Oxygen was consumed during the nitrification reactions in the reactor, but when the
nitrification reactions stop, respiration was in an endogenous state. It is possible to
make decisions based on the respiration analysis. In this research, a nitrification
monitoring kit based on the oxygen uptake rate of SBR was developed and applied at
a pilot scale plant to control the aeration system. As a result, process capacity was
increased by 150% and electricity power was decreased by 44.8% by replacing the
operation and control process. The OUR-N computing change rate of microbial
respiration can reduce the processing time and aeration energy depending on the raw
wastewater loading.