| This study tested the arsenic removal efficiency of a water treatment system, which uses ozone to oxidize iron and arsenic, and then removes the arsenic-iron precipitates by cartridge filtration.; The system was tested on groundwater with 27mug/L arsenic, 0.62mg/L iron and pH 7.9. Operating the system at 550mV ORP reduced arsenic by 33%. Stop/start operations examined the impact of pH and ORP on the removal efficiency, and found reducing the feedwater pH improved removal in all conditions. Maintaining ORP at 550mV and reducing pH to 7.5 produced the best removal efficiency of 77%. These conditions were then applied to feedwater with 18mug/L arsenic and 0.51mg/L iron. The treated water averaged 9mug/L arsenic, a 50% reduction.; The system did not perform as expected, based on efficiencies reported in much of the literature. Several factors may contribute, including impacts of iron-to-arsenic weight ratios, filtration methods, water temperature, and oxidation process. |
