Comparison of hyper-thermophilic-mesophilic two-stage with single-stage mesophilic anaerobic digestion of waste activated sludge: Process performance and microbial community analysis

Li Jie Wu, Atsushi Higashimori, Yu Qin, Toshimasa Hojo, Kengo Kubota, Yu You Li

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)

Abstract

The conventional mesophilic digestion of waste activated sludge (WAS) is challenged by the updated wastewater treatment process. A hyper-thermophilic (70 °C)-mesophilic (35 °C) temperature-phased two-stage systems without and with recirculation were employed to upgrade the single-stage mesophilic digestion of waste activated sludge in this study. The solid reduction increased by more than 10% in the two-stage systems. Similar methane production was observed in the single-stage system and two-stage systems, with a methane yield of 0.24 L/g VS added. In the case of two-stage system without recirculation, hyper-thermophilic stage played an important role in COD solubilization, with 34.4% of the WAS solubilized in that stage, while mesophilic stage contributed more in methane production, with 36.2% of COD in the WAS produced as methane in the mesophilic stage. Firmicutes became the most dominant bacteria phylum in the mesophilic stages of two-stage systems as compared to the dominant phylum Proteobacteria in single-stage system, with the genus Methanothermobacter cardinal in the hyper-thermophilic stage. The recirculation in the two-stage system increased the microbial community diversity in the hyper-thermophilic stage, which was one factor to result in improved methane production in the hyper-thermophilic stage.

Original languageEnglish
Pages (from-to)290-301
Number of pages12
JournalChemical Engineering Journal
Volume290
DOIs
Publication statusPublished - 2016 Apr 15

Keywords

  • Hyper-thermophilic
  • Recirculation
  • Temperature-phased anaerobic digestion (TPAD)
  • Two-stage
  • Waste activated sludge (WAS)

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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