Enhancement on methane production and anaerobic digestion stability via co-digestion of microwave-Ca(OH)_2 pretreated sugarcane rind slurry and kitchen waste

摘要

To verify the practicability of biogas production from liquid waste emanated from alkaline pretreatment of lignocellulose, the blended solid-liquid slurry of sugarcane rind (SR), which generated from Ca(OH)(2) coupled microwave pretreatment and undergone decalcification via biogas bubbling, was anerobically co-digested with kitchen waste (KW) in batched mesophilic assays at five mixing ratios. Results showed that the pretreatment improved the cell-free enzyme activity (CFEA) on cellulose hydrolysis during the anaerobic co-digestion (AcoD). The strategy of AcoD of pretreated SR slurry (PSRS) or SR with KW not only increased methane production but also was benifical to the process stability. The synergistic effect was revealed based on methane production, alkalinity and enzyme activities in AcoD process. The 25% PSRS +75% KW demostrated the highest methane production of 430.4 N mL CH4/g volatile solids, which was 22% and 86% higher than 25% SR + 75% KW and 100% SR, respectively. The higher the proportion of PSRS or SR in feedstock, the higher the CFEA on cellulose hydrolysis revealed during fermentation. The maximum CFEA on cellulose hydrolysis of 0.293 U/g appeared on the 14th day in 100% PSR, which was 24.2% higher than that of 100% SR. The results will provide a reference for utilizing SR and KW in actual biogas plant. (C) 2020 Elsevier Ltd. All rights reserved.