Nanotechnology to change the world

Microbiologist and inventor of the ‘tea bag’ water filter Professor Eugene Cloete

Microbiologist and inventor of the ‘tea bag’ water filter Professor Eugene Cloete

When it comes to pioneering water nanotechnology applications, Professor Eugene Cloete has it, quite literally, in the bag. Not only has his patented “tea bag” water purification filter been termed one of 10 world-changing ideas by the Scientific American journal in 2010, but it has the potential to transform the way over 300 million people on the African continent consume previously contaminated water.

“The reality is that many individuals in rural areas do not have access to ‘potable’ or clean filtered water,” explains Cloete. “The ability to drink and use clean water is a critical human need; one that needs immediate intervention to save the lives of millions. We identified the need for a simple device that can be used to purify and clean highly polluted water at the point of use — a filter that is portable, easy-to-use, environmentally friendly, and so inexpensive that it provides an affordable way for the underprivileged to access clean drinking water.”

The “tea bag” water filter uses nanofibres to suck contaminants and bacteria out of water. To use the device, a person simply places the bag in the neck of a water bottle in order to filter and clean the water as it is consumed. A single bag can filter up to a litre of even the most heavily polluted water, and can be easily disposed of after each use.

According to Cloete, the water filter sachets are made from biodegradable materials identical to off-the-shelf rooibos tea bags. Two tiny “destroyers of all things unsafe” are inside each sachet — ultra-thin nanoscale fibres, which filter harmful contaminants, and bacteria-killing grains of carbon.

The device isn’t quite ready for mass production, but tests of the filter on nearby rivers have been successful. Clean water experts say this filter, which is applied just before people drink, is preferable to systems that clean water before it’s distributed, because it eliminates the risk of recontamination.

Cloete is no stranger to ground-breaking patented processes, including a real-time biofilm monitor, a passive treatment system for treating acid mine drainage, and a biological contact reactor for treating wine cellar effluent. He has also pioneered the use of solar pasteurisation as a method for disinfecting harvested rainwater.

“From an early age when growing up on a dairy farm in Lady Grey, my father drummed it into us that people cannot survive without water and food,” continues Cloete. “It is this mindset, coupled with my desire to live a significant life, that launched my research career in water. Once you shift your focus from achieving goals on a personal level to that of assisting others to achieve their goals, you will have reached significance.”

Looking ahead, Cloete maintains that his future research will continue to focus on innovative solutions to South Africa’s water challenges. “My vision is to develop water treatment systems that will allow for the provision of affordable potable water and wastewater treatment for reuse at the household level.

“We live in a country that offers favourable circumstances for many innovative ideas to develop, part of which is due to its diversity. Exposing ourselves to people from different cultures and different ways of understanding life brings about new ideas, views and inventions that ultimately enrich our existence.”