Abstract
In this study, a method for estimating degradation characteristics of organic matter and nitrification conditions in the sequencing batch reactor (SBR) was investigated by measuring oxygen uptake rate (OUR) . The experiments were carried out by changing the ratio of the influent fed in the SBR. The influent used for the experiment was collected from a separated-type sewage-treatment plant, where mainly domestic wastewater has been treated. Two kinds of OURs: total oxygen uptake rate (TOUR) and carbonaceous oxygen uptake rate (COUR) were measured simultaneously. The COUR was measured in the presence of allylthiourea as a nitrification inhibitor. Nitrogenous oxygen uptake rate (NOUR) was calculated by subtracting COUR from TOUR. It is suggested that the measurement of COUR could be used to estimate the concentration of TOC in the supernatant of the mixed liquor in the SBR. The application of NOUR was found to be very effective for examining the presence of NH4-N in the effluent. Thus the degradation characteristics of organic matter and the nitrification conditions in the SBR could be analyzed by measuring both COUR and NOUR.
