DEVELOPMENT OF A RECTION-KINETIC MODEL FO R OPTIMALIZING SINGLE BASINPLANTS WITH REDUCED SLUDGE

Peak loads in the form of freight, pH value and temperature are reliab ly compensated and biogenetically neutralized in reactors. The VLB rea ctor system with its high biomass content (1.5 - 5 g/l) is just as hig hly flexible and has just as large a buffer capacity as a conventional plant with increased sludge returns. In this way the speed of the nut rient consumption increases in just the same way as through higher tem perature and a higher capacity range is left for aerobe sludge stabili sation. Since, in the case of the VLB Type B1 and B2 reactors the bact eria discharge is strongly suppressed and almost prevented, plants are given with high performance densities. It has been observed that the smaller VLB reactors, Type B1 with their lower dwell times have a high er performance density when compared with the large long period reacto rs B1 and A2. The degree of efficiency of these smaller B1 reactors is , after all, approx. 50% instead of the theoretical 30% as was calcula ted on the basis of the shorter dwell time compared with that in the l arger reactors. Kinetic analysis of the measured results document a hi gher sludge age which likewise leads to lower biomass yields as does t he higher temperature. The paper to hand proves that these reduced bio mass yields are more or less strongly reduced depending on type of pla nt. Moreover, in the most effective type of plant, the 7-day compensat ion basin with biomass retention (Type B2) can reach on average of 0.2 5 kg TS(z)/kg BSB5red, or 0.12 TS(z)/kg CSB(red) or 0.48 kg TS(z)/kg C SB(red), compared with the normal figure of 0.90 kg TS(z)/kg BSB5red o r 0.48 kg TB(Z)/kg CSB(red), respectively. According to the new ATV Re gulations A 131, which first appeared after the work had been conclude d and are valid as the basis for dimensioning municipal clarification plants, a significantly lower biomass yield can be calculated for the conditions in the VLB plant.