Simplified models for packed‐bed biofilm reactors

Skowlund, Christopher T.; Kirmse, Dale William

doi:10.1002/bit.260330205

Cited by 14 publications

(4 citation statements)

References 14 publications

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“…Based on these studies, differences in substrate utilization kinetics of free and attached bacteria seem to be system and organism dependent. Although mathematical models to evaluate steady-state biofilm kinetics have been documented (Harremoës, 1978;LaMotta, 1976;Rittmann and McCarty, 1980;Skowlund, 1990;Skowlund and Kirmse, 1989), very few studies on biofilm-mediated degradation kinetics of VOCs exist. Arcangeli and Arvin (1992) studied the biodegradation of toluene (sole carbon and energy source) by biofilm cells.…”

Section: Introductionmentioning

confidence: 99%

Toluene degradation kinetics for planktonic and biofilm‐grown cells of Pseudomonas putida 54G

Mirpuri

Jones

Bryers

1997

Biotechnol. Bioeng.

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Toluene degradation kinetics by biofilm and planktonic cells of Pseudomonas putida 54G were compared in this study. Batch degradation of 14 C toluene was used to evaluate kinetic parameters for planktonic cells. The kinetic parameters determined for toluene degradation were: specific growth rate, µ max = 10.08 ± 1.2/day; half-saturation constant, K S = 3.98 ± 1.28 mg/L; substrate inhibition constant, K I = 42.78 ± 3.87 mg/L. Biofilm cells, grown on ceramic rings in vapor phase bioreactors, were removed and suspended in batch cultures to calculate 14 C toluene degradation rates. Specific activities measured for planktonic and biofilm cells were similar based on toluene degrading cells and total biomass. Long-term toluene exposure reduced specific activities that were based on total biomass for both biofilm and planktonic cells. These results suggest that long-term toluene exposure caused a large portion of the biomass to become inactive, even though the biofilm was not substrate limited. Conversely, specific activities based on numbers of toluene-culturable cells were comparable for both biofilm and planktonically grown cultures. Planktonic cell kinetics are often used in bioreactor models to model substrate degradation and growth of bacteria in biofilms, a procedure we found to be appropriate for this organism. For superior bioreactor design, however, changes in cellular activity that occur during biofilm development should be investigated under conditions relevant to reactor operation before predictive models for bioreactor systems are developed.

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Section: Introductionmentioning

confidence: 99%

Toluene degradation kinetics for planktonic and biofilm‐grown cells of Pseudomonas putida 54G

Mirpuri

Jones

Bryers

1997

Biotechnol. Bioeng.

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“…The Monod kinetic term, S/K S + S, represents the substrate limitation of a single substrate, S. Mass transfer limitations inside the biofilm result in decreasing microbial activity with increasing biofilm depth (Grasmick et al, 1979). It has been reported that the active biofilm length is on the order of 100 m (Harris and Hansford, 1976;Skowlund and Kirmse, 1989). The last term, B/K B + B, represents these diffusional limitations on the biomass growth and was used instead of complex calculation of an effectiveness factor.…”

Section: Model Equationsmentioning

confidence: 99%

An optimal operating strategy for fixed-bed bioreactors used in wastewater treatment

Benthack

Srinivasan

Bonvin

2000

Biotechnol. Bioeng.

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Optimization of a fixed-bed bioreactor used in wastewater treatment is addressed. The objective of the optimization is to maximize the treatment efficiency of the biofilter by manipulating the feed flowrate whilst satisfying operational constraints. Numerical results indicate that the optimal input is characterized as being on the boundary of the admissible region. Thus, the characterized optimal solution is implemented using a simple feedback control law, which provids the optimal input profile despite variations in substrate inlet concentration and biomass growth rate.

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“…Numerical continuation methods6 were used to vary the parameters a, p, and y so as to match the numerical solution to the experimental biomass data. Because the experimental data gives a volume average biomass density for each of the inner, middle, and outer portions of the pellet, continuous biomass density functions determined from the solutions to (15) through (19) were also volume averaged.…”

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confidence: 99%

Diffusion and reaction within porous packing media: A phenomenological model

Jones¹,

Dockery²,

Vogel³

et al. 1993

Biotech & Bioengineering

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A phenomenological model has been developed to describe biomass distribution and substrate depletion in porous diatomaceous earth (DE) pellets colonized by Pseudomonas aeruginosa. The essential features of the model are diffusion, attachment and detachment to/from pore walls of the biomass, diffusion of substrate within the pellet, and external mass transfer of both substrate and biomass in the bulk fluid of a packed bed containing the pellets. A bench-scale reactor filled with DE pellets was inoculated with P. aeruginosa and operated in plug flow without recycle using a feed containing glucose as the limiting nutrient. Steady-state effluent glucose concentrations were measured at various residence times, and biomass distribution within the pellet was measured at the lowest residence time. In the model, microorganism/substrate kinetics and mass transfer characteristics were predicted from the literature. Only the attachment and detachment parameters were treated as unknowns, and were determined by fitting biomass distribution data within the pellets to the mathematical model. The rate-limiting step in substrate conversion was determined to be internal mass transfer resistance; external mass transfer resistance and microbial kinetic limitations were found to be nearly negligible. Only the outer 5% of the pellets contributed to substrate conversion.

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Simplified models for packed‐bed biofilm reactors

Cited by 14 publications

References 14 publications

Toluene degradation kinetics for planktonic and biofilm‐grown cells of Pseudomonas putida 54G

Toluene degradation kinetics for planktonic and biofilm‐grown cells of Pseudomonas putida 54G

An optimal operating strategy for fixed-bed bioreactors used in wastewater treatment

Diffusion and reaction within porous packing media: A phenomenological model

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