IES Seminar Abstract:
Energy demands to treat municipal wastewater can represent up to 2% of U.S. electricity consumption, and 40 to 60% of this demand is required for aeration to biologically oxidize organic waste and nitrify urea-sourced ammonia. This energy consumption is ironic, given that organics in domestic wastewater have the potential to favorably deliver more than 5 billion amps of current, and that 50 million GJ/yr of energy are used each year to produce the equivalent amount of ammonia via the Haber-Bosch process. In this talk, I will explore opportunities to transform wastewater treatment plants into energy factories, where electrochemical methods are used to direct electrons in wastewater toward synthesis of value-added products, and advanced separation methods are used to recovery ammonia as a commodity fertilizer.

CEE Seminar Abstract:
Per and poly-fluoroalkyl substances (PFAS) are extraordinarily stable and widely used chemicals used to create many consumer and industrial products, including non-stick cookware, water-resistant textile coatings, food packaging, cosmetics, semi-conductors, and aqueous film-forming foams (AFFFs). Due to their widespread use, PFAS have been released to the environment and have contaminated at least 9,500 different sites in the United States. This is a concern because even at very low concentrations PFAS ingestion has been correlated to negative health impacts, including delayed developmental, immune system suppression, and cancer. Efforts to clean up PFAS in groundwater have mainly relied on ex situ approaches, where contaminated groundwater is pumped it to the ground surface and treated in engineered reactors using energy intensive thermal, (electro)chemical, ultrasonic, or plasma-based technologies. An emerging in situ approach is to create barriers to PFAS migration in contaminated aquifers from sorbent materials, e.g., by injecting colloidal activated carbon (CAC) through wells into contaminated aquifers, where it becomes immobilized. However, there remains great uncertainty in how long these sorptive barriers will prevent PFAS migration, and if sorptive barrier amendments can be engineered to promote PFAS degradation. In this talk, I will present experimental and modeling results that address mechanisms controlling PFAS migration in CAC barriers, CAC barrier effectiveness and lifetimes, and an abiotic reaction pathway that complements CAC barriers by promoting in situ PFAS destruction.

Biography:
Dr. Charles Werth is a Professor and the Bettie Margaret Smith Chair in Environmental Health Engineering in the Maseeh Department of Civil, Architectural and Environmental Engineering at the University of Texas at Austin. Dr. Werth’s research and teaching background includes fundamental and applied studies on pollutant fate and treatment in both natural and engineered water systems, with applications in electro(catalytic) drinking water treatment, in situ groundwater remediation, and subsurface storage of carbon dioxide and hydrogen. Dr. Werth received his B.S. in Mechanical Engineering from Texas A&M University, and M.S. and Ph.D. in Civil and Environmental Engineering from Stanford University.