Bacteria to hold up walls, purify water?

Shobana Kesava, Straits Times 6 Nov 08;

IMAGINE a dam held together by bacteria. Or microbes turning a fetid lagoon into a source of crystal clear water.

Researchers discussed ideas like these yesterday during a gathering of industrialists, scientists and policymakers.

The four-day International Solid Waste Association World Congress 2008, which ends today, attracted about 1,000 participants from around the world.

While several concepts raised may seem torn from the pages of a science-fiction novel, some are close to becoming a reality.

Research is already under way at the Nanyang Technological University (NTU) on a process called biocementation, which uses bacteria to bind particles of sand together.

Under the right conditions - such as the presence of iron- based salts, acids and pressure - it already happens naturally. Scientists are looking for ways to whittle down the time it takes from years to just hours.

The bonds are so strong that they can hold up reservoir walls or prevent landslides, researcher Volodymyr Ivanov said.

Associate Professor Ivanov expects his work with an earth science expert, Associate Professor Chu Jian, also from the NTU's School of Civil and Environmental Engineering, to get started next year if funding comes through.

Meanwhile, the duo are also looking at turning bacteria that live in plant waste into water purifiers.

The microbes, which are harmless to people, can not only be combined with mineral salts to sweep away suspended particles but also clump together toxic algal blooms and other contaminants.

The bacteria-based cleaning system could be at least seven times cheaper than current methods which introduce artificial chemicals into the water, said Prof Ivanov.

He is now looking for funding from private and public organisations.

Experts also talked yesterday about other aspects of waste management.

Dr John Keung, chief executive officer of the Building and Construction Authority, said Singapore is committed to studying how new and recycled materials can be used in construction.

That includes funding for research that can contribute to better construction methods or those that will enhance the urban landscape.

The Government's commitments stem from a drive to reduce waste and come in the wake of rising construction costs, including price hikes for materials like sand.