| 摘要 |
<p>PURPOSE:To provide the sewage septic tank which stably produces high-degree treated water, minimizes waste water of washing and is small in size and high in performance by housing porous granular materials into a biological filtration layer, dividing this filtration bed to two blocks, upper and lower, with perforated members and segmenting the upper part as an aerobic reaction zone and the lower part as a filtration zone. CONSTITUTION:The biological filtration layer is formed by housing the granular carriers into the biological filtration tank 4 of the sewage septic tank constituted by integrating an anaerobic filter bed tank, denitrification tank, biological filtration tank 4, treated water tank 21 and disinfection tank. The biological filtration layer is divided by the perforated members 16, 18 to the two blocks, upper and lower. The reaction zone mainly consisting of aerobic biological decomposition is constituted in the upper block and the filtration zone mainly consisting of physical filtration is constituted in the lower block. Water 23 to be treated is introduced from the upper part into the biological filtration tank 4 and is treated by coming into counter current contact with the air from the lower part of the upper block. The washing of the biological filtration tank 4 is executed by introducing the treated water as washing water 26 from the bottom of the tank and by the air from the bottom of the lower block. The waste water is discharged from a drain pipe 17 in the boundary part between the upper and lower blocks and IS transferred to the anaerobic filter bed tank.</p> |
