New treatment plant to reduce sludge

By Alecia Rousseau of the Manawatu Guardian

Palmerston North is one step closer to diverting 75 per cent of its waste from landfills by 2015 with the establishment of a new sludge treatment plant.

The Wetox plant, the first of its kind in New Zealand, was developed at Victoria University and officially launched this week at the Totara Road wastewater treatment plant.

Almost half a million tonnes of sludge enter the lower North Island's landfills, where its high phosphate content presents dangers to river health should it leach out. The new project aims to reduce the amount of sludge passing through the city's plant by recovering such phosphates, along with the alum used to treat it.

The Wetox technology uses high temperatures and pressures to break the sludge down into its components for extraction.

If everything goes to plan, there will be at least a 90 per cent sludge reduction, and at least 80 per cent of the alum will be recovered. The council hopes to sell the recovered phosphate as fertiliser.

Council water and waste services manager Rob Green said the intention would be to use the alum on site to reduce the costs of purchasing it.

"Phosphates will also be recovered, which is great news as it means the chances of these leaching into the Manawatu River from waste water are extremely minimal," he said.

Geoff Todd, chief executive of VicLink, which produced Wetox, said the new plant also provided a solution to headaches caused by having to get rid of the stuff.

"Waste water, water treatment and industrial processors that produce sludge face tighter constraints and rising costs of disposal," he said. "The Wetox system provides a cost-effective solution."

The plant received $1.1 million in funding from the Government's Minimisation Fund.

Palmerston North mayor Jono Naylor said the new scheme highlighted the need for more of this kind of problem solving.

"This kind of thinking is exactly what needs to be going on around the country," he said.

"Addressing the big issue with this unique solution ... makes us special."

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