Sydney

13.7.1 Discharge of urban wastewater to connected surface water

Supporting information

The volume of treated water from wastewater treatment plants and water recycling plants discharged to connected surface water during 2009–10 is 54,576 ML (see the following table).

Breakdown of urban wastewater discharge to rivers

Description	Plant	Discharging to watercourse	Volume discharged during 2009–10 (ML)
Sydney Water Corporation—treated wastewater from water recycling plants	Castle Hill	Cattai Creek	2,645
	Glenfield	Georges River	101
	Liverpool	Georges River	1,361
	Penrith	Boundary Creek	8,356
	Picton	Stonequarry Creek	0*
	Quakers Hill	Breakfast Creek	11,369
	Richmond	Rickabys Creek	223
	Rouse Hill	Second Ponds Creek	3,513
	St Marys	South Creek	7,999
	West Camden	Matahil Creek	1,126
Sydney Water Corporation—treated wastewater from wastewater treatment plants	Brooklyn	Hawkesbury River	75
	Fairfield	Orphan School Creek	872
	Hornsby Heights	Calna Creek	2,106
	North Richmond	Redbank Creek	292
	Riverstone	Eastern Creek	600
	Wallacia	Warragamba River	211
	West Hornsby	Waitara Creek	4,520
	Winmalee	Nepean River	6,465
Shoalhaven City Council—treated wastewater from wastewater treatment plant	Berry	Broughton Creek	149
	Bomaderry	Abernathy's Creek	927
	Nowra	Shoalhaven River	1,666
Total			54,576

* During 2009–10, received wastewater was treated to produce recycled water for on-site and agricultural uses.

The volumes shown in the above table (accounted for the line item) reached the sea. They did not become inflows to downstream storage reservoirs.

Treated water released from wastewater treatment plants to streams reaching downstream storage reservoirs (following table) has not been accounted for in this line item. It has been accounted as:

run-off to reservoirs in Line item 13.4.1 Landscape water drain to connected surface water
reflection of decreases in the water distribution system store in Line item 20.4.1 Discharge of urban wastewater to connected surface water.

Quantification approaches for the discharge volumes stated in the following table are available in Line item 20.4.1.

Operator	Wastewater treatment plant	Discharging to watercourse	Reservoir receiving the discharge	Volume discharged during 2009–10 (ML)	Comments
Goulburn Mulwaree Council	Goulburn and Marulan	No	No	0	The plants received 1569 ML. Treated water was used for irrigation
Lithgow City Council	Lithgow	A tributary of the Coxs River	Lake Lyell	1,516	Metered inflows to the plants
Lithgow City Council	Wallerawang	Coxs River	Lake Wallace	218	Metered inflows to the plants
Palerang Council	Braidwood	A tributary of the Shoalhaven River	Lake Yarrunga (Tallowa Dam)	79	Estimated volume from metered inflow to the plant
Wingecarribee Shire Council	Berrima	Olbury Creek	Lake Burragorang (Warragamba Dam)	78	Recorded from outflow meters
	Bowral	Wingecarribee River		1,127
	Braemar	Iron Mines Creek		785
	Bundanoon	Reedy Creek		303
	Moss Vale	Whites Creek	Medway	793
Total				4,899

Quantification approach

This line item comprises two different data-sets. The method for each data-set is shown below.

Note a: Shoalhaven City Council

Data source

Shoalhaven City Council telemetry system.

Daily data registers in respect of the operations of the plants.

Data provider

Shoalhaven City Council.

Method

Outflows from wastewater treatment plants were measured as follows:

Berry wastewater treatment plant: Vega-type ultrasonic flow meter
Bomaderry and Nowra wastewater treatment plants: a Parshall flume with a venturi flow meter at each site.

Uncertainty

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

Approximations, assumptions, caveats/limitations

Nil.

Note b: Sydney Water Corporation

Data source

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

Data provider

Sydney Water Corporation.

Method

Total metered volume of treated wastewater discharge to surface water from Sydney Water Corporation’s wastewater treatment plants and water recycling plants is provided.

The flow of wastewater from 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 a complex data management system. Adjustments are made to the data (if necessary) to correct any interruptions, errors and so on. Data have been extracted for 2009–10 from the data management system.

Uncertainty

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

Approximations, assumptions, caveats/limitations

Nil.

National Water Account 2010