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Intermittent-vacuum assisted thermophilic co-digestion of corn stover and liquid swine manure: Salinity inhibition

Zhang, Renchuan, Anderson, Erik, Chen, Paul, Addy, Min, Cheng, Yanling, Wang, Lu, Liu, Yuhuan, Ruan, Roger
Bioresource technology 2019 v.271 pp. 16-23
ammonia, anaerobic digestion, butyrates, carbon nitrogen ratio, corn stover, liquids, methane, methane production, pig manure, salinity
In this study, the effects of Intermittent-Vacuum Stripping (IVS) on activities of methanogenesis in co-digestion of corn stover with liquid swine manure (LSM + CS) under thermophilic anaerobic digestion (TAD) conditions were evaluated. A 65% methanogenesis activity inhibition was observed in pretreated LSM plus corn stover (pLSM + CS), while 60 and 165 mL/L/day CH4 productions were achieved in pLSM + CS and LSM + CS, respectively. The high salinity condition (5.28%) after IVS pretreatment was considered the primary inhibitor in pLSM + CS, while the ammonia (≤600 mg/L), C:N ratio (15.52) and volatile solid loading rate (3 g/kg−1·day−1) didn’t show a negative effect on CH4 production. When salinities were increased from 2% to 4% and 8%, 50% and 100% inhibition were observed respectively. The butyrate accumulation was a potential indicator of the non-salinity-inhibition status for methanogenesis in TAD.