Wastewater being discharged into Cook Strait again after sewage leak

Wellington Water has said that screened wastewater is now being discharged into the Cook Strait again, following days of it being discharged near the shoreline on the South Coast

The Moa Point wastewater plant's lower floors completely flooded on Wednesday when sewage backed up in the 1.8km outfall pipe, sending raw sewage spilling out from a five-metre pipe directly into the southern coastline.

The flooding cause beach closures off the capital's south coast, with officials saying repairs "could take months".

In a statement today, Wellington Water Board Chair Nick Legget said that progress had been made overnight, with staff able to get the long outfall pipe partially operating and the screens at the treatment plant working.

“However, we are currently only able to pump 900 litres per second of wastewater through the long outfall pipe which is most of the wastewater during an average day, but during peak flows throughout the day we will need to use the short outfall pipe," Legget said.

"The team are working carefully throughout the weekend to increase the volume of flow through the long outfall pipe as much as possible, to reduce the use of the short outfall pipe."

Legget said he was unable to provide a timeline on when the issue would be resolved, saying the situation remained "complex".

Wellington Water said another one of its priorities was draining the clarifier tanks at the treatment plant, which contained biological matter unable to be removed by truck and instead would be drained through the long outfall pipe.

"It is important to remove this material as soon as possible before it has a chance to become anaerobic and septic."

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Drivers would also inspect diffusers at the end of the outfall pipe on Friday, with shoreline inspectors and debris clean-up on the coastline contuning three times daily.

Legget said the advice to the public was to avoid the coastal area until further notice, and not to collect kaimoana in the area.