Sulfide precipitation as treatment for iron rich groundwater

摘要

Iron concentrations above the permissible limit of 0.3 mg/L in groundwater makes it unacceptable for drinking. Conventionally, iron removal from groundwater involves aeration and rapid filtration. This paper describes iron removal under anaerobic conditions by batch experiment. The operation involved purging 500 ml of groundwater sample with hydrogen sulfide for about 360 minutes. About 83% removal of iron concentration for 1mg/L of iron solution was attained. For higher initial iron concentrations of 3.55 and 5.01 mg/L, the removal efficiency reduced to 82% and 75%, respectively. At the end of the experiment, the average residual sulfide concentration in groundwater was 25 μg/L, which is lower than 50 μg/L, the standard for drinking and the Eh level was less than -272 mV.