Abstract:

To explore the difference in nutrient loss between aerobic and anaerobic fermentation of solid-liquid integrated slurry, an experiment was conducted to compare these two fermentation processes. The study analyzed the changes of physicochemical indexes such as pH, electrical conductance (EC), chemical oxygen demand (COD), biochemical oxygen demand (BOD₅) and nitrogen indexes during fermentation process, and the maturity of pig slurry was evaluated by germination index (GI). The results showed that both aerobic and anaerobic fermentation significantly influenced the physicochemical properties and organic matter decomposition of pig slurry. Pig slurry of aerobic fermentation reached maturity standards (GI≥70%) after about 15 days, but suffered a high nutrient loss of 31.8%. Pig slurry of anaerobic fermentation reached maturity standards after about 45 days with minimal nitrogen loss (<5.6%). At 45 days, BOD₅ and COD decreased by over 70% in aerobic fermentation, while they decreased by 33.7% and 39.6% respectively in anaerobic fermentation. In conclusion, anaerobic fermentation was recommended for treating solid-liquid integrated slurry in Northeast China. When determining the application amount, the fermentation time and maturity of the pig slurry should be taken into account to maximize resource utilization.

Key words: pig slurry, nitrogen, aerobic fermentation, anaerobic fermentation, germination index