Sydney
19.5 Urban water discharge to surface water

The volume of water discharged from urban wastewater systems during 2010–11 was 64,591 ML.

A breakdown of treated water from wastewater treatment plants and water recycling plants discharged to the streams is provided in the following table. The discharged volume is a decrease to the water distribution system store.

Breakdown of treated and recycled water that was discharged to surface water

Plant operator and description of wastewater discharge	Plant	Discharging to watercourse	Volume discharged during 2010–11 (ML)
Goulburn Mulwaree Council — treated wastewater from wastewater treatment plants	Goulburn and Marulan	Not applicable	01
Lithgow City Council — treated wastewater from wastewater treatment plants	Lithgow	A tributary of the Coxs River	2,036
	Wallerawang	Coxs River	177
Palerang Council — treated wastewater from wastewater treatment plants	Braidwood	A tributary of the Shoalhaven River	87
Shoalhaven City Council — treated wastewater from wastewater treatment plants	Berry	Broughton Creek	200
	Bomaderry	Abernathys Creek	844
	Nowra	Shoalhaven River	1,873
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	Boundary Creek	15,989
	St Marys	South Creek	3,662
	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
Wingecarribee Shire Council — treated wastewater from wastewater treatment plants	Berrima	Olbury Creek	101
	Bowral	Wingecarribee River	1,594
	Braemar	Iron Mines Creek	1013
	Bundanoon	Reedy Creek	283
	Moss Vale	Whites Creek	898
Total			64,591

 ¹2,517 ML was received at the plants for treatment. All treated water was used for irrigation.

Wallerawang Wastewater Treatment Plant receives wastewater generated from supplies made to the Lithgow City Council's distribution system from the Fish River Water Supply Scheme. Lithgow Wastewater Treatment Plant receives wastewater generated from supplies made to the distribution system from Oakey Park Water Treatment Plant. Wastewater received at these wastewater treatment plants includes inflow and infiltration resulting from stormwater.

Treated water released from some of the wastewater treatment plants included in the above table becomes inflow to downstream storages (counted in line item 9.4 Runoff to surface water)  as shown in the following table. (Line item 9.9 does not include these releases and, therefore, the volumes for the line item 19.5 and line item 9.9 are not equal.)

Treated wastewater released from wastewater treatment plants received at storages

Wastewater treatment plants releasing treated water	Reservoir receiving treated water	Wastewater treatment plant operator	Reservoir managing authority
Lithgow	Lake Lyell	Lithgow City Council	Delta Electricity
Wallerawang	Lake Wallace	Lithgow City Council	Delta Electricity
Berrima, Bowral, Braemar and Bundanoon	Lake Burragorang (Warragamba Dam)	Wingecarribee Shire Council	Sydney Catchment Authority
Moss Vale	Medway	Wingecarribee Shire Council	Wingecarribee Shire Council
Braidwood	Lake Yarrunga (Tallowa Dam)	Palerang Council	Sydney Catchment Authority

Data spreadsheets.

Lithgow City Council.

Flows were measured by water channel and height sensors, and converting water level to a volume in a spreadsheet using a rating table.

Wastewater received at Lithgow and Wallerawang wastewater treatment plants includes inflow and infiltration resulting from stormwater, in addition to wastewater generated from potable water supplies made to the water distribution system. Therefore, all of these sources contribute to the volume of treated wastewater released from the plants to the streams.

The volume was estimated from measured data. The uncertainty was not quantified.

Database maintained as spreadsheets.

NSW Office of Water.

For 2010–11, the wastewater treatment plant (now decommissioned) did not have any dedicated flow measurement at the outlet. The outflow from the plant was from a tertiary pond system. Measurement was made at the inlet to the plant only and this was done by an ABB Magmaster-type flow meter. The inflow measured from the flow meter has been approximated to the outflow, disregarding any inflow that may be lost through evaporation, or that may be supplemented through rainfall or infiltration to the pond system. 

Nil.

The volume was estimated from measured data. Estimated uncertainty based on meter accuracy and professional judgment is +/– 10%.

Shoalhaven City Council telemetry system. Daily data registers from the plant operations section.

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.

Sydney Water Corporation.

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%.

Supervisory Control and Data Acquisition (SCADA) data records from wastewater treatment plants.

Wingecarribee Shire Council.

The value represents the total volume of treated wastewater discharge to surface water from wastewater treatment plants.

The flow of wastewater from the plants was measured using ABB Magmaster flow meters installed on-site. The data from the flow meters are continually monitored and recorded.

Nil.

The volume is based on measured data. Estimated uncertainty based on meter accuracy and professional judgment is +/– 7%. External flow verification audits for the flow meters are conducted annually by Hydrometric Consulting Services.

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 19.5

2011 Account line item	2010 Account line item	Value reported in the 2010 Account (ML)	Value reported in the 2011 Account (ML)	Additional information
19.5 Urban water discharge to surface water	20.4.1 Discharge of urban wastewater to connected surface water	59,475	61,455	Line item presentation: these 2 line items have been merged for the 2011 Account. The amended value is the merged volume
	20.5.1 Urban recycled water discharge to connected surface water	1,980