Science·What on Earth?

Cities are harvesting spoiled food to create new source of natural gas

In this week's issue of our environment newsletter, we examine how some Canadian cities are converting food waste into a form of natural gas and why fast fashion is a problem for the planet.

Also: Fast fashion has a sustainability problem

(Sködt McNalty/CBC)

Hello, people! This is our weekly newsletter on all things environmental, where we highlight trends and solutions that are moving us to a more sustainable world. (Sign up here to get it in your inbox every Thursday.)

This week:

  • Canadian cities are discovering a new energy source: Food waste
  • Water usage around the world
  • Fast fashion: Not a good look for the planet

Canadian cities are discovering a new energy source: food waste

(Peter Bromley/City of Hamilton)

It can be hard to imagine household food waste producing anything more than a putrid odour. But it's also a potential energy source.

In Canadian municipalities with green bin programs, household organics are collected at the curb and sent to a central facility where they are broken down by microorganisms. One result of this process is something called raw biogas.

A growing number of these cities are upgrading that biogas (from a methane concentration of 55 to 60 per cent to 90 per cent or more) to produce what is called renewable natural gas (RNG). RNG is similar in quality to conventional natural gas and can be injected into a natural gas pipeline to heat buildings and fuel vehicles.

The City of Toronto, for example, is getting into the RNG business by expanding and upgrading one of its organics processing facilities. Once the equipment is installed this year, the biogas will be "purified" to RNG and injected into Enbridge's natural gas grid.

"It seems like such a no-brainer, in my mind," said Carlyle Khan, a director in Toronto's solid waste management department. "I don't understand why other municipalities aren't doing it."

According to a 2013 study by the Canadian Biogas Association, capturing biogas from all potential sources (agriculture, landfill, wastewater and municipal organics) could produce 2.42 billion cubic metres of RNG annually and reduce Canada's greenhouse gas emissions (GHG) by 37.5 million tonnes — the equivalent of removing 7.5 million cars from the road.

Biogas harvested from residential organic waste alone could produce 140 million cubic metres of RNG and reduce GHGs by 2.2 million tonnes.

RNG is still very much an emerging field. According to Jennifer Green, executive director of the Canadian Biogas Association, there are only about 12 RNG facilities in operation or due to come online in Canada.

Green said the City of Hamilton was the first Ontario municipality to use its wastewater treatment facility to generate RNG. In 2006, it installed a 1.6-megawatt cogeneration unit at the Woodward plant to produce electricity and heat facility buildings.

Meanwhile, Surrey, B.C., has been processing the 65,000 tonnes of organic material it collects annually from residences and apartment buildings at a new facility that opened last spring. Harry Janda, Surrey's solid waste manager, said the city is using RNG to fuel its garbage trucks and is on target to reduce its carbon footprint by about 22,000 tonnes a year.

And then there's Stratford, Ont. It's embarking on a $15.5-million RNG project in partnership with its wastewater treatment plant operator, Ontario Clean Water Agency, which is set to open in 2020-21. Ed Dujlovic, Stratford's director of infrastructure and development services, said his city is in the final stages of inking a 20-year deal to sell RNG in Ontario to FortisBC Energy on the West Coast.

Dujlovic said as soon as the deal is done, it "gives the roadmap for everyone else."

Showwei Chu

Upcoming CBC series on climate change

In the coming weeks, CBC News will be doing special coverage on climate change in Canada. One thing we're looking for is people who would be willing to share stories, on camera, of what they're doing to meet the challenges of more unstable weather. If you'd be interested in being a part of this, let us know.

Email us at

Old issues of What on Earth? are here.

The Big Picture: Water consumption

Water is one of our most important resources, but not everyone has equal access to it. According to the advocacy group, more than 800 million people worldwide can't get safe drinking water and 2.3 billion don't have access to a toilet. But for many of the dwellers of this planet, particularly in the West, this is an invisible issue. Here's a look at the biggest users, per capita, of water in the world, according to 2016 figures.

Hot and bothered: Provocative ideas from around the web

  • The growing move to decarbonize the world economy is of increasing concern to oil and gas companies like Shell and Exxon Mobil. Know what else has them worried? The global push to drastically reduce plastic — much of which, of course, is made from petroleum.

  • Speaking of which … in a bid to dissuade visitors from buying water in disposable plastic bottles, Iceland's government has launched a tourism campaign touting the deliciousness of its tap water. The fact that it's "pure glacial water filtered through lava for thousands of years" certainly helps.

  • Since we started this newsletter last October, many of you have written in to express your ambivalence about air travel, given its rather large (and growing) carbon footprint. This essay in the New York Times captures that tension of wanting to see the world while knowing the environmental cost of doing so.


Fast fashion: Not a good look for the planet

(Jude Domski/Getty Images)

For everyday fashion shoppers, it is pivotal to stay on top of trends – for the right price, of course. But for the planet, it's a major sustainability issue.

In the last few decades, there has been a growing move toward "fast fashion," defined as inexpensive, trendy clothes that copy the latest catwalk designs and bring them to consumers through major retailers like H&M, Zara and Topshop.

According to the Ellen MacArthur Foundation, a non-profit organization that helps businesses become more sustainable, the fast fashion industry is worth 1.3 trillion US. But there are serious questions about how the clothes are made, how much we buy and how we dispose of it.

"Shopping will make you feel better — momentarily," said Anabel Maldonado, a fashion psychologist based in London, England. But there are risks to over-consumption.

A study in the journal Nature Climate Change said fast fashion has caused a spike in clothing consumption and waste over the last two decades. The consultancy McKinsey reports that consumers, on average, are buying 60 per cent more clothing textiles compared to 2000, but keeping clothes for only half as long.

Textile production primarily uses non-renewable resources, including oil, to create synthetic fibres, fertilizers to grow cotton and chemical colour dyes. It's not uncommon for fast fashion textiles to be made from blends of different fabrics, which makes recycling garments much more difficult. Not only that, the Ellen MacArthur Foundation reports that in 2015, the fashion industry produced 1.2 billion tonnes of greenhouse gases.

Maldonado said that because fast fashion is so cheap, it can lead to compulsive buying. And that doesn't bode well for the planet.

Fashion historian and designer James Fowler said consumers, on the whole, are not aware of the hidden costs. "The new generation has been given fast fashion, and they don't realize the end result is problematic," said Fowler. "We are hooked on the idea that we can go out and buy a T-shirt for eight dollars."

Major players in the fashion industry have begun making conscious efforts to be more green – Nike and Central Saint Martins, for example, created a sustainability manual for designers. It suggests using low-impact materials (limiting the use of toxic and hazardous chemicals), designing with recyclability in mind and minimizing manufacturing waste.

H&M and Zara have also launched sustainability initiatives. H&M named its sustainability line the Conscious Collection. Zara's parent company, Inditex, has an eco-label called Join Life.

Consumers obviously play a big role in the demand for fast fashion. Maldonado said the solution to over-buying cheap, environmentally unfriendly clothing is self-knowledge.

"The conscious consumer knows themselves," said Maldonado, and won't be tempted to "buy everything and every trend."

Kelsey Mohammed

Stay in touch!

Are there issues you'd like us to cover? Questions you want answered? Do you just want to share a kind word? We'd love to hear from you. Email us at

Sign up here to get What on Earth? in your inbox every Thursday.

Editor: Andre Mayer | Logo design: Sködt McNalty


To encourage thoughtful and respectful conversations, first and last names will appear with each submission to CBC/Radio-Canada's online communities (except in children and youth-oriented communities). Pseudonyms will no longer be permitted.

By submitting a comment, you accept that CBC has the right to reproduce and publish that comment in whole or in part, in any manner CBC chooses. Please note that CBC does not endorse the opinions expressed in comments. Comments on this story are moderated according to our Submission Guidelines. Comments are welcome while open. We reserve the right to close comments at any time.

Become a CBC Member

Join the conversation  Create account

Already have an account?