Abstract:This study utilized a CSTR reactor to anaerobically digest slaughter wastewater containing trace elements under medium temperature conditions, in order to monitor the quantity, quality, and process stability of biogas. Compared with the recommendations given in the literature, the determination of trace element contents of iron, nickel, cobalt, manganese, and molybdenum shows deficiencies. Adding these trace elements can improve degradation efficiency, increase biogas production, and enhance process stability. Compared with a steamer, the organic load rate is higher and the hydraulic retention time is lower. At an organic loading rate of 1.82 g/(L * d), the critical cumulative amount of volatile fatty acids in the control group was higher than 2.36 g/(L * d) in the digester with added trace elements. In the later weeks of the experiment, the stability of the process was significantly improved, and compared to reactors containing trace elements, the daily production of biogas in the reactor was reduced by 84%.