A Tanzanian chemical engineer’s sand-based water filter that cleans contaminated drinking water using nanotechnology has won the Royal Academy of Engineering’s first Africa Prize for Engineering Innovation.
The specialised water-filtration system, created by Dr Askwar Hilonga is assembled depending on the needs identified in a specific area: for example, if local groundwater contains arsenic then the filter’s nanomaterials are modified to specifically target arsenic, while at the same time removing bacteria and other biological contaminants.
Everything from heavy metals or minerals such as copper and fluoride, to biological contaminants like bacteria and viruses, and pollutants such as pesticides can be removed by using various combinations of tailored nano materials.
‘Our water filter is a complete water purification system designed by integrating nanomaterials into the slow-sand water filters,’ said Dr Hilonga. ‘It contains a slow-sand-filter for removal of water turbidity, and up to 97% removal of micro-organisms such as bacteria, viruses, and protozoa. There is also a nanofilter – a trademarked innovation – for removal of harmful chemicals and complete disinfection without the need of further treatment with chemicals or UV.’
It also contains a 0.1 micron hollow fibre membrane for quality assurance, will provide up to 60 L (3 buckets) of 99.999% clean and safe drinking water daily, and is set for commercialisation within a year. The filter’s working life should be not less than 5 years, though the nanomaterials need to be replaced after every 800 litres of water, depending on the local level of contaminants.
Although it will cost around USD $130, Dr Hilonga plans to develop ‘Water Stations’ run by local entrepreneurs who will sell water five times cheaper than commercial bottled water.