Ozone Advanced Oxidation Technology: Innovative R&D and Research Status
Ozone (O3), as a highly efficient oxidant, sterilizer, decolorizer and odor eliminator, has become a core solution for environmental pollution control and water purification; its related technologies are listed as one of the four key technologies of environmental science in the 21st century, widely applied to organic degradation, microbial inactivation and odor control in air and water.
Core principle of the technology
The key to this technology is using a specific electric field to achieve silent discharge, generating ozone on a large scale. In this process, high-energy electrons collide with gas molecules, triggering a series of fundamental physicochemical reactions that activate the gas molecules and form various highly active free radicals. These radicals can effectively catalyze, decompose and transform all kinds of harmful chemicals and pathogenic microorganisms, ultimately degrading them into harmless substances and achieving deep purification of air and water.
Technology applications
In water treatment, this technology is mainly used in various wastewater treatment scenarios, including microbial inactivation, odor removal and removal of soluble organics and other pollutants.
Characteristics of ozone application:
Outstanding oxidation capacity and rapid reaction rates;
Strong inactivation effect on bacteria, viruses, spores and soft-bodied microorganisms;
Oxidative degradation of soluble organics, significantly reducing BOD and COD;
Uses oxygen from air as raw material and converts back into oxygen after action, raising dissolved oxygen without secondary pollution;
Markedly improves the physical and chemical properties of water, with excellent decolorization, deodorization and odor removal;
Produces no toxic by-products such as chloroform or carcinogenic halogenated organics during disinfection, leaving no substances harmful to humans or livestock.
Technical challenges and bottlenecks
Although ozone has a high oxidation-reduction potential (2.07 V, second only to fluorine) and performs remarkably in drinking water disinfection, decolorization and deodorization, it has limitations when treating wastewater alone. First, ozone's reaction with organics is selective; at low doses and short contact times it is difficult to fully mineralize pollutants, and some intermediates inhibit oxidation. Second, ozone production costs are high and utilization efficiency low, driving up operating expenses. Improving ozone utilization and oxidation efficiency has therefore become a global research focus.
Current state of development
In recent years, application research on the ozone deep oxidation method (also called advanced oxidation processes, AOPs) has achieved remarkable breakthroughs worldwide. By combining ozone with other water treatment processes, this technology generates hydroxyl radicals with stronger oxidizing power and lower selectivity (oxidation-reduction potential of 2.80 V). Compared with conventional processes, ozone deep oxidation excels at treating refractory organics, with rapid degradation, compact footprint, high automation, no secondary pollution and low scum and sludge output; it has been successfully extended to food, pharmaceutical, petrochemical, printing and dyeing, steel and water supply industries.
As early as 1896, Meritens first used ozone as a bactericide in drinking water treatment. In 1906, the Bon Voyage water plant in Nice, France was completed - regarded as the origin of drinking water ozonation. Until the late 1970s, ozone technology was still mainly for disinfection, promoted mainly in France. In recent years its applications have kept expanding, showing unique advantages in microbial inactivation, decolorization, deodorization, degradation of refractory organics and enhanced flocculation. It is especially effective in decolorizing dye, printing-dyeing and papermaking wastewater: ozone breaks the macromolecular chromophore structures for efficient color removal. Papermaking wastewater, with high BOD/COD, strong color and odor, contains large amounts of chlorophenols, chloroacetones and chloroform. Part et al. passed 32.4 mg/L ozone through a column reactor with 3 minutes' residence time, achieving complete decolorization of bleaching wastewater.
Wang Yu's team used high-frequency ceramic surface-discharge ozone technology to treat printing-dyeing wastewater; at pH 7-8 and 10 hours of reaction, the COD removal rate reached 86.6% and decolorization 98.4%. The study pointed out that in acidic environments with pH ≤ 7, ozone decomposition can be delayed and hydroxyl radical yield increased, improving utilization efficiency. Jin Lahua's experiments showed ozone can effectively improve the biodegradability of integrated wastewater from automobile plants. At a gas flow of 16 L/h, ozone dosage of 1 kg/h and pH 10, the COD removal rate reached 60% after 2 hours. In addition, ozone is gradually being extended to advanced treatment of municipal wastewater: dosing 10-20 mg/L with 5-20 minutes of contact achieves 40% COD reduction, 70% BOD reduction, 60% SS reduction, 20% ammonia nitrogen reduction, 80% carcinogen reduction and 90% color reduction. Japan's fine ozone bubble device controls bubble diameter at 10-100 microns, increasing gas-liquid contact area by 2000-4000 times and solubility by 5 times, with efficient mixing; it has been successfully used in food, livestock and aquatic product processing wastewater. As the technology keeps upgrading, ozone science has formed an independent industry worldwide, with broad prospects.
Innovation breakthrough
Based on its development of cyclonic dissolved air flotation, SINOKLE Co., Ltd. innovatively integrated the ozone deep oxidation process, forming the proprietary ozone advanced oxidation - cyclonic dissolved air flotation synergy technology. The technology has reached the internationally advanced level and has so far been granted more than ten domestic and foreign patents, including one international patent and three domestic invention patents.
Building on the highly efficient combination of ozone advanced oxidation and cyclonic dissolved air flotation, SINOKLE Co., Ltd. further developed the integrated ozone advanced oxidation - cyclonic dissolved air flotation unit (CDOF), which integrates ultrasonic catalytic ozone oxidation, chemical flocculation, hydrodynamic cavitation, cyclonic separation, dissolved air flotation and many other technologies, greatly improving ozone utilization and accelerating the ozone oxidation reaction; it can reduce pollutants in water (refractory organics, dissolved oil, color, etc.) quickly, efficiently and at low cost. Meanwhile, through ozone oxidation and flocculation, the cyclonic dissolved air flotation can effectively remove colloidal and dissolved organic matter (which flotation alone cannot remove) while greatly improving separation performance, achieving efficient comprehensive treatment of multiple pollutants in various refractory wastewaters.
The photo above shows the CDOF industrial units deployed by SINOKLE for landfill leachate treatment
