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Updated: Oct 22, 2025
Sampling, Sorting, and Characterizing Microplastics in Aquatic Environments with High Suspended Sediment Loads and Large Floating Debris
Published on: July 28, 2018
Effects of microplastics accumulation on performance of membrane bioreactor for wastewater treatment
QiaoYing Wang1, YanLi Li2, YingYing Liu3
1State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
Abstract:
The effective interception of membrane leads to the accumulation of microplastics (MPs) in membrane bioreactor (MBR) process for long-term operation. However, the influence of MPs accumulation on the performance of MBR hasn't been well understood. In this study, the accumulation of polypropylene microplastics (PP-MPs) in two MBRs run for 3 yr with or without discharging sludge was simulated by operating the lab-scale MBRs for 84 days. The variations of pollutant removal, membrane fouling, composition of soluble microbial product (SMP) and extracellular polymeric substance (EPS), and microbial community of MBRs were systematically investigated. The results show that the removal efficiency of COD and NH4+-N was not depressed by PP-MPs accumulation. However, the presence of PP-MPs in the range of 0.14-0.30 g/L could inhibit the growth of microorganisms, enhance the secretion of SMP and EPS, and reduce the microbial richness and diversity. In the contrary, the high concentration of PP-MPs (2.34-5.00 g/L) exhibited the opposite effects and mitigated membrane fouling, suggesting the important role of MPs concentration. It was also found that the exposure to high concentration of PP-MPs enhanced relative abundance of Clostridia, and inhibited the growth of Proteobacteria. The findings of this study provide a foresight to understand the effects of MPs accumulation on the performance of MBRs.
Insights
Microplastic accumulation in membrane bioreactors (MBRs) impacts microbial communities and membrane fouling. Low microplastic concentrations inhibit microbes, while high concentrations mitigate fouling, highlighting the importance of concentration in MBR performance.
Area of Science:
- Environmental Science
- Environmental Engineering
- Microbiology
Background:
- Microplastics (MPs) accumulate in membrane bioreactors (MBRs) during long-term operation.
- The impact of accumulated MPs on MBR performance remains poorly understood.
- Polypropylene microplastics (PP-MPs) are a common pollutant in aquatic environments.
Purpose of the Study:
- To investigate the effects of PP-MPs accumulation on MBR performance.
- To analyze variations in pollutant removal, membrane fouling, and microbial community.
- To determine the influence of different PP-MPs concentrations on MBR processes.
Main Methods:
- Simulated PP-MPs accumulation in lab-scale MBRs over 84 days.
- Systematic investigation of pollutant removal (COD, NH4+-N).
- Analysis of membrane fouling, soluble microbial products (SMP), extracellular polymeric substances (EPS), and microbial community composition.
Main Results:
- PP-MPs accumulation did not significantly reduce COD and NH4+-N removal efficiency.
- Low PP-MPs concentrations (0.14-0.30 g/L) inhibited microbial growth, increased SMP/EPS, and reduced microbial diversity.
- High PP-MPs concentrations (2.34-5.00 g/L) mitigated membrane fouling and showed opposite effects on microbial communities, enhancing Clostridia and inhibiting Proteobacteria.
Conclusions:
- MP concentration is a critical factor influencing MBR performance and microbial community structure.
- Understanding MP accumulation effects is crucial for optimizing MBR operation and mitigating environmental impacts.
- High concentrations of PP-MPs may offer a potential strategy for fouling mitigation in MBRs.
