Response of the microbial community to the methanogenic performance of biologically hydrolyzed sewage sludge with variable hydraulic retention times

• Published in: Bioresource technology 2019-09, Vol.288, p.121581-121581, Article 121581
• Main Authors: Mahdy, Ahmed, Wandera, Simon M., Bi, Shaojie, Song, Yunlong, Qiao, Wei, Dong, Renjie
• Format: Article
• Language: English
• Subjects: Anaerobic digestion; Hydraulic retention time; Hyperthermophilic biological hydrolysis; Methanogenic performance; Microbial dynamic
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2019.121581

•Effects of HRT (20-5d) on AD of biological hydrolyzed sludge was investigated.•An ‘inhibited steady state’ of methane production was observed at shorter HRT.•HRTs mediated a remarkable variation in microbial community profiles.•Sporosarcina and Methnosarcina correlated to VS removal and methane yield. Hyperthermophilic biological hydrolysis of sewage sludge was applied before long-term anaerobic digestion to investigate how shortening hydraulic retention times (HRT, 20-5d) affected methanogenic performances and microbial dynamics. Results indicated that although the three different HRTs provided a stable process with a steady-state of methane production, both methane yield (161 L kg-VSin−1, 25% higher) and volatile solids removal (VS, 50%, 2-fold higher) increased during longer HRTs. Redundancy analysis results indicated that Sporosarcina and Methnosarcina positively correlated to VS removal and methane yield, and negatively correlated to volatile fatty acids (VFAs) accumulation. The relative abundance of Coprothermobacter (>60%), syntrophic acetate oxidation bacteria (SAOB), and Methanospirillum (8–15%), increased during shorter HRTs. A slight shift to two-stage acetate conversion was observed during shorter HRTs. The results demonstrated that HRTs played a key role in shaping microbial structure, leading to a new steady-state of microbial community profiles and process performances at variable HRTs.