Study On Preparation Of The Novel Rotating Drum Biological Contactor And Performance Of Biological Nitrogen Removal

A novel Rotating Drum Biological Contactor(RDBC) was developed, which combined the advantages of Rotating Biological Contactors(RBC) with moving bed biofilm reactors’ in this study. The packing was rotated by the rotation drum to speed up the biofilm updating rate and oxygen transfer efficiency, respectively. Pollutions were degraded efficiently. Oxygen transfer characteristics were investigated and the synthetic sewage wastewater was treated to show the performance of RDBC. The effects of immersion level and rotating speed on oxygen transfer coefficient and power efficiency was studied. The performance of RDBC in the process of A/O and Simultaneous Nitrification and Denitrification(SND) was investigated for biological nitrogen removal, respectively. The operating parameters were optimized in each reactor. The main conclusions were as followings:1) Suspended packing was chosen as the optimized packing for the RDBC. Anaerobic, anoxic and aerobic operating modes can be achieved by adjusting the drum immersion level and rotating speed. Volume oxygen transfer coefficient(KLa) and power efficiency(Ep) can reach 25.87 1/h and 228.62 g/k Wh, respectively. The drum rotating speed was in direct proportion to the KLa in constant immersion level, and the drum immersion level was in inverse proportion to the KLa in constant rotating speed, respectively.2) Synthetic domestic sewage was treated with A/O process. The results showed that the optimal operating conditions were immersion level 100%, rotating speed 4 r/min, and DO 0.2 mg/L in anoxic tank, respectively, and immersion level 2/3, rotating speed 9 r/min, and DO 3.5 mg/L in aerobic tank, respectively. In above conditions, when the influent average COD, NH4+-N, TN was, total inflow, and recirculation ratio was 367.5 mg/L, 36.3 mg/L, 36.3 mg/L, 10 L/h(HRT=12 h), and 3:1, respectively, the effluent COD concentration, NH4+-N concentration, and TN concentration can reached 43.6 mg/L, 4.5 mg/L and 12.9 mg/L, respectively, which can meet the first level A discharge standards in China(GB18918-2002). When the recirculation ratio increased to 2:1 at total water 12 L/h, TN removal efficiency could be increased remarkably, in which effluent TN concentration was 9.8 mg/L and TN removal efficiency was 73.26%.3) Synthetic domestic sewage was treated with SND process. Biofilm nitrification and denitrification rate can be coordinated by adjusting drum immersion level and rotating speed to enhance TN removal efficiency. When the total inflow, immersion level, rotating speed, DO, the influent average COD concentration, NH4+-N concentration, TN concentration, organic loading, and ammonia loading was 6 L/h(HRT = 8 h), 2/3, 6 r/min, 1.0 mg/L, 393.8 mg/L, 38.0 mg/L, 38.0 mg/L, 1.18 kg COD/(m3·d), and 0.11 kg COD/(m3·d), respectively, the effluent COD concentration, NH4+-N concentration, TN removal efficiency, average TN removal efficiency, and SND rate was 27.14 mg/L, 2.0 mg/L, 58.55%~83.94%, 67.34%, and 68.27%, respectively, which can meet the first level A discharge standards in China(GB18918-2002).