Converter using pyrolysis turns waste into gas

Via stuff.co.nz, by Paul Easton – The Dominion Post, 24/05/2010

A new plant that turns plastic, food scraps and even human waste into fuel is humming away on the Kapiti Coast.

“We pick it up where everybody gives up,” SpectioNZ co-director Murray Friar said. The Wellington company received funding from the Foundation for Research, Science and Technology to take the plant from the drawing board to reality.

A trial converter is being tested at Paraparaumu’s wastewater treatment plant.

Dried human waste is mixed with plastic and formed into rods which are fed into the unit, where they are heated in the absence of air, in a process called pyrolysis.

As the material heats up, its carbon breaks down and is converted into gas.

That gas, which includes methane, could be used to power turbines and make electricity.

Any carbon-based material could go into the converter, SpectioNZ co-director Mike Henare said.

That meant New Zealand’s mountain of plastic and organic waste could one day be turned into fuel. “Three million tonnes of waste goes into landfill each year. Of that, 1.8 million is organic, so there’s the potential to divert that much. Successful development of the system could mean we no longer have to export waste to China.”

The next step was to develop an industrial version of the converter, with a 100 kilowatt power supply, compared to 1kW on the trial version.

Kapiti Coast District Council provided the venue – and the raw material – for the trial. Mayor Jenny Rowan said the region was focusing on sustainable development and exploring new technology.

About 13,000 tonnes of kerbside recycling is collected each year in Wellington. Much of that is sent to China.

CitiOperations manager Mike Mendonca said the council hoped to process more recycling locally.

The trial processing plant at Kapiti was “clever technology”, he said. “It is yet to be proven on an industrial scale so our approach is one of cautious optimism.”