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Yan A, Chen Y, Li N, Ma T, Qi Y, Xu D. Dewatering performance of aerobic granular sludge under centrifugal with different sludge conditioning agent. Front Microbiol 2024; 15:1386557. [PMID: 38952447 PMCID: PMC11215069 DOI: 10.3389/fmicb.2024.1386557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/29/2024] [Indexed: 07/03/2024] Open
Abstract
The aerobic granular sludge(AGS) technology draw scientific researchers attention, and more and more scientific research focuses on it, due to its superior advantages, such as good settling performance, high biological phase, high toxicity resistance and multiple biological effects. With the rapid development of AGS technology, a considerable amount of residual AGS will be produced, and dehydration is the biggest bottleneck of sludge reduction. This study investigated the dewatering process and method of residual AGS cultured by continuous flow experiment. Experiments were conducted using centrifugal dewatering technology with a dosing scheme to analyze the granular sludge dewatering process, and investigate the release process of EPS component in AGS dewatering. Our results implied the specific resistance of AGS has a very low value ((1.82 ± 0.03) × 109 m/kg) and it was not obvious for the conditioning effect of chemical conditioner on AGS dewatering. However, the moisture content can be reduced to 63.5% after dewatering with the presence of inorganic substances. The addition of drinking water treatment plant sludge (Alum sludge) can improve the efficiency of the dewatering of AGS. A possible dewatering process of AGS dewatering was proposed which was divided into two stages: First, a considerable amount of free water in the sludge was quickly removed under the action of gravity without pressure filtration. Second, the bound water release required cooperation between applying centrifugal or pressing force to grind granular cells and separate protein-like substances with the inorganic matter inside the granular sludge. The possible mechanism of AGS dewatering and hypothesis dewatering process are useful to optimize the AGS dewatering process.
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Affiliation(s)
- Ailan Yan
- Nanxun Innovation Institute, Zhejiang University of Water Resources and Electric Power, Hangzhou, China
- College of Water Conservancy and Environmental Engineering, Zhejiang University of Water Resources and Electric Power, Hangzhou, China
| | - Yongfei Chen
- Hangzhou Yongzhan Environment Technology Co., Ltd., Hangzhou, China
| | - Ningyu Li
- College of Water Conservancy and Environmental Engineering, Zhejiang University of Water Resources and Electric Power, Hangzhou, China
| | - Ting Ma
- China Railway Eryuan Engineering Group East China Exploration & Design Co., Ltd., Hangzhou, China
| | - Yiting Qi
- College of Water Conservancy and Environmental Engineering, Zhejiang University of Water Resources and Electric Power, Hangzhou, China
| | - Dong Xu
- College of Water Conservancy and Environmental Engineering, Zhejiang University of Water Resources and Electric Power, Hangzhou, China
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Hou J, Hong C, Ling W, Hu J, Feng W, Xing Y, Wang Y, Zhao C, Feng L. Research progress in improving sludge dewaterability: sludge characteristics, chemical conditioning and influencing factors. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 351:119863. [PMID: 38141343 DOI: 10.1016/j.jenvman.2023.119863] [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: 09/11/2023] [Revised: 11/29/2023] [Accepted: 12/12/2023] [Indexed: 12/25/2023]
Abstract
Sludge from wastewater treatment processes with high water content and large volume has become an inevitable issue in environmental management. Due to the challenging dewatering properties of sludge, current mechanical dewatering methods are no longer sufficient to meet the escalating water content standards of sludge. This paper summarizes the characteristics of various sludge and raises reasons for the their dewaterability differences. Affected by extracellular polymeric substances, biological sludge is hydrophilic and negatively charged, which limits the dewatering degree. The rheological properties, flocs, ionic composition, and solid phase concentration of the sludge also influence the dewatering to some extent. For these factors, the chemical conditioning measures with simple operation and excellent effect improve its dewaterability, which mainly include flocculation/coagulation, acid/alkali treatment, advanced oxidation, surfactant treatment and combined treatment. There is a growing necessity to explore the development of new chemical conditioning agents, even though traditional agents continue to remain widely used. However, the development of these new agents should prioritize finding a balance between various factors such as efficiency, effectiveness, ease of operation, environmental safety, and cost-effectiveness. Electrochemical dewatering enhances solid-liquid separation, and its coupling with chemical conditioning is also an excellent means to further reduce water content. In addition, the improvement of press filter is an effective way, which is influenced by pressure, processing time, sludge cake thickness and pore structure, filter media etc. In general, it is essential to develop new conditioning agents and enhance mechanical filtration press technology based on a thorough understanding of various sludge properties. Concurrently, an in-depth study of the principles of mechanical pressure filtration will contribute to establishing a theoretical foundation for effective deep sludge dewatering and propel further advancements in this field.
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Affiliation(s)
- Jiachen Hou
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Chen Hong
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Beijing, 100083, China.
| | - Wei Ling
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Jiashuo Hu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Weibo Feng
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yi Xing
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yijie Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Chengwang Zhao
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Lihui Feng
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
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Zeng Y, Wang Z, Pan Z, Shen L, Teng J, Lin H, Zhang J. Novel thermodynamic mechanisms of co-conditioning with polymeric aluminum chloride and polyacrylamide for improved sludge dewatering: A paradigm shift in the field. ENVIRONMENTAL RESEARCH 2023; 234:116420. [PMID: 37327838 DOI: 10.1016/j.envres.2023.116420] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 05/25/2023] [Accepted: 06/13/2023] [Indexed: 06/18/2023]
Abstract
This study investigated the combined effects of polymeric aluminum chloride (PAC) and polyacrylamide (PAM) on sludge dewatering, aiming to unveil underlying mechanisms. Co-conditioning with 15 mg g-1 PAC and 1 mg g-1 PAM achieved optimal dewatering, reducing specific filtration resistance (SFR) of co-conditioned sludge to 4.38 × 1012 m-1kg-1, a mere 48.1% of raw sludge's SFR. Compared with the CST of raw sludge (36.45 s), sludge sample can be significantly reduced to 17.7 s. Characterization tests showed enhanced neutralization and agglomeration in co-conditioned sludge. Theoretical calculations revealed elimination of interaction energy barriers between sludge particles post co-conditioning, converting sludge surface from hydrophilic (3.03 mJ m-2) to hydrophobic (-46.20 mJ m-2), facilitating spontaneous agglomeration. Findings explain improved dewatering performance. Based on Flory-Huggins lattice theory, connection between polymer structure and SFR was established. Raw sludge formation triggered significant change in chemical potential, increasing bound water retention capacity and SFR. In contrast, co-conditioned sludge exhibited thinnest gel layer, reducing SFR and significantly improving dewatering. These findings represent a paradigm shift, shedding new light on fundamental thermodynamic mechanisms of sludge dewatering with different chemical conditioning.
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Affiliation(s)
- Yansha Zeng
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, 321004, China.
| | - Zhe Wang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, 321004, China.
| | - Zhenxiang Pan
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, 321004, China.
| | - Liguo Shen
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, 321004, China.
| | - Jiaheng Teng
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, 321004, China.
| | - Hongjun Lin
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, 321004, China.
| | - Jianzhen Zhang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, 321004, China.
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Xu X, Wang W, Zhang Y, Meng Q, Huang T, Zhang W. Analysis on the properties of hydrolyzed amino acids in typical municipal sludge. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:60760-60767. [PMID: 37041356 DOI: 10.1007/s11356-023-26794-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/28/2023] [Indexed: 05/10/2023]
Abstract
In this study, amino acids, proteins, and microbial communities in sludge from different wastewater treatment plants (WWTPs) were analyzed. The results showed that the bacterial communities of different sludge samples were similar at the phylum level, and the dominant bacterial species in sludge samples with the same treatment process were the consistent. The main amino acids in EPS of different layers were different, and the amino acid results of different sludge samples were quite different, but the content of hydrophilic amino acids in all samples was higher than that of hydrophobic amino acids. And the total content of glycine, serine, and threonine related to sludge dewatering was positively correlated with protein content in sludge. In addition, the content of nitrifying bacteria and denitrifying bacteria in sludge was also positively correlated with the content of hydrophilic amino acids. In this study, the correlations between proteins, amino acids, and microbial communities in sludge were analyzed respectively, and the internal relationship was found. And it provided ideas for further study of sludge dewatering characteristics in the future.
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Affiliation(s)
- Xin Xu
- College of Energy and Environment, Shenyang Aerospace University, Shenyang, 110136, China
| | - Weiyun Wang
- College of Energy and Environment, Shenyang Aerospace University, Shenyang, 110136, China.
- Key Laboratory of Clean Energy of Liaoning, Shenyang, 110136, China.
| | - Yufang Zhang
- College of Energy and Environment, Shenyang Aerospace University, Shenyang, 110136, China
| | - Qingsi Meng
- College of Energy and Environment, Shenyang Aerospace University, Shenyang, 110136, China
| | - Tengda Huang
- College of Energy and Environment, Shenyang Aerospace University, Shenyang, 110136, China
| | - Wanli Zhang
- College of Energy and Environment, Shenyang Aerospace University, Shenyang, 110136, China
- Key Laboratory of Clean Energy of Liaoning, Shenyang, 110136, China
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5
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Dai Z, Liu L, Duan H, Li B, Tang X, Wu X, Liu G, Zhang L. Improving sludge dewaterability by free nitrous acid and lysozyme pretreatment: Performances and mechanisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 855:158648. [PMID: 36096212 DOI: 10.1016/j.scitotenv.2022.158648] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/05/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
Reducing the water content of waste activated sludge (WAS) is critical for sludge treatment and disposal in wastewater treatment plants (WWTPs). In this study, a new combined conditioning processes by using lysozyme (LZM) and free nitrous acid (FNA) were proposed and demonstrated to enhance the dewaterability of WAS. The water content of sludge cake dropped from 82.82 % to 68.42 % (1 h FNA treatment + 1 h LZM treatment) and 69.52 % (6 h FNA treatment + 1 h LZM treatment) with the combined FNA and LZM treatment; and the corresponding capillary suction time (CST) reduction efficiency increased 49.29 % (1 h FNA treatment + 1 h LZM treatment) and 52.98 % (6 h FNA treatment + 1 h LZM treatment). A comprehensive investigation conducted in this study revealed the underlying mechanism of dewaterability improvement lies in the transformations of extracellular polymeric substances (EPS). The combined conditioning led to enhanced hydrophobicity in the sludge, as suggested by FTIR protein secondary structure and interfacial free energy. The reduced zeta potential and the potential barrier indicated the reduction of the repulsive force of sludge particles and the bound water content in the conditioned floc. The hydrophobicity, flow permeability and flocculability were enhanced after combined treatment, leading to the release of bound water.
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Affiliation(s)
- Ziheng Dai
- School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety, MOE Key Laboratory of Theoretical Chemistry of Environment, Guangdong Provincial Engineering Technology Research Center for Wastewater Management and Treatment, South China Normal University, Guangzhou 510006, China
| | - Lei Liu
- School of Environment and Civil Engineering, Dongguan University of Technology, Dongguan 523808, China.
| | - Haoran Duan
- Australian Centre for Water and Environmental Biotechnology (ACWEB), The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Biqing Li
- Guangzhou sewage purification Co. Ltd., Guangzhou 510655, China
| | - Xia Tang
- Guangzhou sewage purification Co. Ltd., Guangzhou 510655, China
| | - Xuewei Wu
- Guangzhou sewage purification Co. Ltd., Guangzhou 510655, China
| | - Gang Liu
- School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety, MOE Key Laboratory of Theoretical Chemistry of Environment, Guangdong Provincial Engineering Technology Research Center for Wastewater Management and Treatment, South China Normal University, Guangzhou 510006, China
| | - Liguo Zhang
- School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety, MOE Key Laboratory of Theoretical Chemistry of Environment, Guangdong Provincial Engineering Technology Research Center for Wastewater Management and Treatment, South China Normal University, Guangzhou 510006, China.
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6
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Li G, Zhong H, Yang Y, Zhu L, Liu X, Wang H. Effect of modified kaolin conditioning sludge on organic matter properties. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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7
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Trend in Research on Characterization, Environmental Impacts and Treatment of Oily Sludge: A Systematic Review. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27227795. [PMID: 36431896 PMCID: PMC9695482 DOI: 10.3390/molecules27227795] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/08/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022]
Abstract
Oily sludge is a hazardous material generated from the petroleum industry that has attracted increasing research interest. Although several review articles have dealt with specific subtopics focusing on the treatment of oily sludge based on selected references, no attempt has been made to demonstrate the research trend of oily sludge comprehensively and quantitatively. This study conducted a systematic review to analyze and evaluate all oily sludge-related journal articles retrieved from the Web of Science database. The results show that an increase in oily sludge-related research did not take place until recent years and the distribution of the researchers is geographically out of balance. Most oily sludge-related articles focused on treatment for harmfulness reduction or valorization with limited coverage of formation, characterization, and environmental impact assessment of oily sludge. Pyrolytic treatment has attracted increasing research attention in recent years. So far, the research findings have been largely based on laboratory-scale experiments with insufficient consideration of the cost-effectiveness of the proposed treatment methods. Although many methods have been proposed, few alone could satisfactorily achieve cost-effective treatment goals. To enable sustainable management of oily sludge on a global scale, efforts need to be made to fund more research projects, especially in the major oil-producing countries. Pilot-scale experiments using readily available and affordable materials should be encouraged for practical purposes. This will allow a sensible cost-benefit analysis of a proposed method/procedure for oily sludge treatment. To improve the treatment performance, combined methods are more desirable. To inform the smart selection of methods for the treatment of different oily sludge types, it is suggested to develop universally accepted evaluation systems for characterization and environmental risk of oily sludge.
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Zhang X, Ye P, Wu Y. Enhanced technology for sewage sludge advanced dewatering from an engineering practice perspective: A review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 321:115938. [PMID: 35985273 DOI: 10.1016/j.jenvman.2022.115938] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/22/2022] [Accepted: 08/01/2022] [Indexed: 06/15/2023]
Abstract
The increasing production of sludge poses significant environmental risks. Sludge disposal and transport are costly because of the high water content (WC). Reducing the WC of sludge is the most efficient strategy to decrease treatment costs. However, the sludge contains a large amount of hydrophilic organic matter, causing poor dewaterability. Therefore, research on preconditioning and mechanical dewatering has great significance for advanced sludge dewatering. In this study, the features of sludge, the advantages and disadvantages of preconditioning methods, and the action mechanisms (including physical, chemical, and biological preconditioning) are thoroughly described. In addition, the dewatering principle and engineering applications of mechanical dewatering techniques are introduced in this manuscript, especially the application of vacuum preloading as an in-situ dewatering technology in sludge. Finally, cost analysis of different conditioning and mechanical dewatering methods is conducted to explore their application feasibility. This manuscript provides new insights for engineering applications of preconditioning methods and mechanical dewatering technology.
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Affiliation(s)
- Xudong Zhang
- Department of Civil Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China.
| | - Peng Ye
- Department of Civil Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China.
| | - Yajun Wu
- Department of Civil Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China.
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9
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Wang LY, Li X, Luo K, Song YH, Liu RG. Settleability and dewaterability of sewage sludge with modified diatomite. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:72159-72168. [PMID: 35460485 DOI: 10.1007/s11356-022-20368-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 04/17/2022] [Indexed: 06/14/2023]
Abstract
In this study, cationic polyacrylamide (CPAM)-modified diatomite and cetyl trimethyl ammonium bromide (CTAB)-modified diatomite were synthesized and used as conditioners for sewage sludge dewatering. The effects of these two types of modified diatomite on the dewaterability and settling performance of the activated sludge were studied. The mechanisms of the two modified diatomite types in the activated sludge system were elucidated. The efficiency of the CPAM-modified diatomite was better than that of the CTAB-modified diatomite in improving the settleability and dewaterability of sludge. The results indicated that specific resistance to filtration (SRF) was decreased from 8.52 × 1012 to 0.92 × 1012 m/Kg, and the water content in the remaining sludge cake after pumping filtration was decreased from 92.2 to 68.1% by adding 0.4% of CPAM-modified diatomite and pH = 3.5, which resulted in excellent sludge settling of activated sludge. Further studies showed that the polymer/surfactant adsorbed in diatomite increased sludge dewaterability and improved the sedimentation rate owing to stripping extracellular polymeric substances (EPS) and damaging the internal structure of the sludge, leading to sludge conduce bound water release. According to scanning electron microscope (SEM) images, the two types of modified diatomite powder maintained the porous structure and showed a more complete and uniform structure compared to natural diatomite.
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Affiliation(s)
- Ling-Yu Wang
- College of Biological and Environmental Engineering, Changsha University, Changsha, 410022, China
| | - Xue Li
- College of Biological and Environmental Engineering, Changsha University, Changsha, 410022, China.
| | - Kun Luo
- College of Biological and Environmental Engineering, Changsha University, Changsha, 410022, China
| | - Yu-Hao Song
- College of Biological and Environmental Engineering, Changsha University, Changsha, 410022, China
| | - Ren-Guo Liu
- College of Biological and Environmental Engineering, Changsha University, Changsha, 410022, China
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Hyrycz M, Ochowiak M, Krupińska A, Włodarczak S, Matuszak M. A review of flocculants as an efficient method for increasing the efficiency of municipal sludge dewatering: Mechanisms, performances, influencing factors and perspectives. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 820:153328. [PMID: 35074381 DOI: 10.1016/j.scitotenv.2022.153328] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
Mechanical sludge dewatering is one of the stages of the municipal wastewater treatment process, which allows the amount of generated sludge and the cost of its transport and management to be reduced. Achieving a high degree of dewatering is possible thanks to the use of flocculation technology. The article presents issues related to the theory of flocculation, sewage sludge, and its dewatering. The main mechanisms of flocculation, the kinetics of the process, the division of flocculants, and flocculation in dual systems are discussed. The influence of particular parameters on the efficiency of flocculation and the dewatering of sewage sludge was analyed. The assessed parameters are: pH, the presence of salt, the mixing process, the structure and ionicity of chains, and the dose. The results of experimental studies on the dewatering of various types of sludge were compared. The literature review included in the paper helps to better understand the process of flocculation and sludge dewatering, and presents the progress to date and the possible directions for further development in this field.
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Affiliation(s)
- Michał Hyrycz
- Department of Chemical Engineering and Equipment, Poznan University of Technology, 60-965 Poznan, Poland.
| | - Marek Ochowiak
- Department of Chemical Engineering and Equipment, Poznan University of Technology, 60-965 Poznan, Poland.
| | - Andżelika Krupińska
- Department of Chemical Engineering and Equipment, Poznan University of Technology, 60-965 Poznan, Poland.
| | - Sylwia Włodarczak
- Department of Chemical Engineering and Equipment, Poznan University of Technology, 60-965 Poznan, Poland.
| | - Magdalena Matuszak
- Department of Chemical Engineering and Equipment, Poznan University of Technology, 60-965 Poznan, Poland.
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Zhang Y, Li T, Tian J, Zhang H, Li F, Pei J. Enhanced dewaterability of waste activated sludge by UV assisted ZVI-PDS oxidation. J Environ Sci (China) 2022; 113:152-164. [PMID: 34963525 DOI: 10.1016/j.jes.2021.06.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 06/07/2021] [Accepted: 06/08/2021] [Indexed: 06/14/2023]
Abstract
Ultraviolet (UV) assisted zero-valent iron (ZVI)-activated sodium persulfate (PDS) oxidation (UV-ZVI-PDS) was used to treat waste activated sludge (WAS) in this study. The dewaterability performance and mechanism of WAS dewatering were analyzed. The results showed that UV-ZVI-PDS can obtain better sludge dewatering performance in a wide pH range (2.0-8.0). When the molar ratio of ZVI/PDS was 0.6, UV was 254nm, PDS dosage was 200 mg/g TS (total solid), pH was 6.54, reaction time was 20 min, the CST (capillary suction time) and SRF (specific resistance to filtration) were decreased by 64.0% and 78.2%, respectively. The molar ratio of ZVI/PDS used in this paper is much lower than that of literatures, and the contents of total Fe and Fe2+ in sludge supernatant remained at a low level, as 3.7 mg/L and 0.0 mg/L. The analysis of extracellular polymeric substances (EPS), scanning electron microscope (SEM) and particle size distribution showed that the EPS could be effectively destroyed by UV-ZVI-PDS, the sludge flocs broken down into smaller particles, cracks and holes appeared, and then the bound water was released. At the same time, the highly hydrophilic tightly bound-EPS (TB-EPS) were converted into loosely bound EPS (LB-EPS) and soluble EPS (S-EPS). During sludge pretreated by UV-ZVI-PDS, positively charged ions, such as Fe2+, Fe3+ and H+, produced in the reaction system could reduce the electronegativity of sludge surface, promote sludge particles aggregation, and then enhanced the sludge dewaterability.
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Affiliation(s)
- Yanping Zhang
- School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin 300401, China.
| | - Tiantian Li
- School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin 300401, China
| | - Jiayu Tian
- School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin 300401, China
| | - Huichun Zhang
- Department of Civil and Environmental Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Fen Li
- College of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150000, China
| | - Jiahua Pei
- School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin 300401, China
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Li X, Shi Y, Zhou X, Wang L, Zhang H, Pi K, Gerson AR, Liu D. Adaptability of organic matter and solid content to Fe 2+/persulfate and skeleton builder conditioner for waste activated sludge dewatering. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:14819-14829. [PMID: 34617233 DOI: 10.1007/s11356-021-16404-x] [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: 03/19/2021] [Accepted: 09/03/2021] [Indexed: 06/13/2023]
Abstract
Sludge conditioning is important for improved dewatering, with the sludge characteristics impacting the effect of conditioning. A composite conditioner, Fe2+-activated sodium persulfate (Fe2+/SPS) combined with phosphogypsum (PG), was used to examine its impact on sludges with different organic contents (34.6-43.8%) or different solid contents (2.8-5.9%). Response surface optimization analysis shows that when the best conditioning is achieved, the reduction of the specific resistance to filtration (SRF) is not sensitive to organic matter content, but the dewatering performance of the sludge is greatly affected by the solid content. The oxidation role of Fe2+/SPS and the skeleton builder role of PG together affect the conditioning, oxidation playing a major role in conditioning, especially for greater organic matter content. The organic content (maximum ηSOL value was 0.32) also affects the effectiveness of the skeleton builder more than the solid content (Maximum ηSOL value was 0.25). Changes in PG significantly impacts the optimal molar ratio and dosage of Fe2+/SPS. Sludge with greater solid content requires greater Fe2+/SPS dosage to provide stronger oxidation to destroy flocs, and the maximum Fe2+:SPS molar ratio was 1.14 with solid content of 5.9 wt%. The composite conditioning decreases the content of extracellular polymeric substances and proteins/polysaccharides. This study provides new insight into the relationship between the oxidation role of Fe2+/SPS and the skeleton builder role of PG for sludge conditioning strategies according to the optimal conditions.
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Affiliation(s)
- Xiaoran Li
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China
| | - Yafei Shi
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China.
- Hubei Key Laboratory of Ecological Restoration for River-Lakes and Algal Utilization, Wuhan, 430068, Hubei, China.
| | - Xi Zhou
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China
| | - Lu Wang
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China
| | - Huiqin Zhang
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China
| | - Kewu Pi
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China
- Hubei Key Laboratory of Ecological Restoration for River-Lakes and Algal Utilization, Wuhan, 430068, Hubei, China
| | - Andrea R Gerson
- Blue Minerals Consultancy, Wattle Grove, Tasmania, 7109, Australia
| | - Defu Liu
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China
- Hubei Key Laboratory of Ecological Restoration for River-Lakes and Algal Utilization, Wuhan, 430068, Hubei, China
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13
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Li L, Peng C, Deng L, Zhang F, Wu D, Ma F, Liu Y. Understanding the synergistic mechanism of PAM-FeCl 3 for improved sludge dewaterability. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 301:113926. [PMID: 34731962 DOI: 10.1016/j.jenvman.2021.113926] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 09/26/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
Hybrid flocculant polyacrylamide-ferric chloride (PAM-FeCl3) was developed to improve the dewaterability of sewage sludge and the dewatering performance, properties of treated sludge, composition and morphology distribution of extracellular polymeric substance (EPS) were investigated. The physicochemical properties of the PAM-FeCl3 were characterized, and its effectiveness as a sludge conditioner was evaluated. The results indicated that PAM-FeCl3 conditioning was able to promote sludge dewaterability. Simultaneously, PAM-FeCl3 neutralized the negative charges on the surface of sludge particles and increased the sludge floc size. Besides, PAM-FeCl3 also formed a rough and porous floc structure that reduced sludge compressibility. Meanwhile, the exciting emission matrix analysis suggested that PAM-FeCl3 can effectively disintegrate of EPS fraction in sludge and decompose the aromatic protein-like substances as well as the humic acid-like substances in EPS. Additionally, the larger sludge floc formation, electrostatic interaction and adsorption bridging effect resulted in compression of sludge structure and the decomposition of EPS fractions and improved sludge dewatering performance.
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Affiliation(s)
- Lixin Li
- School of Environmental and Chemical Engineering, Heilongjiang University of Science and Technology, Harbin, 150022, China; Longjiang Environmental Protection Group Co. Ltd, Harbin, 150050, China; State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150001, China.
| | - Cheng Peng
- School of Environmental and Chemical Engineering, Heilongjiang University of Science and Technology, Harbin, 150022, China
| | - Lihua Deng
- School of Environmental and Chemical Engineering, Heilongjiang University of Science and Technology, Harbin, 150022, China
| | - Fugui Zhang
- Longjiang Environmental Protection Group Co. Ltd, Harbin, 150050, China.
| | - Dan Wu
- Longjiang Environmental Protection Group Co. Ltd, Harbin, 150050, China
| | - Fang Ma
- State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150001, China
| | - Yan Liu
- College of Life Science and Technology, Harbin Normal University, Harbin, 150020, China
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14
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Wei L, Song Y, Tong K, Yuan S, Xie S, Shi L, Jia X, Geng X, Guo H. Compound Cleaning Agent for Oily Sludge from Experiments and Molecular Simulations. ACS OMEGA 2021; 6:33300-33309. [PMID: 34926882 PMCID: PMC8674908 DOI: 10.1021/acsomega.1c02286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 11/05/2021] [Indexed: 06/14/2023]
Abstract
This paper reported a new oily sludge compound cleaning agent formula, which used a combination of molecular simulation and experimental methods to study its interfacial formation energy (IFE), and exciting results were obtained. From a total of 24 surfactants in five categories, sodium silicate (Na2SiO3), sodium dodecylbenzene sulfonate, and fatty alcohol polyoxyethylene polyoxypropylene ether (JFC-SF) were screened out because of their excellent washing oil effect. Under a reasonable orthogonal system, when the mass ratio of the three surfactants was 3:1:1, the oil desorption effect was the best, the oil residual rate could reach 2.13%, and the oil removal efficiency could reach 93.53%. Verified by the molecular dynamics simulation module, the absolute value of the interface binding energy was the largest at this compound ratio, which was 465.71 kcal/mol. More importantly, we have discussed in depth the mechanism of adsorption and permeation of oily sludge by cleaning agents. Through single-factor influence experiments, the following optimized working condition parameters of the cleaning agent were determined: cleaning conditions with an agent content of 4%, a temperature of 70 °C, a stirring speed of 400 rpm, a cleaning time of 30 min, and a liquid-solid ratio (L/S) of 4:1. The research results laid the foundation for resource utilization, harmlessness, and reduction of oily sludge in the Liaohe oilfield.
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Affiliation(s)
- Lixin Wei
- State
Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety & Environment Technology, Beijing 100000, China
- Department
of Environment Technology, CNPC Research
Institute of Safety & Environment Technology, Beijing 100000, China
- School
of Petroleum Engineering, Northeast Petroleum
University, Daqing 163318, China
| | - Yang Song
- School
of Petroleum Engineering, Northeast Petroleum
University, Daqing 163318, China
| | - Kun Tong
- State
Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety & Environment Technology, Beijing 100000, China
- Department
of Environment Technology, CNPC Research
Institute of Safety & Environment Technology, Beijing 100000, China
| | - Shiling Yuan
- State
Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety & Environment Technology, Beijing 100000, China
- Department
of Environment Technology, CNPC Research
Institute of Safety & Environment Technology, Beijing 100000, China
- School
of Chemistry and Chemical Engineering, Shandong
University, Jinan 250013, China
| | - Shuixiang Xie
- State
Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety & Environment Technology, Beijing 100000, China
- Department
of Environment Technology, CNPC Research
Institute of Safety & Environment Technology, Beijing 100000, China
| | - Lijun Shi
- School
of Petroleum Engineering, Northeast Petroleum
University, Daqing 163318, China
| | - Xinlei Jia
- School
of Petroleum Engineering, Northeast Petroleum
University, Daqing 163318, China
- College
of Chemical Engineering and Safety, Binzhou
University, Binzhou 256600, China
| | - Xiaoheng Geng
- State
Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety & Environment Technology, Beijing 100000, China
- Department
of Environment Technology, CNPC Research
Institute of Safety & Environment Technology, Beijing 100000, China
- College
of Chemical Engineering and Safety, Binzhou
University, Binzhou 256600, China
| | - Haiying Guo
- State
Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety & Environment Technology, Beijing 100000, China
- Department
of Environment Technology, CNPC Research
Institute of Safety & Environment Technology, Beijing 100000, China
- College
of Chemical Engineering and Safety, Binzhou
University, Binzhou 256600, China
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15
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Bei Li Y, Li Song J, Jing Yao Q, Xu Chen Z, Wei Y, Long Li H, Xiao Wang M, Jing Wang B, Min Zhou J. Effects of dissolved oxygen on the sludge dewaterability and extracellular polymeric substances distribution by bioleaching. CHEMOSPHERE 2021; 281:130906. [PMID: 34029968 DOI: 10.1016/j.chemosphere.2021.130906] [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: 11/25/2020] [Revised: 05/11/2021] [Accepted: 05/13/2021] [Indexed: 06/12/2023]
Abstract
Bioleaching is a biological conditioning technology for sludge, which not only improves sludge dewatering performance but also removes heavy metals from sludge. As the bioleaching process is a comprehensive biological and chemical process, it is necessary to explore the effects of dissolved oxygen (DO) concentrations on bioleaching efficiency. Three bioleaching experiments with different DO concentrations (T1: 0.8-3.1 mg/L, T2: 3.1-5.5 mg/L, T3: 5.5-7.5 mg/L) were conducted for five days. The sludge dewatering efficiency was evaluated using capillary suction time (CST) and specific resistance to filtration (SRF). The relationship between sludge dewaterability and extracellular polymeric substance (EPS) fraction distribution was investigated. In the treatment with the highest DO concentration, the minimum values of SRF and CST were 4.31 × 1011 m/kg and 13.5 s, which occurred earlier than the treatment with the lower DO concentrations by approximately 24-48 h. A significant decrease (83.4-93.2%) in tightly bound EPS (TB-EPS) protein (PN) was observed in all treatments, while a positive correlation (r = 0.924, P < 0.01) was observed between SRF and PN content in TB-EPS. A relatively higher abundance of Acidithiobacillus was found with the increase in DO concentration. Additionally, other genera including Metallibacterium, Alicyclobacillus, Acidibacter, Acidocella, and Luteococcus also played important roles in EPS biodegradation. These results revealed that increasing the DO concentration could improve sludge dewatering performance and heavy metal removal by enhancing bioleaching microbial activity, the degradation of PN in TB-EPS, and sludge floc fragmentation, but only if sufficient energy sources were provided.
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Affiliation(s)
- Yun Bei Li
- School of Environment, Henan Normal University, China; Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, China; Henan Key Laboratory for Environmental Pollution Control, China.
| | - Jun Li Song
- School of Environment, Henan Normal University, China
| | - Qian Jing Yao
- School of Environment, Henan Normal University, China
| | - Ze Xu Chen
- School of Environment, Henan Normal University, China
| | - Yi Wei
- School of Environment, Henan Normal University, China
| | - Hai Long Li
- School of Environment, Henan Normal University, China
| | | | | | - Jia Min Zhou
- School of Environment, Henan Normal University, China
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16
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He D, Bao B, Sun M, Chen J, Luo H, Li J. Enhanced dewatering of activated sludge by acid assisted Heat-CaO 2 treatment: Simultaneously removing heavy metals and mitigating antibiotic resistance genes. JOURNAL OF HAZARDOUS MATERIALS 2021; 418:126248. [PMID: 34111741 DOI: 10.1016/j.jhazmat.2021.126248] [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: 02/28/2021] [Revised: 04/28/2021] [Accepted: 05/25/2021] [Indexed: 06/12/2023]
Abstract
High water content and accumulation of heavy metals and antibiotic resistance genes (ARGs) in sewage sludge limit its application. Fenton process has been widely used in sludge dewatering, but the use of hydrogen peroxide (H2O2) and generation of acid sludge are the main drawbacks. Here, a novel method of heat-CaO2 treatment was proposed to enhance sludge dewatering. Results showed that CaO2 (12.5 mg/g dry solids (DS)) combined with heat at 60 °C significantly improved the sludge dewaterability, e.g. the water content decreased from 79.9% to 69.2% and the specific resistance to filtration (SRF) decreased from 9.21 × 1013 to 1.51 × 1013 m/kg. At 62.5 mg CaO2/g DS, the final pH of filtrate was close to neutral and the good dewatering performance was still achieved. The improvement of sludge dewaterability was closely correlated with the decomposition of tightly-bound extracellular polymeric substances (EPS), lysis of the sludge cells, and increased particle size of the flocs. The distribution of bacterial community in the sludge has changed, leading to the decreases in the percentage of some ARGs. The concentrations of typical heavy metals wrapped in the sludge colloid network dramatically reduced. Economic analyses showed that the heat-CaO2 treatment was a promising method for sludge disposal.
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Affiliation(s)
- Dongqin He
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Bo Bao
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Mingkai Sun
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jingyi Chen
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Hongwei Luo
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jun Li
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
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17
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Lan B, Jin R, Liu G, Dong B, Zhou J, Xing D. Improving waste activated sludge dewaterability with sodium periodate pre-oxidation on extracellular polymeric substances. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2021; 93:1680-1689. [PMID: 33713351 DOI: 10.1002/wer.1553] [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: 10/18/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 05/21/2023]
Abstract
The efficiency of sludge dewatering is affected by the structure and composition of hydrated extracellular polymeric substances (EPS). Degrading EPS can improve the sludge dewatering performance. As an oxidizing agent, sodium periodate (NaIO4 ) has ability to oxidize organics, which is expected to decompose the protein and polysaccharide in EPS and improve the efficiency of sludge dewaterability. This study adopted NaIO4 , for the first time, as an advanced oxidation agent to regulate EPS of waste activated sludge and was combined with anionic polyacrylamide (APAM) as a flocculant to subsequently enhance sludge dewatering. Response surface methodology (RSM) was used to determine the optimal conditions of pH, NaIO4 , and APAM. The results showed that the composite conditioner's specific resistance of filtration (SRF) and the water content of the vacuum-filtered cake (Wc) were highly enhanced compared with those of the raw sludge (RS) under pH 6.5, a NaIO4 concentration of 50 mg/g dry solids (DS), and an APAM concentration of 5 mg/g DS. Owing to the pre-oxidation achieved by NaIO4 under a mildly acid environment, sludge flocs were broken. Subsequently, chemical coagulation (APAM) agglomerated the smaller particles into larger flocs of sludge by adsorption and bridging, thus improving sludge dewaterability. PRACTITIONER POINTS: A novel conditioner, pH/NaIO4 /APAM, was explored for sludge dewatering. IO3 • and HO• oxidized extracellular polymeric substances (EPS). Degradation of the protein content of EPS released bound water. Highly enhanced sludge dewaterability was achieved under optimal conditions.
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Affiliation(s)
- Bingbing Lan
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, China
| | - Ruofei Jin
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, China
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - Guangfei Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, China
| | - Bin Dong
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, China
| | - Jiti Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, China
| | - Defeng Xing
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
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18
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Ranjbar F, Karrabi M, Danesh S, Gheibi M. Improvement of wastewater sludge dewatering using ferric chloride, aluminum sulfate, and calcium oxide (experimental investigation and descriptive statistical analysis). WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2021; 93:1138-1149. [PMID: 33522044 DOI: 10.1002/wer.1526] [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: 09/27/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 06/12/2023]
Abstract
In this research, application of chemical conditioners for the conditioning of sludge and their effects on the improvement of sludge thickening of the wastewater treatment plant in the city of Bojnourd (Iran) is investigated. The concentration of chemical conditioners, pH and coagulation and flocculation time is from among the parameters studied in this research work. The results obtained indicate that sludge volume reduction for the chemical conditioners used, including Ferric Chloride (FeCl3 ), Aluminum Sulfate (Al2 (SO4 )3 ), and Calcium Oxide (CaO) are 41, 17, and 33 percent, respectively. The optimal concentration for FeCl3 , Al2 (SO4 )3, and CaO are 550, 1100, and 292 mg/L, respectively, and the optimal values of pH are 9, 7.5, and 10, respectively. The time to filtration (TTF) and reduction in sludge moisture content (SMC) for Ferric Chloride, Aluminum Sulfate, and Calcium Oxide are 45 s and 6.2%, 135 s and 3.3%, 190 s and 2.4% respectively. PRACTITIONER POINTS: Investigating the sludge conditioning by Ferric Chloride, Aluminum Sulfate, and Calcium Oxide. Determining the optimal concentration, pH, and coagulation/flocculation time. Calculating the time to filtration (TTF) and reduction in sludge moisture content (SMC). Predicting the settled sludge volume using descriptive statistical analysis.
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Affiliation(s)
- Flora Ranjbar
- Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mohsen Karrabi
- Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Shahnaz Danesh
- Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mohammad Gheibi
- Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
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19
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Wang J, Meng X, Chen Y, Zheng G, Zhou L. Simultaneously attenuating antibiotic resistance genes and improving the dewaterability of sewage sludge by conditioning with Fenton's reagent: the pivotal role of sludge pre-acidification. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:13300-13311. [PMID: 33175353 DOI: 10.1007/s11356-020-11562-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 11/05/2020] [Indexed: 06/11/2023]
Abstract
Fenton conditioning processes have been recently employed to improve the dewaterability of sewage sludge. However, it remains unclear whether the conditioning with Fenton's reagent would simultaneously attenuate antibiotic resistance genes (ARGs) in sludge and improve sludge dewaterability. It was found in the present study that sludge pre-acidification played a pivotal role in simultaneously removing ARGs and improving sludge dewaterability by conditioning with Fenton's reagent. When the sewage sludge was pre-acidified to pH = 3.0 and was then conditioned using Fenton's reagent, the absolute abundances of the total ARGs and the total mobile genic elements (MGEs) in conditioned sludge were reduced by 1.85-2.10 and 2.84-3.12 log units, respectively. Additionally, sludge capillary suction time (CST) and specific resistance to filtration (SRF) were drastically reduced, and the moisture content (MC) in dewatered sludge cake was reduced to only 60.61-69.95%. Such effective attenuation of ARGs and MGEs in conditioned sludge led to their removal in both the dewatered sludge cakes and dewatering filtrate. However, only the improvement of sludge dewaterability was attained by sludge conditioning with Fenton's reagent but without sludge pre-acidification. During the conditioning treatment, the removal of loosely bound extracellular polymeric substance (EPS) and tightly bound EPS in conditioned sludge contributed to the improvement of sludge dewaterability, and the damage of sludge microbial cells was highly correlated with the attenuation of antibiotic resistance. Thus, sludge pre-acidification combined with conditioning using Fenton's reagent can be employed to simultaneously attenuate the antibiotic resistance in sewage sludge and improve sludge dewaterability.
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Affiliation(s)
- Jiajun Wang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xiaoqing Meng
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yu Chen
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Guanyu Zheng
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, 210095, China.
- Department of Environmental Engineering, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
| | - Lixiang Zhou
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
- Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, 210095, China
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20
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The disintegration of excess sludge enhanced by short-term interaction with potassium ferrate: Characteristics and mechanism. J Taiwan Inst Chem Eng 2020. [DOI: 10.1016/j.jtice.2020.12.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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21
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Guo Z, Ma L, Dai Q, Ao R, Liu H, Wei Y, Mu L. Role of extracellular polymeric substances in sludge dewatering under modified corn-core powder and sludge-based biochar pretreatments. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 202:110882. [PMID: 32619891 DOI: 10.1016/j.ecoenv.2020.110882] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 06/07/2020] [Accepted: 06/08/2020] [Indexed: 06/11/2023]
Abstract
Extracellular polymeric substances (EPS) which wrapped on sludge particles were deemed to hinder the outflowing of combined water in sludge system. The complex composition of EPS was the bottleneck for revealing its relationship with sludge dewaterability. In this study, a combined modified corn-core powder (MCCP) and sludge-based biochar (SBB) condition was executed to treat sludge for enhancing dehydration performance, and the concentration and the form distribution of organics in EPS, the variances of protein secondary structures were investigated. Correlation between the sludge dewaterability and EPS components were performed, found strong correlations among the net sludge solids yield (YN) and the specific resistance of filtration (SRF) (R = -0.923), Zeta potential (R = -0.971). Furthermore, the relationship between the secondary structures of protein and dehydration performance were strong related. With the optimal dosage of SBB and MCCP, aggregated strands and α -helix were released, indicated that the unfolding and despiralization in soluble EPS (S-EPS) were improved, disordered the sludge network, reduced the flowing resistance of bound water, finally enhancing sludge dewaterability.
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Affiliation(s)
- Zhiying Guo
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China
| | - Liping Ma
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China.
| | - Quxiu Dai
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China
| | - Ran Ao
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China
| | - Hongpan Liu
- College of Chemistry and Environmental Engineering, Chongqing Key Laboratory of Environmental Materials & Remediation Technologies, Chongqing University of Arts and Sciences, Chongqing, 402160, China
| | - Yi Wei
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China
| | - Liusen Mu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China
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22
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Sang W, Li X, Feng Y, Zhang Q, Li D. Improvement of the sludge flocculation dewatering efficient by electromagnetic wave loading: research based on removal of bound water. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:3413-3427. [PMID: 31845252 DOI: 10.1007/s11356-019-07141-3] [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: 08/30/2019] [Accepted: 11/20/2019] [Indexed: 06/10/2023]
Abstract
Excess sludge was loaded by 2450 MHz electromagnetic wave in this study. The mechanism of electromagnetic wave loading on the releasing of bound water before sludge flocculation dewatering was investigated through observing the changes of extracellular polymeric substances (EPS) composition, surface charge, and particle size distribution. The results showed that the 8.55 g/g total suspended solids (TSS) of bound water was reduced with 160 J/mL electromagnetic wave, and the moisture content of sludge decreased by 3.02%. The EPS structure in the sludge floc matrix was destroyed and the LB-EPS content reduced. Simultaneously, infrared spectrum analysis indicated that bound water content was correlated both to the changes of hydrophilic and hydrophobic functional groups. Moreover, protein secondary structure analysis found that looser protein structure facilitated the exposure of internal hydrophobic groups and further promoted the sludge hydrophobic properties. Additionally, electromagnetic wave disintegrated colloidal stability through dipole motion. The zeta potential increased from - 25.57 to - 14.32 mV; the medium particle size (d0.5) decreased from 119.99 to 80.41 μm. More small molecules created in the supernatant were helpful to release bound water, which could further improve flocculation dewaterability of sludge with electromagnetic wave loading.
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Affiliation(s)
- Wenjiao Sang
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, China.
| | - Xiaoyang Li
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, China
| | - Yijie Feng
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, China
| | - Qian Zhang
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, China
| | - Dong Li
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, China
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