Shandong Science ›› 2025, Vol. 38 ›› Issue (5): 123-130.doi: 10.3976/j.issn.1002-4026.20240126

• Environment and Ecology • Previous Articles     Next Articles

Effects of different coagulants on the anaerobic biodegradation of microcystin-LR in water treatment

MA Guangxiang1,2,3(), JU Tiantian4,*(), XIA Yanzhao1, CHEN Linlin1, SONG Wenyang1, LIU Yue1   

  1. 1. Shandong Wolan Environmental Technology Co.,Ltd,Jinan 250014,China
    2. Shandong University,Jinan 250100,China
    3. Shandong Society of Environmental Sciences,Jinan 250014,China
    4. Shandong Provincial Construction Project Environmental Review Service Center,Jinan 250011,China
  • Received:2024-11-04 Revised:2025-01-10 Published:2025-10-20 Online:2025-10-11

Abstract:

This study investigated the effects of different coagulants—namely chitosan,polyaluminum chloride (PAC),and ferric chloride (FeCl3)—on cyanobacterial cell breakage and microcystin-LR (MC-LR) anaerobic biodegradation in raw water containing algae during conventional drinking-water treatment. Analyses were conducted using three-dimensional excitation emission matrix (3D-EEM) fluorescence spectroscopy,scanning electron microscopy,and enzyme-linked immunosorbent assays. Results showed that coagulated flocs generated by the action of FeCl3 had no significant effect on cyanobacterial cell breakage or total MC-LR degradation. Chitosan initially protected cyanobacterial cells and adsorbed extracellular MC-LR; however,its effectiveness declined over time. Meanwhile,PAC significantly exacerbated cyanobacterial cell breakage,leading to the massive release of intracellular toxins,which ultimately accelerated the degradation rate of total MC-LR. In addition,3D-EEM fluorescence spectroscopy revealed increasing concentrations of five substance types,such as the ammoniacal/tryptophan protein zone and tyrosine/tryptophan zone,indicating that the different coagulants had a significant effect on the production of extracellular polymers in the sludge. Further,the related substances increased in amount the fastest when PAC was used. This study is the first to systematically investigate the mechanisms by which coagulants affect cyanobacterial cells and MC-LR anaerobic degradation,providing an important reference for the efficient removal of cyanobacteria and their toxins from waterworks sludge.

Key words: waterworks sludge, microcystin-LR, coagulant flocs, alga-containing sludge, anaerobic biodegradation

CLC Number: 

  • X703