JP3762771B2 - Defoaming device and defoaming method for aeration tank - Google Patents

Description

  The present invention relates to a defoaming apparatus and a defoaming method that can effectively and inexpensively eliminate bubbles inevitably generated by aeration treatment.

  In sewage treatment such as wastewater from food processing plants and household wastewater, aeration treatment using activated sludge is suitably used. FIG. 4 illustrates a part of the sewage treatment, and shows a primary sedimentation basin 20, an aeration tank 21, a final sedimentation basin 22, and a sterilization treatment basin 23.

  Waste liquid from a food processing factory or the like is first collected in the primary sedimentation basin 20 and solids are removed by precipitation. Next, the waste liquid from which the solid content has been removed is supplied to the aeration tank 21. In the aeration tank 21, sludge containing aerobic microorganisms that decompose organic matter (activated sludge) is added, and air is continuously supplied to stir the sludge to decompose organic matter in the waste liquid.

  Microorganisms that have absorbed dirt in the aeration tank sink and become spongy, so that the supernatant liquid of the final sedimentation basin 22 located downstream of the aeration tank 21 is clean. Therefore, the supernatant liquid is supplied to the sterilization pond 23 and sterilized with sodium hypochlorite or the like and then released naturally.

  Thus, aeration treatment plays an important role in sewage treatment, but in an aeration tank, in order to activate aerobic microorganisms, it is always necessary to supply air and circulate wastewater. For this reason, bubbles that have floated float on the surface of the aeration tank, but if left untreated, sewage bubbles overflow from the aeration tank, and it is necessary to eliminate these bubbles. Because of the necessity of such defoaming, conventionally, water has been ejected from a nozzle, and water has been sprayed to the location where the bubbles gather.

  However, since water formed in a beam shape using a nozzle is applied to the bubbles, there is a problem that only a very narrow range of bubbles can be erased. In addition, if the water ejected from the nozzle is blown away, the range of bubbles hit by water can be expanded, but in this case, the water droplets that hit the bubbles must be small and the defoaming effect is not so much It wasn't.

  Moreover, in the configuration in which water is ejected from the nozzles, water mixed with foreign matters cannot be used to prevent clogging, and tap water or industrial water must be used. And since the aeration process is normally performed continuously without a break, the water discharge process is also performed continuously, and the water bill required for the above-mentioned defoaming process is also a considerable amount. In particular, when a large water droplet is applied to a wide range of bubbles, the amount of water required becomes enormous.

  This invention is made | formed in view of said subject, Comprising: It aims at providing the defoaming method and defoaming apparatus which enable the effective defoaming process in an aeration tank.

In order to achieve the above-mentioned object, the present invention receives an annular pipe arranged in an annular shape at the upper part of an aeration tank and treated water treated in the aeration tank from the downstream side of the aeration tank as defoaming water. A supply pipe that supplies the annular pipe, and a plurality of water spray members disposed at a lower portion of the annular pipe, the water sprinkling member is connected to the upper and lower plate members and the two plate members up and down. It is composed of a rod, the length of the connecting rod, on the basis of the scattering range of Shoawasui, hydraulically defoaming water emitted toward the plate of the lower, and the size of the water droplets are scattered 20 The defoamed water determined to be in a range of ˜70 cm and discharged through the upper plate material rebounds by colliding with the lower plate material, and water droplets of the defoamed water splashing and splashing are sprinkled and defoamed. It is like that.

The present invention also provides an annular pipe disposed in an upper part of the aeration tank and treated water treated in the aeration tank from the downstream side of the aeration tank, and supplies the defoamed water to the annular pipe. Using a defoaming device comprising a supply pipe and a plurality of water spray members arranged at the lower part of the annular pipe, the water spray members are two upper and lower plate members and a connecting rod for connecting the two plate members up and down. The length of the connecting rod is 20 to 20 based on the scattering range of the defoaming water, the water pressure of the defoaming water released toward the lower plate, and the size of the splashed water droplets. The defoamed water that has been determined to be in the range of 70 cm and pierced through the upper plate of the water sprinkling member hits the lower plate and bounces back, and the water droplets of the defoamed water that bounce off and sprinkle are sprinkled. Like to do.

  In the present invention, the annular pipe is preferably configured by connecting a plurality of pipes with a T-shaped pipe (4), and the water sprinkling member is connected to the T-shaped pipe. The T-shaped tube preferably has a base end portion (4a) extending downward perpendicular to the annular pipe and having a larger inner diameter than a tip end portion (4b) connected to the water sprinkling member.

  Moreover, it is preferable that the inner diameter of the supply pipe (2), the annular pipe (1), and the tip part (4b) of the T-shaped pipe is gradually reduced in this order. Further, the two plate members are plane plates made of vinyl chloride, and both end portions (10b) of the connecting rod are inserted and fixed in through holes (12) formed in the corner portion of the plane plate. It is preferable. The connecting rod is preferably a round bar formed to a length of 20 to 70 cm, and the watering member preferably discharges defoaming water from an outlet having an inner diameter of 3 cm or more.

  In the present invention, since water is sprayed from directly above the aeration tank to the bottom, it is not necessary to eject water from the nozzle. Therefore, it is not necessary to use tap water or the like in consideration of clogging, and treated water treated in an aeration tank (typically, supernatant liquid after aeration treatment) can be used, and running costs are extremely low. .

  Hereinafter, based on the Example of this invention, this invention is demonstrated still in detail. FIG. 1 is a schematic plan view showing a defoaming device EQU arranged on the upper part of the aeration tank CH, and FIG. 2 is a partially enlarged view seen from the line AA in FIG. The apparatus EQU includes an annular pipe 1 configured by combining a curved pipe, a straight pipe, and a T-shaped pipe into a rectangular ring shape, a supply pipe 2 that supplies defoaming water from the base end side of the annular pipe 1, and an annular pipe 1 It is comprised centering on the some watering member 3 arrange | positioned at the lower part of this. And this apparatus EQU is continuously operated without a break.

  The defoaming water is supplied from the suction pump arranged in the final sedimentation tank located downstream of the aeration tank CH, and the amount of water to the extent that the inside of the annular pipe 1 is filled with the defoaming water is always supplied from the suction pump. ing. In this embodiment, the supernatant liquid after the aeration treatment is used as the defoaming water. The defoaming water supplied from the suction pump is supplied from the supply pipe 2 to the annular pipe 1 and from the annular pipe 1 to the water sprinkling member 3. Each time it is transmitted, the flow channel becomes narrower in stages.

  As shown in FIG. 2, the T-shaped tube 4 is configured to communicate in three directions, and connects the annular pipe 1 in the horizontal direction and connects the annular pipe 1 and the water spray member 3. The vertical portion of the T-shaped tube 4 is composed of a large diameter portion 4 a and a small diameter portion 4 b, and the small diameter portion 4 b is welded and fixed to the water spray member 3.

  The inner diameter φ of the small-diameter portion 4b is suitably about 1/5 to 1/2 of the inner diameter of the annular pipe 1, but substantially the same amount of water is stably discharged from each of the watering members 3. Thus, the specific inner diameter φ is determined according to the number of watering members 3. However, in order to realize a stable defoaming effect, an inner diameter φ of 3 cm or more is necessary, and it is practical to set the inner diameter φ to around 5 cm. In any of the inner diameters φ, the defoaming water is pressurized by the suction pump so as to be discharged from the small diameter portion 4b.

  As shown in FIGS. 1 and 2, a support wire 5 is stretched over the annular pipe 1. The annular pipe 1 includes both ends of the T-shaped tube 4 and is held by the holding arms 6 at substantially regular intervals. The annular pipe 1 held by the holding arms 6 and 6 is suspended from the support wire 5. It has been. Further, a holding member 7 is disposed on the end side of the annular pipe 1 to hold the annular pipe 1 in a fixed manner.

  As shown in FIG. 3A, the water sprinkling member 4 is centered on upper and lower horizontal plates 8 and 9 made of vinyl chloride and four connecting rods 10 made of stainless steel that connect the upper and lower horizontal plates 8 and 9. It is configured. FIG. 3A is a central cross-sectional view taken along the center of the horizontal plates 8 and 9 (the BB line in FIG. 3B). In this embodiment, the horizontal plate is a square of about 20 cm × 20 cm, and the connecting rod 10 is a round bar having a main body length of about 30 to 35 cm.

  The longer the connecting rod 10, the greater the momentum of the defoamed water that hits the lower horizontal plate 9, and the longer the splashing distance of the splashed water droplets. Therefore, the length of the connecting rod 10 is appropriately in the range of 20 to 70 cm based on the scattering range of the defoaming water, the water pressure of the defoaming water discharged from the small diameter portion 4b, and the size of the water droplets to be scattered. The length is determined. In general, when the length of the connecting rod 10 exceeds 70 cm, the splashed water droplets become too small and the defoaming effect deteriorates. In addition, if the connecting rod 10 is long, the occupying space and the maintainability of the installation work are deteriorated as well as the disadvantage that the space occupied by the present apparatus is widened.

  As shown in FIG. 3B, the upper horizontal plate 8 has an opening hole 11 formed in the center thereof, and a small diameter portion 4b of a T-shaped tube is inserted into the opening hole 11 and welded thereto. . Further, through holes 12 are formed in the corner portions of the upper and lower horizontal plates 8 and 9.

  As shown in FIG.3 (c), in this Example, the connection rod 10 is comprised by the cylindrical main-body part 10a and the small diameter both ends 10b provided with a screw groove. The outer diameter of the main body 10 a is sufficiently larger than the through holes 12 of the horizontal plates 8 and 9, but the outer diameters of both end portions 10 a are slightly smaller than the through holes 12.

  Since the water sprinkling member 3 is composed of the above-described simple structural members, at the time of assembly, both end portions 10b of the four connecting rods 10 are inserted into the through holes 12 of the upper and lower horizontal plates 8 and 9, and the horizontal plates 8 and 9 are inserted. It is only necessary to tighten the nut 12 to the end portion 10b protruding from the end.

  Since the water sprinkling member 3 is configured in this way, the defoamed water supplied from the annular pipe falls from the small-diameter portion 4b of the T-shaped tube 4 and collides with the lower horizontal plate 9 (reflecting plate) vigorously. Then, the splashes are sprinkled around the water sprinkling member 3. In this case, the sprayed spray is not a spray sprayed from a fine nozzle, but is formed by hitting the horizontal plate 9 in a state close to a natural fall, so that the water droplets are large and a defoaming effect is ensured. Demonstrate.

  Further, in this apparatus EQU, the inner diameter of the pipe gradually decreases from the supply pipe 4 through the annular pipe 1 to the T-shaped pipe 4 until it is discharged from the small-diameter portion 4b of the T-shaped pipe 4. So smooth water flow is realized. In addition, since the inner diameter φ of the small diameter portion 4b is 3 cm or more, there is no possibility of clogging even if defoamed water containing foreign matter is used.

  Furthermore, since vinyl chloride is used as the material for the horizontal plate, deterioration due to dirty water is not a problem. In the embodiment, the connecting rod 10 and the nut 12 made of stainless steel are used, but a synthetic resin such as vinyl chloride may be adopted. In the embodiment, a square horizontal plate is used, but other shapes including a circle and an ellipse may be used instead of the square, and a curved plate may be used instead of the horizontal plate.

It is a schematic plan view which shows the structure of the defoaming apparatus which concerns on an Example. It is the enlarged view seen from the AA line of FIG. The watering member is illustrated in detail. It is drawing explaining sewage treatment.

Explanation of symbols

EQ defoaming device 1 annular pipe 2 supply pipe 3 water sprinkling member 8, 9 plate material 10 connecting rod

Claims (7)

An annular pipe arranged in an annular shape at the upper part of the aeration tank, a supply pipe that receives treated water treated in the aeration tank from the downstream side of the aeration tank and supplies it as defoaming water to the annular pipe, and the annular A plurality of watering members disposed at the bottom of the pipe,
The water sprinkling member is composed of two upper and lower plate members and a connecting rod that connects the two plate members up and down,
Determining the length of the connecting rod, a scattering range of Shoawasui, hydraulically defoaming water emitted toward the plate of the lower, in the range of 20~70cm based on the size of the water droplets are scattered And
The defoamed water discharged through the upper plate is bounced off by hitting the lower plate, and water droplets of the defoamed water splashing and splashing are sprinkled to defoam. A defoaming device for an aeration tank. 2. The defoaming device according to claim 1, wherein the annular pipe is configured by connecting a plurality of pipes with a T-shaped pipe, and the water sprinkling member is connected to the T-shaped pipe. The defoaming device according to claim 2, wherein a base end portion of the T-shaped tube that extends downward perpendicular to the annular pipe has a larger inner diameter than a tip end portion connected to the water sprinkling member. The defoaming device according to claim 3, wherein inner diameters of the supply pipe, the annular pipe, and the tip of the T-shaped pipe are gradually reduced in this order. The said two board | plate material is a plane board made from a vinyl chloride, The both ends of the said connection rod are inserted and fixed to the through-hole formed in the corner part of this plane board. The defoaming device according to crab. The defoaming device according to any one of claims 1 to 5 , wherein the water sprinkling member discharges defoaming water from an outlet having an inner diameter of 3 cm or more. An annular pipe arranged in an annular shape at the upper part of the aeration tank, a supply pipe that receives treated water treated in the aeration tank from the downstream side of the aeration tank and supplies it as defoaming water to the annular pipe, and the annular Using a defoaming device comprising a plurality of watering members arranged at the bottom of the pipe,
The water sprinkling member is composed of two upper and lower plate members and a connecting rod that connects the two plate members up and down,
Determining the length of the connecting rod, a scattering range of Shoawasui, hydraulically defoaming water emitted toward the plate of the lower, in the range of 20~70cm based on the size of the water droplets are scattered And
The defoaming water discharged through the upper plate material of the watering member is bounced back against the lower plate material, and the aeration tank in which the defoamed water splashing and splashing is sprinkled to defoam the water Defoaming method.

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