Implement kinetic models
Program the Monod and Haldane kinetic expressions for phenol biodegradation and biomass growth in AquaSim.
Education / B.Eng. Research
B.Eng. Research Project · 2010–2014
Biofilm Modelling in a Continuous Stirred-Tank Bioreactor
Engineering project focused on the numerical modelling of phenol biodegradation, biomass growth and biofilm development using the AquaSim simulation environment.
The Engineering Project
Numerical analysis of phenol biodegradation in well-mixed CSTR with biofilm formation.
The project examined phenol biodegradation by Pseudomonas putida using two single-substrate kinetic models and two reactor configurations implemented in AquaSim.
The Monod model and the Haldane model were programmed for a continuous stirred-tank bioreactor with complete mixing and for a biofilm reactor. The Haldane model additionally accounted for substrate inhibition.
Simulation studies were used to examine the influence of mean residence time, initial phenol concentration and gas hold-up on the time required to reach steady state. For the biofilm reactor, biofilm-thickness growth and the substrate-concentration profile across the biofilm were also analysed.
The selected operating conditions were subsequently used to compare three literature-based sets of kinetic parameters corresponding to different Pseudomonas putida strains.
Project Objectives
Comparing kinetics, reactor configurations and process conditions.
Compare reactor configurations
Represent both a completely mixed continuous reactor and a reactor containing a growing biofilm.
Study process parameters
Analyse the influence of residence time, initial phenol concentration and gas hold-up on reactor behaviour.
Evaluate biofilm development
Simulate biofilm-thickness growth and examine how substrate concentration changes across the biofilm.
Project Workflow
From kinetic equations to reactor-behaviour analysis.
01
Literature kinetic data
→
02
Monod and Haldane model definition
→
03
AquaSim implementation
→
04
Process-parameter studies
→
05
Steady-state and biofilm analysis
Methods
Tools and engineering methods
Project Scope
Work completed during the project
- Formulation of process variables, mass balances and kinetic expressions for substrate degradation and biomass growth.
- Implementation of Monod and Haldane kinetic models in AquaSim.
- Configuration of a completely mixed continuous reactor and a biofilm reactor.
- Simulation of phenol concentration and biomass concentration as functions of time.
- Investigation of mean residence time, initial phenol concentration and gas hold-up.
- Simulation of biofilm-thickness growth and substrate profiles across the biofilm.
- Comparison of three literature-based kinetic parameter sets for different Pseudomonas putida strains.
- Interpretation of differences between the Monod and Haldane models, including the effect of substrate inhibition.
Simulation Findings
Main observations from the numerical study.
Kinetic-model differences
The Monod model predicted faster degradation at increasing substrate concentration, while the Haldane model reproduced the inhibiting effect of high phenol concentration.
Influence of residence time
Increasing mean residence time generally reduced the time required to reach steady state, with 60 hours selected for the subsequent comparative simulations.
Strain comparison
Among the three literature-based parameter sets, Pseudomonas putida Q5 produced the most favourable simulation results in both kinetic models.
Biofilm-thickness effect
Biofilm growth increased process intensity only up to a limiting thickness. Beyond that range, phenol degradation decreased rapidly.
Engineering Thesis
Analysis of Biofilm Properties in a Continuous Stirred-Tank Reactor Using AquaSim
The thesis combined biochemical reaction kinetics, reactor mass balances and numerical simulation to compare suspended-growth and biofilm-based phenol biodegradation systems.
It was my first academic project centred on mathematical process models and simulation-based interpretation of reactor behaviour.