11.4 Wastewater collected
a. Wastewater collected
This volume reported (90,921 ML) represents wastewater inflow into the Adelaide region's wastewater treatment plants (WWTPs). This volume included increases from wastewater discharge to sewer by consumers and any groundwater or stormwater ingress into the system.
|Wastewater treatment plant||
Metered inflow (ML)
|Bolivar High Salinity||
b. Wastewater system overview
The wastewater system is one of three sub-components of Adelaide's urban water system. The three sub-components are the:
- urban water supply system
- wastewater system
- recycled water system.
In the Adelaide region, wastewater is collected (line item 11.4) from users and treated by SA Water at one of their wastewater treatment plants.
During the 2011–12 year the majority (70%: line item 19.7) of treated wastewater was discharged to sea; approximately 25% was recycled (see recycled water system overview) and the remaining portion was discharged to surface water (2%: line item 19.5) or lost during wastewater treatment processes (3%: part of line item 19.20).
The following figure shows all the inflows and outflows associated with the wastewater system. For more detail on a particular flow associated with the wastewater system, refer to the line item notes. A small misbalance is shown and can be attributed to metering inaccuracies and unaccounted losses.
Note that volumes annotated with a * indicate flows between sub-components and are not reported in the account. As such, these flows do not have an associated line item number.
Schematic diagram of water inflows and outflows for Adelaide's wastewater system during the 2011–12 year; line item numbers are provided in brackets
The metered inflow to each WWTP within the Adelaide region was supplied from WWTP records held by SA Water. Most metered flows were manually read and recorded by plant operators. Inflows for each WWTP were aggregated.
Assumptions, limitations, caveats and approximations
This does not include wastewater collected for individual community wastewater management systems.
This includes wastewater collected from outside of the Adelaide region and delivered to the Bird-in-Hand WWTP. Data on the breakdown between wastewater collected within and outside the region were not available. However, the volume from outside the region is assumed to be negligible.
This volume is metered. The uncertainty is estimated to be +/– 10%.