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A Model To Predict Long-Term Performance of Vapor-Phase Bioreactors: A Cellular Automaton Approach
journal contribution
posted on 2002-05-01, 00:00 authored by JiHyeon Song, Kerry A. KinneyA novel numerical model was constructed to predict
performance of vapor-phase bioreactors (VPBs) operated
over extended periods. This model incorporates two
unique features to simulate changes in pollutant removal
efficiency and biomass accumulation: (1) total biomass is
divided into two microbial components, active and
inactive biomass, and (2) biomass growth and biofilm
thickness changes are simulated by means of a cellular
automaton (CA) approach. The CA approach, a differential-discrete algorithm, numerically allows the excess quantity
of biomass in each numerical element to move toward
the biofilm surface as biomass accumulates. One set of
experimental bioreactor data was used to estimate unknown
model parameters. A 90-day simulation using the estimated
parameters agreed with pollutant removal and biomass
accumulation profiles determined experimentally. Four
additional model simulations using the same estimated
model parameters were generally consistent with
experimental data collected from a series of toluene-degrading VPBs operated over a range of conditions. Model
predictions imply that the decline in bioreactor performance
observed over extended operation was caused by a
decline in the active biomass fraction and a decrease in
the biofilm specific surface area. This CA model provides
insight into biomass accumulation during complex
bioreactor operation and improves our capability to
predict long-term VPB performance.