Microbial kinetics yield coefficient

Two continuous stirred-tank fermenters are arranged in series such that the effluent of one forms the feed stream of the other. The first fermenter has a working volume of 100 1 and the other has a working volume of 50 1. The volumetric flowrate through the fermenters is 18 h-1 and the substrate concentration in the fresh feed is 5 g/1. If the microbial growth follows Monod kinetics with //, = 0.25 h-1, Ks = 0.12 g/1, and the yield coefficient is 0.42, calculate the substrate and biomass concentrations in the effluent from the second vessel. What would happen if the flow were from the 50 1 fermenter to the 100 1 fermenter ... 

Parametric uncertainty A great number of bacterial species carry out the transformations of organic load and nutrients in wastewater treatment processes without direct or easily comprehensible relationships between the microbial populations and viability. The role of each bacterial species is fuzzy [30], and aspects such as cellular physiology and its modeling are not easily understood from external measurements [18], [68]. As a first consequence, the kinetics of these transformations is often poorly or inadequately known [66]. Extensive efforts to model the kinetics have been undertaken, but these have not been successful to elucidate how yield coefficients, kinetic parameters and the bacterial population distribution change as a function of both, the influent composition and the operating conditions. 

The domination of microbial growth kinetics by the Monod equation has led to the development of techniques to determine the constants Ks and fim used in that equation. Whilst n is in fact dependent on other parameters, such as temperature and pH, in the usual case these are specified, and a design procedure requires values of the Monod constants under these conditions. The yield coefficient Y will also be required in order to link calculations of microbial growth to substrate concentrations. 

If the yield coefficient Y for the conversion of substrate into microbial cells is assumed to be constant, then when Monod kinetics are applicable the material... 

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