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Collaborative study will investigate membrane systems in waste-water treatment and reuse
BY ANDREW VOWLES
A U of G environmental engineer will lead a new cross-country research group studying emerging technology intended to protect water resources and ensure safe drinking water for people in Canada and abroad.
The collaborative study to be led by Prof. Hongde Zhou, Engineering, will involve five universities and industry partners in investigations of membrane bioreactor processes for waste-water treatment and reuse.
This winter, the Canadian Water Network (CWN) approved a two-year $400,000 grant for the group. Along with funding from the Ontario Centres of Excellence — the Centre for Earth and Environmental Technologies (formerly CRESTech) — and from private sources, the researchers will receive a total of almost $1.25 million.
The funding will enable them to study and improve membrane technology for removing contaminants from waste water. Zhou says membrane bioreactors are still a largely untapped form of waste-water treatment that will be needed to prevent new kinds of organic and microbial contaminants from poisoning our water supply.
Add in rapidly expanding populations whose increased consumption has prompted calls for water reuse and increasingly strict regulatory requirements, and there's an emerging market for more advanced water-treatment systems, he says.
“People want better water to protect health and the environment.”
Water-borne pathogens can pose significant health threats in developed countries, such as the tainted water that killed seven people and sickened thousands in Walkerton, Ont. In developing nations, poor-quality drinking water continues to cause many infectious diseases, the single largest source of human mortality, according to the World Health Organization.
Zhou and engineering professor Khosrow Farahbakhsh will team up with researchers at the universities of British Columbia and Manitoba, Ryerson University and École Polytechnique de Montréal, as well as industry and municipal partners.
Membrane bioreactors use arrays of polymer membranes to filter contaminants from waste water. Only about 5,000 systems have been installed worldwide, a relative handful among the conventional activated sludge treatment systems operating in municipalities around the world. Rather than replace those conventional aeration systems, membrane bioreactors are combined with existing treatment processes to ensure removal of particulate and dissolved contaminants, from resistant pathogens to new kinds of endocrine disrupter chemicals.
Previous research with Zenon Environmental Inc. of Oakville and the City of Guelph waste-water treatment plant shows promise to reduce the aeration costs for membrane waste-water treatment systems by 30 to 40 per cent, says Zhou. “That's millions in savings, given the volumes of waste water to be treated by municipalities.”
He notes that costs of the technology have become competitive with those of existing systems, particularly for plants handling less than 15 million gallons of waste water a day.
As the world's largest producer of these membrane systems, Zenon has seen annual growth of 25 per cent over the last five years. “Membrane technology is key for future waste-water treatment,” says Zhou.
He will study ways to prevent the fouling of membranes caused by contaminants adhering to the polymer material. He and his students have worked on a pilot study with the City of Guelph. He now plans to scale up the study at the city's waste-water treatment plant.
“The city wants to see if membrane bioreactors can increase treatment capacity and provide better treatment,” he says, referring to a long-term waste-water resource management plan under development.
Farahbakhsh will lead a study at the Guelph treatment plant on using membranes for tertiary treatment of waste water. Referring to attempts to reduce phosphorus from effluent, which promotes growth of algae in rivers and lakes, he says: “We believe that using a combination of chemical treatment and membrane filtration will not only provide good phosphorus removal but would also significantly reduce costs of chemical use and production of sludge.”
He says the entire project will make U of G a national leader in studying and applying membrane technology in waste-water treatment and reuse.
Closer to home, “what we are doing through this project will definitely help to advance certain technologies that could significantly improve the quality of waste-water effluent discharge into the Speed River,” says Farahbakhsh. “That has a huge impact on the entire community of Guelph.”
In addition, group researchers will examine bioreactor design to remove nitrogen and phosphorus from waste water more efficiently. Zhou expects the project will lead to more waste-water reuse, reduce sludge production and yield new computer models for designing and running membrane bioreactor systems.
He has studied membrane technology in water and waste-water treatment since arriving at Guelph in 1999. The School of Engineering is home to programs in environmental engineering and water resources engineering, and has long-standing research ties with the City of Guelph.
Funded through the federal Networks of Centres of Excellence program, the Canadian Water Network based in Waterloo supports multidisciplinary projects on critical water issues.
