Sunday, December 25, 2011

Researchers Use Recycled Glass to Filter Raw Water

A team of researchers from Ngee Ann Polytechnic has found a cheaper and more environmentally-friendly way to filter raw water - using recycled glass.

The project, called GLASSwater, has helped the polytechnic's Environmental & Water Technology Centre of Innovation (EWTCOI) secure S$10.3 million for more such industry projects over the next three years.

Central to the process is a porous ceramic membrane made of recycled glass.

Dr Gurdev Singh, who is leading the research team, expects the technology to drive down production costs considerably.

He said the current production cost of ceramic membranes is about S$100 to S$200 per square metre, as they are made from natural raw materials.

With the GLASSwater membrane, it will be two to three times cheaper, costing only S$50 to S$100 to produce.

Waste glass is also usually dumped and melted at high temperatures (1,600 degrees Celsius), consuming a lot of energy and emitting large amounts of carbon dioxide and other toxic gases.

With the new invention, waste glass will no longer be dumped and melted. Instead, GLASSwater can treated further before it is safe to consume.

Dr Singh said it is ideal for other applications where the water does not need to be so pure.

Car-wash companies can use the membrane to recycle water to wash cars.

The water can also be used for irrigation.

Dr Singh elaborated: "Besides its ability to eliminate solids and pathogenic bacteria that cause diseases like typhoid and cholera, the glass ceramic membrane also has a high flux, meaning water can flow through it very quickly. All you have to do is insert the glass ceramic membrane into a bottle cap and pour.

"Car-wash companies, for example, can recycle the huge amount of used water they generate by channelling it through the glass ceramic membrane system. Another possible application is to collect rainwater on rooftops, run it over a battery of glass ceramic membranes in the storage tanks, and channel it to a tap for gardening.

"GLASSwater is also suitable for irrigation where the prime concern is to remove the turbidity and bacteria. Ultimately, our project will help to maximise usage of a very precious resource - water."

The next stage is to improve the purification properties of the glass ceramic membranes to produce drinking water.

The latest S$10.3 million in funding for EWTCOI comes from SPRING Singapore and Ngee Ann Polytechnic.

Set up in 2006 under a strategic partnership between the polytechnic and SPRING Singapore, the EWTCOI serves as a one-stop centre to catalyse the growth of small and medium enterprises which tap on its technological capabilities to develop commercially-viable solutions.

To date, the EWTCOI has provided consultancy services to more than 150 companies and has also secured S$5 million to work on 18 research and development projects.

Koh Lee Chew from the Water Quality Monitoring and Detection Centre at Ngee Ann Polytechnic said: "We are trying to work with industry partners and hopefully, we can commercialise it. And of course, we would like ultimately for this system to be housed inside central kitchens like your canteens and food courts, and whatever energy that is harvested from this system can be plowed back to the kitchen again."


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