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Xiong Y, Lai J, Liu Z, Song M. Synergetic conditioning via oxalic acid enhanced Fe 2+/CaO 2 and skeleton construct to achieve deep dewatering of sewage sludge. CHEMOSPHERE 2024; 358:142115. [PMID: 38657689 DOI: 10.1016/j.chemosphere.2024.142115] [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: 12/28/2023] [Revised: 03/17/2024] [Accepted: 04/21/2024] [Indexed: 04/26/2024]
Abstract
Extracellular polymeric substance (EPS) with highly hydrophilic groups and sludge with high compressibility are determined sludge dewaterability. Herein, Fe2+ catalyzed calcium peroxide (CaO2) assisted by oxalic acid (OA) Fenton-like process combined with coal slime was applied to improve sludge dewaterability. Results demonstrated that the sludge treated by 0.45/1/1.1-OA/Fe2+/CaO2 mM/g DS, the water content (WC), specific resistance to filtration and capillary suction time dropped to 53.01%, 24.3 s and 1.2 × 1012 m/kg, respectively. Under coal slime ratio as 0.6, WC and compressibility were further reduced to 42.72% and 0.66, respectively. The hydroxyl radicals generated by OA/Fe2+/CaO2 under near-neutral pH layer by layer collapsed EPS, resulting in the degradation and migration of inner releasing components and the exposure of inner sludge flocs skeleton. The hydrophilic tryptophan-like protein of TB-EPS were degraded into aromatic protein of S-EPS and exposed inner hydrophobic sites. The protein secondary structures were transformed by destroying hydrophilic functional groups, which were attributed to the reducing α-helix ratio and reconstructing β-sheet. Moreover, coal slime as the skeleton builder lowered compressibility and formed more macropores to increase the filterability of pre-oxidized sludge for the higher intensity of rigid substances. This study deepened the understanding of OA enhanced Fenton-like system effects on sludge dewaterability and proposed a cost-effective and synergistic waste treatment strategy in sludge dewatering.
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Affiliation(s)
- Yun Xiong
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu, 210096, China
| | - Jiahao Lai
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu, 210096, China
| | - Zonghao Liu
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu, 210096, China
| | - Min Song
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu, 210096, China.
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Bao P, Du C, Li Y, Jiang H, Zhou L, Yu G, Sun S, Zhou L, Li X, Teng J, Wang X, Wang J. Application of skeleton builders to sludge dewatering and disposal: A critical review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167106. [PMID: 37717769 DOI: 10.1016/j.scitotenv.2023.167106] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 09/13/2023] [Accepted: 09/13/2023] [Indexed: 09/19/2023]
Abstract
With the development of cities and population, the production of sludge is increasing annually. It has become an unavoidable challenge to achieve sludge dewatering and disposal by a cost-effective, efficient and safe process. In this work, firstly, the factors limiting sludge dewatering are reviewed in terms of moisture distribution, sludge concentration, organic matter content, electronegativity, floc strength, and extracellular polymers (EPS). Subsequently, focusing on the dewatering technology about the skeleton builder, the recent progress of it is detailed in terms of mechanism, evaluation indicators, influencing factors, and technology coupling. In addition, the impact of skeleton builders on the sludge disposal stage is concluded. Finally, the challenges faced by sludge dewatering and skeleton builders are prospected. This review will provide some theoretical basis and technical guidance for subsequent experiments and practices regarding skeleton builders.
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Affiliation(s)
- Purui Bao
- School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410114, China
| | - Chunyan Du
- School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410114, China; Engineering Technology Research Center of Hunan Dongting Lake Flood Control and Water Resources Protection of Hunan Province, Hunan Water Resources and Hydropower Survey, Design, Planning and Research Co., Ltd, Changsha 410007, China; Engineering and Technical Center of Hunan Provincial Environmental Protection for River Lake Dredging Pollution Control, Changsha 410114, China.
| | - Yifu Li
- School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410114, China; Engineering and Technical Center of Hunan Provincial Environmental Protection for River Lake Dredging Pollution Control, Changsha 410114, China.
| | - Heng Jiang
- Engineering Technology Research Center of Hunan Dongting Lake Flood Control and Water Resources Protection of Hunan Province, Hunan Water Resources and Hydropower Survey, Design, Planning and Research Co., Ltd, Changsha 410007, China
| | - Lu Zhou
- School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410114, China; Engineering and Technical Center of Hunan Provincial Environmental Protection for River Lake Dredging Pollution Control, Changsha 410114, China
| | - Guanlong Yu
- School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410114, China; Engineering and Technical Center of Hunan Provincial Environmental Protection for River Lake Dredging Pollution Control, Changsha 410114, China
| | - Shiquan Sun
- School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410114, China; Engineering and Technical Center of Hunan Provincial Environmental Protection for River Lake Dredging Pollution Control, Changsha 410114, China
| | - Lean Zhou
- School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410114, China; Engineering and Technical Center of Hunan Provincial Environmental Protection for River Lake Dredging Pollution Control, Changsha 410114, China
| | - Xue Li
- School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410114, China
| | - Junyi Teng
- School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410114, China
| | - Xiaowen Wang
- School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410114, China
| | - Junchao Wang
- School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha 410114, China
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Su N. Spherical Polyelectrolyte Brushes as Flocculants and Retention Aids in Wet-End Papermaking. Molecules 2023; 28:7984. [PMID: 38138474 PMCID: PMC10745445 DOI: 10.3390/molecules28247984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/02/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
As the criteria of energy conservation, emission reduction, and environmental protection become more important, and with the development of wet-end papermaking, developing excellent retention aids is of great significance. Spherical polyelectrolyte brushes (SPBs) bearing polyelectrolyte chains grafted densely to the surface of core particle have the potential to be novel retention aids in wet-end papermaking not only because of their spherical structure, but also due to controllable grafting density and molecular weight. Such characteristics are crucial in order to design multi-functional retention aids in sophisticated papermaking systems. This review presents some important recent advances with respect to retention aids, including single-component system and dual-component systems. Then, basic theory in papermaking is also briefly reviewed. Based on these advances, it emphatically describes spherical polyelectrolyte brushes, focused on their preparation methods, characterization, conformation, and applications in papermaking. This work is expected to contribute to improve a comprehensive understanding on the composition, properties, and function mechanisms of retention aids, which helps in the further investigation on the design of novel retention aids with excellent performance.
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Affiliation(s)
- Na Su
- Department of Printing and Packaging Engineering, Shanghai Publishing and Printing College, Shanghai 200093, China
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Guo Z, Ma L, Dai Q, Liu Y, Zhang D, Ao R. Behavior of heavy metals in municipal sludge during dewatering: The role of conditioners and extracellular polymeric substances. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 342:118287. [PMID: 37269725 DOI: 10.1016/j.jenvman.2023.118287] [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: 10/23/2022] [Revised: 05/23/2023] [Accepted: 05/26/2023] [Indexed: 06/05/2023]
Abstract
Heavy metals, the main harmful substances in the sludge, are easily enriched, have adverse effects on the treatment and disposal of the sludge. In this study, two conditioners (modified corn-core powder, MCCP, and sludge-based biochar, SBB) were separately added and jointly added into municipal sludge to enhance sludge dewaterability. Meanwhile, diverse organics, such as extracellular polymeric substances (EPS), were released under pretreatment. The different organics had different effects on each heavy metal fraction and changed the toxicity and bioavailability of the treated sludge. The exchangeable fraction (F4) and carbonate fraction (F5) of heavy metal were nontoxic and nonbioavailable. When MCCP/SBB was used to pretreat the sludge, the ratio of metal-F4 and -F5 decreased, indicating that MCCP/SBB reduced the biological availability and ecological toxicity of the heavy metals in the sludge. These results were consistent with the calculation of the modified potential ecological risk index (MRI). To understand the detailed function of organics in the sludge network, the relationship between EPS, the secondary structure of the protein, and heavy metals was analyzed. The analyses revealed that the increasing proportion of β-sheet in soluble EPS (S-EPS) generated more active sites in the sludge system, which enhanced the chelate or complex function among organics and heavy metals, thus reducing the migration risks.
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Affiliation(s)
- Zhiying Guo
- College of Biological and Agricultural Sciences, Honghe University, Mengzi, 661199, 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.
| | - Yanhong Liu
- College of Biological and Agricultural Sciences, Honghe University, Mengzi, 661199, Yunnan, China
| | - Degang Zhang
- College of Biological and Agricultural Sciences, Honghe University, Mengzi, 661199, Yunnan, China
| | - Ran Ao
- College of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang, 550025, China
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Xia T, Zhang X, Chen D, Gao Z, Ji Y, Xia J, Wang L. Effects of ceramsite derived from sewage sludge combined with the O 3-FeCl 3/PAM process on the dewatering of waste-activated sludge and investigation of dewatering mechanisms. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2023; 88:367-380. [PMID: 37522439 PMCID: wst_2023_224 DOI: 10.2166/wst.2023.224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
The high water content of waste-activated sludge restricts the subsequent disposal of sludge. The dehydration properties of O3, ferric chloride (FeCl3)/polyacrylamide, and sludge ceramsite sand (SCS) were studied. Simultaneously, the effect of combining the three was investigated to support the deep dehydration of waste-activated sludge. Experimental results showed that with13.42 mg/(g dry solids (DS)) of O3, 109.89 mg/(g DS) of FeCl3, and 100 mesh dosage of 70% DS of sludge ceramsite on weight, the highest sludge net yield was 7.13 kg/(m2·h) and the minimum specific resistance to filtration of sludge cake was 1.02 × 1012 (m/kg). Compared with the compressibility of the raw sludge, the compressibility of the sludge cake decreased by 37.48%. Moreover, the YN (net yield) increased by 73.55%. The results demonstrate that the structure of cracking, flocculation, and hydrophobic framework is the mechanism of sludge dewatering in this combined process. This combined treatment process provides a new perspective for the realization of deep dewatering of sludge and is anticipated to be a successful sludge dehydration method.
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Affiliation(s)
- Ting Xia
- College of Urban Construction, Nanjing Tech University, Puzhu Road 30, Nanjing 211816, China E-mail:
| | - Xu Zhang
- College of Urban Construction, Nanjing Tech University, Puzhu Road 30, Nanjing 211816, China
| | - Dongjie Chen
- College of Urban Construction, Nanjing Tech University, Puzhu Road 30, Nanjing 211816, China
| | - Zaizhuang Gao
- College of Urban Construction, Nanjing Tech University, Puzhu Road 30, Nanjing 211816, China
| | - Yuxiao Ji
- College of Urban Construction, Nanjing Tech University, Puzhu Road 30, Nanjing 211816, China
| | - Jianjun Xia
- College of Urban Construction, Nanjing Tech University, Puzhu Road 30, Nanjing 211816, China
| | - Lei Wang
- Anhui Academy of Environmental Science Research, Hefei 230071, China
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Zhu H, Yang Z, Yao Y, Ju X, Wang D, Liu Y, Zhang Y, Zhou A. Preparation of the modified sludge-semi-coke water slurry and analysis of its slurring performance and mechanism. POWDER TECHNOL 2023. [DOI: 10.1016/j.powtec.2022.118039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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