Figure 6 The simulated steady-state amount of dinitrogen gas dissolved in the effluent as functions of dissolved oxygen according to simulations made by Van Hulle (2005). The simulation to the left was done under the assumption that the process was fed by a substrate containing 100 mg NH +4 - N l −1 while the right simulation assumed a substrate containing 200 mg NH +4 - N l −1. The optimal DO level is dependent on all the factors that affects the transport rate of oxygen into the nitrifying layer, such as the thickness of the biofilm’s boundary layer and temperature in the reactor (Hao, J. J Heijnen, and van Loosdrecht 2002). It is also affected by the ammonium load on the process. Figure 7A-C illustrates how the optimal DO level varies as a functions of different process parameters.
Published on Nov 9, 2011