Establishment and differential performance of hyperthermophilic microbial community during anaerobic self-degradation of waste activated sludge
| Autor: | Fan Yang, Xiao-Xiao Li, Zhi-Feng Qin, Li-Jie Wu, Yong-Kang Lyu, Quan Zhou, Rui-Peng Ren |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Firmicutes
Methanogenesis Population Methanospirillum 010501 environmental sciences Methanothermobacter 01 natural sciences Biochemistry 03 medical and health sciences 0302 clinical medicine Bioreactors RNA Ribosomal 16S 030212 general & internal medicine Food science Anaerobiosis education 0105 earth and related environmental sciences General Environmental Science education.field_of_study biology Sewage Chemistry Microbiota Temperature biology.organism_classification Archaea Anaerobic digestion Activated sludge Methane Mesophile |
| Zdroj: | Environmental research. 191 |
| ISSN: | 1096-0953 |
| Popis: | Hyperthermophilic anaerobic digestion, especially at 70 °C, has drawn wide attention. In order to acquire the inoculum and digestion characteristics, batch acclimation and continuous operation experiments were conducted under hyperthermophilic (70 °C), thermophilic (55 °C) and mesophilic (35 °C) conditions, respectively. Archaea at each temperature was successfully enriched from the sole-source waste activated sludge (WAS). Hyperthermophilic digestion achieved higher archaea diversity, close to the Shannon index 2.23 for the thermophilic digestion, but the population were not improved, at a 16S rRNA genes 5.99 × 105 copies mL−1. Hydrogenotrophic methanogens, Methanospirillum and Methanothermobacter, dominated in the hyperthermophilic digester, accounting for 27.15%, while the primary phylum Firmicutes was promoted to 36.31%, with the proteolytic genus Coprothermobacter in Firmicutes at 19.50%. Refractory organic fractions were converted more with a higher digestion temperature, which was demonstrated by the fact that the COD/VS increased to 5.8, 5.2 and 4.2 at 70 °C, 55 °C and 35 °C, respectively, at the end of batch acclimation. In addition, the most solubilization for the dominant fraction protein in the WAS occurred at 70 °C as well. Similar hydrolysis ratio, over 10%, and specific hydrolysis rate, around 0.025 g COD (g VSS·d)−1, were achieved at 70 °C and 55 °C. The higher hydrolysis for hyperthermophilic digestion even resulted in a higher methane yield than that for the mesophilic digestion. Nevertheless, contrary to higher hydrolysis, methanogenesis limited hyperthermophilic digestion in WAS degradation, with an ultimate methane yield 71.2 mL g−1 VSadded, despite an almost complete VFA conversion through the continuous operation. |
| Databáze: | OpenAIRE |
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