Biochar helps cut manure emissions

Researchers find that adding charcoal-like carbon and ash to composting manure can reduce odours as well as methane

Researchers have found that adding a small amount of biochar during the composting process for manure from dairy cattle can cut methane emissions by 84 percent.

Minimizing the greenhouse gases behind climate change is sometimes seen as a problem that requires expensive high-tech solutions, said Gerardo Diaz, professor of mechanical engineering at the University of California, Merced.

“And if this can (instead) be done with materials that are already available, are cheap to make and in a certain way, you’re using waste — that is, the biomass — then, why not? It’s kind of like a no brainer.”

Biochar is the charcoal-like carbon and ash left over when biomasses such as crop residues are heated using pyrolysis under conditions of low oxygen. A study by researchers at the university found that adding as little as six percent biochar to dairy manure resulted in an 84 percent reduction of methane during composting.