Micro-nano bubble (MNB) technology is becoming an increasingly important research direction due to its unique physicochemical properties and wide range of industrial applications. Micro- and nano-scale gas bubbles dispersed in liquids are characterized by a large interfacial area, long residence time in water, high mass transfer efficiency, and the ability to generate reactive species during implosion processes. These properties create significant opportunities for improving the efficiency of water treatment and energy systems. This study presents an analysis of the application of micro-nano bubble technology in water treatment and energy systems. The work focuses on the influence of MNBs on oxygen transfer efficiency, intensification of flow and heat transfer processes, and enhancement of water purification technologies. The potential application of MNBs in energy systems, including combustion improvement, reduction of pollutant emissions, and support for hydrogen-related technologies, is also discussed. The conducted work included the optimization of the operating conditions of the MNB generation system. The implementation of the project required interdisciplinary knowledge in the fields of thermal engineering, thermodynamics, fluid mechanics, and energy machinery. Different technical solutions applicable to the designed system were analyzed, including the arrangement and construction of hydraulic system components. Particular attention was devoted to the optimization of nozzle geometry and its placement within the installation in order to maximize the concentration of generated MNBs in water. The experimental analysis of the developed system was based on dissolved oxygen measurements carried out using an oxygen concentration meter. The obtained results confirmed that nozzle geometry, hydraulic conditions, and system configuration significantly affect the efficiency of MNB generation and oxygen dissolution in water. The performed optimization demonstrated the high potential of micro-nano bubble technology for application in modern water treatment, desalination, and sustainable energy systems.