Removal of Arsenic with Oyster Shell: Experimental Measurements

Oyster shell has tremendous potential as a remediation material for the removal of arsenic from groundwater. A single arsenic removal system was developed with oyster shell for tube well water containing arsenic. The system removes arsenic from water by adsorption through fine oyster shell. Various conditions that affect the adsorption/desorption of arsenic were investigated. Adsorption column methods showed the removal of As(III) under the following conditions: initial As concentration, 100 μg /L; oyster shell amount, 6 g; particle size, <355μm ; treatment flow rate, 1.7 mL/min; and pH 6.5. Arsenic concentration of the treated water were below the Bangladesh drinking water standard of 50 μg/L for As. The desorption efficiencies with 2M of KOH after the treatment of groundwater were in the range of 80-83%. A combination of techniques was used to measure the pH, conductivity, cations and anions. The average concentrations of other inorganic constituents of health concern (Na, K, Ca, Mg and Fe) in treated water were below their respective WHO guideline for drinking. The present study might provide new avenues to achieve the arsenic concentrations required for drinking water recommended by Bangladesh and the World Health Organization (WHO).