ARSENIC REMOVA,L FROM GROUNDWATER BY OXIDATION-COAGULATION AT CONTROLLED PH FOR DOMESTIC AND COMMUNITY APPLICATIONS

摘要

The present invention is a process for removal of arsenic by oxidation of arsenite to arsenate by an oxidizing agent and subsequent precipitation by coagulation with an iron based coagulant in the presence of a common chemical which maintains optimum pH of the water during the treatment and in the treated water. The method can remove As to much below the maximum contamination level of 0.01 mg/L from an initial concentration up to 0.5 mg/L using only very small quantities of the chemicals. If the water contains dissolved iron then an additional quantity of the oxidant has to be added to the water. The pH of water remains within acceptable range for drinking. The present method is a very low cost method. The method does not add any contaminants to water. Instead, this method lowers the concentration of unwanted heavy metals present in the water. Also, as one of the chemical is a mild disinfectant and as coagulation takes place during the separation, the water is safe from any bacteriological contamination.