Bi-tech wells: an effective arsenic mitigation method

Abstract

With more than 150 million people in India, Bangladesh and Nepal exposed to arsenic through drinking water, arsenic mitigation projects are common in the region, including many failed and abandoned projects. Our nonprofit organization, Project Well, has been working since 2001 to provide cheap, easily adaptable safe-water solutions suitable for the local socioeconomic environment. After years of research and experimentation, Project Well has developed a ‘bi-tech’ well that fulfills these criteria by tapping arsenic-safe surface water from unconfined aquifers. From 2001 to 2009, Project Well constructed dugwells modified from local traditional dugwells; one important modification was that water was extracted using hand pumps rather than rope-and-bucket, to minimize bacterial contamination. A sizeable percentage of these dugwells were dry during the summer seasons, so in 2009 we began constructing ‘bi-tech’ wells that combined the features of our bacterial-growth-preventing dugwells with the depth of borewells (8 meters). In the summer of 2014, 94% of bi-tech wells contained water compared to 53% of our modified dugwells. Fecal coliform and E. coli were undetected in tests conducted in 2011 and 2014. In 2015, arsenic concentrations were <10 ppb in 95% of the wells. Bi-tech well maintenance is simple, with dredging rarely necessary, and easy for communities to learn. With its low construction costs, easy maintenance, and consistent safe-water output, bi-tech wells are proving an effective water solution in parts of rural India where piped water is not available.