Sydney
19.7 Wastewater discharge outside of region

Supporting Information

The total metered volume of treated wastewater discharged to the sea at wastewater treatment plants and water recycling plants managed by Shoalhaven City Council and Sydney Water Corporation during the 2011 Account is 428,215 ML (see the following table).

Total wastewater discharged out of region
Managing authority Plant type Plant Discharge volume to sea (ML)
Shoalhaven City Council Wastewater treatment  Shoalhaven Heads* 213
Sydney Water Corporation Wastewater treatment  Bellambi 504
Port Kembla 790
Warriewood 6,815
Shellharbour 7,031
Cronulla 20,643
Bondi 46,165
North Head 143,815
Malabar 185,499
Water recycling plant Gerroa 310
Bombo 1,814
Wollongong 14,616
Total 428,215

*Discharge occurs via sand dunes to the sea

Quantification Approach

Quantification Approach

Data Source

Data managed and maintained in an internal data management system by Sydney Water Corporation's (SWC) Operations Division (Systems Assurance).

Provided by

SWC.

Method

The number represents the total volume of treated wastewater discharged to the sea, based on flow meter readings from wastewater treatment plants and water recycling plants managed by SWC.

The flow of wastewater from the plants was measured using flow meters. These measured data are continually monitored and recorded using the Integrated Instrumentation Control Automation and Telemetry System (IICATS). The data are stored within an internal data management system. Adjustments are made to the data (if necessary) to correct any interruptions, errors and so on. Data have been extracted for the 2010–11 year from the data management system.

Assumptions, Limitations, Caveats and Approximations

Nil.

Uncertainty Information

The volume is based on measured data. Estimated uncertainty based on meter accuracy is +/– 2%.

Shoalhaven City Council

Data Source

NSW Water Supply and Sewerage: 'Performance Monitoring' Report 2010–11. (Access through the 'Performance monitoring' webpage of the NSW Office of Water. The report will be included on the webpage from June 2012.)

Provided by

Shoalhaven City Council.

Method

Outflow volumes from Shoalhaven Heads Wastewater Treatment Plant were measured using an Elster meter and a Parshall flume with a venturi flow meter.

Assumptions, Limitations, Caveats and Approximations

Treated wastewater was discharged to the sea via sand dunes, which act as natural sand-bed filters.

Uncertainty Information

The volume is based on measured data. Estimated uncertainty based on meter accuracy is +/– 5%.

Comparative year

The following table compares the value at 30 June 2010 reported in this account with the corresponding value reported in the 2010 Account.

 

Comparative information from the 2010 Account for line item 19.7

2011 Account line item

2010 Account line item

Value reported in the 2010 Account (ML)

Value reported in the 2011 Account (ML)

Additional information

19.7 Wastewater discharge outside of region

20.4.2 Wastewater discharge out of region

395,186

395,186

Change in line item name