Nowadays we are increasingly aware of the need for energy and the impact we have on the environment. Harmful substances enter water sources, endangering human health and negatively affecting the environment. These substances need to be removed to keep the water clean, while at the same time striving to minimize energy consumption at wastewater treatment plants. Hydrodynamic cavitation has proven to be a potential technology as it is one of the green oxidation processes, which means that it has a lower negative impact on the environment compared to other treatment technologies. However, the use of cavitation for wastewater treatment is still relatively unexplored and the mechanisms responsible for the positive effects need to be investigated first. This Master's thesis concentrates on optimizing the cavitation generator geometry, aiming at altering the cavitation conditions and, consequently increasing the chemical effects. In order to investigate the effects of the geometry, we performed high-speed camera visualization and simultaneous measurements of pressure pulsations. The experiments were carried out on different liquid samples: salicylic acid solution, H2O2+ RR120 solution, H2O2 solution, RR120 dye solution, and water. We found that the chemical effects of cavitation depend on the cavitation conditions, which are influenced by the geometry of the rotor, and that there is a correlation between the formation of OH radicals and the decomposition of H2O2.
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