This line item comprises six different data-sets. The method for each data-set is shown below.
Quantification approaches are not provided because the volume discharged was zero.
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.
The volume was estimated from measured data. Uncertainty is ungraded.
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.
Database maintained as spreadsheets.
Palerang Council.
For 2009–10, 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.
The volume was estimated from measured data. Estimated uncertainty based on meter accuracy and professional judgment is +/–10%.
Nil.
Shoalhaven City Council.
Outflows from wastewater treatment plants were measured as follows:
The volume is based on measured data. Estimated uncertainty based on meter accuracy is +/–5%.
Nil.
Data managed and maintained in an internal data management system by Sydney Water Corporation’s (SWC) Operations Division.
Sydney Water Corporation.
The value represents the sum of total metered volume of treated wastewater discharge to surface water from wastewater treatment plants and water recycling plants managed by Sydney Water Corporation.
The flow of wastewater from the plants was measured using flow meters. These measured data are continually monitored and recorded. The data is 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.
The volume is based on measured data. Estimated uncertainty based on meter accuracy is +/–2%.
Nil.
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.
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.
Nil.