A phantom dumper is still at large in Wellington where an illegal waste discharge almost caused a sewage treatment plant failure at Karori this week.
A load of concentrated organic matter dumped into the sewer system blocked intake screens at the western treatment plant.
Veolia Water was able to divert regular wastewater into a storage tank used during heavy rainfall, while it worked to clear the screens.
The tank was 91% full before flow was restored, narrowly averting the need to discharge the partially treated wastewaster to the south coast via an outfall pipe.
Wellington City Council says someone has illegally been putting organic waste into the Karori sewers for months but where it's coming from and who's responsible remains a mystery.