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Zhang J, Zhang Y, Lv N, Li F, Li Y, Guo Z. Electrochemistry promotion of Fe(Ⅲ)/Fe(Ⅱ) cycle for continuous activation of PAA for sludge disintegration: Performance and mechanism. ENVIRONMENTAL RESEARCH 2024; 256:119268. [PMID: 38815721 DOI: 10.1016/j.envres.2024.119268] [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: 03/20/2024] [Revised: 05/13/2024] [Accepted: 05/27/2024] [Indexed: 06/01/2024]
Abstract
In this study, electrochemistry was used to enhance the advanced oxidation of Fe(Ⅱ)/PAA (EC/Fe(Ⅱ)/PAA) to disintegrate waste activated sludge, and its performance and mechanism was compared with those of EC, PAA, EC/PAA and Fe(Ⅱ)/PAA. Results showed that the EC/Fe(Ⅱ)/PAA process effectively improved sludge disintegration and the concentrations of soluble chemical oxygen demand, polysaccharides and nucleic acids increased by 62.85%, 41.15% and 12.21%, respectively, compared to the Fe(Ⅱ)/PAA process. Mechanism analysis showed that the main active species produced in the EC/Fe(Ⅱ)/PAA process were •OH, R-O• and FeIVO2+. During the reaction process, sludge flocs were disrupted and particle size was reduced by the combined effects of active species oxidation, electrochemical oxidation and PAA oxidation. Furthermore, extracellular polymeric substances (EPS) was degraded, the conversion of TB-EPS to LB-EPS and S-EPS was promoted and the total protein and polysaccharide contents of EPS were increased. After sludge cells were disrupted, intracellular substances were released, causing an increase in nucleic acids, humic acids and fulvic acids in the supernatant, and resulting in sludge reduction. EC effectively accelerated the conversion of Fe(Ⅲ) to Fe(Ⅱ), which was conducive to the activation of PAA, while also enhancing the disintegration of EPS and sludge cells. This study provided an effective approach for the release of organic matter, offering significant benefits in sludge resource utilization.
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Affiliation(s)
- Jing Zhang
- School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin, 300401, China
| | - Yanping Zhang
- School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin, 300401, China.
| | - Ning Lv
- School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin, 300401, China
| | - Fen Li
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology, Harbin, 150040, Heilongjiang, China
| | - Yibing Li
- School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin, 300401, China
| | - Zhenjie Guo
- School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin, 300401, China
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Lin X, Hu J, Mo Z, Wang Z, Wang R, Liang J. pH-dependent mechanisms of sulfadiazine degradation by natural pyrite-driven heterogeneous Fenton-like reactions. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 365:121607. [PMID: 38941847 DOI: 10.1016/j.jenvman.2024.121607] [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: 02/14/2024] [Revised: 06/08/2024] [Accepted: 06/23/2024] [Indexed: 06/30/2024]
Abstract
The development of a natural pyrite/peroxymonosulfate (PMS) system for the removal of antibiotic contamination from water represented an economic and green sustainable strategy. Yet, a noteworthy knowledge gap remained considering the underlying reaction mechanism of the system, particularly in relation to its pH sensitivity. Herein, this paper investigated the impacts of critical reaction parameters and initial pH levels on the degradation of sulfadiazine (SDZ, 3 mg/L) in the pyrite/PMS system, and elucidated the pH dependence of the reaction mechanism. Results showed that under optimal conditions, SDZ could be completely degraded within 5 min at a broad pH range of 3.0-9.0, with a pseudo-first-order reaction rate of >1.0 min-1. The low or high PMS doses could lower degradation rates of SDZ through the decreased levels of active species, while the amount of pyrite was positively correlated with the removal rate of SDZ. The diminutive concentrations of anions exerted minor impacts on the decomposition of SDZ within the pyrite PMS system. Mechanistic results demonstrated that the augmentation of pH levels facilitated the transition from the non-radical to the radical pathway within the natural pyrite/PMS system, while concurrently amplifying the role of •OH in the degradation process of SDZ. This could be attributed to the change in interface electrostatic repulsion induced by pH fluctuations, as well as the mutual transformation between active species. The stable presence of the relative content of Fe(II) in the used pyrite was ensured owing to the reduced sulfur species acting as electron donors, providing the pyrite/PMS system excellent reusability. This paper sheds light on the mechanism regulation of efficient removal of organic pollutants through pyrite PMS systems, contributing to practical application.
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Affiliation(s)
- Xiaoxuan Lin
- Guangdong Food and Drug Vocational College, Guangzhou, 510520, China; College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - Jinwen Hu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zhihua Mo
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, China
| | - Zhen Wang
- Guangdong Food and Drug Vocational College, Guangzhou, 510520, China
| | - Ruyi Wang
- Guangdong Food and Drug Vocational College, Guangzhou, 510520, China
| | - Jialin Liang
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China.
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3
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Luo F, Liu Z, Wang S, Wang J, He L, Liao Z, Hou H, Liu X, Wang X, Chen Z. Deep dewatering of sludge and resource recovery of hydroxyapatite: A recyclable approach via ionic liquid biphasic system and hydrogen bonds reformation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 934:173095. [PMID: 38729370 DOI: 10.1016/j.scitotenv.2024.173095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/06/2024] [Accepted: 05/07/2024] [Indexed: 05/12/2024]
Abstract
Deep dewatering of Waste Activated Sludge (WAS) through mechanical processes remains inefficient, primarily due to the formation of a stable hydrogen bonding network between the biopolymers and water, which consequently leads to significant water trapped by Extracellular Polymeric Substances (EPS). In this study, a novel and recyclable treatment for WAS based on Ionic Liquids (ILs) was established, named IL-biphasic aqueous system (IL-ABS) treatment. Specifically, the IL-ABS formed in WAS facilitated rapid and efficient in-situ deep dewatering while concurrently recovering hydroxyapatite. The water content decreased from an initial 98.27 % to 65.35 % with IL-ABS, formed by 1-Butyl-3-methylimidazolium bromide (BmimBr) and K3PO4 synthesized from waste H3PO4. Moreover, the recycled BmimBr maintaining the water content of the dewatered sludge consistently between 65.61 % and 67.25 % across five cycles, exhibited remarkable reproducibility. Through three-dimensional excitation-emission matrix, lactate dehydrogenase analyses and confocal laser scanning microscopy, the high concentration of BmimBr in the upper phase effectively disrupted the cells and EPS, which exposed protein and polysaccharide on the EPS surface. Subsequently, the K3PO4 in the lower phase led to an enhanced salting-out effect in WAS. Furthermore, FT-IR analysis revealed that K3PO4 disrupted the original hydrogen bonds between EPS and water. Then, BmimBr formed numerous hydrogen bonds with the sludge flocs, leading to deep dewatering and agglomeration of the sludge flocs during the unique phase separation process of IL-ABS. Notably, sludge-derived hydroxyapatite product exhibited remarkable adsorption capacity for prevalent heavy metal contaminants such as Pb2+, Cd2+ and Cu2+, with efficiencies comparable to those of commercial hydroxyapatite, thereby achieving the resource utilization of waste H3PO4. Moreover, economic calculations demonstrated the suitability of this novel treatment. This innovative treatment exhibits potential for practical applications in the non-mechanical deep dewatering of WAS.
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Affiliation(s)
- Fang Luo
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Zhuo Liu
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Siqi Wang
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Jia Wang
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Lingzhi He
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Zhuwei Liao
- Urban Construction Engineering Division, Wenhua College, Wuhan, China
| | - Huijie Hou
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Xiangrui Liu
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Xinxin Wang
- Urban Construction Engineering Division, Wenhua College, Wuhan, China
| | - Zhuqi Chen
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China.
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4
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Li C, Zhang Y, Ren J, Mo Z, Liang J, Ye M, Ou W, Sun S, Zhu S. In-situ generation of iron activated percarbonate for sustainable sludge dewatering. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 922:171235. [PMID: 38417502 DOI: 10.1016/j.scitotenv.2024.171235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 02/12/2024] [Accepted: 02/22/2024] [Indexed: 03/01/2024]
Abstract
Effective dewatering of sewage sludge could potentially address the issues of high energy consumption and large carbon footprint inherent in the sludge treatment process, advancing toward carbon neutrality in environmental remediation. Yet, the surface hydrophilic characteristics and water-holding interfacial affinity in sludge led to dwindled sludge-water separation performance. Here, the integration of in-situ generation of iron from zero-valent scrap iron (ZVSI) and sodium percarbonate (SPC) was attempted to attenuate the water-retaining interfacial affinity within sludge, thus achieving superior sludge dewatering performance. Results showed that under the optimal conditions, the ZVSI + SPC system led to a remarkable decline of 76.09 % in the specific resistance to filtration of the sludge, accompanied by a notable decline of 34.96 % in the water content. Moreover, the utilization of ZVSI + SPC system could be a viable alternative to the traditional strategies in terms of enhanced sludge dewaterability, offering application potential with stable operating performance, economic feasibility, and reduced carbon emissions. Investigation into dewatering mechanism revealed that ZVSI could maintain the Fe3+/Fe2+ in a stable dynamic cycle and continuously in-situ generate Fe2+, thereby efficaciously fostering the SPC activation for the ceaseless yield of reactive oxygen species. The predominant •OH and 1O2 efficiently decomposed the hydrophilic biopolymers, therefore minimizing the hydrophilic protein secondary structures, along with the hydrogen and disulfide bonds within proteins. Subsequently, the water-holding interfacial affinity was profoundly diminished, leading to intensified hydrophobicity, self-flocculation, and dewaterability. These findings have important implications for the advancement of efficacious ZVSI + SPC conditioning techniques toward sustainable energy and low-carbon prospects.
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Affiliation(s)
- Chengjian Li
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Yu Zhang
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Jingsai Ren
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Zhihua Mo
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Jialin Liang
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
| | - Maoyou Ye
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Wenzhi Ou
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Shuiyu Sun
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Suiyi Zhu
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
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Xu S, Shi J, Deng J, Sun H, Wu J, Ye Z. Flocculation and dewatering of the Kaolin slurry treated by single- and dual-polymer flocculants. CHEMOSPHERE 2023; 328:138445. [PMID: 36963584 DOI: 10.1016/j.chemosphere.2023.138445] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 02/20/2023] [Accepted: 03/17/2023] [Indexed: 06/18/2023]
Abstract
To mitigate the sudden increase in the production of waste engineering slurry, predominantly composed of Kaolinite, this study investigated the flocculation and dewatering of Kaolin slurry treated with single- and dual-polymer flocculants. The influence of the flocculant type and dosage, under single- and dual-dose conditions, on slurry's sedimentation and the filtration characteristics, were thoroughly discussed. The results reveal that the adsorption bridging of the polymeric flocculant, resulting from hydrogen bonds, exerts a more significant effect than electrical neutralization on forming a large floc. Under single-dose conditions, nonionic polyacrylamides (NPAMs) with the strongest adsorption bridging leads to biggest flocs and the maximum settling rate of 21.55 mm/s. Under the dual-dose conditions of polymeric aluminium chloride (PAC) and PAM, the size of the slurry's floc decreases with an increase in PAC dosage. Nevertheless, the filtration performance of the slurry improves, with the lowest SRF value of the flocculated slurry being 1.58 × 1011 m/kg as 3‰ PAC and 3‰ NPAM is dosed. The improvement is explained by the micro-pore distribution of sludge. According to Mercury intrusion porosimetry (MIP) test, the slurry treated with the optimal dosage of dual-polymer flocculant exhibits the greatest sludge pore size and connected porosity (with a maximum value of 20.99%). Furthermore, the study discusses and compares the flocculation mechanism of single- and dual-polymer flocculants. The obtained results provide guidance for selecting appropriate flocculants for dewatering inorganic slurries, using different dewatering methods, such as gravitational thickening or filter pressing.
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Affiliation(s)
- Shanlin Xu
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China.
| | - Junqiang Shi
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China.
| | - Jing Deng
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China.
| | - Honglei Sun
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China.
| | - Jiawei Wu
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China.
| | - Zhaohui Ye
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China.
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6
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Patil Y, Sonawane SH, Shyam P, Sun X, Manickam S. Hybrid hydrodynamic cavitation (HC) technique for the treatment and disinfection of lake water. ULTRASONICS SONOCHEMISTRY 2023; 97:106454. [PMID: 37271031 DOI: 10.1016/j.ultsonch.2023.106454] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/18/2023] [Accepted: 05/22/2023] [Indexed: 06/06/2023]
Abstract
Water reclamation from lakes needs to be accomplished efficiently and affordably to ensure the availability of clean, disinfected water for society. Previous treatment techniques, such as coagulation, adsorption, photolysis, ultraviolet light, and ozonation, are not economically feasible on a large scale. This study investigated the effectiveness of standalone HC and hybrid HC + H2O2 treatment techniques for treating lake water. The effect of pH (3 to 9), inlet pressure (4 to 6 bar), and H2O2 loading (1 to 5 g/L) were examined. At pH = 3, inlet pressure of 5 bar and H2O2 loadings of 3 g/L, maximum COD and BOD removal were achieved·H2O2 was observed to significantly improve the performance of the HC when used as a chemical oxidant. In an optimal operating condition, a COD removal of 54.5 % and a BOD removal of 51.5 % using HC alone for 1 h is observed. HC combined with H2O2 removed 64 % of both COD and BOD. The hybrid HC + H2O2 treatment technique resulted in a nearly 100% removal of pathogens. The results of this study indicate that the HC-based technique is an effective method for removing contaminants and disinfection of the lake water.
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Affiliation(s)
- Yogesh Patil
- Department of Chemical Engineering, National Institute of Technology Warangal, Telangana 506004, India
| | - Shirish H Sonawane
- Department of Chemical Engineering, National Institute of Technology Warangal, Telangana 506004, India.
| | - Perugu Shyam
- Department of Biotechnology, National Institute of Technology Warangal, Telangana 506004, India
| | - Xun Sun
- Key Laboratory of High Efficiency and Clean Mechanical Manufacture of Ministry of Education, School of Mechanical Engineering, Shandong University, Jinan 250061, China.
| | - Sivakumar Manickam
- Petroleum and Chemical Engineering, Faculty of Engineering, Universiti Teknologi Brunei, Bandar Seri Begawan BE1410, Brunei Darussalam
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Pan W, Li J, Zhang X, Liang S, Kang Y, Deng R, Gu L, He Q. Effect of KMnO 4/pH adjustment of extracellular polymeric substances under waste activated sludge on sludge dewatering. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:67326-67337. [PMID: 37106308 DOI: 10.1007/s11356-023-27171-2] [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: 12/05/2022] [Accepted: 04/18/2023] [Indexed: 05/25/2023]
Abstract
In this study, we examine the dewaterability of sludge after treatment by KMnO4 at various pH levels, with the goal of understanding the dewaterability of strong oxidizers to waste activated sludge. Good dewatering performance is observed, with capillary suction times (CST) reduced from 263.4 to 30.1 s, and specific resistance to filtration (SRF) falling by 19.6%. Proteins and polysaccharides in tightly bound extracellular polymeric substances (EPS) were also significantly reduced. Based on spectroscopic and electrochemical analysis, we propose mechanisms for the improved dewatering in terms of changes to the sludge's physicochemical properties and EPS. Under strong oxidation, the structure surrounding the bound water is oxidized and bound water is released, so the dewaterability of the sludge is improved.Weiliang Pan and Jiaoni Li contributed equally to this work.
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Affiliation(s)
- Weiliang Pan
- School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China.
| | - Jiaoni Li
- School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China
| | - Xun Zhang
- School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China
| | - Shan Liang
- School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China
| | - Yinghao Kang
- School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China
| | - Rui Deng
- School of Architecture and Urban Planning, Chongqing Jiaotong University, Chongqing, 400074, China
| | - Li Gu
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments, Ministry of Education, Institute of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Qiang He
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments, Ministry of Education, Institute of Environment and Ecology, Chongqing University, Chongqing, 400045, China
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8
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Zhu L, Tao H, Dai X, Dong B, Zhang W. Impact of hydrophilic functional groups of macromolecular organic fractions on food waste digestate dewaterability. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 326:116722. [PMID: 36372037 DOI: 10.1016/j.jenvman.2022.116722] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/22/2022] [Accepted: 11/04/2022] [Indexed: 06/16/2023]
Abstract
:Deterioration of dewaterability is one of challenges faced by anaerobic digestion (AD) of food waste (FW). The underlying mechanism of the effect of AD on digestate dewaterability remains unclear. Thus, the effect of hydrophilic functional groups of macromolecular organic on FW digestate dewaterability in different stages during AD was studied. Results showed that the dewaterability first improved at the acidification stage, and then worsened at the gasification and stabilization stages. The correlations between normalized capillary suction time (NCST), bound moisture (BM) and extracellular protein (extra-PN) were significant (R = 0.736, p < 0.05, R = 0.637, p < 0.05). Macromolecular extra-PN that enhance the bonding between organic fractions and moisture via peptide bonds. In addition, carbonyl, phenolic and amide groups increased after AD, resulting in the enhancement of the digestate hydrophilicity. Furthermore, the evolution of microbial community during AD resulting in the wrapping of BM by increased organic fractions. Therefore, higher organic fractions with hydrophilic functional groups in digestate strongly hinder moisture removal. The findings obtained deepen our understanding of hydrophilic functional groups of macromolecular organic affecting FW digestate dewaterability and provide strong supports to treatment and disposal of FW digestate.
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Affiliation(s)
- Li Zhu
- School of Environment and Architecture. University of Shanghai for Science and Technology, Shanghai, 200093, PR China
| | - Hong Tao
- School of Environment and Architecture. University of Shanghai for Science and Technology, Shanghai, 200093, PR China
| | - Xiaohu Dai
- School of Environmental Science and Engineering. Tongji University, Shanghai, 200092, PR China
| | - Bin Dong
- School of Environmental Science and Engineering. Tongji University, Shanghai, 200092, PR China
| | - Wei Zhang
- School of Environment and Architecture. University of Shanghai for Science and Technology, Shanghai, 200093, PR China.
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9
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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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10
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Ling X, Cai A, Chen M, Sun H, Xu S, Huang Z, Li X, Deng J. A comparison of oxidation and re-flocculation behaviors of Fe 2+/PAA and Fe 2+/H 2O 2 treatments for enhancing sludge dewatering: A mechanism study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 847:157690. [PMID: 35905956 DOI: 10.1016/j.scitotenv.2022.157690] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/24/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
In this study, Fe2+ activated-PAA was developed as a novel technology to enhance sludge dewatering. The result showed that the filterability (CST0/CST) enhanced by 4.20 ± 0.14 times more than the control, and the SRF and bound water content decreased from 4.58 ± 0.07 × 1013 m/kg and 2.11 ± 0.28 g/g dry sludge to 9.47 ± 0.05 × 1012 m/kg and 1.27 ± 0.18 g/g dry sludge, respectively after the sludge was conditioned by 1.20 mM/g VSS Fe2+ and 1.20 mM/g VSS PAA. The dewatering performance, physicochemical properties, aggregation behaviors, and EPS fractions of sludge were compared before and after Fe2+/PAA and Fe2+/H2O2 conditionings. The results showed that Fe2+/PAA treatment was more competitive in enhancing dewaterability under neutral and alkaline conditions than Fe2+/H2O2 treatment but slightly weaker under acid conditions. Besides, it was found that the oxidation and re-flocculation behaviors were different in those two enhanced dewatering technologies due to the difference in the generated ROS. R-O was the primary radical in the Fe2+/PAA system, while OH was the major one in the Fe2+/H2O2 system. The mechanism analysis found that the Fe2+/PAA process caused harsher disintegration of sludge flocs, meaning more generation of fine particles. However, it exhibited less effect on reducing the energy barrier between sludge particles. Therefore, the Fe2+/PAA treated sludge presented weaker aggregation behaviors. The weaker aggregation was unfavorable for sludge dewatering because the weaker aggregated flocs were more easily fragmented, which hampered the consolidation of sludge cakes and removal of bound water. Moreover, loosely-bound extracellular polymeric substances, particularly tightly-bound extracellular polymeric substances, governed the sludge dewaterability.
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Affiliation(s)
- Xiao Ling
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Anhong Cai
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Minjie Chen
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Honglei Sun
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Shanlin Xu
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Zhiyuan Huang
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Xueyan Li
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Jing Deng
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China.
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Ling X, Chen M, Cai A, Sun H, Xu S, Wang L, Li X, Deng J. A novel pre-magnetized ZVI/PS pretreatment for improving sludge dewaterability: The role of EPS fractions. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 318:115646. [PMID: 35949095 DOI: 10.1016/j.jenvman.2022.115646] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/26/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
The dewaterability of waste-activated sludge (WAS) has been extensively examined using zero-valent iron (ZVI)-based advanced oxidation processes (AOPs). However, the high dosage and low utilization efficiencies of ZVI cast doubt on the dependability and viability of ZVI-based AOPs. In this study, we successfully demonstrated pre-magnetization as an efficient, chemical-free, and ecological method for improving the efficiency of sludge dewatering by ZVI/persulfate (PS) process, in which the reduction ratios of capillary suction time (CST) and specific resistance to filtration (SRF) increased by 8.67% and 11.06% under optimal conditions, respectively. The highly active Fe2+ released during ZVI corrosion may be more essential than ZVI itself during PS activation, which could be strengthened by pre-magnetization. Both homogeneous and heterogeneous Fe2+ could react with PS to produce aqueous hydroxyl radicals (∙OH) and sulfate radicals (SO4-∙) as well as surface-bound ∙OH and SO4-∙, further decomposing bound-extracellular polymeric substances fractions, broking hydrophilic functional groups and compounds, altering protein secondary structure to expose more hydrophobic sites, and releasing abundant EPS-bound water. Due to the protection of tightly-bound extracellular polymeric substances (TB-EPS) and the competitive oxidation of organics released during the early disintegration stage, radical oxidation primarily occurs at extracellular levels, releasing a bit of intracellular water. Besides, polysaccharides in TB-EPS may function a more significant role in flocculation than proteins, and a porous structure favorable to drainage will be formed after the pre-magnetized ZVI/PS treatment. The cost-benefit analysis further reveals that the Pre-ZVI/PS process presents high reusability and utilization, making it potential for particle application in sludge dewatering.
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Affiliation(s)
- Xiao Ling
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Minjie Chen
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Anhong Cai
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Honglei Sun
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Shanlin Xu
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Lei Wang
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Xueyan Li
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Jing Deng
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China.
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Li B, Han Z, Ma J, Qiu W, Li W, Zhang B, Zhai X, Ding A, He X. Novel sodium percarbonate-MnO 2 effervescent tablets for efficient and moderate membrane cleaning. WATER RESEARCH 2022; 220:118716. [PMID: 35687974 DOI: 10.1016/j.watres.2022.118716] [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: 03/27/2022] [Revised: 05/24/2022] [Accepted: 06/04/2022] [Indexed: 06/15/2023]
Abstract
Membrane flux recovery efficiency and durability are two key factors closely associated with the practical application for membrane cleaning process. However, conventional chemical membrane cleaning method by soaking the whole membrane module in highly concentrated chemical reagents has prominent drawbacks including the low mass transfer efficiency of reagents, long period of washing time, and the potential threat to membrane structure. Herein, for the first time, we report a facile approach to fabricate the sodium percarbonate-MnO2 effervescent tablets which show bubbling reaction to release oxygen and free radicals when being dispersed in water for membrane cleaning. Due to the synergistic effect of MnO2 and sodium percarbonate, the tablets are highly effective to clean the membrane fouled by humic acid within 5 min, with the terminal membrane flux being recovered from 0.50 to 0.95, and the irreversible fouling resistance being reduced by more than 90%, which is prominently more efficient than the conventional chemical cleaning methods. Moreover, even by consecutive membrane fouling and cleaning for 6 times, the membrane flux and filtration efficiency of the membrane could still be kept almost constant, and the moderateness of this membrane cleaning method was also verified by the systematic microscopic analysis. For mechanism study, results of Electron Spin Resonance (ESR) and quenching experiments indicated that the high-efficiency and robust durability of sodium percarbonate-MnO2 (SPC-MnO2) system for membrane cleaning was mainly attributed to the abundantly generated hydroxyl radicals and secondary free radicals (i.e. carbonate radicals). Conclusively, compared with the conventional membrane cleaning method with liquid cleaning reagents, the novel SPC-MnO2 system with remarkable advantages in terms of convenience and membrane cleaning performance demonstrated high potential for the wide application in practice.
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Affiliation(s)
- Boda Li
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Ziwen Han
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Wei Qiu
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Wenqian Li
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Bin Zhang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Xuedong Zhai
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - An Ding
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Xu He
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, 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: 2] [Impact Index Per Article: 1.0] [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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