A new approach towards modelling of the carbon degradation cycle at two-stage activated sludge plants.

A pilot plant has been operated in order to investigate the performance and operating characteristics of the plant concept developed for the extension of the main Vienna STP. Due to the different operational modes included in the plant concept, modelling of the carbon degradation becomes of crucial importance. A new activated sludge model is introduced which combines parts of the carbon degradation model concepts as they have been released in the ASM1-model and the ASM3-model, respectively. A method is presented which utilises results from mass balance calculations and sludge stabilisation experiments to reduce the uncertainty in the determination of the values of the simulation model parameters.