Agri-food technologies | A solution to counter pig manure odors?

Some 2,000 breeders and 8 million animals a year, that’s the portrait of pork production in the province, the second largest agri-food sector. So many pigs means millions of tons of slurry and the odors that come with it… Biorecovery may be the new solution.

Posted at 8:42

Julie Roy
special collaboration

Pollution and smell

An excellent fertilizer rich in phosphorus, slurry is nonetheless a major source of pollution due to methane emissions during storage and soil leaching which can cause accidental spillage into waterways. Research to find solutions is not new and several techniques are available, but none to date has been unanimously accepted.

A retirement plan

80 years old, Luc Roy was during his career at the head of the Régie de l’assurance agricole, the former Financière agricole. Armed with his managerial experience, he was convinced that if we didn’t solve the pig manure problem, the very future of production was at stake. When I retired, I wanted to do something useful for this sector and these issues,” he explains. After carrying out three projects, he contacted the Institute for Research and Development in Agro-Environment (IRDA), with whom he joined in this adventure. “I had seen a technique in Belgium that treated slurry in a natural way, and that’s what inspired me. »

Oxygen to modify the microbial flora

From 2015 to 2022, IRDA therefore carried out a range of tests before arriving at a process that eliminates 99.9% of E.coli and reduce odor and greenhouse gas (GHG) emissions by up to 95% compared to emissions from raw manure storage. “We use a two-step aerobic treatment process for pig manure. The raw slurry is first agitated and recirculated in a tank by injecting it with oxygen. Then, a pump brings everything into the BIO-RHO2 bioreactor. Again, air is pushed into it with perforated pipes. It is the presence of oxygen that allows the growth of bacteria that will degrade organic matter and eliminate manure defects,” explains Patrick Brassard, project manager at IRDA and successor to principal researcher, Stéphane Godbout.

A more complicated solution than it seems

Injecting air may seem simple at first, but the researcher explains that it is more complex than it seems due to the depth of the pits (three meters) and the amount of energy required to inject air. The method overcomes this problem. “Everything has to be configured: the power of the pump, the quantity of material and the quantity of air per cubic metre. If we don’t do things correctly, we end up with liquid manure that foams and overflows. »

Possible income for agricultural producers


PHOTO PROVIDED BY IRDA

The equipment needed for the process comes in a simple container, which can be placed on the farm directly.

After a few days, the treated slurry separates naturally by settling into two phases and produces fertilizers. These can become a source of income for producers who can sell it as fertilizer. For IRDA, the next step is to set up a technology showcase next fall. If the financing is there, a marketing phase is planned for 2023. For his part, Luc Roy sees far. He believes that aerobic treatment could add value to animal manure from any production. “It’s a simple technology that can be assembled entirely on the farm in a simple container. It is a winning solution for the producer who substantially reduces the ecological footprint of his breeding while increasing his profitability. »

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