Water resource recovery facilities

Wastewater doesn't have to go to waste

Our water resource recovery facilities treat wastewater in a variety of ways before it's recycled, reused, or discharged to rivers or the ocean. 

How wastewater is treated

What we do at each facility

Wastewater treatment levels in detail

How wastewater is treated

Our water resource recovery facilities treat the wastewater that leaves homes or businesses to prevent possible hazards. We use different processes to remove impurities, and treat wastewater to the level that suits the environment (creek, river or ocean) where it will be discharged or how it will be reused. Our treatment levels are primary, secondary, tertiary and advanced tertiary.

Plus, all our facilities recycle water, reuse by-products or generate some of the energy they need to do their job. There are lots of other ways we recover, recycle and reuse wastewater.

The initial treatment level needed depends on:

  • the facility's location
  • where the treated water will be discharged or reused
  • the nature of the facility's catchment area, including wastewater quality.

We follow strict licence conditions issued by the NSW Environment Protection Authority (EPA). The EPA monitors the effect of discharges on water quality and aquatic life.

Find where our wastewater systems are located on our wastewater systems map.

What we do at each facility

ML = megalitres, or million litres

Facility Treatment level Discharge (ML/day) EPL Discharge vol. limit (ML/day)# Discharge location

Bellambi*

Primary
(includes, actiflow treatment and disinfection)

 

Refer to Wollongong
  • Bellambi Point during wet weather.

Bombo

Secondary
(includes disinfection)

4.3

45
  • Ocean outfall Bombo Point.
  • Supplies to Minnamurra Golf Club.

Bondi

Primary

115.6

680
  • Deepwater ocean outfall 2.2 km from shoreline, 63 m maximum water depth, 512 m diffuser zone.

Brooklyn

Tertiary
(includes disinfection)

0.3

2.14
  • Hawkesbury River at 14 m depth on the second pylon of the old road bridge adjacent to Kangaroo Point.

Castle Hill

Tertiary
(includes disinfection)

6.1

80
  • Cattai Creek.
  • Supplies to Castle Hill Country Club.

Cronulla

Tertiary
(includes disinfection)

54.6

432
  • Ocean outfall at Potter Point, Kurnell.

Fairfield*

Primary
(includes chemically assisted sedimentation)

 

Refer to Malabar
  • Occasional discharge via Orphan School Creek to Georges River during wet weather.

Gerroa

Tertiary
(includes screening, storm tank or primary sedimentation, ponding and chlorination)

1.26

85
  • Reused for on-site agricultural irrigation.
  • Excess discharged to sand dune systems.
  • When sand dunes reach capacity, discharged to Crooked River.

Glenfield^

Secondary
(includes ponding and chlorination)

0

Refer to Malabar
  • Treated wastewater transported to Malabar.
  • Occasional discharge to Georges River in wet weather

Hornsby Heights

Tertiary
(includes disinfection)

7

85
  • Calna Creek to Berowra Creek.

Liverpool^

Secondary
(includes ponding and chlorination)

0

Refer to Malabar
  • Treated wastewater transported to Malabar.
  • Reused at Liverpool Golf Course and Warwick Farm Race Course.
  • Supplies to Fairfield Water Resource Recovery Facility (operated by Aquanet and Veolia Water) under Rosehill Recycled Water Scheme.
  • Occasional treated wastewater discharge to Georges River in wet weather.

Malabar

Primary

524

1,199
  • Deepwater ocean outfall 3.6 km from shoreline, 82 m maximum water depth, 720 m diffuser zone.

North Head

Primary

354.9

1,400
  • Deepwater ocean outfall 3.7 km from shoreline, 65 m maximum water depth, 762 m diffuser zone.

North Richmond

Tertiary
(includes disinfection)

1.2

11.2
  • Redbank Creek to Hawkesbury River.

Penrith

Tertiary
(includes disinfection)

26.2

238

Picton

Tertiary
(includes disinfection)

2.5

15
  • Reused on-site for agricultural irrigation.
  • Wet-weather overflows discharged to Stone Quarry Creek.

Port Kembla*

Primary
(includes disinfection)

 

Refer to Wollongong
  • Red Point during wet weather.

Quakers Hill

Tertiary
(includes disinfection)

43

281.2
  • Reused locally.
  • Some excess discharged via Breakfast Creek to Eastern Creek.

Richmond

Tertiary
(includes disinfection)

2

20.1
  • Reused for irrigation at University of Western Sydney (Hawkesbury Campus) and Richmond Golf Course.
  • Excess overflows to Rickabys Creek.

Riverstone

Tertiary
(includes disinfection)

13.9

104
  • Eastern Creek to South Creek.

Rouse Hill

Tertiary
(includes disinfection for waterway discharge, also ultraviolet irradiation and super-chlorination for reuse water)

21.5

151
  • Recycled back to households via local recycling scheme for non-drinking use.
  • Excess discharged to Second Ponds Creek via wetlands to Cattai Creek.

Shellharbour

Secondary
(includes disinfection)

18.6

170
  • Offshore outfall 130 m from Barrack Point, with diffuser zone.

St Marys

Tertiary
(includes disinfection)

22.6

250

St Marys Advanced Water Treatment Plant

Advanced tertiary
(ultrafiltration and reverse osmosis using membrane technology)

50

55
  • Receives flow from St Marys and Penrith to produce highly treated water.
  • Discharged to Boundary Creek under Western Sydney Replacement Flows Recycled Water Scheme.

Wallacia

Tertiary
(includes disinfection)

1

15
  • Warragamba River to Hawkesbury-Nepean River.

Warriewood

Secondary
(includes disinfection)

18.6

125
  • Ocean outfall Turimetta Head.

West Camden

Tertiary
(includes disinfection)

22.9

120
  • Reused at Agricultural Institute.
  • Remainder discharged via Matahill Creek to Hawkesbury-Nepean River.

West Hornsby

Tertiary
(includes disinfection)

12.9

154.3
  • Waitara Creek to Berowra Creek.

Wilton (Bingara Gorge)

Tertiary
(includes disinfection)

 

3
  • Recycled back to households via local recycling scheme for non-drinking use.
  • Reused at Bingara Gorge Golf Club.
  • Occasional discharge to Stringybark Creek.

Winmalee

Tertiary
(includes disinfection)

20.1

330
  • Unnamed creek to Hawkesbury-Nepean River.

Wollongong

Tertiary
(includes disinfection)

39.3

320
  • Reused at BlueScope Steel.
  • Remainder discharged via offshore outfall with diffuser zone.
  • Deep water Ocean Outfall approximately 1 km off Coniston Beach, with Emergency Ocean Outfall off Coniston Beach.

Less than 1% of Sydney's wastewater is discharged to the ocean untreated, at Vaucluse, Diamond Bay and Diamond Bay South. The Refresh Vaucluse Diamond Bay project will ensure that all wastewater is treated at Bondi Water Resource Recovery Facility in the future.

# Discharge volume limit is specified in environment protection licence issued by NSW Environment Protection Authority (EPA).
* Bellambi, Port Kembla and Fairfield water resource recovery facilities only receive flow during storm events.
** Port Kembla and Bellambi water resource recovery facilities are part of the Wollongong system.
^ Fairfield, Glenfield and Liverpool water resource recovery facilities are part of the Malabar system.

Wastewater treatment levels in detail

Primary

Our primary treatment process includes screens, sedimentation and grit removal. Methods include:

  • filtering wastewater through fine screens to remove items such as paper, cotton tips and plastic
  • removing sand and grit that has fallen to the bottom of aerated grit tanks
  • removing solids that have settled to the bottom of sedimentation tanks
  • removing oil and grease that floats to the top of tanks using scrapers.

Secondary

Our secondary treatment process removes carbonaceous organic matter and nutrients (nitrogen and phosphorus) from wastewater. This involves converting soluble decomposable organic matter into biomass. Then the clarification process separates the biomass and any other suspended material from the liquid stream.

We design our treatment process on the characteristics of the wastewater and the nutrients we need to remove. We create conditions for the growth of selective organisms (mainly bacteria) to help with the treatment process. In some cases, our treatment process can even reduce pathogens and heavy metals.
 

This system generally has some or all of 5 key stages:

  1. Fermentation tank
    Solids from the sedimentation tanks are broken down to produce a better carbon supply for microorganisms in the anoxic and aerobic zones. This makes it easier to remove phosphorus.
  2. Anaerobic zone
    Wastewater from the primary treatment process flows into the anaerobic zones. Microorganisms consume carbon into their cells and release phosphates.
  3. Anoxic zone
    No oxygen is available for microorganisms. They use carbon in the organic matter as a food source, converting nitrates to nitrogen gas which is released to the atmosphere.
  4. Aeration zone
    Air works with microorganisms to further break down the wastewater. A number of processes can occur in this zone, like organic carbon removal, nitrogen and phosphorus removal. This depends on the concentration and activity of the biomass, water temperature and dissolved oxygen levels.
  5. Secondary clarifiers
    Remaining solids are settled in a tank. The settled solids can be returned to the anaerobic zone and the clear wastewater may be sent on for tertiary treatment.

IDALs are an alternative secondary process. Settled wastewater is pumped from the primary distribution structure to the IDAL anaerobic zone. Iron-rich spent pickle liquor is added to help remove phosphorus. In IDALs, wastewater goes through 3 stages in one tank: aeration, settling and decanting.

  1. Aeration
    Air is pumped into the IDAL through diffusers. It works with microorganisms in the tank to break down into nitrates and water (nitrification) and organic matter, reducing biological oxygen demand (BOD).
  2. Settling
    Air is no longer pumped into the tank and the water is still. With no oxygen supply, microorganisms use carbon in the organic matter as a food source, converting nitrates to nitrogen gas. The gas is released into the atmosphere. The solid particles settle to the bottom. Some go to a thickening tank before being treated for biosolids production. The rest of the solids are returned to the IDAL to provide microorganisms for incoming wastewater.
  3. Decanting
    After settling, the clear wastewater flows over weirs from the top of the lagoon into an equalising basin. This basin controls the flow to the tertiary treatment process.

Wastewater contains nutrient-rich solids. We treat these solids so they can be reused as biosolids to improve soil for agriculture and gardens.

There are 4 key steps in the treatment process:

  1. Solids are collected from the primary and secondary treatment tanks.
  2. Settled solids may go into digestion tanks for further breakdown of organic matter.
  3. Solids go through a range of different processes to remove water, for example, using centrifuges. The matter left behind is known as biosolids.
  4. Biosolids are ready for reuse in agriculture, forestry, land rehabilitation and landscaping.

Tertiary

Our tertiary treatment process includes clarification and/or filtering and disinfecting, and preparing wastewater for recycling.
 

Treated wastewater from a biological reactor is further treated with coagulants to help remove additional phosphorus particles and group remaining solids together for easy removal in the filters. The treated wastewater then flows to sand filters. It sinks down through these filters where the sand traps particles.

Filtered water then flows to a chlorine contact tank for disinfection. After the water is disinfected, we remove any remaining chlorine before discharging the treated wastewater. Alternatively, we may use ultraviolet lamps for disinfection.

Treated wastewater from biological reactors can be passed through deep sand filters, where the sand traps any remaining particles. Clear wastewater then goes to a water resource recovery facility where it's filtered through fine membranes to remove very small particles.

The water is pumped at high pressure through reverse osmosis membranes. This is the finest level of filtration. It removes molecules including bacteria, viruses and parasites.

The recycled water may also be treated with chlorine before it enters the recycled water distribution pipes.

Advanced tertiary

The St Marys Advanced Water Treatment Plant receives tertiary treated wastewater from St Marys Water Resource Recovery Facility and Penrith Water Resource Recovery Facility. It provides advanced tertiary treatment using membrane technology and produces up to 50 ML of highly treated recycled water each day.