In order to determine the location of average concentration and distribution status of dissolved oxygen in the rectangular aeration tank of the sewage treatment plant was analyzed and the difference of dissolved oxygen concentration was remarkable at each location. Compared with the computational fluid dynamics analysis, it was found that the results were consistent with the measurement results by showing the difference of dissolved oxygen concentration between the locations. Based on the measured data, the representative location of dissolved oxygen in aeration tank was selected by using statistical analysis method and the representative location was expressed in three-dimensional coordinates(LWH : 25%, 50%, 33%) from flow direction and left wall. Also the difference between the dissolved oxygen concentration at the actual measurement location and the average concentration value of the entire aeration tank was founded, and the equations for calibrating the automatic measurement data considering the actual measurement location were calculated.

This study was performed to investigate the contamination characteristics of water in the scrubber with the aim of stably maintaining the scrubber, and to comprehend the removal characteristics of sulfur compounds, which are odorous substances, when microbubbles were supplied to the circulation water tank of a scrubber. The results of our analysis found that 63 kinds of gas compounds were detected from the scrubber, and thus it could be determined that Sulfur compounds, Ammonia (base compounds), Aldehyde compounds, and Pyrazine compounds were generated from the process for the production of sesame oil. About 93% of ammonia was removed in the scrubber; however, it was hard to remove Sulfur compounds, Aldehyde compounds and Pyrazine compounds using the scrubber. The efficiency of hydrogen sulfide, methylmercaptan and dimethydisulfide removal using only water in the scrubber was 79.8%, 79.7%, and 81.0%, respectively. However, when microbubbles were supplied to the scrubber, the removal efficiency for each was 83.7%, 91.1%, and 96.1%, respectively. Therefore, it was confirmed that the efficiency of sulfur compound removal was improved by supplying microbubbles to the circulation water tank of the scrubber. In addition, the amount of removal that could be achieved by using microbubbles was 1.05- 1.19 times higher than using only water. In terms of supplying microbubbles, it was confirmed that the saturation time required to absorb odorous gases was about 2.8 times longer than the time without microbubbles because the OH radicals generated when the microbubbles are shrinking partly oxidized organic matter. When there was no chemical in the circulation water tank, the conductivity and CODCr concentration were highly correlated. Therefore the system, which can replace circulation water by using real-time conductivity data, can be considered to be applicable.