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Winkler J, Neuner T, Hupfauf S, Arthofer A, Ebner C, Rauch W, Bockreis A. Impact of impeller design on anaerobic digestion: Assessment of mixing dynamics, methane yield, microbial communities and digestate dewaterability. BIORESOURCE TECHNOLOGY 2024; 406:131095. [PMID: 38986887 DOI: 10.1016/j.biortech.2024.131095] [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: 03/25/2024] [Revised: 06/26/2024] [Accepted: 07/06/2024] [Indexed: 07/12/2024]
Abstract
The efficiency of anaerobic digestion (AD) processes is intricately tied to mixing quality. This research investigates the influence of two impeller types, namely a helical ribbon impeller (HRI) and a pitched-blade impeller (PBI), on key aspects of AD. The investigation encompassed mixing dynamics, methane production, microbial communities, and the previously unexplored impact on digestate dewaterability. Results show that agitation with the PBI exhibited stratification, with bottom layer total solids (TS) values of 3.1% for the PBI and 2.6% for the HRI. Nevertheless, methane yield remained unchanged, averaging 286 LN/kg volatile solids (VS)added. Slower mixing with the HRI achieved more uniform mixing and reduced energy requirements. Additionally, impeller type significantly affected digestate dewaterability, leading to a 3.8% increase in TS of the dewatered sludge when using the PBI. These findings highlight the importance of considering mixing not only for methane production and reduced maintenance but also for achieving optimal digestate dewaterability.
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Affiliation(s)
- Jacqueline Winkler
- Department of Infrastructure, Universität Innsbruck, Technikerstraße 13, A-6020 Innsbruck, Austria.
| | - Thomas Neuner
- MCI, The Entrepreneurial School, Maximilianstraße 2, 6020 Innsbruck, Austria.
| | - Sebastian Hupfauf
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, A-6020 Innsbruck, Austria.
| | - Anna Arthofer
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, A-6020 Innsbruck, Austria.
| | - Christian Ebner
- Department of Infrastructure, Universität Innsbruck, Technikerstraße 13, A-6020 Innsbruck, Austria.
| | - Wolfgang Rauch
- Department of Infrastructure, Universität Innsbruck, Technikerstraße 13, A-6020 Innsbruck, Austria.
| | - Anke Bockreis
- Department of Infrastructure, Universität Innsbruck, Technikerstraße 13, A-6020 Innsbruck, Austria.
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Galván-Arzola U, Valencia-Vázquez R, Gómez-González R, Alcalá-Rodríguez MM, Loredo-Medrano JÁ, García-Balandrán EE, Rivas-García P. Low-performance diagnosis of covered anaerobic lagoons as a waste management strategy in the intensive dairy industry. ENVIRONMENTAL TECHNOLOGY 2024:1-13. [PMID: 38940278 DOI: 10.1080/09593330.2024.2368688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 05/26/2024] [Indexed: 06/29/2024]
Abstract
Covered anaerobic lagoons (CALs) are Latin America's main livestock waste treatment systems. Mexico has 680 CALs that present low biogas yields (0.05 m3 m-3 digester d-1) and low COD removal rates (< 60%). This work focused on diagnosing CAL´s low performance in dairy farms by determining and analyzing operational parameters. Seven CALs located in the main dairy basin of Mexico were analyzed. The sampling areas for each CAL were the supernatant, the active zone, settled sludge, and digester inlet and outlet. The variation of the process parameter values corroborated that CALs appeared stratified and not working as expected. The sludge zone, comprising 50-58% of total solids content and 1-15% of total CALs volume, showed an elemental compounds content suitable for organic fertilizer (340, 48, and 5 kg t-1 of C, N, and S, respectively). However, this zone contained, at least, 85% of the slowly hydrolysable material; the methanogenic potential was less than 87 mL CH4 g VS-1, and the C/N ratio ranged from 4.9 to 17, outside of the optimal range. The biogas produced did not exceed 60% of methane content and more than 3000 ppm of H2S. The sludge zone significantly influences the lagoon's dynamics since it is a nutrient sink. Furthermore, the lack of agitation is the leading cause for the low energy yield and the low removal of organic matter rate. This work provides valuable information to address the operational problems within the CALs improving our understanding that shall allow proposing reactivation alternatives.
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Affiliation(s)
- Uriel Galván-Arzola
- Facultad de Ciencias Químicas, Departamento de Ingeniería Química, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Mexico
| | - Roberto Valencia-Vázquez
- Maestría en Sistemas Ambientales, División de Estudios de Posgrado e Investigación, Tecnológico Nacional de México, Campus Durango, Durango, México
| | - Ricardo Gómez-González
- Facultad de Ciencias Químicas, Departamento de Ingeniería Química, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Mexico
| | - Mónica María Alcalá-Rodríguez
- Facultad de Ciencias Químicas, Departamento de Ingeniería Química, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Mexico
| | - José Ángel Loredo-Medrano
- Facultad de Ciencias Químicas, Departamento de Ingeniería Química, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Mexico
| | - Ever Efraín García-Balandrán
- Facultad de Ciencias Químicas, Departamento de Ingeniería Química, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Mexico
| | - Pasiano Rivas-García
- Facultad de Ciencias Químicas, Departamento de Ingeniería Química, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Mexico
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Hmaissia A, Bareha Y, Vaneeckhaute C. Correlations and impact of anaerobic digestion operating parameters on the start-up duration: Database construction for robust start-up guidelines. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 359:121068. [PMID: 38728989 DOI: 10.1016/j.jenvman.2024.121068] [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: 01/09/2024] [Revised: 04/17/2024] [Accepted: 04/29/2024] [Indexed: 05/12/2024]
Abstract
Anaerobic digestion (AD) has become a popular technique for organic waste management while offering economic and environmental advantages. As AD becomes increasingly prevalent worldwide, research efforts are primarily focused on optimizing its processes. During the operation of AD systems, the occurrence of unstable events is inevitable. So far, numerous conclusions have been drawn from full and lab-scale studies regarding the driving factors of start-up perturbations. However, the lack of standardized practices reported in start-up studies raises concerns about the comparability and reliability of obtained data. This study aims to develop a knowledge database and investigate the possibility of applying machine learning techniques on experimentation-extracted data to assist start-up planning and monitoring. Thus, a standardized database referencing 75 cases of start-up of one-stage wet continuously-stirred tank reactors (CSTR) processing agricultural, industrial, or municipal organic effluent in mono-digestion from 31 studies was constructed. 10 % of the total observations included in this database concern failed start-up experiments. Then, correlations between the parameters and their impacts on the start-up duration were studied using multivariate analysis and a model-based ranking methodology. Insights into trends of choices were highlighted through the correlation analysis of the database. As such, scenarios favoring short start-up duration were found to involve relatively low retention times (average initial and final hydraulic retention times, (HRTi) and (HRTf) of 26.25 and 20.6 days, respectively), high mean organic loading rates (average OLRmean of 5.24 g VS·d-1·L -1) and the processing of highly fermentable substrates (average feed volatile solids (VSfeed) of 81.35 g L-1). The model-based ranking of AD parameters demonstrated that the HRTf, the VSfeed, and the target temperature (Tf) have the strongest impact on the start-up duration, receiving the highest relative scores among the evaluated AD parameters. The database could serve as a reference for comparison purposes of future start-up studies allowing the identification of factors that should be closely controlled.
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Affiliation(s)
- Amal Hmaissia
- BioEngine Research Team on Green Process Engineering and Biorefineries, Chemical Engineering Department, Université Laval, Pavillon Adrien-Pouliot 1065, av. de la Médecine, Québec, QC, Canada; CentrEau, Centre de Recherche sur l'eau, Université Laval, 1065 Avenue de la Médecine, Québec, QC, G1V 0A6, Canada.
| | - Younes Bareha
- BioEngine Research Team on Green Process Engineering and Biorefineries, Chemical Engineering Department, Université Laval, Pavillon Adrien-Pouliot 1065, av. de la Médecine, Québec, QC, Canada; CentrEau, Centre de Recherche sur l'eau, Université Laval, 1065 Avenue de la Médecine, Québec, QC, G1V 0A6, Canada.
| | - Céline Vaneeckhaute
- BioEngine Research Team on Green Process Engineering and Biorefineries, Chemical Engineering Department, Université Laval, Pavillon Adrien-Pouliot 1065, av. de la Médecine, Québec, QC, Canada; CentrEau, Centre de Recherche sur l'eau, Université Laval, 1065 Avenue de la Médecine, Québec, QC, G1V 0A6, Canada.
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Gao Q, Li L, Wang K, Zhao Q. Mass Transfer Enhancement in High-Solids Anaerobic Digestion of Organic Fraction of Municipal Solid Wastes: A Review. Bioengineering (Basel) 2023; 10:1084. [PMID: 37760186 PMCID: PMC10525600 DOI: 10.3390/bioengineering10091084] [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: 07/31/2023] [Revised: 09/02/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
The increasing global population and urbanization have led to a pressing need for effective solutions to manage the organic fraction of municipal solid waste (OFMSW). High-solids anaerobic digestion (HS-AD) has garnered attention as a sustainable technology that offers reduced water demand and energy consumption, and an increased biogas production rate. However, challenges such as rheology complexities and slow mass transfer hinder its widespread application. To address these limitations, this review emphasizes the importance of process optimization and the mass transfer enhancement of HS-AD, and summarizes various strategies for enhancing mass transfer in the field of HS-AD for the OFMSW, including substrate pretreatments, mixing strategies, and the addition of biochar. Additionally, the incorporation of innovative reactor designs, substrate pretreatment, the use of advanced modeling and simulation techniques, and the novel conductive materials need to be investigated in future studies to promote a better coupling between mass transfer and methane production. This review provides support and guidance to promote HS-AD technology as a more viable solution for sustainable waste management and resource recovery.
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Affiliation(s)
| | | | | | - Qingliang Zhao
- State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, China
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5
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Leite WRM, Scandolara Magnus B, Moraes BABD, Kato MT, Florencio L, Costa RHRD, Belli Filho P. Mesophilic anaerobic digestion of waste activated sludge in an intermittent mixing reactor: Effect of hydraulic retention time and organic loading rate. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 338:117839. [PMID: 37003223 DOI: 10.1016/j.jenvman.2023.117839] [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: 12/21/2022] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 06/19/2023]
Abstract
An anaerobic digester was operated at mesophilic temperature and with intermittent mixing conditions to treat waste activated sludge. The organic loading rate (OLR) was increased by decreasing the hydraulic retention time (HRT), and the effect on process performance, digestate characteristics and inactivation of pathogens was investigated. The removal efficiency of total volatile solids (TVS) was also measured by biogas formation. The HRT varied from 50 to 7 days, corresponding to OLR from 0.38 to 2.31 kgTVS.m-3.d-1. The acidity/alkalinity ratio remained within stable limits (lower than 0.6) at 50-, 25- and 17-day HRT; due to an imbalance between the production and consumption of volatile fatty acids, the ratio increased to 0.7 ± 0.2 at HRT of 9 days and 7 days. The highest TVS removal efficiencies were 16, 12 and 9%, which were obtained at 50-, 25- and 17 day-HRT, respectively. Intermittent mixing provided solids sedimentation greater than 30% for almost all HRT tested. The highest methane yields (0.10-0.05 m3.kgTVSfed-1.d-1) were obtained when the reactor was operated at a higher HRT (50-17 days). At lower HRT, methanogenic reactions were likely limited. Zinc and copper were the main heavy metals found in the digestate, while the most probable number (MPN) of coliform bacteria remained below 106 MPN.g TVS-1. Neither Salmonella nor viable Ascaris eggs were found in the digestate. In general, increasing the OLR by decreasing the HRT to 17 days under intermittent mixing conditions provided an attractive alternative to treat sewage sludge despite some limitations due to biogas and methane yields.
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Affiliation(s)
- Wanderli Rogério Moreira Leite
- Federal University of Pernambuco, Department of Civil and Environmental Engineering, Cidade Universitária, CEP 50670-901, Recife, PE, Brazil.
| | - Bruna Scandolara Magnus
- Federal University of Pernambuco, Department of Civil and Environmental Engineering, Cidade Universitária, CEP 50670-901, Recife, PE, Brazil.
| | | | - Mario Takayuki Kato
- Federal University of Pernambuco, Department of Civil and Environmental Engineering, Cidade Universitária, CEP 50670-901, Recife, PE, Brazil.
| | - Lourdinha Florencio
- Federal University of Pernambuco, Department of Civil and Environmental Engineering, Cidade Universitária, CEP 50670-901, Recife, PE, Brazil.
| | - Rejane Helena Ribeiro da Costa
- Federal University of Santa Catarina, Department of Sanitary and Environmental Engineering, Campus Universitário Trindade, CEP 88.010-970, Florianópolis, SC, Brazil.
| | - Paulo Belli Filho
- Federal University of Santa Catarina, Department of Sanitary and Environmental Engineering, Campus Universitário Trindade, CEP 88.010-970, Florianópolis, SC, Brazil.
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Ferreira TB, Passos F, Leite de Souza C. Long-term operation of anaerobic digestion of food waste under simplified conditions: effect on reactor performance. ENVIRONMENTAL TECHNOLOGY 2023; 44:316-325. [PMID: 34407731 DOI: 10.1080/09593330.2021.1970819] [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: 04/03/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Anaerobic digestion under simplified conditions can contribute to food waste decentralised management. However, there is an absence of knowledge on the effect of long-term operation under these conditions. This study aimed to evaluate the operational conditions of an anaerobic reactor treating food waste after long-term operation without temperature control and low-intensity mixing. For this, a demonstration-scale reactor (18.8 m3) was operated for 160 days, while stability parameters were used to control the applied organic loading rate (OLR). Stability parameters indicated that the reactor was operated at stable conditions with an OLR of 0.3 kg VS m-3 d-1, while it was overloaded at an OLR of 0.4 kg VS m-3 d-1. This was observed through high value of intermediate and partial alkalinity ratio (IA/PA ratio), 2.5, and low values of bicarbonate alkalinity and pH, 1800 mg CaCO3 L-1 and 6.8, respectively. Moreover, there was a change in the concentration of intermediated metabolites, with a higher content of propionate and acetate, 1080 and 3775 mg L-1, respectively. Consequently, the methane production rate was decreased from 0.12 to 0.08 m3 CH4 m-3 d-1 and methane yield from 0.43 to 0.15 m3 CH4 kg VS-1. The reactor instability at a relatively low OLR was most probably due to hydrodynamic factors caused by the accumulation of recalcitrant material. Therefore, this material reduced the reactor performance and requires attention for a sustainable long-term operation.
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Affiliation(s)
- Tiago B Ferreira
- Department of Sanitary and Environmental Engineering, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Fabiana Passos
- Department of Sanitary and Environmental Engineering, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Cláudio Leite de Souza
- Department of Sanitary and Environmental Engineering, Federal University of Minas Gerais, Belo Horizonte, Brazil
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7
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Li L, Wang K, Sun Z, Zhao Q, Zhou H, Gao Q, Jiang J, Mei W. Effect of optimized intermittent mixing during high-solids anaerobic co-digestion of food waste and sewage sludge: Simulation, performance, and mechanisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 842:156882. [PMID: 35753448 DOI: 10.1016/j.scitotenv.2022.156882] [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: 04/15/2022] [Revised: 06/01/2022] [Accepted: 06/18/2022] [Indexed: 06/15/2023]
Abstract
Inadequate mixing has been proven to be a major cause of anaerobic digester failure. This study revealed the mechanism of mixing intervals on high-solids anaerobic co-digestion (HS-AcoD) of food waste (FW) and sewage sludge (SS). Optimized intermittent mixing time (15 min/h) was determined through computational fluid dynamics (CFD) simulation. Experimental results indicated that the simulated intermittent mixing could shorten digestion time and increase cumulative methane output (366.8 mL/gVS) compared with continuous mixing and unmixing. Mixing could considerably accelerate substrate solubilization and hydrolysis. Maximum rates of acidogenesis (53.35 %) and methanogenesis (49.41 %) were observed with an optimized intermittent mixing (15 min/h). Vigorous mixing induced apoptosis and disrupted syntrophic metabolism, whereas intermittent mixing promoted the syntrophic metabolism between Syntrophomonas and Methanobacterium, and led to an enrichment of genes involved in acidogenic and methanogenic pathways. These findings have important implications for the development of an optimized intermittent mixing strategy for maximizing HS-AcoD efficiency of FW and SS.
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Affiliation(s)
- Lili Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Kun Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Zhijian Sun
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qingliang Zhao
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Huimin Zhou
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qingwei Gao
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Junqiu Jiang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Wangyang Mei
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
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Zhang L, Li F, Tsui TH, Yoh K, Sun J, Loh KC, Wang CH, Dai Y, Tong YW. Microbial succession analysis reveals the significance of restoring functional microorganisms during rescue of failed anaerobic digesters by bioaugmentation of nano-biochar-amended digestate. BIORESOURCE TECHNOLOGY 2022; 352:127102. [PMID: 35367604 DOI: 10.1016/j.biortech.2022.127102] [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: 02/21/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 06/14/2023]
Abstract
Nano-biochar application was investigated for anaerobic digestion of orange peel waste. The application for methane production focused on the optimization of biochar feedstock, rescue of failed digesters, and microbial succession analysis. It showed that sewage sludge (SS) derived biochar had the highest performance enhancement among the different feedstocks, which could be ascribed to the improvement of electron transfer, interspecies hydrogen transfer, and supply of trace elements. Subsequently, nano SS biochar-amended digestate was evaluated for rescuing failed digesters, and the experimental results indicated its positive roles through gradual bioaugmentation operation. The dynamic analysis of microbial succession indicated the successful application was through the mechanism of restoring partially the functional microbial communities. The major reconstruction of functional microorganisms included bacteria phyla Hydrogenispora (24.5%) and Defluviitoga (18.8%) as well as methanogenic genera of Methanosarcina (41.5%) and Methanobacterium (27.3%). These findings would contribute to rescuing failed anaerobic digesters by bioaugmentation with biochar-amended digestate.
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Affiliation(s)
- Le Zhang
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, Singapore 138602, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore 138602, Singapore
| | - Fanghua Li
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, Singapore 138602, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore 138602, Singapore; State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - To-Hung Tsui
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, Singapore 138602, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore 138602, Singapore
| | - Kato Yoh
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore
| | - Jiachen Sun
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore
| | - Kai-Chee Loh
- Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore
| | - Chi-Hwa Wang
- Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore
| | - Yanjun Dai
- Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore 138602, Singapore; School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Yen Wah Tong
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, Singapore 138602, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
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Recovery of Household Waste by Generation of Biogas as Energy and Compost as Bio-Fertilizer—A Review. Processes (Basel) 2021. [DOI: 10.3390/pr10010081] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Nowadays, organic waste and especially household waste represents a significant global issue due to population growth. The anaerobic digestion (AD) process is an essential operation contributing powerfully to the valorization of organic waste including food waste in terms of renewable energy generation (biogas) and the rich-nutrient residue that can be utilized as bio-fertilizer. Thus, this process (AD) allows for good recovery of household waste by generating biogas and compost. However, the AD operation has been affected by several key factors. In this paper, we aim to involve different critical parameters influencing the AD process, including temperature, pH, organic loading rate (OLR), carbon to nitrogen ratio (C/N), and total solid content (TS(%)). Further, the paper highlights the inhibition caused by the excessive accumulation of volatile fatty acids (VFAs) and ammoniac, which exhibits the positive effects of co-digestion, pretreatment methods, and mixing techniques for maintaining process stability and enhancing biogas production. We analyze some current mathematical models explored in the literature, such as distinct generic, non-structural, combined, and kinetic first-order models. Finally, the study discusses challenges, provides some possible solutions, and a future perspective that promises to be a highly useful resource for researchers working in the field of household waste recovery for the generation of biogas.
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Abstract
In a lab-scale bioreactor system, (20 L of effective volume in our study) controlling a constant temperature inside bioreactor with a total volume 25 L is a simple process, whereas it is a complicated process in the actual full-scale system. There might exist a localized temperature difference inside the reactor, affecting bioenergy yield. In the present work, the temperature at the middle layer of bioreactor was controlled at 35 °C, while the temperature at top and bottom of bioreactor was controlled at 35 ± 0.1, ±1.5, ±3.0, and ±5.0 °C. The H2 yield of 1.50 mol H2/mol hexoseadded was achieved at ±0.1 and ±1.5 °C, while it dropped to 1.27 and 0.98 mol H2/mol hexoseadded at ±3.0 and ±5.0 °C, respectively, with an increased lactate production. Then, the reactor with automatic agitation speed control was operated. The agitation speed was 10 rpm (for 22 h) under small temperature difference (<±1.5 °C), while it increased to 100 rpm (for 2 h) when the temperature difference between top and bottom of reactor became larger than ±1.5 °C. Such an operation strategy helped to save 28% of energy requirement for agitation while producing a similar amount of H2. This work contributes to facilitating the upscaling of the dark fermentation process, where appropriate agitation speed can be controlled based on the temperature difference inside the reactor.
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11
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Khalil CA, Eraky MT, Ghanimeh S. Localized mixing of anaerobic plug flow reactors. WATER RESEARCH 2021; 204:117588. [PMID: 34481287 DOI: 10.1016/j.watres.2021.117588] [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: 02/12/2021] [Revised: 08/06/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
An innovative localized-mixing concept was tested in an Anaerobic Plug Flow Reactor (AnPFR) treating Food Waste (FW) mixed with municipal Wastewater (WW). The proposed concept consists of placing propellers along the shaft of the AnPFR at key points that represent the mid-region of each of the anaerobic digestion stages: hydrolysis, acidogenesis, and methanogenesis. First, the need for and efficiency of localized mixing (the new concept suggested by the authors) were investigated. While the main benefit of localized mixing is the reduction of energy demand associated with (conventional) uniform mixing (i.e., throughout the longitudinal axis), the system can also benefit from synergetic reactions in non-mixed zones. In fact, at a Total Solid (TS) content of 15% (Organic Loading Rate (OLR) of 4.2 g VS.L - 1.d - 1) and a Hydraulic Retention Time (HRT) of 28 days, the mixing pattern was sufficient to maintain stable operation, with high removal rates (up to 96% of solids) and high biogas generation (1128 ± 55 ml.g VSfed-1, of which 68.9% consisted of CH4); but when mixing was halted, the system's performance deteriorated. Second, the loading capacity of the locally-mixed AnPFR was investigated by subjecting it to different TS content (10%, 15%, 20%, and 22.5%, corresponding to OLRs of 2.8, 4.2, 6.3, and 7.9 g VS.L - 1.d - 1, respectively) while operating under the same HRT. It was found that the system can adequately sustain a feed with a maximum TS of 20% while achieving removal rates up to 92% for solids and a CH4 yield of 613 ml.g VSfed-1. The digester was simulated using computational fluid dynamics. The outputs revealed: (1) highest radial mixing at the center of the methanogenesis zone where the propeller is located and (2) low longitudinal mixing before and after the propeller of the methanogenesis stage, implying the presence of sedimentation zones that was visually verified. The former is assumed to favor better dispersion of inhibitors and improved stability, while the latter is expected to provide stagnant areas for enhanced biochemical synergies.
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Affiliation(s)
- Charbel Abou Khalil
- Center for Natural Resources, Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Mohamed T Eraky
- Department Mechanical and Aerospace Engineering, Rutgers-New Brunswick, USA, NJ 08854
| | - Sophia Ghanimeh
- Department Civil and Environmental Engineering, Notre Dame University-Louaize, Lebanon.
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12
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Mao L, Tsui TH, Zhang J, Dai Y, Tong YW. Mixing effects on decentralized high-solid digester for horticultural waste: Startup, operation and sensitive microorganisms. BIORESOURCE TECHNOLOGY 2021; 333:125216. [PMID: 33933829 DOI: 10.1016/j.biortech.2021.125216] [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: 03/06/2021] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
This work studied the use of a horizontal high-solid digester for the decentralized anaerobic treatment of horticultural waste (fallen leaves), where the effect of intermittent mixing by a modified double helical ribbon impeller was investigated. Before experimental verification, the flow pattern and theoretical mixing time were first characterized by CFD simulation. Subsequently, three mixing time intervals (i.e., 3 min/3 hr; 18 min/3 hr; 108 min/3 hr) and one control setup (i.e., without mixing) were compared for their performance during start-up and semi-continuous operation. It was found that minimal mixing was necessary for an efficient digester's start-up but increased mixing intensity for semi-continuous operation. The results were further interpreted by correlating the digester performance and microbial communities. Those microorganisms sensitive to increased mixing intensity were highlighted and analysed.
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Affiliation(s)
- Liwei Mao
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore
| | - To-Hung Tsui
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore 138602, Singapore
| | - Jingxin Zhang
- China-UK Low Carbon College, Shanghai Jiaotong University, 3 YinlianRoad, Shanghai 201306, China
| | - Yanjun Dai
- School of Mechanical Engineering, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Yen Wah Tong
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore.
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13
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Yang P, Peng Y, Tan H, Liu H, Wu D, Wang X, Li L, Peng X. Foaming mechanisms and control strategies during the anaerobic digestion of organic waste: A critical review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 779:146531. [PMID: 34030228 DOI: 10.1016/j.scitotenv.2021.146531] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 03/11/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
Foaming is a problem that affects the efficient and stable operation of the anaerobic digestion process. Characterizing foaming mechanisms and developing early warning and foaming control methods is thus critically important. This review summarizes the correlation of process parameters, state parameters, and microbial communities with foaming in anaerobic digesters; discusses the applicability of the above-mentioned multi-scale parameters and foaming potential evaluation methods for the prediction of foaming risk; and introduces the principles and practical applications of antifoaming and defoaming methods. Multiple causes of foaming in anaerobic digestion systems have been identified, but a generalizable foaming mechanism has yet to be described. Further study of the correlation between extracellular polymeric substances and soluble microbial products and foaming may provide new insights into foaming mechanisms. Monitoring the foaming potential (including the volume expansion potential) is an effective approach for estimating the risk of foaming. An in-situ monitoring system for determining the foaming potential in anaerobic digestion sites could provide an early warning of foaming risk. Antifoaming methods based on operating parameter management and process regulation help prevent foaming from the source, and biological defoaming methods are highly targeted and efficient, which is a promising research direction. Clarifying foaming mechanisms will aid the development of active antifoaming methods and efficient biological defoaming methods.
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Affiliation(s)
- Pingjin Yang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Yun Peng
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Hanyue Tan
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Hengyi Liu
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Di Wu
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Xiaoming Wang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Lei Li
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China.
| | - Xuya Peng
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
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14
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Ohnmacht B, Lemmer A, Oechsner H, Kress P. Demand-oriented biogas production and biogas storage in digestate by flexibly feeding a full-scale biogas plant. BIORESOURCE TECHNOLOGY 2021; 332:125099. [PMID: 33862386 DOI: 10.1016/j.biortech.2021.125099] [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: 01/31/2021] [Revised: 03/24/2021] [Accepted: 03/26/2021] [Indexed: 06/12/2023]
Abstract
This work studied the demand-oriented biogas production and the biogas storage in digestate by flexibly feeding a full-scale research biogas plant. The investigated continuous stirred tank reactor (CSTR) was equipped with a fast-moving submersible motor mixer and a slow-moving inclined shaft agitator. A model for the biogas storage in digestate was introduced and tested in full scale using temporally highly resolved volume flow measurements. An increase in mixing time led to a faster biogas production: A two to five hours reduction of the time to reach the maximum biogas production after feeding occurred in our experiments. However, no influence of the rheology and of the mixing regime on the methane yield could be derived from the measurements. Further, a 30% reduction of the stored biogas in the digestate occurred when the viscosity was lowered by 66%. This knowledge can be used to enhance the existing biogas formation models.
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Affiliation(s)
- Benjamin Ohnmacht
- University of Hohenheim, State Institute of Agricultural Engineering and Bioenergy, Garbenstr. 9, Stuttgart 70599, Germany.
| | - Andreas Lemmer
- University of Hohenheim, State Institute of Agricultural Engineering and Bioenergy, Garbenstr. 9, Stuttgart 70599, Germany
| | - Hans Oechsner
- University of Hohenheim, State Institute of Agricultural Engineering and Bioenergy, Garbenstr. 9, Stuttgart 70599, Germany
| | - Philipp Kress
- University of Hohenheim, State Institute of Agricultural Engineering and Bioenergy, Garbenstr. 9, Stuttgart 70599, Germany
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15
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Postawa K, Szczygieł J, Wrzesińska-Jędrusiak E, Klimek K, Kułażyński M. The pump-mixed anaerobic digestion of pig slurry: new technology and mathematical modeling. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 123:111-119. [PMID: 33581640 DOI: 10.1016/j.wasman.2021.01.016] [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: 08/05/2020] [Revised: 12/14/2020] [Accepted: 01/07/2021] [Indexed: 06/12/2023]
Abstract
Biogas production is a relatively novel and developing branch of the renewable fuel sector, which allows agricultural waste, and more, to be used as a feedstock. New technologies have been integrated into the process to improve its efficiency. In this study, a pump-mixed anaerobic digestion concept is considered for both experimental and modeling approaches. The experiment included a total of nine configurations with the same geometry (140 dm3 of total reactor volume) but different hydraulic retention times and mixing intervals. The measurements were used to create and optimize a mathematical model. The complete-stirring assumption, which underlies most anaerobic digestion (AD) simulations, is no longer valid in this case. Thus, the novel concept is developed by assuming that the liquid phase is split into three separate sections, which approximates the concentration gradient in a real reactor. This method allows partial differential equations to be avoided, which could potentially affect the calculation efficiency. The final mean accuracy of the model in the tested range was estimated to be 86.60% while, in selected parts of the scope, was close to 90%. The pump-mixed anaerobic digestion technique in the experiment achieved high production performance (above 8 dm3 of product per 1 dm3 of feedstock) while maintaining a high methane content (approximately 65%). The comparison between the reactor stirred by an impeller, and the pump-mixed, indicated that the proposed configuration ensures better production stability. Additionally, it was possible to achieve a higher biogas production rate with the same feedstock concentration.
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Affiliation(s)
- Karol Postawa
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | - Jerzy Szczygieł
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Edyta Wrzesińska-Jędrusiak
- Department of Renewable Energy Sources, Institute of Technology and Life Sciences, Falenty, Al. Hrabska 3, 05-090 Raszyn, Poland
| | - Kamila Klimek
- Department of Applied Mathematics and Informatics, University of Life Sciences in Lublin, Gleboka 28, 20-612 Lublin, Poland
| | - Marek Kułażyński
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
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16
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Abstract
Agitated vessels (or mechanically stirred reactors) are heat exchange devices that are most widely used in many chemical and biochemical process industries, such as anaerobic digestion process. The mixing and heat transfer performances in these vessels are of crucial importance for increasing the energy efficiency in both batch and continuous processes. In this paper, a series of experiments were conducted to investigate heat transfer performance in agitated vessels for various configurations. In fact, this study examines the effects of heat transfer geometry (wall jacket and helical coils), heating power, and stirring speed, on the heating performance of two stirred fluids—water alone and a mixture of water and food waste. The experiments were conducted using a jacketed insulation tank with a helical coil and a propeller agitator. In each experiment, a transient method, based on measuring the temperature dependency on time, and solving the unsteady enthalpy balance, was used to determine the overall heat transfer coefficients between the agitated fluid and the heating surface. Finally, an extensive analysis of the reduced data was conducted based on temperature, heating time, heat transfer rate, heat transfer coefficient, and thermal resistance. The main finding was that the presence of food waste in agitated vessels reduces the heat rate of the agitated fluid with an average of 18.13% and 49.51%, respectively, for the case of JHX and CHX, and creates additional fouling, which further limits the heat transfer.
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17
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Qiu N, Wang P, Si Q, Pettang WE, Yuan S. Scale process effect on the power consumption characteristics of a novel curved Rushton turbine within a reactor vessel. Chem Eng Res Des 2021. [DOI: 10.1016/j.cherd.2020.11.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Wang H, Larson RA, Borchardt M, Spencer S. Effect of mixing duration on biogas production and methanogen distribution in an anaerobic digester. ENVIRONMENTAL TECHNOLOGY 2021; 42:93-99. [PMID: 31159681 DOI: 10.1080/09593330.2019.1621951] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 05/09/2019] [Indexed: 06/09/2023]
Abstract
Mixing has been shown to have effect on biogas production in anaerobic digestion systems. To further examine this impact, a study was designed to evaluate nearly continuous mixing (mixing for 15 min followed by no mixing for 15 min, CON), intermediate mixing (mixing for 15 min followed by no mixing for 45 min, INT) and no mixing (unmixed, NO) on biogas production in three 208 L pilot-scale tank reactors. The experiments were conducted in triplicates at a controlled temperature of 37 ± 1°C, with a total solids percentage of 5%, a hydraulic retention time (HRT) of 21 days, and an organic loading rate (OLR) of 2 kg VS m-3 d- 1. Digesters with NO mixing had greater solids build up in the bottom quarter of the digester after four weeks' retention time. The methane percentage in biogas produced from digesters with INT and CON mixing were 63% and 62%, respectively, which were 4% and 5% higher than that from digesters with NO mixing (58%). The specific methane yield for digesters with NO, INT and CON mixing was 1.15, 1.15, and 1.49 m3-methane per kg-VS destroyed, however, those differences were not statistically significant (p > 0.05). Digesters had the least amount of Methanosarcinales of the methanogens measured under all treatments. However, the Methanosarcinales, Methanosarcinaceae, Methanomicrobiales, and the total amount of methanogens were less in digesters with INT mixing compared to NO and CON mixing treatments.
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Affiliation(s)
- Hui Wang
- Department of Biological Systems Engineering, University of Wisconsin - Madison, Madison, WI, USA
| | - Rebecca A Larson
- Department of Biological Systems Engineering, University of Wisconsin - Madison, Madison, WI, USA
| | - Mark Borchardt
- USDA Agricultural Research Service - Institute for Environmentally Integrated Dairy Management, Marshfield, WI, USA
| | - Susan Spencer
- USDA Agricultural Research Service - Institute for Environmentally Integrated Dairy Management, Marshfield, WI, USA
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19
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Qi WK, Liu LF, Shi Q, Wang C, Li YY, Peng Y. Detailed composition evolution of food waste in an intermittent self-agitation anaerobic digestion baffled reactor. BIORESOURCE TECHNOLOGY 2021; 320:124342. [PMID: 33157439 DOI: 10.1016/j.biortech.2020.124342] [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: 09/09/2020] [Revised: 10/23/2020] [Accepted: 10/24/2020] [Indexed: 06/11/2023]
Abstract
This study used an intermittent self-agitation anaerobic baffled reactor (SA-ABR) to treat food waste. The organic matter and detailed composition evolution were analyzed under continuous operation. The gas production rate was 2.43 ± 0.18 L-Gas/d/L-Re, and the biogas conversion was 0.94 L-Gas/g-TS. The effluent concentration of total chemical oxygen demand (COD) was 22.5 ± 2.44 g/L, and the removal rate of soluble COD was always over 97%. In this study, the removal rates of carbohydrate, protein, and lipids in the SA-ABR treatment were 95%, 60%, and 85%, respectively, and the concentrations were 0.11 g/L, 0.32 g/L, and 0.33 g/L, respectively. The conversion of soluble organic matter was much higher than that of insoluble substrates. The concentration of soluble pollutants was significantly lower than that of pollutants in suspended matter. The treatment of organic matter in the first half of the SA-ABR was 85-100% that of the entire reactor.
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Affiliation(s)
- Wei-Kang Qi
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China; Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China.
| | - Li-Fang Liu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China; Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Qi Shi
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China; Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Cong Wang
- Beijing Drainage Group Co., Ltd., Beijing 100044, China
| | - Yu-You Li
- Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China; Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
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20
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Yang H, Deng L. Using air instead of biogas for mixing and its effect on anaerobic digestion of animal wastewater with high suspended solids. BIORESOURCE TECHNOLOGY 2020; 318:124047. [PMID: 32871320 DOI: 10.1016/j.biortech.2020.124047] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/14/2020] [Accepted: 08/19/2020] [Indexed: 06/11/2023]
Abstract
This study proposed a new mixing method for anaerobic digestion treating animal wastewater using air as gas source of agitation (named "air mixing") and demonstrated its feasibility by comparing with other mixing modes. The results indicated that the methane production for air mixing was increased by 6.4%, 11.9% and 19.6% compared with biogas mixing, mechanical mixing and no mixing. Air mixing improved the mass transfer and the homogeneous mixing time was shortened from 10 min of mechanical mixing to 1.5 min at the same power input. A transient microaerobic environment was created by air mixing, which increased the hydrolysis efficiency by 1.7-11.4% compared with biogas mixing and facilitated VFAs generation and consumption, as well as promoted the syntrophic relationship between facultative bacteria and hydrogenotrophic methanogens. The relative contribution of the improvement of mass transfer and the reaction of microaerobic environment to methane production was 62.9% and 37.1%, respectively.
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Affiliation(s)
- Hongnan Yang
- Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China; Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China
| | - Liangwei Deng
- Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China; Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China.
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21
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Zhang L, Guo B, Mou A, Li R, Liu Y. Blackwater biomethane recovery using a thermophilic upflow anaerobic sludge blanket reactor: Impacts of effluent recirculation on reactor performance. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 274:111157. [PMID: 32805474 DOI: 10.1016/j.jenvman.2020.111157] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 07/03/2020] [Accepted: 07/29/2020] [Indexed: 06/11/2023]
Abstract
Thermophilic anaerobic digestion is a promising process for high-solid blackwater (BW) treatment due to improved hydrolysis rates, high methanogenesis efficiency, and pathogen removal, when compared with mesophilic treatment. In the present work, the effects of effluent recirculation (i.e., mixing) on thermophilic blackwater treatment were studied. A laboratory-scale thermophilic upflow anaerobic sludge blanket reactor was operated with and without effluent recirculation. The methanogenesis efficiency of the BW treatment increased from 45.0 ± 2.9% when effluent recirculation was applied to 56.7 ± 5.5% without effluent recirculation. Without effluent recirculation, the COD accumulation in the bioreactor was reduced from 17.2 to 3.8% and the effluent volatile fatty acids (VFA) concentration was reduced from 0.64 ± 0.18 to 0.15 ± 0.10 g/L. Further, both acetoclastic and hydrogenotrophic methanogenic activity increased from 101.3 ± 10.8 and 93.9 ± 6.1 to 120.4 ± 9.4 and 118.2 ± 13.2 mg CH4-COD/(gVSS⋅d), respectively, after effluent recirculation was discontinued. The predominant methanogens changed from Methanothermobacter (67%) with effluent recirculation to Methanosarcina (62%) without effluent recirculation. As compared to the effluent recirculation conditions, the enhanced biomethane recovery and treatment performance without effluent recirculation can be attributed to the close proximity of bacteria and archaea groups and the reduced VFA accumulation. Predicted functional gene comparison showed higher prevalence of function for intermediate metabolite transportation (transporters, ATP-binding cassette (ABC) transporters, and two-component system) after discontinuing effluent circulation, which contributed to improved syntrophic propionate oxidation and syntrophic acetate oxidization and enhanced hydrogenotrophic methanogenesis.
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Affiliation(s)
- Lei Zhang
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada
| | - Bing Guo
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada
| | - Anqi Mou
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada
| | - Ran Li
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada; College of Petroleum Engineering, Xi'an Shiyou University, Xi'an, 710065, Shaanxi Province, China
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada.
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22
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Zhang Z, Zhang H, Li Y, Lu C, Zhu S, He C, Ai F, Zhang Q. Investigation of the interaction between lighting and mixing applied during the photo-fermentation biohydrogen production process from agricultural waste. BIORESOURCE TECHNOLOGY 2020; 312:123570. [PMID: 32470828 DOI: 10.1016/j.biortech.2020.123570] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 05/19/2020] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
To better clarify the effect of lighting and mixing on the hydrogen production from agricultural waste, experiments under diverse constant and dynamic light intensities and mixing speeds were conducted. Cumulative hydrogen yield, hydrogen production rate, OD660, pH, reducing sugar concentration were monitored. Results showed that mixing had positive effects on high substrate concentration. The interaction between lighting and mixing was drawn. Higher light intensity (7000 Lux) was suitable for hydrogen production under mixing. Higher light intensity with higher mixing speed (150 RPM) showed the highest cumulative hydrogen yield of 78.1 mL/g TS. Different periods of hydrogen production process required distinct lighting and mixing. Combined with Gompertz model, dynamic lighting and mixing strategies were discussed. Dynamic light intensity (4000-7000-4000 Lux) accompanied with dynamic mixing speed (50-150-50 RPM) was the optimal condition for PFHP. Highest hydrogen yield of 84.7 mL/g TS and highest light conversion efficiency of 36.32% were obtained.
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Affiliation(s)
- Zhiping Zhang
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy of Ministry of Agriculture and Rural Affairs, College of Mechanical & Electrical Engineering, Henan Agricultural University, Zhengzhou 450002, China
| | - Haorui Zhang
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy of Ministry of Agriculture and Rural Affairs, College of Mechanical & Electrical Engineering, Henan Agricultural University, Zhengzhou 450002, China
| | - Yameng Li
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy of Ministry of Agriculture and Rural Affairs, College of Mechanical & Electrical Engineering, Henan Agricultural University, Zhengzhou 450002, China
| | - Chaoyang Lu
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy of Ministry of Agriculture and Rural Affairs, College of Mechanical & Electrical Engineering, Henan Agricultural University, Zhengzhou 450002, China
| | - Shengnan Zhu
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy of Ministry of Agriculture and Rural Affairs, College of Mechanical & Electrical Engineering, Henan Agricultural University, Zhengzhou 450002, China
| | - Chao He
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy of Ministry of Agriculture and Rural Affairs, College of Mechanical & Electrical Engineering, Henan Agricultural University, Zhengzhou 450002, China
| | - Fuke Ai
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy of Ministry of Agriculture and Rural Affairs, College of Mechanical & Electrical Engineering, Henan Agricultural University, Zhengzhou 450002, China
| | - Quanguo Zhang
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy of Ministry of Agriculture and Rural Affairs, College of Mechanical & Electrical Engineering, Henan Agricultural University, Zhengzhou 450002, China.
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23
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Abstract
The biogas production technology has improved over the last years for the aim of reducing the costs of the process, increasing the biogas yields, and minimizing the greenhouse gas emissions. To obtain a stable and efficient biogas production, there are several design considerations and operational parameters to be taken into account. Besides, adapting the process to unanticipated conditions can be achieved by adequate monitoring of various operational parameters. This paper reviews the research that has been conducted over the last years. This review paper summarizes the developments in biogas design and operation, while highlighting the main factors that affect the efficiency of the anaerobic digestion process. The study’s outcomes revealed that the optimum operational values of the main parameters may vary from one biogas plant to another. Additionally, the negative conditions that should be avoided while operating a biogas plant were identified.
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24
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How Different Are Manometric, Gravimetric, and Automated Volumetric BMP Results? WATER 2020. [DOI: 10.3390/w12061839] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The objectives of this study were to: (1) quantify differences in biochemical methane potential (BMP) measured using three measurement methods, including two popular methods (a commercial automated system (AMPTS II) and manual manometric) and one newer method (gravimetric), and (2) assess the importance of the mixing position in the measurement sequence. Powdered microcrystalline cellulose was used as the substrate in simultaneous tests. All methods gave similar results (<8% difference in the mean BMP) and were reasonably accurate (recovery of 80–86% of the theoretical maximum BMP). Manometric BMP values were consistently lower than gravimetric by 4–5%. Precision was lower for the automated method (relative standard deviation (RSD) of about 7%) than for the manual methods (RSD about 1–3%). Mixing after biogas measurement resulted in 3% higher BMP for both manual methods than mixing before, due to the lower measured CH4 production from blanks. This effect may be linked to a fraction of CH4 that remains dissolved or even as attached bubbles, and suggests that mixing before measurement is preferable. The automated volumetric and gravimetric methods (mode 2) gave very similar mean BMP values (1% different). However, kinetic analysis showed that methane production was faster with the automated volumetric method. This could come from an error in the estimation of the CH4 production rate for the automated method, or an increase in the degradation rate due to better mixing. Both automatic volumetric and manual gravimetric measurements met current validation criteria for mean cellulose BMP, but the RSD from the automated system exceeded the limit.
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25
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Xu Y, Lu Y, Zheng L, Wang Z, Dai X. Perspective on enhancing the anaerobic digestion of waste activated sludge. JOURNAL OF HAZARDOUS MATERIALS 2020; 389:121847. [PMID: 31843416 DOI: 10.1016/j.jhazmat.2019.121847] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 12/05/2019] [Accepted: 12/06/2019] [Indexed: 05/25/2023]
Abstract
Anaerobic digestion (AD) of waste activated sludge (WAS) is an important bio-energy strategy that has been hindered by low conversion efficiency. This paper presents a comprehensive review of research on the sludge's property and enhancing AD of WAS, and proposes two perspectives of material structure and microbial activity on improving AD efficiency. In the first part of this review, the key principle problems for hindering AD efficiency are identified based on the concept of AD. Then, the possibility that the complex microstructure and composition of WAS are responsible for poor biodegradability is considered and main methods for enhancing AD are summarized. In the third part, according to the published works, the main knowledge gaps in research are recognized as the identification and specific activity adjustment of functional microbes, the understanding of key constituents of WAS and their interactions, the deciphering of complex structure of sludge organic substance, and the revealing of relationships between complex nature of WAS and biodegradability. Further discussions reveal that to enhance AD more studies should be centered on the sludge's structure and properties in future. However, this review is expected to provide the clear and accurate research directions for enhancing AD efficiency of WAS.
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Affiliation(s)
- Ying Xu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Yiqing Lu
- Tongji Architectural Design (Group) Co., Ltd., Shanghai, 200092, China
| | - Linke Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Zhiwei Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
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Maurus K, Ahmed S, Kazda M. Beneficial effects of intermittent feedstock management on biogas and methane production. BIORESOURCE TECHNOLOGY 2020; 304:123004. [PMID: 32087544 DOI: 10.1016/j.biortech.2020.123004] [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: 12/16/2019] [Revised: 02/07/2020] [Accepted: 02/08/2020] [Indexed: 06/10/2023]
Abstract
Intermittent supply of easily degradable carbohydrates can be used for on-demand biogas production. The study tested the effects of splitting feeding portions of sugar beet silage (S) on biogas production rates and total yield, respectively and if methane production rates follow those ones of biogas. Four experimental AD reactors were operated for 117 days at organic loading rates of 2.0 kgVS m-3 d-1 and VS ratios of maize silage (M) to S of 3:1. While M was supplied hourly (h0-h12), reactors differed only regarding the intermittent S supply, provided at once (h0), twice (h0, h1) and three times (h0, h1, h2) per twelve-hour observation period. Biogas and methane production rates rose simultaneously after S supply and lasted depending on S intakes. Biogas and methane yields were significantly increased at S given once and twice per period. Appropriate feedstock management can thus influence production rates and increase biogas and methane yields.
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Affiliation(s)
- Kerstin Maurus
- Ulm University, Institute of Systematic Botany and Ecology, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | - Sharif Ahmed
- Ulm University, Institute of Systematic Botany and Ecology, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Marian Kazda
- Ulm University, Institute of Systematic Botany and Ecology, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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Singh B, Szamosi Z, Siménfalvi Z. Impact of mixing intensity and duration on biogas production in an anaerobic digester: a review. Crit Rev Biotechnol 2020; 40:508-521. [DOI: 10.1080/07388551.2020.1731413] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Buta Singh
- Institute of Energy Engineering and Chemical Machinery, University of Miskolc, Miskolc, Hungary
| | - Zoltán Szamosi
- Institute of Energy Engineering and Chemical Machinery, University of Miskolc, Miskolc, Hungary
| | - Zoltán Siménfalvi
- Institute of Energy Engineering and Chemical Machinery, University of Miskolc, Miskolc, Hungary
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28
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Effect of Substrate Concentration on Photo-Fermentation Bio-Hydrogen Production Process from Starch-Rich Agricultural Leftovers under Oscillation. SUSTAINABILITY 2020. [DOI: 10.3390/su12072700] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
China has plenty of starch-rich agricultural leftovers, which can be degraded and further utilized for biogas production. Potato, which has more and more cultivated areas, was taken as a substrate. The pH, OD540, biogas yield, hydrogen yield, biogas production rate, and hydrogen production rate were determined to evaluate the effect of substrate concentration on the photo-fermentation bio-hydrogen production process under an oscillation condition. Results showed that the photo-fermentation period was extended to 264 h under oscillation, which was two times longer than the static condition. It was found that 8 g per 100 mL fermentation broth was the most suitable substrate concentration under oscillation, the cumulative hydrogen yield was 510 mL VS−1, and the hydrogen content was 38.36%.
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29
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A Review on the Fate of Nutrients and Enhancement of Energy Recovery from Rice Straw through Anaerobic Digestion. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10062047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Open field burning and tilling the rice straw (RS) back into the fields causes environmental threats by contributing to the increased greenhouse gas emissions. Energy and nutrient recovery from RS through anaerobic digestion (AD) is an effective solution for its utilization. Although RS has good methane potential, its characteristics make it a difficult substrate for AD. This paper reviews the characteristics of RS, mass balance, and distribution of nutrients into liquid and solid digestate in the AD. The present review also discusses the effect of temperature, co-digestion, mixing, inoculum, organic loading rate, recycling liquid digestate, the addition of trace elements, and their bioavailability on the enhancement of biogas/methane yield in the AD of RS. In addition, the digestion of RS at various scales is also covered in the review.
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30
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Rocamora I, Wagland ST, Villa R, Simpson EW, Fernández O, Bajón-Fernández Y. Dry anaerobic digestion of organic waste: A review of operational parameters and their impact on process performance. BIORESOURCE TECHNOLOGY 2020; 299:122681. [PMID: 31902638 DOI: 10.1016/j.biortech.2019.122681] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 06/10/2023]
Abstract
Dry digestion is a suitable technology for treating organic wastes with varying composition such as the organic fraction of municipal solids waste. Yet, there is a need for further research to overcome some of the disadvantages associated with the high total solids content of the process. Optimisation of inoculum to substrate ratio, feedstock composition and size, liquid recirculation, bed compaction and use of bulking agents are some of the parameters that need further investigation in batch dry anaerobic digestion, to limit localised inhibition effects and avoid process instability. In addition, further attention on the relation between feedstock composition, organic loading rate and mixing regimes is required for continuous dry anaerobic digestion systems. This paper highlights all the areas where knowledge is scarce and value can be added to increase dry anaerobic digestion performance and expansion.
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Affiliation(s)
- Ildefonso Rocamora
- Cranfield University, School of Water, Energy and Environment, United Kingdom
| | - Stuart T Wagland
- Cranfield University, School of Water, Energy and Environment, United Kingdom
| | - Raffaella Villa
- Cranfield University, School of Water, Energy and Environment, United Kingdom; De Montfort University, School of Engineering and Sustainable Development, United Kingdom
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Babaei A, Shayegan J. Effects of temperature and mixing modes on the performance of municipal solid waste anaerobic slurry digester. JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE & ENGINEERING 2019; 17:1077-1084. [PMID: 32030176 PMCID: PMC6985316 DOI: 10.1007/s40201-019-00422-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
PURPOSE Anaerobic digestion is a promising technology for simultaneous treatment of biodegradable organic matter of municipal solid waste (MSW) and production of renewable energy. Mixing modes and temperature have influences on biogas production in anaerobic digesters treating MSW. Therefore, in this study, digester was operated at different modes of mixing and temperatures to obtain design criteria. METHODS The experiments were carried out in a semi-continuous digester. In the first part of the investigation, temperature was set at 25, 28, 31 and 34 °C. During this step, digester content was mixed in an intermittent mode by mechanical mixers. In the second part of the study, mixing condition of the digester was set at various modes: continuous, intermittent (15 min on and 30 min off) and minimal (twice in a batch). RESULTS Digestion with a temperature in this range resulted in biogas yield of 0.23-0.33 m3 biogas/kg VS, with a methane content of 60.2-71.8% in biogas. The methane content and yield decreased with reduction of digestion temperature. However, this reduction was almost negligible from 34 to 31 °C. In addition, in comparison to intermittent mixing, continuous and minimal mixing modes reduced the biogas production by 40% and 50%, respectively. Therefore, in this digester greatest biogas yield of 0.33 ± 0.02 m3 biogas/kg VS were obtained at 34 °C and intermittent mixing mode. CONCLUSIONS Based on the data obtained from this study, temperature in the range of 31-34 °C and intermittent mixing is suggested as a base for design purposes.
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Affiliation(s)
- Azadeh Babaei
- Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran
| | - Jalal Shayegan
- Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran
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32
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Mao L, Zhang J, Dai Y, Tong YW. Effects of mixing time on methane production from anaerobic co-digestion of food waste and chicken manure: Experimental studies and CFD analysis. BIORESOURCE TECHNOLOGY 2019; 294:122177. [PMID: 31563113 DOI: 10.1016/j.biortech.2019.122177] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 09/17/2019] [Accepted: 09/18/2019] [Indexed: 06/10/2023]
Abstract
The relationship between mixing time and methane production was investigated by anaerobically co-digesting food waste (FW) and chicken manure (CM) at four different organic loading rates. The mixing pattern and turbulence intensity obtained from CFD were adopted to evaluate the mixing performance in digesters with different viscosities. The simulated mixing time from CFD was selected as a reference for the first time to analyze the methane yield. The results showed that if the digester was well mixed under intermittent mixing mode with relatively short mixing time, then extending mixing time or changing intermittent mixing to continuous mixing would have no substantial effects on methane production. By contrast, continuously mixed digesters performed better when the intermittent mixing modes cannot make the digester get to a high degree of uniformity. Hence, the simulated mixing time from CFD can be used as a reference to determine the experimental mixing time in different cases.
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Affiliation(s)
- Liwei Mao
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, Singapore 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore
| | - Jingxin Zhang
- China-UK Low Carbon College, Shanghai Jiaotong University, 3 YinlianRoad, Shanghai 201306, China
| | - Yanjun Dai
- School of Mechanical Engineering, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Yen-Wah Tong
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, Singapore 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
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33
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Development of a Modified Plug-Flow Anaerobic Digester for Biogas Production from Animal Manures. ENERGIES 2019. [DOI: 10.3390/en12132628] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Traditional plug-flow anaerobic reactors (PFRs) are characterized by lacking a mixing system and operating at high total solid concentrations, which limits their applicability for several kinds of manures. This paper studies the performance of a novel modified PFR for the treatment of pig manure, characterized by having an internal sludge mixing system by biogas recirculation in the range of 0.270–0.336 m3 m−3 h−1. The influence on the methane yield of four operating parameters (recirculation rate, hydraulic retention time, organic loading rate, and total solids) was evaluated by running four modified PFRs at the pilot scale in mesophilic conditions. While the previous biodegradability of organic matter by biochemical methane potential tests were between 31% and 47% with a methane yield between 125 and 184 LCH4 kgVS−1, the PFRs showed a suitable performance with organic matter degradation between 25% and 51% and a methane yield of up to 374 LCH4 kgVS−1. Operational problems such as solid stratification, foaming, or scum generation were avoided.
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34
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Effect of Mixing Regimes on Cow Manure Digestion in Impeller Mixed, Unmixed and Chinese Dome Digesters. ENERGIES 2019. [DOI: 10.3390/en12132540] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study examines the effect of mixing on the performance of anaerobic digestion of cow manure in Chinese dome digesters (CDDs) at ambient temperatures (27–32 °C) in comparison with impeller mixed digesters (STRs) and unmixed digesters (UMDs) at the laboratory scale. The CDD is a type of household digester used in rural and pre-urban areas of developing countries for cooking. They are mixed by hydraulic variation during gas production and gas use. Six digesters (two of each type) were operated at two different influent total solids (TS) concentration, at a hydraulic retention time (HRT) of 30 days for 319 days. The STRs were mixed at 55 rpm, 10 min/hour; the unmixed digesters were not mixed, and the Chinese dome digesters were mixed once a day releasing the stored biogas under pressure. The reactors exhibited different specific biogas production and treatment efficiencies at steady state conditions. The STR 1 exhibited the highest methane (CH4) production and treatment efficiency (volatile solid (VS) reduction), followed by STR 2. The CDDs performed better (10% more methane) than the UMDs, but less (approx. 8%) compared to STRs. The mixing regime via hydraulic variation in the CDD was limited despite a higher volumetric biogas rate and therefore requires optimization.
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35
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Nguyen LN, Johir MAH, Commault A, Bustamante H, Aurisch R, Lowrie R, Nghiem LD. Impacts of mixing on foaming, methane production, stratification and microbial community in full-scale anaerobic co-digestion process. BIORESOURCE TECHNOLOGY 2019; 281:226-233. [PMID: 30825825 DOI: 10.1016/j.biortech.2019.02.077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/15/2019] [Accepted: 02/16/2019] [Indexed: 06/09/2023]
Abstract
This study investigated the impact of mixing on key factors including foaming, substrate stratification, methane production and microbial community in three full scale anaerobic digesters. Digester foaming was observed at one plant that co-digested sewage sludge and food waste, and was operated without mixing. The lack of mixing led to uneven distribution of total chemical oxygen demand (tCOD) and volatile solid (VS) as well as methane production within the digester. 16S rRNA gene-based community analysis clearly differentiated the microbial community from the top and bottom. By contrast, foaming and substrate stratification were not observed at the other two plants with internal circulation mixing. The abundance of methanogens (Methanomicrobia) at the top was about four times higher than at the bottom, correlating to much higher methane production from the top verified by ex-situ biomethane assay, causing foaming. This result is consistent with foaming potential assessment of digestate samples from the digester.
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Affiliation(s)
- Luong N Nguyen
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia.
| | - Md Abu Hasan Johir
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia
| | - Audrey Commault
- Climate Change Cluster (C3), University of Technology Sydney, NSW 2007, Australia
| | | | | | | | - Long D Nghiem
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia; NTT Institute of Hi-Technology, Nguyen Tat Thanh University, Ho Chi Minh City, Viet Nam
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36
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A Review of the Role of Critical Parameters in the Design and Operation of Biogas Production Plants. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9091915] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Many operating parameters, individually or together, may influence the performance of anaerobic digestion towards biogas or digestate yield and quality maximization. The most preferred method of optimizing an anaerobic digestion plant often relies on how carefully the crucial parameters, such as pH, temperature, organic loading rate, hydraulic retention time, and pressure, are chosen. There is a large amount of literature available on optimization of anaerobic digestion; however, given the continued development and implementation of innovative technologies, together with the introduction of increasingly complex systems, it is necessary to update present knowledge on process parameters and their role on operational ranges and flexibilities in real-life anaerobic digestion system. Accordingly, the present review discusses the importance of the selection of operational parameters in existing technologies and their impact on biogas yield. Notably, the four broad areas of feedstock utilization (substrate, inoculum, codigestion and pretreatment), process condition (pH, temperature, pressure, and reactor design), reactor control (HRT and OLR) and inhibition (Ammonia and VFAs) are covered in this review. In addition, particular emphasis is placed on the most recent innovations that have been or may be implemented in current or future biogas plants.
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Önen S, Nsair A, Kuchta K. Innovative operational strategies for biogas plant including temperature and stirring management. WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2019; 37:237-246. [PMID: 30557120 DOI: 10.1177/0734242x18816800] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Finding the optimum operational conditions (mainly temperature and stirring) inside the fermenters is crucial in the field of anaerobic digestion. This study was conducted to contribute to the research area of anaerobic digestion process optimization and is an example for other biogas plants to improve efficiency. The research aimed at finding the optimum operational conditions in a large-scale biogas plant located in Lower Saxony, Germany, which started operation in 2011. The optimization activities were performed by operating the fermenters under different operational conditions: the temperature inside the fermenters ranged between 40°C and 43°C, while applying several stirring scenarios. These changes led to an increase in specific electricity yield of 11.7% and a decrease in internal energy consumption of 10.4%. The total internal energy consumption of the biogas plant was in the range of 6.3-7.2% (the average monthly internal energy consumption was 6.7% in 2013 and 6.0% in 2014) from their own production, and 28% of this energy consumption was used by the stirrers before optimization. Therefore, finding the optimum operational conditions leads to high energy harvesting and lower internal energy consumption.
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Affiliation(s)
- Senem Önen
- TUHH - Hamburg University of Technology, Institute of Environmental Technology and Energy Economics, Waste Resources Management, Hamburg, Germany
| | - Abdullah Nsair
- TUHH - Hamburg University of Technology, Institute of Environmental Technology and Energy Economics, Waste Resources Management, Hamburg, Germany
| | - Kerstin Kuchta
- TUHH - Hamburg University of Technology, Institute of Environmental Technology and Energy Economics, Waste Resources Management, Hamburg, Germany
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McLeod JD, Othman MZ, Parthasarathy R. Process intensification of anaerobic digestion: Influence on mixing and process performance. BIORESOURCE TECHNOLOGY 2019; 274:533-540. [PMID: 30557827 DOI: 10.1016/j.biortech.2018.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 12/03/2018] [Accepted: 12/06/2018] [Indexed: 05/22/2023]
Abstract
The adoption of process intensification to anaerobic digestion can present significant complications for digester mixing and process performance. This work investigated how increasing the solids concentration of the digester sludge influenced the process at various mixing energy inputs. Based on the results, adequate mixing is defined qualitatively as the input of sufficient energy to mobilize the reactor contents without producing significant regions of inhibitory shear force. However, the quantitative definition is dependent on the solids concentration of the sludge. But, the existing design criterion of specific mixing power input based on fluid volume (W/m3) does not represent it well. Therefore, a new design criterion of specific mixing power input based on total solids in the sludge (W/kgTS) is proposed to achieve maximum biogas production using optimum power input. The relationship has its limitations, but it represents a significant step forward in the design and operation of improved digester mixing systems.
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Affiliation(s)
- James D McLeod
- Chemical & Environmental Engineering, School of Engineering, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia
| | - Maazuza Z Othman
- Chemical & Environmental Engineering, School of Engineering, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia
| | - Rajarathinam Parthasarathy
- Chemical & Environmental Engineering, School of Engineering, RMIT University, 124 La Trobe St., Melbourne, VIC 3000, Australia.
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Kariyama ID, Zhai X, Wu B. Influence of mixing on anaerobic digestion efficiency in stirred tank digesters: A review. WATER RESEARCH 2018; 143:503-517. [PMID: 29990745 DOI: 10.1016/j.watres.2018.06.065] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 06/08/2023]
Abstract
A comprehensive review was carried out on the influence of mixing on anaerobic digestion (AD) efficiency in stirred tank anaerobic digesters. Though traditionally, stirred tank digesters operated as continuous stirred tank reactors (CSTRs), this review revealed that there is no motivation to continue to operate stirred tank anaerobic digesters as CSTRs if AD energy efficiency is to be improved. AD energy production efficiency can be achieved with optimized intermittent mixing. AD efficiency should include an assessment of the net energy production efficiency and should be the criteria in determining the mixing mode, mixing intensity, mixing time and mixing interval for every anaerobic digestion operating plan.
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Affiliation(s)
- Ibrahim Denka Kariyama
- Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, China
| | - Xiaodong Zhai
- Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, China
| | - Binxin Wu
- Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, China.
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Zhang J, Zhao W, Zhang H, Wang Z, Fan C, Zang L. Recent achievements in enhancing anaerobic digestion with carbon- based functional materials. BIORESOURCE TECHNOLOGY 2018; 266:555-567. [PMID: 30037522 DOI: 10.1016/j.biortech.2018.07.076] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 07/11/2018] [Accepted: 07/14/2018] [Indexed: 05/22/2023]
Abstract
Carbon-based materials such as graphite, graphene, biochar, activated carbon, carbon cloth and nano-tube, and maghemite and magnetite carbons are capable for adsorbing chemicals onto their surfaces. Currently, this review is to highlight the relevance of carbons in enhancing hydrogen or methane production. Some key roles of carbons in improving cell growth, enrichment and activity, and accelerating their co-metabolisms were elaborated with regard to their effects on syntrophic communities, interspecies electron transfer, buffering capacity, biogas upgrading, and fertilizer nutrient retention and land application. Carbons can serve as a habitation for microbial immobilization, and a provision for bioelectrical connections among cells, and provide some essential elements for anaerobes. Besides, an outlook on the possible options towards the large scale and improvement solutions has been provided. Further studies in this area could be encouraged to intend and operate continuous mode by designing carbon-amended bioreactor with stability and reliability.
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Affiliation(s)
- Jishi Zhang
- College of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Science), Jinan 250353, China.
| | - Wenqian Zhao
- College of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Science), Jinan 250353, China
| | - Huiwen Zhang
- School of Pharmaceutical Sciences, Shandong University of Traditional Chinese Medicine, Jinan 250355, China
| | - Zejie Wang
- College of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Science), Jinan 250353, China
| | - Chuanfang Fan
- College of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Science), Jinan 250353, China
| | - Lihua Zang
- College of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Science), Jinan 250353, China
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Tsui TH, Ekama GA, Chen GH. Quantitative characterization and analysis of granule transformations: Role of intermittent gas sparging in a super high-rate anaerobic system. WATER RESEARCH 2018; 139:177-186. [PMID: 29649702 DOI: 10.1016/j.watres.2018.04.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/06/2018] [Accepted: 04/01/2018] [Indexed: 05/14/2023]
Abstract
Knowledge of leveraging biomass characteristics is essential for achieving a microbial community with a desired structure to optimize anaerobic bioreactor performance. This study investigates the successive granule transformations in a high-rate anaerobic system with intermittent gas sparging and sequential increases in organic loading rates (OLRs), by establishing the correlations between the granule microstructures and reactor operating parameters. Over the course of a 196-day lab-scale trial, the granules were visualized in various stages using scanning electron microscopy, and digital image processing was applied for further quantifying their surface properties. Correlation analyses revealed that irregularities of the granule microstructures (surface properties, specific surface area and pore volume) emerged at stage 4 when the OLR was 13.31 kg COD/m3·day and in stage 5 in the absence of gas sparging. The loading ratio (substrate surface loading to upward velocity) was identified to be the main parameter controlling the granule transformations, and the surface structures were classified into three categories for further interpretation. Confocal laser scanning microscopy analyses showed that the granule core started to hollow out from stage 4. It is also found that a rough granule surface helped accelerate the growth of the granular diameter under gas sparging. Overall, this study not only establish quantitative correlations between the granules microstructures and reactor operating parameters, but also shed light on the use of intermittent gas sparging to control the surface properties of anaerobic granules in high-rate anaerobic bioreactors.
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Affiliation(s)
- To-Hung Tsui
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Water Technology Center, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Hong Kong Branch of Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - George A Ekama
- Water Research Group, Department of Civil Engineering, University of Cape Town, Cape Town, South Africa
| | - Guang-Hao Chen
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Water Technology Center, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Hong Kong Branch of Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Fok Ying Tung Research Institute, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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Tacconi C, Cucina M, Pezzolla D, Zadra C, Gigliotti G. Effect of the mycotoxin aflatoxin B1 on a semi-continuous anaerobic digestion process. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 78:467-473. [PMID: 32559934 DOI: 10.1016/j.wasman.2018.06.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 04/26/2018] [Accepted: 06/06/2018] [Indexed: 06/11/2023]
Abstract
Cereals are primary crops and are the most important raw material for feed and food production. Increasing aflatoxin B1 (AFB1) contamination of corn is an emerging issue, and disposal procedures for AFB1-contaminated corn are not currently defined. Recovery of contaminated corn through anaerobic digestion may represent a suitable strategy for its valorisation; however, only a few studies concerning the effect of AFB1 on anaerobic processes can be found. Thus, the purpose of the present work was to evaluate the effect of the mycotoxin AFB1 on a semi-continuous anaerobic digestion (AD) process. Semi-continuous trials were carried out, and the biomethane production from ABF1-contaminated feedstocks (25, 50, and 100 µg kg-1 AFB1 wet weight) was compared to that from non-contaminated feedstock. Moreover, the feasibility of the agronomic re-use of the digestate, and the fate of AFB1 during AD was assessed. No adverse effect of 25 µg kg-1 AFB1 contamination of feedstock on biomethane yield was observed. In contrast, 100 µg kg-1 AFB1 in the feedstock resulted in inhibition of the process due to the accumulation of organic acids, and to the decrease of the pH in the digestate (from 8.1 to 5.4). The continuous addition of AFB1-contaminated feedstock led to accumulation of the mycotoxin in the digestates. Consequently, a composting process should always precede the agricultural re-use of digestates in order to remove AFB1 and the residual phytotoxicity.
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Affiliation(s)
- Chiara Tacconi
- Department of Civil and Environmental Engineering, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy
| | - Mirko Cucina
- Department of Civil and Environmental Engineering, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy
| | - Daniela Pezzolla
- Department of Civil and Environmental Engineering, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy.
| | - Claudia Zadra
- Department of Pharmaceutical Sciences, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy
| | - Giovanni Gigliotti
- Department of Civil and Environmental Engineering, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy
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Wiedemann L, Conti F, Saidi A, Sonnleitner M, Goldbrunner M. Modeling Mixing in Anaerobic Digesters with Computational Fluid Dynamics Validated by Experiments. Chem Eng Technol 2018. [DOI: 10.1002/ceat.201800083] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Leonhard Wiedemann
- Technische Hochschule Ingolstadt; Institute of new Energy Systems; Esplanade 10 85049 Ingolstadt Germany
| | - Fosca Conti
- Technische Hochschule Ingolstadt; Institute of new Energy Systems; Esplanade 10 85049 Ingolstadt Germany
- University of Padova; Department of Chemical Sciences; via Marzolo 1 35141 Padova Italy
| | - Abdessamad Saidi
- Technische Hochschule Ingolstadt; Institute of new Energy Systems; Esplanade 10 85049 Ingolstadt Germany
| | - Matthias Sonnleitner
- Technische Hochschule Ingolstadt; Institute of new Energy Systems; Esplanade 10 85049 Ingolstadt Germany
| | - Markus Goldbrunner
- Technische Hochschule Ingolstadt; Institute of new Energy Systems; Esplanade 10 85049 Ingolstadt Germany
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Effect of Time and Mixing in Thermal Pretreatment on Faecal Indicator Bacteria Inactivation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15061225. [PMID: 29891776 PMCID: PMC6024947 DOI: 10.3390/ijerph15061225] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 05/28/2018] [Accepted: 06/08/2018] [Indexed: 11/28/2022]
Abstract
Faecal indicator bacteria of faecal coliform, Salmonella spp., and faecal Streptococcus are present at high levels in faecal sludge and affect human health. Mesophilic anaerobic digestion cannot reduce faecal indicator bacteria to meet the standards for biosolids; therefore, the thermal pretreatment of faecal sludge is essential. The main objectives of this research were to evaluate the effect of thermal (70 °C) pretreatment time (20, 40, 60, 80, 100, and 120 min) and mixing velocity gradient (no mixing, 133, 191, and 238 s−1) on faecal indicator bacteria inactivation and determine the kinetics of the inactivation. The results showed that mixing has a more positive effect on pretreatment; thermal pretreatment with mixing was able to completely inactivate faecal indicator bacteria within 80 min, and inactivation followed first-order kinetics. In addition, under optimal mixing at a velocity gradient 191 s−1, the thermal pretreatment with mixing had a positive effect on the sludge solubilisation. Soluble chemical oxygen demand (SCOD, 71,430 mg L−1) and soluble protein (7.96 g L−1) were higher than the values obtained with thermal pretreatment without mixing, which were a SCOD value of 63,600 mg L−1 and soluble protein of 6.78 g L−1.
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Zhang L, Zhang J, Loh KC. Activated carbon enhanced anaerobic digestion of food waste - Laboratory-scale and Pilot-scale operation. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 75:270-279. [PMID: 29456123 DOI: 10.1016/j.wasman.2018.02.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 01/08/2018] [Accepted: 02/11/2018] [Indexed: 06/08/2023]
Abstract
Effects of activated carbon (AC) supplementation on anaerobic digestion (AD) of food waste were elucidated in lab- and pilot-scales. Lab-scale AD was performed in 1 L and 8 L digesters, while pilot-scale AD was conducted in a 1000 L digester. Based on the optimal dose of 15 g AC per working volume derived from the 1 L digester, for the same AC dosage in the 8 L digester, an improved operation stability coupled with a higher methane yield was achieved even when digesters without AC supplementation failed after 59 days due to accumulation of substantial organic intermediates. At the same time, color removal from the liquid phase of the digestate was dramatically enhanced and the particle size of the digestate solids was increased by 53% through AC supplementation after running for 59 days. Pyrosequencing of 16S rRNA gene showed the abundance of predominant phyla Firmicutes, Elusimicrobia and Proteobacteria selectively enhanced by 1.7-fold, 2.9-fold and 2.1-fold, respectively. Pilot-scale digester without AC gave an average methane yield of 0.466 L⋅(gVS)-1⋅d-1 at a composition of 53-61% v/v methane. With AC augmentation, an increase of 41% in methane yield was achieved in the 1000 L digester under optimal organic loading rate (1.6 g VSFW·L-1·d-1).
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Affiliation(s)
- Le Zhang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, S117576, Singapore
| | - Jingxin Zhang
- NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, S138602, Singapore
| | - Kai-Chee Loh
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, S117576, Singapore.
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47
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Role and Potential of Direct Interspecies Electron Transfer in Anaerobic Digestion. ENERGIES 2018. [DOI: 10.3390/en11010107] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Khoshnevisan B, Tsapekos P, Alvarado-Morales M, Angelidaki I. Process performance and modelling of anaerobic digestion using source-sorted organic household waste. BIORESOURCE TECHNOLOGY 2018; 247:486-495. [PMID: 28968570 DOI: 10.1016/j.biortech.2017.09.122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/15/2017] [Accepted: 09/17/2017] [Indexed: 06/07/2023]
Abstract
Three distinctive start-up strategies of biogas reactors fed with source-sorted organic fraction of municipal solid waste were investigated to reveal the most reliable procedure for rapid process stabilization. Moreover, the experimental results were compared with mathematical modeling outputs. The initial inoculations to start-up the reactors were 10, 50 and 100% of the final working volume. While a constant feeding rate of 7.8gVS/d was considered for the control reactor, the organic loading rate for fed-batch reactors with 10 and 50% inoculation was progressively increased during a period of 60 and 13days, respectively. The results clearly demonstrated that an exponentially feeding strategy, considering 50% inoculation relative to final volume, can significantly decrease the alternatively prolonged period to reach steady conditions, as observed by high biogas and methane production rates. The combination of both experimental and modelling/simulation succeeded in optimizing the start-up process for anaerobic digestion of biopulp under mesophilic conditions.
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Affiliation(s)
- Benyamin Khoshnevisan
- Department of Mechanical Engineering of Agricultural machinery, Faculty of Agricultural Engineering and Technology, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran; Department of Environmental Engineering, Technical University of Denmark, DK-2800 Kgs Lyngby, Denmark
| | - Panagiotis Tsapekos
- Department of Environmental Engineering, Technical University of Denmark, DK-2800 Kgs Lyngby, Denmark
| | - Merlin Alvarado-Morales
- Department of Environmental Engineering, Technical University of Denmark, DK-2800 Kgs Lyngby, Denmark
| | - Irini Angelidaki
- Department of Environmental Engineering, Technical University of Denmark, DK-2800 Kgs Lyngby, Denmark.
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Review of Upflow Anaerobic Sludge Blanket Reactor Technology: Effect of Different Parameters and Developments for Domestic Wastewater Treatment. J CHEM-NY 2018. [DOI: 10.1155/2018/1596319] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The upflow anaerobic sludge blanket (UASB) reactor has been recognized as an important wastewater treatment technology among anaerobic treatment methods. The objective of this study was to perform literature review on the treatment of domestic sewage using the UASB reactor as the core component and identifying future areas of research. The merits of anaerobic and aerobic bioreactors are highlighted and other sewage treatment technologies are compared with UASB on the basis of performance, resource recovery potential, and cost. The comparison supports UASB as a suitable option on the basis of performance, green energy generation, minimal space requirement, and low capital, operation, and maintenance costs. The main process parameters such as temperature, hydraulic retention time (HRT), organic loading rate (OLR), pH, granulation, and mixing and their effects on the performance of UASB reactor and hydrogen production are presented for achieving optimal results. Feasible posttreatment steps are also identified for effective discharge and/or reuse of treated water.
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Han D, Lee CY, Chang SW, Kim DJ. Enhanced methane production and wastewater sludge stabilization of a continuous full scale thermal pretreatment and thermophilic anaerobic digestion. BIORESOURCE TECHNOLOGY 2017; 245:1162-1167. [PMID: 28863991 DOI: 10.1016/j.biortech.2017.08.108] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 08/16/2017] [Accepted: 08/17/2017] [Indexed: 06/07/2023]
Abstract
A continuous full scale thermophilic anaerobic digestion (AD) of wastewater sludge in conjunction with thermal pretreatment was developed for enhanced CH4 production as well as sludge stabilization and reduction. Continuous thermal sludge treatment obtained 45.5, 51.7, and 26.1% of hydrolysis based on TS, VS, and COD at 160°C for 30min. After AD, TS, VS, and COD removal efficiencies reached 54.7, 60.4, and 59.2%, respectively, at 3.50kgVS/m3·d. Maximum CH4 yield (0.35m3 CH4/kg VSadd) was obtained at 2.49kgVS/m3·d and less, and the yield decreased with increasing sludge load while net available energy production increased. Continuous thermal sludge treatment and thermophilic AD enhanced CH4 production and solids reduction and showed stable performance for full scale application.
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Affiliation(s)
- Dongwoo Han
- R&D Center, ENTECS Co., Ltd. 229 (Ok-dong), Pyeongdongsandan-ro, Gwangsan-gu, Gwangju 62416, Republic of Korea
| | - Chang-Yeol Lee
- Chemicals R&D Center, SK Chemicals 310 Pangyo-ro, Bundang-gu, Seongnam, Gyeonggi 13494, Republic of Korea
| | - Soon W Chang
- Department of Environmental Energy & Engineering, Kyonggi University, Suwon, Gyeonggi 16277, Republic of Korea
| | - Dong-Jin Kim
- Department of Environmental Sciences and Biotechnology & Institute of Energy and Environment, Hallym University, Chuncheon, Gangwon 24252, Republic of Korea.
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