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Exploring the mechanisms of decreased methane during pig manure and wheat straw aerobic composting covered with a semi-permeable membrane

Ma, Shuangshuang, Sun, Xiaoxi, Fang, Chen, He, Xueqin, Han, Lujia, Huang, Guangqun
Waste management 2018 v.78 pp. 393-400
aeration, carbon, composting, genes, methane, methane production, nitrogen, oxygen, pig manure, temperature, water content, wheat straw
It is very important to reduce methane production and emission during aerobic composting. In this study, the effects of covering with a semi-permeable membrane during pig manure and wheat straw composting were investigated. Two laboratory-scale composting reactors were used: the membrane covered treatment (treatment A) and the control treatment (treatment B). Composting in treatment A effectively improved the oxygen utilization rate and decreased methane emissions by 22.42% relative to the control treatment. Quantification of functional genes and Pearson rank correlations showed that the mcrA and mcrA/pmoA gene abundances were significantly positively correlated with temperature and negatively correlated with the interstitial oxygen concentration, and that the pmoA gene abundance was positively correlated with the carbon: nitrogen ratio and moisture content. Therefore, increasing the aeration rate and optimizing the carbon: nitrogen ratio and moisture content will decrease methane emissions. Together, the results demonstrate that coverage membrane could be a novel strategy for reducing methane emissions during composting.