South East Queensland
11.4 Wastewater collected

The volume for the line item during the 2012–13 year was 244,668 ML. It represents the volume of wastewater collected by water authorities: Queensland Urban Utility (QUU), Logan City Council, Redland City Council, Unitywater, Council of the City of Gold Coast, Toowoomba Regional Council, and South Burnett Regional Council, during the 2012–13 year.

The value represents the metered wastewater volume collected in the region. This volume includes wastewater discharged to the sewer after usage and any variation due to: (a) ingress of stormwater; (b) infiltration of groundwater; (c) wastewater overflows to stormwater; and (d) exfiltration of wastewater to groundwater.

Wastewater collected by water authorities

Water authority	Volume (ML)
QUU	128,293
Logan City Council	21,585
Redland City Council	11,355
Unitywater	27,749
Council of the City of Gold Coast	55,418
Toowoomba Regional Council	179
South Burnett Regional Council	89
Total	244,668

The volume of wastewater collected by the wastewater system during the 2012–13 year (11.4 Wastewater collected) was 244,668 ML. The majority of the outflow from the wastewater system (74%) was treated wastewater discharged to sea (19.7 Wastewater discharge outside of region); around 16% was discharged to surface water (19.5 Urban water discharge to surface water); and around 9 % was recycled. The remainder (1%) was a small volume of treated wastewater discharged to landscape and losses from the wastewater system.

The following figure shows all the inflows and outflows associated with the wastewater system. There was some unaccounted flow in the wastewater system that produced an error of  0.4% of total wastewater system inflows. 

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 asterisk (*) 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 2012-13 year for South East Queensland's wastewater system; line numbers are provided in brackets

Logan City Council; Queensland Urban Utilities (QUU); Redland City Council; and Toowoomba Regional Council: metered wastewater data  via Queensland Water Directorate (Qldwater)

Council of the City of Gold Coast: SWIM code data

South Burnett Regional Council: datasheet

Unitywater: Bureau of Meteorology code data

 

Council of the City of Gold Coast; Logan City Council; Queensland Urban Utilities; Redland City Council; South Burnett Regional Council; Toowoomba Regional Council; and Unitywater.

The volume of wastewater collected reported based on the wastewater flows metered at wastewater treatment plants.

The wastewater flows metered at wastewater treatment plants represent the total volume of wastewater accumulated resulting from: (1) wastewater discharge to sewer after usage; and (2) net inflow due to stormwater ingress and  groundwater infiltration into wastewater collection network, and wastewater overflows to stormwater and wastewater exfiltration to groundwater from the netwrok.  The development of methods for estimating stormwater ingress and groundwater infiltration and the overflows and exfiltration of wastewater would enable more accurate representation of the volume of wastewater collected (discharge of wastewater to sewer after usage) within the region. Such methods would also allow representation of the volumes representing stormwater ingress, groundwater infiltration, and the overflows and exfiltration of wastewater via the relevant line items.

The uncertainty estimate was not quantified.