JP4359172B2 - Inclined plate and sewage storage tank - Google Patents

Description

The present invention relates to a bottom surface of a storage tank in which diverted sewage or combined sewage (hereinafter referred to as sewage or the like) is temporarily stored, for example, a flow control basin such as sewage, a reservoir such as sewage (hereinafter referred to as a storage tank or the like). And an inclined plate that makes it difficult for sludge and the like to remain on the bottom surface of the storage tank or the like, and a storage tank that does not easily leave sludge or the like.

Conventionally, in a storage tank or the like for temporarily storing sewage or the like, sludge or the like contained in sewage or the like is deposited on the bottom surface thereof as shown in FIG. 5, for example. The accumulated sludge and the like remain on the bottom surface of the storage tank and the like even after the stored sewage is discharged from the storage tank and the like, odor is generated, and maintenance such as regular cleaning is necessary.

In order to prevent this, normally, the bottom surface of the storage tank or the like is an inclined surface having a gradient of about 2/100 to 5/100, and the storage tank has a structure in which the sludge that sinks is guided to the deepest part of the inclined surface. Things were going on. Sludge that settles on the bottom surface, is guided to the deepest part along the slope, and accumulates and remains in the deepest part even when sewage is discharged, is generally discharged and removed by a sludge pump. And the removed sludge and the like are treated separately (for example, see Non- Patent Document 1).

Conventionally, in these storage tanks having an inclined bottom surface, the inclined bottom surface is a flat surface, and in order to smoothly move the inclined surface toward the deepest part of the sludge that has settled, the inclination angle of the inclined surface is set. It needs to be bigger. If the inclined bottom surface has a large inclination angle, the difference in height between the high and low inclination sides becomes large, making it impractical for a large-capacity storage tank. There is also a risk of falling. Therefore, the basin-bottom tank is usually small in inclination angle or low incline toward the center of the bottom surface.

However, if the tilt angle is reduced, sludge etc. will not move smoothly, and settled sludge etc. will not be guided to the deepest part, but will partially accumulate and remain on the bottom surface, causing odor and floating scum. There is a problem that it becomes.
“Sewerage Facility Planning and Design Guidelines and Explanations, Part 1, 2001”, Japan Sewerage Association, May 24, 2001, p. 446-p. 450

The problem to be solved by the invention is to solve the problems in the conventional storage tank having an inclined surface, and even if the inclination angle of the bottom surface is small, sludge etc. hardly remain on the bottom surface after discharging sewage etc. In order to make it a storage tank etc., it carried out for the purpose of providing an inclined plate provided on the bottom surface of the storage tank.

An inclined plate (Invention 1) according to claim 1 of the present invention for solving the above-mentioned problem is an inclined plate made of a synthetic resin disposed on the bottom surface of a storage tank in which sewage is temporarily stored. A plurality of concave grooves are formed on the upper surface along the inclination direction of the inclined plate, and the cross-sectional shape of the concave groove in a direction perpendicular to the inclined direction of the inclined plate is arranged in parallel in a zigzag shape having substantially continuous triangles. The direction is inclined at the same angle as the inclined plate.

The sewage storage tank (invention 2) according to claim 2 is a storage tank in which sewage is temporarily stored, and the bottom surface of the storage tank has a slope with a high sewage inflow direction and a low sewage discharge direction. Thus, the inclined plate of the invention 1 is arranged.

The inclined plate according to the first aspect of the present invention is used to temporarily store sewage or the like in a storage tank, and when the stored sewage or the like is discharged for transfer to the next step, it is included in the sewage or the like and is deposited on the bottom surface of the storage tank. When it is necessary to make the remaining sludge etc. as small as possible, it is placed on the bottom of the storage tank and used.

The storage tank may be a normal (steel) concrete cast-in-place, a tank assembled with a precast concrete member such as a box culvert, or a tank or pipe made of steel plate or synthetic resin. Any tank placed on the ground may be used.

The inclination direction of the inclined plate is preferably set to be low along the flow direction of sewage or the like so that the settled sludge and the like are smoothly moved to the lower inclination side. Therefore, it is preferable that the inflow position of sewage or the like to the storage tank is on the high position side of the inclined plate, and the discharge position of the stored sewage or the like is on the deepest side of the inclined plate.

Normally, when the container is a storage tank or the like, drainage of sewage or the like is performed by installing a suction port for sewage or the like at the deepest part of the tank and using this pump. In the case of a natural flow such as a flow path, it is only necessary to flow out from the lowest part of the inclined plate to the next process. If it carries out like this, the sludge etc. which have accumulated in the tank deepest part vicinity will become easy to be discharged | emitted from a storage tank etc. along the flow of sewage.

A plurality of concave grooves are arranged in parallel on the upper surface of the inclined plate along the inclination direction of the inclined plate, and the valley direction of the concave groove is inclined at the same angle as the inclined plate. Since the total area of the bottom surface of the storage tank is increased by the concave groove, the flow of sewage generated when draining sewage from the storage tank is faster than when the bottom surface is a flat plate. Accordingly, sludge and the like accumulated in the concave grooves are surely discharged from the storage tank or the like along the flow of sewage generated when discharging the sewage from the storage tank.

The inclined plate is provided with a groove on the upper surface and is disposed on the bottom surface of the storage tank. Sludge and the like are collected in the groove and move along the inclination along the flow of sewage or the like. Therefore, the plate material (hereinafter referred to as the groove plate) constituting the inclined plate, that is, the groove is not particularly limited as long as it is a surface that is corrosion resistant to sewage and the like and sludge and the like are easy to move. Thermoplastic resins such as vinyl chloride resin, polyethylene, polypropylene, and polyester; Thermosetting resins such as urethane resin and epoxy resin; Fiber reinforced resins obtained by fiber-reinforced thermoplastic resins and thermosetting resins; Thermoplastic resins fiber reinforced foamed resins such as foamed thermosetting resin was fiber reinforced and the like. These materials are preferably subjected to sludge adhesion prevention treatment by polishing the surface as necessary, or providing a silicon resin layer, a fluororesin layer or a bactericidal agent layer.

For example, the surface roughness (in accordance with JIS B0601) of the inclined plate is preferably Rmax ≦ 50 im. Instead of defining the surface roughness, the surface tension of the inclined plate is set to 10 to 30 dyn / cm (in accordance with JIS K6768). ) It may be set to a level.

The length of the concave groove is substantially the same as the length of the inclined bottom surface in the flow direction of the sewage in the storage tank and is continuous. However, considering that a person stands on the bottom surface of the storage tank or the like at the time of maintenance, the concave shape may not be provided on the entire surface of the inclined plate, and a part of the concave shape may be left as it is. In this case, the groove may be discontinuous.

When increasing the inclination angle of the inclined plate, if the inclination is only in one direction, the difference in height between the upstream side and the downstream side will increase, so the center of the tank should be the deepest part according to the size of the storage tank. Alternatively, the central portion may be the highest so that sludge and the like are collected on both sides of the tank. At this time, the discharge position of sewage or the like is the deepest part, and may be at the center of the tank or at two locations on both sides of the tank.

In the first aspect of the present invention, the concave groove has a zigzag shape in which the cross-sectional shape in the direction perpendicular to the inclined direction of the inclined plate is a substantially continuous triangle. Therefore, the sludge that settles first hits the inclined surface of the groove and moves in a direction perpendicular to the flow direction of the sewage and is collected in the trough of the groove, and the collected sludge is inclined to the trough by the accumulated weight. Along the lower side of the ramp. At this time, since the lower side of the inclined plate is in the same direction as the flow direction of sewage or the like, the movement of the sludge is accelerated by the sewage flow and is accelerated.

The length of the groove plate in the valley direction, that is, the width of the groove plate is about 100 mm to 500 mm, and is relatively short, so that sludge and the like quickly move toward the groove valley. Since the inclination direction of the troughs of the grooves is lowered along the flow direction of sewage and the like, the sludge and the like collected in the grooves is quickly moved to the lower inclination along the flow of sewage and the like.

The inclination angle of the inclined plate is 2 degrees to 20 degrees. This angle is set to be gentler than the conventional case where the inclination angle of the storage tank having the inclined bottom surface is about 10 to 30 degrees. On the other hand, the inclination angle of the groove plate in the direction perpendicular to the inclination direction of the inclined plate is 10 to 45 degrees from the horizontal direction.

Accordingly, the bottom area of the storage tank is increased as compared with the case of the bottom surface of a flat plate because the bottom surface has a zigzag surface. Therefore, in the troughs of the triangular grooves, the flow rate of sewage or the like becomes faster than when the bottom surface remains flat, and the accumulated sludge becomes easier to move. The cross-sectional shape of the groove may be a smooth curved shape such as a concave shape other than a triangle.

In this way, even if the inclination angle of the inclined surface is gentle, sludge collected in the troughs of the groove is promptly directed to the deepest part of the inclined plate along the flow of sewage when discharging the sewage. Will be moved. For example, if the inclination angle of the groove inclined surface is set to 30 degrees and the inclination angle of the inclined plate is set to 10 degrees, the sludge and the like can be moved in the same manner as in the case where the inclination angle of the flat inclined plate without grooves is 20 degrees.

The sewage storage tank of the invention 2 is a storage tank having a bottom surface with a flat surface, and an inclined plate having a concave groove on the upper surface on the bottom surface, the inclination of the sewage inflow portion is high and the discharge of sewage It arrange | positions so that a part direction may become low.

The inflow position of sewage or the like to the storage tank is the high position side of the inclined plate, and the discharged position of the stored sewage or the like is the deepest side of the inclined plate. In addition, the inclination direction of the inclined plate is set to a low inclination along the flow direction of sewage or the like in order to smoothly move the sludge that has settled to the lower inclination side.

The bottom area of the storage tank is increased as compared with the case of a flat bottom surface because the bottom surface has a zigzag surface. Therefore, in the troughs of the triangular grooves, the flow rate of sewage or the like becomes faster than when the bottom surface remains flat, and the sludge accumulated in the grooves easily moves. The cross-sectional shape of the groove may be a smooth curved shape such as a waveform other than the triangle.

The inclined plate is fixed to the bottom surface of the storage tank with a dedicated fixing jig. For example, if the concave groove is a zigzag shape with a triangular cross-section, the groove plate is fixed with the peak-specific fixture and the valley-specific fixture so that the groove plate retains the zigzag shape, and the butted portion between adjacent groove plates is jointed Seal with a stopper.

Since the fiber reinforced rigid urethane resin foam plate needs to have strength to withstand water pressure and its own buoyancy, its thickness is usually about 10 mm to 30 mm. In addition, this foam covers the surface that comes into contact with sewage with anti-corrosion and wear-resistant or low surface tension coatings such as epoxy resin and urethane resin that have excellent corrosion resistance and smoothness, and can move more sludge and the like. It is desirable to make it easy and to have a long life. In addition, when using as a concrete formwork board, the surface which contacts concrete may be made into a rough surface without processing, and an anchor effect may be raised.

The inclined plate of the present invention is made of synthetic resin, and a plurality of concave grooves are formed on the upper surface of the inclined plate along the inclined direction of the inclined plate, and the sectional shape of the concave groove in the direction perpendicular to the inclined plate inclined direction is substantially the same. Triangles are arranged in a continuous zigzag shape, and the valley direction of the concave grooves is inclined at the same angle as the inclined plate. It is collected in the deepest part and sludge hardly remains on the bottom of the tank after draining sewage. Therefore, in a storage tank having a bottom surface of this shape, sludge hardly remains on the bottom surface after draining sewage or the like.

Next, the inclined plate of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view along the flow direction of an example of a storage tank using the inclined plate of the present invention, in which (a) is storing sewage and the like, (b) is discharging stored sewage and the like. The state (c) shows the state after discharge. 2A and 2B show an example of an inclined plate in which grooves are arranged in parallel on the upper surface. FIG. 2A is a perspective view, and FIG. 2B is a cross-sectional view perpendicular to the inclination of the inclined plate. FIG. 3 is a cross-sectional view of another example of the groove shape of the inclined plate, in which (a) is a groove having a concave cross section, and (b) is a groove having a corrugated cross section. FIG. 4 is a cross-sectional view of an example in which the concrete mold material is used as it is as a zigzag inclined plate. FIG. 5 is a cross-sectional view along the flow direction of an example of a storage tank having a flat bottom surface.

In the example of FIG. 1, sewage or the like flows into the storage tank 1 from the inflow pipe 12. The inclined plate 2 is arrange | positioned at the bottom face 11 of the storage tank 1 so that it may become low along the flow directions (F), such as a sewage. A water collecting groove 13 is provided at the deepest side of the inclined plate 2 of the storage tank 1 in a direction perpendicular to the inclination, and a suction port (not shown) of a drain pump (not shown) is provided at the deepest part of the water collecting groove 13. It has been. The drainage of the sewage 5 and the sludge 51 is performed by this drainage pump.

Sedimentable solids (sludge etc.) 51 in the sewage 5 etc. are deposited on the inclined plate 2. The accumulated sludge 51 is moved downward along the inclination of the inclined plate 2 by placing the valley 31 of the groove 3 of the inclined plate 2 on the flow (F) of the sewage when discharging the sewage 5. Go.

In FIG. 1, two storage tanks 1 may be arranged in parallel if necessary so that storage and discharge of sewage 5 and the like can be performed alternately. In the example of FIG. 1, only one of them is shown. During the storage of the sewage 5 or the like 5 in FIG. 1A, the sludge 51 or the like settles on the inclined plate 2 provided on the bottom surface 11 of the storage tank 1 and sequentially accumulates. When the sewage 5 is full or the sewage 5 is discharged by that time, the sludge 51 that has settled and accumulated on the bottom surface 2 of the storage tank, as shown in FIG. It will be discharged together with the waste water on F). When the drainage is completed, as shown in FIG. 1C, the sludge 51 that has accumulated on the bottom surface 2 of the storage tank 1 is completely discharged, and the sludge 51 does not remain in the storage tank 1.

As shown in FIG. 2, a groove 3 having a triangular cross section is provided on the surface of the inclined plate 2 along the flow direction (F) of sewage or the like. The groove 3 has a zigzag shape, and sludge 51 or the like that has settled on the zigzag inclined surface 32 or the ridge line portion 33 is collected in the valley portion 31 along the inclined surface 32.

The inclined surface 32 of the groove 3 is an elongated groove plate having a width of about 100 mm to 400 mm and a length of about 1500 mm to 2,000 mm. The grooves 3 are formed by combining the groove plates in a zigzag shape using a dedicated fixing bracket 4. That is, the anchor columns 411 and 421 of the peak fixing part 41 and the valley fixing tool 42 are fixed to the bottom surface 11 of the storage tank 1, and the elongated plates constituting the inclined surface 32 on the receiving bars 412 and 422 are bolts or the like (see FIG. (Not shown).

The inclination of the trough 31 of the groove 3 becomes the inclination of the inclined plate 2. Therefore, if the bottom surface 11 of the storage tank 1 is an inclined surface having a necessary angle, the inclined plate 2 can be easily attached. When attaching to the storage tank 1 on the horizontal bottom surface, the length under the neck of the support column 411 of the fixing bracket 4 may be sequentially changed so that a necessary inclination angle can be obtained.

Furthermore, as shown in FIG. 4, when concrete is cast on site, a concrete mold material that also serves as a groove plate after construction is assembled in a zigzag shape on the bottom surface 11 of the storage tank 1 and anchors are driven in. The inclined plate 2 may be used as it is without being removed after the concrete is hardened.

(Example 1)
Using a storage tank having the structure shown in FIG. 1, an inclined plate in which grooves having a thickness of 15 mm, a width of 90 mm, and a length of 60 cm made of glass fiber reinforced rigid urethane foam are combined and grooves having a zigzag cross section are arranged in parallel. I assembled 4 piles.

The inclination angle of the inclined plate was set to 10 degrees along the flow direction such as sewage, and the inclination angle of the groove in the direction perpendicular to the inclined plate direction was set to 30 degrees from the horizontal direction. This was installed on the entire bottom surface of the storage tank having a width of 80 cm, a length of 80 cm along the inclined surface, and a bottom depth of 1 m at the inlet portion such as sewage.

From the longitudinal direction of this storage tank, model sewage containing 2% of porcelain flows continuously at a flow rate of 1.7 L / second, and is left for 1 hour after the storage tank is full. It was discharged under natural flow.

After draining the model sewage, the interception rate of sediment sludge remaining on the bottom inclined plate of the storage tank was obtained. The total amount of sludge input in the model sewage was determined as the product of the average SS concentration of the influent water and the total flow rate. Collect the entire amount of sludge, etc. remaining on the bottom of the reservoir in a glass bottle, filter it (filter paper: Advantech, No5C), dry it with a hot air dryer at a temperature of 115 ° C. for 2 hours, and dry the ceramic The stone powder weight was determined and used as the total amount of accumulated sludge, and the average interception rate of sludge was calculated by the following formula. The results are shown in Table 1.

Sludge average interception rate (%) = ((total amount of sludge input-total amount of accumulated sludge) / total amount of sludge input) x 100

(Example 2)
The average interception rate of sludge was calculated in the same manner as in Example 1 except that the angle of the inclined plate was 3 degrees. The results are also shown in Table 1.

(Example 3)
The average sludge collection rate was calculated in the same manner as in Example 1 except that the angle of the inclined plate was 20 degrees. The results are also shown in Table 1.

(Example 4)
The average interception rate of sludge was calculated in the same manner as in Example 1 except that the inclination angle in the direction perpendicular to the flow direction of the sewage in the groove was 10 degrees from the horizontal direction. The results are also shown in Table 1.

(Example 5)
The average interception rate of sludge was calculated in the same manner as in Example 1 except that the inclination angle in the direction perpendicular to the flow direction of the sewage in the groove was 45 degrees from the horizontal direction. The results are also shown in Table 1.

(Comparative example)
For comparison, an inclined plate made of a flat plate without a groove was arranged on the bottom surface of the same storage tank as in Example 1 so as to have the same inclination direction as in Example 1. The inclination angle was 0 degrees (Comparative Example 1), 10 degrees (Comparative Example 2), 20 degrees (Comparative Example 3), and 30 degrees (Comparative Example 4), and the average sludge collection rate was the same as in Example 1. Calculated. The results are also shown in Table 1.

It is sectional drawing along the flow direction of an example of the storage tank using the inclination board of this invention, (a) is the state which is storing sewage etc., (b) is the state which is discharging the stored sewage, c) shows the state after discharge. An example of the inclination board by which the upper surface was made into the groove | channel of a zigzag shape is shown, (a) is a perspective view, (b) is sectional drawing of a right angle direction with the inclination of an inclination board. It is sectional drawing of the groove shape other example of an inclination board, (a) is a groove | channel where a cross section is a concave shape, (b) is a groove | channel where a cross section is a wave shape. It is sectional drawing of an example which used the concrete formwork material as a zigzag inclined board as it is. It is sectional drawing along the flow direction of an example of the storage tank whose bottom face is a horizontal flat plate.

DESCRIPTION OF SYMBOLS 1 Reservoir 11 Reservoir bottom 12 Inlet pipe 13 Water collecting groove 2 Inclined plate 3 Groove 31 Groove valley 32 Groove inclined surface 4 Fixing tool 41 Mountain fixing tool 42 Valley fixing part 5 Sewage etc. 51 Sedimentable solid ( Sludge)
F Flow direction of sewage

Claims (2)

Sewage an inclined plate made of a synthetic resin which is placed on the bottom surface of the reservoir to be temporarily stored, a plurality of concave grooves along the inclination direction of the inclined plate on the upper surface of the inclined plate, inclined plate slope of the concave groove An inclined plate, wherein the cross-sectional shape perpendicular to the direction is a zigzag shape in which substantially triangular shapes are continuous, and the valley direction of the concave groove is inclined at the same angle as the inclined plate. 2. A storage tank in which sewage is temporarily stored, wherein the inclined plate according to claim 1 is arranged on the bottom surface of the storage tank so that the inclination is higher in the inflow portion direction of the sewage and lower in the discharge portion direction of the sewage. A sewage storage tank.