Exploratory experiments to determine the effect of alternative operations on the efficiency of subsurface arsenic removal in rural Bangladesh

摘要: The principle of subsurface arsenic (As) removal (SAR) is to extract anoxic groundwater, aerate it and re-inject it. Oxygen in the injected water reacts with iron resident groundwater form hydrous ferric oxide (HFO). Dissolved As sorbs onto HFO, which allows for extraction lower concentrations. SAR was applied at a rural location Bangladesh (As = 200 μg/L) study effect different operational parameters on performance, including repeated injection an equal volume, pumping rate, intermittent pumping. Larger all had positive effects indicating that adsorption kinetically limited. Repeated injection–extraction volume improved efficiency by providing more HFO sorption. After 1,000 L, maximum 3,000 L ‘safe’ water, as defined national standard (<50 μg/L), extracted, 2,000 can be used drinking remainder re-injection. Under this setup, estimated cost As-safe US$2.00, means viable mitigation option areas.