Urban Waste Water

The usage of the sedimentation effect of the buffer tanc in DIC-SBR-plants

Simulation calculations have been used to develop a standardised method for the calibration and validation of the DIC-SBR process. These calculations have formed the basis of targeted analyses for the further reduction of discharge values and operating costs. 



In the DIC-SBR process (Differential Internal Cycle strategy – Sequential Batch Reactor process), a buffer tank which acts as a receiver, hydrolysis and compensating tank, or to some degree as a preliminary sedimentation tank, is arranged upstream of the SB reactors in which the biological treatment of sewage is completed.  Two separate waste water streams are fed from this buffer tank to the SB reactors on a cyclical basis.  This process is associated with low COD and nitrogen discharge values, and ensures the effective biological elimination of phosphate.

The object of this project was the use of simulation calculations generated by the SIMBA program to evaluate new operating strategies for the DIC-SBR process, with a view to optimising the evaluation process or commercial operating methods.


  • A standardised method for the calibration and validation of SBR installations has been developed, based upon the characteristic evaluation of sewage.
  • Investigations conducted using model sewage treatment plants have shown that, depending upon the waste water from the sewage treatment plant concerned, the sedimentation effect in the buffer tank can be exploited to achieve further reductions in discharge values and the further optimisation of operation.  Analyses for the optimisation of plant management have resulted in a 50% reduction in discharge values, a saving in operating costs associated with a 14% reduction in aeration times and further operating cost savings associated with the reduced production of surplus sludge (by approximately 10%).

Project Participants

Implementing Institution

LimnoTec Abwasseranlagen GmbH

Cooperation partner

Ingenieurbüro Fröse und Olderdissen

Abwasserzweckverband Hettstedt, Prossen und Polenz

Kläranlagen der Städte Bad Zwischenahn und Rödinghausen

More Project Informations

Project title:  The usage of the sedimentation effect of the buffer tanc in DIC-SBR-plants

Project number:  02WA0140

Project period:  2001 - 2003

Project region:  Germany (North Rhine-Westphalia)

Project contact:

Herr Dr. Holm

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Source: German National Library of Science and Technology Hannover (TIB)