HIPOX™ OZONE-PEROXIDE ADVANCED OXIDATION WATER TREATMENT SYSTEM FOR THE DISINFECTION OF WASTEWATER AT A LOS ANGELES COUNTY SANITATION DISTRICT JOINT WATER POLLUTION CONTROL PLANT

Many water pollution control plants in the State of California discharge primary and secondary treated wastewater to the ocean. In order to protect beaches, sensitive aquatic habitats, and marine life from bacterial pathogens, the wastewater is disinfected, usually with sodium hypochlorite, prior to discharge. However, increased environmental sensitivity to disinfection byproducts such as trihalomethanes (THMs) as well as reduction in NPDES permitted chlorine residuals has compelled many water pollution control plants to explore alternative disinfection technologies.The Los Angeles County Sanitation District (LACSD) is examining the effectiveness of ozone or ozone and hydrogen peroxide (peroxone) as a disinfection alternative to sodium hypochlorite and has been working with Applied Process Technology (Applied) to conduct a four-month demonstration project at a Joint Water Pollution Control Plant. Results achieved during this demonstration indicate that the HiPOx technology is a viable disinfection alternative.For this project, Applied deployed a compact 10-gpm HiPOx HCU system with a 8' by 4' footprint. The HiPOx system is equipped with multiple reactors where injection of reagents can be individually controlled. This allows the HiPOx system to function in various modes: 1) using ozone only; 2) as an advanced oxidation process (AOP) using ozone and hydrogen peroxide; or 3) as a combination system that uses advanced oxidation in some reactors and ozonation in other reactors. Its process flexibility makes HiPOx an effective technology for treating a wide range of applications.During the demonstration, excellent and efficient bacterial reduction was achieved, particularly when HiPOx was operated in an ozone-only mode. Bacterial concentrations were reduced 2.5 logs, meeting the NDPES discharge limit for this application with 4.8 mg/l of applied ozone. Bacterial concentrations were reduced 3.0 logs with 7 mg/l of applied ozone.