Pilot plant heralds new era in sludge disposal

Wetox, a Viclink startup company, is working with Palmerston North City Council to pilot a groundbreaking new technology which not only aims to solve one of the world’s biggest pollution problems – sludge disposal – but also recovers valuable resources for re-use.


All wastewater treatment plants produce sludge – it’s a by-product of the treatment process that accounts for a third of the total waste volume going to landfills: about half a million tonnes per year just for the lower North Island of New Zealand. And the problem just keeps on getting bigger.


Determined to find a solution, innovative researchers at Victoria University of Wellington have used science to develop a new technology known as Wetox. It has the potential to reduce sludge volumes by over 90%, virtually eliminating the need to spread waste across paddocks or dispose of it in landfills – saving municipalities ever-increasing landfill charges and transportation costs, not to mention the pristine New Zealand environment. 

The unique Wetox process uses high pressure and extreme temperatures to break the sludge down into water, at the same time enabling valuable inorganic resources such as phosphate (a valuable and increasingly expensive fertiliser) to be released and recovered for re-use – providing a welcome revenue source for water treatment plant operators such as Palmerston North City Council (PNCC).


PNCC are the first to trial Wetox, with the launch of a $1.09 million pilot plant in May 2013. The pilot, which is funded by the New Zealand Government through its waste minimisation fund, is being trialled on a small percentage of Manawatu’s daily sludge; however, if successful, the Wetox technology could be rolled out not only across PNCC’s entire waste water treatment plant, but throughout similar plants across New Zealand. And with an estimated need for 10,000 more systems worldwide, a global market worth billions of dollars could follow.