Features
The Sticky Side of Water, Waste-Water Treatment
Microbiologists aim to improve water treatment by better understanding bacteria
BY ARTHUR CHURCHYARD
SPARK PROGRAM
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| Graduate students Bailey Davis and Patrick Soo are working with Prof. Steven Liss to keep municipal water safe and pure. Photo by Martin Schwalbe |
Water and waste-water treatment systems could be improved with a better under- standing of how bacteria behave, says a U of G microbiologist. Little is known about the physical-chemical interactions of bacteria in these systems, such as how they stick to each other and other surfaces, says Prof. Steven Liss, associate vice-president (research services) and a faculty member in the Department of Environmental Biology.
He is working closely with engineers and waste-water treatment plant operators to develop new ways of advancing technologies, developing better water disinfection strategies and improving water sampling methods that detect harmful pathogens.
Liss is leading a team of microbiologists exploring the interface between microbes and engineered environmental systems. Their goal is to equip engineers and operators with more effective techniques for removing water-borne pathogens.
“Collaborating across disciplines is extremely important in my research,” he says.
“By collaborating, we build tools in the laboratory that can be transferred to systems designed by engineers and operated by the water treatment industry.”
Liss co-ordinates multiple projects that investigate the ways microbes behave in water and waste-water treatment systems.
For example, he and his collaborators at the University of Toronto are using a new technology called the membrane-aerated bioreactor (MABR). It is submerged in waste water and uses biofilms that develop when bacteria exude sticky molecules that allow them to form a film on surfaces such as filtering membranes. The MABR can support a biofilm on its membrane, which is fed with oxygen gas to support the biofilm. This process uses less energy than current technologies and can operate at higher capacities.
But undesirable biofilms can form and bind too tightly to a submerged MABR’s membrane, a process called biofouling. When that happens, membrane permeability decreases, making the treatment system inefficient. Liss is investigating the mechanisms behind biofouling to contribute to better control strategies and system design.
Collaborating with industry partners such as GE-Zenon Environmental Inc., he is also using his microbiology expertise in applications such as improved industrial pulp and paper emissions processing and well-water sustainability in rural Ontario.
On the horizon, Liss sees his research progressing through continued studies of microbial flocculation and film structures that advance innovations in technology and improve the understanding of important environmental processes. This work is taking several key directions, including:
- minimizing environmental impacts of industrial emissions;
- further developing membrane bioreactors that would require less energy;
- better characterization of fixed film-activated sludge systems that use both suspended growth forms and fixed biofilms to treat waste;
- developing biorefining strategies for more effective waste-water treatment options; and
- studying the fate of pathogens in natural and engineered systems.
Liss’s work will be supported by research associate Mahendran Basuvaraj, PhD candidate Sandra Tirado and master’s students Patrick Soo and Bailey Davis.
Tirado is focused on pathogens’ transport, survival and ultimate fate in water systems. Soo is quantifying microbial risk in water systems to determine the exact consequences of different levels of tiny microbes called protozoans. Davis is studying enteric viruses in source water.
Funding for this research is provided by the Canadian Water Network; Agriculture and Agri-Food Canada through the Agricultural Bioproducts Innovation Program; the Ontario Ministry of Agriculture, Food and Rural Affairs; Environment Canada through the Best of Science program; the Ontario Centres of Excellence; and the Natural Sciences and Engineering Research Council.
Editor’s note: This article is the cover story in the spring issue of Research magazine, produced by the Office of Research and written and co-ordinated by students involved in the University’s SPARK (Students Promoting Awareness of Research Knowledge) program. The publication can be viewed online at www.uoguelph.ca/research/publications.