The tough reality of city’s wastewater cost

Palmerston North residents are being asked to have their say about the most expensive project the city council has ever invested in – a new wastewater management system.

The project could add between $300 and $900 to the annual rates bill for every household.

Mayor Grant Smith said the numbers were sure to come as a shock to residents reeling from the effects of the Covid-19 lockdown.

But he was also optimistic the Government or other partners would come to the city’s aid to pay for the upgrades that could cost between $264 million and $765m.

The council had planned to take its short-list of six options out for consultation in March, but the lockdown delayed the process.

With a June 2022 deadline for applying for new resource consents to discharge wastewater to land, river or ocean, there was no more time to waste.

Deciding on a new treatment regime brings to a head nearly nine years of legal and environmental wrangles. It started with Horizons Regional Council telling the council to stop polluting the Manawatu¯ River in 2011, issuing and then withdrawing an abatement notice, and a commissioners hearing in 2014.

Horizons and the city council later agreed a path forward that removed the need for litigation. The city agreed to apply for a new resource consent by 2022, six years earlier than the current consent runs out, in exchange for Horizons dropping a legal case against it.

Investigations into the best possible options for future wastewater management got under way in 2017.

The council has spent nearly $1.6 million in 2019/20 on technical work and communications around the project.

The options being considered come with price tags much higher than the $128m estimated in the council’s longterm plan. All of them would retain the Totara Rd wastewater treatment plant in some form.

Option 1 would be the closest to business as usual, with nitrogen removed and improved phosphorus removal before discharge to the river.

Option 2 would see some treated wastewater diverted to a river discharge point downstream from the

piki bridge where the riverbed is softer with less gravel. When river levels were really low, some wastewater would be diverted to land. It would be possibly the cheapest option, bumping up rates by $300 to $450 a year.

The third option, and possibly the most expensive, would be discharging almost all wastewater to land, using the river only 3 per cent of the time when it was in high flow. A suitable land area the size of up to 3500 rugby fields would be needed, probably outside the city boundaries.

The fourth option would be something like a 60/40 split between land and river discharge.

The last two would be completely different – either infiltration into groundwater, or piping most of the wastewater out to sea.

The council wants to hear from people in Manawatu¯ and Horowhenua because the land or ocean discharge options would probably affect them.

The way consultation is done will depend on what Covid-19 alert level rules apply for the rest of June.

That could affect how many people would be allowed to attend a ‘‘town hall’’ style meeting in Palmerston North on Wednesday, June 17, and later meetings in Levin and Feilding.