Bench-Scale Study of Electrochemical Oxidation for On-Site Treatment of Polluted Groundwater

Electrochemical oxidation has been studied in a series of bench-scale tests as a physico-chemical oxidation technique for on-site treatment of very complex polluted groundwater containing pharmaceuticals, chlorinated solvents, volatile organic compounds present in petroleum derivatives, and inorganic salts. Two different cells were applied, one with Ti/Pt-90-Ir-10 and the other with Si/boron-doped diamond anode material, representing two different classes of anode materials for organic oxidation. Chemical oxygen demand and total organic carbon analysis were used to assess performance, and the influence of changing recirculation flow and applied current density was studied. Si/boron-doped diamond exhibited the highest instantaneous current efficiency of 0.17 at 50 mAcm(-2), but further optimization at lower currents closer to the limiting values are needed for the process to be economically attractive. Si/ boron-doped diamond exhibited a superior total organic carbon removal, resulting in full mineralization of the organic groundwater contaminants, relative to the higher degree of partial oxidation obtained by Ti/Pt-90-Ir-10. Model consideration demonstrated the importance of bulk oxidation by generated oxidants using the Ti/Pt-90-Ir-10 anode, in addition to the high dependence of this process on the flow conditions and applied current. DOI: 10.1061/(ASCE)EE.1943-7870.0000561. (C) 2012 American Society of Civil Engineers.