We don’t usually think about what happens after we flush our sewage, but a team of scientists in British Columbia are experimenting with ways to turn wastewater into energy.
The team worked both in the lab and at the sprawling, 24-acre Lulu Island Wastewater Treatment Plant in Richmond, British Columbia, where they built a high-tech miniature wastewater reactor into which they introduced naturally occurring populations of organic-digesting microorganisms.
A byproduct of this process is biogas, which consists of methane, carbon dioxide and small amounts of other compounds such as hydrogen sulphide, nitrogen and oxygen.
It can be processed into a cleaner form to generate electricity. Those involved in the project say the most exciting part is how they are cultivating a population of microbes to produce more biogas.
“We’re creating the right environment for them to grow and thrive,” said engineer Lillian Zaremba, program manager for innovation partnerships at Metro Vancouver, the regional government of 21 municipalities in British Columbia’s Lower Mainland.
The project is being built at the Lulu Island Wastewater Treatment Plant, which treats millions of litres of wastewater from 220,000 homes in Richmond, about 20 kilometres south of Vancouver.
Microbes at work
Microbiology professor Steven Hallam of the University of British Columbia’s Institute of Life Sciences says the real magic happens at the microscopic scale.
“These invisible inhabitants that live in this man-made environment are actually doing all the work that ultimately leads to creating resources, renewable resources, from waste,” Hallam said.
“It’s like a circular assembly line. It’s an ecosystem.”
Hallam, who is part of teams pioneering ways to efficiently extract energy from wastewater that has been treated and released into the sea, hopes projects like this will change the way societies think about waste.
“We’ve been taught that dilution is the solution to pollution, right?” he said. “I mean, out of sight, out of mind.”
The Lulu Island Power Plant processes recovered methane and uses it to power the plant.
The surplus is sold to British Columbia gas supplier FortisBC, generating about $1 million a year, which is used to maintain the plant. Much of the research being done involves a large, silver, Willy Wonka-style gadget.
The device, called the “child digester,” has been installed at a wastewater treatment plant on Lulu Island, where it serves as a platform or on-site laboratory where tests can be conducted. In the child digester, microbes—called methanogens—break down waste.
The resulting methane gas is then piped to another series of structures that include a large, white bubble, where it is cleaned to the point where it can be mixed with the gas delivery system. The Lulu Island biogas plant began operating in 2021 and has cost $11 million to date.
It currently produces 60,000 gigajoules of energy per year. He says the goal is to scale up the system and eventually share the technology with 180 other wastewater treatment plants in Canada, but notes that could cost tens of millions.
According to the Canadian Biogas Association, there are 300 biogas projects in Canada using agricultural and landfill waste, generating enough energy to power about half a million homes a year.
Scaling up
In 2018, UBC microbiologists and environmental engineers began preliminary microbiological studies that ultimately led to the patented bioreactor plan.
Two research projects funded by the Natural Sciences and Engineering Research Council and Metro Vancouver’s Sustainability Innovation Fund have partnered to find ways to generate energy from wastewater and recover heat and ammonia from wastewater.
In 2022, the United States Patent and Trademark Office granted Metro Vancouver a patent for the Syntrophic Enrichment for Enhanced Digestion (SEED) system, a bioreactor designed based on experiments conducted in a pediatric digestive system.
Work is underway on a new bioreactor prototype, which should be completed by 2027. Zaremba says it will allow the project to scale up and produce methane by up to 50 percent, although they plan to start with 15 to 20 percent.
“If we can prove its success and that it makes positive business sense, it can be used in other places where biogas plants are located, and we can produce more renewable, low-emission natural gas, which will reduce our dependence on fossil fuels, and that will help our country achieve its climate goals,” Zaremba said.
He says the project contributes to the goals of British Columbia’s Clean Energy Act, which calls for 15 per cent of gas consumed in the province to be powered by renewable or low-emission fuels by 2030.
Real solution or marketing tool?
The concept “certainly seems novel,” according to Guru Gurumurthy, senior energy program analyst at the Toronto-based Pembina Institute, a think tank that promotes efficient clean energy transitions.
But he says the system isn’t cheap, noting that “it actually increases greenhouse gas emissions.” Gurumurthy sees wind or solar power as more cost-effective solutions because “they are the cheapest energy solutions that are available today.”
Other critics question whether extracting methane from biogas is the right solution to climate change, or whether it is simply another way to bring gas to market as a renewable energy.
Eddie Dearden says that after learning more about climate change about a decade ago, he gave up a career as a chemical engineer in the coal industry to pursue sustainable home design.
He has filed a complaint with the Competition Bureau of Canada criticizing gas companies for misleading consumers about the environmental impact of gas use. He is also one of the plaintiffs suing FortisBC for alleged “greenwashing” — using marketing to make a company seem more environmentally friendly than it actually is — and is campaigning for municipalities to change the term natural gas to fossil gas to make clear to the public the need to phase out the fuel in the face of climate change.
“They basically produce one of the most potent greenhouse gases — methane,” said Dearden, who believes Canada should move away from using the gas because it is too difficult to contain.
Zaremba says the Lulu plant is now reusing excess gas that was being flared. Selling it for use prevents methane from being released into the atmosphere, he says.
“We capture the methane, clean it up and burn it,” she said. “It would be great if we could go all electric and renewable solar or wind. I personally see that as a step in the energy transition journey.”
