Simultaneous removal of Microcystis aeruginosa and microplastics by oxidation enhanced coagulation

Wenjun Du; Xin Xu; Lili An; Feng Yan; J Paul Chen; Ruihua Dai

doi:10.1016/j.envpol.2024.125555

Simultaneous removal of Microcystis aeruginosa and microplastics by oxidation enhanced coagulation

Environ Pollut. 2024 Dec 17:366:125555. doi: 10.1016/j.envpol.2024.125555. Online ahead of print.

Authors

Wenjun Du¹, Xin Xu¹, Lili An¹, Feng Yan¹, J Paul Chen², Ruihua Dai³

Affiliations

¹ Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China.
² Department of Civil and Environmental Engineering, National University of Singapore, 10 Kent Ridge, 119260, Singapore; College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China.
³ Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China; Department of Civil and Environmental Engineering, National University of Singapore, 10 Kent Ridge, 119260, Singapore. Electronic address: rhdai@fudan.edu.cn.

PMID: 39701368
DOI: 10.1016/j.envpol.2024.125555

Abstract

The composite pollution is an increasingly severe challenge in the field of water treatment. Especially, microplastics (MPs) contamination and Microcystis aeruginosa (M. aeruginosa) were verified that they could synergistically pose a serious threat to safety of drinking water. Therefore, developing effective removal technology is an urgent task. In this study, the simultaneous removal of M. aeruginosa and polystyrene (PS, a typical plastic matter) was investigated by H₂O₂ enhanced Fe(II) coagulation. The results demonstrated that the removal rate of both algae and PS can reach over 90%. It was also demonstrated that the PS removal efficiency increased from 23.3% to 97.3% with the increase of M. aeruginosa biomass from 0 cells/mL to 0.5 × 10⁶ cells/mL. The possible reason might be that the addition of algal cells raises the number of contaminant particles, which greatly increases the floc size during the coagulation process. It makes MPs easier to be trapped by sweep flocculation in this process. Additionally, naturally weathered polystyrene (NWPS) exhibited higher removal rate than virgin PS, due to more original functional groups, larger particle size (d₅₀ 9.75 μm-11.25 μm), and a lower absolute zeta potential (-34.15 mV to -30.1 mV). Furthermore, low Fe residue level and AOM (algal organic matter) control was simultaneously achieved in this process (TOC <1 mg/L, MCs <1 μg/L). Therefore, this study suggests that the H₂O₂-Fe(II) process is an efficient and green technology for the removal of M. aeruginosa and PS composite pollutants without secondary pollution, which is promising technology in drinking water treatment plant.

Keywords: Composite pollutants; Microcystis aeruginosa; Natural weathering; Oxidation enhanced coagulation; Polystyrene.