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Zhang H, Li L, Cheng S, Li C, Liu F, Wang P, Sun L, Huang J, Zhang W, Zhang X. Enhanced Microcystis Aeruginosa removal and novel flocculation mechanisms using a novel continuous co-coagulation flotation (CCF). THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159532. [PMID: 36257435 DOI: 10.1016/j.scitotenv.2022.159532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 10/13/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
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.
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Affiliation(s)
- Haiyang Zhang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Lili Li
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shaozhe Cheng
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Cheng Li
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Fangzhou Liu
- Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, NJ 07102, United States
| | - Peizhong Wang
- Wuxi Gongyuan Environmental Technology Stock CO., Ltd, Wuxi, Jiangsu 214194, China
| | - Lianjun Sun
- Wuxi Gongyuan Environmental Technology Stock CO., Ltd, Wuxi, Jiangsu 214194, China
| | - Junbo Huang
- Wuxi Gongyuan Environmental Technology Stock CO., Ltd, Wuxi, Jiangsu 214194, China
| | - Wen Zhang
- Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, NJ 07102, United States.
| | - Xuezhi Zhang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China.
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Li L, Zhang H, Mubashar M, Chen L, Cheng S, Zhang X. Parallel filtration for solid-liquid separation: A case study of highly-efficient algal removal under parallel configuration driven by magnetic force. Sep Purif Technol 2023. [DOI: 10.1016/j.seppur.2023.123098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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New Insights into Microbial Degradation of Cyanobacterial Organic Matter Using a Fractionation Procedure. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19126981. [PMID: 35742228 PMCID: PMC9222324 DOI: 10.3390/ijerph19126981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 05/31/2022] [Accepted: 06/01/2022] [Indexed: 02/06/2023]
Abstract
Cyanobacterial blooms caused by phytoplankton Microcystis have occurred successively since 1980 in Lake Taihu, China, which has led to difficulty collecting clean drinking water. The effects of cyanobacterial scum-derived dissolved organic matter (DOM) on microbial population variations and of algal-derived filtrate and algal residual exudative organic matter caused by the fraction procedure on nutrient mineralization are unclear. This study revealed the microbial-regulated transformation of DOM from a high-molecular-weight labile to a low-molecular-weight recalcitrant, which was characterized by three obvious stages. The bioavailability of DOM derived from cyanobacterial scum by lake microbes was investigated during 80-d dark degradation. Carbon substrates provided distinct growth strategy links to the free-living bacteria abundance variation, and this process was coupled with the regeneration of different forms of inorganic nutrients. The carryover effects of Microcystis cyanobacteria blooms can exist for a long time. We also found the transformation of different biological availability of DOM derived from two different cyanobacterial DOM fractions, which all coupled with the regeneration of different forms of inorganic nutrients. Our study provides new insights into the microbial degradation of cyanobacterial organic matter using a fractionation procedure, which suggests that the exudate and lysate from degradation products of cyanobacteria biomass have heterogeneous impacts on DOM cycling in aquatic environments.
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