Aerobes and Effluents - Environmental Biotechnology: Theory and Application - page 136

Figure6.5 ICIdeepshaftprocess
oxygen utilisation of around 90%, which is some 4.5 times better than conven-
tional activated sludge systems. The bubble contact time produced, averaging 90
seconds or more, is over six times longer than in standard diffused air systems.
It has a low footprint, making it ideal for use in restricted areas.
Pure Oxygen Systems
With process efficacy so closely dependent on aeration and the ability to support
a high microbial biomass, the use of pure oxygen to enhance the effective levels
of the gas dissolved in the effluent has an obvious appeal. The UNOX process,
which was developed by the Union Carbide Corporation is probably amongst the
best known of the pure oxygen activated sludge systems and Figure 6.6 shows
the general layout of the bioreactor vessels.
Pure oxygen obviously gives a better oxygen transfer rate per unit volume
of the bioreactor than can be achieved using conventional aeration methods.
In turn, this allows a heavier organic loading per unit volume to be treated