Teacher background information
Wastewater in WA
Wastewater is a hidden part of everyday life and is collected daily from households, commercial businesses and industries. The wastewater from properties connected to Water Corporation’s wastewater system, is carried away in sewers and transported to a treatment plant.
In WA, Water Corporation is responsible for the treatment and disposal of wastewater. It operates more than 100 wastewater treatment facilities around the State. The three large metropolitan plants at Beenyup, Subiaco and Woodman Point treat approximately 80% of our wastewater.
How is wastewater treated?
Wastewater treatment is a series of processes that remove the pollutant materials from wastewater such as solids, oil and greases, detergents, nutrients, heavy metals and bacteria. These processes are carried out at wastewater treatment plant. Wastewater treatment involves speeding up the natural processes of bacterial breakdown and removing solids by filtration and settling. The treated wastewater is then either:
- returned to the marine environment via ocean outfalls
- reused in horticulture or to irrigate recreational areas
- allowed to infiltrate back into the ground or evaporated.
Groundwater replenishment in WA
Groundwater replenishment is an innovative concept where treated wastewater is further treated to drinking water standards and recharged into groundwater supplies. The water is then stored and taken out some time later for further treatment and supply to a drinking water system.
The successful completion of a three-year Groundwater Replenishment Trial at the end of 2012 showed conclusively that it is a highly viable option to boost much needed drinking water supplies in WA.
The trial was endorsed by the regulators, Departments of Health, Water and Environmental Regulation (formerly Environment and Conservation). In August 2013, the State Government announced that groundwater replenishment would become the next new climate independent water source for Perth.
Groundwater replenishment scheme
The initial stage of Australia’s first full-scale groundwater replenishment scheme will have the capacity to recharge 7 billion litres of recycled water annually and is planned to begin recharging by 2016. The scheme can ultimately deliver around 28 billion litres of quality drinking water per year, and can be staged to meet our population growth and water supply needs, which is currently due for completion in 2022.
Perth’s Groundwater replenishment scheme is similar to the Californian approach where treated wastewater is further treated to drinking water standards and added to groundwater for later use in drinking supplies. Other water recycling schemes that supplement drinking water supplies also exist in Singapore and in Windhoek, Namibia.