Sydney
11.4 Wastewater collected
Supporting information
a. Sydney wastewater system overview
The wastewater system is one of three sub-components of Sydney's urban water system. The three sub-components are the:
- Urban water supply system
- Wastewater system
- Recycled water system.
In the Sydney region, wastewater is collected from users by the Sydney Water Corporation, Shoalhaven City Council or Wingecarribee Shire Council (11.4) and transferred to wastewater treatment plants throughout the region.There is also some stormwater ingress reported by Wingecarribee Shire Council which is considered a wastewater inflow (11.7).
During the 2011–12 year, 7% of treated wastewater was recycled; 78% discharged to the sea (19.7); and the rest discharged to inland surface water (19.5). 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 sub-components and are not reported in the account. As such, these flows do not have an associated line item number.
The Sydney region's wastewater system using data retrieved from Sydney Water Corporation, Shoalhaven City Council and Wingecarribee Shire Council
b. Volume of wastewater collected in the Sydney region
The volume for the line item is 601,502 ML.
A breakdown of the wastewater collected by the urban system is provided in the following table.
Council/Corporation |
Wastewater volume collected (ML) |
Sydney Water Corporation |
588,098 |
Shoalhaven City Council |
8,525 |
Wingecarribbee Shire Council |
4,879 |
Total |
601,502 |
A breakdown of the wastewater treated by Sydney Water Corporation and collected by Wingecarribee Shire Council is provided in the following tables. A breakdown of the Shoalhaven City Council wastewater volumes is not available.
Plant type | Watewater Treatment Plant | Volume of effluent treated (excluding volume of treated for on-site use) (ML) |
Water recycling | Bombo | 1,900 |
Castle Hill | 3,695 | |
Gerroa | 460 | |
Glenfield | 645 | |
Liverpool | 5,238 | |
Penrith | 9,856 | |
Picton | 1,028 | |
Quakers Hill | 14,282 | |
Richmond | 861 | |
Rouse Hill | 7,330 | |
St Marys | 17,277 | |
West Camden | 4,342 | |
Wollongong | 24,601 | |
Camellia1 |
2,156 | |
Wastewater treatment | Bellambi2 | 1,018 |
Bondi | 50,234 | |
Brooklyn | 100 | |
Cronulla | 23,288 | |
Fairfield2 | 3,543 | |
Hornsby Heights | 2,990 | |
Malabar | 195,446 | |
North Head | 162,071 | |
North Richmond | 417 | |
Port Kembla2 | 888 | |
Riverstone | 771 | |
Shellharbour | 7,743 | |
Wallacia | 372 | |
Warriewood | 8,092 | |
West Hornsby | 5,554 | |
Winmalee | 8,626 | |
Sewer mining3 | 803 | |
Modelled network wet weather overflows | 22,471 | |
Total | 588,098 |
1 Recycled water agreement - Veiolia accesses Sydney Water Corporation's secondary treated wastewater and further treats for Sydney Water Corporation's customers
2 A wet-weather wastewater treatment plant, which is only used during major storms
3 Volume of sewage supplied to other infrastructure operators
Wastewater treatment plant | Total wastewater treated in the 2011–12 year (ML) |
Berrima | 1,892 |
Bowral | 352 |
Bundanoon | 1,286 |
Mittagong | 1,220 |
Moss Vale | 129 |
Total | 4,879 |
Quantification approach
Shoalhaven City Council
Data source
Provided by
Method
This item represents the total metered volume of wastewater collected by Shoalhaven City Council's wastewater treatment plants.
The calculation includes:
- grease trap waste
- on-residential
- residential
- septic tank effluent
- septic tank sludge/pan
- tradewaste.
Assumptions, limitations, caveats and approximations
The volume of wastewater collected/treated at sewerage treatment plants may also include any net ingress of stormwater or groundwater to the sewer system.
Uncertainty information
The volume is based on measured data. Estimated uncertainty based on meter accuracy is +/– 5%.
Sydney Water Corporation
Data source
Provided by
Method
Volumes for both components have been derived from metered outflow data from the plants. The flow meter 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. From the data management system, data have been extracted for the reporting period.
Modelled wet weather outflows are determined by the hydraulic sewer system model. Wet weather overflow events are defined as sewage overflow that is not the result of an identified blockage in the Sydney Water Corporation's sewerage system or a system failure. It is a result of failure in the systems capacity. Wet weather overflow volume and events will be measured by the hydraulic system models as specified in the Environmental Protection Authority Sewage Treatment System Licences.
Assumptions, limitations, caveats and approximations
- The volume does not include water losses in the treatment process including biosolid removal, de-watering and evaporation.
- Total wastewater treated can include net ingress from stormwater and groundwater.
- At wet-weather wastewater treatment plants, wastewater treated usually also includes a certain volume of stormwater.
Uncertainty information
The volume is based on measured data. Estimated uncertainty based on meter accuracy is +/– 2%.
Wingecarribee Shire Council
Data source
Provided by
Method
This item represents the total volume of wastewater collected at wastewater treatment plants. The volume is derived from data from inflow meters at wastewater treatment plant where applicable.
Assumptions, limitations, caveats and approximations
Total wastewater received can include net ingress from stormwater and groundwater. Inflows to plants have only been measured at Moss Vale, Berrima and Bundanoon wastewater treatment plants. Therefore, treated volumes shown above are the same as discharge volumes shown under 'Volume of (treated) wastewater discharged to surface water' for these plants.
Uncertainty information
The volume is based on measured data. Estimated uncertainty based on meter accuracy and professional judgment is +/– 7%.