Reticulated wastewater systems
Reticulated wastewater systems collect and transfer wastewater from houses and business into a wastewater treatment plant (WWTP) owned by a water industry entity. Depending on the level of treatment applied, and the demand for recycled water in the area, the treated effluent from the WWTP is either recycled or disposed into the environment.
The process involves the following stages:
- collection of wastewater
- treatment of wastewater
- the treated water is either then recycled or disposed of.
Collection
Wastewater collection networks or sewerage systems use pipelines and pump stations to transfer wastewater from households and business to a wastewater treatment plant (WWTP).
Alternatively, wastewater can be initially treated via a residential septic tank before being discharged, as primary treated wastewater, into the sewerage system. These collection systems are called a Septic Tank Effluent Disposal System or STEDS.
The Office of the Technical Regulator regulates plumbing and network infrastructure.
Treatment
Wastewater treatment plants use a series of treatment barriers to remove solids, pathogens, organics, and nutrients from sewage to produce effluent that is fit for its intended purpose.
In South Australia, there are over 200 approved wastewater treatment plants in operation that service communities across the state.
Typical treatment technologies include:
- primary treatment via sedimentation or septic tanks
- secondary treatment via an activated sludge process or lagoon system
- tertiary treatment using filtration and chemical treatments
- disinfection via ultraviolet irradiation or chlorination.
The Department for Health and Wellbeing (DHW) adopt the risk management approach defined in the Australian Guidelines for Water Recycling (PDF 2162KB) (AGWR) to assess and approve wastewater treatment processes.
Approval is required by DHW to install wastewater treatment plants (CWMS only) or for any Water Industry Entity (WIE) to dispose or reuse effluent from a wastewater treatment plant.
Recycled
Following treatment effluent can be supplied for reuse. See the following pages for more information:
- Recycled water — general information including uses and benefits
- Recycled water management — process for seeking the relevant approvals
Disposal
When effluent cannot be beneficially recycled, disposal is necessary. Disposal can include discharging treated effluent to the environment via subsurface trenches or evaporation lagoons, and by direct transfer into surface water catchments.
Approval is required from the EPA to discharge treated effluent into a watercourse.
Refer to the On-site Wastewater Systems Code (PDF 2901KB) or the SA CWMS Design Criteria (PDF 840KB) for the design requirements of disposal systems.
Managing recycled water for industry
Refer to recycled water management and the approval process page for information on how to apply for approvals.