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SOUTH AFRICA: ‘Tea Bag’ Filter Provides Safe Drinking Water

Chris Stein

JOHANNESBURG, Aug 30 2010 (IPS) - Though it may look like a tea bag, straining water through this recently developed filter could provide a cheap, easily replenished source of water for those who need it most.

The unique device, developed at Stellenbosch University in South Africa, is no ordinary tea bag. It is a sophisticated yet inexpensive water filter that fits into the neck of a bottle and can quickly purify drinking water.

And this filter could provide a short-term solution for those without access to clean drinking water, experts say. Though, the water experts stress, it is not a replacement for water-purifying infrastructure.

Although the filter is yet to be manufactured on a large scale, it could possibly play a role in combating diseases caused by the consumption of unsafe drinking water. According to the United Nations, just over one billion people worldwide lack safe access to drinking water and more than two million people, mostly in developing countries, die each year from diseases associated with poor water and sanitary conditions.

The filter is composed of three integral parts, making it unique among filters, according to Professor Eugene Cloete, dean of the Faculty of Science at Stellenbosch University and developer of the filter.

Similar to other purification devices, a web of nanofibers and activated carbon catch bacteria from the water, said Cloete, one of South Africa’s leading water researchers and former vice-president of the International Water Association.

But what makes this filter unique is the inclusion of a biocide chemical in the filter, which kills any pathogen caught within, Cloete told IPS.

“Bacteria and viruses can’t move through, and then we kill them so they don’t concentrate inside the filter,” Cloete said. “There’s nothing like this in the world.”

In South Africa, efforts to bring clean water to rural or impoverished communities have been hampered by a lack of engineers in municipalities, as well as inequality between the infrastructures of cities and rural areas, according to Sharon Pollard, a programme manager at South Africa-based NGO Association for Water and Rural Development.

“Of 351 local municipalities, about six have engineers on staff,” Pollard said. “The infrastructure in the former homelands is way worse than in suburban Johannesburg, for instance.”

In areas without proper sanitation, Pollard said people relied on overpriced, informal water vendors, or on a few public pipes that provide clean water.

One of the advantages of the ‘tea bag’ water filter is that it is portable and can be used by people travelling to areas without clean water, or those who do not have a regular clean water supply. “It is simply impossible to build purification infrastructure at every polluted stream. So we have to take the solution to the people,” Cloete told online magazine Science in Africa.

In tests, Cloete told IPS, the filter removed most of the bacteria from river water, and was capable of stopping common pathogens like salmonella. “We have tested a whole shopping list of bacteria,” Cloete said. “It physically doesn’t get through (the filter).”

So far, the device has received interest from retail outlets, NGOs and philanthropists, Cloete said. As yet no decision has been made on how the filter will be distributed.

The challenge would be how best to get the filter to those who need it most, said Thomas Levine, an economist at the German Technological Corporation, a development think tank.

While NGOs can usually get aid to communities the quickest, governments offer their own advantages, Levine said. “Government ministries can be heavy, and take a long time to work,” Levine said. “But they offer a large-scale distribution basis that is difficult to replicate with NGOs.”

This new filter technology would be best used as a stop-gap in areas where there is no pre-existing infrastructure for purifying water, Levine said. “In the long term, the question is how to stabilise the water supply,” Levine said. “In the meantime, you need technologies like this.”

Some areas, such as the city of Juba in southern Sudan, rely on international donors for their clean water, explained Stephen Maxwell Kwame Donkor, chair of United Nations Water/Africa. While these donors may save lives, Donkor said their contribution is ultimately unsustainable, as the communities they serve are not self-reliant for their basic needs.

“In Juba, for example, (water treatment methods are) highly subsidised to save lives through cholera prevention,” Donkor said.

Filters are best used in emergency situations, Donkor said. But he added they are not meant to be primary sources of water. “Emergency measures are stop gaps before more permanent infrastructure is in place such as wells, boreholes, and treatment plants,” Donkor said.

In situations like the ongoing flooding in Pakistan, water filters can present their own pitfalls, according to John Kings, Managing Director of Tsogang Water and Sanitation. Filters can, for example, become clogged and present a health hazard, or be rendered ineffective by improper use, Kings said.

In terms of cost, the ‘tea bag’ filter is cheaper than both bottled water and other water filtration devices, which can cost from 20 dollars upwards, Cloete said. Raw materials for the filter cost between three and ten cents per litre, though Cloete said he is unsure how much the finished product will cost.

Cloete said he hopes to begin production of the filters by the end of 2010.