Exploring the microbial mechanism of reducing methanogenesis during dairy manure membrane-covered aerobic composting at industrial scale

In this study, the microbial mechanism of reducing methanogenesis during membrane-covered aerobic com-posting from solid dairy manure was investigated. An industrial-scale experiment was carried out to compare a static composting group (SC) and a forced aeration composting group (AC) with a semipermeable membrane-covered composting group (MC + AC). The results showed that the semipermeable membrane-covered could improve the oxygen utilization rate and inhibit the anaerobic bacterial genus Hydrogenispora and archaea order Methanobacteriales. During the membrane-covered period, the acetoclastic methanogenesis module in MC + AC, AC and SC decreased by 0.58%, 0.05% and 0.04%, respectively, and the cdhC gene in the acetoclastic pathway was found to be decreased by 65.51% only in MC + AC. Changes in methane metabolism pathways resulted in a 27.48% lower average methane concentration in MC + AC than in SC. Therefore, the semipermeable membrane-covered strategy can effectively reduce methane production during dairy manure aerobic composting by restricting the methanogenesis of the acetoclastic pathway.

Automated summary

This study investigated the microbial mechanism of reducing methane production during aerobic composting of solid dairy manure with a membrane cover. The results showed that the semipermeable membrane cover improved oxygen utilization rate and inhibited the growth of anaerobic bacteria and archaea. The acetoclastic methanogenesis module decreased by 0.58%, 0.05%, and 0.04% in the MC + AC, AC, and SC groups, respectively. The cdhC gene in the acetoclastic pathway was decreased by 65.51% only in the MC + AC group. The changes in methane metabolism pathways resulted in a 27.48% lower average methane concentration in the MC + AC group compared to the SC group. Therefore, the semipermeable membrane cover strategy effectively reduces methane production during dairy manure aerobic composting by restricting methane generation through the acetoclastic pathway.