Online-simulation of the WWTP to minimise the total emission of WWTP and sewer system.

In this paper, the application of a WWTP-Online-Simulation with the objective to reduce the total emission into the receiving waters is explained. Apart from an introduction and a short description of the possible reduction potentials, first results of the current research project (financed by the German ministry BMBF) are presented. Results of the pilot plant with different experiments of increased stormwater inflow than usual and different control strategies showed the possibility to treat stormwater up to the quadruple dry-weather flow while still meeting the effluent values. However, this is not always guaranteed, and thus a monitoring system with integrated control strategies which is adapted to the load case "stormwater" with prognosis load cases becomes necessary. In the presented example, the simulation (Activated Sludge Model 2d) achieved an excellent match with the measured effluent values of the aeration tank (NH4-N, NO3-N) over a period of several months. The most important prerequisites for good (online-) simulation results are the exact knowledge of the plant and the plausibility and alternative concepts for the measured values in case of sensor failure.