JP4474033B2 - Sewage treatment settling tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sedimentation tank in which a large amount of middle layer water that does not contain solids (precipitates, scum) is overflowed from a waste sedimentation tank in a wastewater treatment process.
[0002]
[Prior art]
Conventionally, a water collecting tank is provided on the outer periphery of the center well, the upper end of a small-diameter water collecting pipe protrudes on the bottom plate of the water collecting tank, the protruding end overflows, and the middle water of the settling tank is collected in the water collecting tank. And the thing which hold | maintains the water level of a precipitation tank at the said protrusion end was developed (No. 6-42725).
[0003]
However, in the above device, the number of small-diameter water collecting pipes is small, so it is difficult to cope with the amount of sewage flowing into the center well, and when the amount of sewage is large, not only the protruding end of the small-diameter water collecting pipe but also the water surface of the entire sedimentation tank is collected. There was a problem that the scum that rises above the ridge and floats flows into the catchment basin, and the scum enters the middle water to be collected.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to keep the water level of the sedimentation tank constant even when the amount of sewage flowing into the center well increases, and to prevent scum from being mixed into the overflowing middle layer water.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a center well extending above and below the water surface at the center of the precipitation tank, a bottom plate protruding along the inner peripheral surface of the precipitation tank, and an annular wall on the inner periphery of the bottom plate. the to protrude upward the catchment groove is formed in an annular shape, juxtaposed a plurality of upper and lower end opening diameter tube at regular intervals to the central portion in the peripheral surface of the annular wall, the upper end opening of the small diameter tube the opening at a position higher than the upper end of the annular wall, Ri the overflow path communicating the intermediate portion and the catchment groove of the small diameter tube name provided in the same level positions in the middle of the annular wall, and the The lower end of the small-diameter pipe is in the middle level of the settling tank, and the water level of the water surface is overflowed from the outside of the settling tank to allow the middle water of the settling tank to overflow from the overflow channel into the catchment groove. The sewage treatment settling tank is held by the sewage supplied to the center well .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
A sewage pipe 8 is inserted into the middle of the tank 1 from the outside of the sedimentation tank 1 and its tip is connected to the middle of an upright and lower end opening upright cylinder (center well 3) disposed in the center of the tank 1. Then, the sewage 8 ′ is supplied into the sedimentation tank 1 through the lower end opening of the center well 3.
[0007]
A water collecting groove 4 is formed in an annular shape along the inner periphery 1 ′ of the settling tank 1. The groove 4 has a bottom plate 4 ′ protruding from the inner peripheral surface of the sedimentation tank 1, and an annular wall 4 ″ protruding upward from the inner peripheral edge of the bottom plate 4 ′ (FIGS. 1 to 3). A drainage channel 9 having a bottom portion at the same level as the upper surface of is opened in the tank wall of the sedimentation tank 1 so that the drainage channel 9 and the water collecting groove 4 are communicated.
[0008]
As shown in FIG. 2, the settling tank 1 is formed in a quadrangular or circular shape, and a plurality of upper and lower end opening small-diameter pipes 5 are arranged in parallel at regular intervals on the inner periphery of the annular wall 4 ″ of the water collecting groove 4. An overflow channel 6 is formed at the same level position in the middle of “and communicated with the middle of the small diameter pipe 5.
[0009]
The opening at the upper end 5 ′ of the small-diameter pipe 5 opens at a position higher than the upper end of the annular wall 4 ″, and the opening at the lower end 5 ″ opens at the middle level of the settling tank 1. Can be incorporated.
[0010]
Solid matter having a high specific gravity in the sewage 7 supplied to the center well 3 from the sewage pipe 8 descends to the bottom of the settling tank 1 as a precipitate 11, and the scum 12 floating on the water surface 2 is removed by the scum schema.
[0011]
The floating scum 12 larger than the inner diameter cannot enter the small-diameter pipe 5 that opens to the middle of the settling tank 1, and the middle layer water 10 rises into the pipe 5, In order to allow the middle layer water 10 to overflow into the water collecting groove 4, the water surface 2 (water level) of the settling tank 1 is determined by the overflow from the overflow channel 6 to the water collecting groove 4.
[0012]
The upper end opening 3 ′ of the center well 3 opens above the water surface 2 (water level) and is supported at substantially the same level as the upper end of the annular wall 4 ″.
[0013]
Even when the amount of sewage from the sewage pipe 8 suddenly increases, the inner peripheral length of the annular wall 4 "is long and a large number of the small diameter pipes 5 are provided. The overflow channel 6 is provided in the middle of the annular wall 4 ″ (FIG. 4), and even if the water surface 2 rises slightly from the overflow channel 6, the upper end of the annular wall 4 ″ can be accommodated. Further, as shown in FIG. 5, the water level overflows from the U-shaped overflow channel 6 until reaching the upper end of the wall 4 ″, and the floating scum 12 flows into the water collecting groove from the upper end of the annular wall 4 ″. There is no fear of flowing into 4. The overflow channel 6 can of course be a tubular structure or a U-shaped structure penetrating the annular wall 4 "as shown in FIGS.
[0014]
【The invention's effect】
Since the present invention is configured as described above, it can be adapted to changes in the amount of sewage supplied into the center well, and there is no risk that the floating scum will flow into the water collecting groove, and a large amount of middle layer water in the settling tank can be collected safely. There is an effect that water can be collected in the water groove.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a sewage treatment sedimentation tank of the present invention.
FIG. 2 is a partially cutaway plan view of FIG. 1;
FIG. 3 is a partially enlarged longitudinal sectional view of FIG. 1;
4 is a partially cutaway front view taken along line 3A-A of FIG.
FIG. 5 is a front view of a U-shaped overflow channel.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Precipitation tank 1 'Inner circumference 2 Water surface 3 Center well 4 Water collecting groove 5 Upper and lower end opening small diameter pipe 5', 5 "Upper and lower end 6 Overflow channel

Claims (1)

A center well over the top and bottom of the water surface is placed in the center of the settling tank,
Along the inner circumferential surface of the precipitation tank projected bottom plate, to project the annular wall upwardly to form a water collecting groove annularly on the inner peripheral edge of the bottom plate, the central portion side in the peripheral surface of the annular wall juxtaposed a plurality of upper and lower end opening diameter tube regular intervals, the upper end opening of the small diameter tube is opened at a position higher than the upper end of the annular wall, communicates the middle and the catchment groove of the small diameter tube overflow path to the Ri name provided in the same level positions in the middle of the annular wall, and the lower end of the small diameter tube is in the middle level of the settling tank, precipitation on the catchment groove from the overflow path A sewage treatment settling tank in which the water level of the water surface is retained by sewage supplied to the center well by a sewage pipe from the outside of the settling tank in order to overflow the middle layer water of the tank.

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