Modelling of periodically operated, continuous activated sludge process for comparative simulation of on-off control algorithms

The mathematical model of a periodically operated continuous activated sludge process was developed to simulate the dynamic performance of this process during the aerobic and the anoxic periods, as well as to simulate the control sequences. An appropriate control strategy (for each process individually) can be chosen by real-world experiments, but even for pilot plants these experiments are very expensive. Hence, more inexpensive simulation experiments are very attractive. Simulation results, based on a verified mathematical model for the pilot plant, show that it is possible to find by simulation studies the appropriate rule-based, on-off control algorithms to ensure that all the controlled variables (organic substrate concentration, ammonia nitrogen concentration and nitrate plus nitrite concentration) have values which are less than the maximum admissible values.