においの強度と濃度の間の相関に関する考察(第13報) : 混合臭の臭気濃度の算出

Abstract

Being informed of the material concentrations of the components of a compound odor, we have calculated its odor concentration; Eq. (3) in text was applied to the cases where the odor-carrying bags are in themselves perfectly odorless and Eq. (5) to those where the bags are indistinctly odorous. The results of calculation are shown in Tables 1-5,together with the observed ones. The samples of odor were obtained, periodically, at several sites outside a kraft-paper mill in recent few years and further, were gathered from the odor control systems of a night-soil treatment works and a sewage disposal plant under their efficiency tests; the components measured were hydrogen sulfide, methyl mercaptane, dimethyl sulfide and dimethyl disulfide, and, in additition, ammonia. The odor concentration was determined by a triangle test, whereby an odor-carrying bag shall be olfactorily discriminated from the other two odor-not-carrying ones. It is seen from the tables that there is a good agreement between the calculated and observed values of odor concentration, if calculation has been made by utilizing Eq. (5) with a parameter, Δ, ranging from 0.1 to 2.0; the finding might permit us to arrive at the conclusion that, notwithstanding a pre-treatment such as air-wash of the bag by odor-free air, it is almost impossible to turn an odorous bag to an odorless one. Mention was added of (1) the broadness in the odor intensity observed olfactorily and (2) the approximation prepared for deriving Eq. (5).