Mechanistic analysis of membrane fouling by microplastics in a gravity-driven ceramic membrane reactor for roofing rainwater reuse

• Published in: Journal of membrane science Vol. 707; p. 122995
• Main Authors: Song, Wei, Li, Jiawan, Liu, Chuanxi, Du, Xing, Wang, Zhihong, Lin, Dachao, Li, Xianhui
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2024
• Subjects: Diverse microplastics; Fouling mechanism; Gravity-driven ceramic membrane; Microplastics; Roofing rainwater; Roofing rainwater; Microplastics; Diverse microplastics; Gravity-driven ceramic membrane; Fouling mechanism
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2024.122995

The presence of microplastics (MPs) in aquatic environments is a direct consequence of human activities and social development. Consequently, the removal of MPs is essential in water treatment processes, including the membrane filtration of roofing rainwater. Additionally, MPs carried by roofing rainwater pose potential risks to both the ecosystem and human health. However, the fouling behavior of MPs and their impact on the performance of gravity-driven ceramic membranes (GDCMs) remains largely unexplored. In this study, we investigated the effects of the coexisted MPs in rainwater, specifically granulate and fiber MPs, on the formation of fouling layers. We examined their physical and biological characteristics, such as components and microbial community structure. The results demonstrated a positive correlation between the formation of the biological functional layer and the diverse morphology of MPs, which led to a significant decrease in membrane permeability and exacerbated membrane fouling, while having no remarkable influence on permeate quality. Furthermore, different shapes of MPs exhibited varying characteristics: the cake layer of the granulate-MPs group exhibited superior compressibility, while the fiber-MPs group formed and matured more rapidly. MPs not only directly combined with organic matter but also induced metabolic products of microorganisms. Therefore, understanding the primary mechanisms of membrane fouling by MPs in GDCMs for roofing rainwater reuse is of utmost importance. Our study presents novel insights into the mechanisms of membrane fouling in the presence of coexisting MPs in roofing rainwater reuse and provides guidance for improving the performance of GDCMs in the presence of MPs. [Display omitted] •The shape of MPs in rainwater exhibits significant effect on membrane fouling.•Granulate-MPs cake layer was easily compacted and fiber-MPs benefit for the cake layer growth.•The complexation of MPs and organic was confirmed as the dominant fouling mechanism.•MPs in rainwater only affect membrane fouling behavior but not permeate quality.