Thu, Sep 16, 2021 @ 11:00 AM - 12:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Speaker: Jiaming Shi, Ph.D. Candidate, Astani Department of Civil and Environmental Engineering
Talk Title: The Fate and Transformation of Nitromethanes during Wastewater Reuse Processes
Abstract: As water resources become increasingly scarce, potable reuse of wastewater is considered to be a potential solution. There are increasingly number of treatment processes currently in used in full- and pilot- scale water reclamation plants involves ozonation. Ozone is considered to be a highly effective oxidant and disinfectant. However, previous research has demonstrated that ozonation of wastewater overall drastically increases chloropicrin formation potential during subsequent chlorination. Nitromethane has been be proven to be the immediate precursor of chloropicrin prior to chlorination, however nitromethane itself is unlikely to be present in wastewater naturally. Previous research indicates that ozone directly oxidizing secondary amines bearing an N-methylamine functional group lead to nitromethane formation.
Ozonation is widely used in wastewater reclamation treatment trains, either for micropollutant control or as a disinfectant and pre-oxidant in certain reuse processes. Nitromethane formation will be strongly promoted post ozonation but its fate through other treatment process remains uncharacterized, which raise the question of can nitromethane be detected in final product water. The objects of this study are to demonstrate that nitromethane formation post ozonation in real full- and pilot scale reuse plants and to characterize the nitromethane fate throughout the entire treatment trains.
In this work, the fate of nitromethane through water reuse treatment trains was characterized by analyzing samples from five reuse operations employing ozone. Nitromethane was poorly (90%) nitromethane. Bench-scale experiments were conducted to verify low removal by RO in clean systems and with wastewater effluent, and to quantify the kinetics of direct and indirect photolysis of nitromethane in UV/AOP.
These results indicate that nitromethane presents a unique hazard to direct potable reuse systems, due to its ubiquitous formation during wastewater ozonation, poor removal by RO and UV/AOP, and facile conversion into genotoxic halonitromethanes upon chlorine addition.
Host: Dr. Daniel McCurry
Webcast: Join Zoom Meeting https://usc.zoom.us/j/99680049945?pwd=V05hVU5xbERjajlUMjFSUHozRUdJQT09 Meeting ID: 996 8004 9945 Passcode: 905716
Contact: Evangeline Reyes