Posts Tagged: Drinking Water

World Water Day 2021: Focus on CivMin’s water research

Monday, March 22 is World Water Day
- this year’s theme is 
Valuing Water. 

To celebrate, we’re highlighting the incredible research our
CivMin faculty and students are leading to preserve and value water. 


Prof. Jennifer Drake is a co-researcher at the Daniel’s Geen Roof Innovation Testing Laboratory (GRIT Lab). She’s currently working on connecting a greywater system that reuses storm water to irrigate the GRIT Lab's green roof, reducing the embedded energy and carbon.

Prof. Jennifer Drake

Please describe your area of research.

My group specializes in green infrastructure and works on urban drainage issues. While focus the three big technologies: permeable pavement, green roofs and bioretention system.


What projects are you currently working on?

We’re getting ready to try to connect a greywater system to the Daniel’s Geen Roof Innovation Testing Laboratory (GRIT Lab) to re-use stormwater for irrigation. This month we’ll be tracking the water quality in the cistern before connecting the system to our green roofs in May

Daniel’s Geen Roof Innovation Testing Laboratory (GRIT Lab).

What companies/organizations are you working with? (can we name them and/or tag?)

The John H. Daniels Faculty of Architecture, The Meadoway, TRCA, STEP_TRCA, Bioroof, Gro-Bark


Who is leading this research and how many are involved (breakdown of profs, students)?

The work is connected to the DesignLIFES’ CREATE Network. I am the lead investigator of this network which includes professors at UofT, UTSC, Ryerson University, Saint Mary’s University and University of Saskatchewan. The goal of DesignLIFES is to train the next generation of living and green infrastructure professionals.


What impact do these projects have on the larger scale?

Green roofs are a great technology but require irrigation to support plant growth. Most roofs are irrigated with drinking water! By re-using stormwater, we can significantly reduce the embedded energy and carbon associated with this technology.

The Meadoway in Scarborough is a is a world-class example of innovative and forward-thinking land management. By re-introducing meadow vegetation within the Hydro corridor important ecosystem services are restored. This includes flood control, reduced urban heat island effects, urban biodiversity and, most of all, multi-functional public green space.

To read more about Prof. Drake's work visit




Drinking Water Research Group

The Drinking Water Research Group (Profs. Susan Andrews, Robert Andrews and Ron Hofmann) examines all aspects of drinking water. One area of research is in the removal of microplastics in drinking water as well as their occurrence in lakes and rivers.

From top left: Profs. Robert Andrews, Susan Andrews and Ron Hofmann

 Please describe your area(s) of research: 

  • Municipal drinking water treatment: Finding ways to address emerging contaminants and to protect the public, but more economically and effectively.
  • Examining treatment requirements to convert municipal wastewater directly into drinkable water. This is the wave of the future in many parts of the world. A lot of places are running out of water (e.g. Cape Town last year), so recycling the wastewater directly into drinking water is going to become more common. Technologically it’s feasible, it’s just very expensive, and we need to find the best and cheapest way to do it.
  • Investigating means to incorporate sustainable “green” technologies into drinking water treatment including the use of biological processes (biofiltration) in lieu of chemical addition.
  • Assessing the occurrence and removal of microplastics in drinking waters as well as their sources (lakes and rivers). A recent Toronto Star article reported, plastics in the environment are considered to be the greatest threat after global warming.
  • Optimizing treatment methods including the use of ultrafiltration membranes for some of the largest cities in Canada.


What projects are you currently working on?  

Prof. Ron Hofmann: A lot of small projects looking at how to best use current assets in Canadian drinking water treatment plants to be more effective and cheaper. Also, looking at how they might be able to address newly identified contaminants, such as PFAS or microplastics (this last one is Prof. Andrew’s work).

My own work focuses on activated carbon (the same stuff as the black charcoal in aquariums), and on using UV light to disinfect the water and to destroy chemicals. UV is relatively recent and is very cheap and effective. I have a small project on harnessing sunlight to drive photovoltaic-based UV water treatment for remote and resource-poor parts of the world.

Prof. Robert Andrews: I have major ongoing projects that examine the occurrence of microplastics in Canada as well as elsewhere in the world including Singapore. This work focuses on their removal during drinking water treatment as well as during water reuse (when converting municipal wastewater into drinking water)

Prof. Susan Andrews: My research interests are somewhat eclectic, but they generally include some aspect of the chemistry of drinking water treatment processes or distribution systems. For example, we are beginning some work on some small-scale water mains to see if we can improve the way that chlorine protects the treated water as it travels from the treatment plant to our taps.

What companies/organizations are you working with?

Many of the largest water providers in Ontario (Toronto, York, Peel, Durham, Peterborough, Barrie, London, Ontario Clean Water Agency)


Who is leading this research and how many are involved (breakdown of profs, students)? 

The three professors in the DWRG (Profs. Robert Andrews, Susan Andrews and Ron Hofmann) and approximately 30 personnel (Undergraduate students, Graduate students, Post-doctoral fellows, Research assistants).


What impact do these projects have on the larger scale? (In what way will engineering address the problems to make the world a better place?) 

Improving drinking water quality, learning more about emerging contaminants that we should address through new regulations.


To read more about the DWRG, please visit




Ground & Surface Water

Prof. Elodie Passeport’s research explores the environmental remediation of contaminated surface and groundwater, primarily working on two types of green infrastructure: Constructed wetlands and bioretention cells. Her goal is to improve the reliability of green infrastructure.

Prof. Elodie Passeport


Please describe your area of research: 

My research focuses on environmental remediation of contaminated surface- and groundwater in urban, agricultural, and industrial settings. My approach is to characterize the transfer and transformation mechanisms that govern the fate and removal of contaminants in natural and engineered aquatic environments. Human activities use thousands of chemicals that reach stormwater, wastewater, and our freshwater aquatic resources. Some of these chemicals have known impacts on human and environmental health, but many are still to be discovered or are unregulated due to lack of knowledge about their toxicity.

The goal of my research is to improve the design and implementation of remediation measures. To this end, my research seeks to evaluate the efficiency of natural attenuation in contaminated groundwater and green infrastructure. I primarily work on two types of green infrastructure: constructed wetlands and bioretention cells. In support of this goal, my research group also develops new analytical methods based on stable isotopes.

Green infrastructure is a cost-effective and energy-efficient approach to water treatment but must become more reliable before it sees widespread adoption. While in principle wetlands and bioretention cells can eliminate a significant portion of contaminants, their present-day performance is highly variable. My objective is to improve the reliability of green infrastructure by advancing our understanding of their internal processes.


What projects are you currently working on? 

There are a few exciting projects in my group on two main topics: 1) Microplastic Research and 2) Stable Isotope Analysis.

  • Microplastic research

Microplastics are small plastic particles, in the 1-5000 µm range, that are widely distributed in the environment, and whose toxicological effects are mostly unknown. In collaboration with Prof. Chelsea Rochman (Ecology and Evolutionary Biology) and Prof. Jennifer Drake, our PhD student Kelsey Smyth has conducted the first comprehensive study of microplastic fate in bioretention cells. This two-year long field work showed an 84% decrease in median microplastic concentration between the inlet and outlet of a bioretention cell. Her work showed that atmospheric deposition was a significant source of microplastics – especially microfibers – in urban stormwater, and urban stormwater was a significant pathway of microplastics to downstream aquatic ecosystems. Green stormwater infiltration systems like bioretention cells have great potential to limit this pollution.

Future research will evaluate if existing total suspended solids models can be used to characterize the fate and removal of microplastics in bioretention cells to better understand if accumulation in the cell is a significant issue.

Figure 1: graphical abstract from Smyth et al. 2021.

2) Compound Specific Isotope Analysis (CSIA)

Compound Specific Isotope Analysis (CSIA) is now an accepted diagnostic tool for identifying and quantifying the transformation of traditional contaminants, e.g., toluene and chlorobenzenes, in groundwater. My group is developing new analytical methods for stable isotope analysis of non-traditional contaminants (e.g., trace organic contaminants). We are also developing new applications of CSIA in less explored environments such as surface water.

Figure 2. CSIA to distinguish transfer and transformation mechanisms

Langping Wu, a postdoctoral fellow in my group is investigating the reaction mechanisms that govern the aqueous phototransformation of benzotriazole, a corrosion-inhibitor present in urban stormwater and wastewaters. Using stable carbon, hydrogen, and nitrogen isotope analysis, we found a pH-dependence of benzotriazole direct photolysis which can be explained by a complex contribution of different reaction mechanisms. With PhD student Suchana Shamsunnahar, we have developed a novel method for CSIA of NO2- and NH2-substituded chlorobenzenes. These are common groundwater contaminants that raised significant concern for human and ecosystem health. We are working on a complex highly contaminated industrial site in Brazil with multiple academic and private partners and have proposed a novel method based on passive integrative samplers to conduct CSIA down to very low concentrations.

Altogether, these results demonstrate the potential to use CSIA as a diagnostic tool to monitor contamination and remediation in the field.


What companies/organizations are you working with?

Microplastics work: Toronto and Region Conservation Authority (TRCA)

CSIA: Geosyntec Consultants, Corteva Agriscience


What impact do these projects have on the larger scale? (In what way will engineering address the problems to make the world a better place?) 

Cleaning up water using passive remediation solutions (green infrastructure such as bioretention cells, constructed wetlands) and developing new diagnostic tools to monitor remediation.


To read more about Prof. Elodie Passeport’s work, visit



Warren Lab

Mining, Water and Environment

Prof. Lesley Warren's research examines the largely unexplored bacteria present in mine wastes and impacted waters to generate innovative new technologies that will enhance the environmental practices of the mining industry.

Prof. Lesley Warren, Director of the Lassonde Institute of Mining

What projects are you currently working on? 

The Mining Wastewater Solutions (MWS) Project is developing better tools for reactive sulfur compounds management. Funding for this project come from our mining partners and  Genome Canada and  Ontario Research Fund - Research Excellence (ORF-RE).

My group is also leading a project to constrain sulfur risks to oxygen levels in Syncrude Canada’s first pilot wet reclamation project, Base Mine Lake (BML). Funding for this project comes from Syncrude Canada and NSERC.


What companies/organizations are you working with? 

For the MWS project, we are working with Glencore Sudbury INO, Hudbay Minerals, Rambler Metals and Mining, Ecoreg Solutions and Ecometrix Consulting Companies.

For the BML project, we are working with Syncrude Canada and COSIA.


Who is leading this research and how many are involved(breakdown of profs, students)? 

I am the Principal Investigator on both projects (both international).

For the MWS project there are three professors from three institutions, three research scientists, one field researcher, 10 students, four post-doctoral fellows and two research assistants involved. 

For the BML project there are three professors from three institutions, one field researcher, 12 students and three post-doctoral fellow involved with the project.

Researchers collecting samples

What impact do these projects have on the larger scale? (In what way will engineering address the problems to make the world a better place?) 

Mining requires huge amounts of water to extract valuable commodities and generates massive amounts of wastewater that must be cleaned according to strict environmental standards before being discharged.  This wastewater also provides an ideal habitat for microbes, and studying these can help reduce wastewater treatment costs and the environmental footprint of the mining industry.

My research focuses on identifying the microbes that occur in these contexts and how they drive changes in water quality or waste stability. These new discoveries  are leading to new models and tools that tackle the underlying root causes of potential risks to the environment.


To read more about Prof. Lesley Warren's work, visit 

Microplastics in drinking water: how much is too much?

Professors Chelsea Rochman (left, Ecology and Evolutionary Biology) and Bob Andrews (right, CivMin) have joined forces to develop new techniques for analyzing microplastics and nanoplastics in drinking water. (Photo: Tyler Irving)

Is there plastic in your drinking water? Professors Bob Andrews (CivMin) and Chelsea Rochman (Ecology and Evolutionary Biology) say there is — but right now, researchers don’t know much more than that.

“If someone asks me how microplastics in drinking water influence human health, I have to say that we have no idea,” says Rochman. “But we should be concerned that the mismanagement of our waste has come back to haunt us.”

Plastic never really goes away. While some waste plastic is recycled or incinerated, most ends up in landfills or worse. A world-leading expert on the fate of plastic waste, Rochman has documented how it ends up in oceans, lakes, rivers, as well as along their shores and even in the bodies of aquatic animals.

“All of the big stuff that you see eventually gets broken down by sunlight into smaller and smaller pieces,” she says. When they become small enough a microscope is required to see them — anywhere from a few millimetres down to a few micrometres — they are referred to as microplastics.

As with larger plastic pieces, microplastics are found widely in the environment. Rochman and her team have even extracted them from the bodies of fish for sale in a commercial market.

Concern over microplastics has been floating just below the surface for some time, but it wasn’t until the fall of 2017 that the issue of microplastics in drinking water hit headlines in a big way.

A non-profit group called Orb Media took samples of tap water from around the world, found microplastics in most of their samples, and released their results to the media. As a member of both the Drinking Water Research Group and the Institute for Water Innovation, Andrews knew that his collaborators would be curious about the story.

“Within hours, I got calls from a couple of the major water providers in southern Ontario that I work with, asking me what we were doing on this topic,” he says.

Despite his long experience collaborating with drinking water providers on treatment and technology, Andrews had not researched the issue of microplastics before. So he sought out advice from Rochman, who at first was similarly skeptical.

“I said, ‘I don’t think they’re going to be there, but sure, let’s filter some water and have a look,’” says Rochman. “We did, and they were there.”

Rochman and Andrews examine tiny plastic particles extracted from Toronto’s harbour. Even smaller particles — micrometres in size — have been found in drinking water from around the world. (Photo: Tyler Irving)

The traditional approach to dealing with drinking water contaminants, such as heavy metals or organic compounds, is for scientists to determine a target threshold below which the risk to human health is considered minimal. Drinking water authorities then invest in treatment technologies designed to keep the levels of these contaminants below the threshold.

But there is no existing threshold for microplastics, and developing one will be complex for several reasons.

First, plastic interacts differently with the body depending on how big the pieces are. “What we’ve seen in animals is that larger pieces usually just get excreted,” says Rochman. “But the smaller particles can actually leave the gut and go into tissues, which is when you can get inflammation and other problems.”

Another challenge is that there are no standardized methods for testing levels of microplastics in drinking water. Different teams employing different techniques could obtain different results, making it hard to compare scientific studies with one another.

Contamination is also an issue — tiny plastic particles shed from clothes, carpets and upholstery can get into the samples and skew the results.

These challenges are further compounded by the fact that microplastics can break down into even smaller particles, known as nanoplastics. Nanoplastics may behave differently from microplastics, but information is scarce because methods for detecting them are not merely non-standardized — they haven’t even been invented.

“Right now, we don’t have good techniques for handling nanoplastic particles,” says Andrews. “One strategy we’re considering is to concentrate them, burn them, and analyze the gas to determine what types of plastic are there. We’d then have to back-calculate to determine their initial concentrations.”

Andrews and his team also have experience testing the toxicity of various compounds on cells grown in the lab. While they may one day go down this route for nanoplastics, for now Andrews and Rochman emphasize the importance of improved analysis as a key step toward developing policies to address the challenge of microplastics.

“California has already passed laws mandating the monitoring of microplastics in drinking water and in the ambient environment,” she says. “I think it’s good that those bills happened, because they are now forcing this global methods development program, which we’re helping lead. We don’t want to throw out numbers until we feel that we have a sound method.”

The collaboration between Rochman and Andrews is funded in part by XSeed, an interdivisional research funding program designed to promote multidisciplinary research. XSeed projects include one principal investigator from U of T Engineering and one from another University of Toronto division, in this case, the Faculty of Arts & Science.

Learn more about the latest cohort of projects funded through XSeed

“Dealing with microplastics is the kind of challenge that truly does require people from different disciplines to work together,” says Andrews. “Neither of us could do this alone.”


By Tyler Irving


This article originally posted on U of T Engineering News 

Leading the way on lead research

Researchers aim to prevent a Flint-like crisis from happening in Canada

An interview with Prof. Robert Andrews, Sarah Jane Payne (Post-Doc) and Aki Kogo (MASc Candidate).

In 2014, the city of Flint, Michigan, switched its water source from Lake Michigan to the Flint River. Inadequate treatment and reporting caused lead (Pb) contaminated drinking water to be delivered to Flint residents, resulting in a state of emergency being declared.
Researchers at the University of Toronto’s Drinking Water Research Group (DWRG) have been actively studying the behaviour of lead (Pb) in water distribution systems since 2012, with a particular focus on southern Ontario drinking water sources.
“The problems in Flint emerged because the alternate water source had a slightly different water chemistry that disturbed the protective lead (Pb)-scale on the existing lead (Pb) pipes,” said Prof. Robert Andrews, a principal investigator with the DWRG. “Short of replacing all the lead (Pb) service connections in the system immediately, it will take time for the damaged scale on the interior of the pipes to build up with time and repair itself.”

Sarah Jane Payne, U of T Post-Doctoral Fellow, explains that scale (the buildup of materials lining the inside of water pipes), much like rust, can be relatively stable. However, it can cause significant issues when disturbed, as it was with the water change in Flint.
“Municipalities add different chemicals, called corrosion inhibitors, to the local water, which react with dissolved lead (Pb) in the water and re-deposit it on the surface of the pipe to form the scale,” Payne describes. “Each water source (lake or river) has a different chemistry, such as alkalinity, pH and inorganic carbon, which affects how the corrosion inhibitors react.”
“The crisis in Flint highlighted what many people take for granted,” said Andrews. “Researchers are aware of real-life issues and through careful experimentation are always looking for unintended consequences. Asking ourselves if we make one change, how is this going to affect something else?”

The science of inhibitors

As far back as the fourth century B.C.E, the ancient Greeks preferred terracotta pipes over lead (Pb). They knew, even then, that lead (Pb) negatively impacted health. Today, we know lead (Pb) is a powerful neurotoxin with serious implications for neurological development in children. Despite this, lead (Pb) has persevered as a material for pipes due to its durability and ease of use. Lead (Pb) service lines, connecting the water main to the home, were widely employed in North America until the early 1950s, when regulations ended the use of lead materials for new lines.

Municipalities today use a variety of methods including the application of corrosion inhibitors, like orthophosphate and zinc-orthophosphate, to reduce the amount of lead (Pb) consumed by the general population. These chemicals react with lead (Pb) to form a compound that precipitates out of solution to form a stable, crystal-like lining on the inner surface of the pipe. The lead (Pb)-scale is very thin – only a few microns thick.

The problem can be made even more complex when considering physical disturbances, changes or fluctuations in water chemistry, and seasonal changes in temperature, which can loosen existing scales and disrupt the chemical balance between the water and the pipes.

Utilities try to form the strongest scales possible given varying water chemistry. Local water quality conditions dictate what needs to be changed or added to reduce corrosion.

“When phosphate-based corrosion inhibitors are used, lead (Pb)-phosphate scales become more and more stable over time,” said Andrews. “Understanding that chemistry and timeline is actually quite complex.”

“Reducing corrosion isn’t just about adding corrosion inhibitors. It can also be about changing the attributes of the water itself, such as adjusting the pH,” said Payne. “It is being aware of these details, looking at them holistically that determines what combination of attributes and additives might lead (Pb) to the least amount of lead (Pb) in drinking water.

Study: Comparing inhibitors

Researchers with the DWRG wanted to compare corrosion control options for Lake Ontario water using the two most common corrosion inhibitors: zinc-orthophosphate and orthophosphate. However, as phosphates are a finite resource, sodium silicate was also selected as a non-phosphate-based inhibitor to research.

“Phosphates are expensive and the price is volatile, so we wanted to include an alternative. That’s why we looked at sodium silicate,” said Payne. “Sodium silicates’ corrosion inhibitor properties have been known since the 1920s, but the funny thing is that no one really knows exactly how they work. So we compared it to the performance of phosphate-based inhibitors to try to understand more about this corrosion inhibitor.”

IMG_0613To fully understand how Lake Ontario water will interact in local water distribution systems, lead (Pb) pipes that had been in use for 65 years were sourced. To simulate a scenario where a homeowner has not replaced their portion of the water service line, a partial lead (Pb) service line replacement was set up in the DWRG laboratory.

“All of our test pipes came out of a community in Ontario. When you think about these pipes, many have been underground since the 1940s. They’ve had decades of different chemical combinations pass through them,” explained Payne. “What their particular scale is formed of and what conditions keep them stable is not well understood. We use real lead (Pb) pipes that have been pulled out of the ground that we know have a history. We can do more realistic experiments with those because using a new lead (Pb) pipe would be a totally different story.”

“Both phosphate-based inhibitors performed very well, though zinc-orthophosphate did seem to perform a little better,” said Aki Kogo, MASc Candidate. “Initially, the sodium silicate did not do very well but later in the experiment we started to see some better results with it.”

Now that testing has wrapped up at the DWRG lab, this setup of lead (Pb) testing equipment will be moved to a municipality’s water treatment facility for future studies.

“It’s through a lot of hard work by smart people that this research gets done,” Payne said. “Just to get the water every week, Aki and Jim Wang [DWRG Research Chemist] transported 500 litres of ‘untreated’ water back to the tanks in our lab. There is so much physical work, time and intellectual dedication that goes into research like this.”

The impact of research

“People in the water industry are very passionate about public health and that’s always at the forefront of any water treatment research,” explains Andrews.

“What we do every day affects millions of people. Our research is done quietly, but it’s really quite important. There are strong researchers in Canada, who are truly focused on the health of Canadians and those around the world.”

Public health plays a significant role in directing the research on drinking water quality.

“There’s the epidemiology and toxicology side that drives the health-based inquiry,” said Payne. “The engineering side looks into accomplishing what is required to meet the standards set by health-based researchers. It is a back and forth iterative process that helps regulators set standards that municipalities must meet.”

“In Canada, we have a lot of utilities that are forward thinking,” explains Andrews. “It is extremely rare for a municipality to change its water source. Because of the safeguards in sampling and reporting that we have in Canada, along with the conscientiousness and vigilance of water treatment personnel, it is very unlikely that a Flint-like emergency situation will happen in Canada.”

About the Drinking Water Research Group

The Drinking Water Research Group (DWRG), formed in 1998, is a consortium of researchers from the University of Toronto. The group operates as a team working to improve drinking water quality through sound research and engineering. With over 25 ongoing projects, the DWRG typically undertakes collaborative projects examining treatment, distribution, compliance and innovation to meet future water needs. Unique resources, including a large number of municipal and industrial partners, allow for various issues to be examined.



Robert C Andrews: high-tech solutions for cleaner, safer drinking water

Recipient of the Dr. Albert E Berry Medal for outstanding contributions to environmental engineering

Professor Robert C Andrews (left) with Profs. Ron Hofmann and Susan Andrews in the Drinking Water Environmental Labs

Prof. Robert C Andrews, PEng, of the Drinking Water Research Group (DWRG) in the University of Toronto’s Civil Engineering Department, accepted the Dr. Albert E Berry Medal at a Canadian Society for Civil Engineers gala on Friday, June 3. The award, determined by a jury of peers, recognized the work and impact that Andrews’ research has on drinking water.

“I have such great respect for my peers, and to be selected by them to receive this award is such an honour,” said Andrews. “Our work, with industry and municipal partners helps provide clean drinking water to millions of consumers.”

The DWRG has over 25 projects ongoing at any one time. These include collaborative research in the application of membranes to drinking water treatment and examining the potential to remove emerging compounds including pharmaceuticals. Andrews also examines the use of alternative disinfectants for drinking water treatment, which has produced a baseline of knowledge that was previously lacking. The Ontario Ministry of the Environment has incorporated this data into their disinfection regulations.

Andrews began his career at the University in 1993 in the Department of Civil Engineering in the Faculty of Applied Science and Engineering, where his research interests included the examination of technologies for removing emerging contaminants in drinking water as well as the reduction of risk that they pose to consumers. Andrews has held an NSERC Senior Industrial Research Chair in Drinking Water Research since 2007.

A consultant as well as a professor, Andrews serves on a number of decision-making committees and advisory councils in Canada and around the world. Health Canada, the Ontario Ministry of Environment and the Ontario Drinking Water Advisory Council have all benefitted from his expertise.

Andrews is the recipient of the Dr. Albert E Berry Medal for Outstanding Achievement in Environmental Engineering by the Canadian Society for Civil Engineers, which recognizes outstanding achievements in environmental engineering; by protecting public health and the environment while preserving our air, water and land resources for future generations.

© 2021 Faculty of Applied Science & Engineering