A high-tech, low-cost disposable water 
 filter that fits into the neck of a 
 water bottle and delivers clean water as one drinks from it has been devel-oped and should be commercialised in the next few months.

Professor Eugene Cloete, microbiologist and Dean of the Faculty of Science at Stellenbosch University (SU), together with researchers from the Department of Microbiology and SU polymer scientists, recently patented the portable, easy-to-use and environment-friendly water filter bag, which looks like a tea bag.

The bag is filled with active carbon granules that remove harmful chemicals like endocrine disruptors. 
Cloete says that each “tea bag” filter can clean the most polluted water to the point where it is 100% safe to drink. Once used, the bag is thrown away, and a new one is inserted into the bottle neck.

The sachet combines years of funda-mental research on water purification, nanotechnology and food microbiology in a practical way. 
It aims to provide easy access to clean drinking water for vulnerable communities living near polluted water streams. 
There are also plans to commercialise the filter bag into a product that can be used by outdoor enthusiasts on hiking or camping trips.

As a past executive vice-president of global network of water professionals the International Water Association and a member of Coca-Cola’s global panel of water experts, Cloete believes water provision and sustainability go hand in hand. “The lack of adequate, safe and affordable water supplies impacts severely on vulnerable groups, such as the poor, the elderly, HIV patients and children,” he says.

A water security risk index of 165 nations, released by UK-based risk consultancy firm Maplecroft in June found that African and Asian nations had the most vulnerable water supplies, judged by factors such as availability of drinking water, demand per capita and dependence on rivers that flow through other countries. Cloete adds that more than 90% of all cholera cases are reported in Africa, and 300-million people on the continent do not have access to safe drinking water.

“The ‘tea bag’ filter can show the way forward, as it represents decentralised, point-of-use technology. 
“It can assist in meeting the needs of people who live or travel in remote areas, or people whose regular water supply is not treated to potable standards. 
“As it is impossible to build purification infrastructure at every polluted stream, we have to take the solution to the people,” he notes.

The invention has become one of the first significant projects of the recently established Stellenbosch University Water Institute, a transdisciplinary initiative established to intensify the search for lasting solutions to the country’s and the continent’s water challenges. 
Cloete, who also chairs the Water Insti-tute, says he got the idea for the filter 
during an introductory visit to the SU’s technology transfer company, InnovUS, 
18 months ago.

“I was shown the electrospinning technique of spinning ultrathin fibres on a nanoscale, developed by polymer scientist Dr Eugene Smit, of the SU Department of Chemistry and Polymer Science. My mind immediately started churning up the possibilities of how it could be used to clean polluted water,” he says.

A research team was put together and, after various trials and experiments, a filter sachet was developed that not only resembles a tea bag in shape and size, but is made of the same biodegradable material as off-the-shelf rooibos tea bags. The inside of the tea bag material is coated with a thin film of biocides encapsulated within minute nanofibres, which kill all disease-causing microbes.

“We tested the filter with water taken from a river in the Stellenbosch area. The samples were highly polluted with pathogens, but they came out completely clean on the other side,” says postdoctoral fellow Dr Michéle de Kwaadsteniet, who is working on the project with Cloete and Professor Leon Dicks, of the Department of Microbiology.

Postdoctoral fellow in the Department of Microbiology and a member of the water filter bag research team Dr Marelize Botes says that it is exciting to be part of a potentially life-changing project. “It is such an easy-to-use and practical solution to something that’s been a significant challenge for so long,” she notes.

The ‘tea bag’ filter is currently being tested by the South African Bureau of Standards, after which the team hopes to roll it out to various communities.

The Stellenbosch University Water Institute and its ‘tea bag’ water filter form part of SU’s Hope Project, a set of development goals aimed at improving the quality of life of people living in South Africa and on the rest of the continent.

SU rector and vice chancellor Professor Russel Botman adds that the university believes that science should serve the needs of society. “By aligning the expertise of our scientists with the national and global development agenda, we want to become more relevant to society,” he concludes.

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