A Comparative Evaluation and Field Implementation of Treatment Technologies for Arsenic Removal from Groundwater

Background of the Arsenic Crisis The groundwater pollution caused by arsenic (please see Box 1) in a number of Asian countries has led to a major environmental crisis. Some recent estimates indicate that more than 35 million people in West Bengal (India), Nepal and Bangladesh are potentially at risk from drinking arsenic-contaminated water (Smith et al., 2000). The crisis has its roots in another worthy effort to fight water-borne diseases that had impacted this tropical region for a long time. Acute health problems, such as gastrointestinal diseases and infant mortality, were attributed to drinking microbiologically-contaminated surface water. It was widely believed that using groundwater would easily circumvent the problem because groundwater at certain depths is not exposed to microbiological contamination. It is now known that the alluvial aquifer that underlies the Ganges-Brahamputra river basin contains arsenic in mineral form. During the past two decades about four million wells have been installed to utilize the groundwater from shallow aquifer layers, typically less than 200m deep (UNICEF, 1999). Exploitation of groundwater from these wells for drinking water and irrigation purposes has resulted in mobilizing the arsenic (Rahman et al., 2001).