Singapore's warm weather helps in treatment of waste-water

By Wong Mun Wai, Channel NewsAsia
05 June 2007

SINGAPORE: Singapore is making the most of its tropical location, to bring down cost and improve efficiency, in the treatment of waste-water.

Experts say a warm temperature can help to speed up a particular type of processing, which does not use air.

And this in turn, produces more electricity that can be used in treatment plants.

The Public Utilities Board (PUB) is happy with the results of its lab tests.

It is treating waste-water, the anaerobic way, which means without using air or oxygen.

And in high temperature - the process has added benefits. The result - the waste-water ferments faster.

The fermentation produces a mixture of methane and carbon dioxide, called biogas, and the process does not consume energy.

"There's no air required so I don't incur any energy. So from that digestion process, you create biogas. From that biogas, you use it to produce power," said Harry Seah, Director, Technology & Water Quality, PUB.

And that power can be turned into electricity... which can be used to run the treatment plant.

Currently, these treatment plants get a quarter of their energy by using sludge as a fuel.

But when the anaerobic treatment method is rolled out, the PUB hopes it can meet half of the plants' energy needs.

But the roll out of the method is likely to be years away.

The laboratory tests have yet to reach pilot testing and a large scale test plant.

The PUB, though, sees the investment as worthwhile and says it is one of the long-term areas of treatment it is looking at for waste-water.

And other tropical countries can tap into the process too.

As for Singapore - the PUB predicts that as the demand for NEWater or recycled drinking water rises, the water-treatment plants will be able to produce NEWater at a lower cost. - CNA/yy