The Process of Ozone Technology in Wastewater Treatment

A complete ozone oxidation wastewater treatment system is mainly a system of ozone generators. Ozone is used in various branches of industry to treat all kinds of wastewater. The specific operating conditions vary depending on the type of industry and the type of wastewater. The process of wastewater treatment includes the following five aspects:

(1) Energy Requirements
Energy requirements in ozone treatment processes refer to the demand for electricity, which is mainly used to convert oxygen into ozone energy. Electrical energy is required for preparing feed gas, contacting ozone, and destroying tail gas. It is also used in process treatment instruments and detection facilities.

(2) Preparation of Feed Gas
Ozone is generated from air, oxygen-enriched air, or high-purity oxygen. If air is used to generate ozone, moisture, particulate matter, and oil mist must be removed before it is introduced into the ozone generator. If these impurities are not removed, they can pose a hazard to the ozone generation process.

(3) Ozone Generation
Due to the unstable chemical properties of ozone, it quickly decomposes into oxygen after generation. Therefore, ozone must be generated locally. Currently, the most effective method for producing ozone is through electrical discharge. In an electric field area formed by a high-voltage electrode and a low-voltage electrode, when dry oxygen or air flows through a dielectric chamber formed by electrodes and barrier dielectric materials, under the action of high voltage/high density current, oxygen molecules are formed into oxygen atoms under electron bombardment. Oxygen atoms combine with oxygen molecules to form ozone.

(4) Ozone Contact
The ozone produced by the ozone generator needs an ozone contact reaction system to add ozone to the wastewater and allow it to react with organic matter, bacteria, metal ions, and other substances in the wastewater through chemical reactions and disinfection biochemical reactions. Traditionally, countercurrent baffle contactors are commonly used, with ozone being added in the first or third chamber of the contact pool. Ozone is introduced from the bottom of the first chamber using a porous diffuser or injector. Rapid ozone reactions occur in the first chamber, and then the mixture of wastewater and ozone enters the second chamber for slower reactions. The third reaction chamber is used to complete the slow reaction and decompose the ozone.

(5) Tail Gas Destruction
Since high concentrations of ozone are particularly irritating gases, the tail gas discharged from the contactor should be collected and all residual ozone should be decomposed. In practical applications, how ozone is effectively absorbed by water is a key issue in ozonation wastewater treatment processes. The ozone-water contact reaction system is a process of adding ozone to wastewater and allowing it to react with organic matter, bacteria, metal ions, and other substances in the wastewater through chemical reactions and disinfection biochemical reactions. The reaction effect (i.e., wastewater treatment effect) is related not only to mass transfer but also to the reaction process itself. Different reaction processes should use appropriate contact reaction devices.