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Yang N, Yang S. Neglected sludge solid phase in sludge pretreatment process: Physicochemical characterization and mechanism study of its role in anaerobic degradation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 944:173769. [PMID: 38848921 DOI: 10.1016/j.scitotenv.2024.173769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 06/01/2024] [Accepted: 06/02/2024] [Indexed: 06/09/2024]
Abstract
The low anaerobic digestion efficiency of the solid phase separated from pre-treated sludge indicates the need to explore other suitable resource utilization pathways for sludge solid phase. However, there is a lack of comprehensive and in-depth research on the physicochemical properties of sludge solid phase. This study comprehensively analyzes the characteristics of sludge solid phase and elucidates the mechanism of sludge solid phase in the anaerobic degradation of toxic wastewater. The results show that the surface free energy of sludge solid phase after different pre-treatments is mainly contributed by Lewis acid-base hydration free energy. The distribution of proteins on the surface of sludge solid phase plays a major role in the adhesion between sludge solid particles. Metal ions in the sludge solid phase are mainly present in the exchange state, followed by the carbonate state and the organics-bound state. The sludge solid phase obtained by sludge pH 12 + 150 °C treatment has the highest conductivity (1.36 mS/m) and capacitance (25.51 μF/g), mainly due to the presence of melanoidins in the sludge solid phase, which has similar semiquinone radicals to humic acids, thus increasing conductivity. The addition of sludge solid phase promotes an increase in cumulative methane production and rate of methane production. The sludge solid phase might play a role of an auxiliary carbon source acting as an adsorbent to buffer against toxicity inhibition and facilitate electron transfer. This study reveals the characteristics of sludge solid phase and its role in anaerobic digestion, providing theoretical guidance for finding suitable resource utilization pathways for sludge solid phase.
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Affiliation(s)
- Ning Yang
- Department of Environmental Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Shucheng Yang
- Department of Environmental Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
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2
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Wu Y, Liu Y, Zhang X, Gao M, Zhang C, Zang X, Wu L. Feasibility of sludge deep dewaterability improvement for incineration disposal by combined conditioning of freeze-thaw and sawdust. ENVIRONMENTAL RESEARCH 2024; 252:118987. [PMID: 38670212 DOI: 10.1016/j.envres.2024.118987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/22/2024] [Accepted: 04/21/2024] [Indexed: 04/28/2024]
Abstract
Sludge incineration is the main strategy for sludge reduction in China. The combined conditioning of lime and chemical agents has been proven to achieve sludge dewatering by disrupting the extracellular polymeric substances (EPS) of sludge and reducing its compressibility. However, when incineration is the intended disposal purpose, this method poses challenges such as incomplete combustion, equipment corrosion, secondary pollution, and decreased calorific value of sludge cake. In contrast, freeze-thaw conditioning, coupled with sawdust as a high-calorific-value bio-waste, emerges as an efficient and clean alternative. The research investigates the synergistic effects of freeze-thaw and sawdust co-conditioning on various sludge properties, including dewaterability, compressibility, consolidation, permeability, microscopicity, and calorific value. The study reveals that the combined conditioning significantly reduces water content and compressibility while increasing void ratio, consolidation, permeability, and enhancing the calorific value of the sludge cake. Specifically, sludge cake conditioned with 60% dried solids (DS) sawdust and freeze-thaw achieved a water content (Wc) of 49.07% and a calorific value of 1422.3 kcal/kg, meeting standards for self-sustained incineration. With heat recovery, the combined conditioning generates an economic revenue of 25.1 $/t DS after deducting costs, thereby reducing the overall cost of sludge reduction treatment. This research offers a clean and practical solution for sludge incineration and reduction, demonstrating great economic value and application potential.
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Affiliation(s)
- Yajun Wu
- Department of Civil Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China.
| | - Yang Liu
- Department of Civil Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China.
| | - Xudong Zhang
- Department of Civil Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China.
| | - Mengze Gao
- Department of Civil Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China
| | - Changsong Zhang
- Shanghai Yaxin Urban Construction Co., Ltd., Shanghai, PR China
| | - Xueke Zang
- Shanghai Yaxin Urban Construction Co., Ltd., Shanghai, PR China
| | - Linbao Wu
- Department of Civil Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China
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3
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Chen X, Liang S, Tao S, Yu W, Yuan S, Jian S, Wan N, Zhu Y, Bian S, Liu Y, Huang L, Duan H, Awasthi MK, Yang J. Sludge-derived iron-carbon material enhancing the removal of refractory organics in landfill leachate: Characteristics optimization, removal mechanism, and molecular-level investigation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166883. [PMID: 37690764 DOI: 10.1016/j.scitotenv.2023.166883] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/01/2023] [Accepted: 09/04/2023] [Indexed: 09/12/2023]
Abstract
Mature landfill leachate is a refractory organic wastewater, and needs physical and chemical pretreatments contemporaneously, e.g. iron-carbon micro-electrolysis (IC-ME). In this study, a novel iron-carbon (Fe-C) material was synthesized from waste activated sludge to be utilized in IC-ME for landfill leachate treatment. The pyrolysis temperature, mass ratio of iron to carbon, and solid-liquid ratio in leachate treatment were optimized as 900 °C with 1.59 and 34.7 g/L. Under these optimal conditions, the chemical oxygen demand (COD) removal efficiency reached 79.44 %, which was 2.6 times higher than that of commercial Fe-C material (30.1%). This excellent COD removal performance was indicated to a better mesoporous structure, and uniform distribution of zero-valent iron in novel Fe-C material derived from sludge. The contribution order of COD removal in IC-ME treatment for landfill leachate was proven as coagulation, adsorption, and redox effects by a contrast experiment. The removal of COD includes synthetic organic compounds, e.g. carcinogens, pharmaceuticals and personal care products. The contents of CHO, CHON, and CHOS compounds of dissolved organic matter (DOM) in the leachate were decreased, and both the molecular weight and unsaturation of lipids, lignin, and tannic acids concentration were also reduced. Some newly generated small molecular DOM in the treated leachate further confirmed the existence of the redox effect to degrade DOM in leachate. The total cost of sludge-derived Fe-C material was only USD$ 152.8/t, which could save 76% of total compared with that of commercial Fe-C materials. This study expands the prominent source of Fe-C materials with excellent performance, and deepens the understanding of its application for leachate treatment.
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Affiliation(s)
- Xinyue Chen
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Sha Liang
- School of Environmental Science & 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; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China
| | - Shuangyi Tao
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Wenbo Yu
- School of Environmental Science & 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; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China.
| | - Shushan Yuan
- School of Environmental Science & 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; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China
| | - Sifeng Jian
- Central & Southern China Municipal Engineering Design and Research Institute Co., Ltd., Wuhan, Hubei 430010, China
| | - Nianhong Wan
- Central & Southern China Municipal Engineering Design and Research Institute Co., Ltd., Wuhan, Hubei 430010, China
| | - Yuwei Zhu
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Shijie Bian
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yuan Liu
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Liang Huang
- School of Environmental Science & 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; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China
| | - Huabo Duan
- School of Environmental Science & 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; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China
| | - Mukesh Kumar Awasthi
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jiakuan Yang
- School of Environmental Science & 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; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China
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4
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Yuan X, Cui K, Chen Y, Zhang Y, Wu S, Xie X, Liu T, Yao H. Microbial community and gene dynamics response to high concentrations of gadolinium and sulfamethoxazole in biological nitrogen removal system. CHEMOSPHERE 2023; 342:140218. [PMID: 37734503 DOI: 10.1016/j.chemosphere.2023.140218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/16/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023]
Abstract
The impact of high antibiotic and heavy metal pollution levels on biological nitrogen removal in wastewater treatment plants (WWTPs) remains poorly understood, posing a global concern regarding the issue spread of antibiotic resistance induced by these contaminants. Herein, we investigated the effects of gadolinium (Gd) and sulfamethoxazole (SMX), commonly found in medical wastewater, on biological nitrogen removal systems and microbial characteristics, and the fate of antibiotic resistance genes (ARGs), metal resistance genes (MRGs), and mobile genetic elements (MGEs). Our findings indicated that high SMX and Gd(III) concentrations adversely affected nitrification and denitrification, with Gd(III) exerting a strong inhibitory effect on microbial activity. Metagenomic analysis revealed that high SMX and Gd(III) concentrations could reduce microbial diversity, with Thauera and Pseudomonas emerging as dominant genera across all samples. While the relative abundance of most ARGs decreased under single Gd(III) stress, MRGs increased, and nitrification functional genes were inhibited. Conversely, combined SMX and Gd(III) pollution increased the relative abundance of intl1. Correlation analysis revealed that most genera could host ARGs and MRGs, indicating co-selection and competition between these resistance genes. However, most denitrifying functional genes exhibited a positive correlation with MRGs. Overall, our study provides novel insights into the impact of high concentrations of antibiotics and heavy metal pollution in WWTPs, and laying the groundwork for the spread and proliferation of resistance genes under combined SMX and Gd pollution.
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Affiliation(s)
- Xinrui Yuan
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Kangping Cui
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China.
| | - Yihan Chen
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yao Zhang
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Shiyang Wu
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Xianjin Xie
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Tong Liu
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Hongjia Yao
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
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5
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Bi W, Chen M, Hu C, Sun H, Xu S, Jiang J, Wang L, Li X, Deng J. Insight into sludge dewatering by periodate driven directly with Fe(Ⅱ): Extracellular polymeric substances solubilization and mineralization. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 344:118450. [PMID: 37413734 DOI: 10.1016/j.jenvman.2023.118450] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/25/2023] [Accepted: 06/16/2023] [Indexed: 07/08/2023]
Abstract
The production of waste activated sludge is expanding in tandem with the significant growth in the global population. It is important to explore sludge pretreatment technology to achieve sludge reduction. In this study, deep sludge dewatering was achieved by using Fe2+-catalyzed periodate (Fe2+/PI) conditioning. The result showed that capillary suction time was reduced by 48.27% under the optimum Fe2+ and PI dosages. ·OH, FeⅣ, O2·-, 1O2, and IO3· generated from the reaction between Fe2+ and PI, while ·OH (49.79%) and FeⅣ (47.76%) contributed significantly to sludge dewatering. Investigations of the mechanism revealed that the synergistic action of radical species oxidation and iron species flocculation in Fe2+/PI conditioning led to the mineralization and aggregation of hydrophilic substances in extracellular polymeric substances. The hydrophobic groups on the protein surface were more exposed to soluble extracellular polymeric substances and reduced protein-water interaction. The variations in zeta potential and particle size also verified the presence of a synergistic effect of oxidation and flocculation. The morphology observations revealed that the increased frictional forces generated when water flowed over the raw sludge (RS) surface prevented the rapid passage of internal water. In addition, the hydrophobic and electrostatic interactions in the sludge samples were essential influences that promoted flocculation and sedimentation of the sludge. This research aids engineers by providing a new option to better optimize sludge management while also deepening understanding of the Fe2+/PI conditioning involved in sludge dewatering.
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Affiliation(s)
- Weiwei Bi
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China; Zhejiang Key Laboratory of Civil Engineering Structures & Disaster Prevention and Mitigation Technology, Hangzhou, 310023, China
| | - Minjie Chen
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Chenkai Hu
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Honglei Sun
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China; Zhejiang Key Laboratory of Civil Engineering Structures & Disaster Prevention and Mitigation Technology, Hangzhou, 310023, China
| | - Shanlin Xu
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China; Zhejiang Key Laboratory of Civil Engineering Structures & Disaster Prevention and Mitigation Technology, Hangzhou, 310023, China
| | - Jiahong Jiang
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Lei Wang
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Xueyan Li
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China
| | - Jing Deng
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310023, China; Zhejiang Key Laboratory of Civil Engineering Structures & Disaster Prevention and Mitigation Technology, Hangzhou, 310023, China.
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6
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Wu B, Li H, Zhou K, Yu N, Xu Q, Chai X, Dai X. Crystallization-driven evolution of water occurrence states with implications on dewaterability improvement of waste-activated sludge. WATER RESEARCH 2023; 244:120496. [PMID: 37633208 DOI: 10.1016/j.watres.2023.120496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/25/2023] [Accepted: 08/16/2023] [Indexed: 08/28/2023]
Abstract
This study proposed to improve the dewaterability of waste-activated sludge (WAS) through crystallization-driven evolution of water occurrence states. Primarily, the feasibility of clathrate hydrate (i.e., CO2 hydrate) formation in WAS was examined. The thermodynamic analysis indicated that the CO2 hydrate formation with the excessive water in WAS followed pseudo-first-order kinetics, and fit of the data yielded a kobs value of 3.905 × 10-5 L∙mol-1∙s-1 for 274.15 K. With the water conversion efficiency of 100%, the crystallization-dissociation process of CO2 hydrate significantly improved the dewaterability of WAS in term of capillary suction time (CST) decreasing from 251.5 s to 57.4 s. Also, the relief of gas pressure can induce the hydrate dissociation, which creates a novel way to recycle CO2 gas and save the consumption of chemicals required by sludge dewatering process. Regarding the mechanism of hydrates-based sludge dewatering, the evolution of water occurrence state was investigated. The in-situ synchrotron X-ray computed microtomography visually analyzed the micro-scale porosity and interstitial water of WAS flocs. The model of three-dimensional pore structure was established and the porosity parameters of solid aggregates were determined. It was found that the volume of connected pores and the total pore volume fraction of solid compositions increased. But the mean volume and mean area of isolated pores simultaneously decreased by 14.6% and 12.4%, respectively, which meant that the steric hindrance caused by isolated pores was weakened due to the reduced solid-water contact area. In addition, the crystallization of water caused the reformation of conformation arrangement of vicinal water and solid molecules, which highly organized the water molecules into the crystal structure. Accordingly, an estimation method for vicinal water layer thickness was developed based on atom force microscope. The thickness of vicinal water layer was found to be reduced by 77.4% and the hydration repulsion among solid compositions was correspondingly weakened, which facilitated the aggregation of solid compositions, and the relatively separated hydrate phase and solid phase could be formed. All the above results open up a novel strategy for enhanced water-solid separation of WAS through the crystallization-driven evolution of water occurrence states. As distinguished from the conventional approaches, the hydrates-based sludge dewatering enhances the water-solid separation only with regulating the spatial arrangement of water-solid molecules, but without altering the chemical compositions. Thus, more chances can be created to increase the environmentally friendly attributes related to WAS dewatering.
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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; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Hewei Li
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Kun Zhou
- Shanghai Municipal Engineering Design Institute (Group) Co., Ltd., 901 Zhongshan North 2nd Road, Shanghai 200092, China
| | - Ningrui Yu
- Shanghai Guohui Environmental Technology Co., Ltd., 169-39, Gaoguang Road, Shanghai 201702, China
| | - Qinqin Xu
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, 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.
| | - 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.
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Ward BJ, Nguyen MT, Sam SB, Korir N, Niwagaba CB, Morgenroth E, Strande L. Particle size as a driver of dewatering performance and its relationship to stabilization in fecal sludge. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 326:116801. [PMID: 36435127 DOI: 10.1016/j.jenvman.2022.116801] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/03/2022] [Accepted: 11/13/2022] [Indexed: 06/16/2023]
Abstract
Poor and unpredictable dewatering performance of fecal sludge is a major barrier to sanitation provision in urban areas not served by sewers. Fecal sludge comprises everything that accumulates in onsite containments, and its characteristics are distinct from wastewater sludges and from feces. There is little fundamental understanding of what causes poor dewatering in fecal sludge. For the first time, we demonstrate that particle size distribution is a driver of dewatering performance in fecal sludge, and is associated with level of stabilization. Higher concentrations of small particles (<10 μm) and smaller median aggregate size (D50) corresponded to poor dewatering performance (measured by capillary suction time (CST) and supernatant turbidity) in field samples from Kenya and Uganda and in controlled laboratory anaerobic storage experiments. More stabilized fecal sludge (higher C/N, lower VSS/TSS) had better dewatering performance, corresponding to lower concentrations of small particles. Samples with the largest aggregates (D50 > 90 μm) had higher abundance of Gammaproteobacteria Pseudomonas, and samples with the smallest aggregates (D50 ≤ 50 μm) were characterized by higher abundance of Bacteroidetes Vadin HA17 and Rikenellaceae. Contrary to common perceptions, stabilization, particle size distribution, and dewatering performance were not dependent on time intervals between emptying of onsite containments or on time in controlled anaerobic storage experiments. Our results suggest that the stabilization process in onsite containments, and hence the dewaterability of sludge arriving at treatment facilities, is not dependent on time in containment but is more likely associated with specific microbial populations and the in-situ environmental conditions which promote or discourage their growth.
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Affiliation(s)
- B J Ward
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, Zürich, Switzerland.
| | - M T Nguyen
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, Zürich, Switzerland
| | - S B Sam
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, Zürich, Switzerland
| | | | - C B Niwagaba
- Makerere University, Department of Civil and Environmental Engineering, Kampala, Uganda
| | - E Morgenroth
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, Zürich, Switzerland
| | - L Strande
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
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8
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Ling X, Cai A, Chen M, Sun H, Xu S, Huang Z, Li X, Deng J. A comparison of oxidation and re-flocculation behaviors of Fe 2+/PAA and Fe 2+/H 2O 2 treatments for enhancing sludge dewatering: A mechanism study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 847:157690. [PMID: 35905956 DOI: 10.1016/j.scitotenv.2022.157690] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/24/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
In this study, Fe2+ activated-PAA was developed as a novel technology to enhance sludge dewatering. The result showed that the filterability (CST0/CST) enhanced by 4.20 ± 0.14 times more than the control, and the SRF and bound water content decreased from 4.58 ± 0.07 × 1013 m/kg and 2.11 ± 0.28 g/g dry sludge to 9.47 ± 0.05 × 1012 m/kg and 1.27 ± 0.18 g/g dry sludge, respectively after the sludge was conditioned by 1.20 mM/g VSS Fe2+ and 1.20 mM/g VSS PAA. The dewatering performance, physicochemical properties, aggregation behaviors, and EPS fractions of sludge were compared before and after Fe2+/PAA and Fe2+/H2O2 conditionings. The results showed that Fe2+/PAA treatment was more competitive in enhancing dewaterability under neutral and alkaline conditions than Fe2+/H2O2 treatment but slightly weaker under acid conditions. Besides, it was found that the oxidation and re-flocculation behaviors were different in those two enhanced dewatering technologies due to the difference in the generated ROS. R-O was the primary radical in the Fe2+/PAA system, while OH was the major one in the Fe2+/H2O2 system. The mechanism analysis found that the Fe2+/PAA process caused harsher disintegration of sludge flocs, meaning more generation of fine particles. However, it exhibited less effect on reducing the energy barrier between sludge particles. Therefore, the Fe2+/PAA treated sludge presented weaker aggregation behaviors. The weaker aggregation was unfavorable for sludge dewatering because the weaker aggregated flocs were more easily fragmented, which hampered the consolidation of sludge cakes and removal of bound water. Moreover, loosely-bound extracellular polymeric substances, particularly tightly-bound extracellular polymeric substances, governed the sludge dewaterability.
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Affiliation(s)
- Xiao Ling
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Anhong Cai
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Minjie Chen
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Honglei Sun
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Shanlin Xu
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Zhiyuan Huang
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Xueyan Li
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Jing Deng
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China.
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9
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Chen K, Sun Y, Fan J, Gu Y. The dewatering performance and cracking-flocculation-skeleton mechanism of bioleaching-coal fly ash combined process for sewage sludge. CHEMOSPHERE 2022; 307:135994. [PMID: 35973485 DOI: 10.1016/j.chemosphere.2022.135994] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 07/27/2022] [Accepted: 08/07/2022] [Indexed: 06/15/2023]
Abstract
High water content in sludge will affect the transportation and subsequent disposal of sludge. Bioleaching is a biological sludge conditioning technology, which can effectively improve the dewatering performance of sludge and reduce the content of heavy metals in sludge. Coal fly ash, as a skeleton builder, can also improve the dewatering performance of sludge. In this study, bioleaching combined with coal fly ash (BL-CFA) process was employed to improve sludge dewatering performance. Based on the results of response surface methodology (RSM), the capillary suction time (CST) and water content (WC) of sludge decreased by 52.27% and 38.92%, respectively. The dewatering effect of BL-CFA is superior compared with single process. For extracellular polymeric substances (EPS), the content of protein and polysaccharide in tightly and loosely EPS (TB-EPS and LB-EPS) of sludge decreased after BL-CFA process, while that in soluble EPS (S-EPS) increased. Three-dimensional fluorescence indicated that the weakened fluorescent areas of proteinoid and soluble microbial by-product-like (SMP) organic in LB-EPS and TB-EPS, which is beneficial to the improvement of sludge dewatering performance. Fourier transform infrared (FTIR) spectroscopy showed that the polysaccharides and proteins in the sludge were cleaved and released into the supernatant after BL-CFA process. The variation of particle size revealed that flocculation occurred after adding CFA into acidified sludge, and a supporting structure was formed in the sludge with the assist of CFA through the analysis of the scanning electron microscopy (SEM). Based on the above results, a triple dehydration mechanism was proposed for BL-CFA process, namely, cracking-flocculation-skeleton construction, which endows the combined process with superior sludge dewatering effect and application potential.
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Affiliation(s)
- Kai Chen
- School of Civil Engineering, Southeast University, Nanjing, 210096, China
| | - Yue Sun
- School of Civil Engineering, Southeast University, Nanjing, 210096, China.
| | - Jun Fan
- Nanjing Huachuang Environmental Technology Research Institute Co., Ltd, Nanjing, 210096, China
| | - YingPeng Gu
- School of Civil Engineering, Southeast University, Nanjing, 210096, China
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10
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Lv H, Liu Y, Wu X, Lv R, Zhou X, Ma X, Xiong Q. A closed-loop electrokinetic system for recovery of PbO 2@Fe composite derived from lead-containing sludge. CHEMOSPHERE 2022; 304:135338. [PMID: 35709836 DOI: 10.1016/j.chemosphere.2022.135338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/10/2022] [Accepted: 06/11/2022] [Indexed: 06/15/2023]
Abstract
Lead-containing sludge produced from lead-acid battery factory will cause environmental hazards if they are not treated properly. A novel process was developed to recycle lead from sludge back into Fe-doped PbO2 electrodes and realize sludge reduction in this study. The effects of Fenton conditioning on Pb removal efficiency in electro-kinetic (EK) treatment process and its mechanism as well as electro-dewatering (ED) performance were investigated. It was found that the oxidation of Fenton can promote desorption and release of Pb from the organic binding state, and improve the removal efficiency of Pb during EK process, as well as enhance sludge ED performance. About 63.8 wt% Pb can be removed from sludge during EK process, achieving sludge reduction of 63.5 wt% by ED treatment. The composite PbO2@Fe electrode recovered from lead-containing sludge showed a high electrocatalytic activity for acid red G (ARG) degradation. The electrode obtained by electrodeposition at 20 mA cm-2 had the largest exchange current density (3.26 × 10-5 A cm-2). In the experiment of dye wastewater electrocatalytic degradation, over 99.5% organic matter was degraded within 80 min.
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Affiliation(s)
- Hang Lv
- Hubei Engineering University, Wuhan, Hubei, 432000, China; School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China
| | - Yao Liu
- College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan, Hubei, 430065, China
| | - Xu Wu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China
| | - Ruibing Lv
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China
| | - Xiangjun Zhou
- College of Urban and Environmental Sciences, Hubei Normal University, Huangshi, Hubei, 435002, China
| | - Xiao Ma
- College of Urban and Environmental Sciences, Hubei Normal University, Huangshi, Hubei, 435002, China
| | - Qiao Xiong
- College of Urban and Environmental Sciences, Hubei Normal University, Huangshi, Hubei, 435002, China.
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11
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Zhang Q, Cui G, He X, Wang Z, Tang T, Zhao Q, Liu Y. Effects of voltage and pressure on sludge electro-dewatering process and the dewatering mechanisms investigation. ENVIRONMENTAL RESEARCH 2022; 212:113490. [PMID: 35594958 DOI: 10.1016/j.envres.2022.113490] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/31/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
Electro-dewatering technology shows a good application prospect because of its high efficiency in removing water from sludge and low energy consumption, but the potential mechanisms of sludge electro-dewatering have not been investigated in depth, which seriously limits the further development and application of electro-dewatering technology. In this study, the effects of voltage and pressure on sludge electro-dewatering performance, physicochemical characteristics and extracellular polymeric substances (EPS) compositions and distributions were investigated. The spatial distributions of EPS main components, including polysaccharide (PS) and protein (PN), were characterized by a confocal laser scanning microscopy (CLSM). The experimental results showed that under the conditions of a voltage of 40 V and a pressure of 90 kPa, the moisture content of sludge was reduced from 83.15% to 53.12%, and the bound water content of sludge in the anode layer, middle layer and cathode layer were decreased significantly from 1.16 g/g dry solid (DS) to 0.20, 0.47 and 0.35 g/g DS, respectively. The PN content of EPS in anode layer was significantly lower than that in cathode layer due to the electrochemical oxidation, while the variation of PS content showed the opposite trend, which agreed with the results visualized by CLSM. Pearson's correlation coefficient and hierarchical cluster analysis revealed that PN in TB-EPS was the major factor influencing the effect of sludge electro-dewatering. This work can be helpful to understand the potential mechanisms of electro-dewatering and provide theoretical support for the further popularization and application of electro-dewatering technology.
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Affiliation(s)
- Qiming Zhang
- College of Environmental Sciences and Engineering, Peking University, Beijing Key Laboratory for Solid Waste Utilization and Management, Beijing, 100871, China
| | - Guodong Cui
- College of Environmental Sciences and Engineering, Peking University, Beijing Key Laboratory for Solid Waste Utilization and Management, Beijing, 100871, China
| | - Xiao He
- College of Environmental Sciences and Engineering, Peking University, Beijing Key Laboratory for Solid Waste Utilization and Management, Beijing, 100871, China
| | - Zheng Wang
- College of Environmental Sciences and Engineering, Peking University, Beijing Key Laboratory for Solid Waste Utilization and Management, Beijing, 100871, China
| | - Tian Tang
- College of Environmental Sciences and Engineering, Peking University, Beijing Key Laboratory for Solid Waste Utilization and Management, Beijing, 100871, China
| | - Qing Zhao
- State Key Laboratory of Heavy Oil Processing, College of Science, China University of Petroleum, Beijing, 102249, China
| | - Yangsheng Liu
- College of Environmental Sciences and Engineering, Peking University, Beijing Key Laboratory for Solid Waste Utilization and Management, Beijing, 100871, China.
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12
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Raksasat R, Abdelfattah EA, Liew CS, Rawindran H, Kiatkittipong K, Mohamad M, Mohd Zaid HF, Jumbri K, Lam MK, Lim JW. Enriched sewage sludge from anaerobic pre-treatment in spurring valorization potential of black soldier fly larvae. ENVIRONMENTAL RESEARCH 2022; 212:113447. [PMID: 35561830 DOI: 10.1016/j.envres.2022.113447] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/26/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
The valorization of sewage sludge by black soldier fly larvae (BSFL) has gained attentions for sewage sludge management since the sludge can be reduced securely as well as larval biomass can be used for biorefineries application. Nevertheless, the BSFL growth was impeded while assimilating nutrition from sewage sludge due to the presence of extracellular polymeric substances (EPS) that had entrapped the essential nutrients inside. Accordingly, the pre-treatment of sewage sludge via anaerobic digestion at different pH was employed in this work to rupture the EPS structure and release more nutrients for larval growth. The results showed that larvae fed with raw sewage sludge had attained the lowest final larval weight (2.05 ± 0.38 mg/larva) as opposed to batches fed with pre-treated sewage sludges. This was because the soluble carbohydrate (more than 6.81 ± 1.31 mg of glucose/g sewage sludge) in EPS was released after anaerobic pre-treatment, facilitating larval assimilation for growth. Furthermore, it was observed that further increasing of pH for sewage sludge pre-treatment had led to lower final larval weight gained due to the inhibitory effect stemming from ammonia production at higher pH. The anaerobic pre-treatment of sewage sludge being executed at pH 3 for 8 days had achieved the highest final larval weight at 7.34 ± 0.97 mg/larva. The still low quality of sewage sludges after the pre-treatment also offered benefit, where high sewage sludge reduction and waste reduction index were recorded due to the necessity of BSFL to consume more sewage sludge in compensating the nutrients destitution in sludge. Lastly, the possibility of predicting final larval weight was successfully materialized via a statistical model derived from the multiple linear regression method. The derived model incorporated the interactive parameters of anaerobic pre-treated pH and durations at various combinations could predict the final larval weight.
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Affiliation(s)
- Ratchaprapa Raksasat
- Department of Fundamental and Applied Sciences, HICoE-Centre for Biofuel and Biochemical Research, Institute of Self-Sustainable Building, Universiti Teknologi PETRONAS, 32610, Seri Iskandar, Perak Darul Ridzuan, Malaysia
| | | | - Chin Seng Liew
- Department of Fundamental and Applied Sciences, HICoE-Centre for Biofuel and Biochemical Research, Institute of Self-Sustainable Building, Universiti Teknologi PETRONAS, 32610, Seri Iskandar, Perak Darul Ridzuan, Malaysia
| | - Hemamalini Rawindran
- Department of Fundamental and Applied Sciences, HICoE-Centre for Biofuel and Biochemical Research, Institute of Self-Sustainable Building, Universiti Teknologi PETRONAS, 32610, Seri Iskandar, Perak Darul Ridzuan, Malaysia
| | - Kunlanan Kiatkittipong
- Department of Chemical Engineering, School of Engineering, King Mongkut's Institute of Technology Ladkrabang, Bangkok, 10520, Thailand.
| | - Mardawani Mohamad
- Faculty of Bioengineering and Technology, Universiti Malaysia Kelantan, Jeli Campus, 17600, Jeli, Kelantan, Malaysia
| | - Hayyiratul Fatimah Mohd Zaid
- Department of Chemical Engineering, Centre of Innovative Nanostructures & Nanodevices (COINN), Institute of Autonomous System, Universiti Teknologi PETRONAS, 32610, Seri Iskandar, Perak Darul Ridzuan, Malaysia
| | - Khairulazhar Jumbri
- Department of Fundamental and Applied Sciences, Centre of Research in Ionic Liquids (CORIL), Institute of Contaminant Management, Universiti Teknologi PETRONAS, 32610, Seri Iskandar, Perak Darul Ridzuan, Malaysia
| | - Man Kee Lam
- Department of Chemical Engineering, HICoE-Centre for Biofuel and Biochemical Research, Institute of Self-Sustainable Building, Universiti Teknologi PETRONAS, 32610, Seri Iskandar, Perak Darul Ridzuan, Malaysia
| | - Jun Wei Lim
- Department of Fundamental and Applied Sciences, HICoE-Centre for Biofuel and Biochemical Research, Institute of Self-Sustainable Building, Universiti Teknologi PETRONAS, 32610, Seri Iskandar, Perak Darul Ridzuan, Malaysia.
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13
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Li H, Chen J, Zhang J, Dai T, Yi H, Chen F, Zhou M, Hou H. Multiple environmental risk assessments of heavy metals and optimization of sludge dewatering: Red mud-reed straw biochar combined with Fe 2+ activated H 2O 2. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 316:115210. [PMID: 35550958 DOI: 10.1016/j.jenvman.2022.115210] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/22/2022] [Accepted: 04/30/2022] [Indexed: 06/15/2023]
Abstract
In this study, Fe-rich biochar (RMRS-BC) was prepared from red mud and reed straw to improve sludge dewatering and transformation of heavy metals (HMs, including Cd, Cr, Cu, Pb, and Zn). The optimal concentrations of RMRS-BC, Fe2+, and H2O2 to promote sludge dewaterability were identified by response surface methodology (RSM). The optimal dosages of RMRS-BC, Fe2+, and H2O2 were 74.0, 104.9, and 75.7 mg/g dry solids (DS), respectively. The corresponding capillary suction time (CST) and water content of sludge cake were 14.3 s and 51.25 wt%. For the improvement mechanism, heterogeneous and homogeneous Fenton reactions occurred due to RMRS-BC and Fe2+ activating H2O2. The extracellular polymeric substances (EPS) decomposed into dissolved organic matter (proteins and polysaccharides), thereby promoting the transformation of bound water to free water and further reducing the water content of the sludge cake. The research quantitatively assessed the environmental risk of heavy metals in the conditioned sludge cake based on bioavailability and ecotoxicity, pollution levels and potential ecological risks. Compound conditioning using RMRS-BC, Fe2+, and H2O2 could significantly improve the solubility and reduce the leaching toxicity of HMs. In general, RMRS-BC combined with Fe2+ to activate H2O2 provided an effective method to enhance sludge dewaterability and reduce HMs risk.
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Affiliation(s)
- He Li
- School of Resource and Environmental Science, Wuhan University, Wuhan, 430072, Hubei, China
| | - Jiaao Chen
- School of Resource and Environmental Science, Wuhan University, Wuhan, 430072, Hubei, China
| | - Jiaxing Zhang
- School of Resource and Environmental Science, Wuhan University, Wuhan, 430072, Hubei, China
| | - Tenglong Dai
- School of Resource and Environmental Science, Wuhan University, Wuhan, 430072, Hubei, China
| | - Han Yi
- School of Resource and Environmental Science, Wuhan University, Wuhan, 430072, Hubei, China; College of Resources and Environment, Anqing Normal University, Anqing, 246011, Anhui, China
| | - Fangyuan Chen
- School of Resource and Environmental Science, Wuhan University, Wuhan, 430072, Hubei, China
| | - Min Zhou
- School of Resource and Environmental Science, Wuhan University, Wuhan, 430072, Hubei, China
| | - Haobo Hou
- School of Resource and Environmental Science, Wuhan University, Wuhan, 430072, Hubei, China.
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14
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Liang J, Zhou Y. Iron-based advanced oxidation processes for enhancing sludge dewaterability: State of the art, challenges, and sludge reuse. WATER RESEARCH 2022; 218:118499. [PMID: 35537253 DOI: 10.1016/j.watres.2022.118499] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 04/12/2022] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
The increasing amount of sewage sludge produced in wastewater treatment plants (WWTPs) poses a great challenge to both environment and economy globally. As a requisite process during sludge treatment, sludge dewatering can significantly minimize the sludge volume and lower the operational cost for downstream transportation and disposal. Iron-based advanced oxidation process (AOP), a robust and cost-effective technique with relatively low technical barriers for high-level sludge dewatering, has been widely explored in the past 20 years. The development was mainly driven by the demands of efficient and sustainable sludge conditioning technology and the flexible sludge management approaches. The application of iron-based AOPs in sludge dewatering process attracts more and more attention. In this work, we discussed the current application of iron-based AOPs technology in the sludge dewatering processes in a holistic manner, summarized the factors affecting the sludge dewaterability in the treatment processes, and analyzed the mechanisms of iron-based AOPs to improve dewatering processes. Furthermore, we elaborated potential advantages, limitations, and challenges associated with implementing iron-based AOPs in the full-scale plants and shared the opportunities for sludge reutilization. This review aims to contribute to the development of highly efficient iron-based AOPs for sludge dewatering and offer perspectives and directions towards the new-generation of WWTPs with the sustainable and eco-friendly benefits.
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Affiliation(s)
- Jialin Liang
- Engineering and Technology Research Center for Agricultural Land Pollution Integrated Prevention and Control of Guangdong Higher Education Institute, College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - 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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15
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Wang Y, Zheng G, Wang D, Zhou L. Occurrence of bacterial and viral fecal markers in municipal sewage sludge and their removal during sludge conditioning processes. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 310:114802. [PMID: 35228166 DOI: 10.1016/j.jenvman.2022.114802] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/08/2022] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
Fecal contamination in wastewater treatment system may pose severe threats to human health, but the detailed contamination of fecal bacterial and viral pathogens in municipal sewage sludge remains unclear. In addition, it is also unclear how sludge conditioning treatments would impact the distribution of fecal markers in conditioned sewage sludge. Before addressing these two issues, the possible polymerase chain reaction (PCR) inhibition effect when determining the abundances of fecal markers in both sludge solids and sludge supernatants should be solved, and methods of effectively concentrating fecal markers from sludge supernatant should also be developed. In the present study, we found that the serial tenfold dilution effectively reduced the PCR inhibition effect when determining the abundances of fecal markers including cross-assembly phages (CrAssphage), JC polyomavirus (JCPyV), human-specific HF183 bacteroides (HF183), human BK polyomavirus (BKPyV), human adenovirus (HAdV) and Escherichia coli (EC), while the utilization of negatively charged HA membrane was effective to recover fecal markers from sludge supernatant. The results of a six-month monitoring revealed that gene markers of CrAssphage, JCPyV, HF183, BKPyV, HAdV, and EC can be detected in municipal sewage sludge collected from a local wastewater treatment plant. Among the investigated four chemical conditioning methods, i.e., chemical conditioning with polyacrylamide (PAM), Fe[III]/CaO, or Fenton's reagent, and chemical acidification conditioning, chemical conditioning with Fenton's reagent was much more effective than the other three conditioning methods to reduce the abundances of fecal markers in the supernatant and solid of conditioned sewage sludge. Furthermore, the investigated fecal markers in the conditioned sewage sludge can be simultaneously attenuated by employing suitable conditioning methods, consequently reducing the associated environmental risks.
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Affiliation(s)
- Yuhang Wang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China; College of Materials and Chemical Engineering, Pingxiang University, Pingxiang, 337055, 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.
| | - Dianzhan Wang
- Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, 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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16
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Yang Y, Yang X, Wang X, Yang Q, Xu W, Li Y. Explore the closed-loop disposal route of surplus sludge: Sludge self-circulation preparation of sludge-based biochar (SBB) to enhance sludge dewaterability. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128304] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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17
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Lin W, Ding A, Ngo HH, Ren Z, Nan J, Li G, Ma J. Effects of the metabolic uncoupler TCS on residual sludge treatment: Analyses of the microbial community and sludge dewaterability potential. CHEMOSPHERE 2022; 288:132473. [PMID: 34624348 DOI: 10.1016/j.chemosphere.2021.132473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 09/03/2021] [Accepted: 10/03/2021] [Indexed: 06/13/2023]
Abstract
Residual sludge is a by-product with a large volume and complex composition from wastewater treatment plants. It is significant to reduce sludge volume to decrease the negative effects of sludge on environmental pollution and needless land use. We investigated the effects of uncoupler 3, 3', 4', 5-tetrachlorosalicylanilide (TCS) on the properties of sludge. After adding 0.12 g TCS/g VSS with 24 h mixing, the sludge concentration and total ATP content decreased by 51.1% and 60.8%, respectively. At the same time, the microbial community also changed significantly, leading to the decrease of richness and diversity. Additionally, the secretion of extracellular polymeric substances (EPS) reduced approximately 43% under the addition of 0.12 g/g VSS compared with the control. The decrement of EPS may be explained by the decreased relative abundance of functional bacteria (i.e. Chloroflexi reduced about 60% and Nitrospirota reduced about 31%). Notably, the addition of TCS before coagulation conditioning (FeCl3) promoted the adhesion of sludge flocs according to the theory of Extended Derjaguin Landau Verwey Overbee (XDLVO), leading to the increased hydrophobicity of the residual sludge. Therefore, energy uncoupling has the potential of improving sludge dewaterability.
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Affiliation(s)
- Wei Lin
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - An Ding
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China.
| | - Huu Hao Ngo
- Faculty of Engineering, University of Technology Sydney, P.O. Box 123, Broadway, Sydney, NSW 2007, Australia
| | - Zixiao Ren
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Jun Nan
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Guibai Li
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
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18
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Zhou L, Dong N, Ye B, Zhuang WQ, Xia S. Assessing effects of Ca 2+ addition on membrane bioreactor performance and macro-floc sludge characteristics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 798:149223. [PMID: 34375270 DOI: 10.1016/j.scitotenv.2021.149223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/15/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
Calcium ions (Ca2+) can trigger coagulation-flocculation process to form macro-flocculated sludge (MFS). Thus, dosing Ca2+-containing reagents into membrane bioreactors (MBRs) is considered as a promising approach to mitigate membrane biofouling. However, a mechanistic understanding of Ca2+ addition to MBR performance remains elucidated, such as physicochemical characteristics of MFS and their functionality variations. Consequently, this study was sought to understand the interplays of Ca2+ addition and MBR performance with a focus on characterizing MFS in detail. Three parallel MBRs were amended with 82, 208 and 410 mg-Ca2+/L final concentrations. Particle size analyses revealed that MFS formation was overall enhanced by the Ca2+ addition and granular sludge with diameters of up to 900 μm was formed in the 410 mg-Ca2+/L scenario. We believed that cationic bridges facilitated by elevated Ca2+ concentrations in conjunction with coagulation-flocculation were primary mechanisms of the formation of large flocs. Moreover, significant portions of soluble proteins and polysaccharides were flocculated and precipitated by Ca2+, which demonstrated a negative correlation between extracellular polymeric substances (EPS) concentrations and the formation of MFS. Furthermore, the population abundancies of Thiotrichaceae, Sphingomonadales and Hyphomicrobiaceae decreased in the sludge with Ca2+ addition resulted in profound changes of the microbial communities in the MBRs. But MBR performance, such as chemical oxygen demand removal (over 90%), showed no variation during the MBR operation. On the contrary, total nitrogen removal was inhibited in the MBRs. It was because the enlarging MFS formed diffusion barriers to prevent organic component from entering into the sludge flocs to be consumed.
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Affiliation(s)
- Lijie Zhou
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China.
| | - Nan Dong
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China
| | - Biao Ye
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, PR China
| | - Wei-Qin Zhuang
- Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142, New Zealand
| | - Siqing Xia
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, PR China.
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19
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Effects of Air Temperature and Humidity on the Kinetics of Sludge Drying at Low Temperatures. ENERGIES 2021. [DOI: 10.3390/en14227722] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this study, a low-air temperature sludge drying system was constructed and the effects of temperature and relative humidity on the characteristics of the system were investigated. The results showed that the drying rate of sludge increased with an increase in air temperature and a decrease in the air’s relative humidity. The influence of temperature on the average drying rate exhibited an approximate quadratic distribution, while the influence of relative humidity on the average drying rate exhibited an almost linear distribution. The relationship equations of the average drying rate, temperature, and humidity were summarized and compared with the experimental results, and the maximum relative error was 7.6375%. By comparing the experimental results with the commonly used thin-layer drying models, it was found that the sludge drying characteristics were more consistent with the Midilli model. Based on the relevant parameters of the Midilli model, the relationship between the segmented drying moisture content and the average drying rate was proposed, and the empirical formula of the drying rate and MR under different conditions was fitted.
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20
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Wang Y, Si Y, Yang S, Singh RP. Study on Flow Distribution Pattern and Conductivity of Porous Media in Bioretention Cells. Bioengineered 2021; 12:12740-12754. [PMID: 34747297 PMCID: PMC8809911 DOI: 10.1080/21655979.2021.1997131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
To evaluate the long-term performance of bioretention cell (BRC), a study was undertaken to assess the flow distribution and conductivity. Despite initial conductivity of the original medium being the common predictor of hydraulic performance, most of the BRCs are affected by conductivity variations during actual operation. This happen due to the fact that microbial behavior plays an important role in the conductivity variations. This linkage may occur when bacteria as inert colloids transports between particles and biodegrades dissolved pollutants, either promoting or retarding flow distribution and conductivity in BRC. Flow distribution was determined by numerical simulation and tracer test, and the correlation between conductivity and flow distribution was revealed by conductivity experiment coupled with flow distribution analysis. Results revealed a non-uniform flow distribution in BRC, and seepage flow in submerged zone was virtually impossible push flow. Conductivity had an inversely proportional relationship with hydraulic efficiency where hydraulic efficiency reached the highest value (0.297) under a low hydraulic conductivity (0.000107 m/s, approximately K/Kini = 0.79). Primary cause of hydraulic capacity reduction was the initial permeability decrease due to medium structure changes. Results revealed a sharp upward trend followed by a slight decrease, and then, stabilized to a stable infiltration stage. Permeation process of sewage influent was similar to the one of potable water where the permeability reduced to 0.000102 m/s after 450 h and declined continuously. Thus, it is clear that flow distribution and conductivity in bioretention must be estimated more accurately on a microscopic scale.
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Affiliation(s)
- Yajun Wang
- School of Civil Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China.,Western Engineering Research Center of Disaster Mitigation in Civil Engineering of Education, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
| | - Yunmei Si
- School of Civil Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
| | - Sheng Yang
- School of Civil Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
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21
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Liang J, Liao X, Ye M, Guan Z, Mo Z, Yang X, Huang S, Sun S. Dewaterability improvement and environmental risk mitigation of waste activated sludge using peroxymonosulfate activated by zero-valent metals: Fe 0 vs. Al 0. CHEMOSPHERE 2021; 280:130686. [PMID: 33957470 DOI: 10.1016/j.chemosphere.2021.130686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/10/2021] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
The stabilization and dewaterability of waste activated sludge (WAS) are essential factors for downstream disposal or reuse. Herein, two types of zero-valent metals, zero-valent iron (Fe0) and zero-valent aluminum (Al0), were compared for their ability to activate peroxymonosulfate (PMS) during the WAS conditioning process, with the effects of PMS activation by these two metals on WAS dewaterability and the potential environmental risks evaluated. Results showed that compared to Al0/PMS treatment, Fe0/PMS treatment achieved superior WAS dewaterability and reduced operational costs. Using PMS combined with Fe0 and Al0 treatments under optimal conditions, the water content (Wc) of dewatered sludge decreased to 55.7 ± 2.7 wt% and 59.4 ± 1.3 wt%, respectively. Meanwhile, application of the Fe0/PMS treatment system reduced the total annual cost by approximately 33.1%, compared to the Al0/PMS treatment. Analysis of the dewatering mechanism demonstrated that in the Fe0/PMS treatment, Fe3+/Fe2+ flocculation played an important role in the enhancement of WAS dewatering, while sulfate radical (SO4•-) oxidation was the dominant factor for WAS dewaterability improvement in Al0/PMS treatment. The greater enhancement of WAS dewaterability by Fe0/PMS treatment, was mainly attributed to more efficient reduction of hydrophilic extracellular polymeric substances (EPS) and an increase in surface charge neutralization. Environmental risk evaluation results indicated that Fe0/PMS and Al0/PMS treatments both effectively alleviated the environmental risks of heavy metals and faecal coliforms in dewatered sludge. Overall, this study proposes a novel perspective for the selection of an optimal PMS activator in sludge treatment.
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Affiliation(s)
- Jialin Liang
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China; Institute of Bioresource and Agriculture, Department of Biology, Hong Kong Baptist University, Hong Kong
| | - Xiaojian Liao
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China
| | - Maoyou Ye
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - Zhijie Guan
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China
| | - Zhihua Mo
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China
| | - Xian Yang
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China
| | - Shaosong Huang
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China.
| | - Shuiyu Sun
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China; Guangdong Polytechnic of Environmental Protection Engineering, Foshan, 528216, China.
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