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Updated: Sep 26, 2025
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Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge
Published on: September 26, 2016
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Laboratory-scale study of a biodegradable microplastic polylactic acid stabilizing aerobic granular sludge system
Xin Song1, Shiquan Sun1, Yang Gao1
1School of Hydraulic Engineering, Changsha University of Science and Technology, Changsha, 410114, China; Engineering and Technical Center of Hunan Provincial Environmental Protection for River Lake Dredging Pollution Control, Changsha, 410114, China.
Environmental Pollution (Barking, Essex : 1987)
|April 23, 2022
Summary
Degradable microplastics (DMPs) like polylactic acid enhance aerobic granular sludge stability and pollutant removal. This microbial community optimization improves wastewater treatment performance.
Area of Science:
- Environmental Science
- Microbiology
- Wastewater Treatment
Background:
- Microplastics impact on aerobic granular sludge (AGS) is an emerging concern.
- The role of degradable microplastics (DMPs) in AGS systems remains largely unexplored.
- Polylactic acid (PLA) is a common DMP with potential applications in wastewater treatment.
Purpose of the Study:
- To investigate the effects of DMP-PLA on AGS stability and pollutant removal.
- To analyze the impact of DMP-PLA on microbial community structure and extracellular polymeric substances (EPS) production.
- To evaluate DMP-PLA as a method for optimizing AGS performance.
Main Methods:
- Aerobic granular sludge reactors were operated with varying concentrations of DMP-PLA (5, 15, 40 mg/L).
- Granular stability, pollutant removal efficiency (COD, TP, TIN), and EPS composition were analyzed.
- Microbial community structure was assessed using 16S rRNA gene sequencing.
- Redundancy analysis (RDA) was employed to correlate microbial abundance with DMP-PLA addition.
Main Results:
- DMP-PLA addition significantly strengthened granular stability and pollutant removal efficiency (COD >88%, TP >91%, TIN >86%).
- DMP-PLA stimulated EPS secretion, particularly retaining β-D-glucopyranose polysaccharides and maintaining hydrogen bonds.
- Microbial analysis revealed Defuviicoccus and Candidatus_Competibacter as dominant genera, associated with enhanced nitrogen removal.
- The abundance of Candidatus_Competibacter showed a positive correlation with DMP-PLA concentration.
Conclusions:
- DMP-PLA can be feasibly used to enhance the stability and performance of AGS systems.
- DMP-PLA promotes beneficial microbial communities and EPS production for improved wastewater treatment.
- This study presents a novel approach for optimizing AGS microbial communities and extracellular secretion.
