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Liu Z, Luo F, He L, Wang S, Wu Y, Chen Z. Physical conditioning methods for sludge deep dewatering: A critical review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 360:121207. [PMID: 38788408 DOI: 10.1016/j.jenvman.2024.121207] [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: 01/22/2024] [Revised: 04/17/2024] [Accepted: 05/18/2024] [Indexed: 05/26/2024]
Abstract
Sludge is an inevitable waste product of sewage treatment with a high water content and large volume, it poses a significant threat of secondary pollution to both water and the atmosphere without proper disposal. In this regard, dewatering has emerged as an attractive method in sludge treatment, as it can reduce the sludge volume, enhance its transportability and calorific value, and even decrease the production of landfill leachate. In recent years, physical conditioning methods including non-chemical conditioners or energy input alone, have been extensively researched for their potential to enhance sludge dewatering efficiency, such as thermal treatment, freeze-thaw, microwave, ultrasonic, skeleton builders addition, and electro-dewatering, as well as combined methods. The main objective of this paper is to comprehensively evaluate the dewatering capacity of various physical conditioning methods, and identify key factors affecting sludge dewatering efficiency. In addition, future research anticipated directions and outlooks are proposed. This work is expected to provide valuable insights for developing efficient, eco-friendly, and low-energy consumption techniques for deep sludge dewatering.
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Affiliation(s)
- Zhuo Liu
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Fang Luo
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Lingzhi He
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Siqi Wang
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yi Wu
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhuqi Chen
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
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Udaondo A, Montes V, Gimeno O, Rivas FJ. Excess secondary sludge reuse by H 2O 2 thermal dehydration. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:23023-23036. [PMID: 38418785 PMCID: PMC10997731 DOI: 10.1007/s11356-024-32568-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 02/16/2024] [Indexed: 03/02/2024]
Abstract
The excess of activated sludge generated in municipal wastewater treatment plants constitutes one of the challenging problems facing modern society. The high-water content of this waste makes difficult the transport, disposal, and management of these solids. In this work, activated sludge excess from a secondary clarifier has been dehydrated by means of a combination of temperature and hydrogen peroxide treatment. Three main operating variables have been considered to affect sludge dewaterability and filterability. Temperature (120-180 °C), hydrogen peroxide dose (0.01-0.03 M), and treatment time (20-60 min) influence have been assessed by completing a 15-run Box Behnken experimental design. Different output variables (water content, resistance to filtration, sedimentation volumetric index, extracellular polymeric substances, etc.) have been monitored. Generally, temperature seems to be the most influencing parameter to obtain a dehydrated sludge with acceptable management/disposal characteristics (sludge volume reduction and filterability). In line with the concept of circular economy, an attempt has been conducted to obtain a sustainable biosorbent from the dehydrated sludge generated in the previous stage. Optimum conditions of carbonization and activation revealed that the solid obtained at 400 °C by using ammonium nitrate as activation agent was the most efficient absorbent to eliminate some model compounds from water (namely, phenol, ofloxacin, and diuron); however, a clear improvement margin in the synthesis is foreseen.
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Affiliation(s)
- Ana Udaondo
- Departamento de Ingeniería Química y Química Física, Instituto Universitario de investigación del agua, cambio climático y sostenibilidad, Universidad de Extremadura, Badajoz, Spain
- Departamento de Química Orgánica e Inorgánica, Instituto Universitario de investigación del agua, cambio climático y sostenibilidad, Universidad de Extremadura, Badajoz, Spain
| | - Vicente Montes
- Departamento de Química Orgánica e Inorgánica, Instituto Universitario de investigación del agua, cambio climático y sostenibilidad, Universidad de Extremadura, Badajoz, Spain.
| | - Olga Gimeno
- Departamento de Ingeniería Química y Química Física, Instituto Universitario de investigación del agua, cambio climático y sostenibilidad, Universidad de Extremadura, Badajoz, Spain
| | - Francisco Javier Rivas
- Departamento de Ingeniería Química y Química Física, Instituto Universitario de investigación del agua, cambio climático y sostenibilidad, Universidad de Extremadura, Badajoz, Spain
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Li Z, Chen H. Elucidating the role of solids content in low-temperature thermal hydrolysis and anaerobic digestion of sewage sludge. BIORESOURCE TECHNOLOGY 2022; 362:127859. [PMID: 36037837 DOI: 10.1016/j.biortech.2022.127859] [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: 07/14/2022] [Revised: 08/22/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023]
Abstract
The role of total solids content in low-temperature thermal hydrolysis and anaerobic digestion of sewage sludge was investigated. Increasing total solids from 2% to 6% improved thermal hydrolysis and anaerobic digestion performance, while increasing it further to 12% decreased methane production. Maximum sludge solubility (22.9% ± 0.6%) and methane production (320 ± 7 mL/g volatile solids) were achieved at 6% solids. The increase in solids content from 2% to 6% improved heating efficiency and volatile fraction content, which facilitated sludge solubilization and enrichment of methanogens. However, further increases in solids content resulted in a stable floc structure with excess ammonia nitrogen and volatile fatty acids, which limited the release of substrates and reduced the abundance of acidifying bacteria and methanogens, ultimately leading to reduced methane production. An in-depth understanding of the role of solids content opens up new avenues for improved low-temperature thermal hydrolysis of sludge.
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Affiliation(s)
- Zeyu Li
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Hongbo Chen
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China.
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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. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 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] [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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Li X, Xiao X, Liu Y, Fang G, Wang P, Zou D. Analysis of organic matter conversion behavior and kinetics during thermal hydrolysis of sludge and its anaerobic digestion performance. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 305:114408. [PMID: 34974216 DOI: 10.1016/j.jenvman.2021.114408] [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: 10/09/2021] [Revised: 12/22/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
In thermal hydrolysis (TH) of waste activated sludge (WAS), the material transformation of a specific temperature heating for a set duration is generally examined. However, this study looked at the material changes of TH as the temperature rose (90-210 °C) and the kinetic derivation of soluble chemical oxygen demand (SCOD), protein, and carbohydrate using the Coats-Redfern model. It was found that the proportion of soluble protein and soluble carbohydrate in the organic components and their contents reached the maximum (17.39 and 8.10 g L-1 respectively) at 180 °C. Differently, volatile fatty acid (VFA), amino acids, and ammonia nitrogen increased with the TH temperature and reached a maximum at 210 °C. The fitting equations of non-isothermal dynamics at the medium- and low-temperature stages (90-180 °C) at n = 1, 0.5, and 2 were studied. When n = 1, the activation energies of COD, protein, and carbohydrate were 33.32, 23.34, and 36.15 kJ mol-1, respectively. And the kinetic analysis results were in good agreement with the experimental results (the maximum rate of increase in protein and carbohydrate was at 135-150 °C and 150-180 °C, respectively). Moreover, the pattern of anaerobic digestion performance of WAS was comparable to the trend of protein and carbohydrate in TH, the highest cumulative methane production was 159.68 mL·g-1VS for the TH sludge at 180 °C. This study provided a theoretical foundation for the use of thermal hydrolysis in engineering.
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Affiliation(s)
- Xinxin Li
- Department of Environmental Science & Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Xiong Xiao
- Department of Environmental Science & Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Yanping Liu
- Department of Environmental Science & Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
| | - Gang Fang
- Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Pingbo Wang
- Department of Environmental Science & Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Dexun Zou
- Department of Environmental Science & Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
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Li X, Shi Y, Zhou X, Wang L, Zhang H, Pi K, Gerson AR, Liu D. Adaptability of organic matter and solid content to Fe 2+/persulfate and skeleton builder conditioner for waste activated sludge dewatering. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:14819-14829. [PMID: 34617233 DOI: 10.1007/s11356-021-16404-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 09/03/2021] [Indexed: 06/13/2023]
Abstract
Sludge conditioning is important for improved dewatering, with the sludge characteristics impacting the effect of conditioning. A composite conditioner, Fe2+-activated sodium persulfate (Fe2+/SPS) combined with phosphogypsum (PG), was used to examine its impact on sludges with different organic contents (34.6-43.8%) or different solid contents (2.8-5.9%). Response surface optimization analysis shows that when the best conditioning is achieved, the reduction of the specific resistance to filtration (SRF) is not sensitive to organic matter content, but the dewatering performance of the sludge is greatly affected by the solid content. The oxidation role of Fe2+/SPS and the skeleton builder role of PG together affect the conditioning, oxidation playing a major role in conditioning, especially for greater organic matter content. The organic content (maximum ηSOL value was 0.32) also affects the effectiveness of the skeleton builder more than the solid content (Maximum ηSOL value was 0.25). Changes in PG significantly impacts the optimal molar ratio and dosage of Fe2+/SPS. Sludge with greater solid content requires greater Fe2+/SPS dosage to provide stronger oxidation to destroy flocs, and the maximum Fe2+:SPS molar ratio was 1.14 with solid content of 5.9 wt%. The composite conditioning decreases the content of extracellular polymeric substances and proteins/polysaccharides. This study provides new insight into the relationship between the oxidation role of Fe2+/SPS and the skeleton builder role of PG for sludge conditioning strategies according to the optimal conditions.
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Affiliation(s)
- Xiaoran Li
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China
| | - Yafei Shi
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China.
- Hubei Key Laboratory of Ecological Restoration for River-Lakes and Algal Utilization, Wuhan, 430068, Hubei, China.
| | - Xi Zhou
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China
| | - Lu Wang
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China
| | - Huiqin Zhang
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China
| | - Kewu Pi
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China
- Hubei Key Laboratory of Ecological Restoration for River-Lakes and Algal Utilization, Wuhan, 430068, Hubei, China
| | - Andrea R Gerson
- Blue Minerals Consultancy, Wattle Grove, Tasmania, 7109, Australia
| | - Defu Liu
- School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, Hubei, China
- Hubei Key Laboratory of Ecological Restoration for River-Lakes and Algal Utilization, Wuhan, 430068, Hubei, China
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Fe(NO3)3 assisted hydrothermal carbonization of sewage sludge: Focusing on characteristics of hydrochar and aqueous phase. MOLECULAR CATALYSIS 2021. [DOI: 10.1016/j.mcat.2021.111823] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Ranjbar F, Karrabi M, Danesh S, Gheibi M. Improvement of wastewater sludge dewatering using ferric chloride, aluminum sulfate, and calcium oxide (experimental investigation and descriptive statistical analysis). WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2021; 93:1138-1149. [PMID: 33522044 DOI: 10.1002/wer.1526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 06/12/2023]
Abstract
In this research, application of chemical conditioners for the conditioning of sludge and their effects on the improvement of sludge thickening of the wastewater treatment plant in the city of Bojnourd (Iran) is investigated. The concentration of chemical conditioners, pH and coagulation and flocculation time is from among the parameters studied in this research work. The results obtained indicate that sludge volume reduction for the chemical conditioners used, including Ferric Chloride (FeCl3 ), Aluminum Sulfate (Al2 (SO4 )3 ), and Calcium Oxide (CaO) are 41, 17, and 33 percent, respectively. The optimal concentration for FeCl3 , Al2 (SO4 )3, and CaO are 550, 1100, and 292 mg/L, respectively, and the optimal values of pH are 9, 7.5, and 10, respectively. The time to filtration (TTF) and reduction in sludge moisture content (SMC) for Ferric Chloride, Aluminum Sulfate, and Calcium Oxide are 45 s and 6.2%, 135 s and 3.3%, 190 s and 2.4% respectively. PRACTITIONER POINTS: Investigating the sludge conditioning by Ferric Chloride, Aluminum Sulfate, and Calcium Oxide. Determining the optimal concentration, pH, and coagulation/flocculation time. Calculating the time to filtration (TTF) and reduction in sludge moisture content (SMC). Predicting the settled sludge volume using descriptive statistical analysis.
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Affiliation(s)
- Flora Ranjbar
- Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mohsen Karrabi
- Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Shahnaz Danesh
- Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mohammad Gheibi
- Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
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