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Knowledge Hub / The Network / Wastewater / Wastewater treatment plants / Moa Point Wastewater Treatment Plant

Moa Point Wastewater Treatment Plant

At the Moa Point Treatment Plant, sewage travels through a series of screens, tanks, bioreactors, clarifiers and ultraviolet treatments before being discharged as liquid into Cook Strait.

It was granted new consents on 11 May 2009. These consents will continue for 25 years (expire 11 May 2034).

In general, the consents allow WCC:

  • to continuously discharge up to 260,000 cubic meters per day of treated and disinfected wastewater into the coastal marine area via an existing submarine outfall,
  • to discharge up to 4500 litres per second of mixed disinfected, treated and milli-screened wastewater to the coastal marine area during and/or immediately after heavy rainfall, when the quantity of wastewater arriving at the Moa Point Wastewater Treatment Plant exceeds 3000 litres per second,
  • to occupy the foreshore and seabed of the coastal marine area with an existing submarine outfall pipeline,
  • to continuously discharge contaminants (including odour) to air from the Moa Point Wastewater Treatment Plant ventilation system.

Resource consents

Resource consent reports

Plant performance



Current Status: Non-compliant 
Period: October 2024

 

Commentary​

The plant remains non-compliant for suspended solids (90th percentile limit) and faecal coliforms (90-day geomean and 90th percentile limits). (see Items of significance)

 

Discharges

There was one consented wet weather discharge on 14 October.

 

Odour

There was one odour complaint in October relating to the Southern Landfill site and Careys Gully Sludge Dewatering plant.

 

Abatement Notice issued

GWRC issued an Abatement requiring the third and final phase of the IPS Riser project to be completed by 31 March 2025. 


Items of significance:

 

Effluent Compliance​

The return to service of clarifier #2 stabilised the biological process, although the refurbishment of clarifier #1 beginning in November will again reduce treatment capacity by a third. This may impact the process and timeline to compliance. The current daily results for suspended solids are trending back into compliance by end of December for both the 90-day geomean and 90th percentile limits. Daily results for faecal coliforms show spikes in results which is affecting the 90-day geomean and 90th percentile limits and are being investigated.

 

Inlet Pump Station (IPS) Project

Physical works for the third and final phase of the IPS project began in October. This involves the remaining four of 10 riser pipes being replaced, along with four of the 10 submersible pumps, strengthening the IPS’s resilience for high rainfall events.

 

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