Perth
11.4 Wastewater collected

The volume reported in the water accounting statements (136,392 ML) represents the total volume of wastewater collected from users and transferred to wastewater treatment plants throughout the Perth region during the 2012–13 year.

Total wastewater inflow volumes into each treatment plant during the 2012–13 year are given in the following table.

The wastewater system is one of three subcomponents of Perth's urban water system. The three subcomponents are the:

• urban water supply system
• wastewater system
• recycled water system.

In the Perth region, wastewater is collected from users by the Water Corporation (11.4 Wastewater collected) and transferred to wastewater treatment plants throughout the region.

During the 2012–13 year, approximately 8% of treated wastewater was recycled; 88% discharged to the sea (19.7 Wastewater discharge outside of region); and the rest discharged to rivers (part of 19.5 Discharge from urban water system to surface water) or infiltration lagoons (19.8 Other wastewater discharge). 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. Volumes in the figure annotated with an asterisk (*) indicate flows between urban subcomponents and are not reported in the account. As such, these flows do not have an associated line item number or note.

Schematic diagram of water inflows and outflows during the 2012–13 year for Perth's wastewater system; line item numbers are provided in brackets

Total inflow into each wastewater treatment plant within the Perth region is based on measured inflow data collected by flow meters installed at the site.

This value is estimated to be in the range of +/– 5–10%.