This doctoral thesis focuses on combined mixing and aeration systems, which are primarily used in activated sludge tanks at wastewater treatment plants. These systems often differ in shape and installation from conventional aeration devices, such as diffusers or perforated grids.
Since combined systems are not currently a common choice in the design of activated sludge tank technologies, limited information is available regarding their operation and design. Relevant data are lacking in both normative documents and other technical literature, and even a clear definition of these systems is absent. These factors motivated a closer investigation of one of the two types of combined systems currently in use in the Czech Republic.
As part of the doctoral thesis, experimental measurements were carried out to examine three different sizes of one of the combined system types mentioned above. The measurements took place under real operating conditions, aiming to provide a more detailed characterization of the system. The most important parameter determined was the standard oxygen transfer rate.
The main objective of this thesis is to develop a conceptual approach for sizing combined systems. This approach is based on the results of experimental measurements, on the evaluation of treatment efficiency at several full-scale wastewater treatment plants where these systems are already in use, and on selected design relations commonly applied in wastewater engineering. The proposed method is subsequently applied to actual treatment facilities, thereby verifying its practical applicability.