1
|
Kumar P, Yan JZ, Rauch N, Dabiri S, Rauch W. Lagrangian solver for coupling hydrodynamics with biokinetic conversion modelling in anaerobic digesters. WATER RESEARCH 2024; 252:121211. [PMID: 38309059 DOI: 10.1016/j.watres.2024.121211] [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: 10/16/2023] [Revised: 01/14/2024] [Accepted: 01/26/2024] [Indexed: 02/05/2024]
Abstract
Conventional anaerobic digestion models used in wastewater treatment plants suffer from inaccuracies due to the limited consideration given to hydrodynamics within the digester tank. A solution to this is to combine computational fluid dynamics simulations with anaerobic models. This paper introduces a novel methodology in the form of a software toolbox that implements the standard anaerobic digestion model no.1 in C++ and can interface with particle-based Lagrangian simulations. This method provides significantly more insights into the biochemical conversion process by accounting for the impact of the hydrodynamics on the biochemical reactions. The paper presents the background of the method along with a conceptual and numerical verification. It also presents a case study of a 3D lab scale digester comparing the results from the solver with the standard anaerobic digestion model. This integrated approach can be used by operators and designers for optimisations and also for predictive modelling.
Collapse
Affiliation(s)
- Prashant Kumar
- Room 312, Unit of Environmental Engineering, University of Innsbruck, Technikerstrasse 23b, Innsbruck, 6020, Austria
| | - Jeremy Z Yan
- Room 312, Unit of Environmental Engineering, University of Innsbruck, Technikerstrasse 23b, Innsbruck, 6020, Austria
| | - Nikolaus Rauch
- Room 3N04, Interactive Graphics and Simulation Group, University of Innsbruck, Technikerstrasse 21a, Innsbruck, 6020, Austria
| | - Soroush Dabiri
- Room 312, Unit of Environmental Engineering, University of Innsbruck, Technikerstrasse 23b, Innsbruck, 6020, Austria
| | - Wolfgang Rauch
- Room 311, Unit of Environmental Engineering, University of Innsbruck, Technikerstrasse 23b, Innsbruck, 6020, Austria.
| |
Collapse
|
2
|
Diaz R, Goswami A, Clark HC, Michelson R, Goel R. Volatile fatty acid production from primary and secondary sludges to support efficient nutrient management. CHEMOSPHERE 2023:138984. [PMID: 37315862 DOI: 10.1016/j.chemosphere.2023.138984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 06/16/2023]
Abstract
Enhanced hydrolysis of sludges during fermentation is an important factor to achieve solubilization of complex carbon sources and increase the amount of soluble COD that microorganisms could use as food during biological nutrient removal processes. This research shows that a combination of mixing, bioaugmentation, and co-fermentation can be used to increase the hydrolysis of sludges and enhanced the production of volatile fatty acids (VFA). Mixing of primary sludge (PS) at 350 revolutions per minute (RPM) during fermentation increased the hydrolysis of the sludge and increased the soluble chemical oxygen demand (sCOD) by 72% compared to no mixing. Mixing also increased the production of VFA by 60% compared to no mixing conditions. PS hydrolysis was also evaluated using bioaugmentation with the bacteria Bacillus amyloliquefacients, a known producer of the biosurfactant surfactin. Results showed that bioaugmentation enhanced the hydrolysis of the PS by increasing the amount of soluble carbohydrates and soluble proteins present in the form of sCOD. Methanogenesis experiments performed with co-fermentation of decanted primary sludge (PS) and raw waste-activated sludge (WAS) at 75:25 and 50:50 ratios displayed a decreased in production of total biogas by 25.58% and 20.95% and a reduction on methane production by 20.00% and 28.76% respectively, compared to co-fermentation of raw sludges. Compared to fermentation of the sludges separately, co-fermentation of PS and WAS increased the production of VFA and it was determined that 50:50 was the optimum co-fermentation ratio for production of VFA while reducing the reintroduction of nutrients produced during the fermentation process to BNR processes.
Collapse
Affiliation(s)
- Ruby Diaz
- Civil & Environmental Engineering, University of Utah, Salt Lake City, USA
| | - Anjan Goswami
- Civil & Environmental Engineering, University of Utah, Salt Lake City, USA
| | - Herald C Clark
- Civil & Environmental Engineering, University of Utah, Salt Lake City, USA
| | | | - Ramesh Goel
- Civil & Environmental Engineering, University of Utah, Salt Lake City, USA.
| |
Collapse
|
3
|
Dabiri S, Kumar P, Rauch W. Integrating biokinetics with computational fluid dynamics for energy performance analysis in anaerobic digestion. BIORESOURCE TECHNOLOGY 2023; 373:128728. [PMID: 36774990 DOI: 10.1016/j.biortech.2023.128728] [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: 12/23/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
Anaerobic digestion (AD) is an effective process for decomposing organic matter in wastewater treatment plants (WWTPs) where highly efficient digesters properly mix the sludge. To ensure a uniform substance distribution, a comprehensive modeling method is necessary. Computational fluid dynamics (CFD) helps in the modeling of AD tanks but few studies have focused on integrating hydrodynamics with biokinetics because of complex AD processes. The current study presents a new CFD platform for estimating the biokinetics of WWTPs to assess the energy performance of AD tanks. The presented method is validated by numerical and experimental studies, and facilitates a link between methane production and mixing energy consumption. The on-site settings of the recirculation mixing system in the studied WWTP was able to prepare a uniform mixture of the material. However, reducing mixing rate to decrease energy consumption did not lead to proper mixing quality.
Collapse
Affiliation(s)
- Soroush Dabiri
- Unit of Environmental Engineering, University of Innsbruck, 6020 Innsbruck, Austria.
| | - Prashant Kumar
- Unit of Environmental Engineering, University of Innsbruck, 6020 Innsbruck, Austria
| | - Wolfgang Rauch
- Unit of Environmental Engineering, University of Innsbruck, 6020 Innsbruck, Austria
| |
Collapse
|
4
|
Chen J, Risberg M, Westerlund L, Jansson U, Wang C, Lu X, Ji X. Heat-transfer performance of twisted tubes for highly viscous food waste slurry from biogas plants. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:74. [PMID: 35794672 PMCID: PMC9261055 DOI: 10.1186/s13068-022-02156-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/11/2022] [Indexed: 11/10/2022]
Abstract
Abstract
Background
The use of food waste as feedstock shows high production of biogas via anaerobic digestion, but requires efficient heat transfer in food waste slurry at heating and cooling processes. The lack of rheological properties hampered the research on the heat-transfer process for food waste slurry. Referentially, the twisted hexagonal and elliptical rubes have been proved as the optimal enhanced geometry for heat transfer of medium viscous slurries with non-Newtonian behavior and Newtonian fluids, respectively. It remains unknown whether improvements can be achieved by using twisted geometries in combination with food waste slurry in processes including heating and cooling.
Results
Food waste slurry was observed to exhibit highly viscous, significant temperature-dependence, and strongly shear-thinning rheological characteristics. Experiments confirmed the heat-transfer enhancement of twisted hexagonal tubes for food waste slurry and validated the computational fluid dynamics-based simulations with an average deviation of 14.2%. Twisted hexagonal tubes were observed to be more effective at low-temperature differences and possess an enhancement factor of up to 2.75; while twisted elliptical tubes only exhibited limited heat-transfer enhancement at high Reynolds numbers. The heat-transfer enhancement achieved by twisted hexagonal tubes was attributed to the low dynamic viscosity in the boundary layer induced by the strong and continuous shear effect near the walls of the tube.
Conclusions
This study determined the rheological properties of food waste slurry, confirmed the heat-transfer enhancement of the twisted hexagonal tubes experimentally and numerically, and revealed the mechanism of heat-transfer enhancement based on shear rate distributions.
Collapse
|
5
|
Cao Q, Zhang W, Lian T, Wang S, Yin F, Zhou T, Wei X, Dong H. Revealing mechanism of micro-aeration for enhancing volatile fatty acids production from swine manure. BIORESOURCE TECHNOLOGY 2022; 365:128140. [PMID: 36252761 DOI: 10.1016/j.biortech.2022.128140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
Micro-aeration is considered a new strategy for improving volatile fatty acids (VFAs) production of agricultural waste. This study investigated the effect and mechanism of micro-aeration of air and oxygen (O2) on VFAs production from swine manure. The results showed that Air-micro-aeration had the most significant improvement effect, with the highest VFAs of 8.21 g/L, which was increased by 22.4%. Moreover, the mixing effects of different micro-aeration were limited, and the microbial communities significantly varied. Firmicutes and Bacteroidota were the dominant hydrolytic and acidogenic bacteria, and Air-micro-aeration preferentially promoted electron transfer activity and energy generation. Methanosarcina, Methanocorpusculum, and Methanobrevibacter can adapt to environmental changes according to their different oxygen tolerance, and the consumption and conversion of VFAs by methanogens were slow under Air-micro-aeration condition. This study revealed mechanism of micro-aeration for improving VFAs production from swine manure, providing a theoretical basis for micro-aeration regulation optimization.
Collapse
Affiliation(s)
- Qitao Cao
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Wanqin Zhang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Tianjing Lian
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, PR China
| | - Shunli Wang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Fubin Yin
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Tanlong Zhou
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Xiaoman Wei
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Hongmin Dong
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China.
| |
Collapse
|
6
|
CFD simulation and performance evaluation of gas mixing during high solids anaerobic digestion of food waste. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2021.108279] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
7
|
Yang H, Deng L, Wu J, Wang W, Zheng D, Wang Z, Liu Y. Intermittent air mixing system for anaerobic digestion of animal wastewater: Operating conditions and full-scale validation. BIORESOURCE TECHNOLOGY 2021; 335:125304. [PMID: 34029867 DOI: 10.1016/j.biortech.2021.125304] [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: 04/02/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 06/12/2023]
Abstract
An air mixing system for anaerobic digestion has been proved to be beneficial for methane production. The aim of the present study was to further investigate the appropriate conditions for air mixing. The effective methane production time (EMPT) was defined to determine the air mixing time in the article. The results indicated that the appropriate aeration intensity was 66.7 mL air per volume of reactor per min and mixing time was 1.5 min. When air mixing time exceeded 3 min on each occasion, total CH4 production was less than that achieved under the no mixing condition due to a decrease in the EMPT. In addition, the possibility of air mixing was evaluated in an anaerobic full-scale plant comprising a continuous stirred tank reactor. One year of operating data validated the feasibility of air mixing during the anaerobic digestion of swine wastewater.
Collapse
Affiliation(s)
- Hongnan Yang
- Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China; Key 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; Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China.
| | - Jianwang Wu
- Shijiazhuang Chengding Environmental Protection Technology Co. Ltd., Shijiazhuang 050000, PR China
| | - Wenguo Wang
- Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China; Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China
| | - Dan Zheng
- Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China; Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China
| | - Zhiyong Wang
- Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China; Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China
| | - Yi Liu
- Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China; Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Chengdu 610041, PR China
| |
Collapse
|
8
|
Miryahyaei S, Das T, Othman M, Batstone D, Eshtiaghi N. Anaerobic co-digestion of sewage sludge with cellulose, protein, and lipids: Role of rheology and digestibility. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 731:139214. [PMID: 32417486 DOI: 10.1016/j.scitotenv.2020.139214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/24/2020] [Accepted: 05/02/2020] [Indexed: 06/11/2023]
Abstract
Rheology is known to have an impact on the performance of digesters, but the effect of additional substrates (co-digestion) is poorly understood. The main objective of this study was to investigate the effects of the addition of cellulose, protein and lipids to substrates on the rheological behaviour and biogas production of the mixture of primary sludge (PS) and waste-activated sludge (WAS) in a batch system. A mixture of PS and WAS to form the main substrate was anaerobically co-digested with different types of organic matter (cellulose, protein and lipids) as co-substrates at different co-substrate to main substrate ratios of 2-8 (wt%) under mesophilic conditions and below ammonia inhibition levels. Yield stress (τy) and the flow consistency index (k) of the combined feed in the case of cellulose and protein were significantly dependent on the amount of co-substrate added, while there was an insignificant impact on these properties when lipids were added. Cellulose significantly increased τy and k in the feed, which resulted in poor fluidity and the improper homogenisation of the digester content, and consequently decreased the biogas yield. In contrast, the biogas yield was improved through the addition of 2% to 6% protein despite an increase in τy and k of the feed, but the methane yield decreased at 7% and 8% levels of protein concentration. This observation indicates that the threshold for τy and k of the digester media depends on the organic nature and digestibility of the substrate. There was no significant impact on the flow properties of the initial mixture when lipids were added, and their addition increased the biogas yield. A first-order kinetic reaction model was used for predicting the yield of methane from these digesters. The rate constant values revealed an increasing trend, with the highest for protein then lipids then cellulose.
Collapse
Affiliation(s)
- S Miryahyaei
- Chemical and Environmental Engineering, School of Engineering, RMIT University, 3001 Melbourne, Australia
| | - T Das
- Chemical and Environmental Engineering, School of Engineering, RMIT University, 3001 Melbourne, Australia
| | - M Othman
- Chemical and Environmental Engineering, School of Engineering, RMIT University, 3001 Melbourne, Australia
| | - D Batstone
- Advanced Water Management Centre, The University of Queensland, Brisbane, Australia
| | - N Eshtiaghi
- Chemical and Environmental Engineering, School of Engineering, RMIT University, 3001 Melbourne, Australia.
| |
Collapse
|
9
|
Evaluation of Microaeration and Sound to Increase Biogas Production from Poultry Litter. ENVIRONMENTS 2020. [DOI: 10.3390/environments7080062] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Microaeration, wherein small amounts of air are introduced into otherwise anaerobic digesters, has been shown to enhance biogas production. This occurs by fostering the growth of facultatively aerobic bacteria and production of enzymes that enhance the degradation of complex polymers such as cellulose. The treatment of anaerobic digestate with sound at sonic frequencies (<20 kHz) has also been shown to improve biogas production. Microaeration at a rate of 800 mL day−1, treatment with a 1000-Hz sine wave, and combined microaeration/sound were compared to a control digester for the production of biogas and their effect on wastewater quality. Poultry litter from a facility using wood chips as bedding was used as feed. The initial feeding rate was 400 g week−1, and this was slowly increased to a final rate of 2400 g week−1. Compared to the control, sound treatment, aeration, and combined sound/aeration produced 17%, 32%, and 28% more biogas. The aeration alone treatment may have been more effective than combined aeration/sound due to the sound interfering with retention of aeration or the formation of free radicals during cavitation. Digesters treated with sound had the highest concentrations of suspended solids, likely due to cavitation occurring within the sludge and the resulting suspension of fine particles by bubbles.
Collapse
|
10
|
Linking CFD and Kinetic Models in Anaerobic Digestion Using a Compartmental Model Approach. Processes (Basel) 2020. [DOI: 10.3390/pr8060703] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Understanding mixing behavior and its impact on conversion processes is essential for the operational stability and conversion efficiency of anaerobic digestion (AD). Mathematical modelling is a powerful tool to achieve this. Direct linkage of Computational Fluid Dynamics (CFD) and the kinetic model is, however, computationally expensive, given the stiffness of the kinetic model. Therefore, this paper proposes a compartmental model (CM) approach, which is derived from a converged CFD solution to understand the performance of AD under non-ideal mixing conditions and with spatial variation of substrates, biomass, pH, and specific biogas and methane production. To quantify the effect of non-uniformity on the reactor performance, the CM implements the Anaerobic Digestion Model 1 (ADM1) in each compartment. It is demonstrated that the performance and spatial variation of the biochemical process in a CM are significantly different from a continuously stirred tank reactor (CSTR) assumption. Hence, the assumption of complete mixed conditions needs attention concerning the AD performance prediction and biochemical process non-uniformities.
Collapse
|
11
|
Kusmayadi A, Suyono EA, Nagarajan D, Chang JS, Yen HW. Application of computational fluid dynamics (CFD) on the raceway design for the cultivation of microalgae: a review. J Ind Microbiol Biotechnol 2020; 47:373-382. [PMID: 32240448 DOI: 10.1007/s10295-020-02273-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/24/2020] [Indexed: 10/24/2022]
Abstract
Microalgae are a potential solution to supersede fossil fuels and produce renewable energy. The major obstacle to the commercialization of microalgae-based biofuels is the high production cost, including nutritional requirements, photobioreactor design, and downstream processes. As for the photobioreactor design, open ponds have been adopted by major commercial plants for their economic advantages. Raceway is a popular type among open ponds. Nevertheless, the fluid dynamics of the raceway operation is quite complex. Software simulation based on Computational Fluid Dynamics is an upcoming strategy for optimizing raceway design. The optimization intends to affect light penetration, particle distribution, mass transfer, and biological kinetics. This review discusses how this strategy can be helpful to design a highly productive raceway pond-based microalgal culture system.
Collapse
Affiliation(s)
- Adi Kusmayadi
- Department of Chemical and Material Engineering, Tunghai University, Taichung, Taiwan
| | - Eko Agus Suyono
- Faculty of Biology, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Dillirani Nagarajan
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Jo-Shu Chang
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan.,Developmental Center for Circular Resources and Valorization Technology, Tunghai University, Taichung, Taiwan
| | - Hong-Wei Yen
- Department of Chemical and Material Engineering, Tunghai University, Taichung, Taiwan.
| |
Collapse
|
12
|
Tobo YM, Rehman U, Bartacek J, Nopens I. Partial integration of ADM1 into CFD: understanding the impact of diffusion on anaerobic digestion mixing. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 81:1658-1667. [PMID: 32644959 DOI: 10.2166/wst.2020.076] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Sufficient mixing is crucial for the proper performance of anaerobic digestion (AD), creating a homogeneous distribution of soluble substrates, biomass, pH, and temperature. The opaqueness of the sludge and mode of operation make it challenging to study AD mixing experimentally. Therefore, hydrodynamics modelling employing computational fluid dynamics (CFD) is often used to investigate this mixing. However, CFD models mostly do not include biochemical reactions and, hence, ignore the effect of diffusion-induced transport on AD heterogeneity. The novelty of this work is the partial integration of Anaerobic Digestion Model no. 1 (ADM1) into the CFD model. The aim is to better understand the effect of advection-diffusion transport on the homogenization of soluble substrates and biomass. Furthermore, AD homogeneity analysis in terms of concentration distribution is proposed rather than the traditional velocity distributions. The computed results indicate that including diffusion-induced transport affects the homogeneity of AD.
Collapse
Affiliation(s)
- Yohannis Mitiku Tobo
- BIOMATH, Department of Data Analysis and Mathematical Modelling, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium E-mail: ; Department of Water Technology and Environmental Engineering, University of Chemistry and Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic
| | - Usman Rehman
- AM-TEAM, Oktrooiplein 1- Box 601, 9000 Ghent, Belgium
| | - Jan Bartacek
- Department of Water Technology and Environmental Engineering, University of Chemistry and Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic
| | - Ingmar Nopens
- BIOMATH, Department of Data Analysis and Mathematical Modelling, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium E-mail:
| |
Collapse
|
13
|
Ma SJ, Ma HJ, Hu HD, Ren HQ. Effect of mixing intensity on hydrolysis and acidification of sewage sludge in two-stage anaerobic digestion: Characteristics of dissolved organic matter and the key microorganisms. WATER RESEARCH 2019; 148:359-367. [PMID: 30396101 DOI: 10.1016/j.watres.2018.10.058] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/18/2018] [Accepted: 10/21/2018] [Indexed: 06/08/2023]
Abstract
Mixing should be optimized in anaerobic digestion (AD) systems to achieve excellent biomaterials production in the sewage sludge (SS) management in wastewater treatment plant. AD depends on the coordinated activity of hydrolysis, acidification and methanogenesis. However, the effect of mixing intensity on characteristics of hydrolysis and acidification in AD of SS is still poorly understood. This study focused on the mixing intensity (30, 60, 90 and 120 rpm) effect on the characteristics of dissolved organic matter (DOM) and the key microorganisms in the hydrolysis and acidification of SS. Results showed that enhanced hydrolysis and acidification efficiency was obtained at mixing of 90 and 120 rpm (p < 0.05), while the maximum acetic acid (388 ± 21 mg/L) was produced at 90 rpm. Mixing at 90 rpm enhanced the release of protein and polysaccharide as well as humic acid. Further analyses of DOM molecular features revealed that 90 rpm led to the highest molecular diversity and easily biodegradable molecules (lipid and proteins/amino sugars), which contributed to the maximum hydrolysis and acidification efficiency. Firmicutes and Actinobacteria significantly increased with mixing intensity (p<0.05), and Chloroflexi and Fusobacteria were enriched at mixing of 90 rpm, which favored the hydrolysis of SS. The enrichment of Clostridium XI and Clostridium sensu stricto contributed to the acidification of DOM at 90 and 120 rpm. The results of this study can advance our knowledge about mixing intensity effects on the AD systems of SS. This research also showed how increasing mixing intensity to a relatively high speed can enhance the hydrolysis and acidification efficiency of SS.
Collapse
Affiliation(s)
- Si-Jia Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Hai-Jun Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Hai-Dong Hu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Hong-Qiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China.
| |
Collapse
|
14
|
Dapelo D, Bridgeman J. Assessment of mixing quality in full-scale, biogas-mixed anaerobic digestion using CFD. BIORESOURCE TECHNOLOGY 2018; 265:480-489. [PMID: 29936352 DOI: 10.1016/j.biortech.2018.06.036] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/08/2018] [Accepted: 06/12/2018] [Indexed: 06/08/2023]
Abstract
An Euler-Lagrange CFD model is applied to a full-scale, biogas-mixed anaerobic digester to improve mixing efficiency and improve overall performance. Two quantitative mixing criteria previously adopted in anaerobic digestion (viz., uniformity index and dead volume) are critically assessed for the first time. A novel qualitative method is introduced to clarify the output of the quantitative methods. The first-ever quantitative assessment of mixing quality in full-scale, biogas-mixed anaerobic digestion is then proposed, and a strategy to improve mixing, involving the combined use of concentric nozzle manifolds at the base of the digester, is evaluated.
Collapse
Affiliation(s)
- Davide Dapelo
- Faculty of Engineering and Informatics, University of Bradford, Bradford BD7 1DP, United Kingdom.
| | - John Bridgeman
- Faculty of Engineering and Informatics, University of Bradford, Bradford BD7 1DP, United Kingdom
| |
Collapse
|
15
|
Effect of Freshwater Washing Pretreatment on Sargassum muticum as a Feedstock for Biogas Production. ENERGIES 2018. [DOI: 10.3390/en11071771] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
16
|
Cao X, Jiang K, Ding H, Yang P, Zhao Z, Xu G. Simulation and Analysis of Flow Field in Sludge Anaerobic Digestion Reactor based on Computational Fluid Dynamics. INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING 2018. [DOI: 10.1515/ijcre-2017-0175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractBecause of the complexity of flow and the opacity of sludge, usually we can’t gain a precise and comprehensive sight of sludge flow type and its associated flow characteristics in the anaerobic digestion (AD) reactor. In the present study, we focused on the sludge rheological properties as well as the flow behavior in the digester. The viscosity decreased with the increase of shear rate, and sludge as a kind of pseudo-plastic fluid was proved. Based on computational fluid dynamics (CFD), taking sludge rheological index and rotational speed into consideration, then the flow field distribution in the digester was obtained. The fluid velocity raised with increase in rotational speed, moreover, fluid near blades had higher velocity while it was almost stagnant in the areas near reactor bottom and top as well as reactor wall and stirring shaft. The effect of rheological index on improving the velocity of fluid farther from impeller exceeded the influence on fluid at the impeller installation height. Regarding dead zone fraction as an indicator of the mixing effect, it was recommended that the suitable rotational speed for AD of 96 % moisture content sludge is 40 r/min. Finally, the reactor performance was optimized respectively from impeller form and reactor configuration, the results showed that both combined impellers and oval reactor can reduce dead zone volumes and produce a better mixing effect.
Collapse
|
17
|
Xie S, Hai FI, Zhan X, Guo W, Ngo HH, Price WE, Nghiem LD. Anaerobic co-digestion: A critical review of mathematical modelling for performance optimization. BIORESOURCE TECHNOLOGY 2016; 222:498-512. [PMID: 27745967 DOI: 10.1016/j.biortech.2016.10.015] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/02/2016] [Accepted: 10/04/2016] [Indexed: 06/06/2023]
Abstract
Anaerobic co-digestion (AcoD) is a pragmatic approach to simultaneously manage organic wastes and produce renewable energy. This review demonstrates the need for improving AcoD modelling capacities to simulate the complex physicochemical and biochemical processes. Compared to mono-digestion, AcoD is more susceptible to process instability, as it operates at a higher organic loading and significant variation in substrate composition. Data corroborated here reveal that it is essential to model the transient variation in pH and inhibitory intermediates (e.g. ammonia and organic acids) for AcoD optimization. Mechanistic models (based on the ADM1 framework) have become the norm for AcoD modelling. However, key features in current AcoD models, especially relationships between system performance and co-substrates' properties, organic loading, and inhibition mechanisms, remain underdeveloped. It is also necessary to predict biogas quantity and composition as well as biosolids quality by considering the conversion and distribution of sulfur, phosphorus, and nitrogen during AcoD.
Collapse
Affiliation(s)
- Sihuang Xie
- Strategic Water Infrastructure Laboratory, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Faisal I Hai
- Strategic Water Infrastructure Laboratory, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Xinmin Zhan
- Civil Engineering, College of Engineering and Informatics, National University of Ireland, Galway, Ireland
| | - Wenshan Guo
- Centre for Technologies in Water and Wastewater, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Hao H Ngo
- Centre for Technologies in Water and Wastewater, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - William E Price
- Strategic Water Infrastructure Laboratory, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Long D Nghiem
- Strategic Water Infrastructure Laboratory, University of Wollongong, Wollongong, NSW 2522, Australia.
| |
Collapse
|
18
|
Kinyua MN, Zhang J, Camacho-Céspedes F, Tejada-Martinez A, Ergas SJ. Use of physical and biological process models to understand the performance of tubular anaerobic digesters. Biochem Eng J 2016. [DOI: 10.1016/j.bej.2015.11.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
19
|
Ali SS, Sun J. Physico-chemical pretreatment and fungal biotreatment for park wastes and cattle dung for biogas production. SPRINGERPLUS 2015; 4:712. [PMID: 26618101 PMCID: PMC4654729 DOI: 10.1186/s40064-015-1466-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 10/22/2015] [Indexed: 11/17/2022]
Abstract
With the rising demand for renewable energy and environmental protection, anaerobic digestion of biogas technology has attracted considerable attention within the scientific community. The effect of physico-chemical pretreatment on cellulose degradation followed by fungal treatment by Aspergillus terreus and Trichoderma viride to treat cellulosic biomass for enhancing its digestibility was investigated. The tested substrate was digested with and without physical, chemical, and biological treatment. Fresh leaves, dry leaves and cattle dung were characterized by a total solids content 35, 84 and 17 %, volatile solids content 81.2, 59.49 and 64.5 % and C/N ratio 31, 45.4 and 13.6, respectively. Biogas total volume was determined using water replacement technique, while methane volume was determined using precipitation of CO2 in 20 % NaOH solution. Pretreatment steps were carried out by using mechanical and chemical pretreatments using 2.5 % NaOH mixed with 2.5 % NH4OH for 15 days, followed by biological treatment of A. terreus and T. viride. The potential of pretreatment of substrate was studied at regular intervals of 0, 7, 14, 21, 28, 35, 42, 49, 56, 63 and 70 days determining the change in chemical and physical compositions of used substrates. Biogas production was 102.6 and 125.9 L/KgVS from untreated and pretreated substrate, respectively. On the other hand, methane production was 61.4 and 79.8 L/KgVS from untreated and pretreated substrate, respectively. In conclusion, Physical (milling), chemical (NaOH and NH4OH)
pretreatment in addition to fungal (A. terreus and T. viride) treatment for the tested substrate prior to AD was an efficient process for improvement of biogas and methane production.
Collapse
Affiliation(s)
- Sameh S Ali
- Botany Department, Faculty of Science, Tanta University, 31527 Tanta, Egypt ; Biofuels Institute, Jiangsu University, Zhenjiang, 212013 China
| | - Jianzhong Sun
- Biofuels Institute, Jiangsu University, Zhenjiang, 212013 China
| |
Collapse
|
20
|
Dapelo D, Alberini F, Bridgeman J. Euler-Lagrange CFD modelling of unconfined gas mixing in anaerobic digestion. WATER RESEARCH 2015; 85:497-511. [PMID: 26379205 DOI: 10.1016/j.watres.2015.08.042] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 07/13/2015] [Accepted: 08/22/2015] [Indexed: 06/05/2023]
Abstract
A novel Euler-Lagrangian (EL) computational fluid dynamics (CFD) finite volume-based model to simulate the gas mixing of sludge for anaerobic digestion is developed and described. Fluid motion is driven by momentum transfer from bubbles to liquid. Model validation is undertaken by assessing the flow field in a labscale model with particle image velocimetry (PIV). Conclusions are drawn about the upscaling and applicability of the model to full-scale problems, and recommendations are given for optimum application.
Collapse
Affiliation(s)
- Davide Dapelo
- University of Birmingham, School of Civil Engineering, Birmingham B15 2TT, United Kingdom.
| | - Federico Alberini
- University of Birmingham, School of Chemical Engineering, United Kingdom
| | - John Bridgeman
- University of Birmingham, School of Civil Engineering, Birmingham B15 2TT, United Kingdom
| |
Collapse
|
21
|
Jin Q, Chen L, Li A, Liu F, Long C, Shan A, Borthwick AGL. Comparison between solar utilization of a closed microalgae-based bio-loop and that of a stand-alone photovoltaic system. BIORESOURCE TECHNOLOGY 2015; 184:108-115. [PMID: 25465781 DOI: 10.1016/j.biortech.2014.10.131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 10/23/2014] [Accepted: 10/27/2014] [Indexed: 06/04/2023]
Abstract
This study compared the solar energy utilization of a closed microalgae-based bio-loop for energy efficient production of biogas with fertilizer recovery against that of a stand-alone photovoltaic (PV) system. The comparison was made from the perspective of broad life cycle assessment, simultaneously taking exergy to be the functional unit. The results indicated that the bio-loop was more environmentally competitive than an equivalent stand-alone PV system, but had higher economic cost due to high energy consumption during the operational phase. To fix the problem, a patented, interior pressurization scheduling method was used to operate the bio-loop, with microalgae and aerobic bacterial placed together in the same reactor. As a result, the overall environmental impact and total investment were respectively reduced by more than 75% and 84%, a vast improvement on the bio-loop.
Collapse
Affiliation(s)
- Qiang Jin
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Road, Minhang District, Shanghai 200240, PR China.
| | - Lei Chen
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Road, Minhang District, Shanghai 200240, PR China
| | - Aimin Li
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China
| | - Fuqiang Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China
| | - Chao Long
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China
| | - Aidang Shan
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Road, Minhang District, Shanghai 200240, PR China
| | - Alistair G L Borthwick
- Institute of Energy Systems, School of Engineering, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3JL, UK
| |
Collapse
|
22
|
Park S, Li Y. Integration of biological kinetics and computational fluid dynamics to model the growth ofNannochloropsis salinain an open channel raceway. Biotechnol Bioeng 2015; 112:923-33. [DOI: 10.1002/bit.25509] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 11/11/2014] [Accepted: 11/18/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Stephen Park
- Department of Food, Agricultural and Biological Engineering; The Ohio State University/Ohio Agricultural Research and Development Center; 1680 Madison Ave. Wooster Ohio 44691-4096
| | - Yebo Li
- Department of Food, Agricultural and Biological Engineering; The Ohio State University/Ohio Agricultural Research and Development Center; 1680 Madison Ave. Wooster Ohio 44691-4096
| |
Collapse
|
23
|
Vilà-Rovira A, Puig S, Balaguer MD, Colprim J. Anode hydrodynamics in bioelectrochemical systems. RSC Adv 2015. [DOI: 10.1039/c5ra11995b] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This study assesses the hydrodynamics in the anode compartment of a bioelectrochemical system (BES) when using different electrode materials (graphite rod, granular graphite, stainless steel mesh or graphite plate).
Collapse
Affiliation(s)
- Albert Vilà-Rovira
- LEQUiA
- Institute of the Environment
- University of Girona
- E-17071 Girona
- Spain
| | - Sebastià Puig
- LEQUiA
- Institute of the Environment
- University of Girona
- E-17071 Girona
- Spain
| | - M. Dolors Balaguer
- LEQUiA
- Institute of the Environment
- University of Girona
- E-17071 Girona
- Spain
| | - Jesús Colprim
- LEQUiA
- Institute of the Environment
- University of Girona
- E-17071 Girona
- Spain
| |
Collapse
|
24
|
Wang G, Chu J, Noorman H, Xia J, Tang W, Zhuang Y, Zhang S. Prelude to rational scale-up of penicillin production: a scale-down study. Appl Microbiol Biotechnol 2014; 98:2359-69. [DOI: 10.1007/s00253-013-5497-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 12/19/2013] [Accepted: 12/22/2013] [Indexed: 12/16/2022]
|
25
|
Higbee RW, Giacomelli JJ, Wyczalkowski WR. Advanced impeller design: Anti-ragging impeller, ARI2. Chem Eng Res Des 2013. [DOI: 10.1016/j.cherd.2013.04.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|