Removal of arsenic from contaminated groundwater with application of iron electrodissolution, aeration and sand filtration

The results from a new water treatment system for arsenic removal are presented. The technology is based on the employment of an electrolytic iron dissolution and efficient aeration procedure prior to sand filtration. The treatment was introduced and investigated in a pilot scale plant and full scale waterworks. The pilot scale results showed the potential for efficient arsenic removal from spiked solutions (with As in the range of 50–85 μg/L) depending on the process conditions (flow and applied current). In the waterworks where the system was implemented for a period of 14 months, there was a relationship where the higher applied current from the iron generator resulted in a better quality of water produced. The long period of use also helped to determine a proper iron dosage (the Fe/As ratio 68 mg/mg) and identify carbonate scale formation in the electrochemical process. The electrolytic dissolution of the Fe was found to be a practical method for iron dosing; however more work has to be done on process improvement and optimization that will focus on the Fe anode geometry.