. The noise sources and corresponding sound power levels are shown in Table 8.

Table 8: Equipment sound power levels (Wood Noise Report, Appendix 2)

Source Construction Type Sound Power Level dB(A)

Air Blower No.4 New 101.9

Bioreactor Agitator No.3 New 104.8

Bioreactor Underflow Pump No.3 New 94.8

Scrubber Induced Draft Fan No.4 New 100.8

Cooling Water Discharge Pump Upgrade 83.3

Oxalate Booster Pump Upgrade 85.7

Oxalate Repulp Pump Upgrade 86.1 The predicted noise levels assessed at the noise receptor locations are shown in Table 9.

Wood noted in the report that the contribution of the upgraded Oxalate Bioremoval Facility to noise levels received at the most affected receptor is more than 13 dB below the contribution of the existing refinery. The noise level predictions demonstrated that the upgraded facility would have no discernible impact on received noise levels at nearby receptors.

Table 9: Worst-Case Predicted Noise Levels from the Pinjarra Refinery, Oxalate Bioremoval Facility and Oxalate Bioremoval Facility upgrade (source: Rpt01-1404084-Rev0-12Nov19)

Noise Receiver

Assigned Regulated

Noise Level LA10

dB(A)

Existing modelled noise levels dB(A)

Predicted noise levels dB(A) Total

Refinery Emissions Difference

after Oxalate

Bioremoval Facility upgrade

dB(A)

Existing Pinjarra Refinery

Base Model

Existing Oxalate

Bioremoval Facility

Base Model

Predicted Oxalate

Bioremoval Facility

Upgrade

Predicted Pinjarra Refinery, Oxalate

Bioremoval Facility and

Oxalate Bioremoval

Facility Upgrade

R1 36 35.9 11.6 13.1 35.9 + 0.01

R2 35 40.7 26.4 27.6 40.8 + 0.05

R3 35 33.5 12.6 14 33.5 + 0.01

R4 37 33.3 9.5 11.3 33.3 + 0.01

R5 35 34.1 8.5 10.5 34.1 + 0.01 Wood predicted that noise from Pinjarra Refinery would be expected to increase between 0.01 and 0.05dB(A) at nearby receptors as a result of the installation of the third bioreactor unit. As part of the design of the third bioreactor unit the new proposed agitator drive will be designed to meet the requirements outlined in Alcoa Engineering Standard Noise Levels of Stationary Equipment. The standard states all new equipment should not exceed 83dB(A) at one-meter distance, and that this is to be tested and verified by the vendor prior to commissioning. Additionally, Alcoa will install acoustic enclosures on the existing two agitator drives. These measures should ensure there is no measurable increase in noise levels at nearby residential receptors. Construction activities will occur between 7:00am and 7:00pm, Monday to Saturday. Construction activities are unlikely to occur Sundays or Public Holidays. Most equipment will be fabricated offsite in a workshop to limit noise impacts. The project construction management plan will include noise management. If there is any need to undertake construction activities outside of these hours, a Noise Management Plan will be developed.

7.3. Odour and gaseous emissions

A desktop study was undertaken to evaluate the potential for odour and gaseous emissions from the third bioreactor unit. Ammonia and Volatile Organic Compounds (VOCs) were determined to be the predominant emissions from the Oxalate Bioremoval Facility.

Air emissions from the existing bioreactor tanks are passed through a wet scrubber before being released to atmosphere. The proposed third bioreactor tank will also include a wet scrubber.

Based on results from previous air emissions monitoring from the existing Oxalate Bioremoval Facility, the contributions of ammonia and VOC emissions to the overall refinery emissions inventory from a third bioreactor tank have been estimated (Table 10). The impacts from air emissions from the upgraded Oxalate Bioremoval facility are expected to be minimal (less than 0.05%).

Table 10: Predicted contribution of 3rd Bioreactor Unit to ammonia and VOC emissions to air.

Emission Total Refinery Emissions (incl. current Bioremoval facility)

Total Refinery Emissions (with Bioreactor 3 Upgrade)

Bioreactor 3 Upgrade contribution

% of Refinery total

Ammonia (kg/a) 24941.98 24951.18 + 9.2 0.03%

VOC (tpa) 144.70 144.72 + 0.03 0.02%

With respect to odour emissions, Alcoa has considered the Guideline: Odour Emissions, June 2019 published by DWER. The guideline requires a screening analysis to be performed for impacts to nearby receptors, and if a potential impact is noted, a detailed odour analysis to be prepared. Screening distances for Bauxite Refining premises categories are determined as ‘case-by-case’, and the Odour Emissions guidelines recommends a detailed odour analysis be undertaken.

The requirement for a detailed odour analysis was discussed with representatives from the DWER during a scoping meeting on 6 January 2020, in which it was agreed that a detail odour analysis would not be required for this project scope, given the insignificant change to VOC emissions from the installation of a 3rd bioreactor unit and previous odour analysis conducted by Alcoa for the Pinjarra Refinery.

Under a previous works approval condition for construction of RSA10 (W5206/2012/1) field odour surveys were undertaken between August 2014 and February 2016. The surveys aimed to establish a baseline odour survey for the refinery and residue storage area (RSA) and to determine if the commissioning of RSA10 had resulted in increases to odour levels downwind of the Refinery and RSA. The methodologies for these odour assessments were developed in conjunction with the DWER (formerly the DER), and final reports were submitted as required by the works approval conditions. Both the baseline and post-commissioning surveys observed relatively low frequency of refinery odours being positively identified during the

assessment. This indicates that odour from the refinery is a rare occurrence therefore has a low impact on nearby receptors.

Odour emissions from the refinery have not been noted to have a significant impact to nearby receptors. The construction and operation of a third bioreactor unit is predicted to have an insignificant increase to odour emissions from the refinery.

7.4. Discharges to land The Oxalate Bioremoval Facility includes process tanks contain sodium oxalate slurry and sodium oxalate solution and the storage of defoamer and nutrients (typically magnesium sulphate, phosphorous and nitrogen).

A third bioreactor tank will be constructed in the same manner as the existing bioreactor tanks.

Materials within the new equipment and any changes to existing equipment will be managed in accordance with the Dangerous Goods Safety Act 2004 and the Dangerous Goods (Storage and Handling of Non-explosives) Regulations 2007.

All chemical storage associated with the proposed work will also meet requirements of Pinjarra’s EP Act Licence (L5271/1983/14) current at the time of installation.

Alcoa maintains a Dangerous Goods Licence (DGS004240) and will liaise with Department of Mines and Industry Regulation and Safety (DMIRS) to update the licence volume for Class 8 materials prior to commissioning the third bioreactor tank. Amendment to the Dangerous Goods Licence will be supported by a review by an accredited Dangerous Goods Consultant. The consultant will review the design of the proposed Bioreactor unit against relevant codes of practice such as Australian Standard 3780 Storage and handling of Corrosive Substances.

The Dangerous Goods consultant review will consider bunding requirements. The proposed bund extension is depicted on Figure 3. The bund will be designed to contain at least 110% of the largest storage vessel or interconnected system, and at least 25% of the total volume of all substances stored in the Facility, as per the site environmental licence.

Outside of the bunded area, the surface is coated with bitumen seal and graded to towards drains for the capture of stormwater runoff. In the event that a loss of containment occurred, and sodium oxalate solution or other Bayer process liquids escaped the bunded area, they would be contained by the refinery stormwater system network, which ultimately reports to RSA.

Alcoa has procedures to manage loss of containment incidents to minimise the likelihood of harm to the environment.

8. Reference List Department of Water and Environmental Regulation. (2019). Guideline: Industry Regulation Guide to Licensing. Retrieved from https://www.der.wa.gov.au/our-work/licences-and-works-approvals/publications. Department of Water and Environmental Regulation. (2019). Guideline Odour emissions. Retrieved from https://www.der.wa.gov.au/our-work/licences-and-works-approvals/publications Pinjarra Refinery DER Licence L5271/1983/14. http://cds101.alcoa.com/Environment/AUACDS-2056-803.pdf Ministerial Statement 646 for the Pinjarra Efficiency Upgrade. http://cds101.alcoa.com/Environment/AUACDS-2056-805.pdf

https://www.der.wa.gov.au/our-work/licences-and-works-approvals/publications




http://cds101.alcoa.com/Environment/AUACDS-2056-803.pdf

http://cds101.alcoa.com/Environment/AUACDS-2056-805.pdf

9. Appendix Appendix 1 – Diagram of Oxalate Bioremoval Facility with new

equipment Appendix 2 – Wood Noise Report Appendix 3 – Alcoa Risk Rating and Risk Criteria tables Appendix 4 – Dr Peter May. Effect of Oxalate Bioreactor on Mercury

Emissions at the Pinjarra Refinery, 2011

Appendix 1

Diagram of Oxalate Bioremoval Facility with new equipment

resourceschemicalsenergy

43kL TANK(MgSO4)

MAGNESIUM

60kL TANK

(AGSTREAM)

PHOSPHOROUS

60kL TANK

(FLEXI-N)

NITROGEN

SUMP

AREA

EXISTING ROAD WAY

B

3

A

B

1

2

3

4

5

6

7

8

1100

SUMP

AREA

SCRUBBERS

EXISTING

UNDERFLOW PUMPS

EXISTING PRODUCT TANK

Project No:-

ABN: 61 001 279 812

PH: +61 8 9278 8111

240 St George Tce Perth WA 6000

GA11/02/20

G ALDEGHERI

M69

PJ037B

15/01/201:100

D CASELLO

NEW BIO-REACTOR UNIT 03

OXALATE DESTRUCTION BUILDING

PJ097071

RW110000

PIN00052

ALCOA PROJECT NUMBER:

N

LOCATION PLAN

N

DRAWING

THIS

PJ097076

PJ097075

PJ097074

PJ097073

PJ097072

(EXIST)

� 01 AIR BLOWER

PJ037B-BRB001

(EXIST)

� 02 AIR BLOWER

PJ037B-BRB002

(EXIST)

� 03 AIR BLOWER

PJ037B-BRB003

VESSLE (EXIST)

� 01 CO2 STORAGE

PJ037B-COV001

(EXIST)

01 BIO REACTOR COOLER �

PJ037B-OTC001

(EXIST)

� 02 BIO REACTOR TANK

PJ037B-BRT002

(NEW)

03 BIO REACTOR TANK

PJ037B-BRT003

�

(EXIST)

01 BIO REACTOR TANK

PJ037B-BRT001

�

(NEW)

VENT SCRUBBER

03 BIO REACTOR

PJ037B-BVS003

DRAFT FAN (NEW)

03 SCRUBBER INDUCED

PJ037B-IDF003

TANK (EXIST)

� 01 BIO REACTOR PRODUCT

PJ037B-BPT001

(NEW)

� 03 BIO REACTOR TANK

PJ037B-BRT003

710

011

090

5750

2525

(NEW)

� 03 BIO REACTOR COOLER

PJ037B-OTC003

EXISTING BUND

EXTENT OF

8000

31400 O/ALL

23200 O/A KERB

CLEARANCE

6152

EXTENSIONBLOWER SLAB 4200x6200

(NEW)

04 AIR BLOWER

PJ037B-BRB004

(EXIST)

� 02 BIO REACTOR COOLER

PJ037B-OTC002

ISSUED FOR CHECKING

DRG. 3

ARRANGEMENT SEE REF.

FOR VENT SCRUBBER

DRG. 1

& ARRANGEMENT SEE REF.

FOR BIOREACTOR 3 PLAN

PUMPS UFP 031 & 032

TANK UNDERFLOW

NEW BIO-REACTOR

CABLE TRAY & PIPE SUPPORT PLAN, SECTIONS & DETAILSPJ097078

PIPE RACK EXTENSION PLAN, SECTIONS & DETAILS PJ097077

SUMP, FEED PREP & PRODUCT TANK PIPING SECTIONS

BIO-REACTOR 03 - VENT SCRUBBER PLAN & SECTIONS SITE PLAN

AIR BLOWER & CO2 PLAN, SECTIONS & DETAILS

BIO-REACTOR 03 - SECTIONS

BIO-REACTOR 03 - PIPING PLAN

PROPOSED BUND EXTENSION

NEW ROAD BOUNDARY (DESIGNED TBC)

15

A5

TANK (EXIST)

FEED PREPARATION

PJ037B-BFT001

�

NOTES

NOTES SEE REFERENCE DRAWING No.1

1. FOR GENERAL PIPING @ STRUCTURAL STEEL

BIOREACTOR 03 NUTRIENT DOSING P&IDPJ09674811

AIR BLOWER BRB004 & COV001 P&iDPJ09674710

BVS003 BIO REACTOR VENT SCRUBBERS P&iDPJ0967479

BRT003 BIO REACTOR TANK OXALATE DESTRUCTION P&iDPJ096746

HH H HOLLING

N FERNANDEZ

GAISSUED FOR CLIENT REVIEW20/02/20

REVIEWISSUED FOR

PROJECT REVIEW PRINT

1. Responsible Eng

NAME SIGN DATE

2. Design Team Ldr

3. Proj. Team Ldr

4. Area Process Eng

5. Area M,E,C/S,Eng

6. Asset Owners Rep

7.

8.

signatures imply approved as noted

comments to be signed and dated

non-approval to be explained via comment

ORIGIN

AL STORED ELECTRONIC

ALLY

CO

MPUTER PRODUCED DRA

WIN

G

No.

DRAWING TITLE

DATE REVISION RECORDM/FNo. DR. APP.CHK.SCALE

ALCOA OF AUSTRALIA LIMITED

DATE

A.C.N. 004 879 298

CATEGORY CODE

DESIGNED

DRAWN

UNIT CODE

EQUIPMENT LOCATION SYSTEM CODE

drawing without the consent of ALCOA OF AUSTRALIA LIMITED.

to others. Nor may photographs be taken of any article fabricated or assembled from this

Neither this drawing nor any information concerning it may be copied, exhibited or furnished

It is confidential and is given to you for a limited purpose and must be returned on request.

This drawing and all the information on it is the property of ALCOA OF AUSTRALIA LIMITED.

DRG. No. REFERENCE DRAWINGSCHECKED

DRAWING

DO NOT SCALE

DIMENSIONS ARE IN MILLIMETRES

SIZE

SHEET

NUMBER

REVISIONDRAWING NUMBER

A1

APPROVED

DESIGN

APPROVED

CUSTOMER

PROJECT TEAM LEADER

21/02/2020 9:22:49 AM

Z:\Shop_frt\PROJECTS\PIN00052\Drawings\Working\Mech_Pipe\PJ097071.DGN

Alcoa

01m 1m 2m 3m 4m 5m 6m 7m 8m 9m

GRAPHIC SCALE 1:100

10m

143F

CAR PARK N°1

N°2

CAR PARK

146B2

146B1

146M

146A

146C

144

COMPOUND

STORES

148

143N

143S

143

154

150T 150A

141D

147

141

N°1

K�LN

141E

PST

37

37D

37

STORE COMPOUND

CONSTRUCT�ON

37F

X

37X

37A

N°2

K�LN

35A

35W

35

35B

35E

35E5

149W

8B

130

8C

149B

35D

11

14

12

13

34

35D

24

22

23

21

35F

35FX

33

32

31

35J

35H

54

52

53

55

35C

44

14

42

43

45

12

13

15

11

35H

35C

35M

34

32

33

35

24

22

23

25

21008D

30E

46.37

46.22

46.1546

.00

45.63

141A

35J 35J

35J

135A

155Y01

155

Y02

155Y05

155

Y03

155

Y04

155Y06

155

Y08

155

Y07

155T2

155

Y11

155Y12 155Y13

155T3

155Y14155Y15155Y16

155T1

156W3

156W2156W1

155C

155B

157A

157B

157D

157E

157T1

157C

155P01

155P02

156

A

156B

155

Y09

155

Y10

156Y04

156Y03

156Y06

156

Y02

156

Y01

155S

370

156

Y05

37C

51 41 31

HEL� PAD

POND BOUNDARY FENCE

141B

37B

S6

S10D

141S

141F

141I

141C

S25

S24 S4

005D

Appendix 2

Wood Noise Report

www.woodplc.com

Specialist Technical Services

Vibration, dynamics and noise

PINJARRA BIOLOGICAL OXALATE

DESTRUCTION PLANT UPGRADE NOISE

ASSESSMENT

ALCOA OF AUSTRALIA

Rpt01-1404084-Rev0-12Nov19

http://www.woodplc.com/

http://www.woodplc.com/

Alcoa of Australia

Pinjarra Biological Oxalate Destruction Plant Upgrade Noise Assessment

Rpt01-1404084-Rev0-12Nov19

Page I

DOCUMENT CONTROL & REVIEW

INFORMATION

Client: Alcoa of Australia

Client Contact: Amir Sharafzadeh

VDN Contact: Corey Berryman

VDN Office: Perth

VDN Job No: 1404084

VDN Document No: Rpt01-1404084-Rev0-12Nov19

Rev Date Description Prepared Reviewed Approved

Proj Manager Client

A 29 Oct 19 Issue for review C Berryman J McLoughlin

0 12 Nov 19 Issue for use C Berryman J McLoughlin

Item Page Section Comments

* Use after Rev. 0

Alcoa of Australia


Rpt01-1404084-Rev0-12Nov19

Page II

Disclaimer

This Introduction and Scope of Works (Report) has been prepared for Alcoa of Australia by

Wood, based on assumptions as identified throughout the text and upon information and data

supplied by others.

The Report is to be read in the context of the methodology, procedures and techniques used,

Wood’s assumptions, and the circumstances and constraints under which the Report was

written. The Report is to be read as a whole, and sections or parts thereof should therefore

not be read or relied upon out of context.

Wood has, in preparing the Report, followed methodology and procedures, and exercised due

care consistent with the intended level of accuracy, using its professional judgment and

reasonable care. However, no warranty should be implied as to the accuracy of estimates or

other values and all estimates and other values are only valid as at the date of the Report and

will vary thereafter.

Parts of the Report have been prepared or arranged by Alcoa of Australia or third party

contributors, as detailed in the document. While the contents of those parts have been

generally reviewed by Wood for inclusion into the Report, they have not been fully audited or

sought to be verified by Wood. Wood is not in a position to, and does not, verify the accuracy

or completeness of, or adopt as its own, the information and data supplied by others and

disclaims all liability, damages or loss with respect to such information and data.

In respect of all parts of the Report, whether or not prepared by Wood no express or implied

representation or warranty is made by Wood or by any person acting for and/or on behalf of

Wood to any third party that the contents of the Report are verified, accurate, suitably qualified,

reasonable or free from errors, omissions or other defects of any kind or nature. Third parties

who rely upon the Report do so at their own risk and Wood disclaims all liability, damages or

loss with respect to such reliance.

Wood disclaims any liability, damage and loss to Alcoa of Australia and to third parties in

respect of the publication, reference, quoting or distribution of the Report or any of its contents

to and reliance thereon by any third party.

This disclaimer must accompany every copy of this Report, which is an integral document and

must be read in its entirety.

Alcoa of Australia


Rpt01-1404084-Rev0-12Nov19

Page III

EXECUTIVE SUMMARY

Wood was commissioned by Alcoa to undertake an environmental noise impact assessment of

the proposed upgrade to the biological oxalate destruction plant (BOD) at the Pinjarrra refinery.

The existing Pinjarra refinery noise model has been updated to include the biological oxalate

destruction plant upgrade. The model has been used to predict levels at the five selected noise-

sensitive receivers that have been used previously for environmental noise impact assessments

for the Pinjarra facilities. The noise levels at these locations were predicted using worst-case

night time meteorological conditions as suggested by the WA Department of Water and

Environment Regulation, Draft Guideline on Environmental Noise for Prescribed Premises and

compared to the prescribed noise levels at each selected location.

The contribution of the upgraded BOD to noise levels received at the most affected residential

receptor is more than 13 dB below the contribution of the existing refinery.

The noise level predictions demonstrate that the BOD upgrade will have no discernible impact

on received noise levels at noise sensitive receptors surrounding the refinery.

Alcoa of Australia


Rpt01-1404084-Rev0-12Nov19

Page IV

TABLE OF CONTENTS

1 INTRODUCTION ....................................................................................... 1

1.1 Model Objectives ........................................................................................................... 1

1.2 Applicable Documents ................................................................................................... 1

1.3 Project Design Documents ............................................................................................ 1

2 SUMMARY OF RELEVANT LEGISLATION ............................................. 3

2.1 Environmental Protection (Noise) Regulations 1997 .................................................... 3

1.1 Assigned Levels for Selected Receptors ...................................................................... 4

2.2 Adjustments for Intrusive Characteristics ...................................................................... 5

3 NOISE MODELLING METHODOLOGY .................................................... 6

3.1 Existing Noise Model ..................................................................................................... 6

3.2 Noise Model Program .................................................................................................... 7

3.3 Noise Model Algorithm .................................................................................................. 7

3.4 Selection of Meteorological Conditions ......................................................................... 7

3.5 Ground Topography....................................................................................................... 8

3.6 Acoustic Effects for Existing Structures ......................................................................... 8

3.7 Ground Absorption......................................................................................................... 8

3.8 BOD Noise Sources....................................................................................................... 9

3.8.1 Base Case .......................................................................................................................................................... 9

3.8.2 Air Blower ........................................................................................................................................................... 9

3.8.3 Bioreactor Tank .................................................................................................................................................. 9

3.8.4 Cooling Water ................................................................................................................................................... 10

3.8.5 Oxalate Repulp Tank ........................................................................................................................................ 10

3.8.6 Scrubber........................................................................................................................................................... 10

4 MODELLING RESULTS .......................................................................... 11

4.1 Noise Levels ................................................................................................................ 11

4.2 Tonality ........................................................................................................................ 11

5 CONCLUSION ......................................................................................... 12

APPENDIX A BOD MODELLED NOISE SOURCES ................................... A-1

APPENDIX B NOISE CONTOURS .............................................................. B-1

Alcoa of Australia


Rpt01-1404084-Rev0-12Nov19

Page 1

1 INTRODUCTION

Wood maintains an environmental noise model of the Pinjarra Refinery, located near Pinjarra in

the south west of Western Australia. The most recent iteration of the model was prepared in

March 20191.

Alcoa plans to upgrade the current Pinjarra Biological Oxalate Destruction plant (BOD) by

adding a third bioreactor. This report details the changes made to the environmental noise model

to represent the planned upgrade and presents an environmental noise impact assessment of

the upgrade in terms of its contribution to noise received at neighbouring residential receptors.

The Pinjarra refinery is located at the foot of a scarp, between the town of Pinjarra and the

Darling Range. The centre of the Pinjarra refinery is located approximately 7 kilometres east of

the Pinjarra town centre. The Pinjarra refinery extends approximately 4 km in an east-west

direction and 3.3 km in a north-south direction.

1.1 Model Objectives

The objectives of this noise assessment are:

• To assess the predicted noise impacts from the proposed BOD upgrade;

• To assess whether any predicted increase in noise levels at selected noise-sensitive

receptors will contribute to an exceedance when compared against the assigned levels

specified by the Environmental Protection (Noise) Regulations 1997; and

• Where required, identify noise mitigation measures to achieve compliance with the

assessment criteria.

1.2 Applicable Documents

The following documents are relevant to this assessment:

• Environmental Protection (Noise) Regulations 1997;

• Pinjarra Refinery Noise Model Design and Verification, Wood Report 1403232-4-100; and

• Draft Guideline on Environmental Noise for Prescribed Premises, Department of

Environment Regulation, May 2016.

1.3 Project Design Documents

The following project design documents and other sources of information were provided by

Alcoa and were used for this study:

1 Wood report: 1403232-4-100-Rev.0-8.Mar.2019

Alcoa of Australia


Rpt01-1404084-Rev0-12Nov19

Page 2

• Oxalate Destruction Building, New Bio Reactor 3, Plan (drawing no, PIN00052 SK-1); and

• Mechanical Equipment List (doc no. PIN00052-RW150302-MP-LST-0001).

Additional to these documents, information supplied for the previous iteration of the model was

also utilised. The results presented in this report are based on the most up-to-date design

information available at the time of writing.

Alcoa of Australia


Rpt01-1404084-Rev0-12Nov19

Page 3

2 SUMMARY OF RELEVANT LEGISLATION

2.1 Environmental Protection (Noise) Regulations 1997

Noise management in Western Australia is implemented through the Environmental Protection

(Noise) Regulations 1997 (the regulations) which operate under the Environmental Protection

Act 1986. The Regulations specify maximum noise levels (assigned levels) which are the

highest noise levels that can be received at noise-sensitive premises, commercial and industrial

premises. Table 2-1 presents the assigned noise levels.

Assigned levels have been set differently for noise sensitive premises, commercial premises,

and industrial premises. For noise sensitive premises, e.g. residences, an “influencing factor” is

incorporated into the assigned levels. The influencing factor depends on land use zonings within

circles of 100 m and 450 m radius from the noise receiver, including:

• The proportion of industrial land use zonings;

• The proportion of commercial zonings; and

• The presence of major or secondary roads.

For noise sensitive residences, the time of day also affects the assigned levels.

The regulations define three types of assigned noise level:

• LAmax assigned level means a noise level which is not to be exceeded at any time;

• LA1 assigned level which is not to be exceeded for more than 1% of the time;

• LA10 assigned level which is not to be exceeded for more than 10% of the time.

The LA10 noise limit is the most significant for this study since this is representative of continuous

noise emissions from the Pinjarra refinery.

Alcoa of Australia


Rpt01-1404084-Rev0-12Nov19

Page 4

Table 2-1 : Assigned Levels

Type of premises receiving noise

Time of Day Assigned Level (dB)

LA10 LA1 LAmax

Noise sensitive premises: highly sensitive area

0700 to 1900 hours Monday to Saturday

45 + Influencing factor



0900 to 1900 hours Sunday and public holidays




1900 to 2200 hours all days




2200 hours on any day to 0700 hours Monday to Saturday and 0900 hours Sunday and public holidays




Noise sensitive premises: any area other than highly sensitive area

All hours 60 75 80

Commercial premises All hours 60 75 80

Industrial premises All hours 65 80 90

2.2 Assigned Levels for Selected Receptors

Five representative receptor locations have been identified, see Figure 2-1 and Table 2-2.

Figure 2-1 : Location of Selected Receptors Surrounding Pinjarra Refinery

Table 2-2 : Co-ordinates of Selected Receptors

Receptor Coordinates

R1 32° 40.948'S, 115° 57.152'E

R2 32° 37.069'S, 115° 58.200'E

R3 32° 36.627'S, 115° 53.898'E

R4 32° 37.522'S, 115° 52.828'E

Alcoa of Australia


Rpt01-1404084-Rev0-12Nov19

Page 5

R5 32° 38.200'S, 115° 52.803'E

A portion of the land within 450 m of Receiver 1 is zoned as Industrial resulting in a 1 dB

influencing factor.

The South Western Highway is classified as a secondary road, while traffic flows on other nearby

roads are insufficient to be classified as either major or secondary roads. Receptor 4 (R4) has

a transport factor of 2 dB because it is less than 100 m away from the South Western Highway.

The influencing factor at receptors 2, 3 and 5 is 0 dB.

Table 2-3 presents the assigned levels, including influencing factors, at the selected receptors.

Table 2-3 : Assigned Levels at Selected Receptors Surrounding Pinjarra Refinery

Time of Day Assigned Level – LA10 dB(A)

R1 R2 R3 R4 R5

0700 to 1900 hours Monday to Saturday

46 45 45 47 45

0900 to 1900 hours Sunday and public holidays

41 40 40 42 40

1900 to 2200 hours all days 41 40 40 42 40

2200 hours on any day to 0700 hours Monday to Saturday and 0900 hours Sunday and public holidays

36 35 35 37 35

2.3 Adjustments for Intrusive Characteristics

Received noise levels associated with refinery operations must be adjusted if the noise exhibits

intrusive or dominant characteristics, i.e. if the noise is impulsive (e.g. banging), tonal (e.g.

whining noise having a defined pitch) or modulating (e.g. noise which varies cyclically in either

pitch or amplitude). Table 2-4 presents the adjustments required when intrusive or dominant

characteristics cannot be reasonably and practicably removed. The adjusted noise levels must

now comply with the assigned noise levels. Regulation 9 sets out objective tests to assess

whether the noise is taken to be free of these characteristics.

Table 2-4 : Adjustments for Intrusive or Dominant Noise Characteristics

Adjustment where noise emission is not music these adjustments are cumulative to a maximum of 15 dB

Where tonality is present Where modulation is present Where impulsiveness is present

+5 dB +5 dB +10 dB

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3 NOISE MODELLING METHODOLOGY

3.1 Existing Noise Model

The previous model developed in March 2019 for the Pinjarra Refinery Noise Model Design and

Verification2 has been used to model the proposed BOD upgrade. This model contains the

refinery base with residue filtration.

The BOD area of the previous model has been altered to bring it in line with the most current

data received from Alcoa, see section 1.3. This preliminary update (which included more

accurate location of noise sources as well as inclusion of some minor noise sources which were

previously excluded) has not affected the predicted noise levels of the Alcoa facility appreciably,

the results for these changes are summarized below in Table 3-1. The previous model with

preliminary update is used as the base model for the proposed BOD upgrade.

The base model contains the refinery base with filtration and with the BOD plant updated to

match the existing facility.

Table 3-1 : Receiver Sound Levels Before and After BOD Base Case Preliminary Update

Receiver Base Pre-Update Base Post-Update Diff.

Facility BOD Facility BOD Facility BOD

R1 35.9 11.6 35.9 11.6 0.0 0.0

R2 40.7 25.2 40.7 26.4 0.0 1.2

R3 33.5 12.5 33.5 12.6 0.0 0.1

R4 33.3 9.8 33.3 9.5 0.0 0.3

R5 34.1 8.8 34.1 8.5 0.0 -0.3

From the base model an updated model has been configured by applying the proposed changes

to the BOD plant. Additional noise sources and reflective surfaces that are part of the proposed

plant upgrade were added to the base noise model, and noise sources for equipment that is

planned to be upgraded have been replaced with updated sound power levels.

The updated model contains the refinery base with filtration and the updated BOD plant with the

proposed upgrades.

For the base and updated models noise contours were prepared and noise level predictions

were undertaken to assess the impact of the proposed upgrade. Each assessment was run

twice: once on the BOD in isolation, and again on the entire facility including the BOD. This was

done to assess the contribution of the BOD to the overall noise levels as well as the resulting

noise levels for both the base and updated state of the model.

At the time of this noise model update, the filtration plant model has not yet been updated using

survey data. The current assessment has been undertaken using assumed sound power data

for the filtration plant based on the most up to date noise emission data, as was used in the


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previous iteration of the model. However, because of the relative contribution of the BOD to

received noise levels, this does not affect the assessment of the noise impact of the BOD.

3.2 Noise Model Program

A noise model has been developed for the Pinjarra Refinery using SoundPlan noise modelling

software, which has been previously accepted by WA Department of Water and Environmental

Regulation (DWER) as appropriate for environmental noise prediction.

The inputs required in SoundPlan are noise source data, barriers/screens, ground topographical

and absorption type data, assessed meteorological conditions and receiver point locations.

The model has been used to generate predicted noise contours for the area surrounding the

refinery and to predict noise levels at the selected noise sensitive receptors.

The model does not include noise emissions from any sources other than those at the Pinjarra

Refinery, its residue operations and the filtration plant. Noise emissions from other neighbouring

industrial sources, road traffic, aircrafts, animals, domestic sources, etc. are excluded from the

modelling.

3.3 Noise Model Algorithm

SoundPlan provides a range of published noise propagation prediction algorithms that can be

selected by the user. The CONCAWE3,4 prediction algorithms were selected for consistency

with previous modelling undertaken for Alcoa.

The CONCAWE algorithms are also recommended by the WA DWER Draft Guideline5.

3.4 Selection of Meteorological Conditions

SoundPlan calculates predicted noise levels for defined meteorological conditions. In particular,

the following variables are included in the prediction algorithms and will affect the predicted

noise level: temperature; Pasquill stability (temperature inversion); relative humidity; wind

speed; and wind direction.

3 CONCAWE (Conservation of Clean Air and Water in Europe) was established in 1963 by a group of oil companies to carry

out research on environmental issues relevant to the oil industry.

4 The propagation of noise from petroleum and petrochemical complexes to neighbouring communities, CONCAWE Report

4/81, 1981

5 Draft Guideline on Environmental Noise for Prescribed Premises, May 2016, DWER2015/001319, Department

of Water and Environment Regulation

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The night-time “default meteorological conditions” as suggested by the WA DWER Draft

Guideline have been used to determine the worst-case overall predicted noise levels at each

selected noise sensitive receiving location. These are presented below in Table 3-2.

Table 3-2 : Noise Model Meteorological Inputs for Worst-Case Conditions

Model Parameters Value

Temperature 15 ºC

Pasquill Stability Class F

Wind Speed 3 m/s

Wind Direction Source to receiver (Worst-Case)

Relative Humidity 50%

3.5 Ground Topography

Ground elevation data (topography) was supplied by Alcoa during the 2012 model build and has

not changed. Topography for the residue area was supplied at 1m contour line spacing, whereas

the topography for the refinery and surrounding lands was supplied at 5m spacing. The

increased resolution of the contours in the residue area is appropriate due to the localised

shielding effects provided by the bunding in this area.

At the residue disposal area, all the dams and bunds for impoundments and water storage

facilities have been incorporated into the ground contours.

3.6 Acoustic Effects for Existing Structures

Structures that have the potential to create reflections and barrier effects (e.g. buildings, tanks)

have been included in the model where their potential influence on modelled noise levels is

considered to be significant.

3.7 Ground Absorption

The following ground absorption factors were used in the model:

• A ground factor of 0.3 has been used for the majority of the flat ground surrounding the

refinery;

• More hilly and dense bushland to the east of the refinery has been modelled with a ground

factor of 0.8;

• Compacted ground in the residue area has been modelled as at 0.2;

• The Refinery area has been modelled with a ground factor of 0.15 to represent the

combination of asphalt, concrete, dirt and foliage;

• Partially filled tails ponds have been modelled as 0.1. The stockyard has been modelled at

0.4; and

• A reflective ground (ground factor 0) has been used for propagation over water.

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3.8 BOD Noise Sources

Details of the project noise sources and assumptions are provided in the following sections of

this report. Appendix A summarises the sound power levels assumed for BOD upgrade noise

sources (new or modified) in the model. Source sound power levels for the other elements of

the existing refinery and residue area operations are presented in Pinjarra Refinery Noise Model

Design and Verification6.

Sound power levels for new and upgraded equipment have been assumed to be in line with

industry standards and are for the most part based on measured sound power levels for similar

equipment at Alcoa’s refineries.

3.8.1 Base Case

The locations of noise sources have been adjusted slightly for the base case model compared

to the preexisting model to better match the layout drawing of the current BOD which was

provided as an input to this study. (BOD Source locations in previous models were estimated

from Google earth images.)

In previous model iterations, some sources in the BOD were omitted from the model due to their

low noise contributions being considered insignificant. As this model revision is specifically

concerned with the BOD, some of the previously omitted low noise sources have been added

to the noise model for the sake of completion: the added sources are listed below:

• Cooling water discharge pump;

• Oxalate storage tank agitator;

• Oxalate repulp pump;

• Oxalate booster pump; and

• Sump pumps (oxalate, BiOx, nutrient, and cooling water areas).

3.8.2 Air Blower

A fourth air blower has been added to the noise model. The air blower is modelled as a single

point source at the same sound power level as the existing air blower units. To represent typical

operating conditions for the BOD, three of the four air blower units are included in the updated

model as operational.

3.8.3 Bioreactor Tank

A third bioreactor tank has been added to the noise model. The bioreactor tank is modelled as

two main noise sources:


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• The bioreactor agitator; and

• The bioreactor underflow pumps.

Both sources copy the sound power levels of the existing agitator and underflow pumps. Only

one of the two new underflow pumps as modelled as operational.

3.8.4 Cooling Water

The existing 45 kW cooling water discharge pump is remodeled as a 75 kW discharge pump,

through an increased sound power level. To represent typical operating conditions for the BOD,

one of the two cooling water discharge pumps has been included in the updated model as

operational.

3.8.5 Oxalate Repulp Tank

The existing 15 kW pumps in the oxalate repulp area are being upgraded to 22 kW pumps. This

change is represented through an increased sound power level.

3.8.6 Scrubber

A fourth scrubber induced draft fan has been added to the noise model. The scrubber fan is

modelled as a single point source at the same sound power level as the existing scrubber units.

To represent typical operating conditions for the BOD, three of the four induced draft scrubber

fan units are included in the updated model as operational.

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4 MODELLING RESULTS

The following contours are available in Appendix B:

• Figure B-1, the existing near-field BOD noise contour, without contributions from outside of

the plant;

• Figure B-2, the proposed near-field BOD upgrade noise contour, without contributions from

outside of the plant;

• Figure B-3, the Pinjarra refinery far-field noise contour including the existing BOD; and

• Figure B-4, the Pinjarra refinery far-field noise contour including the proposed BOD

upgrade.

4.1 Noise Levels

The results for the ‘worst case’ modelled noise levels at the selected noise sensitive receivers

are presented below in Table 4-1. The modelled ‘worst case’ scenario builds upon the

established worst-case scenario previously employed in the Pinjarra Refinery Noise Model

Design and Verification and uses the default meteorological conditions recommended by DWER

for worst-case scenario modelling, see section 3.4.

Table 4-1 : Worst-Case Predicted Noise Levels, Before and After the Proposed BOD Update

Receiver

Night-Time

LA10

Assigned Level

Predicted Results dB(A)

Entire Facility Levels BOD Contribution

Base Model

Updated Model

Diff. Base Model

Updated Model

Diff.

R1 36 35.9 35.9 0.01 11.6 13.1 1.5

R2 35 40.7 40.8 0.05 26.4 27.6 1.2

R3 35 33.5 33.5 0.01 12.6 14 1.4

R4 37 33.3 33.3 0.01 9.5 11.3 1.8

R5 35 34.1 34.1 0.01 8.5 10.5 2.0

The BOD contribution to received noise levels at the most affected receptor (R2) is more than

13 dB below the contribution of the entire refinery.

4.2 Tonality

Given that the noise contributions from the BOD are insignificant when compared to the overall

noise levels generated from the Pinjarra facilities, it is highly unlikely that noise from the BOD

would be able to protrude significantly above the ambient noise levels to an extent that tonality

would be discernible at any of the selected noise sensitive receivers. Even if the predicted model

indicated tonality in the noise emissions generated by the BOD it would not contribute noticeably

to the overall tonality heard at residential receiver locations.

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5 CONCLUSION

The following conclusions can be drawn from this noise impact assessment:

• Noise emissions associated with the BOD upgrade will not contribute measurably to the

existing noise levels at the selected noise sensitive receiver locations;

• Predicted noise from new and modified equipment associated with the BOD upgrade does

not contribute to any exceedance of the assigned levels; and

• Any intrusive or dominant characteristics associated with the BOD upgrade will not protrude

sufficiently above ambient levels to be discernible at noise sensitive receptors surrounding

the refinery.

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APPENDIX A BOD MODELLED NOISE SOURCES

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Source Name Status Northing Easting Elevation Source Type

Source Sound Power Data dB(A)

Comment Total LW

63 Hz

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

Air Blower No.1 Existing 6388381.3 401666.0 51.9 Point 101.9 77 89 89 91 99 95 92 87 Survey result : 19/09/2018

Air Blower No.2 Existing 6388387.6 401665.9 51.8 Point 101.9 77 89 89 91 99 95 92 87 Based off Air Blower No.1

Bioreactor Agitator No.1

Existing 6388387.2 401687.0 59.9 Point 104.8 59 72 91 97 98 91 102 88 Based off bioreactor agitator No.2


Existing 6388387.2 401699.0 59.9 Point 104.8 59 72 91 97 98 91 102 88 Survey result : 27/07/2017

Bioreactor Area Sump Pump

Existing 6388372.0 401677.3 51.0 Point 87.0 51 62 72 77 84 82 77 - Survey result : 2012

Bioreactor Feed Pump No.1


Bioreactor Product Pump No.1


Bioreactor Underflow Pump No.1




Cooling Tower Fan No.1


Cooling Tower Fan No.2

Existing 6388389.5 401748.9 57.1 Point 92.3 65 80 85 86 87 86 75 69 Based off Cooling Tower Fan No.1

Cooling Tower Intake Vent No.1

Existing 6388397.0 401752.5 53.6 Point 96.4 66 85 90 90 93 84 80 71

Survey result : 19/09/2018 Source is directional.

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Comment Total LW

63 Hz

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz

Cooling Tower Intake Vent No.2

Existing 6388389.5 401752.5 53.6 Point 96.4 66 85 90 90 93 84 80 71

Based off Cooling Tower Intake Vent No.1 Source is directional.

Cooling Water Area Sump Pump

Existing 6388402.9 401733.8 51.0 Point 87.0 51 62 72 77 84 82 77 - Based off bioreactor area sump pump

Cooling Water Discharge Pump

Existing 6388393.5 401738.9 51.5 Point 81.0 55 62 70 74 77 73 71 68 Survey result : 2012

Feed Prep Tank Agitator


Nutrient Area Sump Pump


Oxalate Booster Pump


Oxalate Relay Sump Pump


Oxalate Repulp Pump


Oxalate Storage Tank Agitator


Scrubber Induced Draft Fan No.1




Air Blower No.4 New 6388393.9 401665.9 51.8 Point 101.9 77 89 89 91 99 95 92 87 Based off Air Blower No.1

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Comment Total LW

63 Hz

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz


New 6388397.2 401699.0 59.9 Point 104.8 59 72 91 97 98 91 102 88 Based off bioreactor agitator No.2


New 6388394.3 401706.1 51.4 Point 94.8 57 73 78 82 87 92 89 78

Based off bioreactor underflow pump No.1


New 6388374.6 401702.6 51.5 Point 100.8 56 78 87 93 95 95 94 87 Based off scrubber induced draft fan No.2

Cooling Water Discharge Pump

Upgrade 6388393.5 401738.9 51.5 Point 83.3 58 64 72 76 80 75 73 70

Based off Cooling Water Discharge Pump Increased by 10log(Pnew/Pold)

Oxalate Booster Pump

Upgrade 6388340.8 401619.5 48.5 Point 85.7 48 69 74 78 81 79 78 73

Based off Oxalate Booster Pump Increased by 10log(Pnew/Pold)

Oxalate Repulp Pump

Upgrade 6388333.2 401626.8 49.0 Point 86.1 33 71 81 75 78 72 78 80

Based off Oxalate Repulp Pump Increased by 10log(Pnew/Pold)

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APPENDIX B NOISE CONTOURS

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Figure B-1 Worst-Case Predicted Noise Contour, BOD, Pre-Upgrade

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Figure B-2 Worst-Case Predicted Noise Contour, BOD, Post-Upgrade

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Figure B-3 Worst-Case Predicted Noise Contour, Full Site, Pre-Upgrade

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Figure B-4 Worst-Case Predicted Noise Contour, Full Site, Post-Upgrade

Appendix 3

Alcoa Risk Rating and Risk Criteria Tables

Finance/Risk Management/General

AOARMI002 Risk Management - Consequence, Probability & Risk Matrix - Standard Applications (AOA)

Consequence Matrix Rating Health & Safety Environment Regulatory Image & Reputation Financial Impacts Facility Integrity Project Performance Employees

5 Critical Fatality of staff, contractor or

the public Long term environmental

damage (5 years or longer),

or requiring >$5 million to

study or correct

Regulatory intervention and

prosecution possible Damage to corporate reputation at international level; raised in international media. Major loss of shareholder,

political or community

support

Direct loss or increased cost > $20 million Estimating error or capital loss > $20 million Fraud > $1 million

Major unacceptable system, asset, integrity or condition problem Failure to achieve critical system, asset or

performance goals

Time-critical project misses major milestone or deadline > 6 months Failure to achieve critical system, asset or

performance goals

A large number of senior

managers or experienced

employees leave the

company

4 Major Serious injury or

occupational illness

(nonrecoverable) or

permanent major disabilities

(acute or chronic)

Medium-term (1-5 yr)

environmental damage, or

requiring $1 to 5 million to

study or correct

Breach of licenses,

legislation, regulation or

Corporate-mandated

standards

Damage to corporate reputation at national level; raised in national media Significant decrease in

shareholder, political or

community support

Direct loss or increased cost of $5 – 20 million Estimating error or capital

loss of $5 – 20 million Fraud

$0.5 - 1 million

Failure to achieve some system, asset, integrity or condition targets Failure to achieve some

performance targets

Time-critical project misses major milestone or deadline by 3-6 months Failure to achieve some

performance targets

Some senior managers or experienced employees leave High turnover of experienced employees Company not perceived as

an employer of choice

3 Moderate Lost time or restricted

duties injury or occupational

illness (recoverable)

Short-term (<1 yr)

environmental damage, or

requiring up to $1 million to

correct

Breach of standards,

guidelines or impending

legislation, or subject raised

as a corporate concern

through audit findings or

voluntary agreements

Adverse news in state or regional media Decrease in shareholder,

political or community

support

Direct loss or increased cost of $1 – 5 million Estimating error or capital loss of $1 – 5 million Fraud $0.25 - 0.5 million

Some reduction in system, asset, integrity or condition Some reduction in

performance

Time-critical project misses major milestone or deadline by 1-3 months Some reduction in

performance

Poor reputation as an employer Widespread employee attitude problems High employee turnover

2 Minor Medical Treatment or First Aid Injury No lost time or occupational

illness

Environmental damage

requiring up to $250,000 to

study or correct

Breach of internal

procedures or guidelines Adverse news in local media Concerns on performance

raised by shareholders,

political or the community

Direct loss or increased cost of $0.25 – 1 million Estimating error or capital

loss of $0.25 – 1 million Fraud $0.1 - 0.25 million

Minor system, asset, integrity or condition degradation Minor performance

degradation

Time-critical project misses major milestone or deadline by <1 month Minor performance

degradation

General employee morale and attitude problems Increase in employee

turnover

1 Insignificant No Injury Negligible environmental

impact, managed within

operating budgets

No breach of licenses,

standards, guidelines or

related audit findings

Reference to community consultation group Public awareness may exist, but there is no public

concern

Direct loss or increased cost below $250,000 Negligible estimating error or capital loss Negligible fraud

Negligible system, asset, integrity or condition impact Negligible performance

impact

Negligible milestone or deadline delay Negligible performance

impact

Negligible or isolated

employee dissatisfaction


AOARMI002 Risk Management -

Consequence, Probability & Risk Matrix - Standard Applications (AOA)

Probability Matrix

PROBABILITY

The potential for events to occur and lead to the assessed consequences

Descriptor

Alternative styles of rating selection

Rating Judgement Frequency Experience

A

Almost

certain Or

Frequent Almost Certain

to occur.

Very High, may

occur at least

several times per

year

A similar outcome has arisen several times per year in local operations

B

Likely

Or

Probable

More likely

than not to

occur.

High, may occur

about once a year

A similar outcome has arisen

several times per year in Alcoa

operations worldwide or broader

industry

C Possible or

Occasional

As likely to

occur as not to

occur.

Possible, may occur

at least once in a

one to ten year

period

A similar outcome has arisen at

some time previously in local

operations

D

Unlikely

Or

Remote

Less likely not

to occur than

to occur.

Not impossible, likely

to occur during the

next ten to twenty

five years

A similar outcome has arisen at

some time previously in Alcoa

operations worldwide or broader

industry

E

Rare

Or

Improbable

Not very likely

to occur

Very low, very

unlikely during the

next twenty five

years

No experience of this happening

in the broader worldwide industry

but is theoretically possible


AOARMI002 Risk Management -

Consequence, Probability & Risk Matrix - Standard Applications (AOA)

Risk Matrix – Qualitative Likelihood

Consequence Rare Unlikely Possible Likely Almost certain

E D C B A

5

4

3

2

1

Critical

Major

Moderate

Minor

Insignificant

Medium Medium High Very High Very High

Low

Low

Medium High High Very High

Medium Medium High High

Low Low Medium Medium Medium

Low Low Low Low Medium

Risk Matrix –Semi Quantitative Likelihood

Consequence Rare Unlikely Possible Likely Almost certain

E D C B A

5

4

3

2

1

Critical

Major

Moderate

Minor

Insignificant

5 10 15 20 25

4

3

8 12 16 20

6 9 12 15

2 4 6 8 10

1 2 3 4 5

Appendix 4

Dr Peter May. Effect of Oxalate Bioreactor on Mercury Emissions at the Pinjarra Refinery, 2011

Faculty of Science and Engineering

School of Chemical and Mathematical Sciences

Office of the School Dean

90 South Street

Murdoch WA 6150 AUSTRALIA

Ph: +61 8 9360 6068, Fax: +61 8 9310 6452

Email: [email protected]

3 March 2011

Dear Dr Tilbury

Effect of Oxalate Bioreactor on Mercury Emissions at the Pinjarra Refinery

Thank you for referring this question to me.

Based on the information you have provided regarding (a) the oxalate destruction proposal, (b)

the mercury concentration in the liquid phase following causticisation of the bioreactor effluent

using pressed mud, (c) the current Pinjarra mercury balance and (d) my previous experience

modelling mercury deportment around the refinery circuit at Wagerup, I conclude that

commissioning of the oxalate bioreactor will have no measurable effect on the level of

mercury emissions to air. This is because the amount of mercury that would be returned to the

refinery circuit prior to the evaporation stage of the process will be insignificant.

The key parameters underpinning my conclusion above are as follows.

1. Oxalate destruction will be achieved using two bioreactors each operating at 22.5 tpd

involving a mercury flux that is estimated to be 24 kg/year.

2. Your experimental investigation of a pressed-mud causticisation of the bioreactor effluent

indicating that 90% of the mercury will partition to the solids and only 10% will remain in

the liquid phase.

3. The proposed intention that the causticised bioreactor effluent slurry will then be

introduced into the washer circuit (between C11 and C12) with the effect that the solids

report directly to the plant residue.

4. Current mercury emissions to air at Pinjarra have been estimated by AWA in an

appropriately conservative way (428 kg/year).

5. Mercury flows in the circulating liquor at Pinjarra are likely to be of a similar magnitude to

those from AWA’s Wagerup mercury balance and as previously modelled by me [Mercury

Deportment at Wagerup and the Control of Mercury Emissions to Air on Restarting the

Oxalate Kiln, Report to Alcoa World Alumina, August 2009], namely in the order of

thousands of kg/year.

6. It is likely that a significant fraction of any mercury returned to the liquor circuit (from the

liquid phase following pressed-mud causticisation) will eventually report to the plant

residue.

I am therefore confident that there will be no significant change in mercury emissions to air from

the plant at Pinjarra resulting from the installation of the oxalate bioreactors as described.

Professor Peter M May

School Dean and Research Chair in Extractive Metallurgy