Online

Khan, Kamruzzaman

Civil and Environmental Engineering

2023

Ph. D.

Clean water is one of the most essential substances for life on earth. However, human activities generate wastewater containing nutrients, pathogens, and other pollutants. The wastewater must be treated to specific standards before discharging into a natural body of water. Wastewater treatment is already a challenging task, and it is becoming more challenging due to increased human activities and pollutants of emerging concern. To address these challenges, a unique electric field-assisted method has been developed to complement existing treatment techniques to enhance the efficacy of wastewater treatment. There are two main parts to this work. The first part of the research shows how an oscillating electric field (OEF) can be applied to enhance phosphorus recovery from wastewater as a useful form (Struvite). In this study, an anaerobic digester supernatant, rich in phosphorus and ammonia, is exposed to OEF using a custom-built device. Various parameters-- ncluding pH, dissolved and total phosphorus, and nitrogen--were monitored and analyzed to determine the struvite crystal nucleation and recovery efficiency. A key finding of this research is that 85% of dissolved phosphorus was consistently recovered. The results from bench-scale experiments are then reproduced in a full-scale pilot work at Essex Resource Recovery Facility, Essex, VT. The second part of the research contains the detection and fate of SARS-CoV-2 RNA and Escherichia coli in wastewater in the presence of OEF. It has been found that COVID-19-infected persons' fecal matter contains SARS-CoV-2 that ends up in the wastewater at the treatment facilities. Several studies have shown that it is possible to use the concentration of the virus or its nucleic acids in wastewater to forecast the prevalence of a disease outbreak within a community. SARS-CoV-2 RNA has been widely detected in wastewater during the Covid-19 pandemic. Therefore, it is critical to public health that both viral and bacterial pathogens are disinfected in the treatment facilities prior to the discharge of effluents into nearby water bodies. As an alternative to conventional disinfection strategies, the efficacy of E. coli disinfection in the presence of OEF was evaluated. E. coli was chosen as a model for the bacterial pathogen. The result shows that exposure to OEF resulted in 8-log disinfection without adding chemical disinfectants.