The Biological Degradation

At the same time, depending on the origin, type and quantity of the contaminants, and process conditions, substantial differences in regard to the speed of the degradation and the elimination performances can be observed.

Whereas the treatment of similar substrates containing contaminants (alcohols, sugar, etc.) proceeds relatively quickly and smoothly in terms of quantity, the biological treatment of complex, poorly degradable (also referred to as “persistent”) substrates (larger, substituted molecules, salinity, fluctuating composition) is often problematic, because the persistence of a chemical substance does not only depend upon its structure, but to a large degree, on environmental factors such as

• pH-value,
• Temperature,
• Salinity,
• Electro-chemical potential,
• Availability and concentration of the substance,
• Presence of additional substrates and
• Presence of degradable-relevant microorganisms

Xenobiotica*-degrading activities occur widely in the microbial world – under the right conditions.

Even with adapted organisms, a stable biodegradation of xenobiotica over a longer period of time can be guaranteed in continually operating systems under special, optimum conditions.
A further advancement in biological systems for the biodegradation of xenobiotica is achieved through the “design” of active, mixed cultures (biomass) specially tailored for the specific situation.

This method is based on the cultivation and guaranteed, continual availability of cultures specially adapted to contaminants in the microbial flocculent sludge, or the bioreactor.

This relatively new method encompasses the preparation, manufacture and application of active, specialised “starter cultures” for addressing specific environmental problems.

* Xenobiotica (poorly degradable substances) are synthetically manufactured chemical substances which lend the chemical structure of substances and their substitutes a resistance to biodegradation, or persistence vis á vis nature.