In this Master's Thesis the use of dynamic time warping in the eld of wastewater treatment is presented. Dynamic time warping is a method to compare data signals. It is used to assign the influent data points to the euent data point of a reactor. The assignment is performed by constructing a cost-matrix and then nding the optimal way diagonally through this matrix. An optimal con guration of the dynamic time warping algorithm was found and implemented in Matlab. It could been shown, that with dynamic time warping an approximation of the mean of the hydraulic residence time distribution could be determined. With larger hydraulic residence times the absolute error increases. The dynamic time warping analysis allow to dermine the hydraulic residence time for non-steady flow conditions. With generated data it could been shown, that it is possible to obtain Nash-Sutcliffe coeffcients above 0.6 in representing the variability of the hydraulic residence time with dynamic time warping for ideal reactor models with a number of reactors higher two and mean hydraulic residence times smaller two hours. It could further been shown, that normalizing the data signals improves the dynamic time warping results for rst order reactions with reaction constants between 0 and -0:1 1/hr. With in measurement campaigns on the wastewater treatment plant Kloten/Opfikon collected and generated data, dynamic time warping was used to identify the hydraulic residence time in sewer and grit chambers successfully. For mean hydraulic residence times smaller one hour the distribution of the discharge on reactors operated in parallel was approximated that the assumption of equal hydraulic residence times is no longer necessairy. For the wastewater treatment plant Kloten/Opfikon a relation of the ratio of the residence times in the parallel grit chambers and the measured discharge could been derived. The results were validated with a tracer experiment in the parallel girt chambers and the primary clari ers. Through the left grit chamber and primary clari er an approximately 10 % higher discharge was passing while the tracer experiment was running by a discharge of 765:3 81:9 m3/hr.