Spring Issue — April 2004
Out of Sight, but Never Out of Mind
When it comes to garbage, most of us drag our waste to the curb and never give it another thought. Not Leta Fernandes. The 1.5 kilograms of waste the average person throws out every day in this country is a source of concern for Fernandes and a catalyst for her research.A civil engineering professor at the University of Ottawa since 1989, Fernandes didn’t quite envision herself studying other people’s trash.
“You don’t start out thinking you are going to become an environmental engineer,” she said. Nevertheless, the interest in science was there from childhood, and with a family that was adamant about post-secondary education for all its children, Fernandes was definitely destined for university studies.
Growing up in Portugal, where clean drinking water and waste treatment were issues, Fernandes knew this was a field she needed to pursue. At first, she couldn’t decide between civil or chemical engineering. Drawn by a desire to address basic needs of the world’s population, Fernandes first studied in Lisbon, and graduated with a degree in civil engineering in 1979. She went on to complete her master’s and PhD in environmental engineering at McGill.
Fernandes’s research career started with the composting of manure slurries in a collaborative project with Agriculture Canada. A passive aeration method was found to be effective in producing an odourless, nutrient-rich growing material for plants. This system has recently been implemented in British Columbia.
It’s all pollution
“My research is mostly practical application, but I have evolved from studying the treatment of wastewater and agricultural waste to the safe disposal of waste in landfills. The basics are still the same. It’s still pollution.”One of Fernandes’s projects was to determine how to treat leachate, the material that sinks to the bottom of a landfill system. This leachate, or liquid wastewater, contains various pollutants such as heavy metals, organic materials, ammonia and boron. Conventional removal methods don’t work for boron, which is toxic to plants if it leaks into the subsoil below a landfill site. Studies on this issue are scarce, but Fernandes’s work using peat filters to absorb the chemical has led to an article soon to be published in the Journal of Environmental Engineering and Science.
A more recent project has involved the degradation of solid waste in a bioreactor landfill. Fernandes asks whether some of the pollutants in the leachate can be reduced. What kind of bacteria would optimize and speed up the breakdown of the waste, to reduce the need to scout out new landfill sites?
“But I didn’t stop there,” says Fernandes, whose current hot topic is how to optimize landfill cover designs to biologically oxidize fugitive emissions of methane gas into carbon dioxide and water. “The 30 to 40 per cent of methane that is not recovered migrates through the soil cap on top of the landfill and is released into the atmosphere, contributing to global warming,” says Fernandes. “About 20 per cent of Canada’s share of global warming comes from landfill sites, so there’s a lot of interest in solving this problem.”
Fernandes does not take credit for solving all the problems of landfill systems. “I couldn’t do this by myself. I have six graduate students, including two PhDs, working on these projects. There’s a lot of work to be done yet, but I think we are headed in the right direction.”
Hope for the future
When Fernandes arrives at her unadorned office in the old Colonel By engineering building, she doesn’t feel like she’s going to work. Rather, she feels a sense of hope for the future.“There are millions of people dying from poor sanitation and water-borne diseases,” says Fernandes, who has undertaken environmental projects in China, the Middle East and Africa. “It’s my belief that if you manage waste properly, you’ll significantly curtail your health bill. I want to be able to take this landfill technology and implement it at low cost in as many countries as possible.”