While in the developed world getting access to clean drinking water requires nothing more than turning on the tap, the conditions in some parts of the world are just the opposite, where people, especially women, have to walk miles just to get to the nearest source of freshwater. Moreover, even after sourcing freshwater from miles away, there is no guarantee that it’s drinkable. To solve the problems a team of researchers at University of Virginia have come up with PureMadi filters and MadiDrops.
While made using similar materials, both the filters are different in their operating principles. The PureMadi filters resemble flower pots and are used to both mechanically remove particulate matter from water and also kill harmful microbes within it. The filters, which are locally produced in villages, start with a mixture of clay, sawdust and water. The mix is pressed into a mold and then fired in a kiln.
The firing process burns the sawdust and leaves behind minute holes that allow water molecules to pass through but trap most particles. Further, a coating of silver nanoparticles on the surface of the filter kills bacteria and other harmful microbes commonly found in water. The filtration process does take its time, but once all water passes through the filter, a reported 99.9 percent of the pathogens are removed. While trace amounts of nanoparticles pass to the treated water, they are within safety limits.
The other filter, MadiDrops takes the shape of a tablet that can simply be dropped into a bucket of water. The filter’s silver nanoparticles then kill bacteria and other microbes in water. Though the MadiDrops doesn’t remove particulate matter, it is much cheaper to produce and more easy to transport. Gizmag notes that while the MadiDrops will last for about six months, the PureMadi filters will last up to five years.