Chronic arsenic (As) pollution in aquifers is one of the major challenges faced by economically and socially marginalized sections of the world, which often depend heavily on groundwater for their sustenance. To safeguard these sections against As poisoning, an easy-to-use and sustainable water-treatment solution is warranted. This study was undertaken to systematically evaluate the performance and feasibility of a low-cost modified biosand filter (JalKalp) in providing potable water to affected rural households in India. JalKalp removes As by sorption on rusted-iron nails and pathogens by an additional copper layer. Initially, As-removal efficiencies of this filter were evaluated under laboratory conditions using (1) unpolluted groundwater spiked with variable concentrations (50–500 μg/L) of total dissolved arsenic (As_T), either as As(V), or As(III), or both; and (2) real As-polluted groundwater (∼150 μg/L). Results indicated that the JalKalp filter removed As_T with an efficiency of 95–99% and passed all water quality tests, except hardness and alkalinity. An ∼3-year long “JalKalp” program was then initiated to provide clean drinking water in selected villages of Bihar, India with the support of local agents, nongovernmental and governmental organizations. Filters were installed in select households (n = 22), and the community was involved in the program through training and workshops. The performance of these filters was evaluated through the testing of water and sludge generated, and the conduct of socioeconomic and health surveys. The filter was equally effective under field conditions and removed As_T (<10 μg/L), total iron (<1 mg/L), and fecal coliforms at all locations, at a cost of ∼INR 0.28 (US$ ∼0.004)/L of treated water. JalKalp requires replacement of iron nails after an estimated ∼1.7 years of treatment of ∼6,000 L of water containing 100 μg/L of As_T. Toxicity characteristic leaching procedure on As-containing sludge after filtration indicated that the sludge was not hazardous and could be disposed safely in landfills along with regular municipal waste. Findings from this study could be replicated elsewhere in providing immediate solutions to As-affected water pollution by enabling independent construction and sustainable use of this potentially long-lasting filter.

中文翻译：

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为受地下水中慢性砷污染影响的农村家庭提供饮用水的改良生物砂过滤器

含水层中的慢性砷 (As) 污染是世界上经济和社会边缘化地区面临的主要挑战之一，这些地区通常严重依赖地下水维持生计。为了保护这些部分免受 As 中毒，需要一种易于使用且可持续的水处理解决方案。本研究旨在系统地评估低成本改良生物砂过滤器 (JalKalp) 在为印度受影响的农村家庭提供饮用水方面的性能和可行性。JalKalp 通过额外的铜层吸附在生锈的铁钉和病原体上来去除砷。最初，在实验室条件下使用 (1) 未受污染的地下水中添加了不同浓度 (50–500 μg/L) 的总溶解砷 (As _T)，作为 As(V) 或 As(III)，或两者兼而有之；(2) 实际被砷污染的地下水（~150 μg/L）。结果表明，JalKalp 过滤器以 95-99% 的效率去除 As _T，并通过了除硬度和碱度外的所有水质测试。随后，在当地代理商、非政府组织和政府组织的支持下，启动了一项长达 3 年的“JalKalp”计划，为印度比哈尔邦的选定村庄提供清洁的饮用水。过滤器安装在选定的家庭 ( n = 22)，社区通过培训和研讨会参与了该计划。这些过滤器的性能是通过测试产生的水和污泥以及进行社会经济和健康调查来评估的。该过滤器在现场条件下同样有效，并在所有位置去除 As _T (<10 μg/L)、总铁 (<1 mg/L) 和粪便大肠菌群，成本约为 0.28 印度卢比（约 0.004 美元） /L 处理过的水。JalKalp 需要在处理约 6,000 L 含有 100 μg/L As _T的水约 1.7 年后更换铁钉. 对过滤后含砷污泥的毒性特征浸出程序表明，该污泥无害，可以与普通城市垃圾一起在垃圾填埋场安全处置。这项研究的结果可以在其他地方复制，通过实现这种潜在长效过滤器的独立建造和可持续使用，为受影响的水污染提供即时解决方案。