Modyfikacja obecnej postaci modelu osadu czynnego ASM 2d

Pilot-scale investigations into nitrogen and phosphorus removal by the activated sludge process were carried out in the wastewater plant of Poznań. Under laboratory conditions, the following parameters were examined: Ammonia Utilization Rate (AUR), Nitrate Utilization Rate (NUR), Phosphorus Release Rate (PRR) and Phosphorus Uptake Rate (PUR) for the activated sludge coming from a pilot plant. With the results obtained it was possible to calibrate and verify the mathematical model describing the ASM 2d activated sludge for the pilot plant of interest. It was found that the predictions of phosphorus variations established in terms of the original ASM 2d model were inadequate when the untreated wastewater contained very high amounts of Volatile Fathy Acids (VFA). Despite the presence of VFA in the anoxic or oxic phase, phosphorus release terminated, followed by the initiation of phosphorus uptake, thus resulting in a rapid decrease of phosphates concentration in the solution. Under such conditions the ASM 2d model predicts further release of phosphates up to a complete VFA exhaustion. The proposed modification of the model includes the incorporation of two terms, Ko/(Ko+So) and Kno/(Kno+Sno), into the equation for the PHA storage rate, which results in the blocking of the process under oxic and anoxic conditions, respectively. With such modification it is possible to make the predictions of the model far more adequate to reality. In the study, consideration was also given to the problem of model calibration with respect to the denitrification effect.