Hydrolysis capacity of different sized granules in a full-scale aerobic granular sludge (AGS) reactor

Ortega, S.; Berg, Lenno van den; Pronk, Mario; Kreuk, Merle de

doi:10.1016/j.wroa.2022.100151

Cited by 16 publications

(3 citation statements)

References 67 publications

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“…Then, for all conditions, preferential selection for PAOs and GAOs will result from a duly operated anaerobic selector by managing the contact time between the influent wastewater and the biomass to enable hydrolysis, fermentation, and VFA uptake by these organisms prior to switching aeration or anoxic phases on. In granular sludge systems, this can occur via well-designed bed geometries and hydraulic conditions under slow up-flow feeding conditions, and/or by the integration of a subsequent anaerobic batch phase to promote the hydrolysis, fermentation, and uptake of VFAs by PAOs or GAOs (de Kreuk and van Loosdrecht, 2004; Weissbrodt et al, 2013b; Lochmatter and Holliger, 2014; Pronk et al, 2015b; Wagner et al, 2015; Derlon et al, 2016; Weissbrodt et al, 2017; Winkler et al, 2018; Toja Ortega et al, 2022; van Dijk et al, 2022).…”

Section: Discussionmentioning

confidence: 99%

Production of extracellular polymeric substances in granular sludge under selection forAccumulibacterandCompetibacter

Guimarães

Gubser

Lin

et al. 2023

Preprint

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Granular sludge intensifies the removal of nutrients from wastewater. Granules structured by extracellular polymeric substances (EPS) can be recovered as biomaterial. Links between microbial selection and EPS formation during granulation need to get uncovered. We inoculated anaerobic-aerobic sequencing batch reactors with either flocs or granules to study the relationships between microbial selection, bioaggregation, exopolymer formation, and EPS composition. Selection for slow-growing organisms like the model polyphosphate-accumulating organism "Candidatus Accumulibacter" (max. 83% vs. amplicon sequencing read counts) and glycogen-accumulating organism "Ca. Competibacter" (max. 45%) sustained granulation. Gel-forming exopolymers were produced as high as above 40% of the volatile solids of the biomass by stepwise increase of the organic loading rate (0.3 to 2.0 g CODAc d-1 LR-1). Confocal laser scanning microscopy, FT-IR spectroscopy, and HPAE-PAD chromatography revealed the complex and dynamic chemical compositions of the structural EPS in relation to microbial population shifts along reactor regimes. The analysis of 20 representative genomes of "Ca. Accumulibacter" and "Ca. Competibacter" recovered from public databases revealed their functional potential to produce EPS among other representative wastewater microorganisms. The more than 40 functional gene categories annotated highlight the complexity of EPS metabolic networks from monomers processing to assembly, export, and epimerizations. The combination of ecological engineering principles and systems microbiology will help unravel and direct the production of EPS from wastewater, valorizing residual granular sludge into beneficial biomaterials for the circular economy.

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Section: Discussionmentioning

confidence: 99%

Production of extracellular polymeric substances in granular sludge under selection forAccumulibacterandCompetibacter

Guimarães

Gubser

Lin

et al. 2023

Preprint

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“…By comparison, smaller granules (0.5 mm) were relatively an excellent selection for minimizing N 2 O production at the appropriate DO level (e.g., 3.0 mg-O 2 /L) and lower NO 2 – contents. Generally, a range of granule diameters has been reported, varying from 0.2 to 3.0 mm. ,, Through efficient screening, smaller granules could be cultured in the full-scale AGS systems. For example, it is possible to establish a setup for periodic rapid screening in the mainstream AGS process to roughly sort out aerobic granules of various sizes.…”

Section: Discussionmentioning

confidence: 99%

“…Generally, a range of granule diameters has been reported, varying from 0.2 to 3.0 mm. 27,34,61 Through efficient screening, smaller granules could be cultured in the full-scale AGS systems. For example, it is possible to establish a setup for periodic rapid screening in the mainstream AGS process to roughly sort out aerobic granules of various sizes.…”

Section: Environmental Science and Technologymentioning

confidence: 99%

Smaller Aerobic Granules Significantly Reduce N₂O Production by Ammonia-Oxidizing Bacteria: Evidences from Biochemical and Isotopic Analyses

Liu,

Zhao

et al. 2023

Environ. Sci. Technol.

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The mitigation of nitrous oxide (N2O) is of primary significance to offset carbon footprints in aerobic granular sludge (AGS) systems. However, a significant knowledge gap still exists regarding the N2O production mechanism and its pathway contribution. To address this issue, the impact of varying granule sizes, dissolved oxygen (DO), and nitrite (NO2 –) levels on N2O production by ammonia-oxidizing bacteria (AOB) during nitrification in AGS systems was comprehensively investigated. Biochemical and isotopic experiments revealed that increasing DO or decreasing NO2 – levels reduced N2O emission factors (by 13.8 or 19.5%) and production rates (by 0.08 or 0.35 mg/g VSS/h) via weakening the role of the AOB denitrification pathway since increasing DO competed for more electrons required for AOB denitrification. Smaller granules (0.5 mm) preferred to diminish N2O production via enhancing the role of NH2OH pathway (i.e., 59.4–100% in the absence of NO2 –), while larger granules (2.0 mm) induced conspicuously higher N2O production via the AOB denitrification pathway (approximately 100% at higher NO2 – levels). Nitrifying AGS systems with a unified size of 0.5 mm achieved 42% N2O footprint reduction compared with the system with mixed sizes (0.5–2.0 mm) under optimal conditions (DO = 3.0 mg-O2/L and NO2 – = 0 mg-N/L).

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Concluding Remarks and Outlook

Weissbrodt

2024

Springer Theses

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Hydrolysis capacity of different sized granules in a full-scale aerobic granular sludge (AGS) reactor

Cited by 16 publications

References 67 publications

Production of extracellular polymeric substances in granular sludge under selection forAccumulibacterandCompetibacter

Production of extracellular polymeric substances in granular sludge under selection forAccumulibacterandCompetibacter

Smaller Aerobic Granules Significantly Reduce N₂O Production by Ammonia-Oxidizing Bacteria: Evidences from Biochemical and Isotopic Analyses

Concluding Remarks and Outlook

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Hydrolysis capacity of different sized granules in a full-scale aerobic granular sludge (AGS) reactor

Cited by 16 publications

References 67 publications

Production of extracellular polymeric substances in granular sludge under selection forAccumulibacterandCompetibacter

Production of extracellular polymeric substances in granular sludge under selection forAccumulibacterandCompetibacter

Smaller Aerobic Granules Significantly Reduce N2O Production by Ammonia-Oxidizing Bacteria: Evidences from Biochemical and Isotopic Analyses

Concluding Remarks and Outlook

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Smaller Aerobic Granules Significantly Reduce N₂O Production by Ammonia-Oxidizing Bacteria: Evidences from Biochemical and Isotopic Analyses