Student practical training / Bachelor theses / Master theses / Diploma theses

In Germany, wastewater is treated in 10000 plants, which use 4,400 GWh of energy per year. From this big figure, only the aeration process in activated sludge basins consumes up to 50%. Aerators with flexible membranes are currently state of the art. However, the aeration process suffers from some limitations such as large bubble size, high-pressure drop of the diffusers, and inadequate mixing. Initial bubble size in gas dispersion is of great importance since it determines the ascent and coalescence rate, macro mixing by turbulence, and oxygen transfer from the bubble to the fluid phase. Although the initial bubble size generated by membrane diffusers is reported in few publications, there is a lack of information on the actual bubble size distribution produced by this type of aerators. To investigate on this issue, high precision optical measurement techniques, such as fluidic sensor microscope or videometery are known to be versatile approaches. Hence, the description of the offered task is as follow:

• Acquiring knowledge in the following areas: activated sludge process, optical measurement techniques, mass transfer in two phase flows
• Preparation of the experimental setup
• Conducting the experiment using high-resolution optical measurement techniques.
• Post processing and evaluating the data
• Writing and presenting the results

• Study programs in the fields of process engineering, chemical engineering, mechanical engineering and related degree programs
• Knowledge in the following areas is advantageous: oxygen mass transfer, biological wastewater treatment, optical measurement techniques.
• Enthusiasm for experimental work
• Data analysis in Matlab
• Structured and independent working

The candidate can start from September 2017. The duration of the project can be up to 6 months.