South East Queensland
19.8 Other wastewater discharge
This line item consists of wastewater collection system discharges to landscape, where the primary purpose of the discharge was to discharge the effluent rather than irrigate agricultural land for economic benefit. This line item may include discharges to landscape that make their way into the groundwater.
Purposeful irrigation of agricultural land for economic benefit was included as the recycled water component of line item 19.4 Delivery to urban water system users.
Annual DERM Point Source Database wastewater treatment plant (WWTP) discharges to landscape were selected. Where the discharge did not match a recycled water supply from the utility data, it was decided that the discharge was for the purpose of discharging effluent rather than to irrigate agricultural land for economic benefit, and was included in this line item. Where a corresponding recycled water supply volume existed, this recycling was investigated and, if for economic benefit, the volume was included in line item 19.4 Delivery to urban water system users rather than this line item.
Assumptions, Limitations, Caveats and Approximations
It was assumed that where DERM Point Source Database data matched utility recycled water supply data that the effluent was recycled rather than discharged to landscape. Some inaccuracies may have resulted from this assumption.
The uncertainty estimate was not quantified.
This line item corresponds to line item 20.4.3 Other lumped wastewater discharge reported in the 2010 Account. The understanding of discharge points for WWTP in the SEQ region has developed since the 2010 Account publication.
In the 2010 Account a breakdown of discharge by WWTP was not available and a number of WWTP discharges were included in this line item. With a more accurate understanding of the discharge locations and individual WWTP discharge data, a number of WWTP discharges were moved to either line item 19.7 Wastewater discharge outside of region or line item 19.5 Urban water discharge to surface water for the 2011 Account.
The 2011 Account comparison year uses the volume reported in the 2010 Account, as a breakdown of WWTP discharges for the 2010 Account data were not available, corrections to the data could not be achieved. This has resulted in the numbers between the two years not being comparable.