Document Type
Thesis
Date of Award
9-30-1987
Degree Name
Master of Science in Chemical Engineering - (M.S.)
Department
Chemical Engineering, Chemistry and Environmental Science
First Advisor
Basil Baltzis
Second Advisor
John E. McCormick
Third Advisor
Gordon Lewandowski
Abstract
It is known from the literature that out of any number of microbial populations competing purely and simply in an environment which is homogeneous and has time invariant inputs (e.g. in an ideal chemostat) only one population can survive in a steady state under any conditions. However it has been proven possible for two competitors to coexist in two interconnected chemostats, which indicates that spatial heterogeneities may lead to coexistence of pure and simple competitors. The present study investigates whether the spatial heterogeneities created by three interconnected bioreactors may lead to a mixed culture (i.e. coexistence) of three pure and simple competitors. It is shown that even if the characteristics of the competitors (i.e. their specific growth rates) are such that they allow each one of the competitors to grow faster than the other two populations under certain conditions, there are only discrete values of the design and operating parameters of a configuration of three interconnected chemostats that lead to coexistence of the three species. This result is of no practical importance since the ever existing fluctuations in the values of operating parameters (such as flowrates) can never allow operation at a specific set of values of the manipulated variables even with a perfect control device. Computer simulations though, indicate that there are conditions under which the dynamical response (transients) of the system is so slow that although one population will be eventually washed out, a mixed culture of the three competitors can be maintained (in an unsteady state) in the system for a considerable amount of time. The analysis also shows that the system never exhibits a sustained oscillatory response. The results are presented in two-dimensional projections of the operating diagrams.
Recommended Citation
Chang, Shiuan-Wu, "A theoretical investigation of the possibility of coexistence of three microbial populations competing purely and simply in configurations of three interconnected chemostats" (1987). Theses. 3057.
https://digitalcommons.njit.edu/theses/3057
