New insights on ecological roles of waste activated sludge in nutrient-stressed co-digestion

[Display omitted] •The role of waste activated sludge (WAS) in anaerobic digestion was re-evaluated.•WAS provided extra microbes, creating a chance to reach microbial niche balance.•System resiliency developed when acidogenesis and acetogenesis over hydrolysis > 0.5.•Core species’ acidogenesis an...

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Bibliographic Details
Published in:Bioresource technology 2024-06, Vol.402, p.130836-130836, Article 130836
Main Authors: Xiao, Yihang, Hao, Tianwei
Format: Article
Language:English
Subjects:
Anaerobic digestion
Anaerobiosis
Bioreactors
Carbon - metabolism
Co-digestion
Hydrolysis
Methane - metabolism
Nutrient imbalance
Nutrients - metabolism
Sewage - microbiology
Steady state
Waste sludge
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Summary:[Display omitted] •The role of waste activated sludge (WAS) in anaerobic digestion was re-evaluated.•WAS provided extra microbes, creating a chance to reach microbial niche balance.•System resiliency developed when acidogenesis and acetogenesis over hydrolysis > 0.5.•Core species’ acidogenesis and acetogenesis versatility assisted system resilience. There have been extensive applications of waste activated sludge (WAS) in anaerobic co-digestion (AcoD). Nonetheless, mechanisms through which AcoD systems maintain stability, particularly under nutrient-stressed conditions, are under-appreciated. In this study, the role of WAS in a nutrient-stressed WAS-food waste AcoD system was re-evaluated. Our findings demonstrated that WAS-based co-digestion increased methane production (by 20–60%) as WAS bolsters such systems’ resilience via establishing a core niche-based microbial balance. The carbon utilization investigation suggested a microbial niche balance is attainable if two conditions are satisfied: 1) hydrolysis efficiency is greater than 50%; and 2) both the acidogenesis-to-hydrolysis and acetogenesis-to-hydrolysis efficiencies surpass 0.5. Metagenomic assembly genome (MAG) analysis indicated that the versatile metabolic characteristics strengthened the microbial niche balance, rendering the system resilient and efficient through a syntrophic mode, contributing to both acidogenesis and acetogenesis. The findings of this study provide new insights into the ecological effects of WAS on AcoD.
ISSN:0960-8524
1873-2976
DOI:10.1016/j.biortech.2024.130836