Background& Objective: Determination of microorganisms growth kinetic constant is one of the most important parameters for evaluation of municipal and industrial wastewater treatment plants efficiency. Monod Equation and activated sludge models (ASM1) are one of the most important relationships for design of activated sludge biological process.
Materials and Methods: Data obtained using a laboratory pilot in accordance with the amount of aeration, temperature and pH and the concentration of the feed inlet to the Ekbatan wastewater treatment plantin Tehran. Changes in microbial growth by measuring MLVSS and COD changes of input substrate in the range of 50-500 mg/L was investigated.
Results: The results of the ASM1 model for kinetic coefficients of Ks were determined as 31.2 gCOD.m-3, µH as 3.9 day-1, bH as 0.077 day-1 and YH as 0.51 gCOD XH (gCOD SS)-1. The difference between ASM1 and Common equations in activated sludge processes was 7.6%, 9.2%, 9.4% and 6.9% for Ks, µH, bH and YH, respectively.
Conclusion: Evaluation of Y, kd, k0 and Ks parameters in operation of Ekbatan wastewater treatment plant showed that ASM1 model could well determine the coefficients and therefore the conditions of biological treatment is appropriate.