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Baffoe EE, Otoo SL, Kareem S, Dankwah JR. Evaluation of initial pH and urea hydrogen peroxide (UHP) co-pretreatment on waste-activated sludge. ENVIRONMENTAL RESEARCH 2024; 246:118155. [PMID: 38211719 DOI: 10.1016/j.envres.2024.118155] [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: 06/27/2023] [Revised: 01/05/2024] [Accepted: 01/06/2024] [Indexed: 01/13/2024]
Abstract
Wastewater treatment and conversion into renewable energy sources have been of great interest in recent times due to growing environmental pollution concerns and need for sustainable energy sources. Sewage sludge treatment can convert sludge into renewable energy. In this study, the impact of initial pH and urea hydrogen peroxide (UHP) co-pretreatment on sludge hydrolysis and anaerobic digestion was investigated. The pH of sludge was initially adjusted to 7, 9, and 11 before the addition of 8 mmol/g VS UHP. Under 24 h pretreatment, alkaline medium and UHP effectively enhanced sludge solubilization and hydrolysis. The combination of chemical, sonication, and centrifugation improved the extraction of extracellular polymerase substances released in soluble state. Secondly, anaerobic digestion was performed for 11 days to determine the influence of a lower mesophilic temperature (20 °C) and retention time on the pretreated sludge. The highest NH4+-N concentration of 5.32 g/L was recorded in pH 7+UHP. The most significant total VFA concentration of 13.1 g COD/L was observed in pH 7+UHP on day 9. Acetic acid, isovaleric acid and propionic acid accounted for 80%-83% of the total VFA composition in all pretreated reactors. Lower mesophilic temperature efficiently optimized UHP and VFA production in the pretreated reactors. Microbial metabolism was stabilized under a longer retention time. Alkaline pH and longer retention time elevated NH4+-N and VFA concentration. The results showed that initial pH and UHP co-pretreatment of waste activated sludge offer an alternative pathway for enhancing sludge hydrolysis and VFA production applicable in sludge treatment.
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Affiliation(s)
- Estella Efiba Baffoe
- School of Resources & Environmental Engineering, Wuhan University of Technology, Wuhan, Hubei Province, 430070, China.
| | - Samuel Leumas Otoo
- School of Materials Science & Engineering, Wuhan University of Technology, Wuhan, Hubei Province, 430070, China
| | - Shefiu Kareem
- School of Materials Science & Engineering, Wuhan University of Technology, Wuhan, Hubei Province, 430070, China
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Zhang J, Long Z, Liu X, He H, Zhang G, Tian Y. Structure and composition of dissolved organic matters in sludge by ultrasonic treatment. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 356:120589. [PMID: 38531126 DOI: 10.1016/j.jenvman.2024.120589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 01/20/2024] [Accepted: 03/10/2024] [Indexed: 03/28/2024]
Abstract
The leaching of dissolved organic matter (DOM) from the sludge into the liquid phase is induced by ultrasound. However, there is limited investigation into the structure and molecular composition of sludge DOM in this process. The molecular structure and composition of sludge DOM in ultrasonic treatment were comprehensively elucidated in this study. The sludge dissolved organic carbon (DOC) and three-dimensional fluorescence spectroscopy (3D-EEM) image had most significant change at 15-min ultrasonic time and 1.2 W/mL ultrasonic density, respectively. Gas Chromatography-Mass Spectrometry (GC-MS) analysis indicated that ultrasonic treatment of sludge reduced the macromolecules to small molecules in DOM. Then, electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS) analysis revealed that lignin, tannins, and carbohydrates were the main components of sludge DOMs after ultrasound treatment. analysis revealed that lignin, tannins, and carbohydrates were the main components of sludge DOMs after ultrasound treatment. Furthermore, through the Van Krevelen analysis, the major components were CHO (48.50%) and CHOS (23.20%) in the DOM of ultrasonicated sludge. This research provides the basis for the practical application of ultrasonic treatment of sludge and provides basic information for DOM components.
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Affiliation(s)
- Jie Zhang
- School of Energy & Environmental Engineering, Tianjin Key Laboratory of Clean Energy and Pollution Control, Hebei University of Technology, Tianjin, 300401, China
| | - Zeqing Long
- Department of Public Health and Preventive Medicine, Changzhi Medical College, Changzhi, 046000, China
| | - Xiaoyang Liu
- School of Energy & Environmental Engineering, Tianjin Key Laboratory of Clean Energy and Pollution Control, Hebei University of Technology, Tianjin, 300401, China
| | - Hui He
- School of Energy & Environmental Engineering, Tianjin Key Laboratory of Clean Energy and Pollution Control, Hebei University of Technology, Tianjin, 300401, China
| | - Guangming Zhang
- School of Energy & Environmental Engineering, Tianjin Key Laboratory of Clean Energy and Pollution Control, Hebei University of Technology, Tianjin, 300401, China.
| | - Yu Tian
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
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Zhu R, Zhao S, Ju C, Yang Q, Cui C, Wu L, Wang M, Feng L, Wu Y. Ultrasonic-assisted hypochlorite activation accelerated volatile fatty acids production during sewage sludge fermentation: Critical insights on solubilization/hydrolysis stages and microbial traits. BIORESOURCE TECHNOLOGY 2023; 383:129233. [PMID: 37244311 DOI: 10.1016/j.biortech.2023.129233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/19/2023] [Accepted: 05/21/2023] [Indexed: 05/29/2023]
Abstract
The effective disruption of extracellular polymeric substances using appropriate pretreatment is critical to achieving resource recovery from sewage sludge (SS) by anaerobic fermentation. This work proposed an ultrasonic-assisted hypochlorite activation strategy for enhanced production of volatile fatty acids (VFAs) during SS fermentation. The results demonstrated that after individual ultrasonic and hypochlorite pretreatment, the maximum VFAs yield improved by 8 and 107% with that in control, respectively, while a combination of both techniques led to an improvement of 119%, indicating their synergistic effects on SS fermentation. This method enhanced the solubilization and hydrolysis efficiencies and contributed to the increased biodegradable substrates, which would be beneficial in enhancing microbial activity for VFAs production. The functional anaerobes, metabolic pathways, and gene expressions involved in VFAs biosynthesis were effectively improved. This work would bring a novel insight into the disposal of municipal solid waste for resource recovery.
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Affiliation(s)
- Rui Zhu
- Jiangsu Environmental Engineering Technology Co., Ltd., Jiangsu Environmental Protection Group Co., Ltd., Nanjing 210036, China
| | - Shanshan Zhao
- Jiangsu Environmental Engineering Technology Co., Ltd., Jiangsu Environmental Protection Group Co., Ltd., Nanjing 210036, China
| | - Chenlu Ju
- Jiangsu Environmental Engineering Technology Co., Ltd., Jiangsu Environmental Protection Group Co., Ltd., Nanjing 210036, China
| | - Qing Yang
- Jiangsu Environmental Engineering Technology Co., Ltd., Jiangsu Environmental Protection Group Co., Ltd., Nanjing 210036, China
| | - Chengcheng Cui
- Jiangsu Environmental Engineering Technology Co., Ltd., Jiangsu Environmental Protection Group Co., Ltd., Nanjing 210036, China
| | - Lijuan Wu
- Jiangsu Environmental Engineering Technology Co., Ltd., Jiangsu Environmental Protection Group Co., Ltd., Nanjing 210036, China
| | - Min Wang
- Jiangsu Society Environmental Sciences, Nanjing 210019, China
| | - Leiyu Feng
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yang Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
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Recent Advances and Perspectives of Nanotechnology in Anaerobic Digestion: A New Paradigm towards Sludge Biodegradability. SUSTAINABILITY 2022. [DOI: 10.3390/su14127191] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Anaerobic digestion (AD) is the strategy of producing environmentally sustainable bioenergy from waste-activated sludge (WAS), but its efficiency was hindered by low biodegradability. Hence, the usage of nanomaterials was found to be essential in enhancing the degradability of sludge due to its nanostructure with specific physiochemical properties. The application of nanomaterials in sludge digestion was thoroughly reviewed. This review focused on the impact of nanomaterials such as metallic nanoparticles, metal oxide nanoparticles, carbon-based nanomaterials, and nanocomposite materials in AD enhancement, along with the pros and cons. Most of the studies detailed that the addition of an adequate dosage of nanomaterial has a good effect on microbial activity. The environmental and economic impact of the AD enhancement process is also detailed, but there are still many existing challenges when it comes to designing an efficient, cost-effective AD digester. Hence, proper investigation is highly necessary to assess the potency of utilizing the nanomaterials in enhancing AD under various conditions.
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