NOVELTY - Microorganism degradation septic tank comprises horizontal strip box (1) with elliptic cross section, and sewage inlet (3) and purified water outlet (15) which are connected to two ends of the box. The box is separated into A, B, C, D rooms by three clapboards (4), where every room is provided with a top window (7). The bottom of A, B, C rooms is taper, and the bottom of D room is flat. The taper part is provided with a magnetic valve (16). Strip deposition-removing devices (2), which are hand-operated scraping conveyers, are provided on inner wall and two ends at the bottom of the box.    USE - Septic tank for degradation of microorganism.    ADVANTAGE - The septic tank adopts the combination of microorganism purification, permeation and sterilization, thus realizing high purifying efficiency and low cost.    DETAILED DESCRIPTION - A microorganism degradation septic tank comprises a horizontal strip box (1) with elliptic cross section, and a sewage inlet (3) and a purified water outlet (15) which are connected to two ends of the box. The box is separated into A, B, C, D rooms by three clapboards (4), where every room is provided with a top window (7). The bottom of the A, B, C rooms is taper, and the bottom of the D room is flat. The taper part is provided with a magnetic valve (16). Strip deposition-removing devices (2) are provided on longitudinal inner wall and two ends at the bottom of the box. The magnetic valve is connected to wall (2.1) of strip deposition-removing devices. The A room is close to the B room. Two rooms are connected by branch pipe of bent three-way pipe (8). The middle of B room is separated into upper and lower chambers by parallel filter layer (9) and carbon bed (10). The vertical bent three-way pipe penetrates through the filter layer and carbon bed from top to bottom to the lower chamber. The C room is located between the B room and D room and is connected to the neighbor room by a three-way pipe (11) and a bent pipe (13). The middle of the C room is separated into upper and lower chambers by parallel double-layer microorganism absorbing beds (12). The three-way pipe penetrates through the microorganism absorbing bed from top to bottom to the lower chamber. A suspended fiber curtain (14) is provided in the D room.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic view of the microorganism degradation septic tank.    Horizontal strip box (1)    Strip deposition-removing device (2)    Wall (2.1)    Sewage inlet (3)    Clapboard (4)    Top window (7)    Three-way pipe (8)    Filter layer (9)    Carbon bed (10)    Three-way pipe (11)    Microorganism absorbing bed (12)    Bent pipe (13)    Suspended fiber curtain (14)    Purified water outlet (15)    Magnetic valve (16)