Developing a Low-Cost Water Filter
Editors Note: This week we’ve asked members of P3 teams to share information about the sustainable design projects they’ve been working on to showcase at this year’s National Sustainable Design Expo.
In August of 2009, our P3team traveled to the Pine Ridge Reservation in South Dakota, home of the Oglala Lakota Tribe and some 28,000 people. The purpose of our trip was to sample water to see if it still reflected conditions reflected in U. S. Geological Survey (USGS) report from the 1990s that found much of the reservation’s groundwater was contaminated with arsenic and uranium. Levels of the two contaminants at that time were found to exceed EPA’s maximum containment limits (MCLs).
What we found was in line with the USGS report: 35% of the private wells we tested contained arsenic above the MCL; 6% contained elevated uranium levels. That’s where our P3 project comes in. We are developing a low cost filter that can remove both arsenic and uranium from water.
While there are existing filters that can do the work, they are far from ideal in places like Pine Ridge. For one thing, current filters—primarily based on reverse osmosis (RO) technology—are very expensive. In addition, they require constant maintenance and upkeep.
Our solution looks to provide a cost effective alternative that requires minimal maintenance, can be maintained by local residents, and can spark prosperity in the community. To accomplish this, we’ve developed a filter that uses bone char as its main ingredient.
Cattle bone that is used to make the char is readily available as a waste product on the reservation, and our tests show that our filter effectively removes the contaminants. After performing a life cycle analysis, we predict that after 10 years of use, the bone char filter will outperform a standard RO filter in eight out of nine environmental categories.
The only downside so far is that our current prototype is very large. So, we are now working to reduce the size, which will cut the cost of the filter as well.
While we are working on improving our filter, efforts are underway to inform the Pine Ridge community about the issue of water contamination, and to develop an educational program in partnership with the Oglala Lakota College (OLC) to further understanding of the need for clean drinking water on the reservation.
About the Author: Brett Llewellyn, a student at the University of Illinois, Urbana-Champaign, is working to obtain a Bachelor of Science in Chemical Engineering. He wishes to continue applying his coursework towards the efforts of making water clean and accessible to everyone.
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