Ozone, with its core characteristics of strong oxidizing property, broad-spectrum disinfection ability, and no secondary residue, has become one of the core technologies in the field of industrial air purification. It can targeted solve three core problems in industrial scenarios: malodor pollution, degradation of harmful gaseous pollutants, and microbial disinfection. It is widely used in many industrial fields such as chemical industry, pharmaceuticals, food processing, coating, sewage treatment, and waste disposal. It is an important technical support for the up-to-standard treatment of industrial waste gas, workshop environment management and control, and occupational health protection.
Core Mechanisms of Ozone in Industrial Air Purification
The application value of ozone in industrial air purification mainly relies on its strong oxidation properties. Through two reaction pathways of direct oxidation and indirect oxidation, it achieves three core functions: degradation of harmful pollutants, malodor elimination, and microbial inactivation, which accurately matches the diversified needs of industrial air purification.
Degradation Mechanism of Malodorous and Volatile Organic Pollutants
Ozone has an oxidation-reduction potential (ORP) of 2.07 V, which can oxidize and decompose the vast majority of volatile organic compounds (VOCs) and malodorous substances.
For common VOCs in industrial scenarios such as benzene series, aldehydes, ketones, esters, and non-methane total hydrocarbons (NMHCs), ozone can break the unsaturated bonds in their molecules, decompose macromolecular organic compounds into small molecular compounds, and finally oxidize them into carbon dioxide and water.
For malodorous substances such as mercaptans, thioethers, amines, and fatty acids, ozone can quickly destroy their odor-causing functional groups and oxidize them into odorless and low-toxic small molecular substances, eliminating malodor pollution from the root.
For persistent organic pollutants such as polycyclic aromatic hydrocarbons and heterocyclic organic compounds that are difficult to treat by conventional processes, ozone can destroy their stable molecular structure through oxidation reaction, reducing their toxicity and pollution.
Removal Mechanism of Harmful Inorganic Gaseous Pollutants
The waste gas discharged from industrial production often contains inorganic harmful gaseous pollutants such as hydrogen sulfide, ammonia, nitrogen oxides, and sulfur dioxide.
Ozone can quickly oxidize hydrogen sulfide into substances such as sulfur dioxide and sulfate radicals, completely eliminating the highly toxic and malodorous properties of hydrogen sulfide.
For ammonia, ozone can convert it into harmless substances such as nitrate and nitrogen through oxidation reaction, reducing the ammonia concentration and pungent odor in the waste gas.
For acidic gaseous pollutants such as nitrogen oxides and sulfur dioxide, ozone can oxidize them into high-valence oxides. Combined with the subsequent spray absorption process, it can greatly improve the removal efficiency of pollutants and ensure that the waste gas meets the discharge standards.
Microbial Disinfection Mechanism
In the industrial production environment, microorganisms such as bacteria, fungi, viruses, and mold spores in the air are likely to cause product contamination, equipment mildew, and health hazards to operators.
Through oxidation, ozone can directly destroy the cell membrane and cell wall structure of microorganisms, penetrate into the interior of cells, and damage their core life substances such as nucleic acids and enzyme systems, causing irreversible inactivation of microorganisms.
Ozone also has an efficient inactivation effect on highly resistant microorganisms such as mold spores and bacterial spores, solving the pain points of traditional ultraviolet disinfection such as irradiation dead angles and poor effect on molds.
As a gaseous substance, ozone can diffuse to every corner of the workshop and clean room, achieving dead-angle-free air disinfection, and the disinfection effect is not affected by object occlusion.
Core Application Scenarios of Ozone in Industrial Air Purification
Ozone technology can adapt to the waste gas characteristics and environmental control needs of different industrial industries. Its application scenarios cover the whole process from source waste gas treatment, workshop environment purification to end tail gas treatment, and it is a highly versatile technical solution in the field of industrial air treatment.
Ambient Air Purification in Industrial Workshops
Various industrial production workshops often have problems such as harmful gases volatilized during production, malodorous odors, and microbial pollution, which affect the operating environment and the occupational health of personnel.
In machining and hardware manufacturing workshops, ozone can remove the oil mist odor generated by the volatilization of cutting fluid and lubricating oil, kill microorganisms in the air, and improve the air quality of the workshop.
In food and beverage processing workshops, ozone can carry out regular disinfection of workshop air, kill sedimented bacteria and planktonic bacteria, reduce the risk of microbial contamination of products, and eliminate odors generated during production.
In textile printing and dyeing workshops, ozone can decompose harmful gases and odors volatilized from dyes and auxiliaries, improve the workshop operating environment, and reduce the harm of harmful gases to personnel.
In printing and packaging workshops, ozone can degrade VOCs such as benzene series and esters volatilized from inks and adhesives, eliminate pungent odors, and ensure that the workshop air quality meets occupational health standards.
End Treatment of Industrial Organic Waste Gas and Malodorous Gas
Organic waste gas and malodorous gas discharged from industrial production are the focus of environmental protection management and control, and ozone technology is one of the core processes for end treatment of waste gas.
For low-concentration and large-air-volume organic waste gas, the ozone combined with catalytic oxidation process can efficiently degrade VOCs in the waste gas, solving the pain points of frequent replacement of activated carbon adsorption process and high hazardous waste disposal cost.
For high-concentration and refractory organic waste gas discharged from fine chemical and pharmaceutical intermediate production, ozone can be used as a pretreatment process to destroy the stable molecular structure of pollutants, improve the biodegradability of waste gas, and create conditions for subsequent biological and adsorption treatment.
For malodorous waste gas generated by the rubber and plastic processing industry, ozone can quickly decompose odor-causing substances such as amines and sulfides, achieve the dual effects of waste gas deodorization and pollutant degradation, and ensure that the waste gas meets the discharge standards.
Malodor Control in Sewage Treatment Plants and Waste Treatment Plants
Sewage treatment plants, landfill sites, waste incineration plants, and food waste treatment plants are the hardest hit areas of malodor pollution, and also the most widely used scenarios for ozone technology.
Areas such as aeration tanks, sludge dewatering rooms, and anaerobic tanks in sewage treatment plants will volatilize a large amount of malodorous substances such as hydrogen sulfide, ammonia, thioethers, and volatile fatty acids. Ozone can quickly decompose malodorous substances and eliminate odor pollution through two methods: space disinfection and centralized waste gas treatment.
The landfill area and leachate treatment station of the landfill, the storage pit and pretreatment workshop of the waste incineration plant will produce high-concentration and complex malodorous gas. Ozone can carry out centralized oxidation treatment on the collected malodorous waste gas, completely decompose the odor-causing pollutants, and solve the problem of malodor disturbing residents.
Compared with the traditional chemical spray process, the ozone deodorization process has no chemical consumption, no secondary waste liquid generation, higher deodorization efficiency, and more convenient operation and maintenance.
Air Disinfection in Aseptic Environment of Pharmaceutical and Medical Industries
Aseptic workshops and clean rooms in the pharmaceutical industry, and medical device production workshops have extremely strict requirements on the concentration of airborne microorganisms. Ozone is the mainstream technology for air disinfection in clean environments.
In the GMP (Good Manufacturing Practice) clean area of the pharmaceutical workshop, ozone can replace traditional disinfection methods such as formaldehyde fumigation and peracetic acid spraying to achieve dead-angle-free disinfection of workshop air, walls, and equipment surfaces, kill various microorganisms such as bacteria, molds, and spores, and meet the cleanliness requirements of GMP specifications.
After disinfection, ozone can decompose into oxygen by itself without any harmful residues, will not pollute medicines and production equipment, and also avoid the residual risk of chemical disinfectants.
It can realize automatic timed disinfection during non-production hours without personnel operation, does not affect the normal production process, and the disinfection effect is stable and controllable.
Waste Gas Purification in Coating and Printing Industries
The coating and printing industries are key industries for VOCs emissions. The waste gas contains a large number of organic pollutants such as benzene series, esters, alcohols, and ethers. Ozone technology is an important technical path for the treatment of such waste gas.
In automobile coating and hardware spraying workshops, ozone can treat the organic waste gas discharged from drying rooms and spray booths, degrade VOCs pollutants, and eliminate the pungent odor generated by paint volatilization.
For the ink waste gas discharged from gravure and flexo printing links in the printing industry, the ozone combined with photocatalysis and catalytic oxidation process can efficiently degrade VOCs in the waste gas, greatly reduce the pollutant concentration, and meet the industry emission standards.
It can be used together with the existing spray and filtration systems for waste gas treatment, without large-scale transformation of the existing production lines, with low transformation cost and stable treatment effect.
Odor Control in Livestock Breeding and Feed Processing Industries
Large-scale livestock farms and feed processing plants will produce a large amount of waste gas containing malodorous substances such as ammonia, hydrogen sulfide, volatile organic acids, and skatole, which are an important source of agricultural non-point source pollution.
In the barns and manure treatment areas of farms, ozone can decompose malodorous substances through two methods: space disinfection and centralized waste gas treatment, while killing pathogenic bacteria in the air, reducing the risk of livestock epidemic transmission, and improving the breeding environment.
In the raw material workshop and production workshop of the feed processing plant, ozone can eliminate the fishy smell generated by raw materials such as fish meal and meat and bone meal, kill mold spores, avoid feed mildew, and improve the workshop operating environment.
Compared with traditional deodorant spraying, ozone deodorization has no chemical residue, long duration of action, and lower comprehensive operation and maintenance cost.
Mainstream Processes and System Forms of Ozone Application in Industrial Air Purification
According to the air volume, concentration, pollutant composition of industrial waste gas, as well as the different needs of environmental purification, ozone technology has formed a variety of mature application processes and system forms, which can accurately adapt to the treatment needs of different scenarios.
Gas Phase Direct Oxidation Process
This process is the most basic and commonly used ozone application process for industrial air purification.
The core principle is to dose ozone directly into the waste gas or air to be treated, so that ozone and pollutants can fully contact in a closed reaction chamber, pipeline or space, and complete pollutant degradation and microbial disinfection through oxidation reaction.
The process is characterized by simple process flow, low equipment investment, convenient operation and maintenance, and no need for additional chemicals and auxiliary materials.
It is suitable for scenarios such as malodorous gas treatment, workshop environment disinfection, low-concentration VOCs waste gas treatment, and aseptic space disinfection.
The core control parameters are ozone dosage and contact reaction time between ozone and pollutants, which need to be accurately matched according to the pollutant concentration.
Ozone Catalytic Oxidation Process
This process is the mainstream upgrading process for the current industrial organic waste gas treatment, which is divided into two categories: homogeneous catalysis and heterogeneous catalysis, and heterogeneous catalytic oxidation is the main type in industrial applications.
The core principle is to add solid catalysts into the ozone oxidation system. Through the adsorption and catalysis of the catalyst, it strengthens the decomposition of ozone to generate hydroxyl radicals, and improves the oxidation reaction efficiency and pollutant degradation effect.
Most catalysts use activated alumina, molecular sieve, and activated carbon as carriers, and load active metal components such as manganese, iron, copper, and cerium, which can targeted improve the degradation efficiency of specific pollutants.
The process is characterized by high oxidation efficiency, high ozone utilization rate, few by-products, and can treat organic pollutants that are difficult to degrade by conventional ozone oxidation.
It is suitable for scenarios such as advanced treatment of medium and low concentration organic waste gas, treatment of refractory malodorous gas, and waste gas standard upgrading and retrofitting.
Ozone-UV Photo-Oxygen Synergistic Process
This process combines the technical advantages of ozone oxidation and ultraviolet photocatalysis, and is a widely used combined process in industrial waste gas treatment.
The core principle is that through ultraviolet irradiation, on the one hand, it stimulates the decomposition of ozone to generate hydroxyl radicals with stronger oxidation capacity, on the other hand, it stimulates the breaking of molecular bonds of pollutants in the waste gas, improves the oxidizability of pollutants, and forms a synergistic oxidation effect.
Compared with single ozone oxidation or single photo-oxygen process, the pollutant degradation efficiency of the synergistic process can be increased by more than 30%, with lower ozone dosage and better operating energy consumption.
It is suitable for the treatment of medium and low concentration VOCs waste gas and malodor elimination in industries such as printing, coating, and electronics.
Ozone Scrubbing Combined Process
This process combines ozone oxidation with wet spray scrubbing, and is a commonly used process for treating industrial waste gas with complex components, dust and high humidity.
The core process flow is: the waste gas to be treated first passes through the spray scrubber to remove dust and water-soluble pollutants; then it enters the ozone oxidation section to complete the degradation of insoluble organic pollutants and malodorous substances; ozone can also be directly added into the washing liquid to prepare ozonated water, and the oxidation and absorption of pollutants are completed simultaneously during the spray process.
The process is characterized by the simultaneous treatment of particulate matter, water-soluble pollutants, insoluble organic pollutants and malodorous substances in the waste gas, with an integrated treatment process and strong adaptability.
It is suitable for the treatment of high-humidity and dust-containing malodorous waste gas with complex components in sewage treatment plants, waste treatment plants, and chemical industries.
Core Advantages of Ozone Technology for Industrial Air Purification
Compared with traditional technologies in the field of industrial air purification such as activated carbon adsorption, chemical spray, plasma, and ultraviolet disinfection, ozone technology has irreplaceable comprehensive advantages, which meet the core needs of industrial environmental protection treatment and environmental management and control.
Wide Treatment Range and Strong Broad Spectrum
Ozone can simultaneously achieve four major functions: organic pollutant degradation, inorganic harmful gas removal, malodor elimination, and microbial disinfection. One set of system can solve multiple types of problems in industrial air purification.
It has high-efficiency treatment effect on most gaseous organic pollutants, inorganic harmful substances, and microorganisms, breaking through the limitation that traditional processes can only treat a single type of pollutant.
It has extremely strong adaptability, and can cover the needs of industrial air purification and waste gas treatment in different industries, different concentrations, and different air volumes.
No Secondary Pollution, Green and Environmental Friendly
The final decomposition product of ozone is oxygen, and the final products of the oxidation reaction are mostly harmless substances such as carbon dioxide, water, and inorganic salts, without toxic and harmful residues.
There is no need for continuous dosing of chemical agents, no secondary waste liquid and waste residue will be generated, and a large amount of hazardous waste will not be generated like the activated carbon adsorption process, which greatly reduces the subsequent pollutant disposal cost and environmental protection risk.
It is in line with the current environmental protection development requirements of green, low-carbon, pollution and carbon reduction in the industrial field.
High Treatment Efficiency and Stable Effect
The ozone oxidation reaction is fast, and the pollutant degradation and microbial inactivation can be completed within seconds to minutes, with short equipment retention time and small floor area.
The removal rate of malodorous substances can reach more than 95%, the degradation efficiency of common VOCs can reach more than 80%, and the inactivation rate of microorganisms can reach 99.99%, with stable and reliable treatment effect.
Gaseous ozone can achieve dead-angle-free diffusion, solving the problem of treatment dead angles existing in traditional disinfection and purification processes, and ensuring the overall treatment effect.
Convenient Operation and Maintenance, Controllable Comprehensive Cost
Ozone can be produced on-site and used immediately, without the need for storage and transportation of chemical agents, avoiding the safety risks and management costs of hazardous chemical management.
The ozone generation system has a high degree of automation, can realize unattended operation, and the daily operation and maintenance only need to check the equipment status regularly, and the operation and maintenance workload is much lower than that of traditional processes.
Although the upfront equipment investment of the ozone system is higher than that of some traditional processes, the long-term operation cost of chemicals, consumables, labor, and hazardous waste disposal is extremely low, and the comprehensive cost advantage of the full life cycle is significant.
Strong Process Adaptability, Convenient Upgrading and Retrofitting
The ozone process can be used alone, or flexibly combined with traditional processes such as spraying, filtration, photocatalysis, biological method, and activated carbon adsorption to build an efficient composite treatment system.
It can be directly upgraded and retrofitted with the existing industrial waste gas treatment system and workshop ventilation system, without large-scale modification of existing facilities, with low transformation cost and short implementation cycle.
Equipment specifications can be flexibly customized, which can be perfectly adapted from small workshop disinfection equipment to large-scale industrial waste gas treatment systems.
Key Technical Specifications and Safety Control of Ozone Purification for Industrial Air
Ozone has both strong oxidizing property and health hazard. In the application of industrial air purification, we must strictly follow the safety specifications and technical standards, so as to hold the bottom line of occupational health and production safety while ensuring the treatment effect.
Precise Control of Ozone Dosage and Reaction Parameters
Ozone dosage is the core parameter that determines the treatment effect and operation safety. It must be accurately calculated and dynamically adjusted according to the pollutant concentration, air volume, and composition of the gas to be treated.
Insufficient dosage will lead to incomplete degradation of pollutants and failure to meet the treatment requirements; excessive dosage will cause ozone escape, waste of operating energy consumption, and lead to the problem of excessive ozone in the tail gas.
It is necessary to ensure sufficient contact reaction time between ozone and pollutants. Conventional oxidation reaction needs to ensure that the contact time is not less than 2 seconds, and the treatment of refractory pollutants needs to be extended to more than 5 seconds to ensure the full completion of the reaction.
It is recommended to be equipped with online pollutant concentration monitoring and ozone concentration monitoring equipment to realize real-time dynamic adjustment of ozone dosage, taking into account both treatment effect and operation economy.
Control of Ozone Residue Elimination in Tail Gas
If there is unreacted ozone remaining in the tail gas after the oxidation reaction, direct discharge will cause air pollution and also harm the health of surrounding personnel.
All industrial ozone air purification systems must be equipped with a complete ozone tail gas destruction device to ensure that the ozone concentration in the discharged gas meets the requirements of emission standards.
The mainstream ozone tail gas destruction methods are divided into two categories: one is the catalytic decomposition method, which can quickly decompose the residual ozone into oxygen through the ozone decomposition catalyst, with a decomposition efficiency of more than 99%, no secondary pollution, and is the preferred solution for industrial applications; the other is the activated carbon adsorption method, which removes residual ozone through the adsorption and decomposition of activated carbon, and is suitable for the treatment of small air volume and low concentration ozone tail gas.
The ozone concentration in the discharged tail gas must comply with the relevant national standards such as the Integrated Emission Standard of Air Pollutants, and excessive emission is strictly prohibited.
Operating Environment Safety Protection Specifications
Ozone has strong irritation to the human respiratory tract, eyes and skin. China’s Occupational Exposure Limits for Hazardous Agents in the Workplace (GBZ 2.1-2019) clearly stipulates that the 8-hour time-weighted average allowable concentration of ozone in the air of the workplace is 0.15 mg/m³, and the short-term exposure allowable concentration is 0.3 mg/m³.
It is strictly prohibited to dose high-concentration ozone for air disinfection in a closed space with personnel working. Workshop environment disinfection must be carried out during non-production hours after personnel evacuation. After disinfection, it is necessary to ventilate and stand for sufficient time, and personnel can only enter after the ozone is completely decomposed.
The ozone equipment room and ozone reaction chamber must maintain good ventilation, and install an online ozone leakage monitoring and alarm device with an alarm threshold set at 0.15 mg/m³. The alarm device must be linked with the emergency shutdown and forced ventilation system.
Operators must receive professional training, be familiar with the safety risks and emergency disposal methods of ozone, and must wear qualified personal protective equipment when entering areas where high-concentration ozone may leak.
Equipment Operation and Maintenance and System Safety Design
Ozone generation equipment, dosing system, concentration monitoring equipment, and tail gas destruction device must be regularly calibrated, maintained, and serviced to ensure stable equipment operation and precise and controllable parameters.
Ozone has strong corrosiveness. The pipelines, reaction chambers, valves and other components of the system must be made of ozone corrosion-resistant materials such as 304/316 stainless steel, fluororubber, and polytetrafluoroethylene, to avoid corrosion and leakage problems during long-term operation.
The gas source of the ozone preparation system must be strictly controlled, using dry and clean oxygen or air, and the dew point of the gas source must meet the equipment requirements to avoid affecting the ozone generation efficiency and the service life of the equipment.
The system must be equipped with a complete safety interlock protection mechanism, including overload protection, overheat protection, undervoltage protection, leakage interlock shutdown and other functions, to eliminate safety accidents caused by equipment failure.
Existing Bottlenecks and Precautions for Ozone Application in Industrial Air Purification
Existing Technical and Application Bottlenecks
High energy consumption in low-concentration and large-air-volume scenarios. For ultra-low concentration and ultra-large air volume industrial waste gas, the energy consumption per unit pollutant treatment of the ozone oxidation process is relatively high, and the operating cost is not competitive, which needs to be further optimized through the catalytic synergistic process.
Limited treatment efficiency for some refractory pollutants. For organic pollutants with extremely stable chemical properties such as perfluorinated compounds and chlorinated hydrocarbons, the degradation effect of a single ozone oxidation process is poor, and it needs to be treated in coordination with high-temperature catalysis, advanced reduction and other processes.
High requirements for by-product prevention and control. When treating organic pollutants containing nitrogen, chlorine and bromine, ozone oxidation may generate by-products such as nitrogen oxides, acyl chloride, and bromate. It is necessary to strictly control the reaction conditions and support the by-product removal process, which increases the complexity of application.
High difficulty in precise control. In the industrial production process, the air volume and pollutant concentration of the waste gas fluctuate greatly. The conventional ozone system with fixed dosage is difficult to quickly adapt to the changes of working conditions, which is prone to the problem of substandard treatment effect or excessive ozone dosage.
Core Application Precautions
It is strictly prohibited to illegally dose ozone in a closed space where personnel are working. The principle of “disinfection when unoccupied, entry after ventilation” must be strictly followed to eliminate the risk of personnel ozone poisoning.
It is necessary to accurately design the ozone dosage and reaction parameters according to the pollutant composition and concentration of the waste gas, conduct laboratory tests in advance to verify the treatment effect, and avoid poor effect or excessive by-products caused by blind dosing.
It is strictly prohibited to mix ozone with flammable and explosive gases and volatile organic solvents in a closed space to avoid the risk of combustion and explosion caused by the reaction of high-concentration ozone and organic matter.
For waste gas with high humidity and high dust content, dust removal and dehumidification pretreatment must be carried out first to avoid dust and water vapor affecting the ozone oxidation efficiency, and at the same time protect the ozone generation equipment and catalyst.
The activity of the catalyst needs to be checked regularly. When deactivation, poisoning or blockage occurs, it should be replaced or regenerated in time to ensure the stable effect of catalytic oxidation.
Development Trend of Ozone in the Field of Industrial Air Purification
With the continuous tightening of China’s environmental protection emission standards, the management and control requirements for malodor pollution and VOCs treatment of industrial enterprises are continuously improved, and the attention of industrial production to workshop environment and occupational health is continuously increased, which promotes the continuous upgrading and optimization of ozone industrial air purification technology. The core development trends are concentrated in the following directions.
Upgrading of low-energy ozone production equipment. The industry is accelerating the research and development of high-frequency, high-voltage, low-energy ozone generators, improving ozone production efficiency, reducing the power consumption and production cost per unit of ozone, and broadening the application space of ozone technology in large-air-volume and low-concentration waste gas treatment scenarios.
Iterative research and development of high-efficiency catalytic materials. For the ozone catalytic oxidation process, research and develop heterogeneous catalysts with high activity, high stability, long service life and low cost, improve the generation efficiency of hydroxyl radicals, develop targeted catalysts for specific industrial pollutants, reduce ozone dosage, and improve the treatment efficiency of refractory pollutants.
Research and development of intelligent precise control system. Combined with online waste gas concentration monitoring, ozone concentration monitoring, Internet of Things, and AI algorithms, it can realize real-time dynamic adjustment of ozone dosage, adapt to the fluctuation of industrial production conditions, minimize operating energy consumption on the premise of ensuring that the treatment effect meets the standard, and eliminate the safety risk of excessive ozone dosage.
Construction of multi-technology coupling collaborative system. Promote the in-depth coupling of ozone oxidation technology with catalytic combustion, biological method, photocatalysis, low-temperature plasma, membrane separation and other technologies, build a whole-process collaborative treatment system of “pretreatment-core treatment-advanced treatment”, achieve comprehensive optimization of treatment effect, operating cost and carbon emission, and adapt to increasingly stringent environmental protection emission standards.
Optimization of by-product precise prevention and control technology. For the harmful by-products that may be generated during the ozone oxidation process, research and develop supporting technologies for precise control of reaction conditions and directional decomposition of by-products, to avoid the risk of by-products from the source, and improve the environmental protection safety of the process.
Improvement of industry application specifications and standards. With the wide application of ozone technology in the field of industrial air purification, the relevant process design specifications, equipment standards, safety operation specifications, and pollutant treatment effect evaluation standards will continue to be improved, promoting the standardized development of the industry, and further releasing the potential of technology application.
