Food-powered fans,at your hawker centre?

Lin Yanqin, Today Online 11 Sep 08;

THE food scraps you leave behind on the hawker centre table could soon become the key ingredient in keeping the lights on and the fans whirring.

With the combined efforts of Republic Polytechnic and Ecovac systems — and funding from the National Environment Agency — hawker centres could one day become self-sufficient in energy, by processing their own food waste.

Such is the vision of Ecovac director Jenson Chia and RP professor Wong Luh Cherng who, together with RP students, are working to pilot this system at one hawker centre come November.

“At a push of a button, the hawker’s waste will be sucked and collected into a bioreactor,” said Mr Chia.

The waste is then processed by the bioreactor to produce methane to generate electricity. The waste can also be recycled for use as fertilisers or processed into biofuels.

The bioreactor, said Dr Wong, will be located at the hawker centre itself — unlike most current bioreactors which are usually larger-scale systems that collect waste and generate electricity at a centralised location.

With the polytechnic aiming to make “Converting Wastes to Resources” its niche, its inaugural Environmental Technology Day held yesterday showcased projects by its Environment Science students.

One other project, also overseen by Dr Wong, will make use of plant compost to dehumidify air, improve air quality and make the cooling of air a less energy-intensive process.

“If air is dehumidified before being fed into air-conditioning systems, the air-con does not have to remove the moisture from the air before cooling it, and that reduces the energy used,” said Dr Wong.

The plant compost — to be collected from Admiralty Park adjacent to the school — will be treated to produce gases that generate heat, so as to regenerate the desiccators — materials that absorb moisture from air.

These desiccators can then be used repeatedly to dehumidify air.

The polytechnic plans to pilot the system on its premises. “We will find out if the energy that can be saved will compensate for the energy used in the process,” said Dr Wong. “If there are savings, it can be marketed to the public.”

Marketing such products is often the hardest part, said Mr Tan Hai Woon, chief technological officer of Alpha Synovate — which makes biodiesel from used cooking oil.

“The science was the easy part,” he said at the event. “If there is no market, you have to build it ... it’s important to reach out to the community to create awareness.”