Electrochemical oxidation for stormwater disinfection: How does real stormwater chemistry impact on pathogen removal and disinfection by-products level?
Wenjun Feng, David T McCarthy, Rebekah Henry, Xiwang Zhang, Kefeng Zhang, Ana Deletic
Author Information
Wenjun Feng: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Monash Infrastructure Research Institute, Department of Civil Engineering, Monash University, VIC, 3800, Australia.
David T McCarthy: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Monash Infrastructure Research Institute, Department of Civil Engineering, Monash University, VIC, 3800, Australia.
Rebekah Henry: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Monash Infrastructure Research Institute, Department of Civil Engineering, Monash University, VIC, 3800, Australia.
Xiwang Zhang: Department of Chemical Engineering, Monash University, VIC, 3800, Australia.
Kefeng Zhang: UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
Ana Deletic: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Monash Infrastructure Research Institute, Department of Civil Engineering, Monash University, VIC, 3800, Australia; UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia. Electronic address: a.deletic@unsw.edu.au.
Preliminary laboratory work has shown that electrochemical oxidation (ECO) is a promising technology for disinfection of harvested stormwater. This paper focuses on understanding how stormwater chemistry (e.g. pH, chloride, bicarbonate, ammonia and total organic carbon - that can vary substantially between sites) impacts the disinfection performance of ECO. Real stormwater samples from four different urban catchments were collected and tested for ECO performance in disinfecting stormwater pathogens using a boron doped diamond anode under the current density of 4.2 mA/cm. Results showed that total disinfection of indigenous Escherichia coli (E. coli), as well as three different stormwater pathogens (Enterococci, Campylobacter and C. perfringens) was achievable for all four tested stormwater within 30 min. Compared to the synthetic stormwater, lower disinfection rates were observed in real stormwater which has more complex chemistry. Stormwater chloride concentration was the only tested parameter that had significant impact on the treatment performance, with higher initial stormwater chloride concentration leading to an increased disinfection rate. Disinfection by-products in the treated stormwater were well below the Australian Drinking Water Guideline value for health, with its production level positively correlated to the pH values of stormwater.
