Canberra
19.1 Evaporation from urban water system

Supporting information

a. Discharge to surface water from wastewater system

The total wastewater volume collected was 38,429 ML during the 2011–12 year. Approximately 88% of the collected wastewater discharged to surface water after treatment (34,325 ML).

During the 2011–12 year, approximately 11% of treated wastewater was recycled; and the rest was the losses. The following figure shows all the inflows and outflows associated with the wastewater system.

For more detail on a particular flow associated with the recycled water system, refer to the line item notes. Note that volumes annotated with an * indicate flows between sub-components and are not reported in the account. As such, these flows do not have an associated line item number.


Schematic diagram of water inflows and outflows during the 2011–12 year for Canberra's wastewater system. Line item numbers are provided in brackets.
Schematic diagram of water inflows and outflows during the 2011–12 year for Canberra's wastewater system. Line item numbers are provided in brackets.

b. Supporting information

This line item refers to the volume of water that was calculated as loss through evaporation at the Lower Molonglo Water Quality Control Centre (LMWQCC), Fyshwick Wastewater Treatment Plant (WWTP) and the Queanbeyan WWTP. The total volume reported in the 2012 Account is 3,838 ML.


Evaporation losses at water treatment plants
Treatment plant Evaporation loss
Fyshwick 274
LMWQCC 2,812
Urriara 0
Outward Bound  0
Queanbeyan 752
Total 3,838

Quantification approach

Data source

Water Data Warehouse.

Provided by

ACTEW Water.

Method

Reported volume is measured data retrieved from the ACTEW Water Water Data Warehouse. The calculated volume of water lost through evaporation in the treatment process at the LMWQCC, Fyshwick Wastewater, Urriara and Outward Bound treatment plants was calculated as the inflow to the plants, less the discharge to surface water, less the volume of recycled water.


Calculation of losses at the LMWQCC, Fyshwick, Urriara and Outward Bound wastewater treatment plants 
Calculation Component Fyshwick LMWQCC Urriara Outward Bound  ACTEW Water TOTAL
inflow   1,126 34,096 9 1 35,232
minus Recycled water 236 29 1 266
minus Discharge to surface water 31,255 9 31,264
minus Discharge to sewer 616 616
equals Losses 274 2,812 0 0 3,086


The calculated volume of evaporation and other system losses at the Queanbeyan WWTP was 752 ML. Evaporation was measured from four lagoons, two sludge lagoons and other smaller open water bodies such as aeration tanks. The moisture content of sludge was not included.

Assumptions, limitations, caveats and approximations

Nil.

Uncertainty information

The uncertainty estimate was not quantified.