Water: The wondrous tasteless and colorless liquid without which, all life on this planet would not exist. That miraculous conjoining of two hydrogen molecules and one oxygen molecule 鈥� without a doubt H20 is the most known chemical formula 鈥� is, next to the air we breathe, the most vital resource imaginable.
We drink it, cook with it, bathe with it, we use it to grow our crops 鈥� indeed industries in virtually every sector depend on it nearly as much as humans do to function. But, despite how dependent we are on it, we all too often take it for granted. Especially after it goes down the drain.
The reality is that treating wastewater is a crucial piece of human health. The Romans understood this and the sewage disposal systems they developed enabled the growth of large cities. But with the fall of their empire, the next millennium saw little development of wastewater treatment, resulting in the spread of disease for hundreds of years.
But water is not as widely available as it ought to be. According to the UN around 2 billion people worldwide do not have access to safe drinking water. And this is not just an overseas issue 鈥� water scarcity is a problem right here in Canada, too. While most Canadians enjoy access to safe drinking water 鈥� per capita consumption was 411 litres per day in 2019 鈥� there are still 28 Indigenous communities across the country with boil-water advisories in effect.
All of these issues have been preoccupying for 91社区 Chemical Engineering Professor Nathalie Tufenkji; she鈥檚 been interested in water treatment as far back as the 5th grade. It鈥檚 a passion that eventually led her to a bachelor鈥檚 degree in chemical engineering at 91社区, and then a Master鈥檚 and PhD from Yale University.
She returned to 91社区 in 2005 and launched the Biocolloids and Surfaces Laboratory. The laboratory researches water quality protection and nanomaterials in the environment along with other topics. Among her team was at the time postdoctoral fellow, Mathieu Lapointe who made a key discovery back in 2019.
鈥淭he first time I looked at wastewater under a microscope, I saw this fiber: it was toilet paper fibers that came from the contents of the toilet flush," he explains. 鈥淭hat's when I got the idea: what if we put more of these fibers in, what would happen?鈥�
Following his original discovery, the team realized that the addition of cellulose fibers from recycled paper in the water treatment process helped reduce the amount of chemicals needed to obtain clean water in the conventional water treatment.
Conventional large-scale water treatment systems use two central components, each composed of large water tanks. The first tank contains untreated water, along with different chemicals called coagulants and flocculants. These chemicals aggregate the contaminants in the water into groups called flocs. Once complete, the water is transferred to a second tank where the flocs eventually settle to the bottom in a process called sedimentation.
The settled flocs form a chemical slush at the bottom of the tank while the remaining water can move to the disinfection process (which usually involves chlorine or ozone, depending on the specific process used). But the slush still must be disposed of, usually by incinerating or burying it.
This process has high costs, according to Tufenkji. 鈥淭hat鈥檚 one of the reasons we鈥檇 like to reduce the amount of coagulant and flocculant, because when you鈥檙e using a lot of chemicals, the production and shipment of these chemicals has an environmental footprint,鈥� she explained.
The same is true for the infrastructure. The conventional system requires two tanks for the coagulation and sedimentation processes, which in turn requires pumps and plumbing to move the fluid between the tanks. What if there was a way to simplify all that?
From seeing Toilet Paper to using Cellulose Fibers
鈥淪o that鈥檚 where our really interesting alternative comes in,鈥� said Tufenkji, 鈥淲e can鈥檛 completely eliminate the need for coagulants and flocculants, but what we can do is add these cellulose fibers in and they act as super bridging agents to make flocs that are 10 times bigger and settle out much faster.鈥�
While it is impressive that they were able to obtain comparable water quality using less chemicals, that is not the only benefit. The inclusion of cellulose fiber and formation of 鈥渟uper鈥� flocs means that the amount of infrastructure needed to remove the flocs is also reduced.
"The science of coagulants is not new. We've been using them to treat water for over 100 years. But using another product, like cellulose fiber, that's completely new. It's never been tested before,鈥� recounts Lapointe. 鈥淭he main advantage is really the size of the flocs, which is unprecedented. And it removes more contaminants.鈥�
鈥淲e are reducing the environmental and also physical footprint of the plant,鈥� adds Tufenkji, 鈥淏ecause now you don鈥檛 need the second tank, and all the peripheral pipes and pumps that go with it.鈥�
The super flocs can be removed from the primary tank using a rotating screen, eliminating the need for a sedimentation tank. This double reduction both in the amount of chemicals used and the amount of infrastructure needed is game-changing technology. So far, lab results have been impressive, and the team is moving into the pilot testing stage.
鈥淲e think that this technology can help make traditional water treatment even more accessible, easier to implement and cheaper, and I think that will benefit a lot of marginalized communities,鈥� she said.
MIF support for the team
To help this project along, the team applied to receive support from the 91社区 Innovation Fund in 2021. Although they weren鈥檛 selected in the program鈥檚 first cohort, they successfully reapplied in 2022; the team was accepted into the second cohort. The team鈥檚 passion for their project is apparent and they are confident in the potential impact their new technology can have.
鈥淭his is our project, and we are really committed to seeing it to the end, and hopefully seeing it implemented all over the world,鈥� stated Tufenkji.
Following this goal, the MIF has been helpful in moving the project along. She speaks highly of the MIF鈥檚 research advisory board and the help they have provided the team in its trajectory towards commercialization.
鈥淭he members of the MIF鈥檚 research and advisory board have a very diverse expertise and it鈥檚 been really special and it鈥檚 helping us move the project along and now we can attract partners into signing a licensing agreement with us.鈥�
When asked about the best-case scenario with the technology鈥檚 future, Tufenkji stated 鈥淚鈥檓 really hoping that in five years our fibers will be replacing lots of chemical usage in water treatment plants all over the world.鈥�
