JP7576902B2 - Container-type trickling filter device and method for cleaning treated water tank in container-type trickling filter device - Google Patents

Description

The present invention relates to a trickling filter device in a wastewater purification system that purifies wastewater such as industrial wastewater, water supply and sewage, and river water. More specifically, the present invention relates to a container-type trickling filter device in which microorganisms are attached to a trickling filter bed in which filter media blocks (microorganism-holding carriers) are stacked in layers in a reaction tank, wastewater is sprayed over the trickling filter bed, and the treated water that has permeated and flowed down is removed from the treated water tank, and a method for cleaning the treated water tank in a container-type trickling filter device.

Trickling filters have long been used as a method for purifying wastewater.
A typical trickling filter device is composed of a reaction tank, a trickling device installed above the reaction tank, and a treated water tank that receives and stores the treated water that has passed through the reaction tank.The reaction tank is filled with microorganism-retaining carriers to which microorganisms contained in the wastewater are attached, and the collection of these microorganism-retaining carriers forms a trickling filter bed.
Wastewater is sprayed from above and flows from top to bottom within the reaction tank due to gravity. During this time, the water is purified and treated by the microorganism retention carriers and falls into the treatment tank below.
Such a trickling filter has the advantages of low power consumption, easy operation and management, and low sludge production.

As an example of a microorganism-holding carrier in the above-mentioned wastewater purification device, the applicant has applied for a water purification device configured to fill a reaction tank with sponge carriers, rain (sprinkle) treated water, take in air around the sponge carriers, and have the microorganisms in the carriers use the air to oxidize organic matter and ammonia in the wastewater, thereby purifying the wastewater (JP Patent Publication No. 2019-171237).

Depending on the location where the trickling filter device is installed, insects such as moth flies may appear, so the device is enclosed and air is supplied to the inside of the device by a fan to ventilate the inside. In a general structure, air is sucked in by a fan from below the reaction tank (20) to ventilate the inside of the device. This prevents the smell of wastewater from leaking directly from the trickling filter contained inside the device.
At the same time as the treated water, solid matter that has not been captured by the trickling filter falls into the treatment tank. If these solid matter falls into the treatment tank and remains there for a long time, it will rot and pollute the treated water, so the solid matter must be discharged.
In conventional trickling filter devices, the treated water tank below the trickling filter has a large volume and sufficient depth, and a certain amount of solid matter is accumulated, and the bottom of the treated water tank is sloped at about 20% to promote the discharge of solid matter, and the accumulated solid matter is discharged through a solid matter extraction pipe located near the bottom of the treated water tank.In addition, the solid matter is also scraped up with a scraper with a scraper, and discharged when a certain amount of solid matter has accumulated.

JP 2019-171237 A

Trickling bed devices, which have the advantages of low power consumption, easy operation and management, and low sludge generation, are expected to become more widespread in developing countries as environmental pollution problems become more serious. One possible way to popularize them is to incorporate them into marine transport containers and export them. Container-type trickling bed devices can be manufactured in domestic factories, transported by sea to the site, installed, and connected to pipes for wastewater, treated water, etc., so that they can be used quickly.
However, there are size restrictions for marine transport containers, and the device must be within the size restrictions. On the other hand, it is important to ensure a sufficient capacity of the trickling filter in order to ensure a sufficient amount of microorganisms in the trickling filter that contributes to the purification of wastewater. As mentioned above, in conventional trickling filter devices, the treatment tank below the trickling filter is large in volume and deep enough, but in order to incorporate the trickling filter device into a marine transport container with size restrictions, the slope of the bottom of the treatment tank cannot be sufficiently ensured to promote the discharge of solids. If the discharge is not promoted, measures to prevent the generation of bad odors due to the decay of solids are necessary. Furthermore, when a conventional scraper is installed, space for auxiliary equipment such as a drive unit must be secured.

The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a trickling filter device that can automatically discharge solids accumulated in the treatment tank below the trickling filter without using a scraping machine or the like, and that can be incorporated into a sea transport container which is subject to dimensional regulations.

The present inventors have achieved the above object by the following means.
[1] A trickling filter device (1) comprising a reaction tank (20), an inspection hatch (27) for inspecting the inside of the reaction tank (20), and a treated water tank (30), wherein the reaction tank (20) comprises an airtight rectangular parallelepiped housing (21), a mesh-like bottom plate (22) provided at the bottom of the housing (21), and a carrier (23) filled in the housing (21), and the treated water tank (30) comprises a box-shaped main body (30A) comprising an inclined rectangular bottom plate (31) having a gradient of at least 1/100 to 15/100 toward the discharge direction of the treated water, and side walls (32 to 35);
The system comprises a water tank section (36) provided in the treated water discharge direction of the main body (30A), a weir (37) provided in the water tank section (36), an air withdrawal pipe (38), a treated water withdrawal pipe (40), and a solid matter withdrawal pipe (41), and the water tank section (36) is configured to be horizontally outward of the trickling filter bed device (1).
A container-type trickling filter device characterized by the above.
[2] The container-type trickling filter apparatus according to [1], characterized in that a circulating treated water withdrawal pipe (42) is provided in the water tank section (36).
[3] A container-type trickling filter device as described in [2], characterized in that an overflow trough (43) is provided in the treated water tank (30), and a partition plate (44) is movably provided between the treated water withdrawal pipe (40) connected to the overflow trough (43) and the circulating treated water withdrawal pipe (42).
[4] A container-type trickling filter device as described in any one of [1] to [3], characterized in that a drain pipe (45) for discharging accumulated water from within the air extraction pipe (38) is provided midway through the air extraction pipe (38).
[5] A container-type trickling filter device described in any one of [1] to [4], characterized in that the air extraction pipe (38) is inclined so that the tip (38a) of the air extraction pipe (38) is downward.
[ 6 ] A container-type trickling filter device as described in any one of [1] to [5], characterized in that the treated water tank (30) of the trickling filter device (1) is used as a civil engineering structure, and the space occupied by the treated water tank (30) is replaced with and increased in capacity by the reaction tank ( 20 ) of the trickling filter device (1) within the dimensional regulations of marine transport containers.
[7] The container-type trickling bed device described in [6], characterized in that the reaction tank ( 20 ) is composed of multiple stages of the housings (21), and the height and volume of the trickling bed device (1) can be changed by changing the number of the housings (21).
[8] A method for cleaning the treated water tank (30) of a container-type trickling filter bed apparatus described in any one of [1] to [7], characterized in that when removing solids, the valve of the solids removal pipe (41) is opened to discharge the entire amount of treated water accumulated in the treated water tank (30), and while the wastewater is being sprayed onto the trickling filter bed, the treated water that passes through the filter bed and drips into the treated water tank (30) is showered to send the accumulated solids on the bottom plate ( 31 ) together with the treated water toward the weir (37) even at a gentle incline close to horizontal.

According to the present invention configured as above, in a container-type trickling filter device, it is possible to automatically discharge solids accumulated in the treatment tank without using machinery, etc., and to provide a trickling filter device that is incorporated in a sea transport container that is subject to dimensional regulations.

FIG. 1 is a perspective side view of an embodiment of a container-type trickling filter device of the present invention. FIG. 2 is a front view of an embodiment of the container-type trickling filter device of the present invention. FIG. 2 is a plan view of an embodiment of the container-type trickling filter device of the present invention. FIG. 2 is a side view of an embodiment of the container-type trickling filter device of the present invention. AA cross-sectional view of FIG. BB cross-sectional view of FIG. 4C-C cross-sectional view of FIG. FIG. 1 is a diagram showing another embodiment of the container-type trickling filter device of the present invention. FIG. 1 is a diagram showing another embodiment of the container-type trickling filter device of the present invention. FIG. 1 is a diagram showing another embodiment of the container-type trickling filter device of the present invention. FIG. 1 is a diagram showing another embodiment of the container-type trickling filter device of the present invention. FIG. 1 is a diagram showing another embodiment of the container-type trickling filter device of the present invention. FIG. 1 is a diagram showing another embodiment of the container-type trickling filter device of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is an oblique side view of an embodiment of a container-type trickling filter bed device of the present invention, an example in which a marine transport container is used as the outer frame, FIG. 2 is a front view of an embodiment of a container-type trickling filter bed device of the present invention, FIG. 3 is a plan view of an embodiment of a container-type trickling filter bed device of the present invention, FIG. 4 is a side view of an embodiment of a container-type trickling filter bed device of the present invention, FIG. 5 is a cross-sectional view A-A of FIG. 3, FIG. 6 is a cross-sectional view B-B of FIG. 4, FIG. 7 is a cross-sectional view C-C of FIG. 4, and FIGS. 8 and 9 are diagrams showing other embodiments of a container-type trickling filter bed device of the present invention.
In Figures 1 to 11, reference numeral 1 denotes a trickling filter device, 20 denotes a reaction tank, and 30 denotes a treated water tank.
In the embodiment of the present invention, the frames (51-54) of containers for marine transport are used in consideration of the marine transportation of the container-type trickling filter device, but the present invention is not limited to this. A feature of the present invention is that the container-type trickling filter device can reduce the size of the treated water tank 30 and discharge treated water and solids without using machinery such as a scraper.
The reaction tank 20 is made of an airtight rectangular parallelepiped housing 21, and a mesh-like bottom plate 22 is provided on the bottom of the housing 21 along the horizontal direction.
A sponge carrier 23 (sometimes referred to as carrier 23 in the present invention) is filled on top of the bottom plate 22 and is made of a porous material with an open-cell structure that has water retention and flexibility.
As shown in FIG. 11, in this embodiment, the sponge carrier 23 is composed of a porous body 24 having gaps to which microorganisms can adhere, and a frame 25 for housing the porous body 24.
Specifically, the material for the porous body 24 is a porous body obtained by foaming a resin such as a urethane resin, an ester polymer, or an ether polymer.
Wastewater is sprayed from a spray nozzle (not shown) provided at the top of the trickling filter device onto the sponge carrier 23 inside the housing 21. The sprayed wastewater moves downward by penetrating the porous body 24 of the sponge carrier 23 or passing over the surface of the porous body 24, during which the wastewater is purified by the microorganisms attached to the porous body 24 and drips from the bottom of the trickling filter as treated water.
At this time, the liquid penetrates into the porous body 24 through the openings 25a provided in the frame 25, and oxygen and other substances dissolved in the liquid from the pollutants in the liquid and the air supplied to the gaps between the carriers are efficiently supplied to the microorganisms present inside the porous body 24, thereby purifying the wastewater.
Reference numeral 26 denotes a space for connecting pipes and a ladder used for moving to the top of the equipment for inspection work, and reference numeral 27 denotes an inspection hatch for inspecting the inside of the reaction tank.
As described later, when air is drawn into the treatment tank 30 by a fan or the like (not shown) through an air extraction pipe 38 provided in the treatment tank 30, the liquid containing dissolved oxygen permeates through the surface of the sponge carrier 23 in the housing 21 of the reaction tank 20, and supplies oxygen and the like to the sponge carrier 23 in the housing 21 of the reaction tank 20. Although sponge is taken up here as a suitable example of a carrier, it is not necessary to use a carrier 23 using sponge as the material for the porous body 24. For example, stone or hard resin generally used as a filter material for water treatment may be used instead of the carrier 23.

The treated water tank 30 comprises a box-shaped main body 30A having a rectangular bottom plate 31 and side walls 32 to 35, and separates the treated water discharged from the reaction tank 20 and solids such as sludge.
The treated water tank 30 is provided with a water tank section 36 for collecting and discharging the treated water and solids such as sludge discharged from the reaction tank 20.
Moreover, since solid matter contained in the treated water is discharged into the treatment water tank 30 in addition to the purified treated water, the inclination of the bottom plate 31 must be such that the treated water and solid matter discharged into the treatment water tank 30 slide over the bottom plate 31 under their own weight and are sent from the side wall 33 toward the water tank section 36. However, if the inclination angle of the bottom plate 31 is large, it will be necessary to increase the height of the treatment water tank 30, which may result in restrictions on dimensions of containers for marine transport. Considering the need to keep the height of the treatment tank 30 down, it is preferable that the bottom plate 31 be horizontal and not inclined, but since the weight of the fixed objects would prevent them from being sent toward the weir 37, when removing the solids, the valve (not shown) of the solids removal pipe 41 is opened to discharge the entire amount of treated water accumulated in the treatment tank 30, and then, while the wastewater is being sprayed onto the trickling filter bed, the treated water that has passed through the filter bed and dripped into the treatment tank 30 is showered, so that the solids accumulated on the bottom plate 31 can be sent together with the treated water toward the weir 37 at a gentle incline close to horizontal. When there are no more solids on the bottom plate 31, the valve of the solids removal pipe 41 is closed and the treated water is stored in the treatment tank 30.
Considering these, the inclination angle is preferably 1/100 to 15/100, and more preferably 5/100 to 10/100.
If the inclination angle is less than 1/100, the solid objects are likely to accumulate on the bottom plate 31 instead of being sent toward the weir 37 by showering with the treated water dripping into the treated water tank 30 .
Furthermore, if the inclination angle exceeds 15/100, the height of the treatment tank 30 becomes large, and in order to incorporate the trickling filter device 1 within the dimensions regulated for marine transport containers, it is necessary to lower the height of the trickling filter reaction tank (20), which reduces the reaction tank capacity and reduces the purification capacity. For example, the external dimensions of a 10-foot marine transport container are 2,991 mm long x 2,438 mm wide x 2,591 mm high, and the height must be kept within 2,591 mm. The height is also regulated at 2,591 mm for 12-, 20-, and 40-foot types.

The water tank section 36 is provided with a dam 37 that holds back the treated water accumulated in the treatment water tank 30, and during normal operation, the treated water that slips under the dam 37 flows into the water tank section 36 and is discharged from the treated water withdrawal pipe 40.
In addition, the water tank section 36 is provided with an air extraction pipe 38 for extracting air from within the treatment water tank 30 .
The tip 38 a of the air extraction pipe 38 is provided so as to be above the water surface 39 of the treatment water stored in the water tank section 36 .
Since the area below tip 38a is sealed with treated water in this manner, when air is drawn in using a fan (not shown) or the like, the air passes through reaction tank 20 from the top and enters air extraction pipe 38, and at the same time, the putrid odor within treatment water tank 30 is expelled.
As described above, when air is drawn in through the air extraction pipe 38, air enters the air extraction pipe 38 from the top of the reaction tank 20, and at the same time, air etc. is supplied to the sponge carrier 23 inside the casing 21 of the reaction tank 20.

The water tank section 36 is provided with a solid matter extraction pipe 41 for extracting the treated water and solid matter accumulated in the water tank section 36 .
The solids extraction pipe 41 is provided to extract solids that accumulate on the inclined portion of the bottom plate 31 during operation of the container-type trickling filter device together with the treated water.
In the container-type trickling bed device 1 of this invention configured as described above, during operation of the trickling bed device, solids accumulated on the inclined portion of the bottom plate 31 are extracted together with the treated water by the solids extraction pipe 41, and when the treated water in the treated water tank 30 becomes empty, the treated water is dripped and sprinkled from above the reaction tank 20, falling like rain, so that any solids accumulated on the bottom plate 31 that could not be completely discharged when the treated water was extracted can be thoroughly washed away.
As described above, the container-type trickling filter device of the present invention does not require the installation of a mechanical discharge device such as a scraper as in the conventional method, so that solids do not accumulate when they are pulled out, and the inside of the treatment tank can be cleaned thoroughly and the accumulated solids can be discharged.

In the container-type trickling filter device 1 in this embodiment, the water tank section 36 that collects and discharges treated water and solids such as sludge in the lower treated water tank 30 is configured to be horizontally outside the container-type trickling filter device 1. This is because the structure has sufficient space to secure the space for the inspection hatch 27 for inspecting the inside of the reaction tank and the ladder 26 that is moved toward the top of the device and used for inspection work. As another embodiment, as shown in Figure 8, the reaction tank capacity may be increased, and the inspection hatch 27 for inspecting the inside of the reaction tank and the ladder 26 for inspection work may be configured to fit within the dimensional regulations of marine transport containers, and the water tank section 36 may be configured to be horizontally inside the container-type trickling filter device 1 to maximize the performance of the container-type trickling filter.

In FIG. 6, an embodiment is shown in which a treated water withdrawal pipe for circulation 42 is provided to circulate treated water to the piping on the wastewater supply side of the container-type trickling filter device 1 by a pump (not shown) in order to remove nitrogen from the wastewater. Ammonia in the wastewater is nitrified in the aerobic reaction tank 20, and treated water containing nitrate nitrogen is circulated to the reaction tank 20, where nitrogen is removed by denitrification reaction caused by the action of denitrifying bacteria, which are facultative anaerobic bacteria present in the reaction tank 20. The treated water withdrawal pipe 40 and the treated water withdrawal pipe for circulation 42 are connected to the overflow trough 43, and a partition plate 44 is movably installed between the treated water withdrawal pipe 40 and the treated water withdrawal pipe for circulation 42 of the overflow trough 43. The installation position of the partition plate 44 can be adjusted in the direction of the arrow in the figure in order to determine the amount of treated water to be circulated for circulation. That is, when the nitrogen removal rate needs to be increased, the partition plate 44 is moved closer to the treated water withdrawal pipe 40 side to increase the amount of treated water to be circulated. Conversely, when there is no need to increase the nitrogen removal rate, the partition plate 44 is moved closer to the circulating treated water withdrawal pipe 42 to reduce the amount of circulating treated water.

Figure 9 shows another embodiment of the container-type trickling filter device 1 of the present invention. When the inside of the air extraction pipe 38 becomes wet and condenses, water pools form, and if a fan or other device (not shown) is used to suck in the water, the fan may be damaged. Therefore, a drain pipe 45 is provided midway through the air extraction pipe 38, and the water pool in the air extraction pipe 38 is discharged to the treated water extraction pipe 40. The discharge destination is not limited to the treated water extraction pipe 40, but may be the solids extraction pipe 41, or the drain pipe 45 may be connected to the side wall 32 of the water tank section 36 by drilling a hole in the pipe.

Figure 10 shows another embodiment of the container-type trickling filter device 1 of the present invention, in which the air extraction pipe 38 is inclined so that the tip 38a of the air extraction pipe 38 is downward. This allows dew water generated in the air extraction pipe 38 to be discharged into the treated water tank 30, preventing water from pooling in the air extraction pipe 38.

11 to 13 are diagrams showing another embodiment of the container-type trickling filter device of the present invention.
FIG. 11 is a diagram showing the configuration of the reaction tank 20.
In Fig. 12, an embodiment is shown in which the treated water tank 30 of the container-type trickling filter device 1 shown in Fig. 1 is made of a civil engineering structure such as concrete. In this example, the space occupied by the treated water tank 30 in Fig. 1 can be replaced with the capacity of the reaction tank 20 of the container-type trickling filter device 1 within the dimensional regulations of marine transport containers, and can be increased. In addition, since it is possible to discharge the deposits on the gently sloping bottom plate 31 by showering, the height of the container-type trickling filter device 1 can be reduced, which has the advantage of making it compact. Therefore, while improving the purification capacity by increasing the capacity of the container-type trickling filter device 1, the space in the height direction of the container-type trickling filter device 1 can be reduced.

In Figure 13, as in Figure 12, the treatment tank 30 is an example in which a civil engineering structure is used, and the reaction tanks 20 are stacked in two layers.

As shown in Figures 12 and 13, the reaction tank 20 is composed of multiple housings 21, and the height and volume of the container-type trickling filter device 1 can be changed by increasing the number of housings 21 horizontally or changing the number of housings 21 vertically.

In the embodiment of the present invention, a marine transport container is used for the outer frame (51-54) of the container-type trickling filter device, but this is not limited to this, and the feature of the present invention is the structure of the treated water tank at the bottom of the container-type trickling filter device.

1: Container-type trickling filter device 20: Reaction tank 21: Housing 22: Bottom plate 23: Sponge carrier 26: Ladder 27: Inspection hatch 30: Treated water tank 31A: Main body 31: Bottom plate 32-35: Side wall 36: Water tank section 37: Weir 38: Air extraction pipe 40: Treated water extraction pipe 41: Solids extraction pipe 42: Circulating treated water extraction pipe 43: Overflow trough 44: Partition plate 45: Drain pipe 50: Civil engineering structure

Claims (8)

A trickling filter device (1) comprising a reaction tank (20), an inspection hatch (27) for inspecting the inside of the reaction tank (20) , and a treated water tank (30), wherein the reaction tank (20) comprises an airtight rectangular parallelepiped housing (21), a mesh-like bottom plate (22) provided at the bottom of the housing (21), and a carrier (23) filled in the housing (21), and the treated water tank (30) comprises a box-shaped main body (30A) comprising an inclined rectangular bottom plate (31) having a gradient of at least 1/100 to 15/100 toward the discharge direction of the treated water, and side walls (32 to 35);
The system comprises a water tank section (36) provided in the treated water discharge direction of the main body (30A), a weir (37) provided in the water tank section (36), an air withdrawal pipe (38), a treated water withdrawal pipe (40), and a solid matter withdrawal pipe (41), and the water tank section (36) is configured to be horizontally outward of the trickling filter bed device (1).
A container-type trickling filter device characterized by the above. The container-type trickling filter device according to claim 1, characterized in that a circulating treated water withdrawal pipe (42) is provided in the water tank section (36). The container-type trickling filter device according to claim 2, characterized in that an overflow trough (43) is provided in the treated water tank (30), and a partition plate (44) is movably provided between the treated water withdrawal pipe (40) connected to the overflow trough (43) and the circulating treated water withdrawal pipe (42). A container-type trickling filter device according to any one of claims 1 to 3, characterized in that a drain pipe (45) for discharging water from within the air extraction pipe (38) is provided midway along the air extraction pipe (38). A container-type trickling filter device according to any one of claims 1 to 4, characterized in that the air extraction pipe (38) is inclined so that the tip (38a) of the air extraction pipe (38) is downward. A container-type trickling filter device as described in any one of claims 1 to 5, characterized in that the treated water tank (30) of the trickling filter device (1) is made into a civil engineering structure, and the space occupied by the treated water tank (30) is replaced and increased by the capacity of the reaction tank (20 ) of the trickling filter device (1) within the dimensional regulations of marine transport containers. The container-type trickling bed device according to claim 6, characterized in that the reaction tank (20) is composed of a plurality of stages of the housings (21), and the height and volume of the trickling bed device (1) are changed by changing the number of the housings ( 21 ). A method for cleaning the treated water tank (30) of a container-type trickling filter apparatus as described in any one of claims 1 to 7, characterized in that when removing solids, the valve of the solids removal pipe (41) is opened to discharge the entire amount of treated water accumulated in the treated water tank (30), and then, while the wastewater is being sprayed onto the trickling filter bed, the treated water that passes through the filter bed and drips into the treated water tank (30) is showered to send the accumulated solids on the bottom plate (31) together with the treated water toward the weir ( 37 ) even at a gentle incline close to horizontal.

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