Revealing the influencing mechanisms of polystyrene microplastics (MPs) on the performance and stability of the algal-bacterial granular sludge

• Published in: Bioresource technology 2022-06, Vol.354, p.127202-127202, Article 127202
• Main Authors: Huang, Shuchang, Zhang, Bing, Liu, Yi, Feng, Xueli, Shi, Wenxin
• Format: Article
• Language: English
• Subjects: Algal-bacterial granular sludge; Microbial community structure; Microplastics; Nutrient removal; Polystyrene
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2022.127202

[Display omitted] •ABGS exhibited a high removal efficiency of polystyrene MPs (over 96%).•The characteristics of ABGS were not significantly affected by MPs.•COD and TP removal efficiencies were inhibited by the MPs in the ABGS system.•The stability of ABGS was damaged due to the generation of ROS induced by MPs.•The influencing mechanisms of MPs on the ABGS system were carefully revealed. Algal-bacterial granular sludge (ABGS) is an energy-saving and environment-friendly wastewater treatment technology; however, the effects of microplastics (MPs) on the performance and stability of the ABGS system remain unknown. Herein, the influencing mechanisms of polystyrene MPs (50 μm) on the ABGS were systematically investigated. The ABGS exhibited a high removal efficiency of MPs (over 96%) at 1 mg/L and 20 mg/L. Although the biomass content, sludge settling and particle size were not obviously affected by MPs, the COD and total phosphorus (TP) removal efficiencies were inhibited by 2.6%-4.1% and 2.9%-5.8%, respectively. Meanwhile, the structural stability of ABGS was damaged by MPs, owing to the excessive oxidative stress, low content of protein-like substance (especially tryptophan and tyrosine), and the large portion of loose protein secondary structure. Microbial community analysis revealed that the relative abundance of some functional bacteria (Candidatus_Competibacter and Rhodobacter) and algal species (Tetradesmus) were decreased under the MPs stress.