Invention makes dirty water drinkable
Volume: 1, Issue 8 |  Tuesday, 20 July 2010 |  Craig McKune  |  1 comment

Image by Magnusfranklin

Fancy a drink from a stream known for harbouring rat-tailed maggots, faecal organisms and other dangerous microbes? Eugene Cloete does not appear fazed. Squatting by the infamous Plankenbrug River he fills a one litre bottle with water, stuffs what looks like a teabag into a screw-on cap, and drinks heartily through the nozzle, not 30 centimetres from the river.

Cloete is Stellenbosch University's dean of science, and the teabag is his new invention. He is also the chairman of the university's new Water Institute, one of 20 new initiatives Stellenbosch hopes will make it more useful to people.

"The primary objective we had in mind was to try find ways to meet the millennium development goal of halving the number of people, 1.2-billion, who don't have access to potable water," Cloete said. "The conventional thinking is to try to pipe treated water to them, but studies suggest we won't meet the goal like that. The idea then is that these filters bring the filtering process right to the point of use."

Cloete, working with Department of Microbiology researchers and university polymer scientists, did all of the testing in Stellenbosch's polluted Plankenbrug River, which is well-known for high levels of bacterial pollution.

The bag itself is made of the same biodegradable material as a standard teabag, but it is coated with ultra-thin nanofibres - 100th the breadth of a human hair.

"These filter out extremely small particles, and we incorporate a biocide in these fibres that will kill any microbes."

The bag is filled with active carbon granules - ash, essentially, standard in most water filters - which remove heavy metals and other harmful chemicals. The bags, which can filter three litres of water, cost about five cents to make, and would sell for about 15c. Once used, the bag can be tossed away and a new one fitted into the bottle neck - the bottle is purpose designed.

"We're setting up a spin-off company in collaboration with the private sector to manufacture the filters," Cloete said.

He had been negotiating with the Bill and Melinda Gates Foundation, which was interested in helping to distribute the bottles and filters in areas where water access defined daily life, particularly in Sub-Saharan Africa.

"They could be used in disaster areas, like after the earthquake in Haiti, where drinking water was a big problem."

But he also believed the filters would attract interest from offroad travellers, hikers, cyclists and for day-to-day use. He said he had had inquiries for them to be used in food packs for school children in rural South Africa and for soldiers' ration packs.

"We aim to role this out, bringing them to market, in the next two months."