Environmental Science and Engineering Seminar

Water reuse is a necessity in the new era of increased uncertainty in prolong droughts and sudden heavy rainfall due to the dramatic changes in climate worldwide. Successful recycling of wastewater for human consumption or for vegetable irrigation requires that this water is not contaminated with pathogens, especially human-disease causing viruses. Robust design of virus inactivation for water reuse requires fundamental understanding on virus survival, persistence and transport. My group has conducted comprehensive studies on rotavirus, which is the most common virus that causes severe diarrhea, vomiting and acute dehydration globally. Our results showed that rotavirus is uniquely mobile under conditions related to managed groundwater recharge. In another study, we used a set of rotavirus with known genome sequences to systematically study their susceptibility to solar irradiation. Our approach challenges the conventional approach for water and wastewater disinfection system design, which relies on the use of laboratory data from a model virus or virus surrogates. Our findings showed that the knowledge of the inactivation mechanisms of rotavirus in combination with viral genetics could be used to predict inactivation of rotavirus under conditions relevant to waste stabilization ponds with effluent used for irrigation. Measured data on inactivation of rotavirus adhered to leafy vegetables were also used in a quantitative microbial risk assessment (QMRA) model to estimate the risk of rotavirus infection due to consumption of raw leafy green vegetables. The results showed that the risk of rotavirus infection was the highest with vegetables with low wax crystals disinfected with an oxidant-based sanitizer, while other combinations of vegetables and sanitizers had approximately 100-fold lower risk. Collectively, our comprehensive study on rotavirus contributes to a scientific framework to determine the potential human health impacts of wastewater reused for both human consumption and for irrigation.