earticle

영어

In a two-stage anaerobic digestion process treating swine wastewater, the population dynamics of methanogens in the methanogenic stage were monitored at order level using real-time PCR at hydraulic retention times (HRTs) ranging from 25 to 5 d. Decreasing HRTs increased the loading rates of acetic, propionic, and butyric acids and ammonia. The relationship between the loading rate variation and methanogen community dynamics, and the relationship of these dynamics on daily methane production (DMP) and methane yield was statistically investigated using redundancy analysis. Methanomicrobiales (MMB) began to be dominant at longer than 12.5 d HRT, Methanosarcinales (MSL) was dominant at 8, 10, and 12.5 d HRT, and Methanobacteriales (MBT) was dominant at shorter than 6 d HRT. Increased loading rates of volatile fatty acids (VFAs) and ammonia increased MBT, decreased MMB, and had no significant effect on MSL. DMP was positively correlated with populations of aceticlastic MSL. Methane yield increased slightly as MMB and MSL became predominant but decreased as MBT became predominant. The loading rates investigated seemed to be a selective pressure on the composition of methanogens; the methane production, in turn, was correlated with the methanogen community structure.