This study was conducted to investigate anoxic-RBC (rotating biological contactor) and its application in advanced municipal wastewater treatment process to remove biologically organics and ammonia nitrogen. Effluent COD and nitrogen concentration increased as the increase of volumetric loading rate. But, the concentration changes of NO2--N and NO3--N were little, as compared to COD and NH4+-N.
When the volumetric loading rate increased, COD removal efficiency and nitrification appeared very high as 96.7～98.8% and 92.5～98.8%, respectively. However, denitrification rate decreased to 76.2～88.0%. These results showed that the change of volumetric loading rate affected to the denitrification rate more than COD removal efficiency or nitrification rate.
The surface loading rates applied to RBC were 0.13～6.01g COD/㎡-day and 0.312～1.677g NH4+-N/㎡-day and they were increased as the increase of volumetric loading rate. However, the nitrification rate showed higher than 90%.
The thickness of the biofilm in RBC was 0.130～0.141㎜ and the density of biofilm was 79.62～83.78㎎/㎤. They were increased as surface loading rate increased. From batch kinetic tests, the kmaxH and kmaxN were obtained as 1.586 g C/g VSS-day, and 0.276 g N/g VSS-day, respectively.
Kinetic constants of denitrifer in anoxic reactor, Y, ke, Ks, and k were 0.678 ㎎ VSS/㎎ N, 0.0032 day-1, 29.0 ㎎ N/ℓ, and 0.108 day-1, respectively. P and Ks values of nitrification and organics removal in RBC were 0.556 g N/㎡-day and 18.71 g COD/㎡-day, respectively.

• 최명섭(부경대학교 토목공학과) | Myung-Sub Choi
• 손인식(부경대학교 토목공학과) | In-Shik Shon Corresponding Author