Published at 8:42
Pollution and odor
An excellent phosphorus-rich fertilizer, slurry is nevertheless a major source of pollution due to methane emissions during storage and soil leaching, which can lead to accidental release into waterways. Research on finding solutions is not new, and several methods are available, but none of them has so far been unanimously accepted.
Luc Roy, 80, has led the Régie de l’Assurance Agricole, formerly Financière Agricole, during his career. 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 industry and these issues,” he explains. After completing three projects, he contacted the Institute for Research and Development in Agroecology (IRDA), with whom he joined this adventure. “I saw a technique in Belgium that handles manure naturally, and that inspired me. »
Oxygen for modification of microbial flora
Therefore, from 2015 to 2022, IRDA conducted a series of tests before arriving at a process that eliminates 99.9% coli and reduce odor and greenhouse gas (GHG) emissions by 95% compared to raw slurry storage. “We use a two-stage aerobic pig manure treatment process. The raw sludge is first mixed and recycled in the tank, introducing oxygen into it. The pump then feeds everything to the BIO-RHO2 bioreactor. Again, air is forced into it by perforated pipes. It is the presence of oxygen that promotes the growth of bacteria that decompose organic matter and repair manure defects,” explains Patrick Brassard, IRDA project leader and successor to principal investigator Stéphane Godbout.
A more complex solution than it seems
Blowing air may seem easy at first, but the researcher explains that it’s harder than it looks due to the depth of the holes (three meters) and the amount of energy needed to blow the air. The method overcomes this problem. “Everything has to be set: the pump power, the amount of material and the amount of air per cubic meter. If we don’t do it right, we’ll end up with slurry that foams and overflows. »
Possible income for agricultural producers
After a few days, the treated slurry naturally separates into two phases and forms fertilizer. They can become a source of income for growers who can sell it as a fertilizer. The next step for IRDA will be to organize a technology show next fall. If funding is available, the marketing phase is planned for 2023. For his part, Luke Roy sees far. He believes that aerobic treatment can add value to any production manure. “This is a simple technology that can be fully assembled on a farm in a simple container. This is a win-win solution for a grower that significantly reduces the ecological footprint of their breeding while increasing their profits. »