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为了探讨重金属Cu、Zn对有机废弃物产甲烷的影响机制,研究了在55℃条件下添加外源Cu、Zn对猪粪和玉米秸秆质量比为2∶1混合物料厌氧发酵过程产甲烷特性的影响.结果表明:当厌氧发酵液的NH_4~+-N含量低于706.7 mg·L-1时对厌氧发酵未产生明显的抑制作用.厌氧发酵液中的VFA下降幅度与累积甲烷产生量呈正相关.随着混合物料中Cu、Zn浓度的增加,累积产甲烷量总体上均呈现降低趋势(除Zn100处理外),当Cu<413.7 mg·kg-1或Zn<500.6 mg·kg-1时,对厌氧发酵的影响不明显,当Cu>513.7 mg·kg-1、Zn>600.6 mg·kg-1时,对厌氧发酵产生显著的抑制作用,且Cu对厌氧发酵的抑制作用强于Zn.不同浓度Cu、Zn与发酵料液中纤维素酶、蔗糖酶和脲酶活性均呈显著负相关(p≤0.05),Cu处理发酵料液中纤维素酶、蔗糖酶和脲酶活性与累积产甲烷量均呈显著正相关(p≤0.05);Zn处理的纤维素酶活性和蔗糖酶活性与其呈显著正相关(p≤0.05),但脲酶活性与其相关性不显著.表明Cu、Zn可能通过影响酶活性而对厌氧发酵过程和累积甲烷产生量产生影响.
In order to investigate the mechanism of heavy metal Cu and Zn on the methane production of organic wastes, the effects of adding exogenous Cu and Zn on methanogenic properties in anaerobic fermentation of 2: 1 mixture of pig manure and corn stover at 55 ℃ were studied .The results showed that when the concentration of NH_4 ~ + -N in the anaerobic fermentation broth was lower than 706.7 mg · L-1, the anaerobic fermentation did not obviously inhibit the growth of the anaerobic fermentation broth.The decrease of VFA in anaerobic fermentation broth and the cumulative methane production With the increase of Cu and Zn concentration in the mixed materials, the cumulative amount of methane produced showed a downward trend (except for Zn100 treatment). When Cu <413.7 mg · kg-1 or Zn <500.6 mg · kg- 1, the effect on anaerobic fermentation was not obvious. When Cu> 513.7 mg · kg-1 and Zn> 600.6 mg · kg-1, the anaerobic fermentation was significantly inhibited and the inhibition of Cu to anaerobic fermentation (P <0.05). The activities of Cu, Zn and cellulase, invertase and urease in fermentation broth were negatively correlated (p≤0.05). The activities of cellulase, sucrase and urease And cumulative methane production were significantly and positively correlated (p≤0.05); Zn treated cellulase activity and sucrase activity and its Significant positive correlation (p≤0.05), but associated with urease activity was not significant, indicating that Cu, Zn may be generated on the amount of influence the anaerobic methane fermentation process and by affecting the enzymatic activity accumulation.