Our research group has developed a nano bubble ecological restoration technology for urban enclosed and semi-enclosed heavily polluted black and odorous water bodies. This technology does not involve the addition of chemicals or microorganisms and is environmentally friendly: 1) Nano bubbles have a huge specific surface area, slow rising speed, and self-compression effect, which can greatly promote the mass transfer rate of oxygen between gas and liquid, achieving efficient oxygenation of the water body. At the same time, the slow rising speed of nano bubbles will not cause vertical disturbance to the water body. Therefore, the dissolved oxygen concentration in the bottom layer of the water body can be effectively improved without causing the sedimentation to float up. (Separation and Purification Technology. 193, 20, 408-414, 2017;) 2) The forced bursting technology of nano bubbles forms strong oxidizing free radicals, which directly oxidize macromolecular organic substances in water into small molecular organic substances. It is more conducive to the degradation of organic matter by microorganisms under aerobic conditions. (Chemosphere. 220, 1067-1074, 2019; Ultrasonics Sonochemistry, 22, 132-138, 2014) 3) The pressure gradient generated during the formation of nano-bubbles causes the rupture of gas vesicles within algal cells, damages photosynthesis, and leads to a rapid decline in activity, inhibiting algae reproduction. (Water Research, 62, 241-248, 2014; Chemosphere, 136, 245, 2015) 4) Ultra-small diameter nano-bubbles have long-term stability and can diffuse and penetrate into the bottom mud through Brownian motion, increasing the dissolved oxygen and redox potential levels of the bottom mud, effectively regulating the interfacial behavior of pollutants. In situ remediation of bottom sediments significantly reduces dredging costs. (Patent CN 108726824 A) Figure 1 The stability and low cost of the nano-bubble technology for remediating black and odorous water bodies are key to the treatment technology. However, existing technologies mainly rely on multiphase flow pumps to provide pressure for gas-liquid mixing, with bubbles generally being micron-sized and resulting in high energy consumption and extremely low efficiency. Moreover, due to the small space inside the pump body, damage to the impeller often occurs in black and odorous water bodies containing a large amount of silt and debris, leading to instability. High-performance multiphase flow pumps essentially depend on imports, which are expensive and require significant investment. Our research group uses ordinary sewage submersible pumps as fluid conveying equipment and achieves efficient gas dissolution and rapid separation of residual gases through independently developed high-efficiency phase balance and mesoporous gas disperser. By using a two-stage release system to enhance the local pressure drop and increase the local liquid flow velocity gradient, the generation of microbubbles is inhibited, resulting in the preparation of high concentrations of nanobubbles. This technology overcomes the bottleneck of generating a large number of microbubbles using multiphase flow pumps, and can produce high concentrations of nanobubbles in natural water bodies. It is suitable for treating natural water bodies containing a large amount of solid particles, has strong stability, and low energy consumption. The pump body does not rely on an inlet, greatly reducing the equipment cost. For black and odorous water bodies with different degrees of water quality pollution, by regulating operating conditions such as bubble size, gas inside the bubble, and gas-liquid mixing hydraulic conditions, a complete set of generation equipment (as shown in Figure 2) and key treatment technologies have been developed. These can temporarily improve water body transparency and dissolved oxygen levels, and long-term restore bottom sediments to enhance water quality. Figure 2 shows the nanobubble generation equipment. Fourth, Market Analysis According to the '2014 Micro and Nano Bubble Industry Association of Japan' report, "Micro-Nano Bubble Technology Economic and Market Overseas Survey": By 2023, the market capacity of industries related to micro-nano bubble technology is expected to reach 380 billion RMB (64 trillion yen) (Figure 3). Global demand for products and services utilizing micro-nano bubble technology will begin to grow around 2017, and in the coming 20 years, it is expected to reach a trillions of RMB level market; in the future, micro-nano bubbles have an extremely huge market space in the fields of environmental protection and agriculture. In the environmental field, they can be used for water purification, biological wastewater treatment, soil remediation, etc., with broad application prospects. Figure 3 "Micro-Nano Bubble Technology Economic and Market Overseas Survey" Micro-Nano Bubble Market Forecast