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Zhang S, Cao J, Zheng Y, Hou M, Song L, Na J, Jiang Y, Huang Y, Liu T, Wei H. Insight into coagulation/flocculation mechanisms on microalgae harvesting by ferric chloride and polyacrylamide in different growth phases. BIORESOURCE TECHNOLOGY 2024; 393:130082. [PMID: 38006984 DOI: 10.1016/j.biortech.2023.130082] [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: 10/18/2023] [Revised: 11/18/2023] [Accepted: 11/19/2023] [Indexed: 11/27/2023]
Abstract
FeCl3 and polyacrylamide (PAM) had been used to investigate the effect of coagulation, flocculation, and their combination on algae cells and extracellular organic matter (EOM) at different phases. PAM tended to aggregate particle-like substances, while FeCl3 could interact with EOM. The content of EOM kept rising during the algae growth cycle, while OD680 peaked at about 3.0. At stationary phase Ⅰ, the removal efficiencies of UV254, turbidity and OD680 of the suspension conditioned with FeCl3 + PAM reached (88.08 ± 0.89)%, (89.72 ± 0.36)% and (93.99 ± 0.05)%, respectively. Nevertheless, PAM + FeCl3 exhibited the worst efficiency because of the release of EOM caused by the turbulence. The results suggested that algal cells served as a coagulation aid to facilitate floc formation, while excessive EOM deteriorated harvesting performance. The process of FeCl3 + PAM at stationary phase Ⅰ appears to be a promising technology for microalgae harvesting.
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Affiliation(s)
- Siqi Zhang
- School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, PR China
| | - Jingyi Cao
- School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, PR China
| | - Yajiao Zheng
- School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, PR China
| | - Meifang Hou
- School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, PR China
| | - Lili Song
- School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, PR China
| | - Jiandie Na
- School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, PR China
| | - Yiqiang Jiang
- School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, PR China
| | - Yichen Huang
- School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, PR China
| | - Tianyi Liu
- School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, PR China
| | - Hua Wei
- School of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai 201418, PR China.
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2
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Lv L, Yang M, Liu W. Effects of organic matter and dewaterability changes on sludge calorific value during acid treatment. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:2104-2116. [PMID: 38051485 DOI: 10.1007/s11356-023-30957-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/04/2023] [Indexed: 12/07/2023]
Abstract
Acid treatment can increase the sludge calorific value to some extent by separating inorganic elements. In order to determine the mechanism by which acidification affects the sludge calorific value from an organic perspective, we investigated the changes in organic matter and dewaterability under different pH conditions. The results of this study showed that acidification conditioning retained organic matter while removing a greater amount of inorganic elements. Furthermore, acid treatment significantly increased the zeta potential and particle size of sludge particles and facilitated the precipitation of biological organic components from the supernatant to the surface of sludge particles. Acid-treated sludge exhibited a lower moisture content and a higher proportion of organic matter, and sludge treated with H2SO4, HCl, and HNO3 exhibited respective increases in calorific values of 12.14%, 7.92%, and 8.01% under pH 2. The calorific value of the acid-treated sludge was higher, making it more suitable for subsequent incineration. The findings of this study serve as a reference and foundation for efficient sludge incineration.
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Affiliation(s)
- Lieyang Lv
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510006, People's Republic of China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, 510006, People's Republic of China
| | - Meiqi Yang
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510006, People's Republic of China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, 510006, People's Republic of China
| | - Wei Liu
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510006, People's Republic of China.
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, 510006, People's Republic of China.
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3
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Wang S, Chen H. Enhanced dewaterability of sewage sludge by grafted cationic lignin-based flocculants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166958. [PMID: 37696410 DOI: 10.1016/j.scitotenv.2023.166958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 09/13/2023]
Abstract
Lignin-based flocculants are widely used for wastewater purification, but their application in sludge dewatering has not yet been documented. In this study, a novel cationic lignin-based flocculant named LS-g-CPA was prepared by grafting cationic polyacrylamide (CPA) synthesized from methacryloyloxy ethyltrimethyl ammonium chloride (DMC) and acrylamide (AM) onto sodium lignosulfonate (LS), and its roles and underlying mechanisms in sludge conditioning were investigated. The results showed that LS-g-CPA effectively improved the dewaterability of sludge, reducing the filtration resistance and filter cake moisture content of sludge from 0.61 ± 0.05 × 1012 m/kg to 0.14 ± 0.02 × 1012 m/kg and 85.64 ± 0.25 % to 76.84 ± 0.41 %, respectively. The dewatering performance of LS-g-CPA was positively correlated with the DMC/AM ratio. The quaternary ammonium groups brought by DMC disrupted the reticular structure of extracellular polymeric substances, exposing hydrophobic residues and releasing bound water. Nevertheless, the key to LS-g-CPA for improving sludge dewatering lies more in the amphoteric flocculant properties that enhance sludge flocculation and the octopus-type structure that provides good drainage channels. This study reveals that lignin-based flocculants are effective in improving the dewaterability of sludge, which provides direct evidence for their application in sludge dewatering.
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Affiliation(s)
- Shiqin Wang
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Hongbo Chen
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China.
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4
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Shen S, Xia W, Luo Z, Pan Y, Hu P, Zhang L, Shi H, Yang H. Enhanced sludge dewaterability using a bifunctional hybrid coagulant. CHEMOSPHERE 2023; 344:140323. [PMID: 37777090 DOI: 10.1016/j.chemosphere.2023.140323] [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: 05/30/2023] [Revised: 08/16/2023] [Accepted: 09/27/2023] [Indexed: 10/02/2023]
Abstract
The combination of coagulation and addition of skeleton builder is a popular pretreatment method to improve the dewaterability of sludge. In this study, a novel bifunctional inorganic/organic hybrid coagulant (CS-Si@ATP) was designed and obtained by chemically coupling a cationic starch (CS) with a popular clay, that is, attapulgite (ATP), via a silane coupling agent (APTES) for one-step conditioning of sludge. CS-Si@ATP can evidently enhance the sludge dewatering performance compared with CS, ATP, and their simple combination due to the distinct dual functions of this hybrid coagulant. The tentacle-like cationic CS in CS-Si@ATP shows efficient charge neutralization effect to aggregate and precipitate the suspended solids for further formation of compact sludge cakes. Meanwhile, the internal ATP with a stable and rigid structure acts as the skeleton builder to notably improve the filterability and permeability of the sludge cakes. The synergistic effects of CS and ATP in CS-Si@ATP, i.e., the charge neutralization of CS and the skeleton construction of ATP, cause the evidently enhanced sludge dewaterability, with a filter cake moisture content approximately 78.30% after the mechanical dewatering at 0.05 MPa. In comparison with the traditional two-step combination process by separated addition of CS and ATP, the one-step addition of CS-Si@ATP can reduce the required ATP dose nearly an order of magnitude. Thus, CS-Si@ATP has the notable advantages of simple operation, efficient utilization of ATP and evident reduction of disposal cost. This study provides an environmentally friendly and cost-effective coagulant to further improve the dewaterability of sludge.
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Affiliation(s)
- Shaohang Shen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing. 210023, PR China
| | - Wei Xia
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing. 210023, PR China
| | - Zhang Luo
- China Railway Engineering Services Co., Ltd., Chengdu, 610083, PR China
| | - Yu Pan
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing. 210023, PR China
| | - Pan Hu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing. 210023, PR China
| | - Longguan Zhang
- China Railway Engineering Services Co., Ltd., Chengdu, 610083, PR China
| | - Hongtao Shi
- China Railway Engineering Services Co., Ltd., Chengdu, 610083, PR China
| | - Hu Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing. 210023, PR China.
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Song J, Fang W, Lai J, Cao B, Zhang T, Xu Z. Conditioning fecal sludge of public toilets with coupled zero-valent iron and persulfate: Efficiency and mechanism. JOURNAL OF HAZARDOUS MATERIALS 2023; 455:131615. [PMID: 37201282 DOI: 10.1016/j.jhazmat.2023.131615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/26/2023] [Accepted: 05/10/2023] [Indexed: 05/20/2023]
Abstract
This study investigated the efficiency of fecal sludge conditioning using peroxydisulfate (PDS) activated by zero-valent iron (ZVI). For fecal sludge obtained from public toilets in a densely-populated rural area in China, the ZVI/PDS coupling greatly improved its dewaterability as well as the supernatant quality in terms of organic matter and nutrient contents. The capillary suction time (CST) and supernatant turbidity of fecal sludge can be reduced up to 97% and 73% respectively in 10 min by the combination of 0.15 g/g TS ZVI and 0.2 g/g TS PDS. Protein removal, especially for tightly and loosely bound extracellular-polymeric-substance (EPS), is more linearly correlated to CST reduction than polysaccharide removal. Fecal sludge dewatering was improved by the hybrid functions of radical oxidation and iron coagulation. The ZVI/PDS treatment produced larger and looser flocs, probably because 1) surface ionic and hydrophilic groups of fecal sludge were reduced, 2) surface charge was neutralized, and 3) secondary structures of EPS proteins were altered by the radicals. The excellent fecal sludge dewatering was related to strengthened particle hydrophobicity and reduced sludge viscosity and compressibility. The results highlight that the ZVI/PDS combination is potentially an effective conditioning approach for fecal sludge from public toilets.
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Affiliation(s)
- Junxue Song
- College of Geography and Environment, Shandong Normal University, Jinan 250358, PR China; Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China
| | - Wei Fang
- Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China
| | - Jing Lai
- College of Geography and Environment, Shandong Normal University, Jinan 250358, PR China
| | - Bingdi Cao
- Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China
| | - Tao Zhang
- Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
| | - Zhenzhen Xu
- College of Geography and Environment, Shandong Normal University, Jinan 250358, PR China.
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6
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He X, He L, Lin Z, Zhou J, Shi S, Liu Y, Zhou J. Deep dewatering of activated sludge using composite conditioners of surfactant, acid and flocculant: The mechanism and dosage model. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150899. [PMID: 34656594 DOI: 10.1016/j.scitotenv.2021.150899] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/05/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
To address the problem of difficult disposal caused by poor dewaterability of high-organic sludge in wastewater treatment plant, this study developed a sludge composite conditioner (SCC) consisting of sodium dodecyl sulfate (SDS), HCl and FeCl3. It has the potential to significantly improve the dewaterability of the high-organic sludge with the VSS/MLSS of 80%. The moisture content (MC) and bound water content of sludge were reduced from 98.00 to 59.65% and from 3.42 to 0.91 g/g dry sludge (DS) after being conditioned, respectively. The surfactant (SDS) promoted the dissolution of extracellular polymeric substances (EPS). The acid (HCl) enhanced the decomposition of the sludge flocs, making the insoluble EPS peel off and turn into the liquid phase. As a result, total EPS decreased by 52.70% compared to the original sludge. In addition, due to the neutralization effect of protons and FeCl3, the Zeta potential increased remarkably from -13.80 mV to -1.72 mV and the dispersed sludge particles formed during EPS dissolution process were re-flocculated, which increased the average size of the sludge particles. The ratio of proteins (PN)/polysaccharides (PS) also increased from 1.69 to 3.81. And a quantitative model of optimum dosage of SCC agents based on the influence of the sludge PS, PN and EPS content has been established, aiming to determine the dosage of each conditioner according to the properties of target sludge. In general, the SCC provided an effective pathway for sludge deep dewatering.
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Affiliation(s)
- Xuejie He
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Lei He
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Ziyuan Lin
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Jiong Zhou
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Shuohui Shi
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Yi Liu
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Jian Zhou
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China.
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7
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Hu P, Shen S, Zhao D, Wei H, Ge J, Jia F, Zhang X, Yang H. The influence of hydrophobicity on sludge dewatering associated with cationic starch-based flocculants. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 296:113218. [PMID: 34246906 DOI: 10.1016/j.jenvman.2021.113218] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 06/25/2021] [Accepted: 07/01/2021] [Indexed: 06/13/2023]
Abstract
Coagulation/flocculation is an extensive and effective pretreatment technology for improving the sludge dewaterability. A series of hydrophobically associated cationic starch-based flocculants (CS-DMRs) with different degrees of hydrophobicity but similar charge densities were designed and synthesized. The CS-DMRs exhibited excellent sludge dewatering performance. The dewaterability of sludge increased with the hydrophobicity of the CS-DMRs, and the filter cake moisture content (FCMC) and specific resistance to filtration (SRF) could be reduced from 95.47% and 7.09 × 1012 m/kg to 79.26% and 2.258 × 1012 m/kg, respectively, at a constant pressure of 0.05 MPa after conditioned by the starch-based flocculant with the highest hydrophobicity at its optimal dose. Moreover, due to their amphiphilic structures, CS-DMRs could closely interact with the negatively charged extracellular polymeric substances (EPS), efficiently compress the protein and polysaccharide in EPS, and release the bound water. A second-order polynomial model was proposed according to the phenomenological theory to quantitatively analyze the effect of hydrophobicity in these starch-based flocculants on the sludge dewaterability. The structure-activity relationship was built, and the optimal dose and corresponding FCMC could be theoretically estimated accordingly. The results were in good agreement with the experimental results. The dewatering mechanisms were also discussed in detail on the basis of the changes in the FCMC, SRF, capillary suction time, properties of sludge flocs, compression coefficient, microstructures of sludge cakes, EPS fractions and components, and spatial distributions of the proteins and polysaccharides. In addition to charge neutralization, the hydrophobic association effects of CS-DMRs played an important role in the formation of drainage channels and net-like porous structures in the sludge cake to improve its permeability and filterability. This study thus provided a good understanding of the structural effects of the starch-based flocculants on the sludge dewaterability. The results are greatly beneficial to the fabrication and utilization of environment-friendly and high-performance natural polymeric conditioners for sludge treatment.
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Affiliation(s)
- Pan Hu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Shaohang Shen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Donghua Zhao
- Shanghai Waterway Engineering Design and Consulting Co., LTD., Shanghai, 200120, PR China
| | - Hua Wei
- Shanghai Waterway Engineering Design and Consulting Co., LTD., Shanghai, 200120, PR China
| | - Jun Ge
- Shanghai Waterway Engineering Design and Consulting Co., LTD., Shanghai, 200120, PR China
| | - Feiyue Jia
- Shanghai Waterway Engineering Design and Consulting Co., LTD., Shanghai, 200120, PR China
| | - Xiangxiang Zhang
- Shanghai Waterway Engineering Design and Consulting Co., LTD., Shanghai, 200120, PR China
| | - Hu Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China; Quanzhou Institute for Environmental Protection Industry, Nanjing University, Beifeng Road, Quanzhou, 362000, PR China.
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8
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Duan L, Zhou Z, Dai X. Conditioning of raw sludge and thermally hydrolyzed sludge by ferric salt and cationic polyacrylamide: rheological analysis. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2021; 83:1566-1577. [PMID: 33843743 DOI: 10.2166/wst.2021.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this study, the conditioning effect of cationic polyacrylamide (CPAM) with different charge densities on raw sludge (RS) and thermo-hydrolyzed sludge (HS) pretreated with or without ferric salt is studied through orthogonal experiments. In addition, this paper uses the principles of rheology and morphology to analyze and clarify the conditioning mechanism of RS and HS, and reveals the mechanism of thermal hydrolysis to improve the dewatering performance of sludge. Compared with the RS, the HS has smaller particle size, better filterability, stronger fluidity and more obvious thixotropy. However, due to the influence of filter pressing time, ferric salt should be added before conditioning. The orthogonal experiment shows that the optimal conditioner is CPAM with charge density of 60, and the specific resistance to filtration and capillary suction time of the adjusted thermo-hydrolyzed sludge are reduced to (1.11 ± 0.07) × 1012 m/kg and 16.1 ± 1.8 s; the particle size increased from 61.2 to 253.5 μm. The moisture content of the sludge cake is about 48%. The structural strength and thixotropy of HS are higher than those of the RS, and can be greatly improved by adding ferric salt. Morphological analysis confirms that thermal hydrolysis can lyse microbial cells in sludge, and the sludge treated with ferric salt will have more porous structure and stronger flocculation strength.
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Affiliation(s)
- Liqiang Duan
- College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China
| | - Zhen Zhou
- College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, China
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail:
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Hu P, Zhuang S, Shen S, Yang Y, Yang H. Dewaterability of sewage sludge conditioned with a graft cationic starch-based flocculant: Role of structural characteristics of flocculant. WATER RESEARCH 2021; 189:116578. [PMID: 33160239 DOI: 10.1016/j.watres.2020.116578] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/17/2020] [Accepted: 10/27/2020] [Indexed: 06/11/2023]
Abstract
Coagulation/flocculation is one of the most extensive and cost-effective pretreatments to improve the dewaterability of sludge in water treatment plants. In this study, three series of graft cationic starch (St)-based flocculants with distinct structural characteristics including charge density (CD), graft-chain length (L), and graft-chain distribution (N) were synthesized by graft copolymerization of [(2-methacryloyloxy-ethyl) trimethyl ammonium chloride] and acrylamide onto St backbone. The structural effects of these St-based flocculants on the sludge dewaterability have been quantitatively analyzed by using a second-order polynomial model according to phenomenological theory. The predicted dewatering performance and optimal dose were fully consistent with the experimental results. On the basis of this established model, the dewatering mechanisms were discussed in detail by combination of the analysis of the changes in filter cake moisture content, specific resistance of filtration, bound water content, compression coefficient, extracellular polymeric substances fractions and components, spatial distributions of proteins and polysaccharides, microstructures of sludge cake, and flocs properties in the dewatering process. This graft St-based flocculant, with the structural characteristics of high CD, long L, and low N, exhibited superior sludge dewaterability because of the enhanced charge neutralization and bridging flocculation effects. Among these three structural factors, CD played a more important role in improvement of sludge dewaterability than L and N due to the dominant effect of charge neutralization. This study provided a better understanding of structure-activity relationship of these grafting modified flocculants, which was of significant guidance for the exploit and design of novel and efficient flocculants for improvement of sludge dewaterability.
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Affiliation(s)
- Pan Hu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Shuhan Zhuang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Shaohang Shen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Yihan Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Hu Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
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10
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Maraschin M, Hedlund Ferrari KF, Carissimi E. Acidification and flocculation of sludge from a water treatment plant: New action mechanisms. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2020.117417] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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11
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Liu J, Jia S, Xu L, Zhu F, Ren S, Liu Y, Sun Z. Application of composite degradable modified starch-based flocculant on dewatering and recycling properties. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 82:2051-2061. [PMID: 33263583 DOI: 10.2166/wst.2020.464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Sludge dewatering is an important step for wastewater treatment. Composite degradable flocculant (CDF) was prepared by cationic polyacrylamide (PAM) grafting onto modified starch with a novel initiator, and characterized by Fourier transform infrared spectroscopy. The microstructure of flocculated sludge was characterized by scanning electron microscopy. The study investigated the properties of CDF compared to PAM, which showed that the prepared CDF exhibited a highly effective flocculation on sludge dewatering, a higher transmittance and chemical oxygen demand removal rate, and a lower value of effluent ammonia nitrogen and total phosphorus. The fermentation process was also analyzed by testing the performance of dewatered sludge (temperature, pH, ammonia nitrogen, E4/E6 (humic acid absorbance at 465 nm (E4) and 665 nm (E6))). The dehydrated sludge with CDF could be easily compressed into cakes by belt-filter for easy transportation and storage. With the continuous addition of CDF and PAM, the corresponding index of capillary suction time (CST) increased. Moreover, the total value of CST with CDF was low, showing a good dewaterability. In addition, the sludge index of pumping time and moisture content with CDF were low in contrast with PAM. Fermentation experiments demonstrated that sludge with CDF had a comparatively high temperature and low value of E4/E6. Such novel CDF shows enormous potential in wastewater treatment and sludge fermentation.
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Affiliation(s)
- Jianbo Liu
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Shibei District, Qingdao, China E-mail: ; Sinocore Biotechnology (Qingdao) Co., Ltd, 53# Zhengzhou Road, Qingdao, 266042, China
| | - Shouhao Jia
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Shibei District, Qingdao, China E-mail:
| | - Liming Xu
- Sinocore Biotechnology (Qingdao) Co., Ltd, 53# Zhengzhou Road, Qingdao, 266042, China
| | - Feifei Zhu
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Shibei District, Qingdao, China E-mail:
| | - Shan Ren
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Shibei District, Qingdao, China E-mail:
| | - Yuanfeng Liu
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Shibei District, Qingdao, China E-mail:
| | - Ziqi Sun
- Sinocore Biotechnology (Qingdao) Co., Ltd, 53# Zhengzhou Road, Qingdao, 266042, China
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12
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Brisolara KB, Gentile B, Puszykowski K, Bourgeois J. Residuals, sludge, and biosolids: Advancements in the field. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2020; 92:1541-1551. [PMID: 32668078 DOI: 10.1002/wer.1402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/06/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
Advancements in the field of residuals, sludge, and biosolids have been made in 2019. This review outlines the major contributions of researchers that have been published in peer-reviewed journals and conference proceedings throughout 2019 and includes brief summaries from over 125 articles. The review is organized in sections including life cycle and risk assessments; characteristics, quality, and measurement including micropollutants, nanoparticles, pathogens, and metals; sludge treatment technologies including dewatering, digestion, composting, and wetlands; disposal and reuse including adsorbents, land application and agricultural uses, nutrient recovery, and innovative uses; odor and air emissions; and energy issues.
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Affiliation(s)
- Kari B Brisolara
- Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Bailey Gentile
- Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Kate Puszykowski
- Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - John Bourgeois
- Louisiana State University Health Sciences Center, New Orleans, LA, USA
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13
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Fan X, Wang Y, Zhang D, Guo Y, Gao S, Li E, Zheng H. Effects of acid, acid-ZVI/PMS, Fe(II)/PMS and ZVI/PMS conditioning on the wastewater activated sludge (WAS) dewaterability and extracellular polymeric substances (EPS). J Environ Sci (China) 2020; 91:73-84. [PMID: 32172984 DOI: 10.1016/j.jes.2020.01.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/10/2020] [Accepted: 01/12/2020] [Indexed: 06/10/2023]
Abstract
The effects of four conditioning approaches: Acid, Acid-zero-valent iron (ZVI)/peroxydisulfate (PMS), Fe(II)/PMS and ZVI/PMS, on wastewater activated sludge (WAS) dewatering and organics distribution in supernatant and extracellular polymeric substances (EPS) layers were investigated. The highest reduction in bound water and the most WAS destruction was achieved by Acid-ZVI/PMS, and the optimum conditions were pH 3, ZVI dosage 0.15 g/g dry solid (DS), oxone dosage 0.07 g/g DS and reaction time 10.6 min with the reductions in capillary suction time (CST) and water content (Wc) as 19.67% and 8.49%, respectively. Four conditioning approaches could result in TOC increase in EPS layers and supernatant, and protein (PN) content in tightly bound EPS (TB-EPS). After conditioning, organics in EPS layers could migrate to supernatant. Polysaccharide (PS) was easier to migrate to supernatant than PN. In addition, Acid, Acid-ZVI/PMS or Fe(II)/PMS conditioning promoted the release of some polysaccharides containing ring vibrations v PO, v C-O-C, v C-O-P functional groups from TB-EPS. ESR spectra proved that both radicals of SO4-· and ·OH contributed to dewatering and organics transformation and migration. CST value of WAS positively correlated with the ratios of PN/PS in LB-EPS and total EPS, while it negatively correlated with TOC, PN content and PS content in TB-EPS, as well as PS content in supernatant and LB-EPS. BWC negatively correlated to zeta potential and TOC value, PN content, and HA content in supernatant.
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Affiliation(s)
- Xiaoyang Fan
- College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China
| | - Yili Wang
- College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China; Jinyun Forest Ecosystem Research Station, Beijing Forestry University, Beijing 100083, China.
| | - Daxin Zhang
- College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China
| | - Yajie Guo
- College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China
| | - Shihui Gao
- College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China
| | - Enrui Li
- College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China
| | - Huaili Zheng
- Key Laboratory of the Three Gorges Reservoir Regions Eco-Environment, State Ministry of Education, Chongqing University, Chongqing 400045, China
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14
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Ferasat Z, Panahi R, Mokhtarani B. Natural polymer matrix as safe flocculant to remove turbidity from kaolin suspension: Performance and governing mechanism. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 255:109939. [PMID: 31790872 DOI: 10.1016/j.jenvman.2019.109939] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 11/24/2019] [Accepted: 11/26/2019] [Indexed: 06/10/2023]
Abstract
Conventional flocculants bear environmental and health concerns which could be avoided by applying natural materials, particularly polysaccharide and glycoprotein-containing ones. In the present study, yeast cell wall (YCW), a natural polymer matrix, was used as natural flocculant. To prepare YCW, Saccharomyces cerevisiae was cultivated in bench scale fermenter. After characterization, YCW was employed as anionic flocculant in jar tests to remove turbidity from kaolin suspensions at different conditions where either alum or poly aluminum chloride (PAC) was coagulant. Generally, the lower coagulant consumption, higher turbidity removal or faster sedimentation was observed by using YCW as flocculant. The developed flocculant was more effective in the presence of PAC compared to alum. At best, by applying 300 mg/L YCW, the highest turbidity removals of 98 and 97% were achieved using 10 ppm PAC at pH 6.5 and 50 ppm alum at pH 7.5, respectively. The presence of the flocculant in the structure of the flocs was proved by FTIR analysis. The final pH of the treated suspensions was suitable for discharge purpose without the need for neutralization. The excess positive charge neutralization and bridging were the governing mechanism in coagulation-flocculation process. YCW with proper performance, GRAS designation and readily availability can be considered as natural alternative to chemical anionic flocculants where the process needs safe compounds.
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Affiliation(s)
- Zahra Ferasat
- Chemistry & Chemical Engineering Research Center of Iran (CCERCI), 14968-13151, Tehran, Iran
| | - Reza Panahi
- Chemistry & Chemical Engineering Research Center of Iran (CCERCI), 14968-13151, Tehran, Iran.
| | - Babak Mokhtarani
- Chemistry & Chemical Engineering Research Center of Iran (CCERCI), 14968-13151, Tehran, Iran
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