Projects / Karori Wastewater Tunnel upgrade

Karori Wastewater Tunnel upgrade

Overview
Current status
Background

On behalf of Wellington City Council, we are upgrading the wastewater tunnel to improve the performance of the network leading to the Western Wastewater Treatment Plant and reduce the risk of overflows into the environment.

Start Date
3/05/2023
End Date
30/09/2023
Contact:

If you have any questions about this work, please contact:

Wellington Water, 04 912 4400

Work has been completed. 

This project continues Wellington Water’s work on behalf of Wellington City Council to reduce wet weather overflows to the Karori Stream. 

The Western Wastewater Treatment Plant (WWTP) has the capacity to treat flows of up to 200 L/s. However, if the peak inlet flows exceed this level, any additional incoming flows are diverted to the 1000m3 tank at the WWTP. If the storage tank is full, partially treated wastewater is discharged to the main outfall. If the main outfall does not have enough capacity, fully treated effluent is discharged to the stream and the remaining volume is discharged to the main outfall.

This project will reduce the risk of discharges to Karori stream by enabling better management of peak inlet flows to the WWTP.