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 investigate the performance and the operating characteristics of the plant concept developed for the extension of the main Vienna STP and to develop a simulation 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 comprising of four aeration tanks and a clarifier tank. The pilot plant layout allows three different operational modes, each of which has been operated for several periods. The performance of the pilot plant during these periods is described and the different operational modes are compared to each other.