Household Water Treatment Techniques for Chemical Removal Susan Murcott, Senior Lecturer, MIT, Passive Oxidation Solar Oxidation and Removal of Arsenic (SORAS) Asia Arsenic Network Filter Bucket Treatment Unit (BTU) 2-KolshiPuR Magc-Alcan FilterNirmal FilterRead-F Filter Shapla Filter Sono FilterKanchan Arsenic Filter (KAF) Oxidation and coagulation using KMnO4 and alum Followed by filtration through cloth Moderate arsenic removal (~60%) $10 capital cost $15-20 chemical cost/ family/ year Oxidation and coagulation using sodium hypochlorite and ferric chloride Followed by filtration in a ceramic filter Arsenic adsorption on Bangladeshi-made iron-oxide coated brick chips Good arsenic removal (80-90%) Short media lifespan (3-6 months) Arsenic adsorption on Japanese- made, proprietary, hydrous cerium oxide Excellent arsenic removal (95+%) Long media lifespan (3+ years) $50-70 capital cost Arsenic adsorption on American-made activated alumina Two identical buckets of media Good arsenic removal (80-85%) Good fluoride removal Media life span about 1 year $35-50 capital cost If iron > 8ppm, 75-90% arsenic removal If iron < 5ppm, <50% arsenic removal Excellent microbial removal (99+%) Arsenic removal dependent on iron concentration Typically 70-80% arsenic removal Manual aeration and oxidation of natural iron in water Arsenic co-precipitate with ferric hydroxide Followed by sand filtration Aeration bucket Sand filter Arsenic removal dependent on iron concentration Typically 30-50% arsenic removal Minimal cost Leave water overnight in container Arsenic co-precipitation with natural iron in water Surface complexation of arsenic on composite iron matrix; Followed by sand filtration Excellent arsenic removal (90-95+%) $40-50 capital cost Replacement of unit after 3-5 years Oxidation and coagulation using calcium hypochlorite and ferric sulfate Followed by sedimentation and filtration through cloth A regular biosand filter modified with a tray of rusty iron nails for arsenic removal through surface complexation Arsenic adsorption on Indian-made activated alumina; Followed by filtration through ceramic candle Good arsenic removal (80-90%) $10-15 capital cost Regenerate alumina every 6 months New alumina after 3 regenerations Although “the most common and widespread health risk associated with drinking water is microbial contamination” (WHO, 2004), in parts of the world, certain chemicals, including arsenic, fluoride and nitrate, is causing serious health effects from excessive exposure through drinking water. For example, arsenic contamination worldwide affects an estimated 160 million people (WHO, 2008). In Bangladesh, approximately 30 – 40 million people are exposed to arsenic contamination, with an expected 2.5 million people developing some form of arsenicosis symptom in their lifetime and over 320,000 people dying from arsenic induced cancer over the next 50 years (World Bank, 2005). Here we will describe some of the simple and low cost techniques to remove arsenic at the household level. References: WHO. Guidelines for Drinking Water Quality. Vol. 1. 3rd Edition. Geneva, WHO. Arsenic Contamination in the World: An International Sourcebook. Forthcoming Publication World Bank. Towards a More Effective Operational Response – Arsenic Contamination of Groundwater in South and East Asian Countries. Vol. 1. Policy Report. Washington, 2005 $10 capital cost $10-15 media replacement cost/ family/ year Good arsenic removal (90%) Good microbial removal (99%) $10 capital cost $15-20 chemical cost/ family/ year Excellent arsenic removal (80-95%) Good microbial removal (85-99%) $25-30 capital cost Replacement of iron nails after 2-3 years ($5-8) Excellent arsenic removal (95+%) Excellent microbial removal (99+%) $ chemical cost/ family/ year Similar to SODIS, but add lemon juice Photo-chemical oxidation of As(III) to (V), followed by co-precipitation with iron $15-20 capital cost Tommy Ka Kit Ngai, Research Associate, CAWST,