Removal of Microcystins from Drinking Water by Electrocoagulation: Upscaling, Challenges, and Prospects

Abstract

Microcystins (MCs) belong to a family of stable monocyclic heptapeptide compounds responsible for hazardous toxins in drinking water. Although several methods have been applied to remove MCs from drinking water (e.g., activated carbon filtration, ion exchange resins, high-pressure membranes, and electrochemistry), upscaling laboratory experiments to benefit municipal water treatment is still a major challenge. This chapter is a follow-up study designed to test three electrocoagulation (EC) techniques for decomposing MC by UV-ozone purification (laboratory), electrocoagulation (field unit), and coupled UV-ozone-electrocoagulation (municipal treatment). The chemistry and efficiency of the treatments were first examined followed by comparison with activated carbon filtration. Electrocoagulation outperformed activated carbon filtration by nearly 40%. When the laboratory treatments were evaluated at the municipal scale, effectiveness of the technique deteriorated by 10–20% because of UV pulse dissipation, vapor-ion plasma under-functioning, and limitations of polymer fiber filters. We confirmed previously published studies that pollutant coagulation and MC decomposition are affected by physicochemical factors such as radiation pulse density, electrical polarity, pH, and temperature dynamics. The results have relevant applications in wastewater treatment and chemical recycling.