Consequently, at fixed flow rates and dilution rates
under constant physical and chemical operating conditions,
i.e. under steady-state conditions, the specific
growth rate of the microorganism is dependent on the
operating dilution rate, up to a maximum value equal to
mmax (Fig. 2.5). If the dilution rate is increased above
mmax, complete wash-out of the cells occurs, as the cells
have insufficient time to ‘double’ before being washed
out of the reactor via the overflow. The point at which
this is just avoided is referred to as the critical dilution