CS00005 Beenyup Wastewater Treatment Plant Energy Recovery

CS00005 Beenyup Wastewater Treatment Plant Energy Recovery Facility Works Approval Supporting Information – October 2018

CS00005 Beenyup WWTP Plant Energy Recovery Facility Works Approval

Document Information Document Title CS00005 – Beenyup Wastewater Treatment Plant Energy Recovery

Facility Document reference 20070798

Version Date Author(s) Reviewer(s) Comment Draft 1 26/09/2018 Craig

Chaudhry

Final 26/09/2018 James Gee 28/09/2018 Brendan Vernall 08/10/2018 Dion Hill 08/10/2018 Brian Scott 11/10/2018 Juliet Cole


3 20070798

Contents 1 Purpose ............................................................................................................................... 6

2 Premise and Applicant Details .......................................................................................... 6

2.1 Occupier Details 6 2.2 Premise Details 6 2.2.1 Prescribed Premise Details 6 2.2.2 Siting 7

3 Existing Environment ....................................................................................................... 12

3.1 Specified Ecosystems 12 3.2 Bush Forever Site 303 12 3.3 Flora, vegetation and Flora 12

4 Proposed Activities .......................................................................................................... 16

4.1 The scope of the proposed activities: 16 4.2 Location of ERF 16 4.3 Proposed Energy Recovery Facility 17 4.4 Operation of ERF 17 4.5 Biogas treatment plant 18 4.5.1 Biogas quantity and quality 18 4.6 Combined Heat and Power units 19 4.7 Associated works and SCADA 20 4.8 Project timing 20 4.8.1 Commissioning 20

5 Regulatory Context and Approvals ................................................................................. 21

5.1 Environmental Protection Act 1986 – Part V 21 5.2 Other Approvals 21

6 Stakeholder Consultation ................................................................................................ 21

7 Risk Assessment .............................................................................................................. 21

7.1 Odour 24 7.1.1 Source Pathway and receptors 24 7.1.2 Proposed Controls 24 7.1.3 Odour Risk Assessment 24 7.2 Noise 25 7.2.1 Source Pathway and receptors 25 7.2.2 Proposed Controls 25 7.2.3 Noise Risk Assessment 26


4 20070798

7.3 Gaseous Emissions 27 7.3.1 Source Pathway and receptors 27 7.3.2 Proposed Controls 27 7.3.3 Gaseous Emissions Risk Assessment 27 7.4 Dust Emissions 28 7.4.1 Source Pathway and receptors 28 7.4.2 Proposed Controls 28 7.4.3 Dust Emission Risk Assessment 29 7.5 Waste Streams 29 7.5.1 Source Pathway and receptors 29 7.5.2 Proposed Controls 30

8 Fee Calculation ................................................................................................................. 31

9 References ........................................................................................................................ 31

Figures Figure 1 Location of the Premise .................................................................................................... 8 Figure 2 Site Location, Specified Ecosystems, and sensitive receptors ........................................ 12

Appendices Appendix A Environment Policy ............................................................................................ 32

Appendix B Certificate of Title ............................................................................................... 34

Appendix C Additional reports and supporting information .............................................. 37

Table of attachments The following table shows how the mandatory attachments referenced in the Department of Water and Environmental Regulation application form have been addressed in this document.

DWER Attachment

Description Location in this document

Comment

1A Proof of occupier status Appendix B Refer also to Section 2.2 1B ASIC company extract N/A Water Corporation does not

have an ASIC extract 1C Authorisation to act as a representative of

the occupier NA NA

2 Premises map/s Figures 1a-b, Figures 2a, 2d


5 20070798

3A Proposed activities Section 4

3B Map of area proposed to be cleared (only applicable if clearing is proposed)

Not Applicable no clearing

3C Additional information for clearing assessment

Not Applicable no clearing

4 Biodiversity surveys (only applicable if biodiversity surveys included in application)

No surveys undertaken no clearing

5 Other approvals and consultation documentation

Sections 5 Section 6

6A Emissions and discharges Section 7 6B Waste acceptance NA

7 Siting and location Figures 1a-b, Figures 2a, 2d

8 Additional information submitted Appendix C 9 Proposed fee calculation Section 9

10 Request for exemption from publication NA


6 20070798

1 Purpose This document has been prepared to support an application for a Works Approval for construction and subsequent operation of the proposed Beenyup Energy Recovery Facility (ERF).

2 Premise and Applicant Details

2.1 Occupier Details The Water Corporation is a statutory entity and was established by Section 4(1) of the Water Corporations Act 1995 (WC Act). The Corporation is a body corporate (Section 4 of the WC Act) and as such does not have an ASIC company extract.

The Water Corporation provides water, wastewater and drainage services to Perth and hundreds of towns and communities spread over 2.5 million square kilometres of Western Australia. Water Corporation holds many licences for Wastewater Treatment Plants (WWTPs) with the Department of Water and Environmental Regulation (DWER).

The Water Corporation operates to an environmental management system certified to ISO 14001, which enables the systematic identification of environmental risks, setting of targets and development of environment improvement plans to reduce risks and ensure its activities are sustainable. The environmental management system is guided by the Corporation’s Environment Policy (Appendix A).

2.2 Premise Details

2.2.1 Prescribed Premise Details The premise currently undertakes sewage treatment and discharge to land or waters and has a design capacity of 135 ML/day cubic meters per day. This means the category fits the definition of Category 54 and 61 (Table 1).

Table 1 Prescribed Premise Category Category Description Threshold 54 Sewage facility premises –

(a) On which sewage is treated (excluding septic tanks); or

(b) From which treated sewage is discharged onto land or into waters

Category production or design capacity of 100 cubic meters or more per day. Category approved premise production or design capacity 135,000 cubic meters per day

61 Liquid waste facility: premises on which liquid waste produced on other premises (other than sewage waste) is stored, reprocessed, treated or irrigated.

Category production or design capacity 100 tonnes or more per year. Category approved premises production or design capacity 50,000 tonnes per annual period.


7 20070798

2.2.2 Siting The Beenyup Wastewater Treatment Plant (BWWTP) is located on Lot 8278 on Plan 30778, Ocean Reef Road, Craigie. The closest residents at Craigie are 310m from the active part of the BWWTP. The main emissions from the plant are noise, odour and treated wastewater to surface waters (ocean).

A map of the premises is included in Figure 1 and the GPS coordinates for the current premise boundary are provided in Table 2a. A copy of the Certificate of title is provided in Appendix B.

Table 2a (Current) Prescribed Premise Boundary Coordinates


8 20070798

Table 2b Beenyup ERF Coordinates

Point Easting Northing

1 384433.562m 6482400.142m

2 384389.586m 6482397.447m

3 384389.611m 6482486.798m

4 384427.067m 6482484.558m


9 20070798

Figure 1a: Premise Map for Beenyup WW


10 20070798

Figure 1b: Beenyup ERF Coordinates


11 20070798

Figure 1c Beenyup ERF Location Map


12 20070798

3 Existing Environment

3.1 Specified Ecosystems The DWER Guidance Statement: Environmental Siting (DER, 2016) lists specified ecosystems that must be considered when assessing the risk of prescribed premises. Analysis against the datasets listed in Appendix 1 of the guidance statement indicates the following specified ecosystems occur adjacent to the premise:

• Bush Forever Site 303 (ESA) • Threatened Fauna.

The nearest sensitive receptors consist of:

• Residents located approximately 560 meters west of the proposed Beenyup ERF. • Residents located approximately 287 meters east of the proposed Beenyup ERF. • Commercial premises 320m North of the proposed Beenyup ERF.

3.2 Bush Forever Site 303

The premise is located adjacent to Bush Forever Site 303 (see Figures 2a, 2b, 2c and 2d).. This area consists of remnant bush islands that extend along the eastern boundary of the site. The surrounding bushland varies in quality from Good to Highly Degraded.

The Water Corporation undertakes management activities within the Bush Forever site including weed control, fire management and rehabilitation.

3.3 Flora, vegetation and Flora Several flora, vegetation and fauna surveys have been conducted for the general Beenyup project area (including the Bush Forever Site) to inform the Advance Water Recycling Plant (AWRP) project (Bennett Environmental Consulting 2005; Ecologia 2012; GHD 2013). No Declared Rare or Priority Flora has been recorded in the surveyed area.

In 2005, Western Wildlife (Wilcox and Davies 2005) undertook a Level 1 fauna survey of the Beenyup project area. The report concluded that Bush Forever Site 303 is likely to support a diverse range of vertebrate fauna, including some species of conservation significance and emphasised the importance of preserving Tuart trees.

No clearing will be undertaken for the construction of the Beenyup ERF or associated noise mitigation wall.


13 20070798

Figure 2a Site Location and Specified Ecosystems


14 20070798

Figure 2c Sensitive receptors


15 20070798

Figure 2d: Prescribed Premise Map


16 20070798

4 Proposed Activities This application is to allow for the construction and operation of an Energy Recovery Facility (ERF) within the Beenyup WWTP.

Investigations have demonstrated that there is sufficient quantity of biogas available from the current digestion process to establish an ERF. The ERF would use the biogas to produce both electrical power to meet a significant portion of the AWRP’s internal power requirements, and hot water to heat the WWTP’s digestion process.

4.1 The scope of the proposed activities: The activities associated with this application are:

• Construction of a biogas treatment plant incorporating a desulphurisation unit, dehumidifier and activated carbon filter to substantially reduce H2S and siloxanes (silica based compounds) and relative humidity levels to meet typical engine specifications

• Installation/construction of an additional blower to convey gas through the biogas treatment process and additional compressors to provide appropriate gas pressure to the engines

• Installation/construction of two (2) off-packaged reciprocating engine generator Combined Heat and Power (CHP) units, housed in bunded, acoustic weather protective enclosures

• Associated electrical and other works • Provision of SCADA remote control and monitoring at both the WWTP and the Water

Corporation Operations Centre • Commissioning of the works • Construction of an acoustic barrier.

4.2 Location of ERF The proposed $19 million ERF will be of a compact layout located at the south east corner of the BWWTP. It is proposed to comprise a gas treatment plant located in the area to the south of the biogas holder and two combined heat and power (CHP) gas engines adjacent to the existing hot water heaters (Figure 3 in Appendix C). The available area has been cut in below natural ground level and is bounded by a cut batter to the east and south, some 4m in height. It was originally thought that the batter to the south will need to be cut into by a few metres resulting in the removal of a very small area of highly degraded Marri woodland. Subsequent detailed design has confirmed that this is no longer required.

The existing internal road that runs around the perimeter of the site will be terminated at the biogas heaters. A turning area will be constructed to enable light vehicle access to the area for maintenance and monitoring purposes.

To the west and east of the BWWTP are the residential suburbs of Craigie and Woodvale respectively, with the Kwinana Freeway separating Woodvale from the BWWTP site. The closest residents at Woodvale are approximately 300m from the active part of the BWWTP. To the south of the proposed ERF and within the BWWTP’s site boundary is natural bushland comprising Bush Forever Site 303. The portion of the Water Corporation’s land occupied by the BWWTP is securely fenced.


17 20070798

4.3 Proposed Energy Recovery Facility Previous investigations have demonstrated that there is sufficient quantity of biogas available from the current digestion process to establish an ERF. The ERF would use the biogas to produce both electrical power to meet a significant portion of the AWRP’s internal power requirements, and hot water to heat the WWTP digestion process.

AWRP power demand is estimated to be around 4,000 kilowatts (kW) with maximum calculated demand of peaks of more than 6,000 kW. It is not possible to export power to the grid, so the power generated by the ERF must be dynamically capped to be less that the instantaneous plant power demand. Biogas generated during the digestion process contains contaminants that must be removed before combustion to minimise operation and maintenance requirements. This is not required for the existing heaters, but is vital to protect the components of the ERF from corrosion due to high hydrogen sulphide (H2S) concentrations, moisture and other corrosive contaminants in the biogas. Note: future operation of the existing heater would benefit from treated biogas which will be the case when heaters are called out of standby (i.e. during CH maintenance activities).

The Water Corporation has undertaken detailed engineering investigations and design to ensure the proposed ERF and biogas treatment are robust and will enable long term efficient generation of power with minimal maintenance.

The Water Corporation is aware that there are similar facilities installed and operating at numerous wastewater treatment plants in Australia, including Bolivar, Christie’s Beach and Glenelg WWTPs (South Australia); Bondi, Glenfield, Liverpool, Warriewood, Malabar and Wollongong WWTPs (New South Wales); Gippsland and Werribee WWTPs (Victoria); Luggage Point and Oxley Creek WWTPs (Queensland).

4.4 Operation of ERF The ERF will operate in the following manner:

• Biogas produced by the digesters will continue to flow into and be stored in the biogas holder.

• Biogas will be drawn from the biogas holder to feed into the gas engines and to maintain a supply to the existing gas heaters (i.e. to keep them operating on standby), after being treated in the biogas treatment plant to remove contaminants and excessive moisture.

• If the biogas treatment plant fails for any reason to produce treated biogas within the engines’ operating specifications (including if spikes of H2S of 6,000ppm or more are detected at the inflow to the engines), the engines and biogas treatment plant will shut down automatically and the biogas will be diverted to the waste gas burners.

• The two gas engines will generally operate in parallel, but at times may operate singly (for example during maintenance of an engine, when low levels of electricity are required to power the AWRP, when one engine fails for whatever reason).

• Where both gas engines are not in use, the gas heaters will ramp up to continue to maintain mesophilic temperature conditions in the digesters.

• Where the gas engines are not in use, the excess biogas not required by the gas heaters will continue to be stored in the gas holder.

• When the capacity of the gas holder is close to its maximum of 2400m3, biogas will automatically be released to the waste gas burners and flared.


18 20070798

4.5 Biogas treatment plant

4.5.1 Biogas quantity and quality The total volume of biogas currently produced by the digesters is around 1,000 Nm3/hour, ranging from a minimum of around 400 Nm3/hour and up to 1,500 Nm3/hour. The gas engines will be sized to each combust a throughput of 590 Nm3/hour (i.e. a total of 1180 Nm3/hour). This larger volume of biogas will be produced as flows to the BWWTP increase over the next 15 years.

The Water Corporation has been undertaking biogas quality analysis from the BWWTP digesters for a number of years. The main components of biogas of interest are methane, H2S, moisture, and siloxanes.

Methane varies between 53% mol and 66% mol and average design methane content is taken to be 59.5% mol.

Significant H2S levels have been found. The average H2S level is around 2,000 ppmv, but occasionally spikes of 6,000 to 10,000 ppmv are experienced. As spikes above 6,000ppmv are rare, this level has been taken as the maximum design H2S content, above which the engines will automatically shut down and the biogas will divert to flare.

For design purposes the moisture content is assumed to be at the saturation limit for the process temperature, as it is likely that to date the analysis undertaken probably does not reflect the actual levels in the biogas due to sampling losses. The ambient conditions for Perth can be subject to a wide range of diurnal and seasonal temperatures (i.e. ranging from 0 - 45 degrees Celsius). This can affect the process biogas temperature at the proposed tie-in point, and therefore the saturated moisture content in the biogas.

Siloxane ranges and average levels were found to range from absent up to a simple arithmetic total of 18.8mg/Nm3, with average levels of up to 2.1mg/Nm3 for octa-siloxanes.

The biogas feed therefore is required to be treated to reduce H2S, siloxanes and relative humidity levels so that the biogas supplied to the engines will meet typical engine manufacturer specifications and minimise corrosion.

4.5.2 Biogas Treatment Concept The Water Corporation investigated two main scrubbing systems for removing sufficient levels of H2S: a system based either on chemical (caustic) scrubbing or biological scrubbing. Due to stringent biogas quality requirements of the CHP, the system adopted for this project is the THIOPAQ desulphurisation. This system uses a primary caustic scrubbing circuit which is guaranteed to reduce H2S concentrations to 100ppm. To reduce site caustic consumption, this technology uses a continual biological caustic regeneration within a secondary regeneration circuit. The process flow is shown on Figure 3 below.

Following H2S removal, the scrubbed biogas will be sent through a chiller to dehumidify the gas, and the condensate will be sent to the plant’s internal wastewater collection system and returned to the inlet works. Finally the gas will be passed through an Activated Carbon scrubber to remove any remaining siloxanes not removed in the upstream process.

The “sulphur slurry” waste product produced by the desulphurisation unit will be sent to the sludge dewatering system and combined with sludge prior to injection into the centrifuges. It’ll then be


19 20070798

carted offsite along with the dewatered solids. The spent Activated Carbon will be removed and disposed of to a licenced landfill.

A third “Front End” booster biogas blower will be provided (additional standby capacity for the existing two units) to ensure sufficient pressures are maintained to keep biogas flowing through the biogas treatment system, and to achieve a positive suction pressure to the proposed “Back End” biogas booster compressors which maintain the required inlet temperatures to the CHP. The preferred location of the blowers within the biogas treatment system have been determined by the system vendor.

The benefits of the adopted gas treatment approach are:

• The biological regeneration circuit of the desulphurisation unit stage offsets the large caustic consumption required by chemical only unit.

• The approach is robust, has been proven to be capable of dealing with high peaks in H2S loading and for higher biogas flows and allows optimum operation to be maintained in the biological scrubber.

• Boasts high H2S Removal Efficiency - Deep H2S removal with the expected average treated biogas H2S value will be below 100 ppm at any inlet H2S concentration.

• High tolerance to variable sulphur loads and biogas flows. Robust system against H2S variations. It can handle the expected H2S load variations from 2,000 ppm up to 6,000 ppm with the same guarantees.

• The system will not require upgrading to accommodate significant additional sulphur load. • Only the waste activated carbon will need to be disposed of offsite.

Although not yet completed, the detailed engineering design stage has provided details of the exact assets to be constructed and operated to ensure the feed biogas stream to the CHP units consistently meets requirements.

4.6 Combined Heat and Power units Two reciprocating engine CHP units will be installed to generate electrical power to offset a significant portion of the power requirements for AWRP. The CHP units will also recover waste heat, via a heat exchanger, to heat water for biological enhancement in the digesters and so mitigate the requirement for the use of biogas in the existing hot water units.

Each individual CHP unit is to be approximately 1.5 MWe, with the engines set to generate the maximum amount of electricity for the available biogas and to minimise the volume of biogas flared. The engines and gas treatment systems will operate continuously.

The space for the engines and their ancillary equipment on site is rather limited so they will be located in individual enclosures (extra-wide 40ft shipping containers) rather than in a dedicated building. The enclosures will provide acoustic cladding and weather protection, and are sufficiently large to enable the majority of the maintenance work to be performed within the enclosure. The enclosures will be bunded to trap any hydrocarbons which may spill or leak from the gas engines.

Modelling undertaken by the Water Corporation has been used to determine increase in biogas production over time, to help in sizing the engines to be installed. On this basis, the Water Corporation has adopted a 15-year life for the CHP Units, after which time, with the growth in production in biogas, larger engines will replace the existing ageing engines.


20 20070798

When replacement is required, the entire container will be craned onto a flatbed truck and taken offsite to have the engines replaced within the enclosure; and trucked back and reinstated. There is sufficient space available to provide a third engine package adjacent to the proposed two engine packages, for flexibility and as a contingency.

4.7 Associated works and SCADA The scope of works includes:

• Works on the digester heating circuits to integrate the plant to the site and meet Western Power requirements.

• Minor changes to the existing digester heating circuits to attenuate plant thermal demand. • Reconfiguration of gas pipework to ensure existing gas flares will operate if gas engines are

offline and biogas production is more than required by gas heaters. • Augmenting the plant control system to include new programmable logic controller at the

ERF. This will cover the gas treatment, overarching engine control, hot water recirculation and heating system.

4.8 Project timing The construction works will be undertaken from estimated October 2018 to March 2019 (approximately six (6) months to complete). Commissioning will take up to six months following the completion of construction.

The activities covered by this application include:

• Construction of the ERF. • Commissioning of the ERF. • Operation of the of the ERF.

4.8.1 Commissioning Commissioning of the ERF will take up to six (6) months. The (environmental) Commissioning Plan for this project details the commissioning process for this project which will include:

1. Testing to ensure all pipework and vessels within the project works are free from leaks. 2. Verification of required flows, pressures and temperatures throughout the plant. 3. Seeding of the reactor to bring them on line. 4. Testing each component of the biogas treatment system to ensure biogas supplied to the

engines will meet typical engine manufacturer specifications. 5. Testing to ensure all electrical and instrumentation circuitry is fully functional. 6. Testing to ensure correct operation of BMS control functions , the remote PLC program and

SCADA operator interfaces. 7. Carrying out performance testing under all load conditions. 8. Monitoring the operation of the biogas treatment plant and the CHP units for 30 continuous

days of proof running under normal operating conditions to prove reliability.


21 20070798

5 Regulatory Context and Approvals

5.1 Environmental Protection Act 1986 – Part V

The addition of the Beenyup ERF will be constructed and operated within the prescribed premise boundary of Beenyup WWTP. A licence currently exists (L7882/1992/14) for the operation of Beenyup WWTP.

5.2 Other Approvals

No other approvals required.

6 Stakeholder Consultation The BWWTP has a Community Reference Group that meets regularly and this group has been briefed on the project.

The Water Corporation website has a dedicated BWWTP page and this is updated with the latest information about works at the BWWTP including the ERF project.

7 Risk Assessment A risk assessment has been prepared to consider the risks of the construction and ongoing operation of Beenyup ERF. The risk assessment has been based on the DER Guidance Statement: Risk Assessments (DER, 2017).

Table 3 shows the potential emissions/discharge sources, receptors and pathways that have been identified for the construction, commissioning and operation of the Beenyup ERF. The table also identifies which of these have been identified to undergo a detailed risk assessment. The detailed risk assessment includes:

• A description of the emission source, pathways and receptor. • Any controls that have been identified for the risk event. • An assessment of the consequence and likelihood. • Risk rating.


22 20070798

Table 3 Identification of environmental risks Source Activity Potential

Emission Potential receptor Pathway Impact Inclusion in

Risk Assessment & Justification

Construction Construction of the Beenyup WWTP Energy Recovery Facility

Civil earthworks cutting back the southern embankment

Fugitive dust emission Nearest sensitive residents Air / wind dispersal

Amenity Public Health

Yes

Civil earthworks vehicle

movements and infrastructure construction

Noise emissions Nearest sensitive residents Air / wind dispersal


Yes

Commissioning Beenyup WWTP ERF Biogas Treatment Plant

Biogas treatment system Testing

Odour – Un-combusted Biogas Gas = Methane gas

Surrounding residents Air – Wind dispersal


Yes (Already pre-existing risk)

Noise Emissions Surrounding residents Air / wind dispersal


Yes

Biogas treatment waste

streams Sulphur slurry Land – (will be transferred via

contained pipework’s to the sludge dewatering facility within the WWTP).

Discharge to land

Contamination of land, groundwater

Yes

Condensate water Land (will be transferred via contained pipework’s to the head of the WWTP).

Discharge to land


Yes

Spent activated carbon Land (will be disposed offsite to a licenced landfill)

Land Contamination of land, groundwater

Yes

Operation Beenyup WWTP ERF Biogas Treatment Plant

Operation of the Beenyup ERF

Generation of greenhouse gases

Atmosphere Air dispersal Impact to Air Quality Yes

Emissions of particulates or pollutants

Nearest sensitive residents Air / wind dispersal

Impacts to air quality, amenity or health

Yes

Noise generated by operating equipment

Nearest sensitive residents Air dispersal Amenity Yes

Emission of Odour from biogas combustion or un-combustion

Nearest sensitive residents Air dispersal Amenity Yes


23 20070798

Source Activity Potential Emission

Potential receptor Pathway Impact Inclusion in Risk Assessment & Justification

Emission of waste leachates from seed tank or pipe work

Land Discharge to land


Yes

Biogas post

combustion waste streams

Sulphur slurry

Land – (will be transferred via contained pipework’s to the sludge dewatering facility).

Discharge to land


Yes

Condensate water Land (will be transferred via contained pipework’s to the head of the WWTP).

Discharge to land


Yes

Reclaimed effluent Land (will be transferred via contained pipework’s to the inlet works).

Discharge to land


Yes


24 20070798

7.1 Odour

7.1.1 Source Pathway and receptors Unburnt biogas or exhaust from biogas engines could mobilize odours to residential receptors through air dispersal and wind migration.

7.1.1.1 During Construction No odour emissions are expected during the construction phase.

7.1.1.2 During Operation The operation of the biogas engines and waste gas burners could result in generation of low nuisance odour to residents located 310m away via air/ wind dispersal if process failure occurs or during maintenance activities.

7.1.2 Proposed Controls

7.1.2.1 During Construction

Not applicable - no odour emissions are expected during the construction phase.

7.1.2.2 During Operation Since the installation in 2013 and operation of the second high efficiency waste gas burner replacing the inefficient candle stick type burner, there have been significantly fewer odour events associated with flaring the biogas. As stated the operation of the ERF means that only approximately 1% of the biogas will be flared. This will further substantially reduce the possibility of odour events associated with flaring the biogas. There is not expected to be any unacceptable odour associated with the exhaust from the gas engines. This is because the biogas feed into the engines will be thoroughly treated to remove contaminants to protect the engines from corrosion. The biological and chemical scrubbers and activated carbon filter will essentially remove odorous H2S and traces of other non-methane volatile organic compounds in the biogas prior to combustion. The biogas fed into the engines will be mostly methane, which will be combusted to form NOx, water, carbon dioxide which are odourless. Odours associated with the operation of the Beenyup ERF will be managed by the implementation of the current Beenyup WWTP Odour Management Plan. Additionally interlocks would prevent untreated biogas from being flared.

7.1.3 Odour Risk Assessment

7.1.3.1 Criteria • Public Health and Amenity (DWER ,Risk Criteria Table 1, February 2017). • EPA Guidance Statement 3 Separation Distances between Industrial and Sensitive

Land Uses. • Section 49 EP Act (Unreasonable emissions).

7.1.3.2 Consequence Effects on the health and amenity (low-level nuisance odours) on surrounding residents (locally) 310m away during. Mid-level impact to amenity (historically there have been few odour complaints in relation to Beenyup WWTP. As stated above the operation of the ERF


25 20070798

means that only approximately 1% of the biogas will be flared. This will further substantially reduce the possibility of odour events associated with flaring the biogas and the ability for migration off site).

7.1.3.3 Likelihood Odour emission could occur if the biogas flare fails and the biogas migrates to the nearest resident via air dispersal / wind migration. The ERF reduces the amount of biogas flared significantly – (to 1%).

7.1.3.4 Odour Residual Risk Rating Event Likelihood Consequence Residual Risk

Rating Operation Odour emission impacting amenity during maintenance

Possible – The risk event could occur at some time

Moderate – Mid level impact to amenity

Low

Odour emission could occur if biogas flare fails

Rare – The risk may only occur in exceptional circumstances

Moderate – level impact to amenity

Low

7.2 Noise

7.2.1 Source Pathway and receptors Noise emissions from vehicles, construction, and operation of the ERF through air dispersal and wind migration.

7.2.1.1 During Construction During the construction phase noise will be created from associated construction activities and vehicle movements.

7.2.1.2 During Operation During operation, noise emission (with no controls) will occur from the ERF.


7.2.2.1 During Construction During the construction phase, noise levels will be similar to those associated with normal construction projects involving use of building construction plant, equipment and power tools. Construction activities and hence noise will be limited to standard working hours (7am to 7pm, Monday to Saturday). Noise impacts during construction will be managed through the Contractor’s Work Instructions and the development of a Construction Environmental Management Plan.

During construction, work will be limited to between 07:00 and 19:00h Monday to Saturday and the contractor is required to ensure works are conducted in accordance with Section 4 of AS2436-2010. The contractor must document the manner in which this will be achieved in a Construction Environment Management Plan prior to works commencing.

Environmental Objective Performance Indicator Ensure that activities do not unreasonably affect the amenity of surrounding landowners

• No substantiated noise related complaints


26 20070798

7.2.2.2 During Operation

The ERF engines will also generate noise emissions. Specifications to engine vendors will require noise emissions to be no greater than 85dB(A) at any point 1.5m above ground level, and 1m away from the acoustic enclosure respectively. The noise emissions to sensitive receptors (being the residents) are LA10 requiring no more than 45dB during the day and 35dB at night (as per the Environmental Protection (Noise) Regulations of 1997 (as amended).

The proposed location for the ERF is the south eastern corner of the BWWTP, and is 310m west of the nearest residences of Woodvale on the eastern side of the Mitchell Freeway. The nearest residents live approximately 50m from the freeway and hence the influencing factor is 7-8. That is the assigned noise levels increase by 6 to 96, 86, and 71 dB(A) respectively.

Noise modelling undertaken in 2015 (Herring Storer Acoustics, 2015 in Appendix C attachment A) demonstrated that the construction of a 25m long noise barrier would eliminate all potential noise impacts to the east of the site. Such a noise barrier is to be constructed of solid 0.48BMT (min.) sheet metal and located atop the eastern embankment extending to a height of RL25 (Refer to Appendix C Attachment A).

The ERF engine packages will be both acoustically enclosed and located adjacent to the above described noise barrier so that the Environmental Protection (Noise) Regulations of 1997 are met and residents will not experience adverse noise levels associated with operation of the engines.

7.2.3 Noise Risk Assessment

7.2.3.1 Criteria • Public Health and Amenity (:DWER ,Risk Criteria Table 1, February 2017). • EPA Guidance Statement 3: Separation Distances between industrial and Sensitive

Land Uses. • EPA Guidance Statement 18: Prevention of air quality impacts from land

development sites.

7.2.3.2 Consequence Low level nuisance effects on the health and amenity (low noise) on surrounding residents (locally) 310m away during which corresponds with a consequence of moderate.

7.2.3.3 Likelihood During construction with controls in place, it is expected that potential low level noise emission are unlikely to occur.

During operation with controls in place, it is expected that noise emission will not occur at unreasonable levels with the installation of the noise barrier and acoustically enclosed engines.

7.2.3.4 Noise Residual Risk Rating Event Likelihood Consequence Residual Risk

Rating Construction Construction of the Beenyup ERF Noise Emission

Unlikely - The risk event could occur at some time

Minor – low level impact to amenity

Moderate

Operation Operation of the Rare – The risk event Minor – low level Low


27 20070798

Beenyup ERF Noise Emission

will probably not occur in most circumstances

impact to amenity

7.3 Gaseous Emissions

7.3.1 Source Pathway and receptors Emission of greenhouse gases to the local air shed from the combustion of biogas from the Beenyup ERF.

7.3.1.1 During Construction Not applicable as the Beenyup ERF will not be operated during construction.

7.3.1.2 During Operation Emission of greenhouse gases will occur from the combustion of biogas from the operation of the Beenyup ERF.


7.3.2.1 During Construction Not applicable as the Beenyup ERF will not be operated during construction.


The engines will generate NOx which will be released to atmosphere. Specifications to engine vendors will require NOx emissions to be less than 500mg/Nm3 at 5% O2. In the absence of an Australian Standard, 500mg/Nm3 was adopted as being an appropriate performance criterion, as it is the standard generally used in similar Western European applications and it is achievable by the engine manufacturers.

It should be noted that the main source of NOx in Australia is from vehicle emissions (approximately 80%), with the remainder from industrial combustion (fossil fuel burning power stations) and other sources.

The emissions from the proposed engines represent an insignificant contribution to overall atmospheric NOx levels. In addition, similar levels of NOx are currently produced and released to atmosphere, because the biogas is flared.

As the biogas will be ‘productively’ utilised to generate power and heat to be used onsite, there will be very little excess biogas produced over requirements. The Water Corporation has calculated that currently approximately 82% of biogas generated from the sludge digesters is currently flared. However with the ERF in operation, approximately only 1% the biogas will be flared. While this does not change the emissions of NOx to atmosphere, it will result in a large reduction in SOx currently being emitted to atmosphere from flaring the biogas.

7.3.3 Gaseous Emissions Risk Assessment

7.3.3.1 Criteria • Environment and Public Health and Amenity (DWER, Risk Criteria Table 1, February

2017). • EPA Guidance Statement 12 Minimising Greenhouse Gases.


28 20070798

7.3.3.2 Consequence Greenhouse Gases will be emitted from the Beenyup ERF. There, however, are so insignificant to affect the local air shed and are considered not to have any impacts to the environment.

Emission of GHG will occur from the combustion of the biogas the risk event of emission is given.

7.3.3.3 Gaseous Emissions Residual Risk Rating Event Likelihood Consequence Residual Risk

Rating Construction N/A NA – No emission NA – No emission NA – No

emission Operation Operation of the ERF GHG Emission to Air Shed – Environment

Almost Certain Slight – Specific consequence Criteria (for environment likely to be met).

Low

7.4 Dust Emissions

7.4.1 Source Pathway and receptors Dust emission to surrounding residents 310m away and locally at site.

7.4.1.1 During Construction Dust generation temporarily anticipated during construction mostly during cutting back the southern embankment.

7.4.1.2 During Operation Not applicable no dust generation during the operation of the Beenyup ERF.


7.4.2.1 During Construction

There is approximately 310m between the ERF site and the nearest residents, which will ensure minimal impacts of dust generated on the ERF site.

Dust suppression during construction, as required, and to be included in project Construction Environmental Management Plan (CEMP)

The contractor for the works will be contractually bound to take all reasonable and practicable measures to meeting the objective below.

Environmental Objective Performance Indicator Activities do not unreasonably affect the amenity of surrounding landowners and users.

• No visible dust plumes extending more than 10m off the development envelope boundary

• No substantiated complaints relating to dust impacts.


29 20070798

7.4.2.2 During Operation Not Applicable - no dust emissions during the operation of the Beenyup ERF.

7.4.3 Dust Emission Risk Assessment

7.4.3.1 Criteria • Public Health and Amenity (:DWER ,Risk Criteria Table 1, February 2017). • EPA Guidance Statement 3: Separation Distances between Industrial and Sensitive

Land Uses. • EPA Guidance Statement 18: Prevention of air quality impacts from land

development sites.

7.4.3.2 Consequence Dust plumes could affect the Public Health and Amenity if not managed on site. The likely hood is rare once controls are in place and the consequence slight.

.

7.4.3.3 Likelihood Dust emission off site is rare with dust plumes unlikely to leave site as construction controls will be in place such as watering of stockpiles and tracks and earth moving management (as described in DWER’s Guideline for managing the impacts of dust and associated contaminated from land development sites, contaminated site remediation other related activities March 2011).

7.4.3.4 Dust Emissions Residual Risk Rating Event Likelihood Consequence Residual Risk

Rating Construction Dust Emission to Nearest Residents

Rare – The risk event will probably not occur in most circumstances

Slight – Specific consequence Criteria (for public) health met

Low

7.5 Waste Streams

7.5.1 Source Pathway and receptors .

During operation the Beenyup ERF treatment process produces the following waste streams as described under 7.5.1.1:


The biogas treatment plant will generate three waste streams – a sulphur slurry (elemental sulphur) which will be mixed with treated sludge for dewatering; incidental reclaimed effluent/water blowdown to be sent back to the head of the plant; and spent activated carbon that will be disposed of to a licenced landfill. The combined flow rates of the slurry waste


30 20070798

streams represent less than 0.04% of the sludge dewatered and is considered insignificant in terms of impact on the wastewater treatment processes.


7.5.2.1 During Operation • Spent carbon will be sent to landfill. • Sulphur slurry with treated sludge sent to the sludge dewatering facilities via

contained pipe. • Routine inspection of lines. • QA/QC for inspection of to be installed pipes.

7.5.2.2 Consequence If the emission of the sulphur with treated wastewater was emitted outside of the process to land it would be contained with the operational presence with no contact to the public (being the premise is fenced). The consequence environmentally would be considered minor and the Public health impact considered no existent as the impact would be localised and could be contained, recovered and or treated.

7.5.2.2.1 Likelihood The likelihood of this occurring are considered Rare.

7.5.2.3 Waste Stream Residual Risk Rating Event Likelihood Consequence Risk Rating Operation Failure of Waste Stream Pipeline

Rare – The risk event will probably not occur in most circumstances

Minor – Onsite impact minimal no public health impacts

Low


31 20070798

8 Fee Calculation Estimated Fee Calculation $20,503.00

9 References Herring Storer Acoustics (January 2015) Water Corporation Energy Recovery Facility Environmental Noise Assessments – Beenyup

Department of Environment and Conservation (March 2011) A guideline for managing the impacts of dust and associated contaminates from land development sites, contaminated sites remediation and other related activities.

Western Australian Government (1997) Environmental Protection (Noise) Regulations

Environmental Protection Authority (2015) Separation Distances between industrial and sensitive land Uses - Guidance Statement 3

Environmental Protection Authority (2015) Minimising Greenhouse Gases- Guidance Statement 12

Environmental Protection Authority (2015) Prevention of Air Quality Impacts from Land development sites- Guidance Statement 18

Department of Environment Regulation (2017) Guidance Statement - Risk Assessments

Department of Environment Regulation (2016) Guidance Statement – Siting

Government of Western Australia – Noise Protection Regulations

Environmental Protection (Noise) Regulations of 1997 (as amended)


32 20070798

Appendix A Environment Policy


33 20070798

Double Click to Open

I

http://aqua/link/?doc=5908380


34 20070798

Appendix B Certificate of Title


35 20070798



36 20070798



37 20070798

Appendix C . Additional reports and supporting information


38 20070798

Figure 3 Overall ERF Process


39 20070798

Figure 4 Location of Beenyup WWTP (12410-085-092-01)


40 20070798

Figure 5 Beenyup WWTP Gas Storage and treatment area, and location of burners and CHP Units (12410-070-002-01 and 003-01)


41 20070798


42 20070798

Figure 6: Bio Gas treatment process flow diagram (12410- 035-120-01)


43 20070798

Figure 7: Heat Circuit Process Flow Diagram (12410-035-121-01)


44 20070798

Attachment a: Noise Modelling



45 20070798

Documents

CS00005 Beenyup Wastewater Treatment Plant Energy Recovery