Perth
11.4 Wastewater collected

The wastewater system is one of three sub-components of Perth's urban water system. The three sub-components 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) and transferred to wastewater treatment plants throughout the region.

During the 2011–12 year, 8% of treated wastewater was recycled; 88% discharged to the sea (19.7); and the rest discharged to rivers (part of 19.5) or infiltration lagoons (19.8). 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. Note that volumes annotated with a * indicate flows between urban sub-components 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 2011–12 year for Perth's wastewater system. Line item numbers are provided in brackets.

The volume reported in the water accounting statements (135,354 ML) represents the total volume of wastewater collected from users and transferred to wastewater treatment plants throughout the Perth region during the 2011–12 year.

Total wastewater inflow volumes into each treatment plant during the 2011–12 year are given in the following table.

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%.