USBF Performance in Nitrogen Removal and Determination of Reactor Optimum Conditions

In this study the efficiency of USBF
in biological nitrogen removal for achieving the optimum nitrogen concentration and COD/N ratio according to the maximum system removal efficiency was determined. The synthetic wastewater used in this research was composed of glucose and urea with COD/N ratio of around 10 with nitrogen concentrations of 10, 30, 50, 75, 100 and 150 mg/L and with COD/N ratio of about 6.67, 5 and 4 with nitrogen concentrations of 75, 100 and 125 mg/L. The initial experimental results have shown that by increase in nitrogen concentration with COD/N of 10, the nitrogen removal efficiency was increased in such a way that in concentrations of 10, 30, 50 mg/L after reaching the stable condition, the mean nitrogen removal efficiency was reached to about 89, 91 and 92.2 percent respectively. But as concentration increased to 75, 100, 150 mg/L, the mean nitrogen removal efficiency was decreased to 85.5, 82.4, 76.3 percent respectively. Then, with the COD/N ratio of 4, 5 and 6.67 and increased in concentration to 75, 100 and 125 mg/L, the percent nitrogen removal efficiency reached to 93.3, 87.4 and 82 respectively. Finally, COD and nitrogen concentrationof 500 and 75 mg/L (COD/N ratio of 6.67) were selected as optimum conditions for pilot-scale USBF process.