Electrochemistry offers an innovative method to induce coagulation and oxidation processes for water treatment applications. Conventional coagulation and oxidation are well suited for many drinking water operations to meet regulatory requirements for safe drinking water. However, these processes require many chemicals and materials that must be transported from off-site, which increases the complexity of operations, and can pose a difficulty for small treatment systems or those in remote locations. Electrocoagulation together with electrooxidation can be an attractive option for drinking water treatment systems as these processes can generate chemicals such as iron coagulant, free chlorine, and reactive oxygen species in situ. This treatment approach avoids the need for off-site chemical generation and transportation to the facility, thereby improving accessibility to clean drinking water for small communities or remote locations.  This research focused on the removal of the trace organic compounds trimethoprim (an antibiotic), acyclovir (an antiviral), and BAC-C10 (an antimicrobial) using electrochemical drinking water treatment methods. Iron-electrocoagulation was used to remove large organics and potential hydroxyl radical scavengers as a pretreatment step ahead of electrooxidation. Electrooxidation was performed using a boron doped diamond anode to generate hydroxyl radicals and encourage advanced oxidation. Additional electrooxidation tests were performed using a Ti/IrO<sub>2</sub> anode to promote the generation of free chlorine.  It was hypothesized that electrocoagulation would serve as an effective pretreatment step by removing turbidity and dissolved organic carbon, thereby improving downstream conditions for effective electrooxidation of the trace organic compounds. Electrocoagulation and electrooxidation experiments were conducted in batch conditions in 6 water matrices (2 synthetic surface waters, 2 synthetic groundwaters, and 2 real water sources) with varying conductivity (260 - 760μS/cm) and varying background electrolyte concentrations. Electrocoagulation removed dissolved organic carbon beyond limits set by the Disinfectants and Disinfection Byproducts Rule. In addition, greater than 50% removal was observed for trimethoprim, acyclovir, and BAC-10 using electrooxidation. Following single process experiments, combined process experiments were conducted to assess the synergy of these processes in enhancing total removal of trace organic contaminants.

Electrochemical coagulation and advanced oxidation processes for removing trace organic compounds

256th National Meeting (2018)

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