Because sensing odor varies depending on each person, even if the odor is released in line with the legal emission permission concentration levels, it can still become a social issue if a civil complaint is made. The purpose of this research is to study the possibility of putting Mn-Cu metallic oxide catalysts into practical use to economically eliminate acetaldehyde which produces a odor in the industrial process. An optimal operating parameter to eliminate acetaldehyde was deduced through a performance evaluation in the research laboratory and the performance was verified by applying the parameter into an actual facility as an on-the-site experiment through a Scale-up of pilot size. The operating temperature of the metallic oxide catalysts researched so far was at the minimum close to $220^{circ}C$, and the $220^{circ}C$ elimination efficiency was 50% or below. However, having experimented by using a Mn-Cu metallic oxide catalyst in this research, optimum elimination efficiency showed when space velocity (GHSV) was equal to or below 6,000 $hr^{-1}$. The average elimination efficiency was 61.2% when the catalyst controlling temperature was $120^{circ}C$, 93.3% when the catalyst controlling temperature was $160^{circ}C$, and 94.9% when catalyst controlling temperature was $180^{circ}C$, thereby reflecting high elimination efficiency. The specific surface area of the catalyst was $200m^2/g$ before use, however, was reduced to $47.162m^2/g$ after 24 months and therefore showed that despite the decrease in specific surface area as time passed, there was no significant influence on the performance. Having operated Mn-Cu metallic oxide catalyst systems for at least two years on a site where there was no inflow of toxins like sulfur compounds and acidic gases, we were able to confirm that elimination efficiency of at least 90% was maintained.