Methane system tested

Ian Featherston
Ian Featherston
The $1 million system designed to burn off methane gas from the Dunedin City Council's Green Island landfill was fired up, briefly, for the first time on Friday.

Solid waste manager for the council, Ian Featherston, said gas from three or four bores was piped to an exhaust - an upstanding pipe with "what looks like a 44-gallon drum" at the top.

"It's not like a big orange flame on an oil rig. [The methane] is burnt inside this insulated area and all you see is the heat haze wafting out."

Mr Featherston said the next step would be to install monitoring equipment, in a few weeks, to find out more about the quantities of gas available from the landfill.

By the time the system was completed, the cost would be about $4 million.

Burning the methane from landfills is required under New Zealand waste and air regulations.

The CO2 created in the process was a less harmful "greenhouse gas" than the methane.

The new system - installed by Envirowaste and Delta over the last six months - replaces a $3 million system built in the 1990s but abandoned in 1998, after proving to be unviable.

Mr Featherston said the "landfill operating strategy" had been modified so that the new system "should work".

He hoped, ultimately, heat from the burning methane could be harnessed to produce electricity, as it is at other landfills in New Zealand. However, that would depend on the economics.

In 2007, the council rejected the electricity generation option as too expensive. The cost was estimated to be $8.7 million.

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