Comparison of Mixed Oxidants to Ozone for Disinfection and Reduction of Health Risks from Recalcitrant Compounds

Mixed oxidants generated by the Purizer Process were compared to ozone for the treatment of wastewater effluent for water reuse.Oxidation of methyl tertiary butyl ether (MTBE) was evaluated. A preliminary experiment indicates mixed oxidants destroyed more MTBE than ozone. A 23-ppm solution of MTBE in DI water was treated with ozone and mixed oxidants for 20 minutes and 72% and 83% reductions in MTBE were observed respectively. Samples treated with mixed oxidants were less toxic to microbe populations used to mineralize the remaining MTBE. In Microtox tests, the EC50 after 15 minutes for ozone treated samples and mixed oxidant treated samples were 51.28% and 58.90% respectively. These results indicate the Purizer Process may be a better pretreatment option than ozone for wastewater. This experiment will be repeated and statistically analyzed results will be presented.Disinfection capabilities will also be compared for the two processes—inactivation of enterococci, fecal coliform, and MS2 phage will be compared. A test run of the new experimental apparatus using ozone only produced a reduction from 1.6 × 104 to 20 fecal coliform per liter after continuous dosing for 11 minutes. This experiment will be repeated as will an identical experiment using mixed oxidants. Statistically analyzed results will be presented.In future experiments, additional low and medium pressure UV lamps will be added in line with the contact chamber to compare oxidation and disinfection capabilities of the following processes: ozone, mixed oxidants, ozone coupled with UV, and mixed oxidants coupled with UV. These processes will also be used to evaluate oxidation of target pharmaceutical and personal care product (PPCP) compounds and endocrine disrupting compounds, bisphenol-A, 17b-estradiol, and naproxyn.