The Role of Iron-Rich Sylhet Sand in Removing Arsenic from Water

Arsenic in ground water was first detected in Bangladesh at Chapai Nawabgonj district in 1993. In the context of prevalence of high concentrations of arsenic in tube-well water, a wide range of technologies has been developed but most of them have limitations. In the quest, naturally available iron-rich Sylhet sand was selected in this study as filter bed material to observe the effectiveness in removing arsenic from water. Experiment shows that the Sylhet sand contains a significant quantity of iron (29.4 mg/g), which may play a vital role in removing arsenic through adsorption. Laboratory column tests were conducted using synthetic trivalent arsenic concentration of 200 mg/L and maintaining a constant pH of 8.0 and the experiment was performed on three different forms of sand bed such as normal, burnt and extracted sand bed. Observation shows that the normal and burnt sand bed readily able to remove arsenic and bed volume of 255 and 315 are found respectively up to 50 μg/L arsenic level whereas extracted shows zero bed volume. Hence the iron-rich Sylhet sand bed may be a promising option for arsenic removal and proper design will ease the pavement to make the technology more effective.