Though there lays a lot of potential in the reuse of cow manure components, to get there, a serious treatment is required. Solids and insoluble phosphorus pose a challenge yet to be solved, but scientists in the soil theme have found a way to increase hydrolysis and methanization.
When digesting cow manure in up-flow anaerobic sludge blanket reactors for 456 days, calcium addition resulted in improved hydrolysis (29% to 67%) and methanization (a near two-and-a-half times increase with Ca). Even compared to commercial practices, the methane production was improved by 30%. All the while, the phosphate remained in struvite crystals, but could be removed better with calcium addition (38 to 61%).
Schott, Chris, Jorge Ricardo Cunha, Renata D. van der Weijden, and Cees Buisman. 2023. “Innovation in Valorization of Cow Manure: Higher Hydrolysis, Methane Production and Increased Phosphorus Retention Using UASB Technology.” Chemical Engineering Journal (Lausanne, Switzerland: 1996) 454 (140294): 140294. https://doi.org/10.1016/j.cej.2022.140294.