Cold-loving bacteria turns food waste into energy and fertilizer

Canada’s frigid winters have always limited 
using natural processes to convert waste

Over 1.3 billion tonnes of food waste are created globally each year. A new process promises to make converting it to fertilizer and fuel more efficient in cold climates.

Researchers from Montreal’s Concordia University say they’ve found a way to process waste into resources in colder climes.

They’re using cold-tolerant bacteria to fuel the process.

In a study published in the journal Process Safety and Environmental Protection, authors Rajinikanth Rajagopal, David Bellavance and Mohammad Saifur Rahaman demonstrate the viability of using anaerobic digestion in a low-temperature (20 C) environment to convert solid food waste into renewable energy and organic fertilizer.

They employed the bacteria to break down food waste in a specially designed bioreactor, producing a methane yield comparable to that of more energy-intensive anaerobic digestion processes.

“There is enormous potential here to reduce the amount of fuel that we use for solid waste treatment,” Rahaman said.

“Managing and treating food waste is a global challenge, particularly for cold countries like Canada where the temperature often falls below -20 C and energy demands related to heating are high.”

He also said the most commonly used forms of anaerobic digestion require large amounts of energy to heat the bioreactors and maintain temperatures for the bacteria’s optimal performance.

“What we’ve learned is that we can now use adapted psychrophilic bacteria to produce a level of methane comparable to those more common forms, while using less energy.”

Globally, more than 1.3 billion tonnes of municipal waste are created each year, and that number is expected to increase to 2.2 billion by 2025. Most of it ends up in landfills where it biodegrades over time, producing a powerful greenhouse gas.

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