Unlocking synergy in thermophilic co-digestion of rice straw and food waste: boosting biogas production through accelerated kinetics and substrate biodegradability

This study investigated the mesophilic and thermophilic anaerobic digestion (AD) systems of rice straw (RS) (40 %-100 %) and food waste, comparing biogas production performance, organic matter degradation characteristics, and energy balance assessment. Results showed that thermophilic conditions exhibited excellent hydrolysis kinetics, and especially at 100 % RS ratio, with significantly higher biogas production rate and methane yield (154.1 vs. 94.5 mL/g total solids). However, both temperature regimes maintained biogas production stability, which may be attributed to the supply of non-ammonia alkalinity. Furthermore, energy balance assessment revealed that mesophilic conditions had higher energy recovery potential at 40 % RS ratio, while thermophilic systems achieved superior net energy output at higher RS ratio, as increased methane production offset additional heating requirements. This study reveals the key influence of temperature conditions on AD technology for lignocellulosic waste, providing a technical foundation for sustainable green agricultural development.