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Point-of-use water treatment for arsenic removal through iron oxide coated sand : application for the Terai region of Nepal

By 1979- Barika R. (Barika Renee) Poole

Abstract

Arsenic contaminated groundwater is prevalent in a number of countries around the world, most notably West Bengal, Bangladesh and now the Terai region of Nepal. Wide public awareness of the contamination was not until the 1990s, from years to several decades after tubewells were installed to extract groundwater for drinking water. Now, millions of people have arsenic poisoning which causes serious health effects such as arsenicosis, skin and liver cancer, circulatory disorder and hyperpigmentation. For the past three years, the MIT Nepal Water Project has been investigating arsenic contaminated tubewells in Nepal, and has begun to evaluate point-of-use arsenic removal technologies. These technologies must meet certain evaluation criteria: Effective removal of effective removal of total arsenic (As (III) + As (V)), minimally, below the Interim Nepali Standard of 50 [mu]/L; possibility of local manufacture with locally available materials; affordable to the Nepali citizens affected by arsenic contamination; socially acceptable in terms of maintenance, operation and water demand. The 2001-2002 MIT Nepal Project investigated three new technologies which might meet these criteria. Iron oxide coated sand is one of these technologies. Iron oxides are known to adsorb arsenic. Previous studies of arsenic and metal adsorption onto iron oxide coated sand prompted this investigation. Based on the methods utilized in these prior studies, the author produced seven different iron oxide coated sands, varying concentration of ferric nitrate used, coating mixture, and drying temperature. The arsenic removal capability of these sands was tested in Parasi, Nepal, Pepperell, Massachusetts and Salem, New Hampshire. Percent total arsenic removal varied from 11-99%. Considering the evaluation criteria such as arsenic removal performance, cost, availability of materials, and local production, iron oxide coated sand technology successfully meets most or all of these requirements. However, in this study, social acceptability has not been determined. Detailed testing and evaluation of the iron oxide properties, as well as sufficient resources allocated to production of the media, is crucial before iron oxide coated sand technology could be implemented for point-of-use arsenic removal in Nepal or other developing countries. The author also produced a digitized map representing the extent of arsenic contamination in the Terai using paper maps as a base.by Barika R. Poole.Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2002.Includes bibliographical references (leaves 155-159)

Topics: Civil and Environmental Engineering.
Publisher: Massachusetts Institute of Technology
Year: 2002
OAI identifier: oai:dspace.mit.edu:1721.1/8423
Provided by: DSpace@MIT

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