Treating Water to Reduce Environmental Impact

As an Engineer/Researcher in the field of water treatment, Mathieu Lapointe is concerned about the accumulation of contaminants that are released into natural waters, and especially the Saint Lawrence River. “It’s a problem for aquatic ecosystems and for human health.” We eventually drink the water from the River.

In light of this, Mathieu has decided to focus on finding solutions for capturing refractory contaminants that can’t be removed during conventional treatment technologies.

There you have it! Flocs in the Sieve!

Mathieu Lapointe is professor-researcher in the Construction Engineering Department at ÉTS.

According to Mathieu Lapointe, if micro-contaminants are able to pass through contaminated water filtration systems, we should increase their size. He focuses his research on converting minuscule contaminants into flocs, or aggregates of fine particles. Drawing inspiration from the capacity of bathroom tissue to agglomerate, Mathieu modifies the surface of a long cellulose-based fibre onto which pollutants can agglutinate. Then he adds another fibre, and another, until the nano-contaminants are imprisoned within a jumble of fibres, which is then removed by the “sieves” at the water treatment plant. Mathieu explains: “These flocs are 10 to 20 times larger than what we were previously able to form, which significantly increases their retention during settling and filtration.”

His work has been published in a number of prestigious scientific journals, including Environmental Science and Technology, Nature, npj/Nature clean water and Nature Sustainability.

After dedicating many years to researching innovative processes, Mathieu Lapointe expanded his areas of expertise to now encompass four separate aspects: The production of drinking water, the treatment of domestic wastewater, the treatment of industrial wastewater, and a field that is becoming more and more important to municipalities, the management of stormwater. “We may have minimized the risk of stormwater in the past, but we now have a better understanding of its toxicity,” the engineer admits.

Runoff is not Safe to Drink

Covered in concrete and asphalt, our cities have become waterproof. The only place rainwater can go is into the sewers, bringing with it micro-plastics, pesticides, pieces of Big Macs, tire residue, de-icing salt and all sorts of pollutants that accumulate on the streets of Montréal. What can be done?

Engineers seek low-cost solutions for treating stormwater that is filled with contaminants before it reaches the River. Mathieu explains the principle behind the infiltration zones and stormwater retention ponds that are being systematically installed in strategic locations across the City. These reservoirs are used for the settling and filtering of contaminants. Another possible approach is to replace the large waterproof surfaces at shopping centres with grassy parking areas. “As Civil Engineers, we are attempting to go turn back the clock: Changing impermeable areas into porous spaces that can absorb rainwater.”

Standard Contaminants versus Emerging Contaminants

There are two types of pollutants found in all aspects of water treatment: standard contaminants, or those that are known and measurable; and emerging contaminants, which specifically include microplastics and residues of pharmaceutical compounds. Mathieu Lapointe points out: “We don’t really know how many contaminants are in the water, and we are still not accurately assessing their level of toxicity when they are released into the environment.” Even if only a small quantity manages to find its way into natural watercourses, the accumulation of these contaminants, which may not be biodegradable, remains a serious concern for researchers around the world.

ÉTS: Understanding How to Apply the Concept

Currently a Professor in the Environmental Engineering Department at ÉTS, Mathieu Lapointe would like to recommend that future engineers follow an approach that focuses on optimizing water treatment processes. He has long dreamed of being able to teach complex concepts and demonstrate their fields of application in real time. “I have always loved the excitement of knowledge transfer and scientific popularization!”

Mathieu Lapointe is an Engineer who is pursuing his research aimed at reducing the environmental impact of society on our water resources by creating decontamination solutions that can be used just about anywhere in the world.

About Mathieu Lapointe

Currently a Professor in the Construction Engineering Department at ÉTS, Mathieu Lapointe earned his Bachelor degree in Civil Engineering from Polytechnique Montréal, and then went on to pursue a Master degree in Environmental Engineering. However, it was while he was following the fast track toward a PhD at Polytechnique that his interest in the field of water treatment became his vocation.

Under the supervision of Professor Benoit Barbeau for his graduate and post-graduate studies, young Mathieu discovered the world of research, and he was hooked. He adopted the practical approach strategy that his Civil Engineering Professor at Polytechnique was known for focusing on finding solutions rather than focusing exclusively on disclosing the problems.

Mathieu continued to follow this invaluable advice during his post-doctoral fellowship at McGill University, under the supervision of Nathalie Tufenkji, internationally renowned Researcher and Full Professor of Chemical Engineering. He points out that she helped him to create his first materials, which began his journey off the beaten path, and where he started to think differently for the benefit of the environment and public health.

Mathieu Lapointe won numerous prizes as the Mitacs Award for exceptional innovation and the Honoris Genius Award, presented annually by the Ordre des ingénieurs du Québec, for is contribution related to the creation of the functionalized fibres.