| 摘要 |
<p>PURPOSE:To obtain a satisfactorily purified water having a small SS and BOD and efficiently stabilize nitrification of dirty water in order to contrive the improvement of the dirty water treatment by a method wherein a treating tank is provided with an upper fixed layer filled with a three-dimensional net-like granulated solid, a lower fixed layer filled with the granulated solid of any type and two air diffusing members, one located between these two fixed layers and the other located below the lower fixed layer. CONSTITUTION:An organic dirty water supply pipe 2 is provided above a treating tank 1. The treating tank 1 comprises a fixed layer A which receives therein the downward flow of raw water 14 fed from the dirty water supply pipe 2 and which is formed above a water- permeable porous member 3 provided at the middle part of the treating tank 1 and is filled with a three-dimensional net-like granulated filter material; an air diffusing member 4 provided below the fixed layer A for supplying there-through to the fixed layer A an oxygen-containing gas required for the biological treatment thereof; a fixed layer B filled with the granulated filter material of any type provided below the porous member 3; an air diffusing member 5 provided below the fixed layer B for supplying therethrough an oxygen-containing gas to the fixed layer B for biological treatment thereof; and a purified water outlet opening 7 provided at the lower part of the treating tank 1, for discharging the purified water through a purified water outlet pipe 8 to outside.</p> |
