| 摘要 |
<p>PURPOSE:To remove nitrogen without decreasing the BOD treating efficiency by introducing the original water into a waterway through an absolute anaerobic tank, dicharging the treated water to the outside of the system by connecting a settling pond with the discharge port, and introducing the settled sludge into the waterway through the absolute anaerobic tank. CONSTITUTION:The original water 6 introduced into a ditch tank 1 is circulated in the tank and charged into a settling tank 5, and the treated water 8 is discharged to the outside of the system. The sludge is returned to an absolute anaerobic tank 20 as the returned sludge. The anaerobic-aerobic stress is given to the sludge by such circulation as ditch tank 1 settling pond 5 absolute anaerobic tank 20 ditch tank 1. And the phosphorus is biologically removed. The sludge with increased content of phosphorus is discharged to the outside of the system as the excess sludge, and treated separately. In addition an underwater propeller, etc. is necessarily provided in the anaerobic tank 20 to give a current sufficient to prevent the settling of the sludge.</p> |
