Microbial population dynamics in temperature‐phased anaerobic digestion of municipal wastewater sludge. Issue 6 (23rd April 2019)

• Record Type: Journal Article
• Authors: Hameed, Syeda A; Riffat, Rumana; Li, Baoqiang; Naz, Iffat; Badshah, Malik; Ahmed, Safia; Ali, Naeem
• Is Part Of: Journal of chemical technology & biotechnology. Volume 94:Issue 6(2019)
• Page Start: 1816
• Page End: 1831
• Publication Date: 2019-04-23
• Subjects: anaerobic digestion -- 454 pyrosequencing -- Illumina sequencing -- temperature‐phased anaerobic digestion -- wastewater sludge; Biotechnology -- Periodicals; Chemistry, Technical -- Periodicals; Chemical engineering -- Periodicals; Industries -- Environmental aspects -- Periodicals; 660
• DOI: 10.1002/jctb.5955
• Languages: English
• ISSNs: 0268-2575

Abstract

Abstract: BACKGROUND: The present study compared the performance and capability of thermophilic–mesophilic, temperature‐phased anaerobic digestion (TPAD) of wastewater sludge at 45 and 55 °C in terms of rate of hydrolysis and methanogenesis at two point interval times – December and January – with operational conditions kept constant (total solid content 6.5%, solids retention time 12.5 days). RESULTS: The reduction of volatile solids (VS) was 77% at 45 °C TPAD‐1 and 72% at 55 °C TPAD‐II. The accumulation of ammonia and volatile fatty acids (VFAs; propionic acid) were observed to be below the inhibitory range (>3000 mg L −1 ), whereas the methane (CH4 ) production (45 °C, 3.55 ± 0.47 L CH4 L −1 day −1 ; 35 °C, 1.44 ± 0.12 L CH4 L −1 day −1 ) remained considerably higher in TPAD‐I than TPAD‐II. Furthermore, the TPAD‐II system suffered from certain degree of instability due to high level of total VFAs (6087 ± 1578 mg L −1 ), low buffering capacity, increased level of total NH3 (2982 ± 219 mg L −1 ) and free NH3 (246 ± 25 mg L −1 ), and relatively reduced CH4 production (1.69 ± 0.1 L L −1 day). The bacterial and archaeal population of the TPADs investigated by 454 pyrosequencing and Illumina sequencing showed, in both TPAD systems, a bacterial community dominated by Firmicutes, followed by Bacteriodetes, Proteobacteria, Synergistetes and Actiniobacteria. The archaeal community was dominated by Methanimicrobia (74–84% Methanosarcina ) and Methanobacteria (15–27% Methanobacterium ). A progression from genus Clostridium to Coprothermobacter and Tepidanaerobacter, and Methanocarcina to Methanothermobacter and Methanobacterium was observed in TPAD‐II. CONCLUSIONS: This study proved the processes driving the dynamics of key microbial population and its correlation with hydrolytic functionality of TPAD systems. © 2019 Society of Chemical Industry