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Of all the naturally occurring groundwater contaminants, arsenic is by far the most toxic. Any large-scale treatment strategy to remove arsenic from groundwater must take into consideration safe containment of the arsenic removed with no adverse ecological impact. Currently, 175 well-head community-based arsenic removal units are in operation in remote villages of the Indian subcontinent. Approximately 150,000 villagers collect arsenic-safe potable water everyday from these units. The continued safe operation of these units has amply demonstrated that use of regenerable arsenic-selective adsorbents is quite viable in remote locations. Upon exhaustion, the adsorbents are regenerated in a central facility by a few trained villagers and reused. The process of regeneration reduces the volume of disposable arsenic-laden solids by nearly 2 orders of magnitude. Finally, the arsenic-laden solids are contained on well-aerated coarse-sand filters with minimum arsenic leaching. This disposal technique is scientifically more appropriate than dumping arsenic-loaded adsorbents in the reducing environment of landfills as currently practiced in developed countries including the United States.

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