Co-digestion of abattoir effluent and rumen content for waste management and biogas production – A case study

This study examined the feasibility of utilizing two primary waste types from a local abattoir for waste management and subsequent biogas production. In the study, wastewater (WW) and rumen content (RC) found at a red meat abattoir were used as substrates during anaerobic digestion (AD). An automated methane potential test system (AMPTS III) was employed to digest the substrates at different doses at 37°C. The raw WW exhibited a chemical oxygen demand (COD) of 74 g/l, indicating excessively high levels. Following anaerobic digestion, the maximum COD removal was observed at a ratio of 70:30 (RC:WW), achieving a removal rate of 70.3%, a COD of 19.3 g/l. The production of biogas was attributed to high RC loadings, wherein a cumulative biogas production of 1791 Nml/gCOD_removed was produced over 24 days, while biomethane and carbon dioxide production was 491.1Nml/gCOD_removed and 1299.9 Nml/gCOD_removed over the same period. The study indicated that the inclusion of RC reduced the rate of pH decline in the digester, suggesting its viability as a material for anaerobic digestion. Typically, mono-digestion of the abattoir WW yields biomethane with a purity of up to 96.96%, whilst mono-digestion of RC yields high amounts of carbon dioxide