抄録
T-N removal performance was investigated using observed data on rural sewerage facilities with anaerobic and aerobic submerged filters. It was found that probability distribution of T-N in influent and effluent of rural sewerage facilities obeyed normal distribution or logarithmic normal distribution, T-N removal in anaerobic filter tank was assumed to depend primarily on influent T-N concentration, influent of NOx-N/T-N rate, and SS reduction in anaerobic filter tank. Because effluent NOx-N/T-N rate of contact aeration tank also will be determined from hydraulic loading (hydraulic detention time), it is clear that recirculation ratio shall be related to influent NOx-N/T-N rate of anaerobic filter tank. It is suggested that influent NOx-N/T-N rate of anaerobic filter tank may be affected significantly by recirculation ratio so that T-N removal shall be governed from recirculation ratio. It is possible that effluent T-N concentration and influent NOx-N/T-N rate of anaerobic filter tank can be predicted by recirculation ratio and effluent NOx-N/T-N rate from flow equation tank. Consequently, it is important that control of SS and hydraulic detention time is effective to maintain T-N removal efficiency in anaerobic filter tank. T-N removal in contact aeration tank is also influenced by influent T-N and SS reduction.
