"Enhanced Microcystis Aeruginosa removal and novel flocculation mechani" by Haiyang Zhang, Lili Li et al.
 

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

This document is currently not available here.

Share

COinS