Arsenic removal from groundwater using iron electrocoagulation: Effect of charge dosage rate

We demonstrate that electrocoagulation (EC) using iron electrodes can reduce arsenic below 10g/L in synthetic Bangladesh groundwater and in real groundwater from Bangladesh and Cambodia, while investigating the effect of operating parameters that are often overlooked, such as charge dosage rate. We measure arsenic removal performance over a larger range of current density than in any other single previous EC study (5000-fold: 0.02 100mA/cm2) and over a wide range of charge dosage rates (0.060 18 Coulombs/L/min). We find that charge dosage rate has significant effects on both removal capacity (g-As removed/Coulomb) and treatment time and is the appropriate parameter to maintain performance when scaling to different active areas and volumes. We estimate the operating costs of EC treatment in Bangladesh groundwater to be $0.22/m3. Waste sludge (approximate to 80 120mg/L), when tested with the Toxic Characteristic Leachate Protocol (TCLP), is characterized as non-hazardous. Although our focus is on developing a practical device, our results suggest that As[III] is mostly oxidized via a chemical pathway and does not rely on processes occurring at the anode. Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Environmental Science and Health, Part A, to view the free supplemental file.