Figure 2.6 Protozoa in activated
sludge from a wastewater treatment
reactor: a) Vorticella microstoma, b)
Euplotes, c) Glaucoma, d) Prorodon.
BIOREACTOR IMAGING
Bioreactors are essentially multiphase systems in which the mass (and in some processes
the heat) transfer is a key issue. The characterisation of mixing has received therefore a
lot of attention. Traditionally residence time distributions obtained by inert tracer
injection have been used for liquid, gas, and more seldom solid phases (Tatterson, 1991;
Lumley and Horkeby, 1989).
Imaging methods have been developed, which provide two types of information:
- The global characterisation of the mixing, where the 2D or 3D distribution of at least
one of the components of the multiphase system is given: the changes of a physical
property with respect to the component concentration are monitored. - The characterisation of flow patterns and velocity fields by tracking the motion of
individual particles
Multiphase bioreactor design 38