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Guo S, Yu W, Zhao H, Lai C, Bian S, Jin P, Liang S, Yuan S, Huang L, Wang S, Duan H, Wang F, Yang J. Numerical simulation to optimize passive aeration strategy for semi-aerobic landfill. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 171:676-685. [PMID: 37866111 DOI: 10.1016/j.wasman.2023.10.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/05/2023] [Accepted: 10/13/2023] [Indexed: 10/24/2023]
Abstract
Passive aeration has been proven to be efficient for oxygen supply in landfill. The combination of passive aeration and semi-aerobic landfill offers a cost-effective and energy-efficient approach to solid waste (SW) treatment. However, determining the optimal strategy for this combination has remained unclear. This study aimed to investigate the strategy of passive aeration in a semi-aerobic landfill using numerical simulation methods. A model coupled hydrodynamic model and compartment model for degradation of SW was implemented. The accuracy was well validated by comparing measured and simulated results in a pilot-scale landfill. Compared with natural convection, passive aeration by funnel caps could increase air input by 20 %. By simulating volumetric fraction distribution of CO2, CH4 and O2 in landfill, an orthogonal experiment including 4 factors was designed to identify that the diameter of tubes (DT), the spacing between tubes (ST) and the landfill depth (LD) have substantial impacts on aerobic zone ratio (AZR) of landfill. But the diameter of gas ports (DGP) has an indiscernible effect. The optimized factors were determined to be as follows: DT = 0.3 m, ST = 15.0 m, DGP = 0.05 m, and LD = 4.0 m, under which the semi-aerobic landfill could enhance SW degradation. Large diameter and spacing of tubes are favorable to improve the AZR at the top of the landfill, and the aerobic zone mainly exists near the ventilation tubes. These findings contribute to the development of more efficient and sustainable solid waste treatment strategies in semi-aerobic landfill.
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Affiliation(s)
- Shuai Guo
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Wenbo Yu
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei 430074, China; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China.
| | - Hongyang Zhao
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Changfei Lai
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Shijie Bian
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Pan Jin
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Sha Liang
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei 430074, China; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China
| | - Shushan Yuan
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei 430074, China; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China
| | - Liang Huang
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei 430074, China; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China
| | - Songlin Wang
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei 430074, China; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China
| | - Huabo Duan
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei 430074, China; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China
| | - Feifei Wang
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Jiakuan Yang
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei 430074, China; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China
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Norouzi‐Firouz H, Sarrafzadeh M, Zarghami R, Moshiri‐Tabrizi I. A coupled hydrodynamic‐biokinetic simulation of three‐phase flow in an oxidation ditch using
CFD. CAN J CHEM ENG 2022. [DOI: 10.1002/cjce.24095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Hossein Norouzi‐Firouz
- UNESCO Chair on Water Reuse, School of Chemical Engineering, College of Engineering University of Tehran Tehran Iran
| | - Mohammad‐Hossein Sarrafzadeh
- UNESCO Chair on Water Reuse, School of Chemical Engineering, College of Engineering University of Tehran Tehran Iran
| | - Reza Zarghami
- UNESCO Chair on Water Reuse, School of Chemical Engineering, College of Engineering University of Tehran Tehran Iran
- Process Design and Simulation Research Centre, School of Chemical Engineering, College of Engineering University of Tehran Tehran Iran
| | - Iman Moshiri‐Tabrizi
- UNESCO Chair on Water Reuse, School of Chemical Engineering, College of Engineering University of Tehran Tehran Iran
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3
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Xu Q, Wan Y, Wu Q, Xiao K, Yu W, Liang S, Zhu Y, Hou H, Liu B, Hu J, Yang Y, Yang J. An efficient hydrodynamic-biokinetic model for the optimization of operational strategy applied in a full-scale oxidation ditch by CFD integrated with ASM2. WATER RESEARCH 2021; 193:116888. [PMID: 33581403 DOI: 10.1016/j.watres.2021.116888] [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: 09/10/2020] [Revised: 12/20/2020] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
Oxidation ditches (ODs) are often used for wastewater treatment. However, limitations of ODs like high energy expenditure and increased sludge sedimentation hinder its wide application. In this study, the computational fluid dynamics (CFD) model integrated with Activated Sludge Model No. 2 (ASM2) was proposed and applied in a full-scale OD. The integrated model provided heterogeneous information on the characteristics of hydrodynamics and biokinetics of OD, especially with respect to the simulation of total phosphorus removal by CFD-ASM2 integration model for the first time. The simulated values of flow velocities, suspended solids (SS), dissolved oxygen, chemical oxygen demand, total nitrogen, ammonium nitrogen, and total phosphorus concentrations were well validated with the measured results, with the standard deviation errors of less than 5.56%, 0.28%, 0.74%, 7.39%, 3.17%, 5.27%, and 7.40%, respectively. Based on the integrated model, four different operational strategies were simulated. The proposed operational strategy of operating 7 surface aerators and 10 submerged impellers not only met the standard discharge requirements (GB 18918-2002) but also consumed less energy by 22.3%, compared with the original strategy of operating 9 surface aerators and 13 submerged impellers. Meanwhile, this proposed operational strategy also reduced the SS concentrations in the second and fourth channels, which was beneficial to elimination of sludge sedimentation. Moreover, the proposed operational strategy was successfully applied and validated in full-scale OD. The foregoing results collectively suggest that the CFD-AMS2 integration model is numerically capable to optimize the operational strategy of ODs.
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Affiliation(s)
- Qi Xu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, Hubei, 430074, China; Changjiang Institute of Survey, Planning, Design and Research, Jiefang Avenue 1863, Wuhan, Hubei, 430010, China
| | - Yanlei Wan
- Changjiang Institute of Survey, Planning, Design and Research, Jiefang Avenue 1863, Wuhan, Hubei, 430010, China
| | - Qiongxiang Wu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, Hubei, 430074, China
| | - Keke Xiao
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, Hubei, 430074, China.
| | - Wenbo Yu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, Hubei, 430074, China
| | - Sha Liang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, Hubei, 430074, China
| | - Yuwei Zhu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, Hubei, 430074, China
| | - Huijie Hou
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, Hubei, 430074, China
| | - Bingchuan Liu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, Hubei, 430074, China
| | - Jingping Hu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, Hubei, 430074, China
| | - Yin Yang
- Smith School of Enterprise and the Environment, University of Oxford, South Parks Road, Oxford OX1 3QY, United Kingdom
| | - Jiakuan Yang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, Hubei, 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, Luoyu Road 1037, Wuhan, Hubei, 430074, China; State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, Hubei, 430074, China.
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4
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Xu X, Wei W, Liu F, Wei W, Liu Z. Experimental study on aeration efficiency in a pilot‐scale decelerated oxidation ditch equipped with fine bubble diffusers and impellers. CAN J CHEM ENG 2020. [DOI: 10.1002/cjce.23919] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Xiaofei Xu
- R&D Institute of Fluid and Powder Engineering Dalian University of Technology Dalian China
| | - Wenze Wei
- R&D Institute of Fluid and Powder Engineering Dalian University of Technology Dalian China
| | - Fengxia Liu
- R&D Institute of Fluid and Powder Engineering Dalian University of Technology Dalian China
| | - Wei Wei
- R&D Institute of Fluid and Powder Engineering Dalian University of Technology Dalian China
| | - Zhijun Liu
- R&D Institute of Fluid and Powder Engineering Dalian University of Technology Dalian China
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Three-dimensional simulation of a secondary circular settling tank: flow pattern and sedimentation process. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2020. [DOI: 10.1007/s43153-020-00030-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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6
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Xu Q, Xiao K, Wu Q, Wang H, Liang S, Yu W, Tao S, Hou H, Liu B, Hu J, Yang J. The optimization on distributions of flow field and suspended solids in a full-scale high-rate clarifier using computational fluid dynamics. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2020.107489] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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7
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Cui Y, Ravnik J, Steinmann P, Hriberšek M. Settling characteristics of nonspherical porous sludge flocs with nonhomogeneous mass distribution. WATER RESEARCH 2019; 158:159-170. [PMID: 31035193 DOI: 10.1016/j.watres.2019.04.017] [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: 12/05/2018] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
The paper reports on the development of an advanced Lagrangian particle tracking model of sludge flocs that takes into account its nonspherical shape, the internal porosity and permeability, as well as the nonhomogenous mass distribution. The floc shapes, sizes and free settling velocities are determined based on the experimental measurement of settling sludge flocs originating from a wastewater treatment plant. Based on the floc shape characterization, a prolate axisymmetric ellipsoid is selected as the modelled sludge particle. In order to determine the main particle characteristics, e.g. the internal porosity, the density and the flow permeability, a Lagrangian particle tracking model is developed based on Brenner's drag model for a prolate axisymmetric ellipsoid and a buoyancy force model for a porous particle. The model is implemented for numerical simulations of the free settling process. The obtained floc characteristics are presented in the form of a two-part polynomial fitting curve, which can be used to model floc characteristics. The values of settling velocities of flocs computed by the model show very good agreement with experimental results. Futhermore, as the internal structure of a floc is seldom uniform, the nonhomogeneous mass distribution is considered, influencing the rotational and translational motions of the settling flocs. The nonhomogeneous mass distribution is introduced into the floc settling model. The parametric analyses of different barycentre offsets and shear rates are performed, and their influences on the free settling velocity are evaluated. The presented modelling approach can also be applied to flocculent settling of alum and other flocs in drinking water treatment plants. The developed Lagrangian model is suitable for use as a point source within the framework of Eulerian flow computations, and is solved as a two-phase flow model with a suitable Computational Fluid Dynamics code.
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Affiliation(s)
- Yan Cui
- Chair of Applied Mechanics, Friedrich-Alexander Universität Erlangen-Nürnberg, Paul-Gordan-Str. 3, D-91052, Erlangen, Germany.
| | - Jure Ravnik
- Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, SI-2000, Maribor, Slovenia.
| | - Paul Steinmann
- Chair of Applied Mechanics, Friedrich-Alexander Universität Erlangen-Nürnberg, Paul-Gordan-Str. 3, D-91052, Erlangen, Germany.
| | - Matjaž Hriberšek
- Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, SI-2000, Maribor, Slovenia.
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8
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Sánchez F, Rey H, Viedma A, Nicolás-Pérez F, Kaiser AS, Martínez M. CFD simulation of fluid dynamic and biokinetic processes within activated sludge reactors under intermittent aeration regime. WATER RESEARCH 2018; 139:47-57. [PMID: 29626729 DOI: 10.1016/j.watres.2018.03.067] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/10/2018] [Accepted: 03/27/2018] [Indexed: 06/08/2023]
Abstract
Due to the aeration system, biological reactors are the most energy-consuming facilities of convectional WWTPs. Many biological reactors work under intermittent aeration regime; the optimization of the aeration process (air diffuser layout, air flow rate per diffuser, aeration length …) is necessary to ensure an efficient performance; satisfying the effluent requirements with the minimum energy consumption. This work develops a CFD modelling of an activated sludge reactor (ASR) which works under intermittent aeration regime. The model considers the fluid dynamic and biological processes within the ASR. The biological simulation, which is transient, takes into account the intermittent aeration regime. The CFD modelling is employed for the selection of the aeration system of an ASR. Two different aeration configurations are simulated. The model evaluates the aeration power consumption necessary to satisfy the effluent requirements. An improvement of 2.8% in terms of energy consumption is achieved by modifying the air diffuser layout. An analysis of the influence of the air flow rate per diffuser on the ASR performance is carried out. The results show a reduction of 14.5% in the energy consumption of the aeration system when the air flow rate per diffuser is reduced. The model provides an insight into the aeration inefficiencies produced within ASRs.
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Affiliation(s)
- F Sánchez
- Departamento de Ingeniería Térmica y de Fluidos, Universidad Politécnica de Cartagena, Dr. Fleming, s/n, 30202, Cartagena, Spain
| | - H Rey
- Instituto de Ingeniería del Agua y Medio Ambiente, Universitat Politècnica de València, Camino de Vera 14, P.O. Box 46022, Valencia, Spain; Prointec S.A., C/ De San Julián nº1, 28108 Alcobendas, Madrid, Spain.
| | - A Viedma
- Departamento de Ingeniería Térmica y de Fluidos, Universidad Politécnica de Cartagena, Dr. Fleming, s/n, 30202, Cartagena, Spain
| | - F Nicolás-Pérez
- Lynx Simulations S.L., Calderón de la Barca 31, 30180 Bullas, Spain
| | - A S Kaiser
- Departamento de Ingeniería Térmica y de Fluidos, Universidad Politécnica de Cartagena, Dr. Fleming, s/n, 30202, Cartagena, Spain
| | - M Martínez
- Prointec S.A., C/ De San Julián nº1, 28108 Alcobendas, Madrid, Spain
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9
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Xu D, Liu S, Chen Q, Ni J. Microbial community compositions in different functional zones of Carrousel oxidation ditch system for domestic wastewater treatment. AMB Express 2017; 7:40. [PMID: 28205101 PMCID: PMC5311017 DOI: 10.1186/s13568-017-0336-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 01/31/2017] [Indexed: 11/10/2022] Open
Abstract
The microbial community diversity in anaerobic-, anoxic- and oxic-biological zones of a conventional Carrousel oxidation ditch system for domestic wastewater treatment was systematically investigated. The monitored results of the activated sludge sampled from six full-scale WWTPs indicated that Proteobacteria, Chloroflexi, Bacteroidetes, Actinobacteria, Verrucomicrobia, Acidobacteria and Nitrospirae were dominant phyla, and Nitrospira was the most abundant and ubiquitous genus across the three biological zones. The anaerobic-, anoxic- and oxic-zones shared approximately similar percentages across the 50 most abundant genera, and three genera (i.e. uncultured bacterium PeM15, Methanosaeta and Bellilinea) presented statistically significantly differential abundance in the anoxic-zone. Illumina high-throughput sequences related to ammonium oxidizer organisms and denitrifiers with top50 abundance in all samples were Nitrospira, uncultured Nitrosomonadaceae, Dechloromonas, Thauera, Denitratisoma, Rhodocyclaceae (norank) and Comamonadaceae (norank). Moreover, environmental variables such as water temperature, water volume, influent ammonium nitrogen, influent chemical oxygen demand (COD) and effluent COD exhibited significant correlation to the microbial community according to the Monte Carlo permutation test analysis (p < 0.05). The abundance of Nitrospira, uncultured Nitrosomonadaceae and Denitratisoma presented strong positive correlations with the influent/effluent concentration of COD and ammonium nitrogen, while Dechloromonas, Thauera, Rhodocyclaceae (norank) and Comamonadaceae (norank) showed positive correlations with water volume and temperature. The established relationship between microbial community and environmental variables in different biologically functional zones of the six representative WWTPs at different geographical locations made the present work of potential use for evaluation of practical wastewater treatment processes.
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Meister M, Winkler D, Rezavand M, Rauch W. Integrating hydrodynamics and biokinetics in wastewater treatment modelling by using smoothed particle hydrodynamics. Comput Chem Eng 2017. [DOI: 10.1016/j.compchemeng.2016.12.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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11
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Yang M, Wei Y, Zheng X, Wang F, Yuan X, Liu J, Luo N, Xu R, Yu D, Fan Y. CFD simulation and optimization of membrane scouring and nitrogen removal for an airlift external circulation membrane bioreactor. BIORESOURCE TECHNOLOGY 2016; 219:566-575. [PMID: 27540633 DOI: 10.1016/j.biortech.2016.07.139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/13/2016] [Accepted: 07/14/2016] [Indexed: 06/06/2023]
Abstract
Cost-effective membrane fouling control and nitrogen removal performance are of great concern in airlift external circulation membrane bioreactors (AEC-MBRs). Computational fluid dynamics (CFD) model incorporating sub-models of bio-kinetics, oxygen transfer and sludge rheology was developed for the cost-effective optimization of a lab-scale AEC-MBR. The model was calibrated and validated by extensive measurements of water velocities and water quality parameters in the AEC-MBR. The validated results demonstrated that the optimized height of gas-liquid dispersion was at around 300mm. The shear stress on membrane surface was equalized and had an average value of 1.2Pa under an air flowrate of 1.0m(3)h(-1). The model further revealed that the high nitrogen removal efficiency (>90%) was achieved due to the high recirculation ratio driven by airlift force without destroying the oxygen deprivation and enrichment in the anoxic and oxic zone, respectively.
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Affiliation(s)
- Min Yang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Yuansong Wei
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Xiang Zheng
- School of Environment and Nature Resources, Renmin University of China, Beijing 100872, China
| | - Fang Wang
- School of Energy and Power Engineering, Beihang University, Beijing 100191, China
| | - Xing Yuan
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jibao Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Nan Luo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rongle Xu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dawei Yu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaobo Fan
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
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12
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Karpinska AM, Bridgeman J. CFD-aided modelling of activated sludge systems - A critical review. WATER RESEARCH 2016; 88:861-879. [PMID: 26615385 DOI: 10.1016/j.watres.2015.11.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/01/2015] [Accepted: 11/02/2015] [Indexed: 06/05/2023]
Abstract
Nowadays, one of the major challenges in the wastewater sector is the successful design and reliable operation of treatment processes, which guarantee high treatment efficiencies to comply with effluent quality criteria, while keeping the investment and operating cost as low as possible. Although conceptual design and process control of activated sludge plants are key to ensuring these goals, they are still based on general empirical guidelines and operators' experience, dominated often by rule of thumb. This review paper discusses the rationale behind the use of Computational Fluid Dynamics (CFD) to model aeration, facilitating enhancement of treatment efficiency and reduction of energy input. Several single- and multiphase approaches commonly used in CFD studies of aeration tank operation, are comprehensively described, whilst the shortcomings of the modelling assumptions imposed to evaluate mixing and mass transfer in AS tanks are identified and discussed. Examples and methods of coupling of CFD data with biokinetics, accounting for the actual flow field and its impact on the oxygen mass transfer and yield of the biological processes occurring in the aeration tanks, are also critically discussed. Finally, modelling issues, which remain unaddressed, (e.g. coupling of the AS tank with secondary clarifier and the use of population balance models to simulate bubbly flow or flocculation of the activated sludge), are also identified and discussed.
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Affiliation(s)
- Anna M Karpinska
- School of Civil Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
| | - John Bridgeman
- School of Civil Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
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Fan J, Ji F, Xu X, Wang Y, Yan D, Xu X, Chen Q, Xiong J, He Q. Prediction of the effect of fine grit on the MLVSS/MLSS ratio of activated sludge. BIORESOURCE TECHNOLOGY 2015; 190:51-56. [PMID: 25919937 DOI: 10.1016/j.biortech.2015.04.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/10/2015] [Accepted: 04/12/2015] [Indexed: 06/04/2023]
Abstract
This paper investigated the suspension properties of fine grit with different particle sizes in a bioreactor and developed a model to predict its effect on the ratio of mixed liquor volatile suspended solids to the mixed liquor suspended solids (MLVSS/MLSS) of activated sludge. The experimental results revealed that a smaller particle size corresponds to a larger suspension ratio, defined as the proportion of fine grit brought in by influent that is suspended in the activated sludge, and a smaller MLVSS/MLSS ratio. The model demonstrated that the effect of fine grit on the MLVSS/MLSS ratio is related to the fine grit concentration and chemical oxygen demand in influent and the observed sludge yield. However, fine grit has no influence on the activity of microorganisms. Wastewater treatment plants (WWTPs) can adjust MLSS based on the MLVSS/MLSS ratio to ensure the stability of MLVSS, which can achieve the stable operation of WWTPs.
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Affiliation(s)
- Jianping Fan
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, China
| | - Fangying Ji
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, China.
| | - Xiaoyi Xu
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, China
| | - Ying Wang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, China
| | - Dachao Yan
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, China
| | - Xuan Xu
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, China
| | - Qingkong Chen
- School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing 400074, China
| | - Jingzhong Xiong
- The Southwest Subsidiary Company of China Airport Construction Group Corporation, Chengdu 610202, China
| | - Qiang He
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, China
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