The application of sustainable and energy-efficient water treatment options is the focus of research on water reuse and reclamation. Ferrate (Fe(VI)) is a promising candidate for sustainable water reuse due to its strong oxidation potential and ability to meet multiple treatment objectives including coagulation, contaminant oxidation, and disinfection. Despite the effective disinfection potential of Fe(VI), our fundamental understanding of the interaction between the oxidant and pathogens is still limited. In particular, the presence of trace organic contaminants in effluent wastewater and/or raw water can exert a Fe(VI) demand and impact its disinfection efficacy. We hypothesize that different environmental factors such as water matrix complexity and bacterial growth phases can affect the bacterial susceptibly to Fe(VI). In this work, pure cultures of Escherichia coli were cultivated to different growth phases and exposed to Fe(VI) under different water chemistry conditions (phosphate buffer, minimal media and modified lake water). Fe(VI) concentration of 25 µM achieved approximately 3 log inactivation of late log phase E. coli in phosphate buffer (pH 7). In comparison, the Fe(VI) concentrations needed to achieve 3 log removal of late stationary phase E. coli in minimal media and modified lake water was 68 and 16 times higher, respectively. These results suggest that bacterial susceptibility to Fe(VI) may be influenced by water chemistry. The different bacterial growth phases influence cell physiological processes which could, in turn, affect bacterial susceptibility to Fe(VI). Furthermore, the presence of various water constituents may also contribute to the observed trend. Examining the chemical and physiological factors that play a role in driving the variations in bacterial response will be a highlight of this work. Ultimately, this study aims to examine Fe(VI) disinfection performance more thoroughly and optimize its future use as an oxidant in advanced water treatment processes.

Performance of ferrate as a disinfectant under varying conditions of water reclamation: Physiological and chemical assessments

2019 Fall National Meeting

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