Environment, News, Science

Toronto to Turn Food Scraps into Biofuel

By Monique Conrod

A "closed loop" infographic that shows how organic waste goes from collection to anaerobic digestion to become fuel.

Waste collection trucks in Toronto, Ontario (in Canada) will soon be running on fuel made from some of the same food waste that they pick up at the curb each week.

People in Toronto put all of their organic waste (food scraps) into a special “green bin” to be collected by city trucks once a week and disposed of. Now the city is working on a plan to turn that food waste into a clean and renewable source of fuel.

Organic waste is taken to a special facility where it is put into large machines called “anaerobic digesters.” The digesters break the food waste down, (in the same way our bodies digest our food). That process creates solid waste and gas.

Usually, this gas is just burned off. But if all of the impurities (bad stuff that isn’t needed) are removed, the gas can be turned into a biofuel called renewable natural gas (RNG). That RNG can be used instead of the fossil fuels we use now – oil, coal and natural gas – as gas for cars and trucks or to heat people’s homes.

Using RNG instead of fossil fuel products will help keep Toronto’s air cleaner. It will also reduce the amount of harmful greenhouse gases the city produces. (Greenhouse gases trap heat in the Earth’s atmosphere and contribute to climate change.)

Fossil fuels give off greenhouse gases when they are taken out of the ground, and processed. They give off even more greenhouse gases when we burn them to heat our homes or fuel our cars.

RNG gives off lower amounts of greenhouse gases when it is being made and also when it is being used as fuel.

Using food waste to make RNG also helps keep it out of the landfills where regular garbage is dumped. If food waste is left to rot in landfills, it produces greenhouse gases.

RNG costs less to make than fossil fuel products because it is made from food waste that cities are already collecting each week. And, since there is a steady supply of organic waste from homes, restaurants and farms, RNG is a “renewable” energy source. (In this case, “renewable” means it is replaced naturally as we use it, and won’t run out.)

Toronto hopes to begin producing RNG from organic waste by March 2020. Then it will use the gas to fuel the city’s waste collection trucks.

The city is working on the project with Enbridge Gas Inc., a company that produces and sells fossil fuel-based natural gas. When RNG becomes available, Enbridge will use RNG along with fossil fuel-based natural gas to heat homes in the city.

Toronto hopes to have four facilities that can convert food waste to RNG. That will reduce the amount of greenhouse gas the city produces by about the same amount as taking 35,000 cars off the road.

Closing the Loop

Producing renewable natural gas from household food waste is part of a “closed-loop” or “circular” process.

Many of the things we use every day are part of linear (straight line) process. Items are made, bought, used and thrown away. This uses up a lot of resources, and creates a lot of waste.

In a circular  or closed-loop process, items are made, bought, used, then taken apart and remade into something else.

For example, when we recycle paper, it can be made into new paper products such as notebooks, egg cartons, or coffee filters. Often, these products can also be recycled or composted when we’re finished with them.

Recycling paper means fewer trees are cut down to make new paper. It also costs less and uses less energy than making new paper. And it reduces the amount of  waste we produce.

With RNG, food waste from our homes is picked up by collection trucks, processed, and turned into a product that generates heat and electricity for the homes we live in, and provides fuel for the same trucks that collect the food waste.


The City of Toronto is trying something new, to combat climate change. Do you think it will work? Why or why not? (Or: how big an effect do you think the program will have?)

Have you ever thought of something to help make the world more environmentally friendly? What are your ideas? What are some things that would have to happen, to put your plan in place?

This article is about a program in Toronto, Ontario in Canada. What is your city or town doing to help people reduce, recycle and reuse or to combat climate change?

A “sidebar” is a (usually smaller) article that gives a bit more information about a topic. This sidebar explains the “closed-loop” process. Pretend you met someone who didn’t know anything about recycling. Create (or say) a sidebar about any of these topics from the main article: sustainable energy; RNG; fossil fuels; greenhouse gases; organic waste; digestion; green bins.


Toronto’s “Waste Wizard” makes it easy to know what can and cannot be recycled by the city: https://www.toronto.ca/services-payments/recycling-organics-garbage/waste-wizard/

The City of Toronto (like most big cities) has a website that lists what can and cannot be recycled or put in their green bins: https://www.toronto.ca/services-payments/recycling-organics-garbage/houses/what-goes-in-my-green-bin/