Investigation of substrate concentration effects on kinetic parameter changes in activated sludge plants

In this study, kinetic parameter changes in a laboratory model activated sludge plant were investigated using Biochemical Oxygen Demand (BOD) values obtained from dilution and respirometric methods and Chemical Oxygen Demand (COD) values.In the experiments, four different tests having similar initial conditions were performed and multiple tests were tried for the calculation of kinetic parameters. Kinetic parameters were calculated using Mixed Liquor Suspended Solid (MLSS) and Mixed Liquor Volatile Suspended Solid (MLVSS) as microorganism concentration. Substrate removal efficiencies varied in the range of 46,88 - 73,36 %. Maximum removal efficiency was 69,23% for the dilution method BOD values. Kinetic parameters were determined in hypervariable distribution for all experience. The best results of which kinetic coefficients are suitable were obtained from the respirometric BOD measurements. There is % 98,6 correlation between the obtained values using BOD and COD measurements. There is % 97,8 correlation between dilution and respirometric values for the mean of BOD. MLVSS values gave better results than MLSS values for the calculation of kinetic coefficients. Kinetic coefficients obtained having higher substrate concentration are more variable than other experience and were outside typical ranges.