All power to super dump's stench

Sydney Morning Herald
Tuesday 17/4/2007 Page: 1

THEY call it the void. A giant open-cut mine on the outskirts of Goulburn is slowly filling with Sydney's waste, but this super tip is also a new source of green power. When the switch is flicked at a small power plant nearby in about six months. methane from the decomposing waste will be burned to generate electricity.

The food scraps and paper a growing number of Sydneysiders throw out will be used to generate the electricity to power their homes. Methane is a greenhouse gas 20 times more potent than carbon dioxide. About 20 per cent of human-induced global warming since pre-industrial times has been attributed to methane emanating from landfills, coalmines, oil and gas operations, and agriculture.

Capturing the gas and using it to generate electricity prevents it from entering the atmosphere and displaces electricity that would otherwise have been generated by coal-fired power stations. What is good for the environment is also good for companies such as Veolia, the international waste and water group that owns the Woodlawn tip at Goulburn. Once viewed as nothing more than a problem that had to be buried, literally, waste is increasingly considered a valuable resource, Veolia says.

The company hopes to make money not just from selling methane-generated electricity into the national electricity grid, but also from turning organic waste into fertiliser. Hot water from waste processing could also be used to establish greenhouses and fish farms. Unlike traditional landfills, which capture the methane only when a tip is full, Veolia's team of engineering and environmental managers want to generate as much methane as possible and suck it from the decomposing waste while the tip fills.

They have designed a system of pipes that run horizontally and vertically through the waste that pumps the gas to their nearby power plant. Leachate in the pit - created when rain percolating through the waste reacts with decomposing material - is pumped through the layers of rubbish to speed up the decomposition, which in turn generates more methane.

Veolia has entered a long-term contract to provide the electricity to EnergyAustralia, which estimates that capturing gas from the landfill will reduce greenhouse gas emissions by more than 800,000 tonnes a year and generate 20 megawatts an hour, or enough green electricity a year to power 30,000 homes. Veolia also has State Government approval to build a 25-turbine wind farm near the Woodlawn tip, which would generate another 50 megawatts an hour.

But a $50 a tonne levy imposed by the NSW Government on waste that goes to landfill has prompted Veolia to look at ways of using some of the waste instead of burying it. Veolia's ambitious plans have not been without problems. Clyde and Auburn residents went to court several years ago in an unsuccessful bid to stop the construction of a waste transfer station at Clyde, from which the waste is sent by rail to the tip.

Veolia defends the efficiency of its transport system. It says the trains that transfer almost 9000 tonnes of waste from Clyde every week have taken 39,000 truck movements off the roads. South-western Sydney is likely to get another waste transfer station similar to that at Clyde under the company's plan to build a recycling plant at Woodlawn. The transfer station is expected to handle an extra 240,000 tonnes of rubbish a year that would travel to Woodlawn by rail. However, it is likely the waste would be delivered to the transfer station by trucks.