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 Wellington City Council 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.