Comparison of different operational modes of a two-stage activated sludge pilot plant for the extension of the Vienna STP

A pilot plant has been operated over a period of two years in order to inve stigate the performance and the operating characteristics of the plant conc ept developed for the extension of the main Vienna STP and to develop a sim ulation model which will be applied for operation support of the full stage plant. The pilot plant is a two stage activated sludge plant, each stage c omprising of four aeration tanks and a clarifier tank. The pilot plant layo ut allows three different operational modes, each of which has been operate d for several periods. The performance of the pilot plant during these peri ods is described and the different operational modes are compared to each o ther.