TWO BED JUXTAPOSITION TYPE AEROBIC FILTER BED TANK, SEPTIC TANK AND OPERATION METHOD THEREOF

PROBLEM TO BE SOLVED: To provide a aerobic filter bed tank, a septic tank and an operation method thereof which gives treated water of good quality and contributes energy-saving. SOLUTION: In this aerobic filter bed tank, a biological reaction vessel 13 having a biological reaction bed 5 and a filter vessel 14 having a filter bed 6 are juxtaposed across a partition wall 15 in this order from the upstream side, a diffusing member 9 for reaction is disposed on the lower part or the lower side of the biological reaction bed 5 and a diffusing member 10 for washing is disposed on the lower part or the lower side of the filter bed 6. Therein, further, a space part 7 is disposed on the lower side of the filter bed 6 and a suction port of a transfer pump 11 is disposed on the space part 7 or in the vicinity thereof. The quality of the treated water is made excellent thereby. If only the discharge speed of waste washing water at washing is slightly larger than the natural flow speed, it is satisfactory and, therefore, contributes the energy-sawing. This aerobic filter bed tank can be attached to a conventional single manure disposal purifying tank and allows the manure disposal tank to be transferred to a combined treatment septic tank.