| 摘要 |
<p>PURPOSE: To propose an aerobic treatment method for organic drainage which can reduce the volume of sludge, prevents the deterioration of sludge activity caused by ozone-treated sludge, can keep high sludge activity for biological decomposition, and thereby can obtain high quality of treated water by preventing the deterioration of quality of treated water. CONSTITUTION: In a biological decomposition method in which organic drainage is introduced into an aeration tank 11 to be subjected to aerobic biological treatment in the presence of biological sludge, mixed liquid in the tank 11 is separated into solid and liquid by a solid-liquid separation tank 12, the separated liquid is discharged as treated liquid, part of separated sludge is returned to the tank 11, and part of separated sludge is ozone-treated in an ozone treatment tank 21 and returned to the tank 11, the volume of ozone-treated sludge is made constant to correspond to a sludge volume reduction ratio, and the amount of returned ozone-treated sludge to that of returned sludge in the sludge return part of the aeration tank is arranged to be 1/2 or less.</p> |
