Assessment of disinfection and by-product formation during electrochemical treatment of surface water using a Ti/IrO2 anode

Laboratory batch experiments were performed at room temperature to evaluate the electrochemical disinfection of surface water using Ti/IrO2 anodes. Disinfection was assessed as a function of applied current density (0-8 mA/cm(2)) and specific charge Q (A-min/L), and active chlorine generation was measured. Generation of disinfection by-products, including haloacetic acids (HAM), total trihalomethanes (TTHMs), and perchlorate, also was monitored. Results showed that the disinfection rate corresponded to the applied current density. With respect to the applied Q the highest current density (8 mA/cm2) showed the greatest rate of disinfection and highest rate of active chlorine generation. While no perchlorate generation was observed, HAAs and TTHMs were generated at a rate of 7.7 and 5.6 mu g A(-1) min(-1), respectively. However, regulatory exceedances were not observed until greater than a 5-log decrease in bacteria was observed. HAA and TTHM formation, as well as energy consumption, associated with the highest current density were greater than the lower current densities for a given level of disinfection. Overall, this study demonstrates that effective disinfection without regulatory exceedances in TTHMs, HAAs, or perchlorate can be attained using a Ti/IrO2 anode for treatment of surface water. (C) 2014 Elsevier B.V. All rights reserved.