de - Beste verfügbare Techniken (BVT) - Umweltbundesamt

Chapter 2
Further steps can also be carried out in order to optimise the purity or concentration. The choice
of methods are:
• evaporation
• ultrafiltration
• chromatography and/or ion-exchange
• reverse osmosis.
After purification, the product is obtained by conventional crystallisation and drying.
2.6.2 Environmental issues
Table 2.18 gives example data for waste streams from fermentations, for examples for waste
waters streams from fermentations see Section 4.3.2.11. Figure 2.33 shows the applied
abatement techniques. The main waste streams from fermentation processes are:
• biomass, possibly containing active pharmaceutical ingredients and possibly filtration
auxiliaries
• filtered broth, possibly containing active pharmaceutical ingredients and precipitation
auxiliaries
• exhaust gas from seed and fermentation stages, containing broth aerosol, possibly being
malodorous
• VOC from solvent use
• large volumes of waste water streams.
If the biomass is classified as hazardous, it must be treated to reduce its activity to a level lower
than 99.99 %. Inactivation is carried out, for example, by treatment with heat, with chemicals or
by application of vacuum evaporators at temperatures of 85 to 90 °C. Alternatively, the
hazardous biomass is incinerated, in which case the combustion device must be operated at
temperatures above 1100 ºC and dwell times of at least two seconds in order to achieve
acceptable destruction efficiency. If the biomass is classified as non-hazardous, deactivation is
generally not required, unless demanded by national regulations.
The filtered broth is usually treated in a biological WWTP.
Exhaust gases from the seed and fermentation stages contain between 1.5 and 2.5 % v/v carbon
dioxide and – where no filters are used – traces of broth in an aerosol form. Often an in-vessel
detector is used to automatically close the exhaust valve or to control the addition of an
antifoaming agent if there is a risk of the broth splashing or foaming the outlet. Each fermenter
exhaust may be backed-up by a downstream cyclone. Where appropriate, thermal oxidation is
applied.
Waste stream Properties
[15, Köppke, 2000]
Exhaust gas 0.5 to 1 m 3 per m 3 liquid phase and per minute
Table 2.18: Example data for the waste streams from fermentation
70 Dezember 2005 OFC_BREF