de - Beste verfügbare Techniken (BVT) - Umweltbundesamt

Chapter 2
Stack gas scrubbing, with hypochlorite or by using carbon adsorption or biological filters may
be necessary for fermenter emissions that are malodorous. In these techniques the use of
chemical scrubbers will require the blowdown of unused chemicals, which will require
treatment before disposal. These systems typically have high maintenance costs. Carbon
adsorption is suitable for low contaminant loads only in order to ensure acceptable carbon life,
and also the high humidity of the fermenter exhaust, particularly during the sterilisation cycle
can interfere with the adsorption process on the carbon. Carbon adsorbers are mechanically
simple and can achieve a consistently high performance for odour removal. Biofilters are simple
with relatively low capital costs, but hot fermenter exhaust arising during the sterilisation cycle
will require cooling to between 25 and 35 °C.
Equipment used for crystallisation, filtration, drying and blending is vented via a chilled water
scrubber to the air, with the solvent removed from the scrubber liquor by distillation. Used
solvents can be recovered and re-used.
H2O Waste gas
Re-use
VOC
Solvent
Exhaust gas
Biomass and auxiliaries
Broth and auxiliaries
Scrubber
Solvent recovery
Sterilisation filter
Hazardous ?
Inactivation
Biological treatment
Waste water
Figure 2.33: Applied abatement techniques for the waste streams from fermentation
Disposal
OFC_BREF Dezember 2005 71