Removal system of arsenic from geothermal water by high gradient magnetic separation-HGMS reciprocal filter

We have developed a high gradient magnetic separation (HGMS) system to remove arsenic from geothermal water and to supply hot water for public use by using a superconducting magnet. We attained the reduction of arsenic concentration to 0.015 mg/L that is less than the standard for discharge of 0.1 mg/L and slightly larger than the environmental standard of 0.01 mg/L in Japan. The system consists of a pretreatment process that adds extra magnetization to arsenic by chemical reaction, and a reciprocal HGMS filter using a superconducting magnet that extracts magnetized arsenic from the geothermal water. We present the experimental results of the removal system.