Wastewater treatment apparatus

Abstract

To provide improvement of the wastewater treatment capacity of a wastewater treatment apparatus using wood chips.SOLUTION: A wastewater treatment apparatus 1 for purifying and treating wastewater is provided with: a treatment tank 2 partially or wholly buried underground; a wood chip layer 9 formed by wood chips deposited in the treatment tank 2; an airlift pump 20 disposed outside the treatment tank 2; and a water sending pipe 25 for sending wastewater into the wood chip layer 9. The treatment tank 2 is configured so as to be permeable from inside to outside, wherein the airlift pump 20 has an outer tube 21 extending in a vertical direction into which wastewater is supplied, a lifting pipe 22 arranged inside the outer tube, and an air sending pipe 23 that sends air inside the lifting pipe 22, and one end of the water sending pipe 25 is connected to the lifting pipe 22 and the other end of the water sending pipe 25 is located inside the treatment tank 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a wastewater treatment device for performing a purification treatment of wastewater. [Background technology]

[0002] Wastewater such as miscellaneous wastewater and sewage discharged daily from ordinary houses, apartment buildings, stores, etc. is usually sent to a sewer system and purified in a sewage treatment facility. On the other hand, wastewater generated in areas not connected to a sewer system is purified, for example, in a septic tank and then discharged into rivers or gutters, or discharged into the ground.

[0003] Patent Document 1 discloses a wastewater treatment device for purifying wastewater delivered from a septic tank. This wastewater treatment device includes a treatment tank formed of a water-permeable material buried underground, a wood chip layer formed by filling the treatment tank with small wood chips, and an air lift pump for delivering wastewater to the wood chip layer, the air lift pump being disposed inside the treatment tank.

[0004] In the wastewater treatment device described in Patent Document 1, wastewater is decomposed into carbon dioxide and water by microorganisms living in wood chips filled in a treatment tank. The water purified by the decomposition process permeates into the ground from the side of the treatment tank, which has water permeability. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3878186 Summary of the Invention [Problem to be solved by the invention]

[0006] In order to improve the purification capacity of wastewater in wastewater treatment equipment using small wood chips, it is desirable to increase the capacity of the small wood chips contained in the treatment tank. One possible means for increasing the capacity of the small wood chips is to use a treatment tank with a larger diameter than the treatment tank that was previously used. However, when the wastewater treatment equipment is installed in a facility in a mountainous area, the installation space for the equipment is limited, and it may be difficult to increase the diameter of the treatment tank.

[0007] Another possible means for increasing the capacity of the wood chips is to extend the overall length of the treatment tank and bury it to a deeper position from the ground surface. This allows the capacity of the treatment tank to be increased without increasing its diameter, making it possible to increase the capacity of the wood chips that can be stored in the treatment tank.

[0008] However, when the treatment tank is buried deep underground, the construction becomes more difficult due to the need to excavate the ground deeper. In addition, the deeper the depth from the ground surface to the bottom of the treatment tank, the greater the workload for maintenance work such as replacing the wood chips in the treatment tank and cleaning the inside of the treatment tank.

[0009] Therefore, in order to improve the wastewater treatment capacity of wastewater treatment equipment using small wood chips, other measures must be taken.

[0010] The present invention has been made in consideration of the above circumstances, and has an object to improve the wastewater treatment capacity of a wastewater treatment device that uses small wood chips. [Means for solving the problem]

[0011] The present invention, which solves the above-mentioned problems, is a wastewater treatment device that purifies wastewater, comprising a treatment tank that is partially or completely buried in the ground, a wood chip layer formed by the accumulation of wood chips in the treatment tank, an air lift pump arranged outside the treatment tank, and a water supply pipe that supplies the wastewater to the wood chip layer, wherein the treatment tank is configured to be water permeable from the inside to the outside, and the air lift pump has an outer tube pipe extending vertically through which the wastewater is supplied, a lifting pipe arranged inside the outer tube pipe, and an air supply pipe that sends air inside the lifting pipe, one end of the water supply pipe is connected to the lifting pipe, and the other end of the water supply pipe is located within the treatment tank.

[0012] The wastewater treatment device may have a cleaning pipe connected to an upper end of the lifting pipe, and the upper end of the cleaning pipe may be located at or above the ground surface.

[0013] The wastewater treatment device may have an overflow pipe with a backflow prevention valve, one end of the overflow pipe being connected to the outer tube below the connection point of the water supply pipe to the outer tube, and the other end of the overflow pipe being located within the treatment tank.

[0014] The wastewater treatment device has a drain pipe connected to the outer tube pipe and supplies the wastewater, and the overflow pipe has a first pipeline extending horizontally connected to the outer tube pipe and a second pipeline extending downward from the first pipeline and having a lower end located within the treatment tank, and the axis of the first pipeline may be located lower than the position of the axis of the drain pipe at the connection point between the outer tube pipe and the drain pipe. Effect of the Invention

[0015] According to the present invention, the wastewater treatment capacity of a wastewater treatment device that utilizes small wood chips can be improved. [Brief description of the drawings]

[0016] [Figure 1] 1 is a diagram for explaining a schematic configuration of a wastewater treatment device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing a cross section taken along the line AA in FIG. [Diagram 3] FIG. 13 is a diagram for explaining a schematic configuration of a wastewater treatment device according to another embodiment. [Figure 4] FIG. 13 is a diagram for explaining a schematic configuration of a wastewater treatment device according to another embodiment. [Diagram 5] 5 is a top view of the area around the installation portion of the wastewater treatment device in FIG. 4. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are given the same reference numerals to avoid repetitive explanation. In addition, in drawings including cut surfaces, hatching showing the cut surfaces is partially omitted in order to ensure the visibility of the drawings.

[0018] Fig. 1 is a diagram for explaining the schematic configuration of a wastewater treatment device 1 according to this embodiment, and shows a schematic vertical cross section of the ground where the wastewater treatment device 1 is installed. Fig. 2 is a diagram showing a schematic cross section taken along line AA in Fig. 1.

[0019] The wastewater treatment device 1 includes a treatment tank 2 buried in the ground. The treatment tank 2 is formed in a cylindrical shape having a bottom surface, and a plurality of fine through-holes 3 are formed on the side surface of the cylindrical treatment tank 2. Wastewater in the treatment tank 2 is discharged to the outside of the treatment tank 2 through the through-holes 3 and permeates into the ground, that is, the treatment tank 2 is configured to be permeable from the inside to the outside.

[0020] In this embodiment, the entire treatment tank 2 is buried in the ground, but for example, a part of the treatment tank 2 may be buried in the ground and the remaining part may be exposed above ground. The shape of the treatment tank 2 is not limited to a cylindrical shape.

[0021] The treatment tank 2 is placed on a concrete slab 4 laid on the bottom surface of the excavated ground. A waterproof sheet (not shown) is provided between the bottom surface of the treatment tank 2 and the concrete slab 4. In addition, a crushed stone layer 5 is formed on the side of the treatment tank 2 by filling the excavated ground with crushed stone. The height of the crushed stone layer 5 is approximately the same as the height of the treatment tank 2.

[0022] A cylindrical adjuster 6 is attached as a part for raising the upper end of the treatment tank 2. The upper end of the adjuster 6 is located at the ground surface GL, and an openable and closable lid 7 for covering the upper opening of the adjuster 6 is attached to the upper end of the adjuster 6.

[0023] The upper surface of the crushed stone layer 5 is covered with a waterproof sheet (not shown), and the topsoil layer 8 is formed on the waterproof sheet by backfilling the soil generated by excavation of the ground. In other words, the side of the adjuster 6 is the topsoil layer 8.

[0024] Inside the treatment tank 2, small wood chips are piled up to form a small wood chip layer 9. Aerobic microorganisms live in the small wood chips, and organic matter in the wastewater pumped into the treatment tank 2 is purified by being decomposed by the aerobic microorganisms. The small wood chips used are preferably those having a honeycomb structure such as Marton Chips (registered trademark), but the shape of the small wood chips is not particularly limited, and they may be granular like sawdust, or may be in the shape of a plate or rod. Small chips of these shapes may also be mixed in.

[0025] A vertically extending water sample pipe 10 is installed near the side of the treatment tank 2. An inlet hole for the wastewater from the treatment tank 2 is formed at the bottom of the water sample pipe 10, and the wastewater from the treatment tank 2 flows into the water sample pipe 10. This makes the water level in the water sample pipe 10 the same height as the water level in the treatment tank 2. Since small wood chips have accumulated inside the treatment tank 2, it is difficult to check the water level inside the treatment tank 2, but the water level in the treatment tank 2 can be estimated by opening the lid 7 and checking the water level in the water sample pipe 10.

[0026] An air lift pump 20 is provided on the side of the treatment tank 2. The air lift pump 20 has an outer cylinder pipe 21, a water lift pipe 22 arranged inside the outer cylinder pipe 21, and an air supply pipe 23 that sends air into the water lift pipe 22.

[0027] The outer cylinder pipe 21 is a pipe body having a bottom surface, and is placed on the concrete slab 4. The outer cylinder pipe 21 extends along the vertical direction, and the upper end opening of the outer cylinder pipe 21 is plugged with a plug to prevent wastewater from overflowing from the upper end of the outer cylinder pipe 21.

[0028] The lift pipe 22 has a smaller diameter than the outer tube pipe 21 and extends vertically. The lower end of the lift pipe 22 is located near the bottom surface of the outer tube pipe 21, and the upper end of the lift pipe 22 is located higher than the upper end of the outer tube pipe 21.

[0029] The air pipe 23 is constructed by connecting a plurality of piping components to each other. The portion of the air pipe 23 located inside the water rise pipe 22 has a smaller diameter than the water rise pipe 22 and extends vertically. The lower end of the air pipe 23 located inside the water rise pipe 22 is located near the lower end of the water rise pipe 22. The upper end of the air pipe 23 is connected to a blower 24 as an air supply source installed on the ground surface GL.

[0030] Air supplied from the blower 24 is discharged through the air pipe 23 into the vicinity of the lower end of the rise pipe 22, and the discharged air rises inside the rise pipe 22. This creates an air lift effect inside the rise pipe 22, and the wastewater inside the outer tube 21 flows into the lower end of the rise pipe 22 and rises inside the rise pipe 22.

[0031] A water supply pipe 25 for supplying wastewater to the wood chip layer 9 is attached to the side of the treatment tank 2. One end of the water supply pipe 25 is connected to the upper end of the lift pipe 22, and the other end of the water supply pipe 25 is located inside the treatment tank 2. The water supply pipe 25 extends horizontally from the outside of the treatment tank 2 to near the center of the inside of the treatment tank 2.

[0032] A sprinkler pipe 26 is provided at the tip of the water supply pipe 25 to sprinkle the wastewater flowing inside the water supply pipe 25 onto the wood chip layer 9. The wastewater rising inside the lift pipe 22 is passed through the water supply pipe 25 and sprinkled from the sprinkler pipe 26 onto the upper surface of the wood chip layer 9. The structure of the water supply pipe 25 is not particularly limited as long as it is possible to supply the wastewater to the wood chip layer 9.

[0033] A drain pipe 27 leading to a drainage source such as a septic tank is connected to the side of the outer tube 21. The drain pipe 27 is connected horizontally to the side of the upper end of the outer tube 21, and the drainage water delivered from the drain pipe 27 passes through the outer tube 21, the lift pipe 22, the water delivery pipe 25, and the sprinkler pipe 26 before being delivered to the wood chip layer 9.

[0034] An overflow pipe 28 with a backflow prevention valve is provided below the water supply pipe 25. One end of the overflow pipe 28 is connected to the side of the outer cylinder pipe 21, and the other end of the overflow pipe 28 is located inside the treatment tank 2. When such an overflow pipe 28 is installed, it is possible to prevent backflow of wastewater through the drain pipe 27 to a facility on the wastewater source side (for example, an ordinary house, an apartment building, or a store) when the operation of the blower 24 stops due to a power outage, a malfunction, or the like.

[0035] More specifically, when the blower 24 stops operating, the pumping of water in the lift pipe 22 stops, and the water level of the wastewater stored in the outer tube 21 rises. At this time, because an overflow pipe 28 is connected to the side of the outer tube 21, the wastewater is sent from the overflow pipe 28 to the wood chip layer 9. This prevents the water level of the wastewater in the outer tube 21 from rising above a predetermined height, and makes it possible to suppress backflow of the wastewater into the facility on the wastewater source side.

[0036] Furthermore, since a check valve is attached to the overflow pipe 28, even if the water level in the treatment tank 2 rises above the installation height of the overflow pipe 28, there will be no backflow of wastewater from the overflow pipe 28 to the outer tube pipe 21.

[0037] In this embodiment, the overflow pipe 28 is composed of a first pipe 28a extending horizontally and connected to the side surface of the outer tube 21, and a second pipe 28b extending downward from the first pipe 28a. The lower end of the second pipe 28b is located inside the wood chip layer 9.

[0038] From the viewpoint of enhancing the effect of suppressing the backflow of wastewater toward the wastewater source side described above, it is preferable that the pipe axis of the first pipe 28a is located at a position lower than the pipe axis of the drain pipe 27 at the connection point between the outer tube pipe 21 and the drain pipe 27. This makes it easier for the wastewater to flow into the overflow pipe 28 when the water level of the wastewater in the outer tube pipe 21 rises, and the amount of wastewater that backs up toward the drain pipe 27 can be suppressed.

[0039] From the viewpoint of enhancing the effect of suppressing backflow of wastewater to the wastewater source side, it is preferable that the lowest point (the lowest part in the vertical direction) of first pipe 28a at the connection point with outer tube pipe 21 is located lower than the lowest point of drain pipe 27 at the connection point with outer tube pipe 21. As a result, when the water level of wastewater in outer tube pipe 21 rises due to the stop of blower 24, the wastewater will flow into overflow pipe 28 before drain pipe 27, and the amount of wastewater backflowing into drain pipe 27 can be suppressed.

[0040] A cylindrical case 29 having a bottom surface is provided to the side of the adjuster 6. The upper end of the water lift pipe 22 penetrates the bottom surface of the case 29, and an openable / closable lid 30 is attached to the upper opening of the water lift pipe 22. The upper end of the case 29 is located at the ground surface GL, and an openable / closable lid 31 is attached to the upper opening of the case 29. The case 29 forms a space for cleaning the inside of the air lift pump 20.

[0041] Inside the air lift pump 20, fine particles contained in the wastewater may adhere to or accumulate inside the pipes, causing clogging of the piping. For this reason, the inside of the air lift pump 20 is cleaned as part of regular maintenance work. As a specific cleaning method, for example, after opening the lid 31 of the case 29 and the lid 30 of the lift pipe 22, a high-pressure cleaning hose is inserted from the upper end of the lift pipe 22, and high-pressure water is supplied in this state to perform high-pressure cleaning inside the air lift pump 20. As a result, fine particles adhering to or accumulating inside the lift pipe 22 and the outer cylinder pipe 21 are discharged to the outside of the air lift pump 20.

[0042] The schematic configuration of the wastewater treatment device 1 according to this embodiment has been described above. In this wastewater treatment device 1, the air lift pump 20 is disposed outside the treatment tank 2. This makes it possible to expand the storage area for small wood chips in the treatment tank 2 compared to conventional devices in which the air lift pump is disposed inside the treatment tank. This makes it possible to increase the amount of small wood chips that can be stored, thereby improving the wastewater treatment capacity of the wastewater treatment device 1.

[0043] Furthermore, since the air lift pump 20 is disposed outside the treatment tank 2, the workability is improved, for example, when replacing the small wood chips in the treatment tank 2. For example, in a conventional device in which the air lift pump is disposed inside the treatment tank, small wood chips get into the gap between the inner surface of the treatment tank and the air lift pump, and it is not easy to remove the small wood chips remaining in the gap. On the other hand, when the air lift pump 20 is disposed outside the treatment tank 2, there is no gap, making it easier to replace the small wood chips.

[0044] In addition, in conventional devices in which the air lift pump is disposed inside the treatment tank, the lid 7 must be opened to clean the inside of the air lift pump, but the lid 7, which has approximately the same diameter as the diameter of the treatment tank 2, is heavy and places a burden on the work. On the other hand, in the wastewater treatment device 1 according to this embodiment in which the air lift pump 20 is disposed outside the treatment tank 2, the inside of the air lift pump 20 can be cleaned by opening the lid 31, which has a smaller diameter than the lid 7 that covers the top of the treatment tank 2, thereby reducing the workload.

[0045] (Cleaning piping) Fig. 3 is a diagram for explaining a schematic configuration of a wastewater treatment device 1 according to another embodiment. In the example shown in Fig. 3, a cleaning pipe 40 extending in the vertical direction is provided at the upper end of the lift pipe 22. The cleaning pipe 40 has a lower end connected to the upper end of the lift pipe 22 and an upper end located at the ground surface GL. An openable and closable lid 41 is attached to the upper end opening of the cleaning pipe 40.

[0046] In the wastewater treatment device 1 equipped with the above-mentioned cleaning pipe 40, when performing high-pressure cleaning inside the air lift pump 20, the lid 41 is opened and a high-pressure cleaning hose is inserted from the upper end of the cleaning pipe 40. By supplying high-pressure water in this state, the high-pressure water flows into the lift pipe 22, and the inside of the air lift pump 20 can be high-pressure cleaned.

[0047] 1, the upper end of the lift pipe 22 is located lower than the ground surface GL, so there is room for improvement in terms of ease of operation for a cleaning worker when opening the lid 30 or inserting a high-pressure cleaning hose into the upper end of the lift pipe 22. On the other hand, according to the wastewater treatment device 1 shown in FIG. 3, a cleaning pipe 40 is connected to the upper end of the lift pipe 22, and the upper end of the cleaning pipe 40 reaches the ground surface GL, so that the worker can easily open the lid 41 or insert a high-pressure cleaning hose into the cleaning pipe 40.

[0048] In the example shown in Fig. 3, the cleaning pipe 40 extends vertically, but as long as the lower end of the cleaning pipe 40 is connected to the upper end of the water lift pipe 22 and the upper end of the cleaning pipe 40 is located on the ground surface GL, the shape between the upper end and the lower end of the cleaning pipe 40 is not particularly limited. In addition, the upper end of the cleaning pipe 40 may be located above the ground surface GL.

[0049] In the above examples, the region above the crushed stone layer 5 was a topsoil layer 8 formed by backfilling a borehole, but it may be a concrete slab 50 as shown in Figures 4 and 5. Such a wastewater treatment device 1 is applied to a place where automobiles pass through, such as a parking lot.

[0050] Although the embodiment of the present invention has been exemplified above, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

[0051] For example, the components of the above-described embodiments may be combined in any manner. Any combination will naturally provide the functions and advantages of each of the components in the combination, and will also provide other functions and advantages that will be apparent to those skilled in the art from the description of this specification.

[0052] In addition, the effects described in this specification are merely explanatory or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that are apparent to a person skilled in the art from the description of this specification in addition to or in place of the above effects. [Industrial Applicability]

[0053] The present invention can be applied to wastewater treatment equipment that utilizes small wood chips. [Explanation of symbols]

[0054] 1 Wastewater treatment equipment 2 Treatment tank 3 Through holes 4. Concrete slab 5 Crushed Stone Layer 6 Adjuster 7 Lid 8 Topsoil layer 9 Wood chips layer 10 Water test tube 20 Air lift pump 21 Outer tube 22 Lift pipe 23 Air pipe 24 Blower 25 Water pipe 26 Sprinkler pipe 27 Drain pipe 28 Overflow pipe 29 cases 30 Lid 31 Lid 40 Cleaning piping 41 Lid 50 Concrete slab

Claims

1. A wastewater treatment device for purifying wastewater, A treatment tank that is partially or completely buried underground; A wood chip layer formed by accumulating wood chips in the treatment tank; an air lift pump disposed outside the treatment tank; a water supply pipe for supplying the wastewater to the wood chip layer, The treatment tank is configured to be water permeable from the inside to the outside, The air lift pump is A vertically extending outer cylinder pipe through which the drainage water is supplied; A lift pipe disposed inside the outer tube; and an air pipe for sending air into the water lift pipe, One end of the water supply pipe is connected to the water lift pipe, The wastewater treatment device, wherein the other end of the water supply pipe is located within the treatment tank.

2. A cleaning pipe is connected to an upper end of the lift pipe, The wastewater treatment device according to claim 1, wherein an upper end of the cleaning pipe is located at or above the ground level.

3. It has an overflow pipe with a check valve, one end of the overflow pipe is connected to the outer tube below a connection point of the water supply pipe to the outer tube, 3. The wastewater treatment device according to claim 1, wherein the other end of the overflow pipe is located within the treatment tank.

4. a drain pipe connected to the outer tube for supplying the drainage water; The overflow pipe is a first pipe line extending horizontally and connected to the outer pipe; a second pipeline extending downward from the first pipeline and having a lower end located within the treatment tank; The wastewater treatment device according to claim 3, wherein the pipe axis of the first pipe line is located below the position of the pipe axis of the drain pipe at a connection point between the outer tube and the drain pipe.

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