Arsenic removal from groundwater by small-scale reverse osmosis unit in rural Bihar, India

Arsenic contamination of groundwater poses a serious threat to the population in low-lying Gangetic plain of Bihar where arsenic in groundwater occurs in a wide range from Below Detection Limit (BDL) up to more than 600 mu g/L. Pilot-scale trials on arsenic removal were conducted at two locations employing an energy efficient small-scale Reverse Osmosis (RO) unit with upstream Granular Media Filters (GMFs) in order to remove precipitated iron(hydr) oxide. The trials showed that the major part of arsenic can be removed through co-precipitation and subsequent GMF, however, the arsenic level in most cases cannot comply with the Indian National Standard of 10 mu g/L. Only subsequent treatment by RO will ensure safe values below the stipulated limit.