Evaluation of biogas production and pollutant removal efficiency of two-phase anaerobic digestion treating slaughterhouse effluent

Treatment of slaughterhouse and other agro-processing industry effluent has become important due to continuous global population growth and meat demand, particularly in developing countries, for sustainable biowaste management as well as value additions such as biofuel. Therefore, the objective of the study was to evaluate the performance of two-phase anaerobic digestion of slaughterhouse wastewater in terms of biogas production, methane yield, and removal efficiencies of organic matter, total nitrogen, and total phosphorus. Two consecutively connected 40 L galvanized metal anaerobic batch bioreactors were used to conduct the experiment. The total phosphorus removal efficiencies of hydrolytic-acidogenic reactor and methanogenic reactor were 13.34% and 16.58%, respectively. Total chemical oxygen demand, soluble chemical oxygen demand, biological oxygen demand, total dissolved solids, total solids, total suspended solids, volatile solids, and turbidity had overall removal efficiencies of 82.87, 88.53, 93.32, 75.35, 95.55, 98.95, 97.42 and 98.06%, respectively. Biogas production of 189.45 mL/day with methane and carbon dioxide compositions of 67.69% and 29.9%, respectively, was also achieved. It was concluded that the two-phase anaerobic digestion of slaughterhouse wastewater shows substantial organic matter removal efficiencies and biogas production.