At the time of the end of 2013, public sewage treatment facilities running nationwide facility capacity to over the 500 m³/day is 569 places at 25,085,810 m³/day, less than 500 m³/day facility capacity to 3,205 places is 244,592 m³/day. This is increased by about 2% annually in sewer diffusion rate 78.8% from 2003 to 2013 increased to 92.1%, but due to factors such as an increase in population. Also, every year changes in the inflow rate and the inflow sewage of concentration of sewage treatment facilities, has increased continuously. The concentration of organic matter in the sewage thus generated, which is removed by sewage treatment process, the most important process in the second process is a biological process. Most biological processes, maintaining DO, pH, and the environment of operation by a temperature sensor. But if you have these sensors to the original, there is a disadvantage that it is impossible to monitor the state of the microorganisms directly. And, therefore, in this study, we tried to study the possibility by direct measurement method the state of the microorganisms of activated sludge was used intermittently investigation and deviation capture of NADH of the light source of the biological reaction tank. In this study, measured is installed a detector capable deviation capture detection by a light source is irradiated to the fluorescence due to the reaction of NADH in microorganisms in light source unit and 460 nm which can be intermittently irradiated with UV at 340 nm, and devices, profile is made to be composed of a passage for receiving the fluorescence emitted microorganisms by irradiation with UV light microorganisms size diameter 200 mm, length 740 mm. Biological reactor of interest, and the activated sludge biological reaction tank of Gyeonggi A City sewage treatment plant to the subject, measurement points, was carried out in the total of four locations. The sensor was calibrated in the same conditions as zero state laboratory, this time when the NAD based on the water 0.2 m point current (A) is 50 mA, 100 mA, 200 mA, respectively 26, 48, 84.5 has been measured in the (intensity value). This is according to the increase in current value. Intensity also proportionally increased, is determined as indicating a direct electrical reception may show the ease of measurement. Also, salvaged and re-invasion enemy repeatedly re-dipping after, shows the Intensity value of 84.1 at 200 mA, it was found that the reproducibility is good. The results were tested using an actual immersion light measuring device using the intermittent investigation and variance capture method from bioreactor wastewater treatment plants in operation, changes in the value of the change in star Intensity of current, as the load is high, higher and the current value increases, the proportional is increased it is determined that the reproducibility is good, and those entering least a light source and the detection consumable parts rain due to the previous year and maintain than investigation and detection methods continuous light source.

• Seong-Min Hong(R&D Center in Aquatech Co.)
• Han-Lae Kim(R&D Center in Aquatech Co.)
• Quan-Woo Park(R&D Center in Aquatech Co.)