Systems Engineering for Water and Wastewater


© Fraunhofer IKTS
Stirred tank reactor with readjusted submersible mixers.
Floating deposits (lab scale test and tomogram).

When handling opaque, fibrous substances in particular (i.e. digestate) there are almost no options in terms of experimentally evaluation current mixing quality in the system. Thus efficiency of a working biogas plant can hardly be determined. Along with dead spots floating or sinking deposits hinder the optimal production of biogas.

To cope with these problems tools like process tomography, numeric flow simulation and specialized measurement technology for gathering granulometric and rheological characteristics are used by the working group “Mixing Processes and Reactor Optimization”.

By that means a visualization and quantification of mixing processes with highly concentrated, non-Newtonian multiphase material systems as basis for further process optimization becomes possible. With the help of specialized scaling criteria these tools allow the selection of eligible mixing technologies and reactor design. Furthermore these analyses help qualifying existing models for numerical flow simulation of multiphase material systems.

The Fraunhofer IKTS has been rewarded with the German Agriculture Innovation Award at the 5. Biogas Innovation Congress in May 2012 for the recent studies regarding improvement of mixing processes in biogas plants.




  • Procedural and energetic validation of mixing processes in lab- and pilotscale
  • Deduction and controling of methods for mixing optimization
  • Scaling of corresponding full scale process parameters
  • Comparison and development of various reactor and mixing systems
  • Assassment of multiphase processes

Current research

Smart pump systems for mixing of biogas reactors

Current research

Efficient and wear-resistant stirrers for biogas plants