Bachelor Project/Master Project: Improvement of the fluid dynamic field of a microbial electrolysis cell

Currently, a high energy consumption is required to remove all the organic compounds during the treatment of waste water streams. However, the energy stored in the chemical bonds of such organic compounds keeps being unused most of the time. Up to now, only a part of this energy is recovered through an anaerobic digestion process, resulting in the production of methane-rich biogas. In this sense, the novel concept of microbial electrolysis cells (MECs) can make use of the chemical energy contained in the organic matter of waste water streams for the production of high valuable compounds, such as hydrogen, while reducing the concentration of organic acids. However, MECs are still at research stage and it is necessary to improve its performance to get its full commercial availability. One of the aspects that should be optimized is the fluid dynamic field inside of MECs, since it plays a key role in the transport of species from and to the electrodes.

In this context, the proposed Bachelor Project/Thesis aims to determine the influence of the fluid dynamic field on the performance of microbial electrolysis cell, identifying strategies to enhance such fluid field. For it, different diffusers will be designed and manufactured by laser-cutting. Subsequently, the fluid fields generated by these diffusers will be characterized, using

methylene blue as tracer, determining the field from an optical point of view and measuring the residence time distribution of the tracer inside of the cell. Figure 1 shows a experimental example with a tracer. After identifying the most promising diffusers, two MECs will be tested: A reference cell without diffuser and one with the selected diffuser, in order to compare their real electrochemical performances. The electrochemical efficiency will be evaluated based on chronoamperometry, cyclic voltammetry and polarization curve experiments. The control of the experiments will require the measurement of pH, optical density at 600 nm, Chemical Oxygen Demand (COD), organic acids and conductivity, while the exactly composition will be determined by High Performance Liquid Chromatography (HPLC). Therefore, we are looking for a highly motivated students, willing to work in the field of bio-electrochemistry and to contribute in the development of microbial electrolysis cells. Candidates with background in biology and electrochemistry will be preferred

Language:

English

Beginning:

October 2022.

Duration:

6 months

Supervisors:

Prof. Dr.-Ing. habil. Sven Kerzenmacher - kerzenmacherprotect me ?!uni-bremenprotect me ?!.de

Dr. Ing. Ulrich Mießner - miessnerprotect me ?!uni-bremenprotect me ?!.de

Dr. Óscar Santiago Carretero - santiagoprotect me ?!uni-bremenprotect me ?!.de

M.Sc. Marcos Isaac Vázquez Sánchez - ivazquez@uni-bremen.de