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Innovative technology piloted at Rotorua

Thursday 2 June 2011, 8:30AM

By Rotorua District Council

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ROTORUA

Yesterday (Tuesday 31 May) the Minister for the Environment Hon Dr Nick Smith opened a pilot plant that will test an innovative process converting biosolid waste into valuable chemical products.

Opening of the pilot plant at Rotorua District Council’s wastewater treatment plant is a milestone event in a research project involving Crown Research Institute Scion and the council, who joined forces in 2008 to develop a new approach to the management of organic waste.

The thermal oxidation pilot plant has been developed by Scion as an initiative of the ‘Waste 2 Gold’ biosolids research programme into organic waste utilisation.

Scion’s chief executive Dr Warren Parker says the new process could revolutionise the way sewage biosolids are managed.

“Switching on the pilot plant is a hugely exciting step. Soon we’ll be able to really see how well the technology can work outside the laboratory”, he says.

The purpose of the pilot plant is to determine if the technology could work at a full commercial scale. The pilot plant uses thermal deconstruction to “cook” the biosolids (sewage sludge) and break them down into re-useable chemicals and other by-products. These can be used for fertilisers or in the production of bioplastics and biofuels.

“If successful, a full-scale plant in Rotorua could initially remove thousands of tonnes of biosolid waste going to landfill each year, and ultimately achieve cost reduction and value creation of around $4 million per year for the council and community,” says Rotorua District Council chief executive Peter Guerin.

“This really brings the concept of ‘Waste 2 Gold’ to life with significant benefits for ratepayers and for the environment.”

The pilot plant will initially operate for 12 months. Depending on the results, the next stage will be to construct a demonstration plant, sized to handle all of the biosolids from Rotorua’s wastewater treatment plant.

Rotorua District Council sees the potential of the technology to not only improve its waste disposal processes but to provide a revenue source from the converted waste. Rotorua has approximately 8,500 tonnes of biosolid waste going to landfill every year at a current cost of approximately $920,000. This project has the potential to further reduce all organic waste going to landfill.

Rotorua is a good model for many cities in New Zealand who face the same challenges for disposing of biosolids and other municipal wastes. The technology could be implemented in other urban centres to reduce the volumes of biosolid going to landfills, by up to 30-fold.

The technology has applications beyond sewage biosolids. Scion says research shows that the same technology could also be used for managing organic wastes from food and industrial processors.

“The growing waste streams from expanding industries such as pulp and paper, agriculture, dairy, meat and fruit processing represent a tremendous potential resource for New Zealand that can be tapped into by environmental technologies like those developed through the Waste 2 Gold biosolids research programme.

“Also, greenhouse gas emissions and the risk of contaminating leachates arising from organic wastes will be substantially reduced,” says Dr Parker.

The technology was originally developed through a programme funded by the Foundation for Research, Science and Technology (now the Ministry of Science and Innovation). Last August the Ministry for the Environment committed to an investment of up to $1 million over two years under its Waste Minimisation Fund to support further development of the technology.