The NSW government and local councils have taken several types of actions to stop the pollution of waterways and they fall into three broad groups:
- stormwater management
- wet weather overflow prevention
- sewage treatment and discharge.
Past and ongoing actions and strategies have improved the water quality at beaches and other NSW waterways, while further intervention will be needed to ensure a continued improvement.
In 1997 the State government introduced programs to manage stormwater, spending $82 million until its completion on 30 June 2006. The quality of stormwater was improved by:
- creating systems to harvest stormwater
- making grants to councils to improve local stormwater systems
- the creation of 100 artificial wetlands to reduce the amount of sediment washed into waterways
- a successful education program that resulted in 1 in 5 people making efforts to reduce stormwater pollution.
The NSW government continued the management of stormwater across the whole urban water cycle.
As a part of the management, catchment management authorities and the then Department of Environment and Climate Change supported local councils with a focus on projects that had importance to the region.
Funding came from the Urban Sustainability Fund, which was funded by local councils’ stormwater management service charge supplemented by grants.
Sydney Water also began a program of stormwater management, investing $19.4 million in:
- 25 quality improvement devices
- one wetland
- a stabilisation project
- education and monitoring.
As a result, 2973 tonnes of sediment and 1903 cubic metres of litter was stopped from entering waterways over a year.
Wet weather overflow prevention
The Northside Storage Tunnel was built to catch wet weather overflow from key sites to the north of Sydney Harbour. The tunnel transports sewage diluted by stormwater to North Head Sewage Treatment Plant before it is discharged via its deep ocean outfall. This stopped 20 billion litres of sewage overflow from flowing into Sydney Harbour.
The Hunter Water Corporation introduced a 20-year strategy in their region to stop wet weather sewage overflows by completing upgrades, additions and repairs, and building a wet weather pumping station to move sewage from the transport system to the Burwood Beach treatment plant during heavy rain.
Sewage/wastewater treatment and discharge
Wastewater treatment plants are vital to improving water quality. These plants collect and treat wastewater (a mixture of sewage and grey water), before releasing it to the environment.
There are now five coastal wastewater treatment plants in the Sydney region, four in the Illawarra region and three in the Hunter region. The largest of the coastal plants are located at North Head, Bondi and Malabar, which treat approximately 75 per cent of Sydney's sewage. Sydney and Hunter water corporations also made additions to and upgrades of treatment plants:
- Between 1984 and 1991 the Sydney Water Corporation built deep ocean outfalls for sewage treatment plants at North Head, Bondi and Malabar. Tests of water at these outfalls showed that the effluent was diluted 200 to 1000 times.
- An extended ocean outfall was built in the Hunter region in the late 1990s.
- The capacity of the Cronulla treatment plant was increased in 2001. Treated wastewater can be used by local industry reducing the amount of discharge into the ocean.
- Bundeena and Maianbar were connected to the Cronulla treatment plant, replacing the septic system.
- In 2002 the transfer of Gerringong and Gerroa to the sewage system from septic tanks was completed. Of the effluent coming from these areas, 90% is reused on agricultural properties in the area.
- In the Illawarra, Sydney Water built:
- a tertiary sewage treatment plant
- a water recycling plant to produce 20 million litres of water each day
- pipelines to transfer sewage to treatment plants and recycled water to BlueScope Steel
- storm flow plants
- a one kilometre outfall to replace the near-shore outfall
- additions to treatment plants to deal with the growing population.
In May 2000, the Environment Protection Authority expanded licensing to cover the whole sewage system not just plants. Licensing regulates what can be discharged and ensures continuous improvement of sewage systems.
Sydney Water also introduced the SewerFix Program to maintain and improve the sewer system to reduce overflows. This is done by:
- clearing blockages
- undertaking maintenance and repairs to prevent issues where there are recurring problems
- introducing telemetry systems into all sewage pumping stations to provide failure warnings and reduce response time. This decreases the likelihood and severity of overflows
- constructing the Northside Storage Tunnel
- removing silt, lining sewers and making additions
- adding to the number of sewer pipes in growing areas.