Kinetics
The conversions within a cycle were investigated in cycle measurements.
The measurements were conducted once the system reached a steady
functional performance in terms of product spectrum and substrate uptake
rates. An overview of all cycle measurements performed is shown in
figure 4.
In all systems the majority of the conversions happened in a short
period when glucose was present. A process model was made to investigate
the stoichiometric and the kinetic characteristics of the conversions
observed as described in the material and methods section. An overview
of the obtained kinetic parameters and final product spectrum is given
in table 2.
The amount of stored polymer produced was estimated using the model. The
quantity varied per enrichment but was always significant. At an SRT of
50 d 0.47 gCOD storage polymer was estimated to be produced per gCOD
glucose consumed. This amount of storage polymer lowered to 0.43 and
0.32 gCOD·COD-1 respectively at an SRT of 10-20 d and
1-2 d. The maximum specific substrate uptake rate
(qSmax) decreased from 0.7
gCOD·gVSS-1·h-1 at 1-2 d SRT to 0.2
gCOD·gVSS-1·h-1 at an SRT of 50 d.