Supporters of a proposed $3.7 million upgrade of the Takaka wastewater plant say it will be more environmentally friendly, but some residents remain concerned.
The Tasman District Council has considered a range of options, including whether a new plant should be built, but has settled on improving the existing facility at Haldane Rd, near the Takaka River.
Public submissions on the proposal close at the end of the month.
An upgrade is needed to meet demands from a growing Golden Bay population, and to improve the quality of the discharged effluent, which currently does not meet consent requirements.
Golden Bay Community Board member Mik Symmons said the quality of the water from the upgraded plant would be far better.
The installation of plastic baffles in the two treatment ponds would allow more time for bacterial action and ultraviolet light from the Sun to work on the wastewater, he said.
The effluent would then flow into an upgraded reed bed system containing 14,000 new native plants to remove nutrients. The current reed beds had not worked well because of damage from floods and pukekos pulling them out, Mr Symmons said.
The final stage would see the effluent pumped into rapid infiltration basins - stone-lined pits - that would further clean it.
Hayley Gale, who lives in Feary Cres near the plant and spoke out against the redevelopment two years ago, said she was still not happy with it being so close to homes, but appreciated that some compromises had been made. An initial design had proposed a pond even closer to the homes, but that was dropped.
Ms Gale said she would like Takaka water bores to be periodically tested to ensure the water was safe to drink.
"We have beautiful water in Takaka. It's the best water in the country, and it would be really sad if that water was polluted."
A long-time critic of the wastewater plant, Bill Wallis, who lives five kilometres away, believed the plant's location was linked to low shellfish levels in Golden Bay. "From talking to fishermen and mussel farm owners, shellfish are declining," he said.
However, he was encouraged that the upgrade would include the reed grass and rapid filtration systems.
Tasman district councillor Martine Bouillir, who chaired the working party overseeing the upgrade, said she was happy with the environmental sustainability and cost-effectiveness of the proposed new plant.
"There will be lots of checks and balances and a back-up plan should any of the testing ever hint at being borderline.
"We will have a much-improved system to our current outdated, overloaded plant."
Dugall Wilson, programme manager for council engineers MWH, said the cost of the $3.7m project included site investigations, land purchase, design, consenting, and the physical work associated with the upgrade.
"The cost of the treatment plant upgrade is expensive, but the scale of upgrade is what is needed to safeguard the precious natural environment of the Takaka River.
"This is paid for under the existing district-wide pan charge."
Mr Wilson said the working party considered the location of the plant in great detail, before concluding that upgrading the existing site was the best option, primarily due to the cost of building a new facility.
"If council were to buy land somewhere else and build a treatment plant from scratch, it would be more expensive than the current upgrade."
Submissions on the proposal close at 4pm on November 30. They can be made through the council's website, tasman.govt.nz.
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