1
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Wang X, Lu Y, Yan Y, Wang R, Wang Y, Li H, Zhou L, Zheng G, Zhang Y. Pivotal role of intracellular oxidation by HOCl in simultaneously removing antibiotic resistance genes and enhancing dewaterability during conditioning of sewage sludge using Fe 2+/Ca(ClO) 2. Water Res 2024; 254:121414. [PMID: 38461604 DOI: 10.1016/j.watres.2024.121414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 02/25/2024] [Accepted: 03/03/2024] [Indexed: 03/12/2024]
Abstract
Pre-acidification has been shown to be crucial in attenuating antibiotic resistance genes (ARGs) during the conditioning of sewage sludge. However, it is of great significance to develop alternative conditioning approaches that can effectively eliminate sludge-borne ARGs without relying on pre-acidification. This is due to the high investment costs and operational complexities associated with sludge pre-acidification. In this study, the effects of Fe2+/Ca(ClO)2 conditioning treatment on the enhancement of sludge dewaterability and the removal of ARGs were compared with other conditioning technologies. The dose effect and the associated mechanisms were also investigated. The findings revealed that Fe2+/Ca(ClO)2 conditioning treatment had the highest potential, even surpassing Fenton treatment with pre-acidification, in terms of eliminating the total ARGs. Moreover, the effectiveness of the treatment was found to be dose-dependent. This study also identified that the •OH radical reacted with extracellular polymeric substance (EPS) and extracellular ARGs, and the HOCl, the production of which was positively correlated with the dose of Fe2+/Ca(ClO)2, could infiltrate the EPS layer and diffuse into the cell of sludge flocs, inducing the oxidation of intracellular ARGs. Furthermore, this study observed a significant decrease in the predicted hosts of ARGs and MGEs in sludge conditioned with Fe2+/Ca(ClO)2, accompanied by a significant downregulation of metabolic pathways associated with ARG propagation, thereby contributing to the attenuation of sludge-borne ARGs. Based on these findings, it can be concluded that Fe2+/Ca(ClO)2 conditioning treatment holds great potential for the removal of sludge-borne ARGs while also enhancing sludge dewaterability, which mainly relies on the intracellular oxidation by HOCl.
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Affiliation(s)
- Xinxin Wang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yu Lu
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yiwen Yan
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Ru Wang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuhang Wang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Hua Li
- Department of Civil Engineering, College of Urban Construction, Nanjing Tech University, Nanjing 211816, 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
| | - 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.
| | - Yifeng Zhang
- Department of Environmental and Resource Engineering, Technical University of Denmark, Lyngby DK-2800, Denmark
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2
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Chen C, Zhang T, Lv L, Tang W, Tang S. Hybrid conditioning of ionic liquid coupling with H 2SO 4 to improve the dewatering performance of municipal sludge. Environ Sci Pollut Res Int 2024; 31:29513-29524. [PMID: 38578595 DOI: 10.1007/s11356-024-33135-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 03/25/2024] [Indexed: 04/06/2024]
Abstract
Municipal sludge generated from wastewater treatment plants can cause a serious environmental and economic burden. A novel hybrid conditioning strategy was developed to enhance the dewatering performance of sludge, employing 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([C4mim][CF3SO3]) treatment combined with H2SO4 acidification. Following conditioning, the capillary suction time ( CST normalized ), the specific resistance of filtration (SRF), and moisture content of the treated sludge were decreased to 1.99 ± 0.24 (s·L/g TSS), 1.33 ± 0.05 (1012 m/kg), and 72.01 ± 0.94%, respectively. The results were superior to those achieved with sludge treated solely by H2SO4 acidification or [C4mim][CF3SO3] alone. The biomacromolecules within the sludge flocs were dissolved by [C4mim][CF3SO3], while simultaneously, the microorganisms were inactivated. Consequently, the colloidal-like structures of the sludge flocs were destroyed. Additionally, the ionizable functional groups of the biomacromolecules were instantly protonated by the introduced H+ ions, and their negative charges were neutralized during the H2SO4 acidification process. The presence of H+ ions promoted the weakening of electrostatic repulsion between the sludge flocs. As a result, an enhancement of sludge dewaterability was obtained after treatment with [C4mim][CF3SO3] and H2SO4 acidification. The finding of the intensification mechanism of sludge dewaterability brought by hybrid treatment of acidification and [C4mim][CF3SO3] provides novel insights into the field of sludge disposal.
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Affiliation(s)
- Changtao Chen
- Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, 610065, China
- LIWET, Laboratory for Industrial Water and EcoTechnology, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Campus Kortrijk, Sint-Martens-Latemlaan 2B, B-8500, Kortrijk, Belgium
| | - Tao Zhang
- Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, 610065, China
| | - Li Lv
- Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, 610065, China
| | - Wenxiang Tang
- Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, 610065, China
| | - Shengwei Tang
- Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu, 610065, China.
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3
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Liu Z, Heng S, Dai Q, Gao Y, Han Y, Hu L, Liu Y, Lu X, Zhen G. Simultaneous removal of antibiotic resistance genes and improved dewatering ability of waste activated sludge by Fe(II)-activated persulfate oxidation. Water Res 2024; 253:121265. [PMID: 38340701 DOI: 10.1016/j.watres.2024.121265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/21/2024] [Accepted: 02/04/2024] [Indexed: 02/12/2024]
Abstract
Waste activated sludge properties vary widely with different regions due to the difference in living standards and geographical distribution, making a big challenge to developing a universally effective sludge dewatering technique. The Fe(II)-activated persulfate (S2O82-) oxidation process shows excellent ability to disrupt sludge cells and extracellular polymeric substances (EPS), and release bound water from sludge flocs. In this study, the discrepancies in the physicochemical characteristics of sludge samples from seven representative cities in China (e.g., dewaterability, EPS composition, surface charge, microbial community, relative abundance of antibiotic resistance genes (ARGs), etc.) were investigated, and the role of Fe(II)-S2O82- oxidation in enhancing removal of antibiotic resistance genes and dewatering ability were explored. The results showed significant differences between the EPS distribution and chemical composition of sludge samples due to different treatment processes, effluent sources, and regions. The Fe(II)-S2O82- oxidation pretreatment had a good enhancement of sludge dewatering capacity (up to 76 %). Microbial analysis showed that the microbial community in each sludge varied significantly depending on the types of wastewater, the wastewater treatment processes, and the regions, but Fe(II)-S2O82- oxidation was able to attack and rupture the sludge zoogloea indiscriminately. Genetic analysis further showed that a considerable number of ARGs were detected in all of these sludge samples and that Fe(II)-S2O82- oxidation was effective in removing ARGs by higher than 90 %. The highly active radicals (e.g., SO4-·, ·OH) produced in this process caused drastic damage to sludge microbial cells and DNA stability while liberating the EPS/cell-bound water. Co-occurrence network analysis highlighted a positive correlation between population distribution and ARGs abundance, while variations in microbial communities were linked to regional differences in living standards and level of economic development. Despite these variations, the Fe(II)-S2O82- oxidation consistently achieved excellent performance in both ARGs removal and sludge dewatering. The significant modularity of associations between different microbial communities also confirms its ability to reduce horizontal gene transfer (HGT) by scavenging microbes.
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Affiliation(s)
- Zhaobin Liu
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Shiliang Heng
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Qicai Dai
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Yijing Gao
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Yule Han
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Lingtian Hu
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Yisheng Liu
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Xueqin Lu
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, Shanghai 200241, PR China; Institute of Eco-Chongming (IEC), 3663N. Zhongshan Rd., Shanghai 200062, China
| | - Guangyin Zhen
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, Shanghai 200241, PR China; Shanghai Institute of Pollution Control and Ecological Security, 1515 North Zhongshan Rd. (No. 2), Shanghai 200092, PR China; Technology Innovation Center for Land Spatial Eco-restoration in Metropolitan Area, Ministry of Natural Resources, 3663N. Zhongshan Road, Shanghai 200062, China.
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4
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Li Y, Quan L, Li J, Zhang Z, Lv J, Fu C, Chen Z. The role of microstructure of extracellular proteins in dewaterability of alkaline pretreatment sludge during bioleaching. Environ Res 2024; 244:117969. [PMID: 38109956 DOI: 10.1016/j.envres.2023.117969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 12/09/2023] [Accepted: 12/15/2023] [Indexed: 12/20/2023]
Abstract
Alkaline pre-treatment is known to enhance the acid production efficiency of sludge but adversely affects its dewatering performance. In this study, the improvement of sludge dewaterability by a novel bioleaching system with inoculating domesticated acidified sludge (AS) and its underlying mechanism were investigated. The results showed that although the addition of Fe2+ and the reduction of pH improved the dewatering performance of sludge, their effects were inferior to that of AS + Fe. The addition of AS and Fe2+ significantly reduced the specific resistance to filtration and capillary suction time of the sludge by 98.6 % and 95.5 %, respectively. This improvement in dewatering performance was achieved through the combined actions of bio-acidification, bio-oxidation, and bio-flocculation. Remarkably, under alkaline pH, microorganisms in AS remained active, leading to the formation of iron-based bioflocculants, along with a rapid pH decrease. These bioflocculants, in combination with protein (PN) in tightly bound extracellular polymeric substances (TB-EPS) through amide bonding, transformed TB-EPS from extractable to non-extractable form, reducing PN content from 12.1 mg g-1DS to 5.09 mg g-1DS and altering the protein's secondary structure. Consequently, the gel-like TB-EPS matrix effectively broke down, releasing cellular water and significantly enhancing sludge dewaterability.
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Affiliation(s)
- Yunbei Li
- School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang, 453007, China.
| | - Lijun Quan
- School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang, 453007, China
| | - Jingyu Li
- School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang, 453007, China
| | - Zhiwen Zhang
- School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang, 453007, China
| | - Jinghua Lv
- School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang, 453007, China
| | - Chunyan Fu
- School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang, 453007, China
| | - Zhiqiang Chen
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
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5
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Zhang W, Zhu L, Yang X, Zhu J, Dong B, Tao H. Targeted regulation of digestate dewaterability by the ozone/persulfate oxidation process. J Environ Manage 2024; 354:120332. [PMID: 38364539 DOI: 10.1016/j.jenvman.2024.120332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/14/2024] [Accepted: 02/08/2024] [Indexed: 02/18/2024]
Abstract
Dewatering is the first step in the subsequent treatment and disposal of food waste digestate (FWD). However, FWD is difficult to dewatering. In this study, persulfate was synergistic oxidized by ozone to improve digestate dewaterability. The optimal conditions was at pH = 3, O3=40 mg/g TS and PDS=0.1 g/g TS, under which the reductions in the normalized capillary suction time (NCST) and bound moisture (BM) of the FWD were 89.97% and 65.79%, respectively. Hydrophilic functional groups (oxygen- and nitrogen-containing groups) and hydrophilic protein molecular structures were decomposed by the reactive species of sulfate radical (SO4·-) and hydroxyl radicals (·OH) generated in the ozone-persulfate oxidation process, disrupting the binding between EPS and water molecules. The contributions of SO4·- and ·OH to digestate dewaterability were 42.51% and 28.55%. In addition, the introduction of H+ reduced electrostatic repulsion and contributed to the condensation of digestate flocs. The environmental implication assessment and economic analysis suggested that the O3/PDS oxidation process was cost-effective and has a low environmental implication when applied to the FWD dewaterability improvement process. These results can serve as a reference for the management of FWD and further improvement of FWD treatment and disposal efficiency.
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Affiliation(s)
- Wei Zhang
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, 200093, PR China.
| | - Li Zhu
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, 200093, PR China
| | - Xue Yang
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, 200093, PR China
| | - Jing Zhu
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, 200093, PR China
| | - Bin Dong
- School of Environmental Science and Engineering. Tongji University, Shanghai, 200092, PR China
| | - Hong Tao
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, 200093, PR China
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6
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Yuan H, Zhu N. Progress of improving waste activated sludge dewaterability: Influence factors, conditioning technologies and implications and perspectives. Sci Total Environ 2024; 912:168605. [PMID: 37989393 DOI: 10.1016/j.scitotenv.2023.168605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/06/2023] [Accepted: 11/14/2023] [Indexed: 11/23/2023]
Abstract
Large amounts of waste activated sludge (WAS) as a by-product generated from the biological treatment in wastewater treatment plants (WWTPs) is of high moisture content (MC), organic pollutants, heavy metals and pathogenic bacteria, it may cause serious environmental ecological risk without appropriate disposal. More than one half of the total operation cost is accounted for sludge disposal in a WWTP. Dewatering is an essential and important step during the sludge treatment and disposal process for it could efficiently reduce its volume, and be beneficial to the subsequent treatment and disposal of sludge. However, sludge should be conditioned before mechanical dewatering because of its high hydrophilicity. In this work, it presented a comprehensive review on sludge dewatering including summarizing the dewaterability measurement indexes, affecting factors, conditioning technologies, the improvement mechanisms. Finally, based on the eventual disposal and low carbon emission target, the implications and perspectives development of sludge conditioning were discussed. Based on the above discussion, there is no unified theoretical insight of the improvement mechanism of sludge dewaterability. In addition, the relationship between the microstructure of organic matters in sludge floc and the dewaterability should be deepened. Especially, how to choose the optimal conditioning technology for sludge dewatering lies in the physical and chemical properties of sludge, however, the carbon emission of the conditioning and dewatering process also needs to be considered. Accordingly, green, low-cost and organic conditioning agents are the direction of future research, and the establishment of automatic operating system and real-time evaluation index system is the key challenge.
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Affiliation(s)
- Haiping Yuan
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science and Engineering, Shanghai Jiao Tong University, No.800 Dongchuan Road, Shanghai 200240, China
| | - Nanwen Zhu
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science and Engineering, Shanghai Jiao Tong University, No.800 Dongchuan Road, Shanghai 200240, China.
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7
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Li W, Li L, Li B, Peng L, Xu Y, Li R, Song K. Effect and mechanism of perfluorooctanoic acid (PFOA) on anaerobic digestion sludge dewaterability. Chemosphere 2023:139142. [PMID: 37290510 DOI: 10.1016/j.chemosphere.2023.139142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/23/2023] [Accepted: 06/04/2023] [Indexed: 06/10/2023]
Abstract
Perfluorooctanoic acid (PFOA) as nonbiodegradable organic pollutant, its presence and risks in wastewater treatment system has aroused wide concern. This study investigated the effect and underlying mechanism of PFOA on anaerobic digestion sludge (ADS) dewaterability. Long-term exposure experiments were set up to investigate the effect with various concentration of PFOA dosed. Experimental results suggested that the existence of high concentration PFOA (over 1000 μg/L) could deteriorate ADS dewaterability. The long-term exposure to 100,000 μg/L PFOA of ADS increased specific resistance filtration (SRF) by 81.57%. It was found that PFOA promoted the release of extracellular polymeric substances (EPS), which was strongly associated with sludge dewaterability. The fluorescence analysis revealed that the high PFOA concentration could significantly improve the percentage of protein-like substances and soluble microbial by-product-like content, and then further deteriorated the dewaterability. The FTIR results showed that long-term exposure of PFOA caused loose protein structure in sludge EPS, which led to loose sludge floc structure. The loose sludge floc structure aggravated the deterioration of sludge dewaterability. The solids-water distribution coefficient (Kd) decreased with the increase of initial PFOA concentration. Moreover, PFOA significantly affected microbial community structure. Metabolic function prediction results showed significant decrease of fermentation function exposed to PFOA. This study revealed that the PFOA with high concentration could deteriorated sludge dewaterability, which should be highly concerned.
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Affiliation(s)
- Wenkai Li
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Lu Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, China
| | - Biqing Li
- Guangzhou Sewage Purification Co. Ltd., Guangzhou, 510655, China
| | - Lai Peng
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
| | - Yifeng Xu
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
| | - Renhui Li
- College of Life and Environmental Sciences, Wenzhou University, Zhejiang, 325035, China
| | - Kang Song
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, China.
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Xiao B, Chen X, Zhang K, Zheng T, Bian C, Liu J, Li L, Liu J. Improving sewage sludge dewaterability via heterogeneous activation of persulfate by Fe-Al layered double hydroxide: Role of generated SO 4-•. J Environ Manage 2023; 342:118194. [PMID: 37210818 DOI: 10.1016/j.jenvman.2023.118194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/07/2023] [Accepted: 05/15/2023] [Indexed: 05/23/2023]
Abstract
In this study, Fe-Al layered double hydroxide (Fe-Al LDH) was prepared and applied to activate persulfate to condition sewage sludge and improve its dewaterability. The results showed that Fe-Al LDH activated persulfate to generate a large amount of free radicals, which attacked extracellular polymeric substances and reduced their content, disrupted microbial cells, released bound water, decreased sludge particle size, increased sludge zeta potential, and improved sludge dewaterability. After sewage sludge was conditioned with Fe-Al LDH (0.20 g/g total solids (TS)) and persulfate (0.10 g/g TS) for 30 min, the capillary suction time of the sludge dropped from 52.0 s to 16.3 s, while the moisture content of the sludge cake decreased from 93.2% to 68.5%. The dominant active free radical produced by the Fe-Al LDH-activated persulfate was SO4-•. The maximum Fe3+ leaching of the conditioned sludge was only 102.67 ± 4.45 mg/L, thus effectively alleviating the secondary pollution of Fe3+. The leaching rate of 2.37% was significantly lower than that of the sludge homogeneously activated with Fe2+ (738.4 ± 26.07 mg/L and 71.00%).
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Affiliation(s)
- Benyi Xiao
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Science, Beijing 100049, China
| | - Xiangyu Chen
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Science, Beijing 100049, China
| | - Ke Zhang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Science, Beijing 100049, China
| | - Tianlong Zheng
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Science, Beijing 100049, China.
| | - Chunlin Bian
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Inner Mongolia University of Technology, Hohhot, Inner Mongolia, 010051, China
| | - Jianguo Liu
- Inner Mongolia University of Technology, Hohhot, Inner Mongolia, 010051, China.
| | - Lin Li
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Science, Beijing 100049, China
| | - Junxin Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Science, Beijing 100049, China
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9
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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. Environ Sci Pollut Res Int 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] [What about the content of this article? (0)] [Affiliation(s)] [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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10
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Chen C, Zhang T, Lv L, Chen Y, Tang W, Tang S. A novel insight on the intensification mechanism of sludge dewaterability by ionic liquids. J Environ Manage 2023; 331:117291. [PMID: 36657200 DOI: 10.1016/j.jenvman.2023.117291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 01/01/2023] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
The huge output of sewage sludge has caused a remarkable environmental burden. Sludge dewatering is considered as an important way to reduce the sludge volume. Five imidazole-based ionic liquids were used to improve the dewaterability of sewage sludge. 1-ethyl-3-methylimidazolium dihydrogen phosphate ([Emim][H2PO4]) was screened out as a potential conditioner of sludge due to its excellent dewatering performance and reusability. The solid content of sludge filter cake after treatment with [Emim][H2PO4] was about 10% higher than that of sludge treated by cationic polyacrylamides (CPAM). The intensification mechanism of ionic liquids to the improvement of sludge dewatering performance was studied. The presence of acidic ionic liquids [Emim][H2PO4] resulted the increase of zeta potential from -14.57 ± 0.81 mV to -5.60 ± 0.30 mV and led to the protonation of biopolymers. Acidic ionic liquids [Emim][H2PO4] inactivated the microorganism and led to a porous and unconsolidated structure of the solid sludge particles. All these effects were conducive to destroy the microstructure of sludge and release water. However, [Emim]Cl, [Bmim][OTf] and [Hmim][OTf] showed little effect on the protonation of ionizable functional groups at near-neutral environment. The dissolution of biopolymer decreased the zeta potential and strengthened the electrostatic repulsion. So, they showed weaker intensification effects than CPAM.
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Affiliation(s)
- Changtao Chen
- Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, Chengdu, 610065, China.
| | - Tao Zhang
- Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, Chengdu, 610065, China.
| | - Li Lv
- Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, Chengdu, 610065, China.
| | - Yanxiao Chen
- Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, Chengdu, 610065, China.
| | - Wenxiang Tang
- Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, Chengdu, 610065, China.
| | - Shengwei Tang
- Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, Chengdu, 610065, China.
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11
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Yuan D, Li X, Xiong S, Cui J, Zhou J, Kou Y. Improving sludge dewaterability via Fe 2+ chelated citrate activated peroxydisulfate oxidation. J Environ Sci (China) 2023; 125:223-233. [PMID: 36375908 DOI: 10.1016/j.jes.2021.11.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 06/16/2023]
Abstract
Citrate (Ct) was chosen as a typical chelator used in the Fe2+-peroxydisulfate (PDS) process to improve sludge dewaterability. The PDS-Fe2+-Ct process exhibited better performance in sludge dewatering than PDS-Fe2+. Specifically, with a PDS dosage of 1.2 mmol/g VS, the molar ratio of PDS/Fe2+ and Ct/Fe2+ were 4:5 and 1:4, respectively, the capillary suction time decreased from 155.8 to 24.8sec, and the sludge cake water content decreased from 82.62% to 64.11% (-0.06MPa). The oxidation led to a reduced negative charge and a decrease in particle size. The enhanced sludge dewaterability and changes of sludge properties were attributed to the decomposition of extracellular polymeric substances, and it was explored by protein, polysaccharide, 3D-EEMs, and FT-IR. Additionally, the quenching experiments of radical species demonstrated that SO4-• played a more important role than •OH, and its productivity was improved with the addition of Ct. Moreover, the reasons for the improved productivity of radicals with the addition of Ct were discussed. The results of this study could serve as a basis for improving sludge dewatering using the PDS-Fe2+-Ct process and suggest that the addition of Ct may improve the productivity of SO4-• in the activation of PDS via Fe2+.
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Affiliation(s)
- Donghai Yuan
- Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Xinyu Li
- Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Siyu Xiong
- Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Jun Cui
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jijiao Zhou
- Huzhou Environmental Sanitation Management Center, Huzhou 313000, China
| | - Yingying Kou
- Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China.
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12
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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. J Environ Manage 2023; 326:116722. [PMID: 36372037 DOI: 10.1016/j.jenvman.2022.116722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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13
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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. Sci Total Environ 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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Lu Q, Liu Q, Liu X, Li Y, Yin Z, Wang D. Enhanced dewaterability of anaerobically fermented sludge through acid-driven indigenous enzymatic hydrolysis. J Environ Manage 2022; 323:116212. [PMID: 36261978 DOI: 10.1016/j.jenvman.2022.116212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 08/05/2022] [Accepted: 09/05/2022] [Indexed: 06/16/2023]
Abstract
The poor dewaterability of fermented sludge is an important factor limiting the development of anaerobic fermentation applications. Herein we reported an efficient strategy, i.e., using acidic regulation to stimulate the release of indigenous enzymes, to enhance the hydrolysis and dewatering of fermented sludge. The results showed that after acidic regulation at pH 4.0 for 1 day, the activity of protease and α-glucosidase were improved by 131.4% and 146.0%, while the capillary suction time and specific resistance to filtration were decreased by 93.8% and 69.5%, respectively. Mechanism study revealed that the method firstly destroyed the slime and bound EPS and cells of fermented sludge, causing the release of indigenous enzymes (i.e., protease and α-glucosidase) contained in. Then, the released enzymes directly accelerated the hydrolysis and acidification of fragmentized extracellular polymeric substances, thereby benefited the release of bound water in sludge particles. Finally, such acidic condition decreased the electrostatic repulsive interactions between destroyed sludge particles, further improving their flocculation. The findings not only deepen the understanding of indigenous enzymes contained in fermented sludge affecting sludge dewatering, but also might guide engineers to develop promising strategies to facilitate fermented sludge dewatering and fermentation liquid recovery in the future.
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Affiliation(s)
- Qi Lu
- Department of Urology, Second Xiangya Hospital, Central South University, Changsha, 410011, PR China; College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha, 410082, PR China.
| | - Qiang Liu
- Department of Urology, Second Xiangya Hospital, Central South University, Changsha, 410011, PR China; College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha, 410082, PR China.
| | - Xuran Liu
- Department of Urology, Second Xiangya Hospital, Central South University, Changsha, 410011, PR China; College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha, 410082, PR China
| | - Yifu Li
- Department of Urology, Second Xiangya Hospital, Central South University, Changsha, 410011, PR China; College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha, 410082, PR China
| | - Zhuo Yin
- Department of Urology, Second Xiangya Hospital, Central South University, Changsha, 410011, PR China.
| | - Dongbo Wang
- Department of Urology, Second Xiangya Hospital, Central South University, Changsha, 410011, PR China; College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha, 410082, PR China.
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15
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Ding S, Sang X, Zhao Z, Ren H. Effects of potassium ferrate-walnut shell pretreatment on dehydration performance of residual sludge. Environ Sci Pollut Res Int 2022; 29:82439-82450. [PMID: 35752666 DOI: 10.1007/s11356-022-21646-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Sludge dehydration is not only the first process of sludge reduction but also difficult for sludge treatment and disposal, while the high moisture content of sludge would also limit its resource utilization. In this paper, the residual sludge was treated by the strong oxidizing property of potassium ferrate (PF), and walnut shells were used as a skeleton builder to obtain the recycling dehydrated sludge. It also provides a new solution for the poor stability of PF in the treatment of sludge and waste walnut shells. The experiment results showed that the optimum dosage of PF and walnut shell was 60 mg/gDS and 0.8 g/gDS, respectively, and the water content of the combined PF and walnut shell treatment decreased by 5.2% and 3.7% compared to that of PF conditioning alone and walnut shell conditioning alone, respectively. In addition, scanning electron microscopy and three-dimensional fluorescence spectroscopy revealed a large number of cracks on the sludge surface after the combined treatment, and the sludge floc structure became more loose and dispersed, and the hydrophobic substances humic acid and fulvic acid increased, indicating that the dewatering performance of the sludge was effectively improved, further confirming that the combined PF and walnut shells treatment provides a new idea and method for sludge dewatering.
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Affiliation(s)
- Shaolan Ding
- School of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an, 710021, People's Republic of China
| | - Xiangwei Sang
- School of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an, 710021, People's Republic of China.
| | - Zhen Zhao
- School of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an, 710021, People's Republic of China
| | - Huijun Ren
- School of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an, 710021, People's Republic of China
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16
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Jiang F, Feng X, Jiang X, Wang P. Enhanced dewaterability of lake dredged sediments by electrochemical oxidation of peroxydisulfate on BDD anode. Chemosphere 2022; 307:135832. [PMID: 35963373 DOI: 10.1016/j.chemosphere.2022.135832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Dredged sediments, as a product of mitigating endogenous pollution of rivers and lakes, cause severe environmental pollution without suitable disposal. To reduce dredged sediments, the electrochemical oxidation (EO) of peroxydisulfate (PS) on a boron-doped diamond (BDD) anode (EO/BDD-PS) was utilized to enhance the dewaterability of the dredged sediments. The soluble chemical oxygen demand increased in the EO/BDD-PS system, and more than 70.0% of the specific resistance to filtration was reduced by EO/BDD-PS within 20 min. The optimal conditions were determined to be as follows: current density, 30 mA cm-2; PS dosage 4 g L-1; and initial pH, 6.96. After treatment with EO/BDD-PS, the electronegativity of the sludge flocs was alleviated and the particle size increased from 7.61 to 10.64 μm. Furthermore, proteins and polysaccharides were degraded, and tightly bound extracellular polymeric substances (TB-EPS) and loosely bound EPS (LB-EPS) were effectively transported to soluble EPS (S-EPS). Furthermore, humification of organic matter occurred in S-EPS and LB-EPS when the dredged sediment was treated with EO/BDD-PS. Dominant hydroxyl radicals (•OH) and sulfate radicals (SO4•-) were generated in the EO/BDD-PS system. Moreover, the efficiency of the filtrate as an electrolyte decreased slightly after recycling five times. Therefore, this method may be economical for enhancing the dewaterability of dredged sediments.
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Affiliation(s)
- Feng Jiang
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Environmental Protection Key Laboratory for Lake Pollution Control, Chinese Research Academy of Environmental Sciences, Anwai, Beiyuan, Beijing 100012, China
| | - Xianlu Feng
- Beijing Key Lab for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Xia Jiang
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Environmental Protection Key Laboratory for Lake Pollution Control, Chinese Research Academy of Environmental Sciences, Anwai, Beiyuan, Beijing 100012, China.
| | - Pengfei Wang
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Environmental Protection Key Laboratory for Lake Pollution Control, Chinese Research Academy of Environmental Sciences, Anwai, Beiyuan, Beijing 100012, China.
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17
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Shaw K, Vogel M, Andriessen N, Hardeman T, Dorea CC, Strande L. Towards globally relevant, small-footprint dewatering solutions: Optimal conditioner dose for highly variable blackwater from non-sewered sanitation. J Environ Manage 2022; 321:115961. [PMID: 35998530 DOI: 10.1016/j.jenvman.2022.115961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 08/03/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
Globally, the sanitation needs of three billion people are met by non-sewered sanitation. Small-footprint treatment technologies are needed that are appropriate for dense urban areas. Blackwater (BW) (or fecal sludge), contains more than 95% liquid, and dewatering it without conditioning requires large footprints. Chemically-enhanced dewatering with conditioners is a promising option to increase dewatering performance and reduce required footprints. However, before implementation of this solution there is a need for increased knowledge on selection and dosing of conditioners. This study evaluated bio-based and synthetic conditioners (chitosan, tannin-, and starch-based, synthetic with and without poly-acrylamide) with 14 types of BW from five countries. The supernatant after settling with jar-tests was analyzed to quantify optimal dose and dewatering performance. The reduction of total chemical oxygen demand (COD) was >55%, achieved by removal of particulate constituents with mainly soluble COD remaining in the supernatant. A reduction in particulate COD could lead to increased efficiency of soluble COD in supernatant treatment. Bio-based conditioners are as effective as synthetic conditioners, and when performance was variable, it was due to differing properties of TSS, TS, EC and pH. Optimal conditioner dose for synthetic conditioners and chitosan could be predicted using concentrations of total solids (TS) (R2 > 0.7), whereas optimal dose for starch- and tannin-based conditioners could be predicted with electrical conductivity (EC) (R2 > 0.8), and colloid titration (R2 > 0.8). In addition, real-time optical TSS and EC sensors could accurately predict chitosan dose for fresh BW treated at source (R2 = 0.97, R2 = 0.95). This study validates that use of conditioners for dewatering with highly variable BW can be implemented with real-time measurements for optimal dose, in globally relevant implementations.
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Affiliation(s)
- Kelsey Shaw
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, Department of Sanitation, Water and Solid Waste for Development (Sandec), Überlandstrasse 133, 8600, Dübendorf, Switzerland; Department of Civil Engineering, University of Victoria, British Columbia, Canada.
| | - Michael Vogel
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, Department of Sanitation, Water and Solid Waste for Development (Sandec), Überlandstrasse 133, 8600, Dübendorf, Switzerland.
| | - Nienke Andriessen
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, Department of Sanitation, Water and Solid Waste for Development (Sandec), Überlandstrasse 133, 8600, Dübendorf, Switzerland.
| | - Thomas Hardeman
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, Department of Sanitation, Water and Solid Waste for Development (Sandec), Überlandstrasse 133, 8600, Dübendorf, Switzerland.
| | - Caetano C Dorea
- Department of Civil Engineering, University of Victoria, British Columbia, Canada.
| | - Linda Strande
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, Department of Sanitation, Water and Solid Waste for Development (Sandec), Überlandstrasse 133, 8600, Dübendorf, Switzerland.
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18
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Hidaka T, Nakamura M, Oritate F, Nishimura F. Comparative anaerobic digestion of sewage sludge at different temperatures with and without heat pre-treatment. Chemosphere 2022; 307:135808. [PMID: 35932923 DOI: 10.1016/j.chemosphere.2022.135808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/11/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
Anaerobic digestion of sewage sludge is generally conducted under mesophilic (around 35 °C) or thermophilic (around 55 °C) conditions, whereas it is conducted at lower temperatures in some wastewater treatment plants without heating. In this study, we compared the anaerobic digestion of sewage sludge at 15, 25, 30, 35, 45, and 55 °C following hyperthermophilic pre-treatment at 80 °C for 24 h. Laboratory-scale reactors were operated continuously for more than 1000 days, and batch experiments were performed to evaluate the reaction kinetics. Biogas production rates at 15 °C with and without pre-treatment divided by that at 35 °C without pre-treatment were 0.73 and 0.78, respectively. The dewaterability of the digested sludge was evaluated by the capillary suction time (CST). The CST was approximately 50 s at 15 °C with and without pre-treatment and was slower than the CST at 35 °C. Compared to the shear rate, viscosity was higher at lower temperatures; however, it decreased with pre-treatment, which reduced the energy required for mixing in the reactors. Pre-treatment eliminated Escherichia coli from the sludge; however, E. coli (approximately 105 colony forming unit/g-total solids) was detected after digestion at temperatures ≤30 °C. Pre-treatment was also useful to replace a part of heat treatment required for digested sludge before it was used as fertilizer. Gene sequencing analyses indicated the effects of pre-treatment and digestion temperature on the microbial community in the digested sludge. Co-generation of biogas is useful to obtain both electricity and heat; however, heat from co-generation is sometimes limited. To maximize electricity recovery, the use of low temperature digesters has the potential to reduce fuel costs. The results indicate that anaerobic digestion at low temperatures with or without heat pre-treatment can be an efficient and cost-effective method of treating sewage sludge.
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Affiliation(s)
- Taira Hidaka
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 615-8540, Japan.
| | - Masato Nakamura
- Institute for Rural Engineering, National Agriculture and Food Research Organization, Tsukuba, 305-8609, Japan
| | - Fumiko Oritate
- Institute for Rural Engineering, National Agriculture and Food Research Organization, Tsukuba, 305-8609, Japan
| | - Fumitake Nishimura
- Research Center for Environmental Quality Management, Graduate School of Engineering, Kyoto University, Otsu, 520-0811, Japan
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Wang J, Wang T, Li Z, Fu B, Zhai Y, Wang W, Zhai M, Chovelon JM, Gong Y, Wang H. Enhancement of sludge dewaterability by electrolysis coupled with peroxymonosulfate oxidation process: Performance, mechanisms and implications. Chemosphere 2022; 307:135865. [PMID: 35944688 DOI: 10.1016/j.chemosphere.2022.135865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/16/2022] [Accepted: 07/24/2022] [Indexed: 06/15/2023]
Abstract
With the rapid increase in waste activated sludge (WAS), it is urgent to develop appropriate dewatering processes to diminish sludge volume and improve disposal efficiency. In this study, an advanced oxidation process using electrolysis coupled with peroxymonosulfate (E/PMS) was applied to improve the dewaterability of WAS. The results indicated that the sludge water content (WC) and capillary suction time (CST) dropped from 98.4 ± 0.2% and 220.1 ± 2.3 s to 70.7 ± 0.8% and 63.0 ± 1.2 s, respectively, under the following conditions: an electrolysis voltage of 20 V, an electrolysis time of 20 min, and 200 mg/g TS PMS. The increase in sludge zeta potential, surface hydrophobicity, and flowability indicated a significant improvement in sludge dewaterability. SO4•-, O•H, and O21 generated in the E/PMS process were responsible for the improvement of WAS dewaterability. These reactive oxygen species damaged extracellular polymeric substances (EPS), decreased fluorescent EPS components, and transformed the extracellular protein secondary structures by influencing the H-bond actions that maintain the α-helix. The bound water content, and apparent viscosity of WAS were found to be reduced, which was also attributed to an increase in dewatering capacity. Additionally, E/PMS treatment enhanced the degradation of organic matter in sludge and reduced the toxicity of the filtrate as well as the bioavailability of heavy metals. The cost analysis found that the E/PMS process was relatively economical and has great potential for practical application.
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Affiliation(s)
- Junsen Wang
- College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Siping Rd 1239, Shanghai, 200092, China
| | - Tianrun Wang
- College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Siping Rd 1239, Shanghai, 200092, China
| | - Zonglin Li
- College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Siping Rd 1239, Shanghai, 200092, China
| | - Bomin Fu
- College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Siping Rd 1239, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, UNEP-TONGJI Institute of Environment for Sustainable Development, Shanghai, 200092, China
| | - Yuhui Zhai
- College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Siping Rd 1239, Shanghai, 200092, China
| | - Weijie Wang
- College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Siping Rd 1239, Shanghai, 200092, China
| | - Mudi Zhai
- College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Siping Rd 1239, Shanghai, 200092, China
| | - Jean-Marc Chovelon
- IRCELYON, CNRS UMR 5256, Université Claude Bernard Lyon 1, 2 Avenue Albert-Einstein, Villeurbanne, F-69626, France
| | - Yuxiu Gong
- College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Siping Rd 1239, Shanghai, 200092, China
| | - Hongtao Wang
- College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Siping Rd 1239, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, UNEP-TONGJI Institute of Environment for Sustainable Development, Shanghai, 200092, China.
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20
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Erdirencelebi D, Ebrahimi GM. Enhanced sewage sludge treatment via parallel anaerobic digestion at the upper mesophilic level. J Environ Manage 2022; 320:115850. [PMID: 36056485 DOI: 10.1016/j.jenvman.2022.115850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/21/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
Sewage mixed sludge (MS) digestion performance was ameliorated implementing the parallel digestion model for primary sludge (PS) and secondary sludge (SS) (waste activated sludge) as domestic sewage sludge fractions rich in oil and grease content at the upper mesophilic level (40 °C). Optimization of the organic loading rate (OLR) was conducted in parallel semi-continuous bench-scale digesters for PS, SS and MS. Comparatively evaluated performance and biosolid quality parameters were methane production rates, volatile solid (VS) reduction, oil and grease and nutrient content, dewaterability and electrical conductivity (EC). OLR optimization indicated different retention time needs for PS and SS stabilization and enabled 18% and 93% higher VS loading and reduction, respectively, compared to MS digestion. Inhibitory effect followed an ascending pattern as a result of OLR increase in each digestion line acting on the hydrolysis of proteinaceous matter and acetogenesis rather than methanogenesis. A high number of long chain fatty acids was detected in the raw sludges. The enhancing effect of the upper mesophilic temperature was significant in SS digestion with increased biodegradability, oil and grease removal and microbial growth compared to digestion at 35 °C. The parallel digestion system and upper mesophilic temperature proved a useful tool to enhance VS loading and reduction without worsening the stabilized biosolids' dewaterability as a feasible model in the existing and prospective municipal wastewater treatment plants (WWTPs). The weakness of the MS digestion was diagnosed as the lower synthesis degree of biomass induced by the dilution of the substrate in PS by SS mixing which weakened the microbial tolerance to high OLR and inhibition. The output indicated the potential of parallel AD, importance of the optimization for OLR and temperature to advance the performance and flexibility of the sludge line practice in municipal WWTPs.
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Affiliation(s)
- Dilek Erdirencelebi
- Konya Technical University, Engineering and Natural Sciences Faculty, Environmental Engineering Department, Selcuklu, 42500, Konya, Turkey.
| | - Gool Mohammad Ebrahimi
- Konya Technical University, Engineering and Natural Sciences Faculty, Environmental Engineering Department, Selcuklu, 42500, Konya, Turkey; Konya Technical University, Graduate Education Institute, Turkey
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21
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Yu Y, Li P, Zhu B, Liu Y, Yu R, Ge S. The application of sulfate radical-based advanced oxidation processes in hydrothermal treatment of activated sludge at different stages: A comparative study. Environ Sci Pollut Res Int 2022; 29:59456-59465. [PMID: 35386076 DOI: 10.1007/s11356-022-20038-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
Integrating hydrothermal treatment (HT) and advanced oxidation processes (AOP) was proved to be a promising approach for improving sludge dewaterability. In this study, the EPS valorization under elevated temperature and sulfate radical-based AOP were investigated to clarify the valorization of organic matter in different EPS layers and its effects on the sludge dewaterability. Results indicated that the organic matters in the inner layer of EPS decreased sharply with the elevated temperature, and released into the soluble EPS. Sulfate radical-based AOP significantly accelerated the degradation of organics and microbial cells lysis, especially in the presence of ZVI. The protein with the higher hydrophobicity was detected under the AOP enhanced HT. A better synergistic effect on sludge dewaterability was obtained by integrated the AOP at the initial hydrothermal stage. 3D-EEM and parallel factor analysis indicated that the protein and microbial by-product like substances in tightly bound EPS significantly affected the dewaterability.
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Affiliation(s)
- Yang Yu
- School of Energy and Environment, MOE Key Laboratory of Environmental Medicine Engineering, Southeast University, Nanjing, 210096, People's Republic of China.
| | - Panpan Li
- School of Energy and Environment, MOE Key Laboratory of Environmental Medicine Engineering, Southeast University, Nanjing, 210096, People's Republic of China
| | - Bingxing Zhu
- School of Energy and Environment, MOE Key Laboratory of Environmental Medicine Engineering, Southeast University, Nanjing, 210096, People's Republic of China
| | - Ye Liu
- College of Science and Technology, Hebei Agricultural University, No. 289 Lingyusi Street, Baoding, 071001, Hebei, People's Republic of China
| | - Ran Yu
- School of Energy and Environment, MOE Key Laboratory of Environmental Medicine Engineering, Southeast University, Nanjing, 210096, People's Republic of China
| | - Shifu Ge
- School of Energy and Environment, MOE Key Laboratory of Environmental Medicine Engineering, Southeast University, Nanjing, 210096, People's Republic of China
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22
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Wang Y, Gu M, Ge D, Dong Y, Bai L, Han Y, Zhu N. Polyhexamethylene biguanidine used as a new type sewage sludge conditioning agent: Effect on sludge dewaterability and mechanism. J Environ Manage 2022; 315:115146. [PMID: 35504185 DOI: 10.1016/j.jenvman.2022.115146] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 01/09/2022] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
Dewatering is the basic procedure of sludge treatment and disposal, and environmentally friendly and efficient sludge conditioning methods are urgently needed. Polyhexamethylene biguanide (PHMB), a broad-spectrum germicide used in daily life and medicine, was proposed as a sludge conditioning reagent in this paper, and its effect on waste activated sludge (WAS) dewaterability was studied for the first time. Results showed that PHMB can improve sludge dewatering performance, and capillary suction time (CST) and water content (Wc) of dewatered sludge cake was reduced by 78.11% and 13.37% with 100 mg PHMB/g dry sludge (DS). Further investigation revealed that the sludge properties changed pronouncedly after PHMB conditioning, the bound water content decreased from 1.58 g/g DS to 1.29 g/g DS, the particle size (D50) increased from 34.3 μm to 39.2 μm, the zeta potential increased from -20.96 mV to -3.36 mV, and the flowability increased whilst the viscosity decreased. When the dose of PHMB was lower than 50 mg/g DS, it mainly reacted with extracellular polymeric substance (EPS), resulting in a decrease in its content, which was also manifested by the decrease of molecular weights. However, when the dose reached 100 mg/g DS, PHMB would disrupt the cytomembranes of microorganisms and release cellular contents, reflected by a corresponding growth of EPS contents and the intensity of Fourier transform infrared (FTIR) spectrum. And the scanning electron microscope (SEM) images showed that PHMB conditioning made cracks and holes on sludge microstructures. The key mechanism of PHMB improving sludge dewaterability was inferred as "organic molecules disrupting" and "sludge particles flocculating". These findings demonstrate that PHMB is promising to be a novel, effective, and environmentally friendly sludge conditioning reagent.
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Affiliation(s)
- Yuhui Wang
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - MinXue Gu
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Dongdong Ge
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yanting Dong
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Lu Bai
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ying Han
- Jiangsu Welle Environmental Technology Co., Ltd., Jiangsu, 213022, China
| | - Nanwen Zhu
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, Shanghai, 200240, China.
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23
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Yan C, Zhan M, Xv K, Zhang S, Liang T, Yu R. Sludge dewaterability enhancement under low temperature condition with cold-tolerant Bdellovibrio sp. CLL13. Sci Total Environ 2022; 820:153269. [PMID: 35074377 DOI: 10.1016/j.scitotenv.2022.153269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 01/04/2022] [Accepted: 01/15/2022] [Indexed: 06/14/2023]
Abstract
The dewatering performance of waste activated sludge (WAS) is generally deteriorated under low temperature due to the increase of viscosity, which would exacerbate the difficulties in sludge treatment and disposal. In this study, the cold-tolerant Bdellovibrio sp. CLL13 was successfully screened for efficient sludge biolysis, and it dramatically improved the sludge dewaterability while no significant biolysis effects were observed for the mesophilic BALO strain at 12 °C. The reduction rates of the sludge capillary suction time (CST), the specific resistance of filtration (SRF), the sludge dry weight, and the fecal coliform bacteria concentration at the optimal reaction time of 14 h were 40.1 ± 0.2%, 69.6 ± 0.7%, 7.7 ± 0.4%, and 78.5 ± 0.4%, respectively, when the mixed liquid suspended solids (MLSS) content was between 10.8 and 29.6 g/L, the input dosage of CLL13 was 8.8 × 106 PFU/mL sludge, and the DO level was 1.2 mg/L. Meanwhile, the viscosity reduction rate, the relative hydrophobicity increasement rate, and the bound water reduction rate were 20.3 ± 1.2%, 6.9 ± 0.7%, and 29.4 ± 1.0%, respectively. The ratios of protein content to polysaccharides content in the extracellular polymeric substances (EPS) decreased significantly. In addition, the degradation of the macromolecular substances in EPS and the increase of the soluble chemical oxygen demand, the total nitrogen, the total phosphorus, and the lactate dehydrogenase levels were observed. Therefore, the cold-tolerant CLL13 induced the sludge biolysis and compromised the negative effects of low temperature on the sludge dewatering performance, which should be beneficial for the efficient WAS biolysis treatment application in the near future under low temperature.
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Affiliation(s)
- Chunhui Yan
- Department of Environmental Science and Engineering, School of Energy and Environment, Southeast University, Nanjing 210096, China
| | - Manjun Zhan
- Nanjing Research Institute of Environmental Protection, Nanjing Environmental Protection Bureau, Nanjing 210013, Jiangsu, China
| | - Kewei Xv
- Wuxi Xishan Water Group Co., Ltd., Wuxi 214101, Jiangsu, China
| | - Siyuan Zhang
- Department of Environmental Science and Engineering, School of Energy and Environment, Southeast University, Nanjing 210096, China
| | - Ting Liang
- Wuxi Xishan Water Group Co., Ltd., Wuxi 214101, Jiangsu, China
| | - Ran Yu
- Department of Environmental Science and Engineering, School of Energy and Environment, Southeast University, Nanjing 210096, China.
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24
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Wu B, Wang H, Li W, Dai X, Chai X. Influential mechanism of water occurrence states of waste-activated sludge: Potential linkage between water-holding capacity and molecular compositions of EPS. Water Res 2022; 213:118169. [PMID: 35180582 DOI: 10.1016/j.watres.2022.118169] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/22/2021] [Accepted: 02/07/2022] [Indexed: 05/06/2023]
Abstract
The water occurrence states in waste-activated sludge (WAS) are crucial to its dewaterability and significantly influenced by the water-retaining capacity of extracellular polymeric substances (EPS) matrix. Accordingly, the non-selective •OH-oxidation processes were widely reported for the sludge dewaterability improvement, just because it can non-selectively destruct complex structure units of EPS, no matter these structure units are crucial to EPS water-holding capacity or not. But these non-selective processes may also require the large consumption of oxidant chemicals, which limits their wide application. This study specifically focused on the •OH-induced variation in molecular compositions of EPS and the corresponding effects on water occurrence states of WAS, which is expected to lay a foundation for optimizing the efficiency of oxidation-based sludge conditioning. Especially, through a novel method based on the equilibrium dialysis with alkaline titration, the typical hydrophilic functional groups of EPS were quantitatively analyzed. The results indicated that the free amino group (-NH2) had the greater impact on the water-holding capacity of EPS than the acidic hydroxyl groups (-OH). Nevertheless, by Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS), the hydrophilic heteroatom classes (e.g. N:Cw) were found to be less sensitive to the varying oxidant dosage than the molecular saturation degree (e.g. weighted averages of double bond equivalents (DBEw) and aromatic index (AImod,w)). •OH modified the nitrogen-containing or oxygen-containing functional groups, but could not completely remove these hydrophilic functional groups from EPS macromolecules. Therefore, the potential competition for •OH between the hydrophilic functional groups and the unsaturated structure units of EPS was clarified, which guides directions that developing highly-efficient sludge conditioning approaches should be based on the selective removal of hydrophilic functional groups instead of improving •OH production efficiency.
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Affiliation(s)
- Boran Wu
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Hao Wang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Wenxuan Li
- NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, #02-01 T-Lab Building, 117411, Singapore
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
| | - Xiaoli Chai
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
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25
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Wang HF, Qi HY, Lian ZH, Zhang YL, Li J, Zeng RJ. A unified operating procedure is crucial to evaluate sludge dewaterability, taking the setup of refrigerated storage time as an example. J Environ Manage 2022; 307:114528. [PMID: 35091248 DOI: 10.1016/j.jenvman.2022.114528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 01/08/2022] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
Although extensive efforts have been carried out to study sludge dewatering mechanism, the lack of universal operating procedures makes it never be satisfactorily explained. This study evaluated the impact of a unified operating procedure on waste activated sludge (WAS) dewaterability by taking the setup of refrigerated storage time as an example. It was found that storage time played an important role in determining WAS dewaterability and sampled WAS should be refrigerated within 2 days. The results showed that after 2-d storage, sludge filterability was deteriorated significantly while the extent of dewatering efficiency had little change. Meanwhile, increasing storage time greatly increased the release of extracellular polymeric substances (EPS) and heavy metals, decreased sludge viscosity and weakened its network strength, but had little impact on the floc size and zeta potential of the sludge samples. It can hardly reveal the mechanism of storage time on sludge dewaterability due to the non-uniformity of operating procedures in literatures, which is normally ignored. This study emphasizes a unified operating procedure is crucial to evaluate WAS dewaterability. Therefore, more efforts shall be focused on establishing the uniform operating procedure while advancing applied research in the field of sludge dewatering.
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Affiliation(s)
- Hou-Feng Wang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Hui-Yun Qi
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Ze-Han Lian
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Ya-Li Zhang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Jing Li
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.
| | - Raymond Jianxiong Zeng
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.
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26
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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27
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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. Environ Sci Pollut Res Int 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] [What about the content of this article? (0)] [Affiliation(s)] [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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28
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Yu Y, Li P, Zhang J, Li J, Yu R. Comprehensive insights into the organic fractions on solid-liquid separation performance of anaerobic digestates from food waste. Sci Total Environ 2021; 800:149608. [PMID: 34426318 DOI: 10.1016/j.scitotenv.2021.149608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 07/28/2021] [Accepted: 08/08/2021] [Indexed: 06/13/2023]
Abstract
Anaerobic digestion (AD) is an effective approach for food waste treatment and valorization. However, AD is limited by proper disposal of the food waste digestates in megacities. The objective of this study was to elucidate the dominant factors on solid-liquid separation performance of the digestates from food wastes. Results indicated that the composition differences in organic fractions showed significant impacts on solid-liquid separation performance by comparing the digestates from different cities in China. Dissolved organic matter (DOM), especially for proteins and carbohydrates, varied between the digestates in various cities, which may lead to the difference in solid-liquid separation performance. Digestate with lowest proteins (33.86 mg/L) from Shanghai's food waste AD plant had the best dewatering performance. In contrast, digestate from Nanjing's food waste AD plant showed the worst dewatering performance. Pearson's correlation analysis indicated that there is a significant correlation between soluble protein and the dewaterability of digestates (R2 > 0.9573, p < 0.03), the lower soluble protein achieved higher dewaterability of digestates.
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Affiliation(s)
- Yang Yu
- Department of Environmental Science and Engineering, School of Energy and Environment, Southeast University, No. 2 Sipailou Street, Nanjing 210096, China; Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing 210009, China.
| | - Panpan Li
- Department of Environmental Science and Engineering, School of Energy and Environment, Southeast University, No. 2 Sipailou Street, Nanjing 210096, China; Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing 210009, China
| | - Jingxue Zhang
- Department of Environmental Science and Engineering, School of Energy and Environment, Southeast University, No. 2 Sipailou Street, Nanjing 210096, China; Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing 210009, China
| | - Jie Li
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Ran Yu
- Department of Environmental Science and Engineering, School of Energy and Environment, Southeast University, No. 2 Sipailou Street, Nanjing 210096, China; Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing 210009, China
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29
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Zhang W, Dong B, Dai X, Dai L. Enhancement of sludge dewaterability via the thermal hydrolysis anaerobic digestion mechanism based on moisture and organic matter interactions. Sci Total Environ 2021; 798:149229. [PMID: 34325135 DOI: 10.1016/j.scitotenv.2021.149229] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/20/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
It is known that sludge dewaterability improves during the thermal hydrolysis process (THP); however, the effect of thermal hydrolysis and anaerobic digestion (THP-AD) on sludge dewaterability is unclear. Further, the difference between thermal hydrolysis as pre-treatment for anaerobic digestion (pre-THP-AD) and as post-treatment (post-THP-AD) is also unclear. Based on the evolution of the interaction between organic matter and moisture, the mechanism of pre-THP-AD and post-THP-AD improving the sludge dewaterability was explored. The capillary suction time values of pre-THP-AD and post-THP-AD increased by 58% and 59%, respectively, and the proportion of free moisture increased by 10.44% and 10.59%, respectively, compared with the conventional anaerobic digestion (CAD) process. The cell structure was destroyed and most organic matter was converted into dissolved form through THP, organic matter degraded during AD, the interaction between moisture and organic matter declined, and the mechanically bound moisture transformed into free moisture. Additionally, the intensity of hydrophilic functional groups, such as amide I decreased and amide II disappeared after (pre- and post-) THP-AD. The surface hydrophobicity of sludge samples was enhanced and sludge dewaterability improved. The mechanism of pre-/post-THP-AD enhanced sludge dewaterability based on the interaction between moisture and organic matter; additionally, this will provide a reference for optimised moisture-sludge separation processes and guidance for the optimisation of engineering operation parameters.
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Affiliation(s)
- Wei Zhang
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Bin Dong
- School of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Xiaohu Dai
- School of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
| | - Lingling Dai
- School of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
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Wang G, Ge D, Bai L, Dong Y, Bian C, Xu J, Zhu N, Yuan H. Insight into the roles of electrolysis-activated persulfate oxidation in the waste activated sludge dewaterability: Effects and mechanism. J Environ Manage 2021; 297:113342. [PMID: 34314959 DOI: 10.1016/j.jenvman.2021.113342] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/12/2021] [Accepted: 07/18/2021] [Indexed: 06/13/2023]
Abstract
Sludge dewatering, as one of the most important steps of sludge treatment, can facilitate transportation and improve disposal efficiency by reducing the volume of sludge. This study investigated the effects of electrolysis-activated persulfate oxidation on improving sludge dewaterability. The results indicated that the sludge capillary suction time (CST) and water content of dewatered sludge cake (Wc) reduced from 93.7 s and 87.8% to 9.7 s and 68.3% respectively at the optimized process parameters: electrolysis voltage of 40 V, electrolysis time of 20 min, and 1.2 mmol/g TS S2O82-. Correlation analysis revealed that the enhancement of sludge dewaterability was closely associated with the increased floc size and zeta potential, decreased protein content in three-layers extracellular polymeric substances (EPS) and viscosity (R = -0.868, p = 0.002; R = -0.703, p = 0.035; R ≥ 0.961, p < 0.001; R = 0.949, p < 0.001). Four protein fluorescence regions in EPS were analyzed by three-dimensional excitation-emission matrix parallel factor (3D-EEM-PARAFAC). The protein secondary structure was changed after the treatment, and the reduction of α-helix/(β-sheet + random coil) indicated that more hydrophobic sites were exposed. Analysis by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and rheological test demonstrated that the hydrophilic functional groups of the sludge were decreased and the sludge mobility was significantly enhanced after the treatment with electrolysis-activated persulfate oxidation. Moreover, bound water was converted to free water during SO4·- and ·OH generated by electrolysis-activated persulfate degraded EPS and attacked sludge cells. Meanwhile, scanning electron microscopy (SEM) images revealed that the treated sludge formed porous channel structures, which promoted the flowability of the water. These findings provide a new insight based on electrolysis-activated persulfate oxidation in sludge treatment for enhancing sludge dewaterability.
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Affiliation(s)
- Guanjun Wang
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Dongdong Ge
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Lu Bai
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yanting Dong
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Chang Bian
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jiajia Xu
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Nanwen Zhu
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Haiping Yuan
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
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Wang Z, Liu T, Duan H, Song Y, Lu X, Hu S, Yuan Z, Batstone D, Zheng M. Post-treatment options for anaerobically digested sludge: Current status and future prospect. Water Res 2021; 205:117665. [PMID: 34547700 DOI: 10.1016/j.watres.2021.117665] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/15/2021] [Accepted: 09/10/2021] [Indexed: 05/16/2023]
Abstract
Anaerobic digestion is the most commonly used sludge treatment technology in large-scale wastewater treatment plants (WWTPs), generating two main products, i.e., biogas and anaerobically digested (AD) sludge. Biogas can be used as a source of renewable energy, and AD sludge is often transported for agricultural land application. Land application of AD sludge is confronted with ever-increasing economic and regulatory pressures due to its high water content, high organic content and related odour and pathogen content (if poorly stabilized), as well as potential toxic metal and organic contaminants. To address these challenges, a number of technologies have been developed for the further treatment of AD sludge before final disposal. This review aims to critically evaluate these state-of-the-art technologies. These technologies were categorized based on their primary aims: 1) dewaterability enhancement; 2) solids reduction and stabilization; 3) toxic metals removal. At present, the goal of post-treatment mainly focuses on dewaterability enhancement, to reduce transport costs. In future, we propose that the post-treatment of AD sludge should orient towards multiple aims, i.e., an integrated approach enabling sludge volume reduction, stabilization (including pathogen removal), and metal solubilization simultaneously. Two promising technical routes are suggested as examples, i.e. physio-chemical iron-based advanced oxidation and biological acidic aerobic digestion, while more approaches need to be developed in future studies. We concluded that post-treatment of AD sludge will promote the AD sludge management towards a more economically favourable, socially acceptable, and environmentally sustainable way; however, further development and rigorous evaluation are required for a wider adoption.
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Affiliation(s)
- Zhiyao Wang
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Tao Liu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Haoran Duan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Yarong Song
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Xi Lu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Damien Batstone
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Min Zheng
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
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Cai G, Ebrahimi M, Zheng G, Kaksonen AH, Morris C, O'Hara IM, Zhang Z. Effect of ferrous iron loading on dewaterability, heavy metal removal and bacterial community of digested sludge by Acidithiobacillus ferrooxidans. J Environ Manage 2021; 295:113114. [PMID: 34171779 DOI: 10.1016/j.jenvman.2021.113114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/13/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
Acidithiobacillus ferrooxidans ILS-2 was adapted in digested sludge and used to treat sludge for dewaterability improvement. Results showed that increasing ferrous iron loading increased sludge dewaterability, but the inoculation of the bioleaching strain had little effect on sludge dewaterability compared to controls without the strain. The total extracellular polymeric substances (EPS) contents of sludges with and without bioleaching treatment were similar except for bioleaching treatment at 10% ferrous iron loading (on sludge total solids) where total EPS was higher with bioleaching treatment. However, bioleaching treatment for 48 h had a notable effect on removal of heavy metals, such as Mn, Ni and Zn, especially at the high loadings of ferrous iron. In the presence of A. ferrooxidans, the removal of Ni, Mn and Zn reached 93%, 88% and 80%, respectively, at a ferrous iron loading of 21%. The sequencing of 16S rRNA genes indicated that increasing ferrous iron loadings to 15% and 21% increased the relative abundance of Acidithiobacillus, Acidocella (with A. ferrooxidans) and Carboxylicivirga (without A. ferrooxidans) but decreased the abundance of Pseudomonas and Acinetobacter after 48 h treatment. This study enhanced the understanding of the correlations between bioleaching treatment of digested sludge, sludge dewaterability, heavy metal removal and bacterial communities.
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Affiliation(s)
- Guiqin Cai
- Centre for Agriculture and the Bioeconomy, Faculty of Science, Queensland University of Technology, Brisbane, QLD 4000, Australia; School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Majid Ebrahimi
- Centre for Agriculture and the Bioeconomy, Faculty of Science, Queensland University of Technology, Brisbane, QLD 4000, Australia; School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Guanyu Zheng
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Anna H Kaksonen
- Commonwealth Scientific and Industrial Research Organisation, Land and Water, Wembley, WA 6913, Australia
| | - Christina Morris
- Commonwealth Scientific and Industrial Research Organisation, Land and Water, Wembley, WA 6913, Australia
| | - Ian M O'Hara
- Centre for Agriculture and the Bioeconomy, Faculty of Science, Queensland University of Technology, Brisbane, QLD 4000, Australia; School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia; ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, QLD 4000, Australia
| | - Zhanying Zhang
- Centre for Agriculture and the Bioeconomy, Faculty of Science, Queensland University of Technology, Brisbane, QLD 4000, Australia; School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia; ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, QLD 4000, Australia.
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She Y, Wei W, Ai X, Hong J, Xin X. Synergistic pretreatment of CaO and freezing/thawing to enhance volatile fatty acids recycling and dewaterability of waste activated sludge via anaerobic fermentation. Chemosphere 2021; 280:130939. [PMID: 34162110 DOI: 10.1016/j.chemosphere.2021.130939] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/04/2021] [Accepted: 05/18/2021] [Indexed: 06/13/2023]
Abstract
To avoid the generally deteriorated dewaterability of sludge in waste activated sludge (WAS) anaerobic acidogenesis, the combination of varied calcium oxide (CaO) dosage (i.e., 0.01-0.07 g/g TS) and freezing/thawing pretreatment (5 F/T cycles) was investigated for concurrently improving the production of volatile fatty acids (VFAs) and dewatering performance of sludge. The highest release of soluble chemical oxygen demand (SCOD) (1836 ± 96 mg/L) and accumulation of VFAs (448.0 mg COD/g VS) were reached through the co-pretreatment of CaO (0.07 g/g TS) and F/T (50 h at -24 °C) (i.e., 0.07 CaO-F/T). Meanwhile, optimal dewaterability of sludge was also achieved in 0.07 CaO-F/T co-pretreated WAS fermentation, which was reflected by large particle size (98.32 μm), low capillary suction time (41.6 s), decreased specific resistance to filtration (SRF, reduced 47.5% against blank) and high zeta potential (-9.59 mV). Co-pretreatment of CaO and F/T reduced the species number of total microbial population, but improved the abundance of acid-producing bacteria. Increased abundance of Bacteroides, Macellibacteroides, Petrimonas, Prevotella, Clostridium, and Megasphaera was positively relevant to the high yields of VFAs. The economic analysis indicated that CaO-F/T was economically acceptable with considerable estimated net profits, which provided a feasible and efficient alternative for further WAS treatment at large scale.
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Affiliation(s)
- Yuecheng She
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen, 361021, China; Xiamen Engineering Research Center of Industrial Wastewater Biochemical Treatment, Xiamen, 361021, China; Fujian Provincial Research Center of Industrial Wastewater Biochemical Treatment (Huaqiao University), Xiamen, 361021, China
| | - Wenxuan Wei
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen, 361021, China; Xiamen Engineering Research Center of Industrial Wastewater Biochemical Treatment, Xiamen, 361021, China; Fujian Provincial Research Center of Industrial Wastewater Biochemical Treatment (Huaqiao University), Xiamen, 361021, China
| | - Xiaohuan Ai
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen, 361021, China; Xiamen Engineering Research Center of Industrial Wastewater Biochemical Treatment, Xiamen, 361021, China; Fujian Provincial Research Center of Industrial Wastewater Biochemical Treatment (Huaqiao University), Xiamen, 361021, China
| | - Junming Hong
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen, 361021, China; Xiamen Engineering Research Center of Industrial Wastewater Biochemical Treatment, Xiamen, 361021, China; Fujian Provincial Research Center of Industrial Wastewater Biochemical Treatment (Huaqiao University), Xiamen, 361021, China.
| | - Xiaodong Xin
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen, 361021, China; Xiamen Engineering Research Center of Industrial Wastewater Biochemical Treatment, Xiamen, 361021, China; Fujian Provincial Research Center of Industrial Wastewater Biochemical Treatment (Huaqiao University), Xiamen, 361021, China.
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Liu H, Li X, Zhang Z, Nghiem LD, Gao L, Wang Q. Semi-continuous anaerobic digestion of secondary sludge with free ammonia pretreatment: Focusing on volatile solids destruction, dewaterability, pathogen removal and its implications. Water Res 2021; 202:117481. [PMID: 34358904 DOI: 10.1016/j.watres.2021.117481] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/15/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
Our previous work has reported the pretreatment of secondary sludge with free ammonia (NH3, FA) enhanced the methane production in batch biochemical methane potential tests. However, the batch biochemical methane potential test could only provide conservative results compared to continuous/semi-continuous anaerobic digestion. Also, the impacts of FA pretreatment on the key anaerobic digestion parameters, including volatile solids (VS) destruction, sludge dewaterability and pathogen removal, are still unknown. This study for the first time investigated these impacts using semi-continuous anaerobic digestion systems for 130 days. Pretreatment of secondary sludge for 24 h at an FA concentration of 560 mg NH3-N/L improved VS destruction by 26.4% (from 22.0 to 27.8%), supported by a similar increase of 28.6% in methane production (from 126.7 to 162.9 ml CH4/g VSfed). Model based analysis revealed that FA pretreatment improved the sludge degradability extent, which may be the reason for the enhanced VS destruction. Equally importantly, the dewaterability of the digested sludge with FA pretreatment was also enhanced by 9.2% (from 12.0 to 13.1% in solids content of the dewatered digested sludge), which could be partly attributed to the increased zeta potential from -16.7 to -14.5 mV. Anaerobic digestion with FA pretreatment enhanced the removals of Fecal Coliform and E. Coli by 1.3 and 1.4 log MPN/g TS (MPN: Most Probable Number; TS: Total Solids), indicating FA pretreatment was effective in enhancing pathogen removal. With inorganic solids representing 21% of the sludge used, the volume of dewatered sludge to be disposed of was reduced by 14.5% via FA pretreatment. This will substantially decrease the cost as evaluated by economic analysis. In brief, this study provides a promising strategy to enhance sludge reduction in anaerobic digestion and is of great significance in promoting the application of FA pretreatment strategy in the real world.
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Affiliation(s)
- Huan Liu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Xuan Li
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zehao Zhang
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Long D Nghiem
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Li Gao
- South East Water, 101 Wells Street, Frankston, VIC 3199, Australia
| | - Qilin Wang
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia.
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Zhang D, Wang Y, Li J, Fan X, Li E, Dong S, Yin W, Wang D, Shi B. Electrical impedance spectroscopy as a potential tool to investigate the structure and size of aggregates during water and wastewater treatment. J Colloid Interface Sci 2021; 606:500-509. [PMID: 34403859 DOI: 10.1016/j.jcis.2021.08.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 10/20/2022]
Abstract
Microscopic structure and size are important metrics for estimating aggregates environmental behaviors during water and wastewater treatment. However, in-situ determination of these characteristics is still a challenge. Here, we drew inspiration from a block disassembly process to propose an electrical impedance spectroscopy (EIS) method and constructed a generalized framework to associate macroscale electrical properties with microscopic structure and size-related characteristics of aggregates of different hierarchies. Extracted via EIS, the proposed models were verified to be capable of describing the self-similarity of aggregates and capturing the fractal and size information. Further, the proposed models exhibited a wide range of applications, which agrees well with the data gathered from various activated sludges, other colloids, and microgels in water and wastewater treatment. Finally, the EIS method was achieved online monitoring of fractal dimension and floc size during a sludge pre-oxidation conditioning process, which was elected as an example to illustrate the potential online applications of this EIS method in real water and wastewater environment. The obtained on-line data were used to indicate the potential suitable oxidation time during sludge pre-oxidation conditioning. These observations may inspire new methods of quantifying the aggregate structure and promote intelligent and dynamic decision-making during water and wastewater treatment.
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Affiliation(s)
- Daxin Zhang
- College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China
| | - Yili Wang
- College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China.
| | - Junyi Li
- College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China
| | - Xiaoyang Fan
- College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China
| | - Enrui Li
- College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China
| | - Shuoxun Dong
- Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100083, China
| | - Weiwen Yin
- School of Water Resources and Environment, MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Dongsheng Wang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Baoyou Shi
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
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Liu H, Yang K, Luo L, Lu Q, Wu Y, Lan M, Luo Y, Liang W. Study on bioleaching of heavy metals and resource potential from tannery yard sludge. Environ Sci Pollut Res Int 2021; 28:38867-38879. [PMID: 33745044 DOI: 10.1007/s11356-021-13425-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 03/09/2021] [Indexed: 06/12/2023]
Abstract
Tannery sludge that has accumulated in the natural environment of a tannery industrial zone for a long time contains large amounts of toxic heavy metal elements such as Cr, which has a serious impact on the surrounding environment. This study used indigenous acidophilic sulfur-oxidizing bacteria from local tannery wastewater treatment plants to examine the effects of bioleaching on the removal of heavy metals in local tannery sludge accumulated in the natural environment. The effect of pre-oxygenation on bioleaching was investigated, and trends of sludge dewaterability during bioleaching and changes in the total amount of heavy metals, total nitrogen (TN), and total phosphorus (TP) during bioleaching were determined. Changes in the contents of different bound forms of heavy metals in tannery yard sludge during the bioleaching process were revealed. The experimental results showed that pre-oxygenation treatment of tannery yard sludge can shorten the bioleaching period (by at least 4 days) and improve the removal efficiency of all heavy metals. To ensure sludge dewaterability, the pH of the leaching system at the end of the bioleaching must not be lower than 1.67. The main components of heavy metals were stable in the tannery yard sludge, which critically affected the final removal efficiency of all heavy metals. The dissolution process of heavy metals showed that the morphology of heavy metals changed from stable to unstable forms in the bioleaching process, further dissolving into the liquid phase to be removed. In this experiment, the removal efficiency of all heavy metals in the tannery yard sludge was higher than 88.49%, and these heavy metals had good stability in morphology (the stable forms accounted for more than 87% of the total). In addition, the TN content in the remaining sludge was 27.9 g/kg, which is much higher than fertilizer TN requirements, indicating a high potential for resource utilization. Therefore, the method of bioleaching to remove heavy metals in tannery yard sludge for reuse is worthy of in-depth study and promotion.
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Affiliation(s)
- Hang Liu
- College of Resources and Environment Engineering, Guizhou University, Guiyang, 550025, China
| | - Kaizhi Yang
- College of Resources and Environment Engineering, Guizhou University, Guiyang, 550025, China
| | - Lingfeng Luo
- College of Resources and Environment Engineering, Guizhou University, Guiyang, 550025, China
| | - Qian Lu
- College of Resources and Environment Engineering, Guizhou University, Guiyang, 550025, China
| | - Yonggui Wu
- College of Resources and Environment Engineering, Guizhou University, Guiyang, 550025, China.
- Institute of Applied Ecology Guizhou University, Guiyang, 550025, China.
- Guizhou Karst Environmental Ecosystem Observation and Research Station, Ministry of Education, Guiyang, 550025, China.
| | - Meiyan Lan
- College of Resources and Environment Engineering, Guizhou University, Guiyang, 550025, China
| | - Youfa Luo
- College of Resources and Environment Engineering, Guizhou University, Guiyang, 550025, China
| | - Wan Liang
- Shanghai Guohui Environmental Technology Group Co., Ltd., Shanghai, 201100, China
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Liang J, Zhang L, Zhou Y. Pyrite assisted peroxymonosulfate sludge conditioning: Uncover triclosan transformation during treatment. J Hazard Mater 2021; 413:125368. [PMID: 33609874 DOI: 10.1016/j.jhazmat.2021.125368] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/23/2021] [Accepted: 02/07/2021] [Indexed: 06/12/2023]
Abstract
Waste activated sludge (WAS) dewatering is a crucial process for sludge treatment and disposal. In this study, we proposed a novel pyrite (FeS2) and peroxymonosulfate (PMS) treatment to improve WAS dewaterability. Micropollutants are commonly enriched in the sludge. It is not clear if the micropollutants remain in the sludge during the conditioning. Triclosan (TCS) as a widely used bactericide often presents in the WAS, thus was chosen as a target micropollutant. Pyrite + PMS treatment could simultaneously enhance WAS dewaterability and TCS removal with low cost and high benefit. Under the optimal conditions, the specific resistance of filtration (SRF) and capillary suction time (CST) were reduced by 84.60% and 74.91%, respectively. Meanwhile, the TCS removal efficiency was 34.08% with four transformation products identified. During the pyrite + PMS process, sulfate radicals and hydroxyl radicals were generated and strong flocculation was induced by iron. These two processes significantly reduced the sticky biopolymers, hydrophilic functional groups, and hydrophilic protein molecular structure of extracellular polymeric substances (EPS), leading to the release of bound water and TCS. Collectively, the pyrite + PMS treatment is a promising alternative for simultaneous enhancement of WAS dewatering and micropollutants removal, which is beneficial to the downstream treatment.
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Affiliation(s)
- Jialin Liang
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 637141, Singapore; Institute of Bioresource and Agriculture, Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Liang Zhang
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 637141, Singapore
| | - Yan Zhou
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, 639798, Singapore.
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38
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Arenas CB, González R, González J, Cara J, Papaharalabos G, Gómez X, Martínez EJ. Assessment of electrooxidation as pre- and post-treatments for improving anaerobic digestion and stabilisation of waste activated sludge. J Environ Manage 2021; 288:112365. [PMID: 33765574 DOI: 10.1016/j.jenvman.2021.112365] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 07/24/2020] [Accepted: 03/11/2021] [Indexed: 05/16/2023]
Abstract
This study evaluates the effects of electro-oxidation as a means for enhancing sludge stabilisation. Boron-doped diamond electrodes were used to treat waste activated sludge and digestate under different operating parameters (current density, conductivity, pH, and time). Electro-oxidation runs affected the solubilisation of organic matter, which seemed to improve anaerobic digestion and dewaterability characteristics. Among the tested parameters, pre-treating sludge via electro-oxidation under alkaline conditions (Treatment T5) resulted in the highest increase in soluble organic material compared to that in the control, with total organic carbon (TOC) and soluble chemical oxygen demand (COD) values of 2753 and 7819 mg L-1, respectively (control TOC and COD values were 385 and 1073 mg L-1). This pretreatment also achieved a high hydrolysis rate (higher concentration in volatile fatty acids) with a concomitant increase in methane yield (approximately 18%). On the other hand, the application of electro-oxidation as a post-treatment for improving digestate dewaterability resulted in noticeable changes in the release of water during drying due to protein and aliphatic matrix modification of the sample.
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Affiliation(s)
- Cristian B Arenas
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain
| | - Ruben González
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain
| | - Judith González
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain
| | - Jorge Cara
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain
| | - George Papaharalabos
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain
| | - Xiomar Gómez
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain
| | - E Judith Martínez
- Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, Av. de Portugal 41, 24009, León, Spain.
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Wang Q, Xu Q, Du Z, Zhang W, Wang D, Peng Y. Mechanistic insights into the effects of biopolymer conversion on macroscopic physical properties of waste activated sludge during hydrothermal treatment: Importance of the Maillard reaction. Sci Total Environ 2021; 769:144798. [PMID: 33465628 DOI: 10.1016/j.scitotenv.2020.144798] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 11/30/2020] [Accepted: 12/21/2020] [Indexed: 06/12/2023]
Abstract
In this study, the molecular transformation of sludge biopolymers during hydrothermal treatment with the temperature ranging from 25 °C to 200 °C was examined and was seen to significantly affect the macrophysical properties (dewaterability and rheological property) of sludge. The results showed that the sludge dewaterability and flow ability under high shear stress deteriorated by a hydrothermal process at 25 °C to 120 °C, but the deterioration alleviated above the temperature threshold of 120 °C. The consistence of changes in sludge dewaterability and rheological property in HT process was mainly attributed to the variation in gel properties of soluble biopolymer. Two-stage changes in biopolymer transformation were identified, beginning with a solubilization stage from 25 °C to 120 °C in which a biopolymer with a gel-like network structure was released into liquid phase, creating flow resistance under high shear stress such that sludge dewaterability deteriorated. The second stage was identified as a conversion stage (120 °C-200 °C) in which proteins and polysaccharides hydrolyzed and experienced a Maillard reaction, leading to the degradation of the biopolymer network structure. The newly formed recalcitrant Maillard products showed weak flow response to high shear stress, allowing for an improvement in sludge dewaterability. The pathways of a Maillard reaction were identified via gas chromatography-mass spectrometer (GC-MS), 1H nuclear magnetic resonance spectroscopy (1H NMR) and two-dimensional correlation spectral analysis (2D-COS) of Fourier-transform infrared spectrometer (FTIR), etc. Three-dimensional excitation-emission matrix (3D-EEM) proved to be an applicable method for tracking Maillard reaction in sludge hydrothermal process due to the distinctive fluorescence characteristics of Maillard products. This study further clarifies the obscure process of sludge hydrothermal treatment and will help improve the accuracy of subsequent research.
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Affiliation(s)
- Qiandi Wang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Qiongying Xu
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Zhengliang Du
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Weijun Zhang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China.
| | - Dongsheng Wang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China
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Yu W, Wan Y, Wang Y, Zhu Y, Tao S, Xu Q, Xiao K, Liang S, Liu B, Hou H, Hu J, Yang J. Enhancing waste activated sludge dewaterability by reducing interaction energy of sludge flocs. Environ Res 2021; 196:110328. [PMID: 33075357 DOI: 10.1016/j.envres.2020.110328] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/28/2020] [Accepted: 10/09/2020] [Indexed: 06/11/2023]
Abstract
How to efficiently improve waste activated sludge (WAS) dewaterability is a common challenge in WAS treatment and management throughout world. The interaction energy of sludge flocs is of great importance for sludge dewaterability. In this study, the relationship among the repulsive force of sludge flocs, hydrophilic/hydrophobic characteristics of sludge flocs, and sludge dewaterability have been quantitatively and qualitatively investigated based on extended Derjaguin-Landau-Verwey-Overbeek theory for the first time. The energy barrier of sludge flocs has good correlations with sludge dewaterability (p < 0.05). Trivalent cations (Al3+ and Fe3+) and Fenton's reagent reduced the interfacial free energy (ΔG) from 9.4 mJ/m2 of raw sludge to -34.2 (Al3+), -60.5 (Fe3+), and -63.2 (Fenton) mJ/m2, respectively, indicating that the hydrophilic surfaces of the sludge flocs converted to hydrophobic (△G < 0), and decreasing Lewis acid-base interaction energy (WAB) of sludge flocs. In addition, most of the trivalent cations (Al3+ and Fe3+) were attached to sludge flocs, leading to neutralize negative charges and mitigate electrostatic interaction energy (WR) of sludge flocs. The reduction of WAB and WR eliminated energy barrier of sludge flocs and repulsive force between sludge flocs. In comparison, monovalent (Na+ and K+) and bivalent (Ca2+ and Mn2+) cations cannot completely change the hydrophilic surface characteristic and negative charge of sludge flocs. The existed energy barrier prevented sludge flocs to agglomerate with each other, thus resulting in a worse dewaterability. This study illustrated that reducing interaction energy of sludge flocs played a critical role to improve sludge dewaterability.
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Affiliation(s)
- Wenbo Yu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei, 430074, China
| | - Yanlei Wan
- Changjiang Institute of Survey, Planning, Design and Research, Wuhan, Hubei, 430010, China
| | - Yu Wang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei, 430074, China
| | - Yuwei Zhu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei, 430074, China
| | - Shuangyi Tao
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei, 430074, China
| | - Qi Xu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei, 430074, China; Changjiang Institute of Survey, Planning, Design and Research, Wuhan, Hubei, 430010, China
| | - Keke Xiao
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei, 430074, China
| | - Sha Liang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei, 430074, China
| | - Bingchuan Liu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei, 430074, China
| | - Huijie Hou
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei, 430074, China.
| | - Jingping Hu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei, 430074, China
| | - Jiakuan Yang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei, 430074, China; State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China.
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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. Environ Sci Pollut Res Int 2021; 28:13300-13311. [PMID: 33175353 DOI: 10.1007/s11356-020-11562-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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42
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Ruan S, Deng J, Cai A, Chen S, Cheng Y, Li J, Li Q, Li X. Improving dewaterability of waste activated sludge by thermally-activated persulfate oxidation at mild temperature. J Environ Manage 2021; 281:111899. [PMID: 33418390 DOI: 10.1016/j.jenvman.2020.111899] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 12/08/2020] [Accepted: 12/23/2020] [Indexed: 06/12/2023]
Abstract
The mass production of waste activated sludge in wastewater treatment plants may lead to environmental pollution and sludge dewatering is an essential process during its treatment. The oxidation of extracellular polymeric substances (EPS) was the core step to achieve deep sludge dewatering. In this study, thermally-activated sodium persulfate (SPS) process was managed to improve the dewaterability of waste activated sludge (WAS) and its internal mechanism was systematically elaborated. Experimental results showed that with 2.0 mmol/g VSS SPS at 80 °C, capillary suction time (CST) was roughly 59.74% of that in raw sludge. Under this condition, 14.66 ± 0.10 × 1011 kg/m of specific resistance to filtration (SRF) and 61.8% ± 0.1% of water content (WC) was determined, respectively. A solubilization/oxidation process was proposed to unravel the mechanism of the enhanced dewaterability of WAS in thermally-activated SPS process. Mild temperature efficiently disrupted the sludge flocs and broke cell walls, releasing large amounts of EPS into bulk phase. Meanwhile, mild temperature accelerated the decomposition of SPS to generate sulfate radicals (SO4-) and hydroxyl radicals (OH) for oxidizing EPS, facilitating the conversion of bound hydrated water into free water and achieving solid-water separation. The higher reaction temperature favored sludge dewatering, whereas overdosing SPS posed no significant impact. Further analysis illustrated that tyrosine protein-like, tryptophan protein-like, fulvic acid-like and humic acid-like substances in various EPS fractions together exerted the influence on sludge dewatering. Furthermore, the synergy process could alter the secondary structure of protein, which caused a loose structure of EPS and the exposure of hydrophobic sites, facilitating the dehydration of sludge flocs. The details of how thermally-activated SPS process enhanced sludge dewaterability provided the theoretical and technical basis for the application of the process under a real-world situation.
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Affiliation(s)
- Shuyu Ruan
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Jing Deng
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China.
| | - Anhong Cai
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Shengnan Chen
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Yongqing Cheng
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Jun Li
- College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Qingsong Li
- Water Resources and Environmental Institute, Xiamen University of Technology, Xiamen, 361005, China
| | - Xueyan Li
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China
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Jessieleena AA, M P, Mp S. Comparative study of Fenton, Fe 2+/NaOCl and Fe 2+/(NH 4) 2S 2O 8 on tannery sludge dewaterability, degradability of organics and leachability of chromium. J Hazard Mater 2021; 402:123495. [PMID: 32739724 DOI: 10.1016/j.jhazmat.2020.123495] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 06/23/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
In this work, a comparative analysis of Fenton, Fe2+/NaOCl and Fe2+/(NH4)2S2O8 assisted advanced oxidation processes was carried out to study its efficacy in enhancing tannery chemical sludge dewaterability. Experimental results showed that, after conditioning of sludge at optimum pH, oxidant and catalyst dosage, capillary suction time (CST) was decreased by 75 ± 5 % and moisture content of sludge cake (M.Ccake) was reduced to 74 ± 2 % for all processes at 10 min reaction time. Among the three processes, Fe2+/(NH4)2S2O8 process was noted to have larger impact on the breakdown of sludge cells, which is reflected in terms of its highest amount of total organic carbon, protein and total dissolved solids present in the separated sludge fractions. In addition, Fe2+/(NH4)2S2O8 process was also observed to leach out largest fraction say 73.3 % of chromium present in the raw sludge into the treated sludge filtrate. The investigation carried out through zeta potential and scanning electron microscopy reveals the role of a two-step mechanism, namely oxidation followed by coagulation in enhancing the sludge dewaterability. Further studies on the possibility of utilizing dried treated sludge as biomass fuel could be carried out.
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Affiliation(s)
- A Angel Jessieleena
- Department of Environmental and Water Resources Engineering, School of Civil Engineering, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India.
| | - Priyanka M
- Department of Environmental and Water Resources Engineering, School of Civil Engineering, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India.
| | - Saravanakumar Mp
- Department of Environmental and Water Resources Engineering, School of Civil Engineering, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India.
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Rebosura M, Salehin S, Pikaar I, Keller J, Sharma K, Yuan Z. The impact of primary sedimentation on the use of iron-rich drinking water sludge on the urban wastewater system. J Hazard Mater 2021; 402:124051. [PMID: 33254834 DOI: 10.1016/j.jhazmat.2020.124051] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/07/2020] [Accepted: 09/19/2020] [Indexed: 06/12/2023]
Abstract
The impact of primary sedimentation on the multiple use of iron in an urban wastewater system was investigated. Our previous work showed that in-sewer iron-rich drinking water sludge (DWS) dosing exhibited multiple benefits in the downstream processes. However, the system studied did not include a primary settler. We hypothesised that primary sedimentation could significantly change the characteristics of the wastewater flowing to the bioreactor, particularly its particulate components. This could in turn influence the availability of iron for phosphate removal from wastewater and/or sulfide removal in the anaerobic sludge digester. Long-term (~4 months) experiments were carried out on two laboratory-scale wastewater systems, each comprising sewers reactors, a primary sedimentation tank, a wastewater treatment reactor, and an anaerobic sludge digester. It was found the majority (85%) of the Fe contained in the sewer effluent was present in the primary sludge with the remaining (15%) staying in the primary effluent. This significantly affected the flow-on effect of Fe on the phosphate removal during wastewater treatment, removing only 1.2 ± 0.1 mgP L-1, as compared to 3.5 ± 0.1 mgP L-1 achieved previously in the absence of a primary settler. However, the P to Fe removal ratio was 0.32 mgP/mgFe, similar to the ratio observed previously without primary sedimentation (0.36 mgP/mgFe). The dissolved sulfide removal in the anaerobic digester was 2.7 ± 0.5 mgS L-1, substantially lower than 7.2 ± 0.3 mgS L-1 previously attained without primary sedimentation. This suggests that Fe in the primary sludge was not completely available for dissolved sulfide removal in the digester. However, the dewaterability of the anaerobically digested sludge improved with a relative increase of 25.0 ± 0.9%, compared to the 21.7 ± 0.6%, previously observed without primary sedimentation. The results demonstrated that primary sedimentation reduced the effectiveness to deliver the benefits of the in-sewer DWS dosing strategy, but the results are still favourable.
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Affiliation(s)
- Mario Rebosura
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Sirajus Salehin
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia; The School of Civil Engineering, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Ilje Pikaar
- The School of Civil Engineering, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Jürg Keller
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Keshab Sharma
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
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Bian C, Ge D, Wang G, Dong Y, Li W, Zhu N, Yuan H. Enhancement of waste activated sludge dewaterability by ultrasound-activated persulfate oxidation: Operation condition, sludge properties, and mechanisms. Chemosphere 2021; 262:128385. [PMID: 33182129 DOI: 10.1016/j.chemosphere.2020.128385] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 08/24/2020] [Accepted: 09/16/2020] [Indexed: 06/11/2023]
Abstract
The study proposed the ultrasound-activated persulfate oxidation as a novel approach to enhance sludge dewaterability. The results demonstrated that the reduction of water content of dewatered sludge cake was 16.5% and the capillary suction time was reduced to 39.5 s at the optimal conditions of 1.0 mmol/g-TS S2O82- and ultrasound energy density of 2.0 kW L-1 within 15 min. The promotion of dewaterability was closely associated with the enlarged floc size, decreased viscosity, and near-neutral zeta potential. Meanwhile, the correlation analysis revealed that the protein in extracellular polymeric substances (EPS) governed sludge dewaterability, especially in loosely bound EPS. Three-dimensional excitation-emission matrix fluorescence spectroscopy, Fourier transform infrared spectroscopy and scanning electronic microscopy analysis revealed that ultrasound-activated persulfate oxidation treatment effectively degraded the gel-like EPS matrix and attacked cells, releasing the moisture which was trapped in EPS and cells. The aggregation of particles promoted the elimination of moisture. Furthermore, heavy metals in conditioned dewatered sludge cakes all satisfied the A level of agricultural land (GB4284-2018) requirements and the chemical speciation distribution of some heavy metals changed significantly.
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Affiliation(s)
- Chang Bian
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Dongdong Ge
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Guanjun Wang
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yanting Dong
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Wei Li
- College of Environmental & Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China
| | - Nanwen Zhu
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Haiping Yuan
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
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Hu Y, Kumar M, Wang Z, Zhan X, Stengel DB. Filamentous microalgae as an advantageous co-substrate for enhanced methane production and digestate dewaterability in anaerobic co-digestion of pig manure. Waste Manag 2021; 119:399-407. [PMID: 33191051 DOI: 10.1016/j.wasman.2020.10.041] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 10/07/2020] [Accepted: 10/27/2020] [Indexed: 05/16/2023]
Abstract
This study aimed at exploring filamentous microalgae (Tribonema sp.) as an advantageous co-substrate for anaerobic digestion (AD) of pig manure. Its impacts on the AD performance were assessed in terms of methane yield, energy conversion efficiency, digestion kinetics, and digestate dewaterability. The microalgae substantially improved methane yield, AD kinetics, and digestate dewaterability of the AD process. The enhancement in methane yield ranged from 2 to 27.4%, with the maximum enhancement (corresponding to an energy conversion efficiency of 81%) occurring at a mixing ratio of 1:1 (VS basis). The AD kinetics was improved as indicated by the increased hydrolysis rate constants and diminished lag time. The specific resistance to filtration (SRF) of the digestate decreased significantly with the increasing proportion of the microalgae in the co-substrates, which would facilitate digestate processing and valorisation. Subsequently, the high biomass productivity of the microalgae (441 mg/L/d) in liquid digestate would enable sustainable bioenergy production through nutrient recycling.
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Affiliation(s)
- Yuansheng Hu
- Civil Engineering, College of Engineering & Informatics, National University of Ireland, Galway, Ireland; Ryan Institute, National University of Ireland, Galway, Ireland
| | - Manoj Kumar
- Civil Engineering, College of Engineering & Informatics, National University of Ireland, Galway, Ireland
| | - Zhongzhong Wang
- Civil Engineering, College of Engineering & Informatics, National University of Ireland, Galway, Ireland
| | - Xinmin Zhan
- Civil Engineering, College of Engineering & Informatics, National University of Ireland, Galway, Ireland; Ryan Institute, National University of Ireland, Galway, Ireland; MaREI Research Centre, National University of Ireland, Galway, Ireland.
| | - Dagmar B Stengel
- Ryan Institute, National University of Ireland, Galway, Ireland; Botany and Plant Science, School of Natural Sciences, National University of Ireland, Galway, Ireland
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47
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Li Y, Xu Q, Liu X, Wang Y, Wang D, Yang G, Yuan X, Yang F, Huang J, Wu Z. Peroxide/Zero-valent iron (Fe 0) pretreatment for promoting dewaterability of anaerobically digested sludge: A mechanistic study. J Hazard Mater 2020; 400:123112. [PMID: 32947734 DOI: 10.1016/j.jhazmat.2020.123112] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 06/01/2020] [Accepted: 06/02/2020] [Indexed: 06/11/2023]
Abstract
Peroxide/Zero-valent iron (Fe0) was reported to promote dewaterability of anaerobically digested sludge (ADS), but the mechanism of how Peroxide/Fe0 facilitates ADS dewatering is unknown. This study therefore aims to uncover the details of how Peroxide/Fe° elevates ADS dewaterability. Experimental results showed that with 0.6 g Fe0/g TSS and 0.08 g peroxide/g TSS, capillary suction time, specific resistance to filtration, and time to filtration of ADS was 50.7 %, 41.4 %, and 54.4 % of that in the control, respectively. In this condition, water content of sludge cake decreased from 91.2 % ± 0.5 % (the control) to 68.6 % ± 1.3 %. The mechanism explorations revealed that the elevated dewaterability was mainly caused by role of OH and Fe(II)/Fe(III) species during Peroxide/Fe° pretreatment. OH decreased the polysaccharides and proteins in extracellular polymeric substance (EPS), then injured the cytoderm & cytomembrane through the releases of lactate dehydrogenase and N-acetylglucosamine, and further facilitated the decrease of intracellular substances, which disengaged the water trapped in ADS. In addition, the cell lysis caused by OH facilitated forming macro-pores. Moreover, OH converted the conformational structure of extracellular proteins, which may strengthen the ADS hydrophobicity, promoting the discharge of unbound water and ADS flocculation. Meanwhile, Fe(II)/Fe(III) benefited aggregating the denatured ADS particulates.
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Affiliation(s)
- Yifu Li
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China.
| | - Qiuxiang Xu
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China
| | - Xuran Liu
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China
| | - Yali Wang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China
| | - Dongbo Wang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China.
| | - Guojing Yang
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, PR China.
| | - Xingzhong Yuan
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China
| | - Fan Yang
- Hunan Communication Research Institute Co, Changsha, 410000, PR China
| | - Jin Huang
- Hunan Provincial Center for Ecological and Environmental Affairs, Changsha, 410000, PR China
| | - Zhibin Wu
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, PR China
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Wang X, Wang W, Zhou B, Xu M, Wu Z, Liang J, Zhou L. Improving solid-liquid separation performance of anaerobic digestate from food waste by thermally activated persulfate oxidation. J Hazard Mater 2020; 398:122989. [PMID: 32768831 DOI: 10.1016/j.jhazmat.2020.122989] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/02/2020] [Accepted: 05/15/2020] [Indexed: 06/11/2023]
Abstract
Anaerobic digestion is a promising ecofriendly technology for the management of the continuous increasing food waste (FW). However, the large amount of resulting anaerobic digestate are very difficult to be purified due to high concentration of suspended colloids. Solid-liquid separation is a pivotal step for the subsequent biological treatment of the digestate by activated sludge process. The dewaterability of digestate could directly reflect the solid-liquid separation performance. In this study, a thermally-activated persulfate (PDS) conditioning method was utilized to enhance the digestate dewaterability. Results revealed that PDS thermally conditioning significantly improved the dewaterability by decreasing digestate pH and decomposing organic substances in digestate. The decline of pH, which was resulted from PDS thermally activation reaction, facilitated filterability improvement via reducing the surface negative charges and prompting the oxidizing ability of PDS-relevant radicals. Protein, the main organic component in digestate, was most closely correlated with digestate dewaterability. Fortunately, they were also the most vulnerable constituent under the oxidation attack. PDS thermal conditioning at 80°C was proven to be the most suitable for improving the solid-liquid separation performance of anaerobic. For practical application in conditioning the anaerobic digestate from FW, the conditions should be further optimized according to the digestate characteristic.
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Affiliation(s)
- Xiaomeng Wang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Wei Wang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Bo Zhou
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Min Xu
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Zhenjiang Wu
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Jianru Liang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Lixiang Zhou
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China.
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49
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Guo Z, Ma L, Dai Q, Ao R, Liu H, Yang J. Combined application of modified corn-core powder and sludge-based biochar for sewage sludge pretreatment: Dewatering performance and dissipative particle dynamics simulation. Environ Pollut 2020; 265:115095. [PMID: 32806410 DOI: 10.1016/j.envpol.2020.115095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/22/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
Sludge is an inevitable by-product of municipal wastewater treatment processes, and its high moisture content poses a major challenge for its subsequent treatment and disposal. Previous studies have explored the effects of applying modified corn-core powder (MCCP) on dewatering sludge. Here, we characterized the effects of applying both MCCP and sludge-based biochar (SBB) on dewatering sludge. Analysis of the anti-shear ability of SBB revealed that SBB was a skeleton builder with high compressive strength, demonstrating that SBB could maintain the permeability of sludge under high-pressure filtration processes and facilitate the flow of bound water. Dissipative particle dynamics (DPD) was used to simulated the sludge flocculating process and verify the feasibility of the experiment. As the simulation progressed, the reaction in the sludge network reached equilibrium and the simulated structure of the sludge became loose. The dewatering performance and physicochemical properties of the treated sludge were studied to further characterize the effect of this combined technology. Compared with MCCP-sludge, MCCP&SBB-sludge, which was treated by 20% DS (mass of dry solids in sludge) of SBB and 20% DS of MCCP, achieved superior dewaterability. This combined method reduced the specific resistance of filtration by 76% and enlarged the net sludge solids yield by 138%. Further study of the properties of MCCP&SBB-sludge revealed a loose structure that resembled the structure recovered by the simulation, suggesting that the DPD simulation method simulated the sludge flocculating process successfully. Therefore, the combined application of MCCP and SBB was superior for sludge dewatering because of the synergistic effects of MCCP and SBB.
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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
| | - Jie Yang
- College of Resources and Environment, Chengdu University of Information Technology, Chengdu, 610225, Sichuan, China
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50
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Kim HJ, Chon K, Lee YG, Kim YK, Jang A. Enhanced mechanical deep dewatering of dewatered sludge by a thermal hydrolysis pre-treatment: Effects of temperature and retention time. Environ Res 2020; 188:109746. [PMID: 32540570 DOI: 10.1016/j.envres.2020.109746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 01/27/2020] [Accepted: 05/25/2020] [Indexed: 06/11/2023]
Abstract
This study investigated effects of the thermal hydrolysis pre-treatment on mechanical deep dewaterability of dewatered sludge to extend understanding of dewatering characteristics of thermally hydrolyzed sludge. Floc sizes of dewatered sludge were gradually reduced during the thermal hydrolysis pre-treatment at 170 °C and 185 °C with increasing retention time whereas longer retention time (>60 min) increased floc sizes of thermally hydrolyzed sludges at 200 °C due to formation of undesired refractory organic materials (ROMs), which might hinder the disintegration of dewatered sludge flocs. Similar trends were found for thermal hydrolytic solubilization of dewatered sludge. This demonstrated that the efficiency of the thermal hydrolysis pre-treatment at a higher temperature (200 °C) with longer retention time (≥60 min) could be strongly influenced by the formation of ROMs associated with changes of solid fractions and some free amino acids (i.e., β-aminobutyric acid, 4-hydroxyproline, and cysteine). Since the trade-off between the degradation of dewatered sludge and the formation of ROMs determined mechanical deep dewaterability of thermally hydrolyzed sludge, the lowest residual weight and moisture content were observed for thermally hydrolyzed sludges at 200 °C with retention time range of 60 min (residual weight = 0.165; moisture content = 55.38%) to 90 min (residual weight = 0.160; moisture content = 59.87%). These observations were intimately correlated to variations of extracellular polymeric substances during the thermal hydrolysis pre-treatment, but not in accordance with the change pattern of capillary suction time (CST) values. This is evident that the CST value was inadequate to estimate mechanical deep dewaterability of thermally hydrolyzed sludge.
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Affiliation(s)
- Hee-Joong Kim
- Hansu Technical Service Research Center, 145 Yatap-dong, Bundang-gu, Seongnam-si, Gyeonggi-do, Republic of Korea; Graduate School of Water Resources, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea
| | - Kangmin Chon
- Department of Environmental Engineering, College of Engineering, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon-si, Gangwon-do, Republic of Korea.
| | - Yong-Gu Lee
- Department of Environmental Engineering, College of Engineering, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon-si, Gangwon-do, Republic of Korea
| | - Youn-Kwon Kim
- K-water Institute, Yuseong-daero, 1689 Beon-gil, Yuseong-gu, Daejeon, Republic of Korea
| | - Am Jang
- Graduate School of Water Resources, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea.
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