Biofilm Carrier

The carrier material EvU-Pearl® is a high performance filling material for industrial, municipal and further specialized applications, where it becomes necessary to use biofilm for wastewater treatment.

Today the use of these synthetic materials is known, among experts and customers, as moving-bed-technology. Multiple versions of filling/carrier material are being offered by now but often solely defined and compared by the specific growth area per m³.

But it requires more than that to use the advantages of biofilm technology . To inform yourself further, you can read more about filling material, biofilm and related technologies right here.

Interactive Presentation of EvU Pearl®


In national and international communities and businesses biological processes to treat wastewater are being successfully applied. Many of the technologies used today are combined processes in order to be more cost -effective and treat wastewater more efficiently. Particularly applications which allow for a biofilm to establish itself in a system of a wastewater treatment plant, have proven themselves over the last years. We therefore recommend our widely used filling material, biofilm carrier EvU Pearl® to every plant operator.


EvU Pearl® is an extrusion process manufactured, cylindrical, synthetic hollow body with an inner and outer microstructure. Because of the structure it has got a large specific surface. Stability is ensured by adequate wall thickness. You can order EvU Pearl® in different sizes, Dichtebereiche and colors . We will gladly customize your request.

Advantages EvU Pearl® aus:
  • Simple geometrical structure with large surface (=large potenial growth area )
  • Structure enables good flow and results in a stabil biofilm
  • Minor susceptibility to clogging due to hair/fiber with excellent durability
  • By adjusting the structure you can enhance aerobic(use of oxygen) or anoxic (without oxygen) processes
  • Broad spectrum of application
  • Strong price-performance ratio


To provide a growth area for biofilm within the bioreactor is the primary function of EvU Pearl®. In the process, the entire carrier surface will be overgrown by organism, depending on operating conditions, more on inner and less on outer structures. The entire overgrown area (biofilm area) is biological active and not only shielded areas, as often misstated. Many carriers have an inner microstructure with a large surface area which will be biofilm overgrown and will be only partially active. Those inner structures (ramifications) are not absolutly necessary. A simple carrier structure (for instance cylindrical) with an enlarged surface area is sufficient to provide just as much surface area while operating then materials with theoretical larger surfaces. Excess biomass has to be easily removeable from material and be resistible to clogging. An unsenitivity to unavoidable clogging due to hair and fibers has to be proven.

Further important aspects of carrier selection are:
  • Adjustability of required density affects operating qualities (fluidization energy, sinking, floating)
  • Durability of carrier material
  • Suitability for differnt retainer devices
  • Are there any application suggestions for your specific need with our carrier material?


The biofilm process is one of the oldest technologies to treat wastewater. It is a known fact that biofilm performs very effectively. In general it is defined as „a natural accumulation of microorganism, sorbed substances and retained solids on a surface“. Organisms adhered to an area will remain in one bioreactor. "Growth" on surfaces means going through differnt stages before a biofilm has formed completely. At the same time fibers make a seperation of biofilm to surrounding medium more difficult. Biofilm is not smooth and flat (in layers) but extends rather structured into the water.

A biofilm models are used for a more comprehensive understanding of interactions of influencing factors on the biofilm. They are, among other things, a requirement to design/ dimension biofilm reactors. The majority of models assume a two dimensional layered structure. Simplified the biofilm is divided into layers in which a variety of microorganism and organism settle. Those take on differnt tasks like degradation of pollutants in wastewater. With this segmentation one can for instance detect that aerobic microorganism will mostly colonize on regions close to surface and anaerobic microorganism on lower layers of biofilm.

Aerobic Systems

Movingbed Application of EvU Pearl®

Compressed air (fine-, medium- or coarse) gets carriers moving. Organisms which need oxygen can adhere to carrier material and remain within one system/tank.

In water- and wastewater treatment to degrade:
  • organic contaminations (carbon degradation)
  • anorganic pollutant particles (ammonium degradation by nitrification as a stage of denitrification process)

Anoxic/anaerobic Systems

Fluidized bed application for EvU Pearl®

The carriers are „being fluidized“ by rotating contactors -organism that don’t depend on disolved oxygen will settle here.

In water- and wastewater treatment to degrade:
  • organic contaminations (carbon degradation)
  • anorganic pollutant particles (denitrification process, Bio-P, acidification)

Other Opportunities

Application of EvU Pearl® as packing material

Carrier will be inserted in reactor/tanks/chambers/stages (packed or scattered) and not rotated or ventilated.

  • Example for coalescence separator:
    Material is integrated in separator and accumulates oil residues in wastewater.
  • Example for filter material in aquaristic or fish farming:
    The material is inserted prefabricated filter. Biofilm grows on material and treats water in cycle.

Successful Applications of EvU Pearl®:

Industry (clarification plants)

Libya, Spea –
hospital wastewater

Mexico, Byk Gulden –
pharmaceutical wastewater

Germany, Bronkow –
butcher shop wastewater

Germany, Siebenlehn –
leather industry

Germany, Drognitz –
camping ground

Municipalities (clarification plants)

Germany, Hohenroda –
reconstruction of biological contactor reactor - retrofitting to mbbr

Germany, Geroda –
mbbr as nitrification stage of pond

Poland, Kolo –
extension of clarification plant to 6000 m³/d

Germany, Velburg –
increasing biology efficiency