Enhanced Microcystis Aeruginosa removal and novel flocculation mechanisms using a novel continuous co-coagulation flotation (CCF)
Document Type
Article
Publication Date
1-20-2023
Abstract
Co-coagulation flotation (CCF) is a novel flotation technology that renders more efficient algal removal compared to traditional mechanical coagulation flotation (MCF) due to a short residence time (< 30 s) and fast rising behavior of algal flocs (> 250 m·h−1). This study compared the algal removal performance using continuous CCF and MCF using water samples taken from Lake Dianchi with severe Microcystis aeruginosa blooms. Removal efficiency, dosage of coagulant/flocculant, rising velocity and structural characteristics of the resulting flocs in the two processes were systematically compared. The results show that CCF could save >50 % polyaluminum chloride (PAC) and polyacrylamide (PAM) compared with MCF when the removal efficiency was both over 95 %. The average rising velocity of flocs in CCF could reach 254.3 m·h−1, much higher than that in MCF (154.5 m·h−1). In the respective optimal coagulation conditions, the flocs formed in CCF (G = 164.8 s−1) were larger (1843 ± 128 μm) and more spherical with a higher fractal dimension (Df = 1.85 ± 0.01) than those generated in MCF (G = 34.1 s−1). The Stokes's Law was found to correctly predict the rising velocity of spherical flocs with large fractal dimensions (Df > 1.7). In contrast, the Haarhoff and Edzwald's extended equation was more suitable for calculating the rising velocity of irregular flocs with small fractal dimension. This study provides new insights into the mechanisms of the enhanced algal removal by CCF and lays foundation for developing cost-efficient algal mitigation processes.
Identifier
85140052684 (Scopus)
Publication Title
Science of the Total Environment
External Full Text Location
https://doi.org/10.1016/j.scitotenv.2022.159532
e-ISSN
18791026
ISSN
00489697
PubMed ID
36257435
Volume
857
Grant
2018YFE0110600
Fund Ref
National Natural Science Foundation of China
Recommended Citation
Zhang, Haiyang; Li, Lili; Cheng, Shaozhe; Li, Cheng; Liu, Fangzhou; Wang, Peizhong; Sun, Lianjun; Huang, Junbo; Zhang, Wen; and Zhang, Xuezhi, "Enhanced Microcystis Aeruginosa removal and novel flocculation mechanisms using a novel continuous co-coagulation flotation (CCF)" (2023). Faculty Publications. 1986.
https://digitalcommons.njit.edu/fac_pubs/1986