Unraveling the mechanistic role of algogenic organic matter (AOM) in coagulation efficiency: How interspecific variations in AOM govern coagulant dosage, floc characteristics, and settling dynamics----Institute of Hydrobiology, Chinese Academy of Sciences

Publications

Title：	Unraveling the mechanistic role of algogenic organic matter (AOM) in coagulation efficiency: How interspecific variations in AOM govern coagulant dosage, floc characteristics, and settling dynamics
First author：	Hu, Yuehang; Wang, Zimin; Li, Bo; Cheng, Shaozhe; Yang, Ping; Zhang, Haiyang; Li, Shouchun; Zhang, Xuezhi
Journal：	SEPARATION AND PURIFICATION TECHNOLOGY
Years：	2025
Volume / issue：	/
DOI：	10.1016/j.seppur.2025.133625
Abstract：	Algogenic organic matter (AOM) critically impacts the efficiency of drinking water treatment, but the mechanistic differences in the coagulation performance of AOM from different algal species remain unclear. This study systematically compared AOM from Microcystis aeruginosa (cyanobacteria), Scenedesmus acuminatus (green algae), Pseudanabaena cinerea (cyanobacteria), and Cyclotella meneghiniana (diatom) in terms of coagulant dosage, floc characteristic (size, fractal dimension), and settling dynamics. Results revealed that M. aeruginosa AOM, rich in carboxyl groups (139.97 mmol/gC) and macromolecular proteins (>4000 Da), increased polyaluminum chloride (PACl) dosage by 7-fold versus cell-only systems, forming loose flocs (fractal dimension D-f = 1.13) with sluggish settling (1.26 m/h). In contrast, AOM from S. acuminatus and C. meneghiniana enhanced sweep-flocculation via intermediate peptides (1000-4000 Da), yielding compact flocs (D-f > 1.37) with at least 2.7 times faster settling. Ozonation experiments demonstrated that oxidizing M. aeruginosa AOM reduced functional groups by 25.9 % and PACl dosage by 24 %, while improving D-f to 1.29. These findings revealed that AOM characteristics determined coagulation performance, providing actionable strategies for algae-laden water treatment optimization.