Wastewater is treated at 13 treatment plants to enable stringent environmental and health protection standards to be met. Current treatment capacity can serve a population of 130,000 (equivalent persons).
The wastewater collection and transport systems for these schemes include in excess of 1,200 kilometres of pipelines and 228 pumping stations. Shoalhaven Water owns and operates 13 wastewater treatment plants:
First commissioned in 2007, the Bendalong treatment plant treats sewerage for up to 4,600 equivalent persons.
First commissioned in 1978 this treatment plant was updated in 2006 and treats sewerage for up to 3,000 equivalent persons. During dry weather most of the plant’s flow is utilised by a local dairy farm for pasture irrigation.
First commissioned in 1972 the Bomaderry treatment plant is currently undergoing a major upgrade which will link the treated effluent to the Northern Shoalhaven Reclaimed Water Management Scheme (REMS). Integration into the REMS will ensure that up to 90% of the output from the Bomaderry plant will be beneficially reused. The plant treats effluent for up to 12,500 equivalent persons.
First commissioned in 1999 this plant was purpose built to supply our farmers with reclaimed effluent. The plant treats effluent for up to 6,000 equivalent persons.
Use of recycled water has increased from 300 million litres a year in 2001 to approximately 1,600 million litres a year in 2006/2007. This will grow to around 2,500 million litres a year. Information of our Reclaimed Water Management Scheme can be found within the Major Projects section of this website.
First commissioned in1982 this plant was updated in 2002. The treated effluent is piped to Callala’s REMS storage facility. The plant treats effluent for up to 11,000 equivalent persons.
Huskisson / Vincentia
First commissioned in 1973 this plant had an upgrade in 2002. The treated effluent is piped via a 15km transfer main to the Callala REMS storage facility before being reused on local farmland. A sporting field and a local park are irrigated with the reclaimed water from the transfer main. The plant treats up to 14,000 equivalent persons.
First commissioned in 2013 this plant has a large storage facility and irrigation system to service local dairy farming land with highly treated reclaimed water. The system was designed to use a diversion system which directs excess reclaimed water to the Kangaroo Valley River during high rainfall periods. The plant’s treatment capacity is for 1,400 equivalent persons.
First commissioned in 2007 this facility was designed to release reclaimed water to the environment via a dune exfiltration system at Conjola Beach. Other reuse options are being investigated in order to minimise reclaimed water releases in dry periods. The treatment capacity of the plant is for 2,700 equivalent persons.
Milton / Ulladulla
First commissioned in 1975 this facility was first upgraded in 2005, then again in 2008 with a reticulated wastewater collection system completed for Lake Tabourie Village. Reclaimed water is released via an extend ocean outfall 300m off Racecourse Beach, Ulladulla. Reclaimed water irrigation occurs at a local sporting ground. The treatment capacity is for 32,000 equivalent persons.
First commissioned in 1937 this was the Shoalhaven’s first treatment plant. The current treatment process includes discharge of the reclaimed water to the Shoalhaven River via flood mitigation drains. With an upgrade underway this treatment plant will soon link directly to the REMS scheme ensuring that up to 90% of the output will be beneficially used. The treatment capacity of this plant is equivalent to 21,000 persons.
First commissioned in1983 this plant was upgraded in 2012 and now has two new diffused aeration tanks with clear liquids going to filtration and solids going to sludge lagoon for dewatering and use on suitable agricultural properties. There is also a 5ML lined storage pond for treated effluent reuse to the local golf course. The treatment capacity is equivalent to 8,000 persons.
St Georges Basin
First commissioned in 1991, the reclaimed water from this plant is pumped to the Vincentia treatment plant it is given tertiary treatment and then directed into REMS. There is a treatment capacity equivalent to 16,000 persons.
First commissioned in 1990 this plant reuses reclaimed water via an irrigation system at a local sporting ground. The plant has a treatment capacity of 8,000 equivalent persons.
Wastewater Treatment Process
The treatment of domestic wastewater involves the removal of solids, oils and pathogens from the influent or raw wastewater. This is achieved through a variety of physical, biological and chemical processes.
Primary treatment involves the removal of grit and non-biodegradable material.
Secondary treatment involves biological processing to break down and settle solids and organic matter. This is normally achieved using an aeration/settling cycle. Chemicals may be added to assist solids removal. Solids (or biosolids) are removed for further treatment.
Tertiary treatment is designed to polish and further disinfect treated wastewater. Increasingly, sand/media (or Membrane) filtration is being used to remove any solids left over after secondary treatment. Newer treatment plants achieve a high rate of disinfection using either chlorine or ultraviolet light.
Modern wastewater treatment processes produce reclaimed water of a high standard and purity. Final wastewater quality is typically:
- Biochemical oxygen demand <10 parts per million (95%-100% removal)
- Suspended solids <20 parts per million (95%-100% removal)
- Oil & grease <1 part per million (98%-100% removal)
- pH 6.5 – 8.5
- Total nitrogen <15 parts per million (95%-99% removal)
- Total phosphorus <10 parts per million (95%-99% removal)
- Bacteria <1,000 per 100mL (90%-100% removal)
Bio-solids (wastewater sludge) are the organic solids separated from wastewater through treatment processing. Typically they contain significant levels of nutrients such as phosphorus and nitrogen and have been used for many decades as a fertiliser product. Typically wastewater solids are stabilised in lagoons and drying beds for up to 12 months and then de-watered. The bio-solids are then tested to determine where they can be applied in accordance with the NSW Government Guidelines ‘Use and Disposal of Bio-solids Products’.