| Abstract |
| The settling of a sequencing batch reactor (SBR) is a very important process to polish the effluent water Quality and time-consuming process compared to the other process cycle to remove nutrient and carbon compounds. To detect the completion point of settling, an automatic detection and control algorithm for a settling time of SBR was developed using Oxidation-Reduction Potential (ORP) profile. To extract the relationship between the ORP profiles and sludge settling, various ORP profiles and Sludge Blanket Height (SBH) were collected at three range of SVI(20-50, 50-100, over 100) and four MLSS concentrations (2000, 4000. 6000, 8000 mg/L) for each SVI categories. With collected profiles, it was found that the completion of sludge settling and ORP profile`s stabilization point have a proportional relationship. Based on this observational result. the Moving Least Squre Method (MLSM) for the ORP profile was used to detect ORP profile`s stabilization point. However, for a special case of bulking sludge, the detected settling completion point and automatic effluent decanting has possibility of sludge wash-out. To deal with this problem, the control algorithm was modified by referring DO value to detect existence of sludge at the high level of the reactor. The developed algorithm was verified through the settling test and MLSS measurement of the supernatant for the bulking sludge and showed its good detection performance. |
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| Key Words |
| detection, dissolved oxygen (DO), Moving Least Square Method (MLSM), Oxidation-Reduction Potential(ORP), Sequencing batch reactor(SBR), Sludge settling |
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