WaterTalk: Challenges and opportunities for moving from the linear to the circular water cycle

Thursday, October 20, 2022 11:30 am - 12:30 pm EDT (GMT -04:00)

WaterTalks

As part of the Water Institute's WaterTalks lecture seriesWilliam A. Mitch, Department of Civil and Environmental Engineering, Stanford University, Palo Alto, CA, USA, will present: Challenges and opportunities for moving from the linear to the circular water cycle.

This event will be offered in person on the University of Waterloo campus in DC 1302 from 11:30 a.m. - 12:30 p.m.

More information

As indicated by its name, “wastewater” has traditionally been considered a waste, with the development of safe methods for its disposal to surface waters being the primary focus of research. The increasing frequency of droughts in arid regions has necessitated the identification of novel water sources. Utilities have recognized that wastewater provides a local, reliable supply of water that can be more cost-effective than importing additional pristine water supplies or seawater desalination. In addition to water, utilities are increasingly viewing wastewater as a resource from which nutrients, energy, and even information could be recovered. In place of the “once-through” conventional model of wastewater treatment for disposal to surface waters, utilities are developing a circular model enabling recovery of these vital resources.

A key challenge has been the development of advanced treatment process trains that produce a quality of water of sufficient quality for potable reuse. This presentation summarizes some of the process trains used and the metrics developed to evaluate water quality. Conventional, linear wastewater systems expend significant energy to degrade nutrients prior to disposal to surface water, while significant energy is expended for the industrial production of nutrients for agriculture. This presentation will provide some discussion of efforts to recovery nutrients from wastewater, including how the treatment trains being developed to extract water for potable reuse can facilitate nutrient recovery. The aeration required to deliver the oxygen for aerobic wastewater treatment systems consumes significant amounts of energy. This presentation discusses novel treatment trains that rely on anaerobic bacteria. In addition to avoiding the energy expense associated with aeration, fermentation of the dissolved organics by anaerobic bacteria produces methane that can be harvested for energy production.  The presentation ends with some of the key challenges associated with integrating the different treatment chains associated with these different objectives as well as challenges related to decentralized systems for the resource recovery from wastewater. 

Speaker bio

Mitch
Bill Mitch is a Professor in the Department of Civil and Environmental Engineering at Stanford University.  His research focuses on environmental organic chemistry, with particular interests in contaminant removal within treatment trains for the potable reuse of municipal wastewater, advanced oxidation processes, reactions of disinfectants, and seawater photochemistry. He obtained a BA in Archaeology from Harvard University and MS and PhD degrees in Civil and Environmental Engineering from the University of California at Berkeley.  He received the 2004 Outstanding Doctoral Dissertation Award from the Association of Environmental Engineering and Science Professors and Parsons Engineering, and a NSF Career Award in 2007. He served as the Chair of the 2017 Disinfection Byproducts Gordon Conference. He has served on the EPA’s Scientific Advisory Panel’s Drinking Water Committee. He holds a PE license in California.


The University of Waterloo is committed to achieving barrier-free accessibility for persons with disabilities who are visiting, studying or working at Waterloo. If you have questions concerning access or wish to request accommodations for this event, please contact Julie Grant (j26grant@uwaterloo.ca)