Document Type


Date of Award


Degree Name

Master of Science in Chemical Engineering - (M.S.)


Chemical Engineering, Chemistry and Environmental Science

First Advisor

Basil Baltzis

Second Advisor

Dana E. Knox

Third Advisor

Piero M. Armenante


The dynamics of pure, strong, double competition between two microbial populations in an ideal chemostat have been investigated by using mathematical and numerical analysis. The two nutrients competed for have been assumed to be complementary for both competitors. Inter active models have been used for the specific growth rates. Two cases have been considered; one in which neither of the two substrates exerts inhibitory effects on the growth of either one of the competing populations, and one in which the growth of one population is inhibited by only one of the two substrates. The primary focus of this investigation was on the coexistence steady state and the ability to maintain a mixed culture in a chemostat. It has been found that except for rare cases, there are regimes in the operating parameters space of a chemostat where coexistence is possible. Conditions for stability have been derived, situations where multiple states are possible have been found, and the main results are presented in the form of characteristic two-dimensional diagrams.