Sydney
9.9 Discharge from urban water system

The volume of treated water from wastewater treatment plants and water recycling plants discharged to surface water during the 2010–11 year is 64,591 ML made up of flows that reached the sea (58,402 ML), and flows that reached downstream storages (6,189). Details of discharge volumes are provided in the following tables.

Sydney Water Corporation released 15,989 ML of recycled water from St Marys Water Recycling Plant to Boundary Creek (a tributary of the Nepean River). In the future, such releases are intended to replace outflows released for environmental purposes from Lake Burragorang (Warragamba Dam) to the river. The date for these releases is yet to be determined.

Breakdown of urban wastewater discharge to rivers

Description	Plant	Discharging to watercourse	Volume discharged during 2010–11 (ML)
Sydney Water Corporation – treated wastewater from water recycling plants	Castle Hill	Cattai Creek	2,991
	Glenfield	Georges River	156
	Liverpool	Georges River	1,434
	Penrith	Boundary Creek	1,526
	Picton	Stonequarry Creek	220
	Quakers Hill	Breakfast Creek	6,946
	Richmond	Rickabys Creek	501
	Rouse Hill	Second Ponds Creek	3,887
	St Marys	South Creek	3,662
	St Marys	Boundary Creek	15,989
	West Camden	Matahil Creek	1,805
Sydney Water Corporation – treated wastewater from wastewater treatment plants	Brooklyn	Hawkesbury River	94
	Fairfield	Orphan School Creek	740
	Hornsby Heights	Calna Creek	2,250
	North Richmond	Redbank Creek	317
	Riverstone	Eastern Creek	561
	Wallacia	Warragamba River	227
	West Hornsby	Waitara Creek	4,840
	Winmalee	Nepean River	7,339
Shoalhaven City Council – treated wastewater from wastewater treatment plant	Berry	Broughton Creek	200
	Bomaderry	Abernathy's Creek	844
	Nowra	Shoalhaven River	1,873
Total			58,402

The volumes shown in the previous table reached the sea. They did not become inflows to downstream storages.

Treated water released from wastewater treatment plants to streams reaching downstream storages are detailed in the following table. The volume reported below has been deducted from 9.4 Rainfall runoff.

Details of discharge volumes to downstream storages are also available in line item 19.5.

Details of discharge volumes in downstream storages

Operator	Wastewater treatment plant	Discharging to watercourse	Reservoir receiving the discharge	Volume discharged during 2010–11 (ML)	Comments
Goulburn Mulwaree Council	Goulburn and Marulan	No	No	0	The plants received 2,517 ML Treated water was used for irrigation
Lithgow City Council	Lithgow	A tributary of the Coxs River	Lake Lyell	2,036	Metered inflows to the plants
	Wallerawang	Coxs River	Lake Wallace	177
Palerang Council	Braidwood	A tributary of the Shoalhaven River	Lake Yarrunga (Tallowa Dam)	87	Estimated volume from metered inflow to the plant
Wingecarribee Shire Council	Berrima	Olbury Creek	Lake Burragorang (Warragamba Dam)	101	Recorded from outflow meters
	Bowral	Wingecarribee River		1,594
	Braemar	Iron Mines Creek		1,013
	Bundanoon	Reedy Creek		283
	Moss Vale	Whites Creek	Medway	898
Total				6,189

 

Shoalhaven City Council telemetry system. Daily data registers in respect of the operations of the plants.

Shoalhaven City Council.

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.

Nil.

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

Data managed and maintained in an internal data management system by Operations Division (Systems Assurance) of Sydney Water Corporation (SWC). Metered data reported in SWC's Water Efficiency Report 2010–11

SWC.

Total metered volume of treated wastewater discharge to surface water from SWC's wastewater treatment plants and water recycling plants is provided. Water from St Marys Recycling plant was measured using SWC's Water Efficiency Report 2010–2011.

The flow of wastewater and recycled water 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 2010–11 from the data management system.

The main difference between treated wastewater and recycled water produced by SWC is quality, and quality is determined by the level of treatment. Recycled water is produced by treating water generated from sewage, greywater or stormwater systems to achieve high quality as required. Information on SWC's wastewater treatment levels in producing recycled water is available on their website.

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

The following table compares the value for the 2009–10 year reported in this account with the corresponding value reported in the 2010 Account.

 

Comparative information from the 2010 Account for line item 9.1

2011 Account line item	2010 Account line item	Value reported in the 2010 Account (ML)	Value reported in the 2011 Account (ML)	Additional information
9.9 Discharge from urban water system	13.7.1 Discharge of urban wastewater to connected surface water	54,576	56,556	Restatement: these two line items have been merged in the 2011 Account
	13.7.2 Urban recycled water discharge to connected surface water	1,980