Combining UV and Chlorination for Recycled Water Disinfection
Principal Investigator and Project Manager
Chi-Chung Tang, Ph.D., P.E., Sanitation Districts of Los Angeles County
Disinfection is essential for ensuring the safety and quality of recycled water. Combining disinfectants has recently attracted increasing attention, because of benefits such as disinfection of a wider range of pathogens, improved reliability through redundancy, reduced disinfection byproducts (DBPs), and potential cost savings. Because chlorine and ultraviolet (UV) radiation are the most common disinfectants used at wastewater treatment plants, and because each method has specific disinfection and reaction mechanisms, research was undertaken to evaluate the combination of UV with either free chlorine or chloramines for disinfection of recycled water.
The results from this project indicate that UV combined with chloramines can achieve median total coliform levels below 2 CFU/100 mL and 5-log poliovirus inactivation; the UV/chlorine-ammonia process also generally provided 5-log MS2 inactivation, but the UV/ammonia-chlorine process provided <4-log MS2 inactivation. Free chlorine was a more effective disinfectant than chloramines. Combined UV/free chlorine provided 5-log inactivation of poliovirus and MS2, and median total coliform levels below 2 CFU/100 mL in most of the bench- and pilot-scale experiments.
(2010, 199 pages, 06-015-1)
Foundation subscriber price: 15.00
Non-member price: 45.00