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
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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
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.
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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
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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
Oxalate Bioremoval Facility Engineering layout drawing Oxalate Destruction Building PIN00052 SK-1, see Appendix 1.
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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
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
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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
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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.
Alcoa of Australia Limited 10
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
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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.
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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) – 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
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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.
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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.
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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.
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Table 7: Identification of key emissions and the potential for impacts during construction, commissioning and operation of third bioreactor.
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
Pinjarra town site (west) – approx. 6.6km Fairbridge (north) – approx. 4.5km Private residences located between 2.4km to 6.8km
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
Pinjarra town site (west) – approx. 6.6km Fairbridge (north) – approx. 4.5km Private residences located between 2.4km to 6.8km
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
Pinjarra town site (west) – approx. 6.6km Fairbridge (north) – approx. 4.5km Private residences located between 2.4km to 6.8km
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
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.
Refuelling of equipment and storage of chemicals used for construction activities
Waste and leachate
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
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.
Insignificant Unlikely Low No
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
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
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
Pinjarra town site (west) – approx. 6.6km Fairbridge (north) – approx. 4.5km Private residences located between 2.4km to 6.8km
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.
Insignificant Unlikely Low No
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
Pinjarra town site (west) – approx. 6.6km Fairbridge (north) – approx. 4.5km Private residences located between 2.4km to 6.8km
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.
Normal operation of equipment Trace amounts of mercury contained in oxalate material emitted via vapours from bioreactor tanks
Point source mercury emissions to air
Pinjarra town site (west) – approx. 6.6km Fairbridge (north) – approx. 4.5km Private residences located between 2.4km to 6.8km
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
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 commissioning or operation.
Pump failure, spills, loss of containment, leaking equipment, pipes, tanks
Contaminated or potentially contaminated stormwater
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
Impacts on the beneficial use of groundwater and surface water Adverse health effects to ecosystem Health and amenity impacts
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
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
Impacts on the beneficial use of groundwater and surface water Adverse health effects to ecosystem Health and amenity impacts
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.
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
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