UV Hydrogen Peroxide Advanced Oxidation Process

In the UV hydrogen peroxide process UV spectrum photons react with hydrogen peroxide to form hydroxyl radicals as shown by the simplified reaction below:

H₂O₂→ 2 •OH (in the presence of UV light)

The major components of a UV/H₂O₂ system include: UV lamps, lamp sleeves, and lamp cleaning system, hydrogen peroxide storage and injection system, reactor chamber, in-line mixer, supply and discharge pumps and piping, monitoring and control systems. For the UV/H₂O₂ system, higher radical generation results from the use of MP-UV lamps relative to the LP-UV lamps, due to the better absorptivity of H₂O₂ at lower wavelengths (see a brief discussion of UV lamps for industrial water treatment).

The key design and operating parameters include the H₂O₂ dose, the UV lamp type and intensity, the reactor contact time, and the control systems (pH and temperature). The UV quartz sleeve cleaning frequency is a function of iron and other materials which could form scale on the tubes. The optimum dose of H₂O₂ should be determined for each water source based on bench and pilot-scale testing, but is commonly estimated at twice the TOC and not less than 1 to 2 mg/L.

Advantages of the UV/H₂O₂ system

The advantages and disadvantages of the UV/H₂O₂ system are: MP-UV irradiation can serve as an effective disinfectant for a variety of microorganisms in addition to activating the peroxide for organic destruction.

H₂O₂ is highly soluble and can be added to the source water at high concentrations, whereas O₃ is a much less soluble gas that must be bubbled into the source water. Consequently, UV/H₂O₂ processes can generate larger amounts of hydroxyl radicals than O3/UV processes for equal amounts of energy used to add the oxidants to the source water.

Disadvantages of the UV/H₂O₂ system

UV light penetration can be adversely affected by high turbidity and elevated nitrate concentrations and the tubes can become fouled with scale.

The theoretical yield of hydroxyl radicals via the UV/H₂O₂ process is greater than that for the H₂O₂/O3 process; however, due to interfering compounds in the water, this theoretical yield can be decreased to below that of the H₂O₂/O3 process. The presence of residual hydrogen peroxide in the water may require removal down stream of the process.

Overall, it’s important to consider the water composition, treatment goals, UV dose and cost. Spartan has the experience to help you determine the appropriate solution to meet your water treatment goals. Contact us today or request a quote.