초록
<P><B>Abstract</B></P> <P>The comparative process performance and efficiency of reactors treating swine wastewater for biogas production at 35 °C were evaluated for three biomass-retaining reactors with different configurations and operational conditions: an anaerobic sequencing batch reactor (ASBR), an upflow anaerobic sludge bed-filter (UBF) and an upflow solid reactor (USR). The maximum volumetric methane production rates of the ASBR, UBF and USR were 1.679, 1.669 and 1.234 L L<SUP>−1</SUP> d<SUP>−1</SUP>, respectively, at the OLR of 8 g TS L<SUP>−1</SUP> d<SUP>−1</SUP>. Compared with the USR, the ASBR and UBF achieved better performance, which was attributed to more efficient biomass retention indicated by a higher solids residence time-to-hydraulic residence time ratio. The worst performance of the USR was caused by serious washout of sludge. The microorganism distribution profile along with depth showed that methanogenic genera of <I>Methanosaeta</I> and <I>Methanospirillum</I> accounted for 81.37–90.83% and 77.67–88.50% of all archaeal clones in the ASBR and UBF, respectively, and presented non-obvious spatial heterogeneity, while the abundances of methanogenic genera decreased from 93.61 to 4.64% with depth in the USR, instead of an increase in the populations of acid resistant bacteria.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Three biomass-retaining reactors of the ASBR, the UBF and the USR were compared. </LI> <LI> The SRT/HRT ratio was proposed to evaluate the performance of reactor. </LI> <LI> The ASBR and the UBF showed better performance than the USR. </LI> <LI> Microorganism distribution profile with the reactor’ depth was described. </LI> <LI> Distinct community structures were formed in the USR due to acidification. </LI> </UL> </P>