AUDIO: Patrick Serfass from the American Biogas Council discusses digestate as a fertilizer source with Brownfield’s Larry Lee.
The leader of the American Biogas Council says digestate from anaerobic digesters is a great source of crop nutrients.
Patrick Serfass with the American Biogas Council says, “All of the nitrogen, phosphorus, and potassium, all of that N,P, and K that we all need is in our waste if we can just extract it.”
Serfass tells Brownfield that digestate from anaerobic digesters can’t replace all the commercial fertilizer, but it can make a significant contribution to farm nutrient needs. “We’re talking millions of tons of organic waste that can be recycled, and of that, you end up with millions of tons of fertilizer, so it’s a huge amount.”
Serfass says the organic waste from digesters is a domestic, concentrated nutrient source that can help alleviate the cost and availability problems with commercial fertilizer. He says having more digesters also puts the supply of digestate closer to the demand. “There are people and animals everywhere. Most importantly, where there are people and animals, that’s normally where the fertilizer is needed, so it’s distributed all around the country where it’s needed. It’s just a matter of us utilizing it.”
Serfass says more biogas systems should be built to utilize the nutrients and the methane produced by digesters. Right now, he says there are 26-hundred biogas systems in the U.S. with at least one in every state, but that’s less than 15% of the potential market.
