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An innovative intermittent-vacuum assisted thermophilic anaerobic digestion process for effective animal manure utilization and treatment

Zhang, Renchuan, Anderson, Erik, Addy, Min, Deng, Xiangyuan, Kabir, Fayal, Lu, Qian, Ma, Yiwei, Cheng, Yanling, Liu, Yuhuan, Chen, Paul, Ruan, Roger
Bioresource technology 2017 v.244 pp. 1073-1080
algae culture, ammonia, ammonium sulfate, anaerobic digestion, biogas, hydrogen sulfide, hydrolysis, hydroponics, methane production, nitrogen, nitrogen content, pH, pig manure
Intermittent-vacuum stripping (IVS) was developed as a pretreatment for thermophilic anaerobic digestion (TAD) to improve methanogenesis and hydrolysis activity through preventing free ammonia and hydrogen sulfide (H2S) inhibition from liquid swine manure (LSM). Over 98% of ammonia and 38% organic nitrogen were removed in 60min from 55°C to 85°C with vacuum pressure (from 100.63±3.79mmHg to 360.91±7.39mmHg) at initial pH 10.0 by IVS. Thermophilic methanogenesis and hydrolysis activity of pretreated LSM increased 52.25% (from 11.56±1.75% to 17.60±0.49%) in 25days and 40% (from 10days to 6days) in bio-methane potential assay. Over 80% H2S and total nitrogen were removed by IVS assistance, while around 70% nitrogen was recycled as ammonium sulfate. Therefore, IVS-TAD combination could be an effective strategy to improve TAD efficiency, whose elution is more easily utilized in algae cultivation and/or hydroponic system.