Indian scientists have come up with a new solution to secure safe drinking water for the developing world.
The good news is that it seems to be largely affordable – for just $2.50 a year, the technology promises to provide safe drinking water to families in remote rural areas. The estimated cost includes both, the cost of the device and the operating costs. The research results were published in May’s Proceedings of the National Academy of Sciences.
Although the technique was already known, the scientists had to identify the right material that would be both – effective and affordable. "We had to find a material that was easily available, cheap, environmentally friendly and that maintained a sustained release of silver ions that could keep its concentration in water at less than 50 parts per billion, which is the WHO permissible level for silver [nanoparticles] in water", said Thalappil Pradeep, an author of the paper and a professor in IITM's chemistry department, in an interview with SciDev.Net.
The team chose a nanocomposite material called aluminium oxy-hydroxide-chitosan. According to Pradeep the structure and the diameter of the silver nanoparticles embedded in this material offer optimal conditions for controlling the release of silver ions in temperatures ranging from five to 35 degrees Celsius. The advantage of silver nanoparticles is that they are small enough to easily release ions into the water but large enough to stay confined within the nanocomposite’s structure.
The sanitising nanomaterial is placed in a sieve through which water is passed. When the silver nanoparticles get coated with impurities, the device can be reactivated simply by boiling or washing with lemon juice. Each unit is expected to last around six years.
Currently, the system is being installed in water treatment plants in the Indian state of West Bengal but the team is seeking commercial partners who might help them mass-produce the device for household water filtration. Amitabha Sengupta, a former scientist at the West Bengal State Water Investigation Department, said such a low-cost filter is urgently needed to bring safe drinking water to the poor due to the huge number of deaths from waterborne intestinal diseases in India.
According the World Health Organization (WHO), waterborne diseases are the number one cause of death around the world, killing approximately 3.4 million people each year, with the majority of the victims coming from developing countries.