biofilm model Articles

  • A framework for good biofilm reactor modeling practice (GBRMP)

    A researcher or practitioner can employ a biofilm model to gain insight into what controls the performance of a biofilm process and for optimizing its performance. While a wide range of biofilm-modeling platforms is available, a good strategy is to choose the simplest model that includes sufficient components and processes to address the modeling goal. In most cases, a one-dimensional biofilm ...


    By IWA Publishing

  • Biofilm carrier migration model describes reactor performance

    The accuracy of a biofilm reactor model depends on the extent to which physical system conditions (particularly bulk-liquid hydrodynamics and their influence on biofilm dynamics) deviate from the ideal conditions upon which the model is based. It follows that an improved capacity to model a biofilm reactor does not necessarily rely on an improved biofilm model, but does rely on an improved ...


    By IWA Publishing

  • Modelling ammonium-oxidizing population shifts in a biofilm reactor

    The dynamic reactor behaviour of a nitrifying inverse turbulent bed reactor, operated at varying loading rate, was described with a one-dimensional two-step nitrification biofilm model. In contrast with conventional biofilm models, this model includes the competition between two genetically different populations of ammonia-oxidizing bacteria (AOB), besides nitrite-oxidizing bacteria (NOB). ...


    By IWA Publishing

  • Considering microbial and aggregate heterogeneity in biofilm reactor models: how far do we need to go?

    A model describing a given system should be as simple as possible – but not simpler. The appropriate level of complexity depends both on the type of system and on the intended use of the model. This paper addresses the critical question of which purposes justify increased complexity of biofilm (reactor) models. Additional model features compared to conventional models considered are: (1) the ...


    By IWA Publishing

  • Development of a simplified model for the fixed biofilm reactor

    A simplified fixed biofilm model was developed to formulate the relationship between the substrate concentrations at both the entry and exit, at the biofilm–liquid interface and at the biofilm attached surface along with average substrate flux in the biofilm, substrate flux at the biofilm–liquid interface and effective biofilm thickness. The model considered the substrate mass transport ...


    By IWA Publishing

  • Effective dispersion in channelled biofilms

    Heterogeneous biofilms may arise because of non-uniform biofilm growth. When considering multiple-scale problems involving biofilms, a direct simulation of the flow in the heterogeneous biofilm is not tractable. This calls for an averaged description of the flow and transport in such heterogeneous biofilms. This paper presents a theoretical derivation of the transport equations in such ...


    By Inderscience Publishers

  • Modeling phototrophic biofilms in a plug-flow reactor

    The use of phototrophic biofilms in wastewater treatment has been recognized as a potential option for development of new reactor configurations. For better understanding of these systems, a numerical model was developed including relevant microbial processes. As a novelty, this model was implemented in COMSOL Multiphysics, a modern computational environment for complex dynamic models. A ...


    By IWA Publishing

  • Systematic evaluation of biofilm models for engineering practice: components and critical assumptions

    Biofilm models are valuable tools for the design and evaluation of biofilm-based processes despite several uncertainties including the dynamics and rate of biofilm detachment, concentration gradients external to the biofilm surface, and undefined biofilm reactor model calibration protocol. The present investigation serves to (1) systematically evaluate critical biofilm model assumptions and ...


    By IWA Publishing

  • Experimental evaluation of the nitrite sensitivity coefficient in granular anammox biomass

    Nitrite is widely reported to inhibit anammox activity and growth. One modeling approach for nitrite impairment of anammox growth is the use of a nitrite sensitivity coefficient which increases the endogenous decay coefficient of anammox bacteria proportionally to nitrite concentration. The objective of this study was to measure nitrite concentration profiles within active anammox granules ...


    By IWA Publishing

  • An innovative approach for modeling aerobic granular sludge processes. Proceedings WEFTEC.17

    Abstract: An innovative biofilm model has been developed that allows modeling of a granular sludge sequencing batch reactor (GSBR) in a single tank without the need for a separate variable volume tank and a recycle stream. The model has a variable volume, supports separate or simultaneous feeding and effluent discharge, predicts the biofilm thickness without being constrained by a maximum ...


    By inCTRL Solutions Inc.

  • A methodology to assess the effects of biofilm roughness on substrate fluxes using image analysis, substrate profiling, and mathematical modelling

    We present a novel approach, based on image analysis and modelling, to study the impact of morphological variability (roughness) and fluid dynamics on substrate mass fluxes in biofilms. Specifically, we used this method to assess substrate fluxes in counter-diffusional autotrophic biofilms in a hydrogen-based membrane biofilm reactor. The physical structure of the biofilm was determined in ...


    By IWA Publishing

  • An experimentally validated immersed boundary model of fluid–biofilm interaction

    Biofllms are colonies of microorganisms that live on wetted surfaces in a matrix consisting of polysaccharides, proteins, and nucleic acids. According to the National Institute of Health (NIH), biofilms play a role in over 80 percent of microbial infections in the body and these infections are remarkably difficult to treat with antimicrobial compounds. The objective here is to understand and ...


    By IWA Publishing

  • Cellular automata-based modelling and simulation of biofilm structure on multi-core computers

    The article presents a mathematical model of biofilm growth for aerobic biodegradation of a toxic carbonaceous substrate. Modelling of biofilm growth has fundamental significance in numerous processes of biotechnology and mathematical modelling of bioreactors. The process following double-substrate kinetics with substrate inhibition proceeding in a biofilm has not been modelled so far by means ...


    By IWA Publishing

  • The role of homoacetogenic bacteria as efficient hydrogen scavengers in microbial electrochemical cells (MXCs)

    We evaluated the consumption of hydrogen gas at the anode of a microbial electrolysis cell (MEC) and characterized the significance of new interactions between anode respiring bacteria (ARB) and homo-acetogens. We demonstrated the significance of biofilm limitation for direct consumption of H2 over acetate by ARB, using the deep biofilm model. Selective inhibition of the major competing hydrogen ...


    By IWA Publishing

  • Mathematical modelling of biofilms and biofilm reactors for engineering design

    Mathematical models are critical to modern environmental biotechnology—both in research and in the engineering practice. Wastewater treatment plant (WWTP) simulators are used by consulting engineers and WWTP operators when planning, designing, optimizing, and evaluating the unit processes that comprise municipal and industrial WWTPs. Many WWTP simulators have been expanded to include a submerged ...


    By IWA Publishing

  • Modelling clogging and biofilm detachment in sponge carrier media

    Sponge carrier media provide a large surface area for biofilm support; however, little information is known about how to model their dual nature as a moving bed and as porous media. To investigate the interaction of mass transfer and detachment with bio-clogging, a novel biofilm model framework was built based on individual-based modelling, and hydrodynamics were modelled using the lattice ...


    By IWA Publishing

  • Experimental evaluation of the nitrite sensitivity coefficient in granular anammox biomass. Water Science & Technology

    Abstract: Nitrite is widely reported to inhibit anammox activity and growth. One modeling approach for nitrite impairment of anammox growth is the use of a nitrite sensitivity coefficient which increases the endogenous decay coefficient of anammox bacteria proportionally to nitrite concentration. The objective of this study was to measure nitrite concentration profiles within active anammox ...


    By inCTRL Solutions Inc.

  • Mathematical model of biofilm induced calcite precipitation

    Microbially modulated carbonate precipitation is a fundamentally important phenomenon of both engineered and natural environments. In this paper, we propose a mixture model for biofilm induced calcite precipitation. The model consists of three phases – calcite, biofilm and solvent – which satisfy conservation of mass and momentum laws with addition of a free energy of mixing. The model also ...


    By IWA Publishing

  • From biofilm ecology to reactors: a focused review

    Biofilms are complex biostructures that appear on all surfaces that are regularly in contact with water. They are structurally complex, dynamic systems with attributes of primordial multicellular organisms and multifaceted ecosystems. The presence of biofilms may have a negative impact on the performance of various systems, but they can also be used beneficially for the treatment of water ...


    By IWA Publishing

  • Urine nitrification and sewer discharge to realize in-sewer denitrification to simplify sewage treatment in Hong Kong

    The chemically enhanced primary treatment works in Hong Kong will be upgraded for biological nitrogen removal. This study proposed a novel approach to waive the upgrading by urine source-separation, onsite nitrification and discharge of nitrified urine into sewers to achieve in-sewer denitrification. Human urine was collected and a lab-scale experiment for full urine nitrification was conducted. ...


    By IWA Publishing

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