Modelling the Competition of Planktonic and Sessile Aerobic Heterotrophs for Complementary Nutrients in Biofilm Reactor


A comprehensive, simplified microbial biofilm model was developed to evaluate the impact of bioreactor operating parameters on changes in microbial population abundance. Biofilm simulations were conducted using three special cases: fully penetrated, internal mass transfer resistance and external mass transfer resistance. The results of model simulations showed that for certain operating conditions, competition for growth limiting nutrients generated oscillations in the abundance of planktonic and sessile microbial populations. These oscillations resulted in the violation of the competitive exclusion principle where the number of microbial populations was greater than the number of growth limiting nutrients. However, the operating conditions which impacted microbial community diversity were different for the three special cases. Comparing the results of model simulations for dispersed-growth, biofilms and bioflocs showed that oscillations and microbial community diversity were a function of competition as well as other key features of the ecosystem. The significance of the current study is that it is the first to examine competition as a mechanism for controlling microbial community diversity in biofilm reactors.


Civil, Architectural and Environmental Engineering

Keywords and Phrases

Biofilms; Computer simulation; Marine biology; Microbiology; Nutrients; Aerobic heterotroph; Biofilm reactor; Complementary nutrients; Microbial biofilm; Planktonic microbial populations; Sessile microbial populations; Bioreactors; abundance; biofilm; bioreactor; competition (ecology); growth; heterotrophy; mass transfer; microbial community; modeling; plankton; population ecology; sessile species; species diversity; conference paper; ecosystem; heterotroph; interspecific competition; mathematical model; microbial diversity; microbial growth; microbial population dynamics; microflora; nonhuman; nutrient limitation; oscillation; process model; waste water management; Bacteria; Models; Biological; Time Factors; Competition; Model; Oscillations

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International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

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© 2007 IWA Publishing, All rights reserved.

Publication Date

01 Apr 2007