Western Wastewater Treatment Plant
At the Western Treatment Plant, sewage travels through a series of screens, tanks, bioreactors, clarifiers and ultraviolet treatments before being discharged as liquid into Cook Strait in the vicinity of the Karori Stream Mouth.
The Western Treatment Plant was granted new consents on 28 July 2010. These consents will continue for 25 years (expire 28 July 2035).
In general, the consents allow WCC to:
- discharge of treated and partially treated effluent through an existing outfall,
- to discharge mixed disinfected, treated and milli-screened wastewater during and/or immediately after heavy rainfall,
- the discharge of contaminants to the air,
- and permission to occupy the coastal marine area with an outfall structure.
Resource consents
WGN060283 [35675] Discharge of Partially Treated WW to Fresh Water (Western WWTP)
WGN020236 [22098] Land Occupation by Outfall Structure (Western WWTP)
WGN060283 [25227] Discharge of Treated WW to Fresh Water (Western WWTP)
WGN060283 [25230] Contaminants Discharge to Air (Western WWTP)
WGN060283 [35255] Discharge of Treated WW to Coastal Marine Area (Western WWTP)
WGN060283 [35674] Discharge of Partially Treated WW to Coastal Marine Area (Western WWTP)
WGN160340 [34178] [34179] Pipeline Maintenance Land Use (Western WWTP)
Resource consent reports
Annual Reports:
Western Wastewater Treatment Plant Annual Resource Consents Report 2020/2021
Western Wastewater Treatment Plant Annual Resource Consents Report 2019/2020
Western Wastewater Treatment Plant Annual Resource Consents Report 2021/2022
Western Wastewater Treatment Plant 2022/ 23 Annual Resource Consents Report
Plant performance
Current Status: Non-Compliant
Period: December 2023
Commentary:
The plant remains non-compliant for Biochemical Oxygen Demand (BOD) Geomean limit. Effluent quality has improved, and the current projection indicates effluent compliance in February.
Please Explain letter:
A response for the undisinfected discharge on 24 November was submitted to GWRC within the required timeframe.
Discharges:
No discharges in December.
Items of significance:
Outfall Repair:
The completion date for the main outfall pipeline has been delayed with work currently on hold. Fully treated effluent from the plant will continue to discharge into the stream until repairs are complete.