Effect of biofilm growth on steady‐state biofilm models

Abstract

The results of numerical simulations for a growing biological film are presented to justify the use of steady-state biofilm models for approximating the behavior of both unlimited and shear-limited biofilms. For an unlimited biofilm we show that although the total biofilm thickness may continue to increase over time, the active biofilm volume will reach a constant value. We also show that the profile of active microorganisms within the biofilm will become constant with respect to the biofilm/fluid interface and simply move outward as the biofilm thickness increases. For a shear-limited biofilm we similarly show that once a "limiting" thickness has been reached the active biofilm volume, substrate consumption, and profile of active microorganisms within the biofilm will also be independent of the biofilm thickness.

Biomass accumulation and clogging in biotrickling filters for waste gas treatment. Evaluation of a dynamic model using dichloromethane as a model pollutant

“…Except for the start-up period, the development in G stat was linear. A pseudo steady-state biofilm performance, reflected in a linear increase in biofilm thickness or mass, accompanied with a constant EC is well documented in the literature and has been investigated theoretically and experimentally (LaMotta, 1976;Skowlund, 1990;Wanner and Gujer, 1986). A linear G stat accumulation for eight months was also observed by Zuber (1995) in a similar biotrickling filter system.…”

“…All other parameters used in these simulations are listed in Table I. As already discussed by Skowlund (1990), the assumption of a negligible formation of inerts (Y inert ‫ס‬ 0) does not lead to a proper description of the data (Alonso et al, 1997;Rittmann and Manem, 1992), because it predicts that the G stat eventually becomes constant with time. Another observation from this figure is that when mineralisation is neglected (no decay), the G stat accumulation predicted by the model is considerably higher than the one that was measured.…”

“…This type of model has been investigated intensively in biofilm research for waste water treatment systems, both theoretically and in laboratory set-ups (Horn and Hempel, 1997;Rittmann and Hanem, 1992;Wik and Breitholtz, 1996). The pseudo steady state that establishes itself after some time of operation was studied by Skowlund (1990). Gas-to-biofilm mass transfer is modelled using the approach of Diks and Ottengraf (1991).…”

Prediction of optimal biofilm thickness for membrane-attached biofilms growing in an extractive membrane bioreactor

“…Dynamic models which allow for biofilm growth have been used to describe and study different types of biofilm reactors (Benefield and Molz, 1985;Park et al, 1984;SBez and Rittmann, 1988;Skowlund, 1990;Wanner and Gujer, 1986). Often, investigators have neglected the influence of cell maintenance, cell decay, and/or cell detachment (biofilm attrition), factors which may prove useful in controlling biofilm thickness.…”

Remoção de sulfametazina em reatores anaeróbios tratando água residuária de suinocultura

“…Modelo Ajustado "(# $ ) = " + (" − " ) , 1980b;SKOWLUND, 1990). Baseando-se em um balanço energético entre a utilização de substrato e a energia requerida para a manutenção celular, esse modelo prevê que a massa de biofilme ativo em estado estacionário é proporcional à concentração de substrato disponível no meio líquido.…”