The role of ozone in wastewater treatment processes: further degradation of refractory organic compounds; reduction of color and turbidity in effluent; elimination of Escherichia coli and viruses in water; removal of odor from water. Ozone breaks down and decomposes difficult-to-biodegrade macromolecular organic compounds; it opens rings and decomposes benzene, phenol, and their derivatives; it detoxifies and reduces the toxicity of cyanide, pesticide, and other wastewater; it decolorizes by disrupting chromophore groups. Ozone oxidation processes are generally used at the end of the water treatment process to further reduce COD and decolorize the water, ensuring compliance with effluent standards. The upgrade from Grade B to Grade A can be achieved through ozone + filtration processes. This technology is also used in water reuse projects for decolorization and deodorization. Up to now, Guolin has provided approximately 2000 ozone generators for wastewater projects, totaling approximately 15,000 kg, and has served approximately 1000 projects.