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Yan Y, Xu H, Wang Z, Chen H, Yang L, Sun Y, Zhao C, Wang D. Effect of surface functional groups of polystyrene micro/nano plastics on the release of NOM from flocs during the aging process. JOURNAL OF HAZARDOUS MATERIALS 2024; 472:134421. [PMID: 38718517 DOI: 10.1016/j.jhazmat.2024.134421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 04/18/2024] [Accepted: 04/24/2024] [Indexed: 05/30/2024]
Abstract
Currently, the hidden risk of microplastics in the coagulation process has attracted much attention. However, previous studies aimed at improving the removal efficiency of microplastics and ignored the importance of interactions between microplastics and natural organic matter (NOM). This study investigated how polystyrene micro/nano particles impact the release of NOM during the aging of flocs formed by aluminum-based coagulants Al13 and AlCl3. The results elucidated that nano-particles with small particle sizes and agglomerative states are more likely to interact with coagulants. After 7 years of floc aging, the DOC content of the nano system decreased by more than 40%, while the micron system did not change significantly. During coagulation, the benzene rings in polystyrene particles form complexes with electrophilic aluminum ions through π-bonding, creating new Al-O bonds. NOM tends to adsorb at micro/nano plastic interfaces due to hydrophobic interactions and conformational entropy. In the aging process, the structure of PS-Al13 or PS-AlCl3 flocs and the functional groups on the surface of micro/nano plastics control the absorption and release of organic matter through hydrophobic, van der Waals forces, hydration, and polymer bridging. In the system with the addition of nano plastics, several DBPs such as TCAA, DCAA, TBM, DBCM and nitrosamines were reduced by more than 50%. The reaction order of different morphological structures and surface functional groups of microplastics to Al13 and AlCl3 systems is aromatic C-H > C-OH > C-O > NH2 > aromatic CC > aliphatic C-H and C-O>H-CO> NH2 >C-OH> aliphatic C-H. The results provided a new sight to explore the effect of micro/nano plastics on the release of NOM during flocs aging.
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Affiliation(s)
- Yi Yan
- Chang' an University, Xi'an, Shaanxi 710061, China
| | - Hui Xu
- Guangxi Key Laboratory of Advanced Structural Materials and Carbon Neutralization, School of Materials and Environment, Guangxi Minzu University, Nanning, Guangxi 530006, China.
| | - Zijie Wang
- China Railway Design Corporation, Tianji 300308, China
| | - Hongni Chen
- Chang' an University, Xi'an, Shaanxi 710061, China
| | - Liwei Yang
- Chang' an University, Xi'an, Shaanxi 710061, China
| | - Yan Sun
- Chang' an University, Xi'an, Shaanxi 710061, China
| | - Chuanliang Zhao
- Chang' an University, Xi'an, Shaanxi 710061, China; State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Dongsheng Wang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang 310058, China
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Liu Z, Luo F, He L, Wang S, Wu Y, Chen Z. Physical conditioning methods for sludge deep dewatering: A critical review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 360:121207. [PMID: 38788408 DOI: 10.1016/j.jenvman.2024.121207] [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: 01/22/2024] [Revised: 04/17/2024] [Accepted: 05/18/2024] [Indexed: 05/26/2024]
Abstract
Sludge is an inevitable waste product of sewage treatment with a high water content and large volume, it poses a significant threat of secondary pollution to both water and the atmosphere without proper disposal. In this regard, dewatering has emerged as an attractive method in sludge treatment, as it can reduce the sludge volume, enhance its transportability and calorific value, and even decrease the production of landfill leachate. In recent years, physical conditioning methods including non-chemical conditioners or energy input alone, have been extensively researched for their potential to enhance sludge dewatering efficiency, such as thermal treatment, freeze-thaw, microwave, ultrasonic, skeleton builders addition, and electro-dewatering, as well as combined methods. The main objective of this paper is to comprehensively evaluate the dewatering capacity of various physical conditioning methods, and identify key factors affecting sludge dewatering efficiency. In addition, future research anticipated directions and outlooks are proposed. This work is expected to provide valuable insights for developing efficient, eco-friendly, and low-energy consumption techniques for deep sludge dewatering.
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Affiliation(s)
- Zhuo Liu
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Fang Luo
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Lingzhi He
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Siqi Wang
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yi Wu
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhuqi Chen
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
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Yan H, Xu L, Su J, Wei H, Li X. Synergistic promotion of sludge reduction by surfactant-producing and lysozyme-producing bacteria: Optimization and effect of Na . BIORESOURCE TECHNOLOGY 2024; 393:130065. [PMID: 37984671 DOI: 10.1016/j.biortech.2023.130065] [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: 10/19/2023] [Revised: 11/16/2023] [Accepted: 11/17/2023] [Indexed: 11/22/2023]
Abstract
To improve the efficiency of aerobic digestion, this investigation utilized the synergistic effect of lysozyme-producing strain YH14 and surfactant-producing strain ZXY4 to promote sludge hydrolysis, and added NaCl to enhance this promoting effect. The best performance in promoting sludge hydrolysis was achieved when the inoculum of functional bacteria was 12 % (inoculum ratio of strain YH14: strain ZXY4 = 1:3) and the dosage of NaCl was 5 g L-1, which caused an increase of 19.25 % in the SS removal rate and 2588.21 mg L-1 in the SCOD release, as compared with the control. Fluorescence region integral analysis shows that the synergy of two functional bacteria and NaCl can enhance the biodegradability of sludge. Protein secondary structure analysis shows that strain ZXY4 and Na+ cause the EPS structure to loosen, increasing the chances of lysozyme lysis of bacteria. Nucleotide metabolism, metabolism of other amino acids and membrane transport enhanced in a co-processing system.
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Affiliation(s)
- Huan Yan
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Liang Xu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Junfeng Su
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Hao Wei
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Xuan Li
- College of Environmental Science & Engineering, Yancheng Institute of Technology, Yancheng 224051, China
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Park Y, Jin S, Noda I, Jung YM. Continuing progress in the field of two-dimensional correlation spectroscopy (2D-COS): Part III. Versatile applications. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 284:121636. [PMID: 36229084 DOI: 10.1016/j.saa.2022.121636] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/30/2022] [Accepted: 07/12/2022] [Indexed: 06/16/2023]
Abstract
In this review, the comprehensive summary of two-dimensional correlation spectroscopy (2D-COS) for the last two years is covered. The remarkable applications of 2D-COS in diverse fields using many types of probes and perturbations for the last two years are highlighted. IR spectroscopy is still the most popular probe in 2D-COS during the last two years. Applications in fluorescence and Raman spectroscopy are also very popularly used. In the external perturbations applied in 2D-COS, variations in concentration, pH, and relative compositions are dramatically increased during the last two years. Temperature is still the most used effect, but it is slightly decreased compared to two years ago. 2D-COS has been applied to diverse systems, such as environments, natural products, polymers, food, proteins and peptides, solutions, mixtures, nano materials, pharmaceuticals, and others. Especially, biological and environmental applications have significantly emerged. This survey review paper shows that 2D-COS is an actively evolving and expanding field.
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Affiliation(s)
- Yeonju Park
- Kangwon Radiation Convergence Research Support Center, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Sila Jin
- Kangwon Radiation Convergence Research Support Center, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Isao Noda
- Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, USA.
| | - Young Mee Jung
- Kangwon Radiation Convergence Research Support Center, Kangwon National University, Chuncheon 24341, Republic of Korea; Department of Chemistry, and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea.
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5
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Novel insight into the degradation of polyacrylamide by thermophilic anaerobic digestion. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Zhang X, Zhang H, Liu T, Yang J, Wang Z, Chen P. Insights into the respective role of oxidation and flocculation conditioning for enhancing paper sludge dewaterability. Chem Eng Res Des 2022. [DOI: 10.1016/j.cherd.2022.06.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Sha L, Wu Z, Ling Z, Liu X, Yu X, Zhang S. Investigation on the improvement of activated sludge dewaterability using different iron forms (ZVI vs. Fe(II))/peroxydisulfate combined vertical electro-dewatering processes. CHEMOSPHERE 2022; 292:133416. [PMID: 34953873 DOI: 10.1016/j.chemosphere.2021.133416] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/08/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
The high moisture content (MC) of activated sludge dewatered by traditional vertical electro-dewatering (VED) is unable to meet the disposal requirements. Therefore, different iron forms (ZVI vs. Fe(II))/peroxydisulfate (PDS) combined VED (ZVI/PDS-VED and Fe(II)/PDS-VED) were employed to enhance the dewaterability of activated sludge. The dewatering behaviors of the two combined dewatering processes and the underlying mechanism related to the sludge characteristics were investigated and compared. Sludge was conditioned using ZVI/PDS and Fe(II)/PDS, respectively, and then dewatered by the VED in the experiment. Experimental results showed that with 0.3 g (g dry solids (DS))-1 of iron activators, 0.583 g (g DS) -1 of PDS, and 30 V of voltage, the MC of sludge after ZVI/PDS-VED and Fe(II)/PDS-VED reached the minimum values of 50.6 ± 1.2% and 32.1 ± 1.5%, respectively. ZVI/PDS and Fe(II)/PDS conditioning reduced the MC difference of sludge between the anode and the cathode during the VED, facilitating the water homogenization in the sludge cake. ZVI/PDS-VED and Fe(II)/PDS-VED could effectively reduce the bound water and the free water. Free water had high correlations with α-helix (r = 0.999, p < 0.05) and CO (r = 0.998, p < 0.05). Compared with the traditional VED and the ZVI/PDS-VED, the Fe(II)/PDS-VED had a greater improvement of sludge dewaterability due to the more efficient degradation of extracellular polymeric substances and the increase of sludge surface hydrophobicity. This study promoted the development of the new sludge deep-dewatering technology.
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Affiliation(s)
- Li Sha
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300354, China
| | - Zhangxiang Wu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300354, China
| | - Zichen Ling
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300354, China
| | - Xingxin Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300354, China
| | - Xiaoyan Yu
- School of Environmental and Safety Engineering, Taiyuan Institute of Technology, Taiyuan, 030008, China
| | - Shuting Zhang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300354, China.
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Liu X, Zhai Y, Liu G, Liu X, Wang B, Wang Z, Zhu Y, Fan Y, Shi H, Xu M. Mechanistic insights into enhanced waste activated sludge dewaterability with Cu(II) and Cu(II)/H 2O 2 treatment: Radical and non-radical pathway. CHEMOSPHERE 2022; 288:132549. [PMID: 34653483 DOI: 10.1016/j.chemosphere.2021.132549] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 09/30/2021] [Accepted: 10/10/2021] [Indexed: 06/13/2023]
Abstract
Without extra adjustment of pH, the effects of cupric ions (Cu(II)) and hydrogen peroxide (H2O2) alone or in combination on sludge dewatering were studied. It showed good dewatering capability after treated by Cu(II) and Cu(II)/H2O2, which indicated by the capillary suction times (CST) decreased from 120.8 ± 4.7 s (control) to about 40 s, and the water content (Wc) of sludge cake dropped by about 10%. The results showed that the extracellular polymeric substances (EPS) were destroyed, which characterized by a significant decrease in the biopolymers' concentrations in tightly-bound EPS. Meanwhile, more rough and porous microstructures and higher zeta potentials were obtained after conditioned. Based on the changes of physicochemical properties of sludge, the variations of EPS, and the identification of reactive species, two distinct mechanisms of improved sludge dewatering were postulated. As for Cu(II) treatment, it was mainly due to the surface charge neutralization, strong cytotoxicity of Cu(I) produced by intracellular reduction of Cu(II), and pH decline caused by Cu(II) hydrolysis that improved sludge dewatering performance, which could be noted as a "non-radical pathway". When in combination with H2O2, hydroxyl radicals (·OH) produced by Cu(II)-catalyzed Fenton-like process played a dominant role in degrading sludge flocs and EPS, which could be regarded as a "radical pathway".
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Affiliation(s)
- Xiaoping Liu
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, PR China
| | - Yunbo Zhai
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, PR China.
| | - Guangli Liu
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, PR China
| | - Xiangmin Liu
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, PR China
| | - Bei Wang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, PR China
| | - Zhexian Wang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, PR China
| | - Ya Zhu
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, PR China
| | - Yuwei Fan
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, PR China
| | - Haoran Shi
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, PR China
| | - Min Xu
- Chinese Academy of Environmental Planning, Beijing, 100012, PR China.
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Sun X, Wang G, Feng H, Miao X, Zhou S, Wang D, Huang L, Wang K. Preparation of sludge-based materials and their environmentally friendly applications in wastewater treatment by heterogeneous oxidation technology. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:332-348. [PMID: 34669132 DOI: 10.1007/s11356-021-16946-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
The sludge resource utilization and the high value-added development are environmentally friendly means for sludge treatment. With its rich organic substances and metals content, sludge can replace activated carbon and become a widely used carbon-based material, such as sludge-based activated carbon (SBAC). Meanwhile, as a heterogeneous catalyst, sludge-based catalyst (SBC) can solve the requirements of traditional Fenton catalysts for pH, metal ion leaching, and catalyst recycling. In this paper, combining the properties of SBAC/SBCs, the characteristics of the three methods of activation, support, and hydrothermal preparation of SBAC/SBCs are reviewed. In general, it is necessary to select an appropriate preparation method based on pollutants and environmental treatment goals. Furthermore, compared with other catalysts, SBC heterogeneous oxidation has obvious advantages in refractory organic pollutants. And the reaction mechanism usually involves SO4·-, ·OH, O2·-, and 1O2 processes. Finally, some possible directions for future research involving environmentally friendly SBAC/SBCs are proposed.
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Affiliation(s)
- Xiyu Sun
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China
| | - Guangzhi Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China.
| | - Huanzhang Feng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China
| | - Xinyi Miao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China
| | - Simin Zhou
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China
| | - Dongdong Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China
| | - Likun Huang
- School of Food Engineering, Harbin University of Commerce, Harbin, 150076, China
| | - Kun Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, China
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Zhang W, Chen J, Tang M, Wu H, Liu M, Ai J, Wang D. Citric acid chelated Fe(II) catalyzed peroxidation for simultaneously improving sludge dewaterability and antibiotic resistance genes (ARGs) removal. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2021.119925] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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11
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Biopolymer transformation and antibiotics degradation of wastewater sludge using thermally activated persulfate oxidation for dewaterability enhancement. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.119021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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12
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Cao B, Zhang T, Zhang W, Wang D. Enhanced technology based for sewage sludge deep dewatering: A critical review. WATER RESEARCH 2021; 189:116650. [PMID: 33246217 DOI: 10.1016/j.watres.2020.116650] [Citation(s) in RCA: 150] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/20/2020] [Accepted: 11/15/2020] [Indexed: 05/06/2023]
Abstract
Sludge is an inevitable by product of sewage treatment, and it includes pathogens, heavy metals, organic pollutants and other toxic substances. The components of sludge are complex and variable with extracellular polymeric substances (EPS) being one. EPS are highly hydrophilic and compressible, and make sludge dewatering difficult. Therefore, the development of efficient sludge-dewatering technology is an important means of mitigating rapid sludge growth. At present, the main methods used for sludge deep-dewatering technology are chemical preconditioning with high-pressure filtration and electrical mechanical dewatering. The selection of chemical preconditioning directly determines the final efficiency of the sludge-dewatering process. In this paper, we conduct a comprehensive review of the problems related to sludge dewatering and systematically summarise the impact of different chemical conditioning technologies on the efficiency of sludge dewatering. Furthermore, the characteristics of different enhanced dewatering technologies are evaluated and analysed for their adaptability and final disposal methods. We believe that this review can clarify the chemical conditioner mechanism to improve sludge dewatering, provide reference debugging information for the sludge-dewatering process and promote the development of efficient and environmentally friendly sludge-dewatering technology.
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Affiliation(s)
- Bingdi Cao
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Tao Zhang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Weijun Zhang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China.
| | - Dongsheng Wang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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Zhang W, Tang M, Li D, Yang P, Xu S, Wang D. Effects of alkalinity on interaction between EPS and hydroxy-aluminum with different speciation in wastewater sludge conditioning with aluminum based inorganic polymer flocculant. J Environ Sci (China) 2021; 100:257-268. [PMID: 33279038 DOI: 10.1016/j.jes.2020.05.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/13/2020] [Accepted: 05/14/2020] [Indexed: 06/12/2023]
Abstract
Extracellular polymeric substances (EPS) form a stable gel-like structure to combine with water molecules through steric hindrance, making the mechanical dewatering of wastewater sludge considerably difficult. Coagulation/flocculation has been widely applied in improving the sludge dewatering performance, while sludge properties (organic fraction and solution chemistry conditions) are highly changeable and have important effects on sludge flocculation process. In this work, the alkalinity effects on sludge conditioning with hydroxy-aluminum were comprehensively investigated, and the interaction mechanisms between EPS and hydroxy-aluminum with different speciation were unraveled. The results showed that the effectiveness of hydroxy-aluminum conditioning gradually deteriorated with increase in alkalinity. Meanwhile, the polymeric hydroxy-aluminum (Al13) and highly polymerized hydroxy-aluminum (Al30) were hydrolysed and converted into amorphous aluminum hydroxide (Al(OH)3), which changed the flocculation mechanism from charge neutralization and complexing adsorption to hydrogen bond interaction. Additionally, both Al13 and Al30 showed higher binding capacity for proteins and polysaccharides in EPS than monomeric aluminum and Al(OH)3. Al13 and Al30 coagulation changed the secondary structure of proteins in EPS, which caused a gelation reaction to increase molecular hydrophobicity of proteins and consequently sludge dewaterability. This study provided a guidance for optimizing the hydroxy-aluminum flocculation conditioning of sludge with high solution alkalinity.
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Affiliation(s)
- Weijun Zhang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China; Hubei Provincial Engineering Research Center of Systematic Water Pollution Control, Wuhan 430074, China
| | - Mingyue Tang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Dandan Li
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Peng Yang
- School of Civil and Architecture Engineer, Northeast Electric Power University, Jilin 132012, China.
| | - Shiwei Xu
- CECEP Engineering Technology Research Institution, Beijing 100082, China
| | - Dongsheng Wang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
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