Optimization of a sequencing batch reactor with the application of the Internet of Things

Abstract

Internet of Things (IoT) technology was applied to the operation of the sequencing batch reactor (SBR) process to increase nitrogen removal and tackle the disturbances caused by the inflow fluctuations. To cope flexibly with the fluctuations in the inflow load, the time required for settling and discharging (TRSD) was reduced by inventing an automatic mechanical decanter, operated by monitoring the height of the sludge blanket layer and the concentration of suspended solid (SS) in the supernatant. The average TRSD of the automatic mechanical decanter was 1 hr, which was reduced by 27–59% compared to the conventional SBR processes treating domestic wastewater. Increasing the bio-reaction time with reduced TRSD allows improved performance while maintaining the overall cycle time of the SBR processes. Nitrogen removal was enhanced by feeding the influent in two steps in an 8:2 ratio while monitoring nitrogen ions in the bioreactor. The total nitrogen (T-N) removal of the step-feed modes was 92–93%, while that of the single-feed modes was 82–88%. Although the average time required for the bio-reaction steps increased by 51 min in the step-feed mode under the same temperature condition (13–16 °C), the total cycle time of the SBR process did not exceed 6 hr/cycle due to the reduced TRSD. By applying IoT technology, reliable operation of the SBR and improved T-N removal were achieved.