Keeping our water safe

Posted on January 20, 2016

New test equipment in the Coastal Lab to help understand biofilm in pipe systems

Yves Filion

A UNIQUE FACILITY: Engineering professor Yves Filion is ready to recruit graduate students to help conduct water quality experiments at the university's new drinking-water discolouration laboratory facility.

Kingston, Ontario, is a medium-sized city with a medium-sized municipal drinking-water supply system. Drawing mostly from Lake Ontario, the system serves some 37,000 homes and businesses and includes 560 kilometres of water mains, more than 5,000 control valves, 11 storage facilities and 5 booster stations. It’s a safe system—it has to be—but that’s a lot of pipe. It’s a huge and ongoing job to make sure it’s all clean and safe for potable water. 

Material from the treatment process and corrosion products from the distribution pipe network can accumulate on the pipe walls. Hydraulic disturbances can detach this material and leave it suspended in the bulk water, changing its colour and smell, depleting residual disinfectant levels and jeopardizing the quality of our drinking water.

Queen’s researchers are developing a facility that will help them better understand how biofilms form and behave inside pipes so engineers can design and maintain systems that deliver safe and reliable drinking water. The new drinking-water discolouration facility at the Coastal Engineering Lab is an environmental chamber roughly the size of a transport trailer. It houses two pressurized pipeline rigs as well as pumps that draw water from two large tanks supplied by the Kingston water-distribution system. Water pressure and flow inside the pipes can be adjusted, and water temperatures of the whole system can be controlled depending on the experiment.

“We’ll be looking at how the hydraulics near the pipe wall affect the growth of the biofilm,” says Queen’s Civil Engineering Professor Dr. Yves Filion. “Secondly, we’ll be looking at how the biofilm affects chlorine residuals. That’s really what municipalities care about: they want to protect people from pathogens.”

Filion is the principal investigator on the project, which was made possible by a Canada Foundation for Innovation Fund grant. There is a similar facility in the UK, but it uses polyethylene pipe, more common in Europe. North American builders usually use the sort of PVC pipe at the heart of Filion’s rig. That makes it unique in the world.

Filion says that accumulated biofilm can be flushed out of the pipe loop, the water quality analyzed and residual chlorine levels assessed. A series of coupons—little ports along the pipes—can be opened to check the microbiological quality of the biofilm.

“One of the things we want to examine is how drinking-water quality and the hydraulics of the network affect the way biofilm grows on the pipe wall and is mobilized into the bulk water of the pipe,” he says.

His research will help municipalities optimize their flushing operations and prioritize their water-main rehabilitation programs. “My suspicion is that utilities may be using flows that are much, much too high to flush material out of their systems. If you waste water needlessly by over-flushing, you’re losing money.” 

An internationally recognized expert in sustainable water-distribution systems, Filion hopes to help municipalities make better decisions about how they operate and rehabilitate their systems. “This is a new research direction for me, and I am very excited to get started,” he says.

Recruiting graduate students to the cause is an essential task.

“I need to find people who are very motivated and smart but also really good in the lab,” Filion says. “That’s a unique brand of student: ones who can set up and dismantle experiments quickly. It’s exciting, relevant and important work because a lot of the municipal systems are getting really old and producing water quality problems.”

Filion says the drinking water discolouration facility should be complete early in 2016. Once it’s up and running, he says, it’s only a matter of plunging into the research.