Infrastructure’s impact: How public transit investments affect our environment

Professor Shoshanna Saxe (CivE) analyses the environmental and social impact of large public transit infrastructure projects, informing policymakers as they decide which investments to make. (Photo: Tyler Irving)
Professor Shoshanna Saxe (CivE) analyses the environmental and social impact of large public transit infrastructure projects, informing policymakers as they decide which investments to make. (Photo: Tyler Irving)

Professor Shoshanna Saxe (CivE) analyses the environmental and social impact of large public transit infrastructure projects, equipping policymakers with data as they decide which investments to make. (Photo: Tyler Irving)

 

This story originally appeared at U of T Engineering News

The benefits of building public transit include reducing greenhouse gas emissions, relieving traffic congestion and expanding a growing city. Yet each transit project is unique, and predicting its future effectiveness is difficult. Professor Shoshanna Saxe (CivE) crunches the numbers on existing infrastructure to provide key decision-makers with a ‘reality check’ on the environmental and social impacts of today’s transit investments.

“Engineers usually aren’t involved in policymaking, and policymakers usually aren’t involved in engineering,” says Saxe. “I’m trying to bridge that gap.”

Saxe joined U of T Engineering in August 2016. Before completing her PhD at the University of Cambridge, she spent three years at a major consulting engineering firm in Toronto, working on projects such as the Eglinton Crosstown transit line and the Toronto-York Spadina subway extension.

“I love design, it’s amazing,” she says. “However, when you’re building things that people are going to use, you have to stay well within the limits of what you know for sure. I was curious about questions that we didn’t already know the answers to.”

During her PhD, Saxe conducted a detailed analysis of the London Underground’s extension of the Jubilee Line, completed in 1999. She gathered data on the greenhouse gases produced during construction and operation of the line, then used transit and land-use surveys to estimate the reduction of greenhouse gas emissions attributable to people using the line and living near it. By combining the two, she could calculate the net environmental benefit of that transit project.

“It turned out to be a bit of a mixed bag,” she says. “If you make some optimistic assumptions, you could say that it broke even in terms of greenhouse gas emissions around 2012 or 2013. If you are more pessimistic, you’re looking at a greenhouse gas payback of twice as long.”

Saxe says that the Jubilee Line extension sees approximately 175 million trips per year. On projects where ridership is low, the environmental payback period can be much longer. Saxe also studied the Sheppard subway line in Toronto, and found that with a much lower ridership it initially struggled to provide greenhouse gas savings. Over time, the Sheppard Subway Line has benefited from the decreasing emissions associated with electricity in Ontario. The results of the Sheppard Subway study were recently published in the journal Transportation Research Part D: Transport and Environment.

“If you’re at Don Mills station, and you want to go north, east, or even southeast, the network doesn’t serve you yet,” she says. “We still see people from that area driving 70 per cent of the time, so unfortunately there’s just a lot less opportunity for savings.”

Saxe says that her dream project would be to follow a major piece of infrastructure, such as a new transit line, from its conception through construction and use for 20 or 30 years — essentially throughout her career.

“I want to answer questions like: why did we originally build it, how did we originally build it, how did it perform over its lifetime, how did we maintain it and what did it need?” she says. “If we know how our present decision-making affects things decades from now, we can make better decisions.”

Concrete check-up: Fae Azhari develops diagnostics for critical infrastructure

Professor Fae Azhari (MIE, CivE) holds a sample of the self-sensing concrete she designed. Her work helps monitor the structural health of crucial infrastructure such as bridges, roads and hydroelectric dams. (Credit: Roberta Baker)

This story originally appeared on U of T Engineering News.

Canada will spend $125 billion on infrastructure maintenance and expansion in the next 10 years. Professor Fae Azhari (MIE, CivE) is helping stretch those dollars farther by keeping our buildings, bridges, roads and reservoirs safe and structurally sound for longer.

Azhari’s research focuses on structural health monitoring. Just as you visit the doctor for periodic check-ups, structures need their health checked too — but instead of blood tests and heart rate measurements, engineers usually perform visual inspections and spot-checks with sensors and instruments.

“The problem with visual inspections is that they’re pretty subjective, and with periodic monitoring, you can miss certain events or failures,” says Azhari. “Now we’re moving toward continuous monitoring by incorporating permanent sensors on important structures to get real-time data.”

Degradation or damage suffered between inspections can have catastrophic consequences. In June 2013, a rail bridge just outside of downtown Calgary partially collapsed as a train was passing over it. The train, carrying flammable and toxic liquids, derailed. Emergency measures were taken to prevent the railcars from falling into the Bow River, which was running high with summer floodwater. The Transportation Safety Board of Canada determined that floodwaters had eroded the soil around the bridge’s foundations, causing the collapse. This loss of sediment from around foundational supports is called scour.

“Believe it or not, this happens very often, especially in North America and some Asian countries,” says Azhari. “Scour is a huge problem.”

For her PhD research at the University of California, Davis, Azhari tackled scour from a new angle: she took commercially available sensors that measure dissolved oxygen, typically used for agriculture or biological applications, and used them for sensing scour. Azhari’s design was to attach a number of oxygen sensors at increasing depths along the buried length of the bridge pier. If the pier is properly buried, the dissolved oxygen levels detected by the sensors should be very low — but as scour erodes the sediments and exposes the sensors to flowing water, the dissolved oxygen levels rise. As scour progresses, more and more sensors become exposed, indicating how badly scour is threatening the bridge’s structural integrity.

She has also worked on concrete sensors, including a design that integrates conductive carbon fibers and nanotubes into concrete, making it a self-sensing material. Measuring the resistance across the material reveals the stresses and strains on it. “This technology is well-proven in the laboratory, but moving it to the field is a big challenge,” says Azhari.

As she builds her research enterprise, Azhari plans to collaborate across disciplines and with key partners who could benefit from her sensors, as well her analysis and insight into the data that comes from them. “Transportation infrastructure, utilities, dams, power plants, wind turbines — basically any engineering system — needs maintenance and monitoring,” she says.

“It’s very important to get these sensors from prototype to implementation, and I want to work on that.”

Heat, housing and health: Marianne Touchie and the complexity of multi-unit residential buildings

Professor Marianne Touchie (CivE, MIE) is working with Toronto Community Housing and The Atmospheric Fund to better understand how changes to energy use affect indoor environmental quality in multi-unit residential buildings. Toronto Public Health is collaborating to use their data to inform policy. (Photo: Kevin Soobrian)

Professor Marianne Touchie (CivE, MIE) is working with Toronto Community Housing and The Atmospheric Fund to better understand how changes to energy use affect indoor environmental quality in multi-unit residential buildings. Toronto Public Health is collaborating to use their data to inform policy. (Photo: Kevin Soobrian)

Professor Marianne Touchie (CivE, MIE) is working with Toronto Community Housing and The Atmospheric Fund to better understand how changes to energy use affect indoor environmental quality in multi-unit residential buildings. Toronto Public Health is collaborating to use their data to inform policy. (Photo: Kevin Soobrian)


This story originally appeared at U of T Engineering News

This story is a part of a  five-part #RisingStars series, highlighting the work of our early-career professors.

In cities from coast to coast, condominium towers are being constructed at an unprecedented rate, with 30,000 new units added in 2015 to the Toronto market alone. This is driven both by recent advances in the design, engineering and construction of tall buildings, and a stark increase in demand for these multi-unit residential buildings (MURBs). “More people are moving downtown,” says Professor Marianne Touchie (CivE, MIE). “There’s very limited space, so we need high-density housing options and MURBs provide that.”

With a background in building science, Touchie studies the relationships between energy efficiency and indoor environment quality parameters, such as thermal comfort, in these high-density buildings. In Toronto, one of the largest suppliers of MURBs is Toronto Community Housing Corporation (TCHC), which owns 50 million square feet of residential space and houses 110,000 residents. Many of these are older buildings without air conditioning.

“A lot of these buildings rely on ventilation through the building envelope, which is not terribly effective. At the same time, we need to reduce our energy consumption and energy use,” she says. “But reducing energy usage has implications for occupants, and that’s what I’m interested in studying.”

Touchie is currently collaborating with The Atmospheric Fund (formerly the Toronto Atmospheric Fund) on a large research project—one that she has been involved with since her role as their Building Research Manager from 2014 to 2015. She and her colleagues are collecting data on energy consumption, temperature, humidity and carbon dioxide concentration in more than 70 apartments spanning seven different TCHC buildings.

“It’s probably the most comprehensive MURB monitoring project in North America, if not the world,” says Touchie.

They are also working with Professor Jeffrey Siegel (CivE), who is examining concentrations of formaldehyde, particulate matter and, through a partnership with Health Canada, radon concentrations. Touchie says that collaborations, such as those with TCHC, The Atmospheric Fund and Siegel, are critical to creating a comprehensive picture of the MURBs she studies. “Buildings are so complex,” says Touchie. “I have training in one particular area, but I’m not an indoor air quality expert. When we make changes from an energy perspective to the ventilation system, or the heating and cooling system, it has an influence on the air quality. Working with other experts, like Professor Siegel, we can gather data on all sides.”

Touchie’s findings with The Atmospheric Fund and TCHC have drawn the interest of Toronto Public Health. The agency is interested in the health impact of extreme heat, and the study has found that these TCHC buildings are often overheated, especially in the summer.

“Extreme heat is a health problem, especially for the most vulnerable populations,” says Sarah Gingrich, a Health Policy Specialist at Toronto Public Health. Very young children, the elderly and people with illnesses or taking certain medications are most at risk. “This work is providing evidence that excessive heat is a problem in older apartment buildings in Toronto. The research is showing that although the temperature cools down at night outside, in these buildings it rises during the day and they stay hot all night long.”

Touchie and her collaborators are finding that a major culprit for the inefficient heating and cooling performance is uncontrolled air leakage. These leaks often occur around windows, doors, exhaust fans and elevator shafts. But inefficiencies aren’t just a building issue: she adds that “because people can do whatever they want in their own homes, like open and close their windows, MURBs combine the complexity of high-rise buildings with the occupant wild card,” which makes managing the indoor environment even trickier.

“The study provides valuable information on Toronto apartment buildings that will help to inform policy development,” says Toronto Public Health’s Gingrich. “It fills a very important gap by providing up-to-date data that highlights some of the challenges in this type of building, and points to potential solutions.”

Next, Touchie hopes to expand her research to newer condos, where data is even scarcer. “They’re going up so quickly, and we really have no information about the quality of the indoor environment or their energy performance,” she says. “I am very curious whether their energy consumption matches the performance level promised at the design stage.”

Ancient microbes could offer insight on better mining wastewater strategies

Professor Lesley Warren (standing, at right) and her colleagues are mining the genomes of microbes that thrive in wastewater generated by the resource extraction industry. Insights into how these organisms derive energy from metals and sulphur compounds could lead to new strategies for preventing pollution and optimizing mine reclamation. (Photo courtesy Lesley Warren)

This story originally appeared on U of T Engineering News.

Professor Lesley Warren (standing, at right) and her colleagues are mining the genomes of microbes that thrive in wastewater generated by the resource extraction industry. Insights into how these organisms derive energy from metals and sulphur compounds could lead to new strategies for preventing pollution and optimizing mine reclamation. (Photo courtesy Lesley Warren)

Professor Lesley Warren (standing, at right) and her colleagues are mining the genomes of microbes that thrive in wastewater generated by the resource extraction industry. Insights into how these organisms derive energy from metals and sulphur compounds could lead to new strategies for preventing pollution and optimizing mine reclamation. (Photo courtesy Lesley Warren)

Wastewater from a mine doesn’t sound like a cozy habitat, but for untold numbers of microorganisms, it’s home sweet home. A new research project led by Professor Lesley Warren (CivE) will examine how these microbes make their living by studying their genes — an insight that could help further reduce the environmental footprint of the mining industry. The $3.7-million endeavour is funded in part by Genome Canada through the Large Scale Applied Research Projects (LSARP) program.

Extracting valuable metals such as copper, nickel and gold from rocks, which typically contain only a few weight percent metals, requires substantial amounts of water. All wastewater generated must be cleaned to strict federal guidelines before it can be discharged back into the environment. It is these wastewaters that the microorganisms studied by Warren and her team thrive in.

“These wastewaters contain a variety of sulphur compounds that certain bacteria can use for energy,” says Warren, who holds the Claudette Mackay-Lassonde Chair in Mineral Engineering at U of T. “Their ability to do so evolved billions of years ago, long before more complex life arrived on the scene. If the history of Earth were a 24-hour clock, they have been around for over 23 hours, while we humans have been around for only 17 seconds.”

However, our ability to investigate these bacteria and most importantly how they are cycling these sulphur compounds, which will influence the quality of mining wastewaters, has been very limited until now. If these sulphur compounds become too concentrated, the company has to implement costly chemical treatment systems to make the water acceptable for release and avoid toxicity problems in lakes or streams downstream from the mine.

Dr. Lesley Warren is the Claudette MacKay-Lassonde Chair in Mineral Engineering within the Department of Civil Engineering.

Dr. Lesley Warren is the Claudette MacKay-Lassonde Chair in Mineral Engineering within the Department of Civil Engineering.

Warren believes that genomics can help. She has spent years travelling mine sites from Canada to South Africa to better understand the sulphur geochemistry of their wastewaters and how bacteria are implicated. “I have always preferred dirty water to clean,” she jokes.

For this project, Warren and her team will apply genomics directly in tandem with comprehensive geochemical analyses and modeling to wastewaters. She will collaborate closely with Professor Jill Banfield, a trailblazer in environmental genomics at the University of California, Berkeley, Professor Christian Baron, a microbial biochemist from the Université de Montréal, and Dr. Simon Apte, a research scientist in analytical chemistry and geochemical modeling from Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO) Land and Water in Australia, to unravel the role played by these sulphur-loving microbes in important geochemical processes affecting mining wastewaters.

“Mining companies know that microorganisms are driving these reactions, but its still a black box” says Warren. “The lack of available technologies has meant that there has been little research to determine which bacteria are doing what, which ones could serve as early warning signals, or those that could actually be used as the biological treatment itself. Most importantly, mining companies don’t know which levers to pull to control the system.”

Those levers are what Warren and her colleagues aim to identify. Informed by genomic and geochemical insights they plan to develop new tools that can help mine managers make better decisions about how to manage their wastewater. “Once we understand the microbes and how they affect wastewater geochemistry, we can pinpoint the drivers of their behaviour: Which wastewater compounds are they using? Do they like it hot? Do they like it cold? We can adjust those drivers to design new processes that do what we want them to do. Essentially we are mining the bacteria that already exist in these wastewaters as a biotechnology resource.”

With this new knowledge, mines could ensure conditions that encourage the growth of organisms that break down toxic compounds, or prevent the growth of organisms that produce those toxic compounds in the first place. The team is collaborating with three Canadian mining companies, as well as two engineering consulting firms, Advisian and Ecological and Regulatory Solutions. In addition, the Mining Association of Canada, the Ontario Mining Association and CSIRO are further supporting the project.

The project also has the endorsement of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM), the leading not-for-profit technical society of professionals in the Canadian minerals, metals, materials and energy industries. CIM National Executive Director, Jean Vavrek, commented: “CIM are in full support of this exciting new project.  While genomics itself is relatively new to the mineral resource industry, it has the potential to provide significant returns and generate new areas for investment in the sector.  We consider this a flagship project and will continue to follow Dr. Warren and her team closely as they pioneer genomics research for mine wastewater characterization and possibly treatment.”

“The mining industry has driven this project from its inception because they want to reduce their environmental footprint. Harnessing the biological potential of their wastewaters will facilitate the development of such strategies to achieve this goal,” says Warren. “So many of the organisms we’re finding are new to science. The chances that we are going to find organisms that are capable of doing creative things that could be useful are very high.”