Study On Removing Typical Odorants In Drinking Water By Advanced Oxidation Technology Of Ultraviolet Combined With Hydrogen Peroxide

In recent years,with the improvement of people's living standard and the aggravation of source water eutrophication,the ordor problem of drinking water has been increasingly concerned.The typical odorants in drinking water are 2-methylisoborneol?2-MIB?and geosmin?GSM?,which can't be effectively removed by the conventional water treatment processes.To find out the effective and efficient ordor control technologies,the advanced oxidation process of ultraviolet combined with hydrogen peroxident?UV-H₂O₂?was mainly focused in this study,the gas chromatography mass spectrometry?GC/MS?based on the MS multiple reaction monitoring mode?MRM?was developed,the performance,influencing factors and dynamic model of removing 2-MIB and GSM under various oxidation conditions were investigated,the inorganic by-product of oxidizing odorants with VUV/H₂O₂ was tested and the energy cost of oxidation was also analyzed.?1?Aiming at 2-MIB and GSM,the GC/MS analysis method based on the MS multiple reaction monitoring mode?MRM?was developed and optimized.The enriched concentrations of odorants were increased and the accuracy of analyzing odorants was improved with this developed method.Method Detection Limits?MDLs?of 2-MIB and GSM were 0.7290 ng/L and 1.0374 ng/L,the average recovery rate ranges of 2-MIB and GSM were 92% 108% and 88% 104%,relative standard deviations of 2-MIB and GSM were less than 6.5% and 9.0% respectively.?2?Compared with the solo ultraviolet photo-oxidation and solo oxidation with hydrogen peroxident,the effectiveness of removing 2-MIB and GSM with UV/H₂O₂ was remarkably improved,and the reaction of degrading 2-MIB and GSM can be expressed with one-order reaction model.Increasing concentration of hydrogen peroxident and intensity of ultraviolet could increase the reaction rates of photo-oxidizing 2-MIB and GSM.Background organic matters and inorganic ions in the raw water could reduce the photo-oxidation rates of 2-MIB and GSM.Acidic condition would favor the photo-oxidation of 2-MIB and GSM with UV/H₂O₂.Alkalinity,tert-Butanol and humic acid could inhibit the photo-oxidation of 2-MIB and GSM with UV/H₂O₂ to different degrees.?3?Compared with UV/H₂O₂,advanced oxidation process of mixed ultraviolet combined with hydrogen peroxident?VUV/H₂O₂?can induce ozone by ultraviolet with wavelength of 185 nm,more hydroxide radical can be produced synergistically,which can strengthen the performance of photo-oxidizing 2-MIB and GSM.The dose of hydrogen peroxident,ultraviolet intensity,pH value,alkalinity,tert-Butanol and humic acid influenced the removal of 2-MIB and GSM with VUV/H₂O₂ in the similar way of UV/H₂O₂.?4?Under typical odorant concentrations of 100 ng/L in the raw water,VUV/H₂O₂ could not cause the nitrite concentration exceed the limiting value in drinking water.The energy efficiency of oxidizing 2-MIB and GSM with UV/H₂O₂ was evaluated with the index of power input per log reduction level(E_E0),and the energy cost could be reduced by adjusting the reaction conditions appropriately.