Wellington’s sewage plants ‘obsolete and outdated’

Tuesday, 19 November 2024

The Wellington region’s wastewater treatment plants are in poor condition, and there are not enough spare parts or backup capacity for upgrades or repairs.

That is according to a new report commissioned by Wellington Water and multinational wastewater plant operator Veolia into the running of the plants, primarily blaming their recent multiple failures on equipment that was ageing or in “poor condition”.

Wellington Water’s acting chief executive Charles Barker and Veolia’s New Zealand country director Emma Brand warned residents, local council and mana whenua that they should expect “unreliable compliance” until they completed upgrades.

The report by Roly Frost and Raveen Jaduram, announced in May and dated August, was a follow-up to their 2021 review that highlighted a “dysfunctional” relationship between Wellington Water and Veolia.

Woes at the four regional plants – Porirua, Seaview in Lower Hutt and the Western and Moa Point plants in Wellington City – included foul smells, unauthorised discharges into nearby streams and sea, as well as delayed sewage leak notifications.

Their latest report said the plants’ equipment like pumps, blowers and aerators was “obsolete and outdated” and “prone to failure”.

There was no clear responsibility about who should be in charge of keeping tabs oncritical equipment or lead renewal programmes, and controls for staff to detect and stop treatment plants from breaching compliance early were non-existent.

Because much of the equipment was obsolete, spare parts were hard to come by and there were long delivery times. It meant it was harder for frontline staff to operate, requiring them to “demonstrate strong sense of urgency in responding to failures”.

“There is a lack of advanced monitoring and controls, preventing early detection and intervention to avoid non-compliance,” the report read. “There is evidence that operational staff lack understanding of resource consent conditions and the compliance implications of equipment and process failures.”

The Porirua plant ‒ which had issues with clarifiers not filtering out solid clusters of bacteria known as ‘sludge’ from wastewater or removing enough water from the sludge to be taken to the landfill ‒ was considered “in the best condition” out of all four plants.

Equipment at the other three plants needed “substantial replacement and renewal”.

Barker and Brand accepted the findings, with some caveats, saying upgrading the plants required “significant investment”.

The Post previously reported Wellington Water was spending $13 million to address Seaview’s odour problems, and a new outflow pipe to prevent sewage discharges could cost at least $1 billion.

The under-construction sludge minimisation plant at Moa Point carried a price tag upwards of $400m.

“Not having the needed level of investment in the past means we have a growing backlog of work to get the plants up to reliable performance,” they said. “Continued deficits in funding means ongoing delays in getting this work done.”

Even if there were dedicated funds, the upgrades would take some years: “The renewals work required to bring the plants up to a reliable level of compliance needs to be staged as the plants must remain operating while the work is undertaken.”

Frost and Jaduram’s latest report also said while there had been improvements since their 2021 review, there was “evidence of lack of trust” between the two organisations and “insufficient” efforts to meet standards.

Veolia needed to use its global expertise to take on local challenges such as making sure their staff were able to staff handle equipment prone to failures, they concluded, and Wellington Water should improve its contract management practices to enable a more collaborative relationship.

“This is a challenging task as the contract has not been written to be executed in a collaborative manner.”