Access to clean water is an ever-present struggle for over 780 million people on the planet -- so no wonder affordable and effective water purification tools are considered life-savers in such cases. Based out of the University of Virginia, the non-profit organization PureMadi has come up with an easy-to-use water purification system that combines ceramics with copper and silver nanoparticles to clean up to 99.9% of the potentially deadly pathogens found in water.
Bringing together the experience of the university's students and faculty members from various disciplines, PureMadi has been making ceramic water filters of the same name for the past year out of a factory in Limpopo province, South Africa. ScienceDaily details how the filter -- which has been tested extensively at the university -- works:
The filters are made of local clay, sawdust and water. Those materials are mixed and pressed into a mold. The result is a flowerpot-shaped filter, which is then fired in a kiln. The firing burns off the sawdust, leaving a ceramic with very fine pores. The filter is then painted with a thin solution of silver or copper nanoparticles that serve as a highly effective disinfectant for waterborne pathogens, the type of which can cause severe diarrhea, vomiting and dehydration.
The design allows a user to pour water from an untreated source, such as a river or well, into the pot and allow it to filter through into a five-gallon bucket underneath. The pot has a flow rate of one to three liters per hour, enough for drinking and cooking. The filtered water is accessed through a spigot in the bucket.
They've also developed MadiDrop, a water purification tablet made out of the same nanoparticles that can work in conjunction with the flowerpot-shaped ceramic filters or alone. It's a cheaper alternative to the more costly filter, and a single tablet can work up to six months in the same vessel, purifying water that is poured in -- though it doesn't eliminate sediment as the filter would.
There are big plans in store for PureMadi, says project leader James Smith, a civil and environmental engineer at U.Va:
Eventually that factory will be capable of producing about 500 to 1,000 filters per month, and our 10-year plan is to build 10 to 12 factories in South Africa and other countries. Each filter can serve a family of five or six for two to five years, so we plan to eventually serve at least 500,000 people per year with new filters.