Bringing Food Waste Full Circle

Australians send more than 7 million tonnes of food waste to landfill annually, where it produces greenhouse gas emissions including methane, which is much more harmful than carbon dioxide. Every year, the methane generated from food waste is estimated to have a warming effect equivalent to more than 20 million tonnes of CO2. While there have been efforts to convert food waste to energy through composting, it has been challenging to find ways to reuse the waste at scale. 

Dr Dharma Hagare, a senior lecturer in sustainability engineering who leads the Nutrient, Energy, Water and Materials Recycling Group at Western Sydney University, has been investigating various ways that food waste could be ‘upcycled’ on a large scale. 

"We have been working on the circular economy of water, food and nutrients by recycling the majority of food waste as animal feed," explains Hagare. "This would not only eliminate the production of greenhouse gas emissions from waste, but also save the raw food material that would otherwise be used to produce animal feed."

Over the past few years, Hagare’s team has carried out proof-of-concept studies that have demonstrated the feasibility of producing chicken feed from food waste collected predominantly from restaurants, grocers and fish markets at the Sydney Markets, in Flemington. 

"The production of animal feed and liquid fertiliser from food waste has not been attempted before. We have developed a unique process where all the food waste is recycled with zero waste produced," he says. 

The upcycling process involves a series of steps including sorting, heating, mincing, drying, grinding, and pelletising to produce animal feed. Liquid extraction is also required to make the fertiliser. The resultant chicken feed is of similar nutritional value to commercial products, and the liquid fertiliser has similar concentrations to that of commercial liquid fertiliser used in hydroponics.

Through a new start-up, Food Recycle International, the team is analysing the economic and life cycle considerations of this food waste recycling approach. 

"The research is now at the commercialisation stage," says Hagare. The industry partner, Food Recycle Ltd, has partnered with OzHarvest Ventures to raise $18 million to start commercial production in Sydney. The research team is now testing diverse commercial food waste streams from across the country. "Research and development never ends," says Norm Boyle, CEO-Founder of Food Recycle Ltd. "The company is very grateful for the collaboration with WSU and expects it to continue for many years to come."

Although there remain many aspects of the technology to work through, including the economies of scale and life cycle costing, as well as biosafety and nutrient content, its potential as an enabler of the circular economy is huge. The cost to the economy of food waste disposal in Australia alone amounts to more than $30 billion dollars each year. 

"Upcycling and energy generation from food and other organic waste will be a top priority for all advanced economies," adds Hagare. "There will be significant investment in new methods and technologies for recycling these materials. Our work is peaking at the right time to harness these investments."

His team is also looking at other organic waste streams. Food waste constitutes just half of the 15 million tonnes of organic waste generated in Australia each year. The team is working on processes to convert organic waste into raw material for brick production, and has partnered with Global Renewables, Austral Bricks, and Circular Australia to trial the technology. The possibility of producing bioleather and biofibre is also being explored with another industry partner.  

"The projects we are working on will eventually reduce the organic waste going to landfill," Hagare says. "If we can reach even a 50% reduction in the organic waste going into landfill, it will be a great achievement."