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摘要
Ammonia inhibition is regarded as a main factor that influences the popularization and application of high solid anaerobic digestion. In this study, batch experiments were carried out with exogenous ammonia addition to investigate the effect of ammonia concentration on methane production and methanogenic community during the anaerobic digestion of swine manure. Results showed that the daily and cumulative methane production both decreased obviously when the addition amount was 2 000 mg?L-1 with corresponding TAN about 3 596.7 mg?L-1. Furthermore, extend of ammonia inhibition was further aggravated with the accumulation of VFAs, lag phase of methane production peak and failure of propionic aid degradation when the addition amount of ammonia exceeded 4 000 mg?L-1 with corresponding TAN about 5 618.7 mg?L-1. With the increase of ammonia addition, the methane production of volatile solid in swine manure was (369.0 ± 17.3), (318.5 ± 7.6), (234.7 ± 2.5) and (165.4 ± 19.4) mL?g-1, respectively, resulting in 14%, 38% and 55% reduction of methane production potential compared with control group. The methanogenic community changed significantly when the addition amount exceeded 4 000 mg?L-1. For example, Methanosaeta was outcompeted by Methanosarcina among aceticlastic methanogens, and Methanospirillum was eliminated by Methanoculleus and Methanomassiliicoccus among hydrogenotrophic methanogens, indicating that the latter ones are more tolerant to ammonia. According to the result of PCA and RDA, high concentration of ammonia nitrogen would promote the evolution of methanogenesis from the aceticlastic pathway to hydrogenotrophic pathway gradually.
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单位环境模拟与污染控制国家重点实验室; 中国科学院大学
