Upgrading of wastewater treatment plants equipped with rotating biologicalcontactors to nitrification and P removal

In the course of a research project on the further use of treatment plants with rotating biological contactors for nitrification and phosphorus remova l, full-scale investigations were carried out. From the results design para meters for phosphorus pre-precipitation as well as for secondary and tertia ry nitrifying RBCs were derived. Regarding the impact of the oxygen concent ration, the alkalinity and the pH, respectively, on nitrifying biofilms, fo rmer research work could mostly be confirmed. Concepts for the upgrading of different types of RBC plants are discussed - including cost estimations.