Abstract
The residents' odor complaint is steadily increasing by odor causing from sewage system. A current drainage facilities and septic tank are included in the individual sewerage according to Sewerage Act. However, definitions and legal standards of drainage tank are insufficient. In addition, specifications and maintenance standards related to structure and size are not established. In this research, effect of drainage tank in individual sewage facilities on the odor occurrence was studied and the concentrations of $H_2S$ and composite odor were measured. From the measurements, the concentration of $H_2S$ and composite odor were 1 ppm ~ 5 ppm and 1.04 OU ~ 4.05 OU, respectively, before pump operation. Also, the concentration of $H_2S$ and composite odor were 5 ppm ~ 33 ppm and 5.10 OU ~ 35.04 OU, respectively, after pump operation. The concentration of SS in the effluent from drainage tank was ranged from 840 mg/L to 1,980 mg/L. These high concentration of SS seemed to be the major source of foul smell when high concentrated suspended solids in the public sewerage system were decomposed and then emitted. In this research, correlation coefficient ($R^2$) between $H_2S$ and composite odor before and after pumping were 0.925 and 0.918, respectively.