Arsenic removal from drinking water by manganese greensand

Arsenic could be carcinogenic to humans. The cancer risk associated with the consumption of 1.6 litres of water (containing 50 {dollar}mu{dollar}g/L of total arsenic) has been estimated to be higher than the cancer risks associated with the secondhand smoking and radon in homes. Because of its carcinogenicity potential, many regulating agencies are considering a lower ({dollar}<{dollar}25 {dollar}mu{dollar}g/L) maximum contaminant level (MCL) of arsenic in drinking water. However, the agencies are cautious in lowering the MCL, because of the high cost that may be associated with the water treatment plant's upgrading.; Operating data from iron and arsenic removal plants have suggested that arsenic may be reduced to {dollar}<{dollar}25 {dollar}mu{dollar}g/L by oxidation with KMnO{dollar}sb4{dollar} followed by manganese greensand filtration. Since this water treatment method is typically much cheaper to operate than conventional treatment plants using coagulation, sedimentation, and filtration, it was decided to investigate the arsenic removal capacity of the manganese greensand media.; Batch and column studies were conducted in the Water Research Laboratory at the University of Regina, Canada to investigate the removal of arsenic from solution using oxidation with KMnO{dollar}sb4,{dollar} followed by manganese greensand filtration. Column studies were conducted using tap water. Test results showed that the noted process could reduce the arsenic concentration to {dollar}<{dollar}25 {dollar}mu{dollar}g/L for more than 280 bed volumes. The results also showed that iron played a major role in arsenic removal.