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ON-SITE APPLICABILITY OF HYDROGEN PEROXIDE PRODUCING MICROBIAL ELECTROCHEMICAL CELLS COUPLED WITH UV IN WASTEWATER DISINFECTION STUDY
Citation:
Ryu, H., L. Boczek, J. Hoelle, AND M. Rodgers. ON-SITE APPLICABILITY OF HYDROGEN PEROXIDE PRODUCING MICROBIAL ELECTROCHEMICAL CELLS COUPLED WITH UV IN WASTEWATER DISINFECTION STUDY. Presented at American Society for Microbiology General Meeting, New Orleans, LA, May 30 - June 03, 2015.
Impact/Purpose:
Reports important data on the use of natural microbial communities found in wastewaters to produce hydrogen peroxide disinfectant and the coupling of this disinfectant generation with ultraviolet light to inactivate human pathogens.
Description:
There is an increased interest in the application of microbial electrochemical cell (MEC) for the recovery of value-added products such as hydrogen gas and hydrogen peroxide (H2O2) from wastewater. H2O2 has strong oxidation capability and produces hydroxyl radicals when coupled with UV irradiation. An advance oxidation process (AOP) with H2O2 /UV has been shown to be effective in removing/inactivating both chemical and microbial contaminants. In this study, we attempted to evaluate the performance of a H2O2 producing MEC and to demonstrate its on-site utilization coupled with UV in microbial inactivation experiments. : A laboratory-scale MEC was operated in a continuous feed mode with synthetic wastewater (i.e., acetate media) and municipal wastewater. Water samples were collected from the cathode and anode compartments on an hourly basis for 6 hr and at 24 hr and analyzed for H2O2 and chemical oxygen demand (COD). Anode potential and cell voltage were recorded every minute. Coulombic and H2O2 conversion efficiencies were calculated using consumption of COD and production rate of H2O2. A bench-scale AOP with H2O2 /low-pressure UV at 254 nm was performed against human adenovirus. H2O2 concentrations from MEC with synthetic wastewater increased gradually as time passed, resulting in the final concentration of about 40 mM (~1400 mg/L) in 70 mL for 24 hr. H2O2 conversion efficiency during the first 6 hr averaged to 44% but decreased to 24% at 24 hr. The exact mechanisms of this significant reduction in cathode performance for converting electrons to H2O2 formation is still not clear. Compared to either UV or H2O2 treatments alone, UV can couple synergistically with H2O2 to sufficiently inactivate UV-resistant human adenovirus. Combining MEC with AOP holds promise for meeting the challenge of the net-zero concept of wastewater treatment and we have demonstrated its on-site application.
