Methods for treating odors

A method for treating a gas having an undesirable odor, said method comprising:

• contacting said gas with an basic aqueous oxidizing composition having a pH of about 9.0 to about 10.0, and comprising H2O2 at a concentration of about 20 mg/L to about 700 mg/L, wherein said contacting includes mixing said gas with said basic oxidizing composition so as to at least partially dissolve at least one compound contained in said gas into said basic oxidizing composition, said gas and said basic oxidizing composition being mixed together in a packed column, and wherein said gas is introduced at a bottom portion of said column and said basic aqueous composition is introduced at a top portion of said column, said gas and said basic aqueous composition being mixed together into said column over a predetermined amount of transfer units and
• submitting said gas and said composition to UV radiation when said gas and said composition are contacting each other, wherein said treatment permits to reduce by at least 60% intensity of said undesirable odor, as determined by dynamic olfactometry measurements carried out by a panel of individuals, in which the olfactometer was composed of six beakers in which three test specimens were found, each beaker corresponded to a different dilution level of the odorous gas and wherein in each beaker, a single test specimen diffused odorous air, each of the individuals that made up the panel had to identify, in each beaker, which of the test specimens was diffusing the odorous gas, the data from the panel were compiled and the results were calculated with the aid of a table by using the air dilution and odorous gas flow rates of each of the test specimens.