| 摘要 |
<p>PURPOSE:To impart denitrifying function without damaging compactness and energy conserving properties by a method wherein a raw water inflow process and a mixing process are continuously or intermittently held to an anaerobic state and an aeration process is continuously or intermittently held to an aerobic state and the water in a tank is recirculated from the lower part of a filter bed to the upper part thereof in the raw water inflow process, the mixing process and the aeration process. CONSTITUTION:Raw water is allowed to flow in a tank from a raw water inflow pipe 2 to perform denitrification, the removal of BOD and the capture of suspended solids (SS) in an anaerobic state for a predetermined time. The inflow of the raw water is stopped while the recirculation of the raw water in the tank is continued to perform mixing by a recirculation stream for a predetermined time and treatment is performed in the anaerobic state. In an aeration process, air is supplied from an air inflow pipe 14 through a perforated pipe 6 to perform the nitrification of ammonia nitrogen in water, the removal of BOD and the capture of SS. Treated water is gathered to a perforated pipe 7 to be discharged out of the tank through a treated water discharge pipe 11 and, at this time, the discharge speed of treated water is kept constant by a flow rate control valve 15.</p> |
