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  The Straits Times 9 Feb 06
Leftover rice, chicken bones may soon light up your home
by Radha Basu

SCIENTISTS at Nanyang Technological University (NTU) have found a way to convert food waste such as vegetable peels, leftover rice and chicken bones into biogas and hydrogen.

These could be alternative energy sources in a world fast running out of oil. The food waste now burnt in incinerators could end up lighting homes and even running gas-powered cars in the future. The university began building a trial plant this week to test the technology and is already in talks with a local company to commercialise it, if the pilot proves successful.

Associate Professor Wang Jing-Yuan, who is leading the project, said the technology is important for three reasons.

First, in a land-scarce island, it converts mountains of food waste into gas, thereby reducing the need to build more incinerators. Second, it could also help the food industry save about $2.5 million a year in waste disposal fees. And finally, both biogas and hydrogen hold tremendous promise as alternate fuels of the future.

Biogas can be used to generate electricity. Hydrogen can be used to power cars and to cool or heat up homes. However, it will still be a few years before such hydrogen applications become commonplace. The pilot plant will initially be used to produce only biogas, said Prof Wang, who teaches at NTU's School of Civil and Environmental Engineering.

'Once hydrogen-powered products are commercially available, we could begin producing hydrogen as well,' he added.

The $1.6 million plant is being funded by the National Environment Agency (NEA) and The Enterprise Challenge (TEC), an initiative under the Prime Minister's Office to fund innovative research projects.

Both NEA and TEC believe that one of the project's biggest advantages is that it will help manage Singapore's food waste problem. According to NEA, Singapore produced nearly 1,400 tonnes of food waste - enough to fill about 200 garbage trucks - every day last year. Almost all of it was burnt in incinerators.

TEC estimates show that recycling food waste can reduce the load on incinerators by up to 20 per cent.

Prof Wang said: 'Diverting food waste to our NTU plant will thus definitely save energy and enhance the efficiency of incinerators.'

He and his team are using three different groups of bacteria that break up food waste first into acid and then into methane gas in a process known as anaerobic digestion. The reaction takes place in airtight steel vats. While the process is not new, it used to be very slow, with the bacteria requiring two to three months to convert waste to gas. But by separating the various bacteria into different airtight vats, the NTU team can convert the waste in one or two days.

A local renewable energy company, Lionapex Engineering, is helping NTU to test the technology. 'We are confident that we can commercialise this technology by next year,' said Lionapex's project manager Rene Glauser. The company also wants to export the technology to other countries in South-east Asia.

According to the company, a tonne of food waste could produce enough energy to light 1,000 60-watt bulbs for two hours or run a gas-powered car for 700km. 'This may not seem like much but remember, earlier the food was simply being burnt,' said Mr Glauser.

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