Relationship between anaerobic digestion characteristics and biogas production under composting pretreatment

To contribute to a better understanding of the relationship between the digestion characteristics and biogas production after composting pretreatment (CP), path analysis was used to analyze the response relationship between substrate and total biogas production (TBP), factor analysis was used to analyze the relationship between the factors in anaerobic digestion (AD) and daily biogas production (DBP). Results showed that pretreatment at 35 °C for 6 days (T35d6) produced a maximum TBP (285.80 mL/kg TS). There were direct influences and indirect influences of substrate characteristics on TBP. C/N was the key factor that affects TBP, and it does this affects TBP by the changing of cellulose content. The influence of the factors affecting DBP varied in relation to differences in the digestion process. After CP of T35d6, the volatile fatty acid (VFA) content and pH had the most influence on DBP on days 5, 10 and 15. Reducing sugar content had the most influence on days 0, 20, 25, 30, and 35. CP improved the TBP by changing the relationship between the substrate characteristics and TBP, as well as the relationship between the characteristics of the AD process and DBP. The pretreatment made the environment more suitable for AD.