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van den Berg L, Kirkland CM, Seymour JD, Codd SL, van Loosdrecht MCM, de Kreuk MK. Heterogeneous diffusion in aerobic granular sludge. Biotechnol Bioeng 2020; 117:3809-3819. [PMID: 32725888 PMCID: PMC7818175 DOI: 10.1002/bit.27522] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/10/2020] [Accepted: 07/23/2020] [Indexed: 01/21/2023]
Abstract
Aerobic granular sludge (AGS) technology allows simultaneous nitrogen, phosphorus, and carbon removal in compact wastewater treatment processes. To operate, design, and model AGS reactors, it is essential to properly understand the diffusive transport within the granules. In this study, diffusive mass transfer within full‐scale and lab‐scale AGS was characterized with nuclear magnetic resonance (NMR) methods. Self‐diffusion coefficients of water inside the granules were determined with pulsed‐field gradient NMR, while the granule structure was visualized with NMR imaging. A reaction‐diffusion granule‐scale model was set up to evaluate the impact of heterogeneous diffusion on granule performance. The self‐diffusion coefficient of water in AGS was ∼70% of the self‐diffusion coefficient of free water. There was no significant difference between self‐diffusion in AGS from full‐scale treatment plants and from lab‐scale reactors. The results of the model showed that diffusional heterogeneity did not lead to a major change of flux into the granule (<1%). This study shows that differences between granular sludges and heterogeneity within granules have little impact on the kinetic properties of AGS. Thus, a relatively simple approach is sufficient to describe mass transport by diffusion into the granules.
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Affiliation(s)
- Lenno van den Berg
- Department of Water Management, Delft University of Technology, Delft, The Netherlands
| | - Catherine M Kirkland
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Civil Engineering, Montana State University, Bozeman, Montana
| | - Joseph D Seymour
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Chemical and Biological Engineering, Montana State University, Bozeman, Montana
| | - Sarah L Codd
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, Montana
| | | | - Merle K de Kreuk
- Department of Water Management, Delft University of Technology, Delft, The Netherlands
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2
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Schmidt SI, Cuthbert MO, Schwientek M. Towards an integrated understanding of how micro scale processes shape groundwater ecosystem functions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 592:215-227. [PMID: 28319709 DOI: 10.1016/j.scitotenv.2017.03.047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 03/05/2017] [Accepted: 03/06/2017] [Indexed: 06/06/2023]
Abstract
Micro scale processes are expected to have a fundamental role in shaping groundwater ecosystems and yet they remain poorly understood and under-researched. In part, this is due to the fact that sampling is rarely carried out at the scale at which microorganisms, and their grazers and predators, function and thus we lack essential information. While set within a larger scale framework in terms of geochemical features, supply with energy and nutrients, and exchange intensity and dynamics, the micro scale adds variability, by providing heterogeneous zones at the micro scale which enable a wider range of redox reactions. Here we outline how understanding micro scale processes better may lead to improved appreciation of the range of ecosystems functions taking place at all scales. Such processes are relied upon in bioremediation and we demonstrate that ecosystem modelling as well as engineering measures have to take into account, and use, understanding at the micro scale. We discuss the importance of integrating faunal processes and computational appraisals in research, in order to continue to secure sustainable water resources from groundwater.
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Affiliation(s)
- Susanne I Schmidt
- Centre for Systems Biology, University of Birmingham, Birmingham, UK.
| | - Mark O Cuthbert
- Connected Waters Initiative Research Centre, UNSW Australia, 110 King Street, Manly Vale 2093, Australia; Department of Geography, University College London, Gower Street, London, WC1E 6BT, UK
| | - Marc Schwientek
- Center of Applied Geoscience, University of Tübingen, 72074 Tübingen, Germany
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3
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Continuum and discrete approach in modeling biofilm development and structure: a review. J Math Biol 2017; 76:945-1003. [PMID: 28741178 DOI: 10.1007/s00285-017-1165-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 07/04/2017] [Indexed: 12/21/2022]
Abstract
The scientific community has recognized that almost 99% of the microbial life on earth is represented by biofilms. Considering the impacts of their sessile lifestyle on both natural and human activities, extensive experimental activity has been carried out to understand how biofilms grow and interact with the environment. Many mathematical models have also been developed to simulate and elucidate the main processes characterizing the biofilm growth. Two main mathematical approaches for biomass representation can be distinguished: continuum and discrete. This review is aimed at exploring the main characteristics of each approach. Continuum models can simulate the biofilm processes in a quantitative and deterministic way. However, they require a multidimensional formulation to take into account the biofilm spatial heterogeneity, which makes the models quite complicated, requiring significant computational effort. Discrete models are more recent and can represent the typical multidimensional structural heterogeneity of biofilm reflecting the experimental expectations, but they generate computational results including elements of randomness and introduce stochastic effects into the solutions.
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4
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Guimerà X, Dorado AD, Bonsfills A, Gabriel G, Gabriel D, Gamisans X. Dynamic characterization of external and internal mass transport in heterotrophic biofilms from microsensors measurements. WATER RESEARCH 2016; 102:551-560. [PMID: 27423049 DOI: 10.1016/j.watres.2016.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 07/05/2016] [Accepted: 07/06/2016] [Indexed: 06/06/2023]
Abstract
Knowledge of mass transport mechanisms in biofilm-based technologies such as biofilters is essential to improve bioreactors performance by preventing mass transport limitation. External and internal mass transport in biofilms was characterized in heterotrophic biofilms grown on a flat plate bioreactor. Mass transport resistance through the liquid-biofilm interphase and diffusion within biofilms were quantified by in situ measurements using microsensors with a high spatial resolution (<50 μm). Experimental conditions were selected using a mathematical procedure based on the Fisher Information Matrix to increase the reliability of experimental data and minimize confidence intervals of estimated mass transport coefficients. The sensitivity of external and internal mass transport resistances to flow conditions within the range of typical fluid velocities over biofilms (Reynolds numbers between 0.5 and 7) was assessed. Estimated external mass transfer coefficients at different liquid phase flow velocities showed discrepancies with studies considering laminar conditions in the diffusive boundary layer near the liquid-biofilm interphase. The correlation of effective diffusivity with flow velocities showed that the heterogeneous structure of biofilms defines the transport mechanisms inside biofilms. Internal mass transport was driven by diffusion through cell clusters and aggregates at Re below 2.8. Conversely, mass transport was driven by advection within pores, voids and water channels at Re above 5.6. Between both flow velocities, mass transport occurred by a combination of advection and diffusion. Effective diffusivities estimated at different biofilm densities showed a linear increase of mass transport resistance due to a porosity decrease up to biofilm densities of 50 g VSS·L(-1). Mass transport was strongly limited at higher biofilm densities. Internal mass transport results were used to propose an empirical correlation to assess the effective diffusivity within biofilms considering the influence of hydrodynamics and biofilm density.
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Affiliation(s)
- Xavier Guimerà
- Department of Mining Engineering and Natural Resources, Universitat Politècnica de Catalunya, Avinguda de les Bases de Manresa 61-73, 08240, Manresa, Spain.
| | - Antonio David Dorado
- Department of Mining Engineering and Natural Resources, Universitat Politècnica de Catalunya, Avinguda de les Bases de Manresa 61-73, 08240, Manresa, Spain.
| | - Anna Bonsfills
- Department of Mining Engineering and Natural Resources, Universitat Politècnica de Catalunya, Avinguda de les Bases de Manresa 61-73, 08240, Manresa, Spain.
| | - Gemma Gabriel
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Esfera UAB, Campus Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain; Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Zaragoza, Spain.
| | - David Gabriel
- Department of Chemical Engineering, Universitat Autònoma de Barcelona, Edifici Q, 08193, Bellaterra, Barcelona, Spain.
| | - Xavier Gamisans
- Department of Mining Engineering and Natural Resources, Universitat Politècnica de Catalunya, Avinguda de les Bases de Manresa 61-73, 08240, Manresa, Spain.
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5
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Study of extracellular polymeric substances in the biofilms of a suspended biofilter for nitric oxide removal. Appl Microbiol Biotechnol 2016; 100:9733-9743. [DOI: 10.1007/s00253-016-7824-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/15/2016] [Accepted: 08/18/2016] [Indexed: 10/21/2022]
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6
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Li M, Li P, Du C, Sun L, Li B. Pilot-Scale Study of an Integrated Membrane-Aerated Biofilm Reactor System on Urban River Remediation. Ind Eng Chem Res 2016. [DOI: 10.1021/acs.iecr.6b00143] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Mei Li
- Collaborative
Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, P.R. China
| | - Peng Li
- Collaborative
Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, P.R. China
| | - Chunyu Du
- Collaborative
Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, P.R. China
| | - Linquan Sun
- Collaborative
Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, P.R. China
| | - Baoan Li
- Collaborative
Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, P.R. China
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7
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Wang X, Han J, Li K, Wang G, Hao M. Multi-layer composite mechanical modeling for the inhomogeneous biofilm mechanical behavior. J Bioinform Comput Biol 2016; 14:1650014. [PMID: 27122202 DOI: 10.1142/s0219720016500141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Experiments showed that bacterial biofilms are heterogeneous, for example, the density, the diffusion coefficient, and mechanical properties of the biofilm are different along the biofilm thickness. In this paper, we establish a multi-layer composite model to describe the biofilm mechanical inhomogeneity based on unified multiple-component cellular automaton (UMCCA) model. By using our model, we develop finite element simulation procedure for biofilm tension experiment. The failure limit and biofilm extension displacement obtained from our model agree well with experimental measurements. This method provides an alternative theory to study the mechanical inhomogeneity in biological materials.
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Affiliation(s)
- Xiaoling Wang
- * School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China.,† Harvard John A. Paulson School of Engineering and Applied Sciences, Faculty of Arts and Sciences Harvard University, Cambridge MA 02138, USA.,‡ Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, 15, Bei Si Huan Xi Lu, Beijing 100190, China
| | - Jingshi Han
- * School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China
| | - Kui Li
- * School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China
| | - Guoqing Wang
- * School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China
| | - Mudong Hao
- * School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China
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8
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Shanahan JW, Semmens MJ. Alkalinity and pH effects on nitrification in a membrane aerated bioreactor: an experimental and model analysis. WATER RESEARCH 2015; 74:10-22. [PMID: 25703659 DOI: 10.1016/j.watres.2014.12.055] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 11/21/2014] [Accepted: 12/29/2014] [Indexed: 06/04/2023]
Abstract
A nitrifying biofilm was grown in a laboratory-scale membrane aerated bioreactor (MABR) to calibrate and test a one-dimensional biofilm model incorporating chemical equilibria to calculate local pH values. A previously developed model (Shanahan and Semmens, 2004) based upon AQUASIM was modified to incorporate the impact of local pH changes within the biofilm on the kinetics of nitrification. Shielded microelectrodes were used to measure the concentration profiles of dissolved oxygen, ammonium, nitrate, and pH within the biofilm and the overlying boundary layer under actual operating conditions. Operating conditions were varied to assess the impact of bicarbonate loading (alkalinity), ammonium loading, and intra-membrane oxygen partial pressure on biofilm performance. Nitrification performance improved with increased ammonium and bicarbonate loadings over the range of operating conditions tested, but declined when the intra-membrane oxygen partial pressure was increased. Minor discrepancies between the measured and predicted concentration profiles within the biofilm were attributed to changes in biofilm density and vertical heterogeneities in biofilm structure not accounted for by the model. Nevertheless, predicted concentration profiles within the biofilm agreed well with experimental results over the range of conditions studied and highlight the fact that pH changes in the biofilm are significant especially in low alkalinity waters. The influent pH and buffer capacity of a wastewater may therefore have a significant impact on the performance of a membrane-aerated bioreactor with respect to nitrification, and nitrogen removal.
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Affiliation(s)
| | - Michael J Semmens
- Dept of Civil Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
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9
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Gonzo EE, Wuertz S, Rajal VB. The continuum heterogeneous biofilm model with multiple limiting substrate Monod kinetics. Biotechnol Bioeng 2014; 111:2252-64. [DOI: 10.1002/bit.25284] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 03/31/2014] [Accepted: 05/07/2014] [Indexed: 11/11/2022]
Affiliation(s)
- Elio Emilio Gonzo
- INIQUI (CONICET)-Facultad de Ingeniería; Universidad Nacional de Salta; Av. Bolivia 5150 Salta 4400 Argentina
| | - Stefan Wuertz
- School of Biological Sciences; Singapore Centre on Environmental Life Sciences Engineering (SCELSE); Nanyang Technological University; Singapore Singapore
- School of Civil and Environmental Engineering; Nanyang Technological University; Singapore Singapore
- Department of Civil and Environmental Engineering; University of California, Davis; Davis California
| | - Veronica B. Rajal
- INIQUI (CONICET)-Facultad de Ingeniería; Universidad Nacional de Salta; Av. Bolivia 5150 Salta 4400 Argentina
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10
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11
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Dey S, Mukherjee S. Performance study and kinetic modeling of hybrid bioreactor for treatment of bi-substrate mixture of phenol-m-cresol in wastewater: process optimization with response surface methodology. J Environ Sci (China) 2013; 25:698-709. [PMID: 23923778 DOI: 10.1016/s1001-0742(12)60096-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Performance of a hybrid reactor comprising of trickling filter (TF) and aeration tank (AT) unit was studied for biological treatment of wastewater containing mixture of phenol and m-cresol, using mixed microbial culture. The reactor was operated with hydraulic loading rates (HLR) and phenolics loading rates (PLR) between 0.222-1.078 m3/(m2 x day) and 0.900-3.456 kg/(m3 x day), respectively. The efficiency of substrate removal varied between 71%-100% for the range of HLR and PLR studied. The fixed film unit showed better substrate removal efficiency than the aeration tank and was more resistant to substrate inhibition. The kinetic parameters related to both units of the reactor were evaluated and their variation with HLR and PLR were monitored. It revealed the presence of substrate inhibition at high PLR both in TF and AT unit. The biofilm model established the substrate concentration profile within the film by solving differential equation of substrate mass transfer using boundary problem solver tool 'bvp4c' of MATLAB 7.1 software. Response surface methodology was used to design and optimize the biodegradation process using Design Expert 8 software, where phenol and m-cresol concentrations, residence time were chosen as input variables and percentage of removal was the response. The design of experiment showed that a quadratic model could be fitted best for the present experimental study. Significant interaction of the residence time with the substrate concentrations was observed. The optimized condition for operating the reactor as predicted by the model was 230 mg/L of phenol, 190 mg/L of m-cresol with residence time of 24.82 hr to achieve 99.92% substrate removal.
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Affiliation(s)
- Sudipta Dey
- Department of Biotechnology, Heritage Institute of Technology, Anandapur Chowbaga Road, Kolkata -700107, West Bengal, India.
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12
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Gonzo EE, Wuertz S, Rajal VB. Continuum heterogeneous biofilm model-A simple and accurate method for effectiveness factor determination. Biotechnol Bioeng 2012; 109:1779-90. [DOI: 10.1002/bit.24441] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 12/29/2011] [Accepted: 01/05/2012] [Indexed: 01/13/2023]
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13
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Celmer-Repin D, Hwang JH, Cicek N, Oleszkiewicz JA. Autotrophic nitrogen-removing biofilms on porous and non-porous membranes. ENVIRONMENTAL TECHNOLOGY 2010; 31:1391-1401. [PMID: 21121462 DOI: 10.1080/09593331003743112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The effective removal of nitrogen compounds from wastewater has become a critical issue for treatment plants as the awareness of their negative impact on the environment increased. Autotrophic nitrogen removal has become an interesting alternative to the more conventional heterotrophic processes, as it eliminates the need for an organic carbon addition to the source water and reduces biomass yields. Gas transfer membrane biofilm reactors (MBfR) for nitrification and hydrogen driven denitrification are of special interest as they combine membrane diffusers and biofilms, provide an efficient supply of necessary electron donor for autotrophic removal of ammonia and nitrate, extend solids retention times and retain biomass within the reactor. Subsequently, a wide range of MBfR, which vary based on the type of membrane material and membrane module configuration, are being tested for this purpose. This paper reviews the research to date and also discusses the challenges that still lay ahead before MBfR can be used at treatment plants.
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Affiliation(s)
- Dominika Celmer-Repin
- Water and Waste Department, City of Winnipeg, 1199 Pacific Avenue, Winnipeg, MB, Canada R3E 3S8
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14
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Garcia-Ochoa F, Gomez E, Santos VE, Merchuk JC. Oxygen uptake rate in microbial processes: An overview. Biochem Eng J 2010. [DOI: 10.1016/j.bej.2010.01.011] [Citation(s) in RCA: 183] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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15
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Górka A, Papciak D, Zamorska J, Antos D. The Influence of Biofilm on the Effectiveness of Ion Exchange Process. Ind Eng Chem Res 2008. [DOI: 10.1021/ie8002057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Anna Górka
- Department of Chemical Engineering and Processing and Department of Water Purification and Protection, Rzeszów University of Technology, al. Powstańcǒw Warszawy 6, 35-959 Rzeszǒw, Poland
| | - Dorota Papciak
- Department of Chemical Engineering and Processing and Department of Water Purification and Protection, Rzeszów University of Technology, al. Powstańcǒw Warszawy 6, 35-959 Rzeszǒw, Poland
| | - Justyna Zamorska
- Department of Chemical Engineering and Processing and Department of Water Purification and Protection, Rzeszów University of Technology, al. Powstańcǒw Warszawy 6, 35-959 Rzeszǒw, Poland
| | - Dorota Antos
- Department of Chemical Engineering and Processing and Department of Water Purification and Protection, Rzeszów University of Technology, al. Powstańcǒw Warszawy 6, 35-959 Rzeszǒw, Poland
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16
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Martínez Delgadillo SA, Cantú-Lozano D, Montalvo C, González Hernàndez J. Simultaneous Oxygen and Carbon Variation within an RBC Biofilm as Function of Different Operating Conditions. Ind Eng Chem Res 2008. [DOI: 10.1021/ie8005885] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sergio A. Martínez Delgadillo
- Departamento de Energía, Universidad Autónoma Metropolitana-Azcapotzalco, Avenida San Pablo 180, CP 02200, México D.F., México, División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Orizaba, Oriente 9, 852, Col. E. Zapata, Orizaba, 94320 Mexico, and CIMAV-Centro de Investigación en Materiales Avanzado, Miguel de Cervantes 120, Complejo Industrial 31109, Chihuahua, México
| | - Denis Cantú-Lozano
- Departamento de Energía, Universidad Autónoma Metropolitana-Azcapotzalco, Avenida San Pablo 180, CP 02200, México D.F., México, División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Orizaba, Oriente 9, 852, Col. E. Zapata, Orizaba, 94320 Mexico, and CIMAV-Centro de Investigación en Materiales Avanzado, Miguel de Cervantes 120, Complejo Industrial 31109, Chihuahua, México
| | - Carlos Montalvo
- Departamento de Energía, Universidad Autónoma Metropolitana-Azcapotzalco, Avenida San Pablo 180, CP 02200, México D.F., México, División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Orizaba, Oriente 9, 852, Col. E. Zapata, Orizaba, 94320 Mexico, and CIMAV-Centro de Investigación en Materiales Avanzado, Miguel de Cervantes 120, Complejo Industrial 31109, Chihuahua, México
| | - Jesús González Hernàndez
- Departamento de Energía, Universidad Autónoma Metropolitana-Azcapotzalco, Avenida San Pablo 180, CP 02200, México D.F., México, División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Orizaba, Oriente 9, 852, Col. E. Zapata, Orizaba, 94320 Mexico, and CIMAV-Centro de Investigación en Materiales Avanzado, Miguel de Cervantes 120, Complejo Industrial 31109, Chihuahua, México
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Celmer D, Oleszkiewicz JA, Cicek N. Impact of shear force on the biofilm structure and performance of a membrane biofilm reactor for tertiary hydrogen-driven denitrification of municipal wastewater. WATER RESEARCH 2008; 42:3057-3065. [PMID: 18396310 DOI: 10.1016/j.watres.2008.02.031] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 02/19/2008] [Accepted: 02/20/2008] [Indexed: 05/26/2023]
Abstract
Hydrogen-driven denitrification using a hollow-fiber membrane biofilm reactor (MBfR) was evaluated for operation in tertiary wastewater treatment. Specific objectives were to evaluate the impact of different levels of shearing stress caused by mixing and nitrogen sparging on the biofilm structure and denitrification rates. Applying high shear force proved to be effective in improving denitrification rates by reducing the thickness of the biofilm. With intensive mixing a biofilm thickness of approximately 800 microm was maintained, while additional nitrogen sparging could further reduce the biofilm thickness to approximately 300 microm. The highest denitrification rates of 0.93 gN/m(2)d were obtained when biofilm thickness was lower than 500 microm. Lower extracellular polymeric substances (EPS) accumulation and carbohydrates to protein ratio observed in thinner biofilms allowed for higher nitrate removal in the system. No significant sloughing of biomass or change in total and soluble COD in the final effluent was observed under steady-state conditions.
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Affiliation(s)
- D Celmer
- Department of Civil Engineering, University of Manitoba, 15 Gillson Street, Winnipeg, Canada R3T 5V6.
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19
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McLean JS, Ona ON, Majors PD. Correlated biofilm imaging, transport and metabolism measurements via combined nuclear magnetic resonance and confocal microscopy. ISME JOURNAL 2007; 2:121-31. [PMID: 18253132 DOI: 10.1038/ismej.2007.107] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Bacterial biofilms are complex, three-dimensional communities found nearly everywhere in nature and are also associated with many human diseases. Detailed metabolic information is critical to understand and exploit beneficial biofilms as well as combat antibiotic-resistant, disease-associated forms. However, most current techniques used to measure temporal and spatial metabolite profiles in these delicate structures are invasive or destructive. Here, we describe imaging, transport and metabolite measurement methods and their correlation for live, non-invasive monitoring of biofilm processes. This novel combination of measurements is enabled by the use of an integrated nuclear magnetic resonance (NMR) and confocal laser scanning microscope (CLSM). NMR methods provide macroscopic structure, metabolic pathway and rate data, spatially resolved metabolite concentrations and water diffusion profiles within the biofilm. In particular, current depth-resolved spectroscopy methods are applied to detect metabolites in 140-190 nl volumes within biofilms of the dissimilatory metal-reducing bacterium Shewanella oneidensis strain MR-1 and the oral bacterium implicated in caries disease, Streptococcus mutans strain UA159. The perfused sample chamber also contains a transparent optical window allowing for the collection of complementary fluorescence information using a unique, in-magnet CLSM. In this example, the entire three-dimensional biofilm structure was imaged using magnetic resonance imaging. This was then correlated to a fluorescent CLSM image by employing a green fluorescent protein reporter construct of S. oneidensis. Non-invasive techniques such as described here, which enable measurements of dynamic metabolic processes, especially in a depth-resolved fashion, are expected to advance our understanding of processes occurring within biofilm communities.
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Affiliation(s)
- Jeffrey S McLean
- Environmental Microbial Genomics, J. Craig Venter Institute, 111 49 N Torrey Pines Rd, Suite 220, La Jolla, CA 92037, USA.
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Li XZ, Hauer B, Rosche B. Single-species microbial biofilm screening for industrial applications. Appl Microbiol Biotechnol 2007; 76:1255-62. [PMID: 17653709 DOI: 10.1007/s00253-007-1108-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 06/28/2007] [Accepted: 06/29/2007] [Indexed: 01/15/2023]
Abstract
While natural microbial biofilms often consist of multiple species, single-species biofilms are of great interest to biotechnology. The current study evaluates biofilm formation for common industrial and laboratory microorganisms. A total of 68 species of biosafety level one bacteria and yeasts from over 40 different genera and five phyla were screened by growing them in microtiter plates and estimating attached biomass by crystal violet staining. Most organisms showed biofilm formation on surfaces of polystyrene within 24 h. By changing a few simple conditions such as substratum characteristics, inoculum and nutrient availability, 66 strains (97%) demonstrated biofilm formation under at least one of the experimental conditions and over half of these strains were classified as strong biofilm formers, potentially suitable as catalysts in biofilm applications. Many non-motile bacteria were also strong biofilm formers. Biofilm morphologies were visualized for selected strains. A model organism, Zymomonas mobilis, easily established itself as a biofilm on various reactor packing materials, including stainless steel.
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Affiliation(s)
- Xuan Zhong Li
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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González-Brambila M, Monroy O, López-Isunza F. Experimental and theoretical study of membrane-aerated biofilm reactor behavior under different modes of oxygen supply for the treatment of synthetic wastewater. Chem Eng Sci 2006. [DOI: 10.1016/j.ces.2006.03.049] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gomez E, Santos V, Alcon A, Garcia-Ochoa F. Oxygen transport rate on Rhodococcus erythropolis cultures: Effect on growth and BDS capability. Chem Eng Sci 2006. [DOI: 10.1016/j.ces.2006.02.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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