Impact of hydrogen peroxide on nitrite formation during UV disinfection

• Published in: Water research (Oxford) 2003-11, Vol.37 (19), p.4730-4736
• Main Authors: Sharpless, Charles M., Page, Margaret A., Linden, Karl G.
• Format: Article
• Language: English
• Subjects: Advanced oxidation; Applied sciences; Disinfection - methods; Drinking water and swimming-pool water. Desalination; Exact sciences and technology; hydrogen peroxide; Hydrogen Peroxide - chemistry; Hydrogen-Ion Concentration; Hydroxyl Radical - chemistry; Medium pressure UV lamp; Nitrate; Nitrites - analysis; Oxidants - chemistry; Pollution; Ultraviolet Rays; UV byproducts; Water Purification - methods; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(03)00442-1

One concern with UV disinfection of water is the production of nitrite when polychromatic UV sources are utilized. Based on previous work, it was hypothesized that a small addition of hydrogen peroxide (H 2O 2) may be useful in controlling nitrite during UV disinfection. However, it was found that H 2O 2 addition (5 or 10 mg/L) during polychromatic UV irradiation of drinking water at doses used for disinfection significantly increases the levels of nitrite produced relative to solutions without H 2O 2. Enhancement rates ranged from approximately 15% to 40% depending upon pH and H 2O 2 concentration; the relative increase in the NO 2 − yield was greater at pH 6.5 than at pH 8.3. The observed effects are tentatively ascribed to a combination of enhanced superoxide production and increased hydroxyl radical scavenging when H 2O 2 is added. These results indicate that H 2O 2 cannot be used to control nitrite production during UV disinfection and that enhanced nitrite formation will occur if H 2O 2 is added during UV water treatment to achieve advanced oxidation of contaminants.