JP2000015281A - Suspended matter removing apparatus for aeration tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspended matter removing apparatus, in an aeration tank, especially, a batchwise sludge treatment tank in an aeration process or a stirring process, capable of sucking and discharging suspended matter effectively without providing a suspended matter gathering means, capable of always following the fluctuations of the water level in the tank, suppressing the whirling-up of the mixed liquid of the aeration tank at the peripheral edge of a suspended matter suction port and capable of discharging the suspended matter along with a small amt. of a liquid (aeration tank mixed soln.) while involving air. SOLUTION: A suspended matter removing apparatus for an aeration tank is equipped with a recovery plate member 4 provided with a suspended matter suction port 5a removing suspended matter 30, a suspended matter discharge apparatus 8 comprising the discharge means 6 formed so as to be connected to the suspended matter suction port 5a and the holding device 2 for holding the recovery plate member 4 of the suspended matter discharge apparatus 8 under the surface of the mixed soln. in the aeration tank. The holding device 2 is pref. the float 2 attached to the suspended matter discharge apparatus 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for removing suspended matter installed on the water surface of an aeration tank, and more particularly to an apparatus for removing suspended matter installed in a batch type activated sludge treatment tank during an aeration step and a stirring step.

[0002]

2. Description of the Related Art In a sewage treatment facility such as a sewage treatment plant, suspended matter (scum) generated in an aeration tank or the like deteriorates the quality of treated water or impairs aesthetic appearance. Odors due to suspended matter may also be a problem. Such suspended matter is a substance in which sludge adheres or gas is dissolved, with oils and fats, garbage, hair, and the like contained in the sewage as nuclei, and floats on the water surface of the aeration tank.

[0003] Conventionally, a floating tank or a flight scraping-type floating substance removing device has been used in a distribution tank provided between a sedimentation basin or an aeration tank and a sedimentation basin.
There was a disadvantage that the equipment cost was high.

[0004] In particular, in batch activated sludge treatment, which is a typical biological treatment of sewage treatment, inflow, stirring,
Since aeration, sedimentation, and discharge are repeated, there is a problem that suspended matter is difficult to be removed and is accumulated in the tank. Therefore, in a conventional batch type activated sludge treatment tank, the inside of the tank flows using a float pump type device, a fixed overflow weir type device, a supernatant water discharge device, or a removal device combining some discharge devices. During the precipitation or discharge process
The suspended matter was removed. Therefore, in any case, in order to remove suspended matters on the water surface, the suspended matters must be collected in a suspended matter removing device. Usually, there is a problem that a mechanical, wind, or hydraulic (using a nozzle) device must be separately installed.

In a batch activated sludge treatment tank having a large fluctuation in water level, suspended matter is hardly removed during the aeration step and the stirring step. Even if suspended matter is removed, the discharge water level must be set. Is very difficult, and a large amount of the mixed solution in the aeration tank is discharged. In addition, when removing suspended matter during the sedimentation or discharge process, the suspended matter removal device must always follow the water level fluctuation of the batch activated sludge treatment tank, and the suspended matter removal device follows the fluctuating water level. There is also a problem that a mechanism for moving the workpiece must be provided.

[0006] The suspended matter suction port of the ordinary suspended matter removal device is
In many cases, the tube has an open end. The length of the peripheral edge of the suspended matter inlet is short, and it is installed upward below the water surface. Therefore, the overflow load at the periphery of the suspended matter inlet (overflow water volume per day, per unit length. Unit: m ³ / m ·
Sun) is large, and the mixed solution in the aeration tank tends to spring up around the periphery of the floating substance inlet. Due to the rise, the amount of the mixed liquid in the aeration tank sucked into the floating material suction port is much larger than the amount of the floating material sucked, and there is a problem that the efficiency is poor.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a means for collecting suspended matters in an aeration tank which is always in a fluidized state by aeration and agitation, particularly in a batch activated sludge treatment tank in an aeration step and a stirring step. Without the installation of a floating material, it is possible to effectively suck and discharge suspended matter, always follow the fluctuation of the water level in the tank, further suppress the springing of the aeration tank mixture around the periphery of the suspended matter suction port, and reduce the amount of suspended matter It is an object of the present invention to provide a suspended matter removing device capable of discharging air while entraining air together with the liquid (aeration tank mixed liquid). Many devices for removing suspended matters floating on the water surface in a stationary state have been invented and devised so far, but the present suspended matter removing device was invented based on a completely different idea from the conventional technology. Things.

[0008]

According to a first aspect of the present invention, there is provided an apparatus for removing suspended matter from an aeration tank, comprising: a collection plate member provided with a suction port for sucking suspended matter; and a discharge part provided to be connected to the suction port. And a holding means for holding the recovery plate member below the surface of the aeration tank.

[0009] It is preferable that the holding device is a floating tool attached to the floating substance discharging means.

It is preferable that one or more floating substance guide plates are provided, one end of which is fixed to the upper surface of the recovery plate member and the other end of which is provided upright or inclined so as to protrude from the water surface of the aeration tank.

[0011] The aeration tank, which is a batch type activated sludge treatment tank, uses the apparatus for removing suspended matter for an aeration tank according to the present invention, whereby stirring,
Even if aeration, precipitation, and discharge are repeated, suspended matter can be effectively removed.

[0012]

1 to 3 show an embodiment of the present invention.
Shown in FIG. 1 is a perspective view showing an embodiment of the suspended matter removing apparatus of the present invention installed in a rectangular aeration tank, and FIG. 3 is a plan view thereof. FIG. 2A is a plan view of the suspended matter removing device, and FIG. 2B is a side view of the suspended matter removing device.

The apparatus for removing suspended matter according to the present embodiment has a flat collecting plate member 4 having a suspended matter suction port 5a, and one end attached to one surface (the lower surface in the figure) of the collecting plate member 4. Transfer pipeline mounting part 5 communicating with suction port 5a
And a transfer line 6 connected to the transfer line mounting portion 5 and communicating with the transfer line mounting portion 5 and the suspended matter suction port 5a.
And a pump 7 connected to the transfer pipeline 6, and a frame 1 holding the recovery plate member 4 with the surface on which the transfer pipeline mounting portion 5 is mounted facing downward and the suspended matter suction port 5 a facing upward.
And a float 2 as a holding means.

The float 2 is made of polypropylene,
It is a hollow container with gas sealed inside, and has buoyancy and corrosion resistance to water. In addition, the float 2 is arranged such that the suspended matter suction port 5a, that is, the upper surface of the recovery plate member 4 is placed on the water surface or at a fixed position with respect to the water surface, for example, 0 to 50 below the water surface.
In order to hold the float at 2 mm, the member for attaching the float 2 to the frame 1 is constituted by a long screw or the like, and the float 2 is fixed to the frame 1 by a nut or the like, and the position of the collection plate member 4 can be finely adjusted by the tightening amount of the long screw. Like that.

The recovery plate member 4 is manufactured by processing stainless steel (SUS304 or the like) having a thickness of about 1 to 10 mm. The peripheral portion of the recovery plate member 4 may be bent into an L-shaped cross section or provided with a turn of an appropriate shape. The shape of the collection plate member 4 is basically a square or a rectangle, but may be a circle or an ellipse. In addition, a triangle is effective when placed at the corner of a rectangular aeration tank.

During the aeration step, the batch activated sludge treatment tank 20
When the aeration and stirring device 21 installed at the center of the aquarium is operated, a flow of the aeration tank mixed solution is generated outward from the center on the water surface, and the floating substance 30 moves by this flow (FIG. 3). Since the ordinary batch-type activated sludge treatment tank 20 is rectangular, suspended matter is collected at four corners. Therefore, the suspended matter removing device of the present invention is installed in at least one place near the four corners in the batch type activated sludge treatment tank 20, and the upper surface of the recovery plate member 4 having the suspended matter suction port 5a is aerated ( Adjustment is made with the mounting member of the float 2 so as to be 0 to 50 mm below the water surface during (stirring).

It is important that the water depth on the upper surface of the recovery plate member is adjusted to such an extent that the suspended matter is sucked in while entraining the air together with the mixed solution in the aeration tank, and is not limited to the above value. That is, if the water depth on the upper surface of the recovery plate member is too deep, only the mixed solution in the aeration tank is sucked, and the suspended matter is hardly removed. On the other hand, if the water depth is too shallow, even if the suspended matter is approaching the suction port, the air intake is overwhelmingly given priority, so that the suspended matter may not be removed in some cases. Therefore, the water depth on the upper surface of the recovery plate member must be adjusted according to the situation.

The principle by which the present suspended solids removing apparatus removes suspended solids is as follows.

(1) The suspended matter floating on the water surface of the aeration tank is pushed by the flow in the tank in the direction in which the suspended matter removing device is provided.

(2) On the recovery plate member provided immediately below the water surface, the suspended matter rests on a small amount of liquid (aeration tank mixture).

(3) Since the recovery plate member swings up and down due to the flow in the tank, a small amount of suspended matter on the mixed solution in the aeration tank also moves on the recovery plate member.

(4) The suspended matter moving on the collection plate member is finally sucked into the suction port while being entrained by the air together with the mixed solution in the aeration tank, and is discharged.

By repeating this operation, suspended matter is efficiently removed, and the mixed solution in the aeration tank is not discharged more than necessary.

When the pump 7 is operated, first, the suspended matter 30 on the collecting plate member 4 is sucked, and at the same time, the flow of the mixed solution in the aeration tank toward the suspended matter suction port 5a is generated on the water surface. The suspended matter 30 around the collection plate member 4 is carried by this flow, moves on the upper surface of the collection plate member 4, is collected to the suspended matter suction port 5a, and does not stagnate. Inhaled. The sucked suspended matter 30 is discharged out of the batch type activated sludge treatment tank 20 by the pump 7 and the transfer line 6.

As the holding means of the suspended matter discharge device 8, as described above, in addition to using the float (float), as in the case of a treated water discharge device (decanter, not shown) used in the discharge step. Alternatively, a mechanism that mechanically follows the vertical movement of the water surface with an arm member or a wire member may be used. Electric or hydraulic pressure may be used for the mechanism.

As means for discharging suspended matter, as described above, a method for forcibly discharging the suspended matter by stopping the operation of the transfer device (pump), a drain pipe or a pit connected to the suspended matter inlet 5a, etc. And a method of forcibly discharging the water by operating a water pump provided in the pit by operating / stopping the submersible pump provided in the pit.

The operation of stopping the operation of the transfer device and the operation of opening and closing the valve are performed by using a timer or the like, after the sedimentation process and the discharge process are completed, and after the process proceeds to the aeration process or the agitation process, the suspended matter spreading on the tank water surface It is effective to execute for a certain period of time (3 minutes to 30 minutes) at the time when the gas flows toward the suspended matter removing device.

In the batch type activated sludge treatment tank, actinomycetes abnormally grow depending on the season and operating conditions, and the suspended matter foams, and at the time of aeration, the suspended matter further foams due to the mixing of air, and the suspended matter layer may reach 20 cm or more. . As described above, since the suspended matter during the aeration step and the stirring step thickly covers the water surface of the aeration tank, the recovery plate member is adjusted so as to be located immediately below the water surface of the mixed solution of the aeration tank in the tank. Thereby, even if a large amount of suspended matter is present, the suspended matter can be quickly and efficiently discharged.

In the embodiment shown in FIG. 4, a plurality of holes 4a are provided in the recovery plate member 4.

The holes 4a are effective in stabilizing the suspended matter removing device floating in the batch type activated sludge treatment tank in which the mixed solution of the aeration tank flows, against the fluctuation caused by the flow of the mixed solution of the aeration tank. It also serves to replenish the aeration tank mixture which moves suspended matter on the collection plate member.

In the embodiment shown in FIG.
Is provided.

When the oil content is large or the flow in the tank is weak, the floating substance guide plate 3 may be provided to provide the floating substance suction port 5a.
It facilitates the formation of vortices in the vicinity, and is effective in collecting suspended matter.

The floating material guide plate 3 may have a flat shape and may be provided radially outward from the periphery of the floating material suction port 5a. Alternatively, as shown in FIG. Alternatively, it may be provided in a curved shape and provided radially outward from the periphery of the suspended matter suction port 5a, or may be attached to the collection plate member 4 at an angle. The shape and arrangement of the floating substance guide plate 3 stabilizes the vortex flow of the floating substance and the mixed liquid in the aeration tank sucked into the floating substance suction port 5a, and collects the floating substance more effectively to the floating substance suction port 5a. be able to.

In the embodiment shown in FIG.
Is separated from the floating substance suction port 5a, but may be arranged in contact therewith.

In the suspended matter removing device of the present invention, since the suspended matter suction port 5a is provided on the upper surface of the collection plate member 4, the overflow load at the suspended matter suction port 5a is applied to the peripheral edge of the collection plate member 4. . Since the perimeter of the recovery plate member 4 is longer than the perimeter of the suspended matter suction port 5a, the overflow load can be reduced. Therefore, it is effective in minimizing the amount of the mixed liquid in the aeration tank sucked into the suspended matter suction port 5a together with the suspended matter.

In the previous embodiment, the shape of the upper surface of the collecting plate member 4 was made flat, but as in the embodiment shown in FIG. The recovery plate member 4 may be processed so as to have a downward slope from the mouth 5a toward the periphery, that is, to have a middle height, and also to discharge the suspended matter 30 while minimizing the amount of the aeration tank mixture to be sucked. It is effective for

Further, by adjusting the position of the floating substance suction port 5a with respect to the water surface by the mounting member of the float 2, the central portion does not hinder the suction of the floating substance 30 and the mixing of the aeration tank below the floating substance 30 is prevented. Inhalation of liquid can be prevented.

The suspended matter removing apparatus of the present invention can be applied to a biological water treatment reaction tank which is an aeration tank in a broad sense in which suspended matter is likely to be generated, in addition to the batch type activated sludge treatment tank. For example, in the oxidation ditch (oxidation ditch), a baffle is provided near the water surface of the treatment flow path to prevent the flow of suspended matter, and thereby the suspended matter removing device of the present invention is installed on the upstream side where the suspended matter accumulates. The apparatus for removing suspended matter according to the present invention may be installed in a pit for advancing to a sedimentation basin. In the case of the activated sludge treatment tank of the extrusion flow type, it is effective to install the suspended matter removing device of the present invention at a corner near the discharge part.

The apparatus for removing suspended matter according to the present invention not only removes suspended matter from the aeration tank, but also intentionally sucks the mixed liquid in the aeration tank for the purpose of extracting excess sludge particularly in the batch type activated sludge treatment tank.・ It may be discharged. In this case, an effect is obtained that a mechanical device for sludge extraction and a complicated operation can be omitted.

[0040]

The apparatus for removing suspended matter according to the present invention is installed in an aeration tank, particularly in a batch type activated sludge treatment tank, and removes suspended matter during an aeration step or a stirring step in which the tank is flowing. This is an apparatus for removing suspended matter, which is disposed around the corner of the aeration tank, and has an effect that it is not necessary to separately install a mechanical device or the like for collecting suspended matter. Also,
By providing a holding means such as a float, it is possible to always follow the water level fluctuation in the tank.

Further, since the suspended matter suction port is provided on the recovery plate member, the overflow load can be suppressed low, and the rise and discharge of the mixed solution in the aeration tank can be suppressed as much as possible.

The upper surface of the recovery plate member is machined so that the floating material suction port is at the top and the slope is lowered toward the periphery, and the recovery plate member has a medium-high structure. Can be minimized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which an embodiment of a suspended matter removing apparatus according to the present invention is floated in an aeration tank.

FIG. 2A is a plan view showing an embodiment of a suspended matter removing device according to the present invention. FIG. 2B is a side view showing an embodiment of the suspended matter removing device of the present invention.

FIG. 3 is a plan view showing an embodiment of the suspended matter removing apparatus according to the present invention floating in an aeration tank.

FIG. 4 is a plan view showing another embodiment of the suspended matter removing device of the present invention.

FIG. 5 is a plan view showing another embodiment of the suspended matter removing device of the present invention.

FIG. 6 is a partially cutaway side view showing another embodiment of the suspended matter removing device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame 2 Float 3 Suspended matter guide plate 4 Collection plate member 4a Hole 5 Transfer line attachment part 5a Floating matter suction port 6 Transfer line 7 Floating matter suction device 8 Floating matter discharge device 20 Batch activated sludge treatment tank 21 Aeration and stirring Apparatus 30 suspended matter

Claims (4)

[Claims] 1. A collection plate member provided with a suction port for sucking suspended matter in an aeration tank, a suspended matter discharge means provided with a discharge portion connected to the suction port, and the collection plate member A suspended matter removing device for an aeration tank, comprising a holding means for holding the material below the surface of the aeration tank. 2. The apparatus for removing suspended matter for an aeration tank according to claim 1, wherein the holding means is a float attached to the suspended matter discharging means. 3. One or two or more of the collection plate members, one end of which is fixed to the upper surface of the collection plate member and the other end of which is provided upright or inclined so as to protrude from the water surface of the aeration tank. The floating substance removing device for an aeration tank according to claim 1 or 2, further comprising a floating substance guide plate. 4. The apparatus for removing suspended matter for an aeration tank according to claim 1, wherein the aeration tank is a batch type activated sludge treatment tank.