Trash or Treasure? Food scraps could replace fossil fuels, research suggests

Engineers at the University of Waterloo say they've found a way to transform table scraps into a replacement for fossil fuels, providing clean energy and an alternative to petrochemical plastics.

The technology harnesses the food's natural fermentation process. The result is a biodegradable chemical that can be refined and transformed.

The work started five years ago, when Hyung-Sool Lee, director of the Waterloo Environmental Biotechnology Lab, started noticing cities and states in the U.S. getting creative with their food waste.

"Canada, we still put a lot of organic waste in landfill sites," said Lee, a civil and environmental engineering professor.

He started to dig into the existing research and was shocked to learn how bad the situation had become.

"Canada is one of the top food waste producers in the world. About 400 kilograms of food waste per capita a year — half a tonne of food waste."

Two-thirds of food waste still edible

Researchers estimate as much as 58 per cent of all the food in Canada goes to waste each year, totalling $49.5 billion.  

At the household level, about 4.5 kilograms of food can end up in the garbage each week, according to University of Guelph professor Kate Parizeau.

"We live in a culture that's very consumption oriented," said Parizeau, one of the researchers behind the Guelph Food Waste Research Project. Almost two thirds of the food people throw out — in the garbage or compost bin — is still edible.

"We find for example full heads of lettuce, that even after they're sitting in the green bin for a day or two still look like they could be washed off and put onto a plate."

Parizeau adds that waste isn't just a problem in the household. It happens all across the food system, from production to retail.

She says reducing the amount of food that ends up in the garbage should be the priority, but innovations that reuse waste are another important part of the solution.

Lee's technology is still in the early stages. In his lab at the University of Waterloo, food scraps including fruits, vegetables and noodles are loaded into a basket and placed inside a 70 centimetre long tube called a reactor.

Water and a cocktail of microorganisms and nutrients trickle through the waste and collect at the bottom of the tube, explained research assistant Swakshar Saha.

That liquid, said Saha, is a soup of volatile fatty acids, alcohols — and most importantly — a chemical called carboxylate.

Carboxylate is chemical byproduct that can be used in place of a number of petroleum products, said Lee.

"We can synthesize plastic material, or we can synthesize transportation fuel — such as butanol or ethanol," he said.

More affordable for small, medium cities

The idea of harnessing food waste as a source of energy isn't new.

Many large cities will use a process called anerobic digestion, which involves vigorously mixing the waste with water in large holding tanks to produce methane gas. The gas is then burned for electricity and used to heat and power homes.

But the existing technology is expensive and out of reach for many small and medium-sized cities.

Lee said his system seems to be cheaper and is actually in reach of municipalities without the population base of Vancouver or Toronto.

"They rely on a high population. But in reality, when we look at just Canada we have tons of small cities: 10,000 population or 5,000 population," he said.

And the more municipalities that get on board, the better it is for everyone. Compost can be dealt with in the community in which it's created, instead of being handled by centralized facilities — cutting down on the fossil fuels needed to transport food waste across long distances.

Lee hopes his technology will be on the market within the next five years.