Ozone catalytic oxidation technology is an advanced oxidation process widely used for the treatment of landfill leachate and other refractory wastewater. This article introduces its technical background, principles, features, and application scope.

Technical Background

The government has successively issued the "Water Ten Plan" and the "Guidelines for the Remediation of Urban Black and Odorous Water Bodies," setting timelines for improving national water environmental quality. Local governments have also introduced pollutant discharge standards for wastewater treatment plants. A core indicator is the reduction of COD concentration in water — according to different standard requirements, down to 50 mg/L, 30 mg/L, and even below 20 mg/L to achieve reuse value. Advanced oxidation technologies are increasingly applied in the advanced treatment stage of wastewater treatment plants, especially ozone catalytic oxidation, which replaces Fenton to avoid generating large amounts of sludge and sludge treatment costs.

Ozone has strong oxidizing properties and decomposes rapidly in water within a very short time, with no secondary pollution from by-products, making it an ideal green oxidizing agent. With the continuous development and maturation of ozone generation technology, ozone oxidation has gradually become a widely applied advanced oxidation technology. In the water treatment industry, it has been applied in disinfection, deodorization, taste and color removal, iron and manganese removal, oxidation and decomposition of organic matter, and flocculation.

Because ozone is chemically unstable and easily decomposes under normal conditions, it is difficult to store and transport for long periods. Therefore, ozone is usually generated on-site by discharging air or oxygen. Since this process consumes a large amount of electrical energy, improving ozone generation efficiency and the utilization rate of the produced ozone is an important topic for ozone oxidation in the water treatment industry.

Technical Principle

Ozone oxidation: The mechanism utilizes the oxidizing property of ozone (oxidation potential 2.03V) to directly oxidize organic matter in water, or to decompose macromolecular organic matter into smaller molecules, making them easier to degrade. Although pure ozone oxidation can remove organic matter to a certain extent, it has difficulty further oxidizing the small molecules after oxidation, so pure ozone oxidation has certain limitations on the mineralization of organic matter.

Ozone catalytic oxidation: By adding a catalyst to the ozone system, the ability to generate hydroxyl radicals and the ability to directly oxidize organic matter with ozone can be significantly improved. It is a new technology developed to address the low efficiency of ozone oxidation alone.

Technical Features

1. Technical core: The key to this process is the ozone catalyst.

2. Process characteristics:

- Simple process: short process flow, easy to operate.

- Stable process: ozone and ozone catalytic oxidation processes are mature and stable.

- Low investment and operating costs: compared with other advanced oxidation processes, ozone catalytic oxidation has lower investment and operating costs.

- Wide application scope: can be widely used in advanced upgrading and biochemical pretreatment.

- Green and environmentally friendly: the process requires no chemical reagents, produces no solid waste, and belongs to a "new" green process.

Application Scope

This process targets the pretreatment and advanced treatment of high-concentration, high-toxicity, high-color, and refractory biodegradable wastewater, and can greatly reduce wastewater color and COD at low cost, improving the biodegradability of wastewater.

- Petroleum wastewater, landfill leachate, chemical dyes, pharmaceutical wastewater: after biochemical treatment with ozone catalytic oxidation, the COD value drops significantly.

- Landfill leachate, printing and dyeing wastewater, leather wastewater: good application for decolorization, with obvious COD removal.

Advanced treatment using an integrated ozone catalytic oxidation – dissolved air flotation process has low investment and operating costs and good results.