Determination of the oxygen profile in a nitrifying Moving Bed Biofilm Reactor by microelectrodes and a mathematical model

In this paper we determine the oxygen profile in a biofilm on suspended carriers in two ways: firstly by microelectrode measurements and secondly by a simple mathematical model. The Moving Bed Biofilm Reactor is well-established for wastewater treatment where bacteria grow as a biofilm on the protective surfaces of suspended carriers. The flat shaped BiofilmChipTM P was developed to allow good conditions for transport of substrates into the biofilm. Firstly, the oxygen profile was measured in situ the nitrifying biofilm with a microelectrode and secondly, the profile was simulated with a one-dimensional mathematical model. We refined a classical model by adding a dynamical tank equation, to connect the tank to the biofilm through the boundary conditions. This proved to be an important key in achieving relevant simulations. We also estimated the erosion parameter λ to increase the concordance between the measured and simulated profiles. Promising results have been obtained from our mathematical model. The accordance improved when simulating profiles without the boundary layer. Microelectrode measurements are a valuable tool in design of new suspended carriers