FEASIBILITY OF UNMANNED SYSTEM APPLICATION FOR BIOLOGICAL NITRIFICATION/DENITRIFICATION PROCESSES IN INDUSTRIAL WASTEWATER TREATMENT

摘要

The biological nitrogen removal process is a commercial and economically viable solution for removal of nitrogen from the industrial wastewater. Several types of reactors could be used for the conventional biological nitrogen removal system with suspended biomass, such as A/O processes, membrane bioreactor (MBR) and sequencing batch reactors (SBRs). Because of the advantages of the operational flexibility and low initial cost, the SBR was selected as the bioreactor in this study. A 6-1 laboratory-scale bioreactor has been operated as SBR system for ABS wastewater treatment. Oxidation reduction potential (ORP), pH and dissolved oxygen (DO) concentration were measured and monitored by on-line sensors every minute and these data also was send to computer controller for establishing an unmanned control system. According to these experimental results, ORP has dropped sharply from around -130 mV to below -250 mV and the slope of ORP curve was over then -4 mV/min in the end of the denitrification. In the end point of the nitrification, DO concentration increased from 2 mg O_2/l to above 4 mg O_2/l at a rate in excess of 0.05 mg O_2/l - min and ORP also increased from around 100 mV to above 200 mV at a rate in excess of 4 mV/min. Finally, an unmanned control system was built and applied to this SBR system. With this system, it was possible to reduce the operation time of the SBR from 19.5 to about 15-16.5 h under the same removal efficiency. Therefore, the feasibility of unmanned system application for SBR system was confirmed in this study.