As talk of deconfinement begins in Québec, two professors at Polytechnique Montréal’s Centre de recherche, développement et validation des technologies et procédés de traitement des eaux (centre for research, development and validation of water-treatment technologies and processes, or CREDEAU) are working on initiatives that could facilitate the resumption of activities here at home and elsewhere.
(Photo: Creative Commons CC0 1.0 licence)
The first initiative is to bring buildings back into use. As at Polytechnique, many have switched to “pause” mode in recent weeks, causing the water in their pipes to stagnate. This situation is ideal for the proliferation of pathogenic bacteria, such as legionella, as well as the accumulation of toxic metals, such as lead, in the pipes.
Bottom line, the cold and hot water systems in tens of thousands of buildings will soon have to be cleaned — and in a very short time period. This type of cleaning is essential to avoid health risks to users who use water in buildings.
Michèle Prévost, full professor in the Department of Civil, Geological and Mining Engineering at Polytechnique, wanted to guide managers who are wondering about the steps to follow for resupplying their buildings with water.
“Rarely are a building’s pipes shut down for several months as they are now,” says the holder of the NSERC Industrial Research Chair in Drinking-Water Treatment and Distribution. “Most of the time, we clean only internal networks when a new building is prepared for occupancy before it opens. With the current long period of disuse, these buildings will have to be put back into service before the occupants return, in order to restore water quality.”
Together with a group of American researchers, Professor Prévost sifted through the scientific literature on the subject, then condensed her observations in a recently published literature review. To ensure that their recommendations would be taken into consideration, the researchers then created a series of guidelines targeting specific groups, ranging from individual building owners to hospital managers and municipal water utilities.
Professor Prévost also coordinated the work of a committee whose members include the Régie du bâtiment du Québec (Québec construction board, or RBQ) and the Corporation des maîtres mécaniciens en tuyauterie du Québec (corporation of master pipe mechanics of Québec, or CMMTQ) to produce a flushing protocol for hot- and cold-water systems that can be used when opening restrictions are lifted.
“The goal is to produce simplified guides that ensure effective network cleaning,” says Professor Prévost. “We want the protocols for restoring water mains to service to be as clear as possible to guide managers of buildings, from the smallest to the largest.”
Where does SARS-CoV-2 fit in all this? The specialist is not worried about the possible presence of the COVID-19 virus in the pipes. “Drinking water does not contain COVID-19 because the virus is very sensitive to the chlorine in our drinking water. Tap water is not a source of exposure,” she says.
For her part, Sarah Dorner, also a full professor in the Department of Civil, Geological and Mining Engineering at Polytechnique, wants to track down the virus behind COVID-19 in Montréal’s wastewater by identifying and then quantifying its RNA (ribonucleic acid), the genetic material it uses.
“The presence of inactive viruses in wastewater is not a danger,” says Professor Dorner. “We want to use this information to support all the epidemiological work that is being done, and maybe anticipate the arrival of a second wave of infections.”
Professor Dorner’s team has already gotten down to work and has been collecting wastewater samples at the Montréal treatment plant since March. Each of these samples is now patiently waiting to be studied in a freezer at -80 degrees Celsius.
“We have many challenges to overcome,” Professor Dorner acknowledges. In addition to ensuring the safe transport of samples to the lab, her group must also obtain reagents that will detect the presence of viral RNA by reverse transcription polymerase chain reaction (RT-PCR). These reagents are the same ones used in some of the diagnostic tests for COVID-19. “The priority is really testing,” she says.
Other issues, such as the presence of inhibitors in the samples, will need to be resolved before regular analysis of the samples can begin. The researcher is working with other members of the Canadian Water Network, as well as a team from the Netherlands, to overcome these constraints.
Left to right: Michèle Prévost, full professor in the Department of Civil, Geological and Mining Engineering and holder of the NSERC Industrial Research Chair in Drinking-Water Treatment and Distribution. (Photo:Tom Morin Photographer); Sarah Dorner, full professor in the Department of Civil, Geological and Mining Engineering. (Photo: Denis Bernier Photographer)
Find out more
Professor Michèle Prévost’s expertise
Professor Sarah Dorner’s expertise
Website of the Centre de recherche, développement et validation des technologies et procédés de traitement des eau (CREDEAU)
Website of the NSERC Industrial Research Chair in Drinking-Water Treatment and Distribution
Website of the Department of Civil, Geological and Mining Engineering (In French)