Leaching of Arsenic from Wastes of Arsenic Removal Systems

Contamination of groundwater with arsenic is considered as a major challenge in the water supply sector of Bangladesh. ITN-BUET has conducted a number of researches on arsenic issue. In continuation of ITN-BUET initiatives, a research on “Leaching of Arsenic from Wastes of Arsenic Removal Systems” was conducted by ITN-BUET during 2001 to 2002. This publication is the outcome of this initiative.

Almost all the materials used for filtration in the process of removing arsenic, get clogged after prolonged use. Some of these units may be regenerated by washing with water or other reagents. However, after certain time the filter column has to be discarded. These spent filter media are likely to contain very high level of arsenic following continuous accumulation. Also, some of the arsenic removal units generate liquid sludge containing high level of arsenic associated with iron flocs. Indiscriminate disposal of these spent media or sludge is likely to contaminate the surface water sources or may leach arsenic, which may be transported to the underlying aquifer. This study focused on determining the leachable arsenic from adsorbed filter media and sludge under anaerobic conditions created by decomposing organic wastes.