Wastewater discharge - Martinborough Wastewater Treatment Plant

The Team from Wellington Water

An ongoing issue at the Martinborough Wastewater Treatment Plant has again resulted in a discharge of partially treated wastewater into the Ruamahanga River. This occurred on Monday 27 January between 9.20am and 11.30am.

Wellington Water is sorry that this has happened again and for the delay in reporting the issue to the Council. Action is now under way to get in front of this issue and to improve protocols in communicating to both Council and customers.

Although discharging treated wastewater to the river is a consented activity under the right conditions, when the river is low these types of discharges are invariably a breach of resource consent.

The Martinborough Wastewater Treatment Plant will have a review in order for potential points of operational failure to be identified ahead of time; this work has been prioritised for the next few days.

This discharge event and the previous one involved issues with the irrigator, which meant that discharge to adjacent land didn’t happen. With the storage ponds being full and no discharge to land possible, the designed contingency is discharge to the river, which we know is unacceptable.

Authorities at Regional Public Health and Greater Wellington Regional Council as well as iwi and community liaison group representatives have been notified.

The first incident occurred between 9.45pm on Tuesday 14 January and 10am Wednesday 15 January 2020, this resulted in 90,000 litres of partially treated wastewater discharged to the Ruamahanga River.

This latest incident resulted in 100,000 litres of partially treated wastewater discharged to the river, as well as 300,000 litres of fully treated wastewater.

Due to the dilution factor in the river, it’s understood that public health and recreational water user risk from all discharges was negligible.

However, Wellington Water is committed to doing better with how wastewater discharges enter the environment and are working on options for this. A full incident response and investigation of the outcomes of this work will be released when completed.