Taking food full circle
What if, with a simple trip to a green bin, you could contribute to carbon reduction?
The possibilities of turning organic waste into useable products are being explored by Ryerson University molecular sciences master’s student Vanessa Bairos and her supervisor, chemistry professor Bryan Koivisto. A recent Government of Canada report, Taking stock: Reducing food loss and waste in Canada, estimated that 20 per cent of all food produced in Canada annually ends up as avoidable food loss, heading to landfills, incinerators or organic waste programs.
The Ryerson research was tackled through two separate industry-partnered projects. One is with CCI BioEnergy; the other is with Bio-Techfar Inc.
CCI BioEnergy, which was tasked with exploring solutions to the problem highlighted in the Government of Canada report, handles the City of Toronto’s organic waste using an anaerobic digestion process. As part of this process, there is a recoverable digestate material. The Ryerson team was asked to research if that by-product could be used as a fertilizer, as well as understanding the viability of smaller commercial units that could be installed in remote areas, such as apple orchards.
The testing conducted showed that the solid by-product, put straight onto the land, would not be an effective fertilizer due to high levels of potassium, says professor Koivisto. The potential of a synergy between the CCI BioEnergy project and the project with Bio-Techfar Inc., however, was spotted by the researchers.
The partnership with Bio-Techfar Inc. gave the researchers access to one of the company’s pyrolizer prototypes. The pyrolizer enables the process of pyrolysis, which is heating up material without oxygen and removing the water from the material at an atomic level. They had the idea to use the pyrolysis process on the solid by-products of the anaerobic digestion from the CCI BioEnergy projects, creating potentially useful materials.
They’ve found that putting that solid waste through the pyrolysis process produces biochar and biofuel, and other carbon allotropes. Carbon allotropes are comprised of the same element but it exists in two or more different forms.
“By combining these two processes, we were able to turn our compost into a by-product that shows evidence of graphite. It’s remarkable to see everyday waste reshaped by conversion to produce by-products that can create a circular economy and close the loop,” said Bairos.
In agriculture, the watered digestate could be recycled back in the greenhouse, while biochar can be added as a soil amendment. Professor Koivisto says potential applications could benefit the agriculture sector, the cannabis industry and perhaps the forestry industry.
“This could be used to revolutionize the cannabis industry where you have these closed loops, where you have to destroy your crop, you have to burn it,” said professor Koivisto. “This sort of closes the loop on a lot of things in the food, water, agriculture space.”
They continue to research the potential uses of carbon allotropes that are produced. Uses could range between a variety of materials, from graphene to biosensors. At worst, professor Koivisto says the allotropes could be added to concrete, increasing the concrete’s strength while trapping carbon for hundreds of years. “There are wins to be had even in the worst-case scenario from this research,” he said.
Both industry partners are interested in further relationships and, with a second-generation pyrolysis unit being developed by Bio-Techfar Inc., the researchers are exploring funding options for the next phase of the project. Bairos says that in the future, food waste could become part of the technological devices used daily.
“It could be created by something that you threw out the day before,” she said.
Funding and support for these projects has been provided by the Natural Sciences and Engineering Research Council of Canada, the Ontario Centres of Excellence, CCI BioEnergy, Bio-Techfar Inc. and Ryerson University’s Science Discovery Zone.