BIOFILM REACTORS CONFIGURATION FOR ADVANCED NUTRIENT REMOVAL

Characterization of a new biofilm reactors configuration was carried o ut on a pilot plant performing nitrification, pre- and post-denitrific ation. Thereby, degradation rate limitations whether there are related to mass transfer resistances, kinetic or stoichiometry - were determi ned for the different stages. The experimental results showed that und er certain conditions moderate aeration of the predenitrification stag e enhances both denitrification and organic carbon removal due to an a cceleration of diffusion rates. Post-denitrification was limited by th e addition of C-source exclusively, whereas nitrification was inhibite d by elevated organic loadings as well as low temperatures. The descri bed system offers a certain flexibility concerning BOD removal in the predenitrification stage because of the potentiality of aeration,as we ll as the possibility of recirculating nitrate very economically enabl ed by the small head losses in the systems. Furthermore, combination o f pre- and post-denitrification with biofilm systems leads to economic and safe processes for advanced elimination of nutrients such as nitr ogen and phosphorus.