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Wang Y, Guo H, Li X, Chen X, Peng L, Zhu T, Sun P, Liu Y. Peracetic acid (PAA)-based pretreatment effectively improves medium-chain fatty acids (MCFAs) production from sewage sludge. ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY 2024; 20:100355. [PMID: 38192428 PMCID: PMC10772567 DOI: 10.1016/j.ese.2023.100355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/17/2023] [Accepted: 11/23/2023] [Indexed: 01/10/2024]
Abstract
Peracetic acid (PAA), known for its environmentally friendly properties as a oxidant and bactericide, is gaining prominence in decontamination and disinfection applications. The primary product of PAA oxidation is acetate that can serve as an electron acceptor (EA) for the biosynthesis of medium-chain fatty acids (MCFAs) via chain elongation (CE) reactions. Hence, PAA-based pretreatment is supposed to be beneficial for MCFAs production from anaerobic sludge fermentation, as it could enhance organic matter availability, suppress competing microorganisms and furnish EA by providing acetate. However, such a hypothesis has rarely been proved. Here we reveal that PAA-based pretreatment leads to significant exfoliation of extracellular polymeric substances (EPS) from sludge flocs and disruption of proteinic secondary structures, through inducing highly active free radicals and singlet oxygen. The production of MCFAs increases substantially to 11,265.6 mg COD L-1, while the undesired byproducts, specifically long-chain alcohols (LCAs), decrease to 723.5 mg COD L-1. Microbial activity tests further demonstrate that PAA pretreatment stimulates the CE process, attributed to the up-regulation of functional genes involved in fatty acid biosynthesis pathway. These comprehensive findings provide insights into the effectiveness and mechanisms behind enhanced MCFAs production through PAA-based technology, advancing our understanding of sustainable resource recovery from sewage sludge.
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Affiliation(s)
- Yufen Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Haixiao Guo
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Xuecheng Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Xueming Chen
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fujian, 350116, China
| | - Lai Peng
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Peizhe Sun
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
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2
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Jiang T, Li X, Yang J, Wang L, Wang W, Zhang L, Wang B. Potential of free nitrous acid (FNA) for sludge treatment and resource recovery from waste activated sludge: A review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 360:121170. [PMID: 38749134 DOI: 10.1016/j.jenvman.2024.121170] [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: 11/27/2023] [Revised: 04/18/2024] [Accepted: 05/11/2024] [Indexed: 06/05/2024]
Abstract
The escalating production of waste activated sludge (WAS) presents significant challenges to wastewater treatment plants (WWTPs). Free nitrous acid (FNA), known for its biocidal effect, has gained a growing focus on sludge dewatering, sludge reduction, and resource recovery from WAS due to its eco-friendly and cost-effective properties. Nevertheless, there have been no attempts made to systematically summarize or critically analyze the application of FNA in enhancing treatment and resource utilization of sludge. In this paper, we provided an overview of the current understanding regarding the application potential and influencing factors of FNA in sludge treatment, with a specific focus on enhancing sludge dewatering efficiency and reducing volume. To foster resource development from sludge, various techniques based on FNA have recently been proposed, which were comprehensively reviewed with the corresponding mechanisms meticulously discussed. The results showed that the chemical oxidation and interaction with microorganisms of FNA played the core role in improving resource utilization. Furthermore, current challenges and future prospects of the FNA-based applications were outlined. It is expected that this review can refine the theoretical framework of FNA-based processes, providing a theoretical foundation and technical guidance for the large-scale demonstration of FNA.
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Affiliation(s)
- Tan Jiang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Xiaodi Li
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Jiayi Yang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Lu Wang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Wen Wang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Li Zhang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Bo Wang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China.
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3
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Gu X, Sun J, Wang T, Li J, Wang H, Wang J, Wang Y. Comprehensive review of microbial production of medium-chain fatty acids from waste activated sludge and enhancement strategy. BIORESOURCE TECHNOLOGY 2024; 402:130782. [PMID: 38701982 DOI: 10.1016/j.biortech.2024.130782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 04/30/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024]
Abstract
Microbial production of versatile applicability medium-chain fatty acids (MCFAs) (C6-C10) from waste activated sludge (WAS) provides a pioneering approach for wastewater treatment plants (WWTPs) to achieve carbon recovery. Mounting studies emerged endeavored to promote the MCFAs production from WAS while struggling with limited MCFAs production and selectivity. Herein, this review covers comprehensive introduction of the transformation process from WAS to MCFAs and elaborates the mechanisms for unsatisfactory MCFAs production. The enhancement strategies for biotransformation of WAS to MCFAs was presented. Especially, the robust performance of iron-based materials is highlighted. Furthermore, knowledge gaps are identified to outline future research directions. Recycling MCFAs from WAS presents a promising option for future WAS treatment, with iron-based materials emerging as a key regulatory strategy in advancing the application of WAS-to-MCFAs biotechnology. This review will advance the understanding of MCFAs recovery from WAS and promote sustainable resource management in WWTPs.
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Affiliation(s)
- Xin Gu
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jing Sun
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Tong Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jia Li
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Han Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jialin Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yayi Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
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4
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Liu Y, Ye X, Chen K, Wu X, Jiao L, Zhang H, Zhu F, Xi Y. Effect of nanobubble water on medium chain carboxylic acids production in anaerobic digestion of cow manure. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 184:37-51. [PMID: 38795539 DOI: 10.1016/j.wasman.2024.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/30/2024] [Accepted: 05/20/2024] [Indexed: 05/28/2024]
Abstract
Nanobubble water promotes the degradation of difficult-to-degrade organic matter, improves the activity of electron transfer systems during anaerobic digestion, and optimizes the composition of anaerobic microbial communities. Therefore, this study proposes the use of nanobubble water to improve the yield of medium chain carboxylic acids produced from cow manure by chain elongation. The experiment was divided into two stages: the first stage involved the acidification of cow manure to produce volatile acidic fatty acids as electron acceptors, and the second phase involved the addition of lactic acid as an electron donor for the chain elongation. Three experimental groups were established, and air, H2, and N2 nanobubble water were added in the second stage. Equal amounts of deionized water were added in the control group. The results showed that nanobubble water supplemented with air significantly increased the caproic acid concentration to 15.10 g/L, which was 55.03 % greater than that of the control group. The relative abundances of Bacillus and Caproiciproducens, which are involved in chain elongation, and Syntrophomonas, which is involved in electron transfer, increased. The unique ability of air nanobubble water supplemented to break down the cellulose matrix resulted in further decomposition of the recalcitrant material in cow manure. This effect subsequently increased the number of microorganisms associated with lignocellulose degradation, increasing carbohydrate metabolism and ATP-binding cassette transporter protein activity and enhancing fatty acid cycling pathways during chain elongation. Ultimately, this approach enabled the efficient production of medium chain carboxylic acids.
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Affiliation(s)
- Yang Liu
- Jiangsu Academy of Agriculture Sciences, Nanjing 210014, China; Key Laboratory of Crop and Livestock Integration, Ministry of Agriculture and Rural Affairs, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, 210014 Nanjing, China; State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical, Nanjing Tech University, Nanjing 210009, China
| | - Xiaomei Ye
- Jiangsu Academy of Agriculture Sciences, Nanjing 210014, China; Key Laboratory of Crop and Livestock Integration, Ministry of Agriculture and Rural Affairs, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, 210014 Nanjing, China
| | - Kequan Chen
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical, Nanjing Tech University, Nanjing 210009, China
| | - Xiayuan Wu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical, Nanjing Tech University, Nanjing 210009, China
| | - Lihua Jiao
- Jiangsu Academy of Agriculture Sciences, Nanjing 210014, China; Key Laboratory of Crop and Livestock Integration, Ministry of Agriculture and Rural Affairs, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, 210014 Nanjing, China
| | - Hongyu Zhang
- Jiangsu Academy of Agriculture Sciences, Nanjing 210014, China; Key Laboratory of Crop and Livestock Integration, Ministry of Agriculture and Rural Affairs, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, 210014 Nanjing, China
| | - Fei Zhu
- Jiangsu Academy of Agriculture Sciences, Nanjing 210014, China; Key Laboratory of Crop and Livestock Integration, Ministry of Agriculture and Rural Affairs, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, 210014 Nanjing, China
| | - Yonglan Xi
- Jiangsu Academy of Agriculture Sciences, Nanjing 210014, China; Key Laboratory of Crop and Livestock Integration, Ministry of Agriculture and Rural Affairs, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, 210014 Nanjing, China; Department of Applied Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcka 129, Praha-Suchdol 16500, Czech Republic.
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Liu Y, Duan Y, Chen L, Yang Z, Yang X, Liu S, Song G. Research on the Resource Recovery of Medium-Chain Fatty Acids from Municipal Sludge: Current State and Future Prospects. Microorganisms 2024; 12:680. [PMID: 38674623 PMCID: PMC11051992 DOI: 10.3390/microorganisms12040680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
The production of municipal sludge is steadily increasing in line with the production of sewage. A wealth of organic contaminants, including nutrients and energy, are present in municipal sludge. Anaerobic fermentation can be used to extract useful resources from sludge, producing hydrogen, methane, short-chain fatty acids, and, via further chain elongation, medium-chain fatty acids. By comparing the economic and use values of these retrieved resources, it is concluded that a high-value resource transformation of municipal sludge can be achieved via the production of medium-chain fatty acids using anaerobic fermentation, which is a hotspot for future research. In this study, the selection of the pretreatment method, the method of producing medium-chain fatty acids, the influence of the electron donor, and the technique used to enhance product synthesis in the anaerobic fermentation process are introduced in detail. The study outlines potential future research directions for medium-chain fatty acid production using municipal sludge. These acids could serve as a starting point for investigating other uses for municipal sludge.
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Affiliation(s)
- Yuhao Liu
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450046, China; (Y.D.); (L.C.); (Z.Y.); (X.Y.); (S.L.); (G.S.)
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Wang Y, Chen F, Guo H, Sun P, Zhu T, Horn H, Liu Y. Permanganate (PM) pretreatment improves medium-chain fatty acids production from sewage sludge: The role of PM oxidation and in-situ formed manganese dioxide. WATER RESEARCH 2024; 249:120869. [PMID: 38007897 DOI: 10.1016/j.watres.2023.120869] [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: 09/16/2023] [Revised: 11/03/2023] [Accepted: 11/12/2023] [Indexed: 11/28/2023]
Abstract
Medium-chain fatty acids (MCFAs) production from sewage sludge is mainly restricted by the complex substrate structure, competitive metabolism and low electron transfer rate. This study proposes a novel permanganate (PM)-based strategy to promote sludge degradation and MCFAs production. Results show that PM pretreatment significantly increases MCFAs production, i.e., attaining 12,036 mg COD/L, and decreases the carbon fluxes of electron acceptor (EA)/electron donor (ED) to byproducts. Further analysis reveals that PM oxidation enhances the release and biochemical conversion of organic components via disrupting extracellular polymers (EPS) structure and reducing viable cells ratio, providing directly available EA for chain elongation (CE). The microbial activity positively correlated with MCFAs generation are apparently heightened, while the competitive metabolism of CE (i.e., methanogensis) can be completely inhibited. Accordingly, the functional bacteria related to critical bio-steps and dissimilatory manganese reduction are largely enriched. Further mechanism exploration indicates that the main contributors for sludge solubilization are 1O2 (61.6 %) and reactive manganese species (RMnS), i.e., Mn(V)/Mn(VI) (22.3 %) and Mn(III) (∼16.1 %). As the main reducing product of PM reaction, manganese dioxide (MnO2) can enable the formation of microbial aggregates, and serve as electron shuttles to facilitate the carbon fluxes to MCFAs during CE process. Overall, this strategy can achieve simultaneous hydrogen recovery, weaken competitive metabolisms and provide electron transfer accelerator for CE reactions.
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Affiliation(s)
- Yufen Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Feng Chen
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Haixiao Guo
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Peizhe Sun
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Harald Horn
- Engler-Bunte-Institut, Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, Karlsruhe 76131, Germany
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
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7
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Wang Y, Zhang Z, Wang X, Guo H, Zhu T, Ni BJ, Liu Y. Percarbonate-strengthened ferrate pretreatment for enhancing short-chain fatty acids production from sewage sludge. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166771. [PMID: 37660812 DOI: 10.1016/j.scitotenv.2023.166771] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 08/20/2023] [Accepted: 08/31/2023] [Indexed: 09/05/2023]
Abstract
Sewage sludge management poses a pressing environmental challenge, demanding the implementation of sustainable solutions to facilitate resource recovery. Short-chain fatty acids (SCFAs) serve as valuable chemicals and renewable energy sources, underscoring the importance of maximizing their production to achieve sustainable waste management. Therefore, this study proposes a novel and green strategy, i.e., percarbonate-strengthened ferrate pretreatment to enhance SCFAs synthesis from sewage sludge, because percarbonate could activate ferrate oxidation through providing (bi) carbonate and hydrogen peroxide. Results show that percarbonate largely reduces the required ferrate dosage for fermentation improvement, and their combination exhibits obvious synergistic effects on SCFAs accumulation and sludge reduction. Under the optimal pretreatment conditions, SCFAs production is promoted to 3670.2 mg COD/L, representing a remarkable increase of 5512.4 %, 156.0 % or 395.1 % compared to the control, percarbonate alone or ferrate alone, respectively. Mechanism explorations demonstrate that percarbonate-strengthened ferrate pretreatment significantly enhances sludge solubilization, elevates substrate biodegradability, and alters the physiochemical properties of sludge to favor organics fermentation. The synergistic effects on solid organics release and sludge properties can be attributed to the combined mechanisms of enhanced oxidation and alkaline hydrolysis. Further investigations on metabolic pathways reveal that the combination substantially improves key enzyme activities associated with hydrolysis and SCFAs formation, while severely inhibits that of SCFAs consumption. These findings are further supported by the functional genes coding relevant enzymes. Moreover, the combination alters microbial structures and compositions, leading to the screening and enrichment of key microbes that facilitate SCFAs accumulation. This innovative strategy holds significant promise in advancing sewage sludge management towards a more circular and resource-efficient paradigm.
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Affiliation(s)
- Yufen Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Zixin Zhang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Xiaomin Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Haixiao Guo
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Bing-Jie Ni
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
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Huo W, Ye R, Shao Y, Bao M, Stegmann R, Lu W. Enhanced ethanol-driven carboxylate chain elongation by Pt@C in simulated sequencing batch reactors: Process and mechanism. BIORESOURCE TECHNOLOGY 2023:129310. [PMID: 37315622 DOI: 10.1016/j.biortech.2023.129310] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/06/2023] [Accepted: 06/08/2023] [Indexed: 06/16/2023]
Abstract
Carboxylate chain elongation can create value-added bioproducts from the organic waste. The effects of Pt@C on chain elongation and associated mechanisms were investigated in simulated sequencing batch reactors. 5.0 g/L of Pt@C greatly increased the synthesis of caproate, with an average yield of 21.5 g COD/L, which was 207.4% higher than the trial without Pt@C. Integrated metagenomic and metaproteomic analyses were used to reveal the mechanism of Pt@C-enhanced chain elongation. Pt@C enriched chain elongators by increasing the relative abundance of dominant species by 115.5%. The expression of functional genes related to chain elongation was promoted in the Pt@C trial. This study also demonstrates that Pt@C may promote overall chain elongation metabolism by enhancing CO2 uptake of Clostridium kluyveri. The study provides insights into the fundamental mechanisms of how chain elongation can perform CO2 metabolism and how it can be enhanced by Pt@C to upgrade bioproducts from organic waste streams.
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Affiliation(s)
- Weizhong Huo
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Rong Ye
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Yuchao Shao
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Menggang Bao
- School of Environment, Tsinghua University, Beijing 100084, China
| | | | - Wenjing Lu
- School of Environment, Tsinghua University, Beijing 100084, China.
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9
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Zhang L, Wang X, Chen Y, Zhang B, Xu H, Li C, Zhou Y. Medium-chain fatty acid production from thermal hydrolysed sludge without external electron donor supplementation. BIORESOURCE TECHNOLOGY 2023; 374:128805. [PMID: 36849100 DOI: 10.1016/j.biortech.2023.128805] [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: 01/08/2023] [Revised: 02/11/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
In this study, medium-chain fatty acid (MCFA) generation from mixed sludge (including primary sludge and waste activated sludge) was investigated without additional electron donors (EDs). 0.5 g COD/L of MCFAs was produced and the in situ generated ethanol could serve as the EDs during the anaerobic fermentation of mixed sludge without thermal hydrolysis process (THP) pretreatment. THP increased the MCFA production by approximately 128% in the anaerobic fermentation. During 102 days of operation, the fermentation of THP pre-treated mixed sludge stably generated 2.9 g COD/L MCFAs. The self-generated EDs could not maximize MCFA production, and external addition of ethanol improved MCFA yield. Caproiciproducens was the dominant chain-elongating bacteria. PICRUST2 revealed that both fatty acid biosynthesis and reverse β-oxidation pathways could participate in MCFA synthesis, and ethanol addition could enhance the contribution of the reverse β-oxidation pathway. Future studies should focus on the improvement of MCFA production from THP-assisted sludge fermentation.
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Affiliation(s)
- Liang Zhang
- Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China
| | - Xiuping Wang
- Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China
| | - Yun Chen
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore
| | - Baorui Zhang
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore
| | - Hui Xu
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore
| | - Chenchen Li
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore
| | - Yan Zhou
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore.
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10
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Wang X, Wang Y, Zheng K, Tian L, Zhu T, Chen X, Zhao Y, Liu Y. Enhancing methane production from waste activated sludge with heat-assisted potassium ferrate (PF) pretreatment: Reaction kinetics and mechanisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 860:160441. [PMID: 36436650 DOI: 10.1016/j.scitotenv.2022.160441] [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: 09/25/2022] [Revised: 11/10/2022] [Accepted: 11/19/2022] [Indexed: 06/16/2023]
Abstract
This work proposed a novel strategy via heat-assisted potassium ferrate (PF) pretreatment to enhance methane production from waste activated sludge (WAS) during anaerobic digestion. In this research, five dosages of PF (i.e., 0, 0.05, 0.1, 0.3 and 0.5 g/g VSS) at two temperatures (i.e., 25 °C and 55 °C) were explored. Biochemical methane potential experiments illustrated that heat-assisted PF pretreatment improved cumulative methane production with the maximum yield up to 163.93 mL CH4/g VSS, 149.0 %, 119.6 % and 121.0 % of that in the control, individual 0.5 g PF/g VSS and individual heat (i.e., 55 °C) pretreatment digesters, respectively. The maximum methane potential (B0) was promoted by 63.2 % with heat-assisted PF pretreatment compared to the control, while the hydrolysis rate (k) changed slightly. Mechanism analysis revealed that heat-assisted PF pretreatment accelerated WAS solubilization and enhanced the biodegradability of released substances, providing more available matrix for bacteria during the following anaerobic digestion processes. Microbial community analysis exhibited that several microbes such as Proteiniclasticum sp., Sedimentibacter sp. and Methanosaeta sp. associated with hydrolysis, acidification and methanogenesis respectively were improved after heat-assisted PF pretreatment. In addition, the relative bioactivities of protease, butyrate kinase and acetate kinase were also increased. Furthermore, variation of dominant genes associated with methane production indicated that acetate-dependent methanogenesis was the main pathway while CO2-dependent methanogenesis pathway was inhibited by heat-assisted PF pretreatment.
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Affiliation(s)
- Xiaomin Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yufen Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Kaixin Zheng
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Lixin Tian
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Xueming Chen
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fujian 350116, China
| | - Yingxin Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China.
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11
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Wan J, Zhang L, Jia B, Yang B, Luo Z, Yang J, Boguta P, Su X. Effects of enzymes on organic matter conversion in anaerobic fermentation of sludge to produce volatile fatty acids. BIORESOURCE TECHNOLOGY 2022; 366:128227. [PMID: 36332860 DOI: 10.1016/j.biortech.2022.128227] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/23/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Sludge hydrolysis is a vital step in anaerobic digestion of sludge. This study compared the efficacy of free versus immobilized enzymes at different concentrations in promoting sludge disintegration. Pretreatment with 1,000 mg/L immobilized enzymes was more efficient in promoting sludge disintegration than free enzymes at the same concentration. Under the optimized conditions, volatile fatty acids (VFAs) were produced at 10.6 g/L, accounting for 85 % of total soluble chemical oxygen demand. Improved VFA production was attributed to the release of large amounts of polysaccharides and proteins from the enzymatically pretreated sludge. Released organic matter are the substrates for VFAs generated by the determined microbial community of Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, and Chloroflexi. In this study, anaerobic fermentation was used to successfully convert organic matter in sludge into high-value-added VFAs. Therefore, this process can be selected as a strategy to reduce carbon emissions from wastewater treatment plants (WWTPs).
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Affiliation(s)
- Juanjuan Wan
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, China
| | - Lijuan Zhang
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, China; School of Environment, South China Normal University, University Town, Guangzhou, Guangdong 510006, China
| | - Boyu Jia
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, China
| | - Bo Yang
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, China
| | - Zeliang Luo
- College of Electro-mechanical Engineering, Zhuhai City Polytechnic, Zhuhai, Guangdong 519090, China
| | - Jiakuan Yang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Patrycja Boguta
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
| | - Xintai Su
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, China.
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