Energy recovery from the anaerobic co-digestion of ricotta cheese whey and dairy cattle manure.

SANTANA, L. A. R.; SILVA, G. H. da; CARNEIRO, J. da C.; MOTTA, I. G. B. da; MENDONÇA, H. V. de; OTENIO, M. H.

Energy recovery from the anaerobic co-digestion of ricotta cheese whey and dairy cattle manure.

Autores

Descripción

This study evaluated biogas production, methane concentration and yield, as well as the potential for energy production of anaerobic co-digestion of ricotta cheese whey and dairy cattle manure in 60 L plug flow reactors. Four reactors were operated: three with different proportions of ricotta cheese whey (20, 40, and 80%) and a control reactor containing only dairy cattle manure. The reactors were operated for 106 days, with a hydraulic retention time of 30 days. In all reactors, pH remained near neutrality, and alkalinity stayed above 2,500 mg L⁻¹. Notably, only the reactor with 80% ricotta cheese whey demonstrated more efficient removal of total solids, volatile solids, biochemical oxygen demand, and chemical oxygen demand, with average reductions of 54, 69, 69, and 78%, respectively. However, the reactor operated with 40% ricotta cheese whey produced the highest accumulated biogas volume, surpassing the 80% ricotta cheese whey reactor by 36 L, with a realistic extrapolation of electricity production estimated at 1.67 kWh m- ³. Although methane yields were close to theoretical maximum values and methane concentrations showed no significant differences between treatments, the results confirm the effectiveness of anaerobic co-digestion in the treating of agro-industrial waste. The 40% ricotta cheese whey and 60% dairy cattle manure ratio stands as a promising alternative for biogas production.