Undesirable operation of continuous bioreactors in the form of
washout, multiple steady states oscillations, limit cycles, etc. arise
when microbial kinetics are modified to accommodate substrate
and/or product inhibition [1–3], or through uncommon control
strategies [4–6]. In bioremediation processes, substrate inhibition
is a common feature, and in such cases the dynamic behaviour of
CSTRs has been analyzed via dynamic simulations [7], via bifurcation
analysis [8], and via analysis of forced waveform feeding [9].
The impact of substrate inhibition on some conventional wastewater
treatment processes such as organic substrate removal [10] and
nitrification processes [11] has also been explored. In some cases‘‘operability’’, which refers to the identification of regions
providing stable CSTR operation, have also been documented,
which provides practitioners with valuable guidance on operating
conditions that result in stable process performance.