Hydrodynamic simulations and biological modelling of an Anammox reactor

BACKGROUND: The design of anammox process reactors should be addressed to obtain maximum sludge retention and maximum removal efficiency, and also prevent the inhibition of microorganisms. The conventional biological models (activated sludge models, ASM) are only focused to test the influence of operational parameters on the biological performance. This study integrated computational fluid dynamics (CFD) and biological modelling (ASM) for the description of a novel anammox reactor configuration. RESULTS: A full description of the hydrodynamics, the mixing degree of the system and biological performance within the overall reactor domain was obtained. The strong recirculation of the system and the internal plates favoured correct mixing of the overall system, despite a particular point having a preferred flow in the inlet stream of the reactor. From the removal rates distributions calculated with the model, it was feasible to demonstrate that 45% of the domain had a zero reaction order with respect to the ammonium substrate (nitrite was in excess). CONCLUSIONS: Model integration was demonstrated to be a powerful tool for the design of an anammox reactor. It was useful to obtain information about the overall mixing in the system, determine death zones of flow, and points of maximum and minimum removal efficiency. (C) 2017 Society of Chemical Industry