Biogas potential assessment and characterization of Korean slaughterhouse waste for anaerobic digestion

Abstract

The global slaughterhouse waste (SHW) generation is rapidly soaring due to expanding population and shifts in eating pattern. Anaerobic digestion (AD) enables a sustainable and cost-efficient treatment of SHW through biological conversion of the organics into biogas. To assess the feasibility and provide basics for planning, this study investigated the characteristics of the SHW in a year basis for a thorough set of parameters including the organic compositions and the CH4 production potential. The organic wastes could be categorized as the red (heart, lung and liver) and the white (large intestine) SHWs. The white SHW had a higher lipid content (average 22.4%, wet basis) as well as the solids, resulting in the CH4 potential of 684.8 mL/g VS which was approximately 1.4-fold that of the red SHW (483.6 mL/g VS). The low C/N ratio (7.1) of the red SHW due to the high protein content (14.5%, wet basis) could lead to ammonia inhibition if this waste is solely treated. Next-generation sequencing was analyzed to depict the microbial community and the importance of initial inoculum selection could be highlighted. The community structure greatly affected the lag phase of the biological process ranging 0.26–1.28 d for the red SHW and 0.35–3.08 d for the white SHW. The energy potential of SHW AD in Korea was estimated to be 10920 TOE/yr, which is as high as 14.5% of the domestic biogas energy production in 2019. Overall, the SHW can be considered as energy-intensive feedstock for AD, and co-digestion with other wastes such as food waste or waste sludge could be recommended.