JP6976556B2 - Wastewater treatment equipment - Google Patents

Description

The present specification relates to wastewater treatment utilizing microorganisms.

Traditionally, wastewater treatment has been performed using microorganisms. As a wastewater treatment device for performing such wastewater treatment, for example, a device including a settling separation tank and a contact aeration tank connected to the downstream side of the settling separation tank is used. Here, a technique has been proposed in which an advection port is provided at the height of the liquid level on the partition wall that separates the settling separation tank and the contact aeration tank. The exfoliated sludge floating on the liquid surface of the contact aeration tank can be returned to the settling separation tank through the opening.

Jitsufuku No. 6-28239

However, the fact is that sufficient measures have not been taken to promote the transfer of solid matter to another treatment tank.

The present specification discloses techniques that can facilitate the transfer of solids to another treatment tank.

The present specification discloses, for example, the following application examples.

[Application Example 1]
It is a wastewater treatment device
A plurality of treatment tanks including an anaerobic treatment tank and an aerobic treatment tank provided on the downstream side of the anaerobic treatment tank.
A partition wall separating the anaerobic treatment tank and the aerobic treatment tank,
The air diffuser provided in the aerobic treatment tank and
A transfer pump that transfers the water in the anaerobic treatment tank to another treatment tank different from the anaerobic treatment tank and the aerobic treatment tank among the plurality of treatment tanks.
An advection opening forming portion provided on the downstream side of the aerobic treatment tank and forming an advection opening for transferring water to the downstream side.
Equipped with
The partition wall is a plurality of openings communicating the anaerobic treatment tank and the aerobic treatment tank, and has a plurality of openings including one or more first openings and one or more second openings.
Each of the one or more first openings has a lower end arranged at a position lower than a predetermined reference water level and an upper end arranged at a position higher than the reference water level.
The first or more second openings are
A low opening which is a position at a height below the reference water level and has an upper end arranged at a position lower than any of the upper ends of each of the above-mentioned first openings.
The width of the opening at the height of the reference water level is the height of the reference water level, extending from a position lower than any of the lower ends of each of the first or more first openings to a position higher than the reference water level. A narrow opening, which is an opening smaller than any of the widths of each of the above-mentioned one or more first openings in the above.
Including at least one of
The anaerobic treatment tank
A portion of the anaerobic treatment tank located at a position lower than the lowest end of the lower end of each of the one or more first openings and the lower end of each of the first or more second openings. A baffle that forms a third opening including the third opening and communicates the third opening with the first opening and the second opening.
The introduction section for guiding the water flowing into the anaerobic treatment tank to the anaerobic treatment tank, wherein the lower end of the introduction section is arranged at a position higher than the upper end of the third opening.
Equipped with
The transfer pump has a suction port including a portion located at a position lower than the lowermost end.
The size of the advection opening is such that the advection opening is transferred when the amount of water flowing into the wastewater treatment apparatus per unit time is temporarily increased by the peak inflow preliminarily associated with the wastewater treatment apparatus. The water level between the anaerobic treatment tank and the aerobic treatment tank is temporarily raised by limiting the amount of water to be applied per unit time to a smaller amount than the amount of the peak inflow per unit time. Has been,
Wastewater treatment equipment.

According to this configuration, in the aerobic treatment tank, an upward water flow is generated by the air diffuser by the air diffuser. When the water flowing upward reaches the surface of the water, it moves horizontally along the surface of the water. Since the lower end of the first opening is arranged at a position lower than the reference water level and the upper end of the first opening is arranged at a position higher than the reference water level, the water flowing along the water surface is arranged at the first opening. Can flow into the anaerobic treatment tank through. Further, one or more second openings are "openings having an upper end located at a position at a height below the reference water level and lower than any of the upper ends of each of the first or more first openings." The width of the opening at the height of the reference water level is the height of the reference water level. It includes at least one of "a narrow opening, which is an opening smaller than any of the widths of one or more first openings in." Therefore, the water flowing along the water surface is less likely to move from the second opening to the anaerobic treatment tank as compared with the first opening. This can result in a cycle in which water flows from the aerobic treatment tank to the anaerobic treatment tank through the first opening and then from the anaerobic treatment tank to the aerobic treatment tank through the second opening. Due to such a flow of water, the solid matter in the aerobic treatment tank can move from the aerobic treatment tank to the anaerobic treatment tank through the first opening. In the anaerobic treatment tank, the flow of water is slower than that of the aerobic treatment tank in which air is dispersed. Can precipitate in. In this way, it is possible to promote the movement of the solid matter from the aerobic treatment tank to the anaerobic treatment tank through the first opening. Then, it is possible to suppress an increase in the amount of solid matter in the aerobic treatment tank.
Further, in the anaerobic treatment tank, water flows downward from the introduction portion to the third opening, and then flows upward in the baffle from the third opening to the first opening and the second opening. Therefore, the anaerobic treatment tank can store the sludge generated in the anaerobic treatment tank at the bottom of the anaerobic treatment tank. Then, in the anaerobic treatment tank, the solid matter transferred from the aerobic treatment tank to the anaerobic treatment tank through the first opening can also be stored in the bottom of the anaerobic treatment tank.
In addition, the water level in the anaerobic treatment tank rises temporarily during the peak inflow. Therefore, the amount of transfer from the anaerobic treatment tank to another treatment tank by the transfer pump can be temporarily increased. As a result, when the solid matter moves from the aerobic treatment tank to the anaerobic treatment tank through the first opening, it is possible to suppress an increase in the amount of the solid matter in the anaerobic treatment tank.

[Application example 2]
The wastewater treatment apparatus according to Application Example 1.
The transfer pump is an air lift pump.
Wastewater treatment equipment.

According to this configuration, when the water level of the anaerobic treatment tank rises temporarily, the amount of transfer from the anaerobic treatment tank to another treatment tank by the transfer pump can be appropriately increased. As a result, when the solid matter moves from the aerobic treatment tank to the anaerobic treatment tank through the first opening, it is possible to suppress an increase in the amount of the solid matter in the anaerobic treatment tank.

[Application example 3]
The wastewater treatment apparatus according to Application Example 1 or 2.
The one or more first openings include one or more openings having an upper end located above the reference water level.
The one or more second openings include one or more openings having an upper end located below the reference water level.
Wastewater treatment equipment.

According to this configuration, the movement of solid matter through the first opening can be further promoted. In addition, it is possible to appropriately suppress an increase in the amount of solid matter in the aerobic treatment tank.

[Application example 4]
The wastewater treatment apparatus according to any one of Application Examples 1 to 3.
The shape of each of the one or more specific first openings of the one or more first openings and the shape of each of the one or more specific second openings of the one or more second openings are the same. It has a circular shape with an inner diameter,
Each center of the one or more specific second openings is located lower than any of the centers of the one or more specific first openings.
Wastewater treatment equipment.

According to this configuration, the first opening and the second opening that can promote the movement of the solid matter through the first opening can be easily formed.

[Application Example 5]
The wastewater treatment apparatus according to any one of Application Examples 1 to 4.
The plurality of openings include one or more water level openings that are openings having a lower end arranged at a position lower than the reference water level and an upper end arranged at a position higher than the reference water level.
The one or more first openings are one or more openings having the widest opening width at the height of the reference water level among the one or more water level openings.
Wastewater treatment equipment.

According to this configuration, the solid matter can be appropriately transferred by using the first opening and the second opening.

[Application example 6]
The wastewater treatment apparatus according to any one of Application Examples 1 to 5.
The plurality of treatment tanks include a downstream treatment tank which is a treatment tank on the downstream side of the aerobic treatment tank.
When the transfer pump is referred to as a first transfer pump, the wastewater treatment device is used.
A communication portion that communicates the aerobic treatment tank and the downstream treatment tank, and includes a portion that forms a flow path lower than the lowermost end.
A second transfer pump that transfers the water in the downstream treatment tank to another treatment tank different from the anaerobic treatment tank, the aerobic treatment tank, and the downstream treatment tank among the plurality of treatment tanks.
Equipped with a wastewater treatment device.

According to this configuration, the solid matter that has moved to a position lower than the first opening and the second opening in the aerobic treatment tank can move to the downstream treatment tank. Then, the solid matter in the downstream processing tank can be transferred to another processing tank by the second transfer pump. In this way, the solid matter in the aerobic treatment tank is transferred to another treatment tank through the downstream treatment tank and the second transfer pump, so that the amount of solid matter in the aerobic treatment tank increases. Can be suppressed.

The technique disclosed in the present specification can be realized in various embodiments, for example, in the form of a wastewater treatment device, a wastewater treatment system having the wastewater treatment device and a blower, and the like. can.

It is explanatory drawing which shows the schematic structure of the wastewater treatment system 900. It is a schematic diagram of the wastewater treatment apparatus 800 viewed sideways. It is a schematic diagram of the wastewater treatment apparatus 800 viewed downward, and is a schematic diagram of a gas flow path. It is a schematic diagram of the wastewater treatment apparatus 800 seen from the VV cross section in FIG. 3A facing the contact filter bed tank 830 side. It is explanatory drawing of the mechanism of sludge transfer. It is a schematic diagram of the test tank 1000. It is a graph which shows the test result. It is explanatory drawing of the mechanism of transfer of solid matter. It is a graph which shows the example of the fluctuation of the water level WL at the time of the peak inflow. It is a table which shows the result of the simulation of the fluctuation of the water level WL. It is a schematic diagram which shows the modification of the opening 200, 300. It is a schematic diagram which shows the modification of the opening.

A. First Example:
A1. Configuration of wastewater treatment device 800:
FIG. 1 is an explanatory diagram showing a schematic configuration of a wastewater treatment system 900. The wastewater treatment system 900 includes a wastewater treatment device 800 and a blower 500 connected to the wastewater treatment device 800. The wastewater treatment device 800 of this embodiment purifies wastewater (also referred to as raw water) from ordinary households and the like (such a device is also referred to as a “separation tank”). The wastewater treatment device 800 has a settling separation tank 810, an anaerobic filter bed tank 820, a contact filter bed tank 830, and a treatment water tank 840 in order from the upstream side (left side in FIG. 1) in order to perform purification treatment through a plurality of steps. , Has a disinfection tank 850. The wastewater flowing into the wastewater treatment device 800 through the inflow port 802 is sequentially treated in the settling separation tank 810, the anaerobic filter bed tank 820, the contact filter bed tank 830, the treatment water tank 840, and the disinfection tank 850, and then drained through the discharge port 804. It is discharged to the outside of the processing device 800. Hereinafter, the water flowing through each water treatment tank is referred to as "water to be treated" or simply "water". The blower 500 supplies a gas containing oxygen (here, air) to the wastewater treatment apparatus 800. The wastewater treatment device 800 uses the gas from the blower 500 to proceed with the purification treatment.

FIG. 2 is a schematic view of the wastewater treatment apparatus 800 viewed sideways. FIG. 3A is a schematic view of the wastewater treatment apparatus 800 viewed downward. In these figures, the low water level LWL and the high water level HWL are water levels that are associated with the wastewater treatment apparatus 800 in advance and serve as a reference for operation. The low water level LWL and the high water level HWL are predetermined for each model of the wastewater treatment device. In this embodiment, the water in the treated water tank 840 is transferred to the disinfection tank 850 through the advection opening 852 provided in the disinfection tank 850 described later. The low water level LWL is the water level at the lower end of the advection opening 852. The low water level LWL indicates a stable water level in a state where the wastewater treatment device 800 operates normally and there is no inflow of wastewater into the wastewater treatment device 800 (hereinafter, the low water level LWL is also referred to as a reference water level LWL). .. Further, the high water level HWL is the water level at the lower end of the overflow opening 854 provided in the disinfection tank 850 described later. The overflow opening 854 is arranged at a position higher than the advection opening 852. When the amount of inflow water into the wastewater treatment device 800 per unit time is large, the water level WL gradually increases from the low water level LWL. Then, when the water level WL reaches the high water level HWL, the water in the treated water tank 840 is transferred to the disinfection tank 850 through the advection opening 854 in addition to the advection opening 852. As a result, it is suppressed that the water level WL becomes higher than the high water level HWL. When the inflow of wastewater into the wastewater treatment device 800 is stopped, the water level WL drops to the low water level LWL.

Further, the Z direction indicates a direction from the lower side to the upper side in the vertical direction, the X direction indicates the longitudinal direction (horizontal direction) of the wastewater treatment device 800, and the Y direction indicates the X direction and the Z direction, respectively. Indicates the orthogonal direction (horizontal direction). Hereinafter, the side in the X direction is also referred to as "+ X side", and the side in the opposite direction to the X direction is also referred to as "-X side". The same applies to the Y direction and the Z direction. FIG. 2 is a schematic view of the wastewater treatment apparatus 800 as viewed in the Y direction perpendicular to the longitudinal direction.

The settling separation tank 810 (FIG. 1) is a water treatment tank that separates solid matter in wastewater. The settling separation tank 810 is provided with an inflow baffle 812 (FIGS. 2 and 3 (A)). On the + X side of the settling separation tank 810, a partition wall 819 that separates the settling separation tank 810 and the anaerobic filter bed tank 820 is provided. In this embodiment, the partition wall 819 is connected to the outer wall 801 (also referred to as the tank body 801) of the wastewater treatment device 800, and the internal space formed by the tank body 801 (particularly, the portion having a high water level HWL or less) is formed. , It is divided into two parts perpendicular to the X direction. The partition wall 819 is formed with an advection opening 814 that communicates the settling separation tank 810 and the anaerobic filter bed tank 820. In this embodiment, the advection opening 814 is lower than the reference water level LWL, and the shortest distance between the advection opening 814 and the reference water level LWL is smaller than the shortest distance between the advection opening 814 and the bottom of the settling separation tank 810. It is formed at the position.

In this embodiment, the inflow baffle 812 is a box-shaped processing portion having a closed bottom and an opening 811 on the side surface. The drainage from the inflow port 802 (also called sewage) flows into the inflow baffle 812. The water flowing into the inflow baffle 812 moves to the inside of the settling separation tank 810 through the opening 811 and flows to the anaerobic filter bed tank 820 through the advection opening 814. While the water moves from the opening 811 of the inflow baffle 812 to the advection opening 814, the solids contained in the water settle to the bottom of the settling separation tank 810 and are separated. The settled solid matter is deposited and stored at the bottom of the settling separation tank 810 (also called sedimentary sludge). Further, since the opening 811 of the inflow baffle 812 is formed on the side surface of the inflow baffle 812 instead of the bottom, water flows out from the opening 811 in a direction close to horizontal rather than downward. As a result, it is possible to prevent the solid matter settled at the bottom of the settling separation tank 810 from being unintentionally rolled up by the water flow from the opening 811. However, the opening 811 of the inflow baffle 812 may be provided at the bottom of the inflow baffle 812.

The anaerobic filter bed tank 820 (FIG. 1) is a water treatment tank that performs anaerobic treatment with anaerobic microorganisms. As shown in FIGS. 2 and 3A, the anaerobic filter bed tank 820 is provided with a filter medium 826 and an advection baffle 823. Anaerobic microorganisms may adhere to the filter medium 826. The anaerobic treatment proceeds by the anaerobic microorganisms attached to the filter medium 826. The filter medium 826 is arranged at a position higher than the bottom of the anaerobic filter bed tank 820 and lower than the advection opening 814. As the filter medium 826, various members capable of retaining microorganisms, such as a member including a net-like portion and a member including a plate-like portion, can be adopted.

On the + X side of the anaerobic filter bed tank 820, a partition wall 829 that separates the anaerobic filter bed tank 820 and the contact filter bed tank 830 is provided. In this embodiment, the partition wall 829 is connected to the tank body 801 and divides the internal space of the tank body 801 (particularly, the portion below the high water level HWL) into two perpendicular to the X direction. There is.

The advection baffle 823 is fixed to the surface of the partition wall 829 on the anaerobic filter bed tank 820 side (here, the surface on the −X side). As shown in FIG. 3A, the horizontal (that is, perpendicular to the Z direction) cross-sectional shape of the advection baffle 823 is a substantially U-shape convex toward the −X side. As shown in FIG. 2, the advection baffle 823 is located at a position lower than the reference water level LWL (specifically, at a height of 826b or less at the lower end of the filter medium 826 and higher than the bottom of the anaerobic filter bed tank 820). It is an arch-shaped member extending in the Z direction to a position higher than the high water level HWL. The −Z end of the advection baffle 823 forms a lower opening 824, and the + Z end of the advection baffle 823 is provided on the + Z side of the high water level HWL. The anaerobic filter bed tank 820 is divided into a first portion 821, which is an outer portion of the advection baffle 823, and a second portion 822, which is an inner portion of the advection baffle 823. The filter medium 826 is provided in the first portion 821.

The partition wall 829 is formed with openings 200 and 300 for communicating the anaerobic filter bed tank 820 and the contact filter bed tank 830. In this embodiment, the openings 200 and 300 are formed in the portion of the partition wall 829 covered with the advection baffle 823, and communicate the second portion 822 of the anaerobic filter bed tank 820 with the contact filter bed tank 830. do.

As shown in FIG. 2, the water flowing into the anaerobic filter bed tank 820 from the advection opening 814 flows downward through the first portion 821 having the filter media 826, and from the lower opening 824 to the second portion of the advection baffle 823. It moves to 822, flows upward through the second portion 822, and is advected to the contact filter bed tank 830 through openings 200, 300.

In the anaerobic filter bed tank 820, organic substances in the water to be treated are decomposed by the anaerobic treatment by the anaerobic microorganisms adhering to the filter medium 826. Further, as will be described later, in the anaerobic filter bed tank 820, water (water containing nitrate ions (also referred to as nitrification solution)) that has been aerobically treated in the contact filter bed tank 830 is circulated to the air lift pump 920 and the settling separation tank. It flows in through 810. In the anaerobic filter bed tank 820, nitrate ions are reduced to generate nitrogen gas by the action of denitrifying bacteria contained in anaerobic microorganisms, and the generated nitrogen gas is released into the air (so-called denitrification). In addition, the filter medium 826 can capture suspended matter in the water to be treated.

As shown in FIGS. 2 and 3A, a sludge transfer air lift pump 910 is provided in the advection baffle 823. As shown in FIG. 2, the suction port 911 of the sludge transfer air lift pump 910 is located at a position lower than the lower opening 824 of the advection baffle 823 and higher than the bottom of the anaerobic filter bed tank 820, that is, the bottom of the anaerobic filter bed tank 820 (that is, the bottom of the anaerobic filter bed tank 820. In this embodiment, it is arranged at a position lower than the lower end 826b of the filter medium 826). The outlet 912 of the sludge transfer air lift pump 910 is arranged above the settling separation tank 810 (above the inflow baffle 812 in this embodiment). Gas from the blower 500 is supplied to the sludge transfer air lift pump 910. The sludge transfer air lift pump 910 can transfer the solid matter (for example, sludge) deposited on the bottom of the anaerobic filter bed tank 820 to the settling separation tank 810 by using the gas from the blower 500.

The contact filter bed tank 830 (FIG. 1) is a water treatment tank that performs aerobic treatment with aerobic microorganisms. As shown in FIGS. 2 and 3A, the contact filter bed tank 830 is provided with a contact material 836 and air diffusers 838a and 838b.

The contact material 836 is arranged at a position higher than the bottom of the contact filter bed tank 830 and lower than the openings 200 and 300. The air diffusers 838a and 838b are arranged below the contact material 832. As shown in FIG. 3A, the first air diffuser 838a is arranged on the + Y side of the contact filter bed tank 830, and the second air diffuser 838b is arranged on the −Y side of the contact filter bed tank 830. ing. Each of these air diffusers 838a and 838b is formed of a pipe having a plurality of through holes formed on the lower surface thereof. Gas containing oxygen from the blower 500 is supplied to the air diffusers 838a and 838b. The oxygen-containing gas is discharged into the water through the plurality of through holes of the air diffuser 838a and 838b. A large number of bubbles due to the discharged gas pass through the inside of the contact material 836 and reach the water surface of the water level WL (hereinafter, also referred to as the water surface WL). The movement of air bubbles creates a water flow, and the water in the contact filter bed tank 830 is agitated. In addition, aerobic microorganisms are retained in the contact material 836. Aerobic microorganisms use oxygen contained in bubbles to perform aerobic treatment. For example, aerobic microorganisms decompose organic matter in the water to be treated. In addition, the action of nitrifying bacteria contained in aerobic microorganisms oxidizes ammonium ions contained in the water to be treated to generate nitrite ions and nitrate ions (nitrification). The water containing nitrate ions (nitrification liquid) is transferred to the settling separation tank 810 by the circulation air lift pump 920 described later. As the contact material 836, various members capable of retaining microorganisms, such as a member including a net-like portion and a member including a plate-like portion, can be adopted.

On the + X side of the contact filter bed tank 830, a partition wall 839 that separates the contact filter bed tank 830 and the treatment water tank 840 is provided. In this embodiment, the partition wall 839 is connected to the tank body 801 and divides the internal space of the tank body 801 (particularly, the portion below the high water level HWL) into two perpendicular to the X direction. There is. As shown in FIG. 2, at least a part of the lower end of the partition wall 839 is arranged at a position away from the bottom of the tank body 801 on the + Z side to form an advection opening 834. The advection opening 834 communicates the contact filter bed tank 830 and the treatment water tank 840.

The water flowing into the contact filter bed tank 830 from the openings 200 and 300 is aerobically treated in the contact filter bed tank 830 and then transferred to the treatment water tank 840 through the advection opening 834.

The treatment water tank 840 (FIG. 1) is a water treatment tank that temporarily retains the water advected from the contact filter bed tank 830 to settle and separate solid matter (for example, sludge, suspended solids, etc.) in the water. As shown in FIG. 2, a disinfection tank 850 is arranged above the treatment water tank 840. The disinfection tank 850 is a treatment tank configured by using a box-shaped wall portion 859. The wall portion 859 forms an advection opening 852 (also referred to as an inflow port 852) and an advection opening 854. The inflow port 852 is, for example, a circular opening. The lower end of the inflow port 852 is arranged at the height of the reference water level LWL. The water flowing into the treatment water tank 840 from the advection opening 834 moves in the treatment water tank 840 in the + Z direction and reaches the inflow port 852. The solid matter contained in the water settles in the bottom of the treatment tank 840 and is separated. Water near the water surface WL of the treatment water tank 840 (water from which solid matter has been separated) flows into the disinfection tank 850 from the inflow port 852.

The overflow opening 854 is, for example, a rectangular opening. The overflow opening 854 is arranged at a position higher than the inflow port 852, and specifically, the lower end of the overflow opening 854 is arranged at the height of the high water level HWL. Further, the width of the overflow opening 854 in the horizontal direction is larger than the width of the inflow port 852. When the water level WL rises to the high water level HWL, the overflow opening 854 can transfer a large amount of water to the treatment tank 840 per unit time as compared with the inflow port 852. As a result, it is suppressed that the water level WL further rises from the high water level HWL.

The treatment water tank 840 is provided with a circulation air lift pump 920. As shown in FIG. 2, the suction port 921 of the circulation air lift pump 920 is arranged at the bottom of the treatment water tank 840 (in this embodiment, a position lower than the plurality of through holes of the air diffusers 838a and 838b). The outlet 922 of the circulation air lift pump 920 is arranged above the settling separation tank 810 (above the inflow baffle 812 in this embodiment). Gas from the blower 500 is supplied to the circulation air lift pump 920. The circulation air lift pump 920 can transfer the solid matter (for example, sludge) deposited on the bottom of the treatment water tank 840 to the settling separation tank 810 by using the gas from the blower 500.

The disinfection tank 850 (FIGS. 2 and 3 (A)) has a drug cylinder 856 filled with a disinfectant (for example, a solid chlorine agent). The water flowing into the disinfectant tank 850 from the inflow port 852 and the overflow opening 854 is disinfected in contact with the disinfectant. The disinfected water is discharged to the outside of the wastewater treatment device 800 through the discharge port 804.

When the wastewater flows into the wastewater treatment device 800 through the inflow port 802, the same amount of water as the inflowed water flows from the settling separation tank 810 to the anaerobic filter bed tank 820 through the advection opening 814. Further, the same amount of water is transferred from the anaerobic filter bed tank 820 to the contact filter bed tank 830 through the openings 200 and 300, transferred from the contact filter bed tank 830 to the treatment water tank 840 through the advection opening 834, and flows from the treatment water tank 840. It is transferred to the disinfection tank 850 through the inlet 852, and flows out of the wastewater treatment device 800 from the disinfection tank 850 through the discharge port 804. The water level WL is approximately the same in the treatment tanks 810, 820, 830, and 840 on the upstream side of the disinfection tank 850. Further, the size of the inflow port 852 of the disinfection tank 850 is configured to be small so as to prevent a large amount of water from flowing from the treatment water tank 840 to the disinfection tank 850 within a short time. For example, when a large amount of wastewater temporarily flows into the wastewater treatment device 800 (for example, at the time of peak inflow), the inflow port 852 is a unit time of water advected from the treatment water tank 840 through the inflow port 852 to the disinfection tank 850. The amount of hit is limited to less than the amount of water flowing into the wastewater treatment apparatus 800 per unit time. As a result, the water level WL of the treatment tanks 810, 820, 830, and 840 rises from the low water level LWL.

FIG. 3B is a schematic view of the gas flow path. An air supply port 807 is fixed to the tank body 801 of the wastewater treatment device 800. Outside the tank body 801 the blower 500 is connected to the air supply port 807 via a pipe. Inside the tank body 801 the air supply tube 100 is connected to the air supply port 807, and the air supply tube 100 is branched into three tubes 110 to 130.

The first pipe 110 is branched into two pipes 111 and 112 via a three-way valve 838v (also referred to as a distribution valve 838v). The two pipes 111 and 112 are connected to the two air diffusers 838a and 838b, respectively. The second pipe 120 is connected to the sludge transfer air lift pump 910 via an adjustment valve 910v (also referred to as a transfer valve 910v). The third pipe 130 is connected to the circulation air lift pump 920 via an adjustment valve 920v (also referred to as a circulation valve 920v).

The transfer valve 910v can adjust the transfer amount per unit time (also referred to as the sludge transfer water amount) by the sludge transfer air lift pump 910. In this embodiment, the appropriate range of the sludge transfer water amount is predetermined. The user (for example, the manager of the wastewater treatment device 800) can find that the actual amount of water transferred from the outlet 912 of the sludge transfer air lift pump 910 (FIG. 2) to the settling separation tank 810 is in an appropriate range. It is preferable to adjust the transfer valve 910v so that it is inside.

The circulation valve 920v can adjust the transfer amount (also referred to as the circulating water amount) per unit time by the circulation air lift pump 920. In this embodiment, the appropriate range of the circulating water amount is predetermined. For example, the appropriate range of the circulating water amount is such that the total circulating water amount for one day when the circulating water amount is continued for one day is within the range of 2 times or more and 4 times or less of the daily average sewage amount. The quantity. The user adjusts the circulation valve 920v so that the actual amount of water transferred from the outlet 922 of the circulation air lift pump 920 (FIG. 2) to the settling separation tank 810 per unit time is within an appropriate range. Is preferable.

The distribution valve 838v can alleviate the bias of the air diffuser between the two air diffusers 838a and 838b. When the wastewater treatment device 800 is installed at an angle, air can be diffused from one of the air diffusers 838a and 838b more strongly than the other. The user preferably adjusts the distribution valve 838v so that the air diffused by the air diffusers 838a and 838b is approximately uniform.

The gas from the blower 500 is distributed to the three tubes 110, 120, 130 according to the valves 910v, 920v, 838v. In this embodiment, the blower 500 continuously supplies gas to the wastewater treatment device 800. Therefore, from the blower 500, a device for controlling the operation of the blower 500 such as a timer and a solenoid valve can be omitted.

A2. Configuration of openings 200, 300:
FIG. 4 is a schematic view of the wastewater treatment apparatus 800 viewed from the VV cross section in FIG. 3A facing the contact filter bed tank 830 side (here, the + X side). In the figure, the first opening 200 and the second opening 300 formed in the partition wall 829 are shown. At the bottom of the figure, an enlarged view of the portion of the partition wall 829 including the first opening 200 and the second opening 300 is shown.

In the wastewater treatment apparatus 800 of this embodiment, the first opening 200 and the second opening 300 are circular openings, respectively. The center 200c of the first opening 200 is arranged at the same height as the reference water level LWL, the upper end 200u of the first opening 200 is arranged at a position higher than the reference water level LWL, and the lower end 200d of the first opening 200 is the reference. It is located below the water level LWL. The upper end 200u of the first opening 200 is the highest part of the edge of the first opening 200. The lower end 200d of the first opening 200 is the lowest portion of the edge of the first opening 200. The upper and lower ends of the other openings are similarly identified. The center 300c of the second opening 300 is arranged at a position lower than the reference water level LWL, the upper end 300u of the second opening 300 is arranged at a height below the reference water level LWL, and the lower end 300d of the second opening 300 is located. , It is arranged at a position lower than the reference water level LWL. In this embodiment, the lower end 300d of the second opening 300 is arranged at a position lower than the lower end 200d of the first opening 200.

In the figure, the inner diameter D20 is the inner diameter of the first opening 200, and the inner diameter D30 is the inner diameter of the second opening 300. In this embodiment, D20 = D30. The first distance D1 is the distance in the vertical downward direction (−Z direction) from the center 200c of the first opening 200 to the center 300c of the second opening 300. The second distance D2 is the distance in the vertical downward direction (−Z direction) from the reference water level LWL to the upper end 300u of the second opening 300.

As shown in the figure, in this embodiment, the second opening 300 is arranged at a position lower than the first opening 200. Specifically, the first opening 200 extends from a position lower than the reference water level LWL to a position higher than the reference water level LWL. That is, the first opening 200 overlaps with the reference water level LWL. The second opening 300 is arranged so that the entire second opening 300 has a height equal to or lower than the reference water level LWL. As described above, the reason why the height is different between the first opening 200 and the second opening 300 is to promote the transfer of solid matter (for example, sludge) from the contact filter bed tank 830 to the anaerobic filter bed tank 820. Is.

FIG. 5 is an explanatory diagram of the sludge transfer mechanism. In the figure, a simplified anaerobic filter bed tank 820 and a contact filter bed tank 830 are shown. In the figure, in order to make the figure easier to see, the entire second opening 300 is shown at a position lower than the lower end 200d of the first opening 200, and the filter medium 826 and the contact material 836 are not shown. .. The solid arrow in the figure indicates the flow of water, and the dotted arrow indicates the flow of solid SS.

In the contact filter bed tank 830, the upward flow UF is generated by the bubbles G2 discharged from the air diffusers 838a and 838b. The water flowing upward reaches the water surface WL (here, the low water level LWL). The water that reaches the water surface WL moves in the horizontal direction along the water surface WL (arrow HF). In the contact filter bed tank 830, a downward flow DF is generated in a portion where the air diffuser is weak (for example, a portion that does not overlap with the air diffuser 838a and 838b when viewed downward (−Z direction)). A portion of the water moving along the water surface WL reaches the first opening 200. Since the first opening 200 extends from a position lower than the reference water level LWL to a position higher than the reference water level LWL, the water reaching the first opening 200 moves to the anaerobic filter bed tank 820 through the first opening 200. obtain. Such movement of water from the contact filter bed tank 830 to the upstream anaerobic filter bed tank 820 is likely to occur when the wastewater does not flow into the wastewater treatment device 800. The solid material SS in the contact filter bed tank 830 moves to the anaerobic filter bed tank 820 (in this embodiment, the second portion 822 communicating with the first opening 200) through the first opening 200 by such a flow of water. Can be.

In this embodiment, the second opening 300 is arranged at a position below the reference water level LWL. Therefore, the water flowing along the water surface WL is less likely to pass through the second opening 300 than the first opening 200. That is, the water flowing along the water surface WL is easy to advection from the first opening 200 to the anaerobic filter bed tank 820, and is difficult to advection from the second opening 300 to the anaerobic filter bed tank 820. As a result, the water that has moved from the first opening 200 to the anaerobic filter bed tank 820 can return to the contact filter bed tank 830 through the second opening 300. By using the first opening 200 and the second opening 300 having different heights, it is possible to constantly cause the circulation of water flowing through the first opening 200 and the second opening 300 as described above.

Since the air is not diffused in the anaerobic filter bed tank 820, the flow of water in the anaerobic filter bed tank 820 is slower than that in the contact filter bed tank 830. In particular, since air is not diffused in the second portion 822 communicating with the openings 200 and 300, the flow of water on the anaerobic filter bed tank 820 side of the openings 200 and 300 is gentle. Therefore, the solid material SS that has moved from the first opening 200 to the anaerobic filter bed tank 820 settles while the water that has moved from the first opening 200 to the anaerobic filter bed tank 820 moves to the second opening 300, and the second opening. It can settle to the bottom of the anaerobic filter bed 820 without returning from 300 to the contact filter bed 830. In this way, the solid material SS can be transferred from the contact filter bed tank 830 to the anaerobic filter bed tank 820 through the first opening 200. As described above, the solid matter deposited on the bottom of the anaerobic filter bed tank 820 is transferred to the settling separation tank 810 by the sludge transfer air lift pump 910 (FIG. 2). The sludge transfer air lift pump 910 can transfer the sludge generated in the contact filter bed tank 830 to the settling separation tank 810 in addition to the sludge generated in the anaerobic filter bed tank 820.

Further, as shown in FIG. 3, the first opening 200 and the second opening 300 are separated from each other when viewed vertically downward. Therefore, when water moves from the first opening 200 to the second opening 300, the solid matter contained in the water may settle without reaching the second opening 300. Here, in order to promote the sedimentation of the solid matter, it is preferable that the distance between the first opening 200 and the second opening 300 in the horizontal direction is long.

A3. Evaluation test:
Next, the test using the test tank and the result will be described. FIG. 6 is a schematic view of the test tank 1000. The test tank 1000 realizes the second portion 822 of the anaerobic filter bed tank 820, the contact filter bed tank 830, and the first opening 200 and the second opening 300. The test tank 1000 was formed using a transparent resin. Although not shown, a contact material corresponding to the contact material 836 and an air diffuser corresponding to the air diffusers 838a and 838b are also provided in the contact filter bed tank 830 of the test tank 1000. Hereinafter, as the code of the element of the test tank, the same code as the code of the corresponding element of the wastewater treatment apparatus 800 of the above embodiment is used.

6 (A) is a schematic view of the test tank 1000 viewed in the −Z direction, and FIG. 6 (B) is a schematic view of the test tank 1000 viewed in the −Y direction. (C) is a schematic view of the test tank 1000 viewed in the + X direction, and FIG. 6 (D) shows the anaerobic filter bed tank 820 side (here, from the DD cross section in FIG. 7 (A)). -X side) is a schematic view of the partition wall 829 viewed facing. As shown in FIG. 6A, the horizontal cross-sectional shape of the contact filter bed tank 830 is rectangular. The shape of the contact filter bed tank 830 is a substantially quadrangular prism having this horizontal cross-sectional shape as the bottom surface. The corners of the bottom are rounded. Further, as shown in FIG. 6A, the horizontal cross-sectional shape of the second portion 822 of the anaerobic filter bed tank 820 is a trapezoid whose width in the Y direction gradually decreases toward the −X side. The shape of the second portion 822 is a substantially quadrangular prism having this horizontal cross-sectional shape as the bottom surface. The bottom of the second portion 822 and the bottom of the contact filter bed tank 830 are arranged at the same height. Although not shown, a valve for draining water is provided at the lower part of each of the contact filter bed tank 830 and the second portion 822.

In the figure, the width W1a is the length of the bottom of the trapezoid of the second portion 822 on the −X side (width in the Y direction), and the width W1b is the length of the bottom of the trapezoid of the second portion 822 on the + X side (width in the Y direction). Width in the Y direction). The width W2 is the width of the contact filter bed tank 830 in the Y direction. The length L1 is the length of the second portion 822 in the X direction, and the length L2 is the length of the contact filter bed tank 830 in the X direction. The water depth H is the height of the reference water level LWL from the bottom of the test tank 1000 (here, the same as the bottom of the second portion 822 and the contact filter bed tank 830). In the test tank 1000 used in this test, W1a = 458 mm, W1b = 300 mm, W2 = 1000 mm, L1 = 186 mm, L2 = 350 mm, and H = 1200 mm.

The configuration (FIG. 4) of the first opening 200 and the second opening 300 of the test tank 1000 used in this test is as follows. D20 = D30 = 77 mm. For the first distance D1, three values of 0 mm, 50 mm and 100 mm were tested. That is, for the second distance D2, three values of -38.5 mm, 11.5 mm and 61.5 mm were tested. Note that D1 = 0 mm indicates that the first opening 200 and the second opening 300 are arranged at the same height.

The test method is as follows. First, the contact filter bed 830 and the second portion 822 are filled with water, and with the openings 200 and 300 closed with a lid, a predetermined amount of crushed toilet paper is used as a solid substance in the contact filter bed. It was put into the tank 830. Then, air was diffused in the contact filter bed tank 830, and the inside of the contact filter bed tank 830 was stirred. As a result, the distribution of solid matter in the contact filter bed tank 830 became approximately uniform. In this state, water in the contact filter bed tank 830 was sampled, and the concentration of suspended solids (also referred to as SS (suspended solid)) was measured. The suspended solids concentration is also referred to as SS (hereinafter, also referred to as SS concentration). Next, the lids of the openings 200 and 300 were removed while the air was diffused in the contact filter bed tank 830. As a result, a part of the solid matter in the contact filter bed tank 830 was moved to the second portion 822 through the first opening 200. After removing the lid, the water in the contact filter bed tank 830 was sampled every 30 minutes and the SS concentration was measured. When 180 minutes had passed since the lid was removed, the air diffusion was stopped. Then, after stopping the air diffusion, water in the second portion 822 was sampled, the SS concentration in the second portion 822 was measured, and the total amount of solid matter in the second portion 822 was calculated.

FIG. 7 is a graph showing the test results. In the graph of FIG. 7A, the horizontal axis shows the elapsed time (unit: minutes) after the lid is removed, and the vertical axis shows the concentration ratio (unit:%). The concentration ratio is the ratio of the SS concentration in the elapsed time to the SS concentration before the lid is removed. As shown in the figure, with respect to the first distance D1 of 0 mm, 50 mm, and 100 mm, the concentration ratio in the contact filter bed tank 830 decreased with the passage of time.

By observing the contact filter bed tank 830 in a diffused state with the lid removed, it was possible to confirm how the crushed solid matter moved, that is, the flow of water in the contact filter bed tank 830. There was a difference in the direction of water flow between the surface layer portion near the water surface WL and the portion deeper than the surface layer portion. In the deep part, an ascending flow was observed in response to the rising of the bubbles discharged by the air diffuser, and in the part with few bubbles, a descending flow was observed. As described above, in the portion distant from the water surface WL downward, a bidirectional flow parallel to the vertical direction was observed. In the vicinity of the water surface WL, many flows along the water surface WL, that is, flows in the horizontal direction were observed. It is presumed that the reason for this is that when the rising water reaches the water surface WL, the water cannot move to a position higher than the water surface WL, so that the water has to move in the horizontal direction.

A portion of the water moving along the water surface WL moved downward along the descending flow of the deep portion described above. In the vicinity of the first opening 200, water moving along the water surface WL passed through the first opening 200 and moved to the second portion 822. As a result, the solid matter in the contact filter bed tank 830 was moved to the second portion 822 through the first opening 200. The portion of the solid matter that had moved to the second portion 822 did not return to the contact filter bed tank 830, but settled to the bottom of the second portion 822. This observation result is consistent with the decrease in the proportion of SS concentration in the contact filter bed tank 830 with the passage of time in the graph of FIG. 7 (A).

When the first distance D1 is greater than zero, that is, when the heights differ between the first opening 200 and the second opening 300, in the first opening 200, the water is constantly in contact filter bed tank 830. At the second opening 300, water constantly flowed from the second portion 822 to the contact filter bed tank 830. The reason for this is that, as described with reference to FIG. 5, the water flowing along the water surface WL is easy to advection from the first opening 200 to the second portion 822, and is difficult to advection from the second opening 300 to the second portion 822. It is estimated to be.

On the other hand, when the first distance D1 is zero, that is, when the height is the same between the first opening 200 and the second opening 300, the contact is made between the first opening 200 and the second opening 300. The flow of water from the filter bed 830 to the second portion 822 and the flow of water from the second portion 822 to the contact filter bed 830 occurred irregularly. It is presumed that the reason for this is that the water flowing along the water surface WL is likely to be advected to the second portion 822 in both the first opening 200 and the second opening 300.

These observations show that in the graph of FIG. 7A, the concentration ratio is significantly smaller when the first distance D1 is larger than zero as compared with the case where the first distance D1 is zero. It is consistent. Specifically, in the case of D1 = 0 mm (D2 = -38.5 mm), the concentration ratio at the elapsed time of 180 minutes exceeded 20%, but D1 ≧ 50 mm (D2 ≧ 11.5 mm). In the case of, the concentration ratio at the elapsed time of 180 minutes improved to 15% or less.

The graph of FIG. 7B shows the return rate (unit:%) of the first distance D1 of 0 mm, 50 mm, and 100 mm, respectively. Here, the return rate is the ratio of the total amount of solids in the second portion 822 after the 180-minute test to the total amount of solids charged into the contact filter bed tank 830. As shown in the figure, the return rate was significantly improved when the first distance D1 was larger than zero as compared with the case where the first distance D1 was zero. Specifically, when D1 = 0 mm (D2 = -38.5 mm), the return rate was less than 70%, but when D1 ≧ 50 mm (D2 ≧ 11.5 mm), the return rate was , Over 75%. This measurement result is consistent with the fact that in the graph of FIG. 7A, the concentration ratio is significantly smaller when the first distance D1 is larger than zero as compared with the case where the first distance D1 is zero. is doing. The reason why the total of the concentration ratio in the elapsed time of 180 minutes in FIG. 7 (A) and the return rate in FIG. 7 (B) is smaller than 100% is that a part of the solid matter is in the contact filter bed tank. This is because it adhered to the contact material of 830.

As described above, the lower end 200d of the first opening 200 (FIG. 4) is arranged at a position lower than the reference water level LWL, and the upper end 200u of the first opening 200 is arranged at a position higher than the reference water level LWL. In the case, the solid matter of the contact filter bed tank 830 can be easily transferred to the second portion 822 (that is, the anaerobic filter bed tank 820) through the first opening 200. Then, at least a part of the solid matter that has moved to the anaerobic filter bed tank 820 is settled at the bottom of the anaerobic filter bed tank 820 without returning to the contact filter bed tank 830. Therefore, the solid matter can be transferred from the contact filter bed tank 830 to the anaerobic filter bed tank 820 without using a transfer device such as an air lift pump. In particular, in this embodiment, the anaerobic filter bed tank 820 is not provided with an air diffuser, and the contact filter bed tank 830 is provided with an air diffuser. Therefore, the water flow moving from the contact filter bed tank 830 to the anaerobic filter bed tank 820 through the first opening 200 can be easily realized. Further, when the upper end 300u of the second opening 300 is arranged at a position lower than the reference water level LWL, the ease of water flow from the first opening 200 to the anaerobic filter bed tank 820 and the ease of water flow from the second opening 300 An appropriate difference can be provided between the ease of water flow to the anaerobic filter bed tank 820 and the ease of water flow. As a result, the flow of water constantly flowing from the contact filter bed tank 830 to the anaerobic filter bed tank 820 through the first opening 200 and flowing from the anaerobic filter bed tank 820 to the contact filter bed tank 830 through the second opening 300. Can be caused. This can facilitate the transfer of solids from the contact filter bed tank 830 to the anaerobic filter bed tank 820 through the first opening 200, as compared to the case where the two openings 200, 300 are arranged at the same height. Then, it is possible to suppress an increase in the amount of solid matter in the contact filter bed tank 830. As a result, the blockage of the contact filter bed tank 830 can be suppressed. In addition, the frequency of backwashing of the contact filter bed tank 830, which is necessary for proper operation of the wastewater treatment device 800, can be reduced. In addition, it is possible to suppress an increase in the load on the contact filter bed tank 830. As a result, the contact filter bed tank 830 can be miniaturized. In the backwashing of the contact filter bed tank 830, for example, the distribution valve 838v is used so that one of the first air diffuser 838a and the second air diffuser 838b disperses air and the other stops air dispersal. It can be achieved by adjusting. The user preferably performs such backwashing at the time of inspection of the wastewater treatment apparatus 800.

Further, when the shape of the first opening 200 and the shape of the second opening 300 are circular shapes having the same inner diameter as in the test tank 1000 of FIG. 6, the first opening 200 and the second opening 300 are used. It can be easily formed. For example, the openings 200 and 300 can be easily formed by using a hole saw having the same outer diameter. Further, the center 300c of the second opening 300 is arranged at a position lower than the center 200c of the first opening 200. Therefore, the first opening 200 and the second opening 300 that can promote the movement of the solid matter through the first opening 200 can be easily formed.

Further, as described with reference to FIGS. 2 and 3, the anaerobic filter bed tank 820 of the present embodiment includes an advection baffle 823. In this embodiment, the entire lower opening 824 on the lower side of the advection baffle 823 is arranged at a position lower than both the lower end 200d of the first opening 200 and the lower end 300d of the second opening 300. The advection baffle 823 communicates the lower opening 824 with the openings 200 and 300. Therefore, when water is transferred from the anaerobic filter bed tank 820 to the contact filter bed tank 830 through the openings 200 and 300, the water has a height of the lower opening 824 or less of the advection baffle 823 of the anaerobic filter bed tank 820. After moving the portion, it rises to openings 200, 300. At this time, the solid matter contained in the water may settle to the bottom of the anaerobic filter bed tank 820 without rising to the openings 200 and 300. As a result, the anaerobic filter bed tank 820 can store the solid matter in the bottom portion (particularly, the portion lower than the lower end 824 d of the lower opening 824). Further, the anaerobic filter bed tank 820 can also store solid matter transferred from the contact filter bed tank 830 to the anaerobic filter bed tank 820 through the first opening 200 at the bottom. In this embodiment, the lower opening 824 is an opening that is vertical (that is, horizontal) in the vertical direction. Therefore, the entire lower opening 824 (more specifically, the entire edge of the lower opening 824) corresponds to the lower end 824d of the lower opening 824.

Further, as described with reference to FIGS. 2 and 3, the wastewater treatment apparatus 800 of this embodiment includes a sludge transfer air lift pump 910. The suction port 911 of the sludge transfer air lift pump 910 is arranged at the bottom of the anaerobic filter bed tank 820, and the outlet 912 of the sludge transfer air lift pump 910 is arranged in the settling separation tank 810. Therefore, the sludge transfer air lift pump 910 contacts the water in the anaerobic filter bed tank 820 (and by extension, solid matter such as sludge) with the anaerobic filter bed tank 820 of the plurality of treatment tanks 810 to 850 of the wastewater treatment device 800. It can be transferred to another settling separation tank 810 which is different from the filter bed tank 830. As a result, even when the solid matter moves from the contact filter bed tank 830 to the anaerobic filter bed tank 820 through the opening 200, it is possible to suppress an increase in the amount of the solid matter in the anaerobic filter bed tank 820.

In particular, in this embodiment, the entire suction port 911 of the sludge transfer air lift pump 910 is located at a position lower than both the lower end 200d of the first opening 200 and the lower end 300d of the second opening 300 in the anaerobic filter bed tank 820. Have been placed. Therefore, the sludge transfer air lift pump 910 can appropriately transfer the solid matter deposited on the bottom of the anaerobic filter bed tank 820. Further, in this embodiment, the entire suction port 911 is arranged at a position lower than the lower end 824d of the lower opening 824 of the advection baffle 823. Therefore, the sludge transfer air lift pump 910 can appropriately transfer the solid matter deposited at a position lower than the lower end 824 d of the lower opening 824 to the outside of the anaerobic filter bed tank 820.

Further, the water flowing into the anaerobic filter bed tank 820 (FIG. 2) is introduced into the anaerobic filter bed tank 820 by the advection opening 814 (hereinafter, the advection opening 814 is also referred to as an advection portion 814). In this embodiment, the lower end 814d of the advection opening 814 is located higher than the upper end 824u of the lower opening 824 of the advection baffle 823. Therefore, the water introduced from the advection opening 814 into the anaerobic filter bed tank 820 flows downward from the advection opening 814 to the lower opening 824 of the advection baffle 823. As a result, the sedimentation of solid matter contained in water can be promoted. As described above, since the lower opening 824 of the advection baffle 823 is a horizontal opening, the entire lower opening 824 (more specifically, the entire edge of the lower opening 824) is the upper end 824u of the lower opening 824. Corresponds to.

Further, the wastewater treatment device 800 is provided with an advection opening 834 that communicates the contact filter bed tank 830 and the treatment water tank 840 (hereinafter, also referred to as a communication portion 834). In this embodiment, the entire advection opening 834 is arranged at a position lower than both the lower end 200d of the first opening 200 and the lower end 300d of the second opening 300. Therefore, the solid matter that has moved to a position lower than the openings 200 and 300 without moving to the anaerobic filter bed tank 820 in the contact filter bed tank 830 can be moved to the treatment water tank 840 through the advection opening 834. Further, the wastewater treatment device 800 includes a circulation air lift pump 920. The circulation air lift pump 920 transfers the water in the treatment water tank 840 to the settling separation tank 810, which is a different treatment tank from the treatment tanks 820, 830, and 840. As a result, the solid matter that has moved from the contact filter bed tank 830 to the treatment water tank 840 can be transferred to another treatment tank (in this embodiment, the settling separation tank 810) by the circulation air lift pump 920. In this way, the solid matter in the contact filter bed tank 830 is transferred to another treatment tank through the treatment water tank 840 and the circulation air lift pump 920, so that the amount of solid matter in the contact filter bed tank 830 increases. Can be suppressed.

In particular, in this embodiment, the sludge transfer air lift pump 910 is provided on the upstream side of the contact filter bed tank 830, and the circulation air lift pump 920 is provided on the downstream side of the contact filter bed tank 830. Then, the solid matter in the contact filter bed tank 830 can be moved to the anaerobic filter bed tank 820 and transferred by the sludge transfer air lift pump 910. Further, the solid matter in the contact filter bed tank 830 may move to the treatment water tank 840 and be transferred by the circulation air lift pump 920. As described above, the solid matter in the contact filter bed tank 830 can be transferred by both the sludge transfer air lift pump 910 on the upstream side and the circulation air lift pump 920 on the downstream side. Therefore, it is possible to prevent the amount of solid matter in the contact filter bed tank 830 from becoming excessive.

Further, in the contact filter bed tank 830 (FIG. 2), the regions where the water directed to the sludge transfer air lift pump 910 on the upstream side flows out from the contact filter bed tank 830 are the regions of openings 200 and 300. Further, in the contact filter bed tank 830, the region where the water directed to the circulation air lift pump 920 on the downstream side flows out from the contact filter bed tank 830 is the region of the advection opening 834. In this embodiment, the entire advection opening 834 is arranged at a position lower than any of the lower ends 200d and 300d of the openings 200 and 300. Therefore, the solid matter existing in the relatively high portion of the contact filter bed tank 830 is removed from the opening 200 at a relatively high position. Solids present in the relatively low portion of the contact filter bed 830 are removed from the relatively low advection opening 834. In this way, solid matter is removed from both the relatively high region (here, openings 200, 300) and the relatively low region (here, advection opening 834) of the contact filter bed tank 830. It is possible to suppress a large deviation in the solid matter concentration in the contact filter bed tank 830.

A4. Fluctuations in water level WL and transfer of solids:
Next, it is explanatory drawing of the mechanism of the transfer of the solid matter using the fluctuation of the water level WL. 8 (A) and 8 (B) show the wastewater treatment apparatus 800, which is simplified in the same manner as in FIG. 5, respectively. FIG. 8A shows a state in which the water level WL is a low water level LWL, and FIG. 8B shows a state in which the water level WL is a high water level HWL.

In the state of FIG. 8A, as also described in FIG. 5, the solid material SS in the contact filter bed tank 830 can move to the second portion 822 of the anaerobic filter bed tank 820 through the first opening 200. Then, the sludge transfer air lift pump 910 can transfer the solid material SS from the bottom of the anaerobic filter bed tank 820 to the settling separation tank 810. The lift H1a in the figure indicates the height at which water is actually pumped by the sludge transfer air lift pump 910 (loss of piping, etc. is omitted). Further, the solid material SS in the contact filter bed tank 830 can move to the treated water tank 840 through the communication portion 834. Then, the circulation air lift pump 920 can transfer the solid material SS from the bottom of the treated water tank 840 to the settling separation tank 810. The lift H2a in the figure indicates the height at which water is actually pumped by the circulating air lift pump 920 (loss of piping, etc. is omitted).

As shown in FIG. 8B, the sludge transfer air lift pump 910 is an anaerobic filter bed as in the case where the water level WL is the high water level HWL and the water level WL is the low water level LWL (FIG. 8A). The solid SS can be transferred from the tank 820 to the settling separation tank 810, and the circulation air lift pump 920 can transfer the solid SS from the treated water tank 840 to the settling separation tank 810.

Here, the water level WL is rising from the low water level LWL to the high water level HWL. Therefore, the lift H1b of the sludge transfer air lift pump 910 is smaller than the lift H1a in the state of WL = LWL (FIG. 8 (A)). As described above, since the lift H1b becomes smaller, the amount of water transferred by the sludge transfer air lift pump 910 per unit time becomes larger than that in the state of WL = LWL (FIG. 8A). As a result, the transfer of the solid SS from the anaerobic filter bed tank 820 to the settling separation tank 810 is promoted.

Similarly, the lift H21b of the circulation air lift pump 920 is smaller than the lift H2a in the state of WL = LWL (FIG. 8 (A)). As described above, since the lift H2b becomes smaller, the amount of water transferred by the circulating air lift pump 920 per unit time becomes larger than that in the state of WL = LWL (FIG. 8A). As a result, the transfer of the solid SS from the treated water tank 840 to the settling separation tank 810 is promoted.

FIG. 9 is a graph showing an example of fluctuation of the water level WL at the time of peak inflow. The horizontal axis shows the elapsed time T (unit: minutes) from the start of the peak inflow, and the vertical axis shows the height HL (unit: cm) of the water level WL measured from the low water level LWL. HL = zero indicates that the height of the water level WL is the same as that of the low water level LWL. The first graph G1 shows the test result using the test tank of the wastewater treatment apparatus 800, and the second graph G2 shows the result of the simulation. The test tank is the above-mentioned wastewater treatment device 800 realized by assuming that the number of people to be treated = 7 people. The advection opening 852 of the disinfection tank 850 is a circular opening having an inner diameter of 25 mm. The inner diameter of the advection opening 852 is significantly smaller than the size of the advection opening commonly used when it is not intended to raise the water level in the treatment tank during peak inflow (eg, the inner diameter is 77 mm). .. Further, the peak inflow is such that the inflow of water to the wastewater treatment device 800 at an inflow rate of 47 L / min continues so that the total amount of inflow water is 308 L. This peak inflow is the same as the peak inflow used in the performance evaluation test of the septic tank of the 7-person tank.

The inflow time Ti in FIG. 9 is the duration of the peak inflow. In this test, it is 6.6 minutes. As shown, during this inflow time Ti, the height HL of the water level WL rises from the low water level LWL. Then, after the inflow time Ti elapses, that is, after the peak inflow ends, the height HL of the water level WL gradually decreases.

The decrease time Tx in the figure is the time from the end of the peak inflow until the height HL of the water level WL returns to the low water level LWL. The rate of change of the height HL of the water level WL becomes slower as the water level WL is closer to the low water level LWL. Therefore, in this test, the water level WL reaches the low water level LWL when the advection speed from the treatment water tank 840 to the disinfection tank 850 (that is, the discharge speed from the wastewater treatment device 800) becomes 0.5 L / min or less. As a result, it was decided to specify the decrease time Tx. The decrease time Tx of the first graph G1 showing the test result was 21 minutes.

As shown in the figure, the second graph G2 showing the simulation result is substantially in agreement with the first graph G1 showing the test result. In this way, the simulation appropriately reproduces the fluctuation of the water level WL in the actual test tank.

As described in FIG. 8B, the air lift pump is used during a period in which the water level WL is higher than the low water level LWL due to the peak inflow (for example, the period Tu from the start of the inflow time Ti to the end of the decrease time Tx in FIG. 9). The transfer of solid SS by 910, 920 is facilitated. When the wastewater treatment device 800 treats wastewater from ordinary households, such peak inflow occurs naturally several times a day (for example, twice). The sludge transfer air lift pump 910 utilizes such a variation in the amount of naturally occurring inflow water per unit time to settle and separate the solid SS from the anaerobic filter bed tank 820 without using additional energy. Can be transferred to. As a result, the sludge transfer air lift pump 910 appropriately suppresses an increase in energy consumed for operating the wastewater treatment system 900, while increasing the amount of solid SS in the anaerobic filter bed tank 820. , Can be suppressed. Similarly, the circulation air lift pump 920 can appropriately suppress an increase in the amount of solid SS in the treated water tank 840 while suppressing an increase in energy consumption.

In this embodiment, the blower 500 (FIGS. 1 and 3 (B)) constantly supplies air to the wastewater treatment apparatus 800 regardless of the water level WL. That is, the sludge transfer air lift pump 910 constantly transfers water from the anaerobic filter bed tank 820 to the settling separation tank 810 regardless of the water level WL. Then, when the water level WL rises from the low water level LWL, the transfer amount per unit time by the sludge transfer air lift pump 910 increases. Similarly, the circulation air lift pump 920 constantly transfers water from the treatment water tank 840 to the settling separation tank 810 regardless of the water level WL. Then, when the water level WL rises from the low water level LWL, the transfer amount per unit time by the circulation air lift pump 920 increases.

For example, in the above-mentioned test tank (treatment target personnel = 7 people) of the wastewater treatment apparatus 800, when the water level WL is a low water level LWL, the transfer amount per unit time by the circulation air lift pump 920 is approximately 3.5 L /. It was min. When the water level WL was higher than the low water level LWL, the amount transferred by the circulating air lift pump 920 increased approximately in proportion to the height HL of the water level WL from the low water level LWL. When the height HL of the water level WL was 8 cm, the transfer amount was approximately 9.9 L / min. In this way, when the water level WL rises from the low water level LWL, the transfer amount per unit time by the circulation air lift pump 920 increases appropriately. Similarly, the amount transferred by the sludge transfer air lift pump 910 increases when the water level WL rises from the low water level LWL.

The longer the reduction time Tx, the longer the time for promoting the transfer of the solid material SS by the air lift pumps 910 and 920. Therefore, in order to suppress an increase in the amount of solid SS in the treatment tanks 820 and 840, it is preferable that the reduction time Tx is long. Here, by reducing the size of the advection opening 852 (for example, inner diameter, area, etc.), the reduction time Tx can be lengthened.

FIG. 10 is a table showing the results of a simulation of fluctuations in the water level WL. This table shows the number of personnel N to be treated, the area S (m ² ) of the water surface at WL = LWL, the daily average sewage amount Q (L / day), the peak inflow flow velocity Fp (L / min), and the day. Ratio Rp (%) of peak inflow rate Qp to average sewage volume Q, peak inflow rate Qp (L), inner diameter D (mm) of advection opening 852, and horizontal width W (mm) of advection opening 854. The maximum amount of increase in water level WL from the low water level LWL at the time of peak inflow Hmax (mm), inflow time Ti (minutes), decrease time Tx (minutes), and from the treatment water tank 840 to the disinfection tank 850 at the time of peak inflow. The correspondence relationship with the ratio Ro (%) of the amount of water transferred through the overflow opening 854 to the total amount of advected water is shown (in parentheses, the unit). The area S is the sum of the areas of the water surface WL of the treatment tanks 810 to 840. The flow velocity Fp, the ratio Rp, the peak inflow amount Qp, and the inflow time Ti are the same as the peak inflow parameters Fp, Rp, Qp, and Ti corresponding to the processing target personnel N used in the performance evaluation test. As described above, the same inflow as the peak inflow used in the performance evaluation test of the septic tank was used as the peak inflow. Further, the peak inflow may be determined by the flow velocity Fp and the peak inflow amount Qp (the ratio Rp is calculated by Q / Qp, and the inflow time Ti is calculated by Qp / Fp).

The values of the 7 personnel to be processed N indicate the configuration of the test tank used for specifying the first graph G1 in FIG. 9 and the test results. The values of the number of people N to be processed other than 7 indicate the configuration and result of the simulation. This simulation is the same as the simulation used for identifying the second graph G2 in FIG. Therefore, it is presumed that the simulation result when the number of personnel N to be treated is different from 7 is accurately reproduced as the result when the actual wastewater treatment device 800 is used.

As shown in the figure, the inner diameter D of the advection opening 852 was 25 mm when N = 7 and 35 mm when 14 ≦ N. When N = 35, 42, 50, two advection openings 852 having an inner diameter D of 35 mm were provided. When N ≦ 30, the total number of advection openings 852 was one. As described above, the inner diameter D of the advection opening 852 was large when the number of personnel N to be processed was large. In addition, the total number of advection openings 852 was large when the number of personnel N to be processed was large. As described above, the total area of the advection opening 852 was large when the number of personnel N to be treated was large.

As shown in the figure, the reduction time Tx was 16 minutes or more and 53 minutes or less in any of the processing target personnel N. As described above, the configuration of the advection opening 852 (here, the inner diameter D and the total number) of each processing target personnel N was able to realize a long reduction time Tx of 16 minutes or more. When the reduction time Tx is long, the transfer of the solid material SS by the air lift pumps 910 and 920 is promoted. That is, the configuration of the advection opening 852 of each processing target personnel N can promote the transfer of the solid material SS.

By the way, even in a septic tank that is not intended to raise the water level of the treatment tank at the time of peak inflow, the water level may rise at the time of peak inflow. However, the decrease time Tx is short, for example, about 10 minutes when N = 7.

In order to promote the transfer of the solid material SS by the air lift pumps 910 and 920, it is preferable that the size (for example, area) of the advection opening 852 is configured so that the reduction time Tx becomes longer. For example, the reduction time Tx is preferably more than 10 minutes, particularly preferably 13 minutes or more, and most preferably 16 minutes or more.

On the other hand, when the decrease time Tx is excessively long, a large amount of water is transferred from the treatment tanks 820 and 840 to the settling separation tank 810 by the air lift pumps 910 and 920. The transfer of such a large amount of water can adversely affect the treatment of the treatment tanks 810 to 840. For example, when a large amount of water containing oxygen is transferred to the settling separation tank 810 by the sludge transfer air lift pump 910, the anaerobic microorganisms of the settling separation tank 810 and the anaerobic filter bed tank 820 on the downstream side of the settling separation tank 810. Activity can be suppressed. Therefore, it is preferable that the size (for example, area) of the advection opening 852 is configured so that the reduction time Tx does not become excessively long. For example, the reduction time Tx is preferably 90 minutes or less, particularly preferably 75 minutes or less, and most preferably 60 minutes or less.

The preferred range of the decrease time Tx may be specified based on the inflow time Ti. For example, in the example of FIG. 10, the ratio (Tx / Ti) of the decrease time Tx to the inflow time Ti is in the range of 2.07 or more and 3.27 or less. It is presumed that such a range indicates a reasonable range between the inflow time Ti and the decrease time Tx. Here, the decrease time Tx is preferably at least the inflow time Ti, particularly preferably at least 1.5 times the inflow time Ti, and most preferably at least twice the inflow time Ti. The decrease time Tx is preferably 5 times or less of the inflow time Ti, particularly preferably 4 times or less of the inflow time Ti, and most preferably 3.5 times or less of the inflow time Ti.

The configuration of the advection opening 852 may be various configurations that realize the reduction time Tx within the above preferable range.

In either case, the peak fluctuation time (specifically, the time from the start of the peak inflow to the wastewater treatment device until the water level WL returns to the low water level LWL after the water level WL rises from the low water level LWL). , Time of period Tu in FIG. 9) is preferably 1 hour or less. According to this configuration, the transfer of excess water from the treatment tanks 820 and 840 to the settling separation tank 810 by the air lift pumps 910 and 920 is suppressed, so that the deterioration of the treatment performance of the treatment tanks 810 to 840 can be suppressed. As a method for adjusting the peak fluctuation time, a method of adjusting the respective configurations of the advection opening 852 and the overflow opening 854 of the disinfection tank 850 may be adopted. For example, the larger the advection opening 852, the shorter the peak fluctuation time. Further, the wider the overflow opening 854, the shorter the peak fluctuation time.

In addition, the maximum amount of increase Hmax was 60 mm or more and 73 m or less in any of the treated personnel N. As described above, the configuration of the advection opening 852 (here, the inner diameter D and the total number) of each processing target personnel N was able to realize a large maximum increase amount Hmax of 60 mm or more. When the maximum increase amount Hmax is large, the lift of the air lift pumps 910 and 920 becomes small, so that the transfer of the solid material SS by the air lift pumps 910 and 920 is promoted. That is, the configuration of the advection opening 852 of each processing target personnel N can promote the transfer of the solid material SS.

By the way, even in a septic tank that is not intended to raise the water level of the treatment tank at the time of peak inflow, the water level may rise at the time of peak inflow. However, the maximum amount of increase Hmax is small, for example, when N = 7, it is about 39 mm.

In order to promote the transfer of the solid material SS by the air lift pumps 910 and 920, it is preferable that the size (for example, area) of the advection opening 852 is configured so that the maximum increase amount Hmax becomes larger. For example, the maximum amount of increase Hmax is preferably 40 mm or more, particularly preferably 50 mm or more, and most preferably 60 mm or more.

On the other hand, when the maximum increase amount Hmax is excessively large, water may unintentionally overflow from any of the treatment tanks 81 to 850. Therefore, it is preferable that the size (for example, area) of the advection opening 852 is configured so that the maximum amount of increase Hmax is not excessively large. For example, the water level WL corresponding to the maximum rising amount Hmax is preferably a high water level HWL + 50 mm or less, particularly preferably a high water level HWL + 40 mm or less, and most preferably a high water level HWL + 30 mm or less.

The configuration of the advection opening 852 may be various configurations that realize the maximum amount of increase Hmax within the above preferable range.

The configuration of the advection opening 852 (for example, inner diameter D, total number, total area, shape, etc.) may be various. For example, the shape of the advection opening 852 may be rectangular. Generally, the size of the advection opening 852 is such that the amount of inflow water into the wastewater treatment apparatus 800 per unit time is temporarily increased by the peak inflow preliminarily associated with the wastewater treatment apparatus 800. By limiting the amount of water advected through the advection opening 852 per unit time to less than the amount of peak inflow per unit time, the water level between the anaerobic filter bed tank 820 and the contact filter bed tank 830 is temporarily raised. It is preferable that it is configured so as to allow. According to this configuration, the water level WL of the anaerobic filter bed tank 820 temporarily rises at the time of peak inflow, so that the solid SS is transferred from the anaerobic filter bed tank 820 to the settling separation tank 810 by the sludge transfer air lift pump 910. , Can be promoted.

Further, as the peak inflow associated with the wastewater treatment device 800 in advance, the peak inflow used in the performance evaluation test of the wastewater treatment device 800 can be adopted. Further, when the wastewater treatment apparatus 800 is not the subject of the performance evaluation test, the peak inflow configuration is designed to be accepted by the wastewater treatment apparatus 800 when the wastewater treatment apparatus 800 is continuously used. It may be the same as the configuration of the peak inflow. As such a design peak inflow configuration, the configuration described in documents related to the wastewater treatment apparatus 800 (for example, an instruction manual, specifications, etc.) may be adopted.

B. Modification example:
(1) The configurations of the openings 200 and 300 may be various other configurations instead of the configurations described above. For example, the inner diameter D30 of the second opening 300 may be different from the inner diameter D20 of the first opening 200. Further, at least one of the shapes of the first opening 200 and the second opening 300 may have a shape different from the circular shape (for example, a rectangular shape or an elliptical shape). Further, in the embodiment of FIG. 4 and the embodiments of FIGS. 11 and 12, which will be described later, the position of the center 200c of the first opening 200 may be higher than the reference water level LWL, and may be higher than the reference water level LWL. May also be in a low position.

Further, as described above, according to the observation result of the test tank 1000, water easily flows along the water surface WL in the vicinity of the water surface WL. In order for the water flowing along the water surface WL to pass through the first opening 200, the lower end 200d of the first opening 200 is arranged at a position lower than the reference water level LWL, and the upper end 200u of the first opening 200 is the reference water level. It is preferable that it is arranged at a position higher than LWL. According to this configuration, the water flowing along the water surface WL can easily pass through the first opening 200, so that the solid matter can be transferred through the first opening 200 by this water flow.

Further, it is preferable that the upper end 300u of the second opening 300 is located at a height equal to or lower than the reference water level LWL and lower than the upper end 200u of the first opening 200. According to this configuration, water is relatively easy to flow from the contact filter bed tank 830 to the anaerobic filter bed tank 820 through the first opening 200, and from the contact filter bed tank 830 to the anaerobic filter bed tank 820 through the second opening 300. Is relatively difficult to flow. Therefore, water can constantly flow from the contact filter bed tank 830 to the anaerobic filter bed tank 820 through the first opening 200, and from the anaerobic filter bed tank 820 to the contact filter bed tank 830 through the second opening 300. As a result, the transfer of solid matter from the contact filter bed tank 830 to the anaerobic filter bed tank 820 can be promoted through the first opening 200. For example, the upper end 200u of the first opening 200 may be higher than the reference water level LWL, and the upper end 300u of the second opening 300 may be arranged at the same height as the reference water level LWL. Further, in order to prevent the water flowing along the water surface WL from flowing into the second opening 300, it is preferable that the upper end 300u of the second opening 300 is arranged at a position lower than the reference water level LWL. For example, the upper end 200u of the first opening 200 may be arranged at the same height as the reference water level LWL, and the upper end 300u of the second opening 300 may be arranged at a position lower than the reference water level LWL.

As described in the test results of FIG. 7, good concentration ratios and return rates were realized in all cases of D1 = 50 mm and 100 mm (that is, D2 = 11.5 mm and 61.5 mm). Therefore, as a preferable range of the second distance D2 from the reference water level LWL (FIG. 4) to the upper end 300u of the second opening 300, a range of 11.5 mm or more and 61.5 mm or less can be adopted. In addition, since the second distance D2 (11.5 mm) close to zero achieved a good concentration ratio and return rate, various second distance D2s of zero or more and less than 11.5 mm achieved a good concentration ratio and return rate. It is estimated that the rate can be achieved. In addition, the second distance D2 (61.5 mm), which is sufficiently larger than zero, realized a good concentration ratio and a return rate. It is presumed that the fact that the second distance D2 is further large does not become a factor that suppresses the transfer of solid matter through the openings 200 and 300. Therefore, it is presumed that various second distances D2 of 61.5 mm or more can also achieve a good concentration ratio and return rate.

It is preferable that the lower end 200d of the first opening 200 is arranged at a position higher than the lower end 300d of the second opening 300. According to this configuration, the solid matter moved to the anaerobic filter bed tank 820 through the first opening 200 is settled at a position lower than the lower end 200d of the first opening 200, and then the contact filter bed tank 830 is passed through the first opening 200. It is possible to suppress the return to.

Further, both the upper end 200u of the first opening 200 and the upper end 300u of the second opening 300 may be arranged at a height equal to or higher than the reference water level LWL. That is, the first opening 200 and the second opening 300 may each extend from a position lower than the reference water level LWL to a position higher than the reference water level LWL. FIG. 11 is a schematic view showing a modified example of the openings 200 and 300. The only difference from the embodiment shown in FIG. 4 is that the second opening 300 is arranged at a position where it overlaps with the reference water level LWL. In the modified example of FIG. 11, the upper end 300u of the second opening 300 is higher than the reference water level LWL, and the lower end 300d of the second opening 300 is lower than the reference water level LWL. Further, the center 300c of the second opening 300 is lower than the center 200c of the first opening 200. Further, the center 300c of the second opening 300 is lower than the reference water level LWL. Further, the lower end 300d of the second opening 300 is lower than the lower end 200d of the first opening 200.

The first width W20 in the figure is the width of the first opening 200 at the height of the reference water level LWL. The second width W30 is the width of the second opening 300 at the height of the reference water level LWL. In the modified example of FIG. 11, the first width W20 is wider than the second width W30. According to this configuration, the water flowing along the water surface WL (here, the reference water level LWL) is easily advected from the contact filter bed tank 830 to the anaerobic filter bed tank 820 through the first opening 200, and from the contact filter bed tank 830. It is difficult to advection to the anaerobic filter bed tank 820 through the second opening 300. Therefore, it is presumed that the solid matter can be appropriately transferred through the first opening 200.

The first width W20 of the first opening 200 is represented by the shortest distance between two portions P2a and P2b of the height of the reference water level LWL in the loop-shaped edge of the first opening 200. Similarly, the second width W30 of the second opening 300 is represented by the shortest distance between the two portions P3a, P3b of the height of the reference water level LWL in the looped edge of the second opening 300.

Further, the total number of the first openings may be 2 or more. Further, the total number of the second openings may be 2 or more. FIG. 12 is a schematic view showing a modified example of the opening formed in the partition wall. The difference from the embodiment shown in FIG. 4 is that two first openings 200 and two second openings 300 are provided. The height of each of the two first openings 200 in FIG. 12 is the same as the height of the first opening 200 in FIG. The height of each of the two second openings 300 in FIG. 12 is the same as the height of the second opening 300 in FIG. In the modified example of FIG. 12, the first opening 200 and the second opening 300 are alternately arranged along the horizontal direction (here, the Y direction). When the number of personnel to be treated is large (for example, when the number of personnel to be treated is 14 or more), the amount of water advected from the anaerobic filter bed tank 820 to the downstream contact filter bed tank 830 may be large. In such a case, if at least one of the total number of the first openings and the total number of the second openings is 2 or more, smooth advection of water from the anaerobic filter bed tank 820 to the downstream contact filter bed tank 830 is performed. realizable. It should be noted that at least one of the size (for example, the inner diameter D30), the height and the shape may be different among the plurality of second openings. For example, the second opening 300 at the height of FIG. 4 and the second opening 300 at the height of FIG. 11 may be formed in one partition wall. Similarly, at least one of size (eg, inner diameter D20), height and shape may differ among the plurality of first openings. Further, at least one of the size and the shape may be different between the first opening and the second opening.

In either case, the partition wall may be provided with one or more first openings having a lower end at a position lower than the reference water level LWL and an upper end at a position higher than the reference water level LWL. The partition wall may be provided with one or more second openings. Here, the one or more second openings are preferably the following openings. That is, with respect to the ease with which water flowing along the water surface WL (here, the reference water level LWL) is transferred from the contact filter bed tank 830 to the anaerobic filter bed tank 820 on the upstream side through the opening, the ease of advection of the second opening is. Less than the ease of advection of any one or more of the first openings.

Various configurations can be adopted as the respective configurations of the first opening and the second opening. For example, as one or more first openings provided in the partition wall, a lower end arranged at a position lower than a predetermined reference water level and an upper end arranged at a position higher than the reference water level are provided. Various openings having can be adopted. The water flowing along the water surface can be easily moved from the downstream treatment tank to the upstream treatment tank through such a first opening. Therefore, such a first opening can easily transfer the solid matter from the treatment tank on the downstream side to the treatment tank on the upstream side. The one or more second openings provided in the partition wall preferably include at least one of the following two types of openings.
(A) A low opening that is a position at a height below the reference water level and has an upper end arranged at a position lower than any of the upper ends of each of the first or more first openings. (B) A first or more first opening. It extends from a position lower than any of the lower ends of each opening to a position higher than the reference water level, and the width of the opening at the height of the reference water level is one or more of the first openings at the height of the reference water level, respectively. Narrow opening, which is an opening smaller than any of the widths of the water, is less likely to flow from such a second opening to the treatment tank on the upstream side than the first opening. This can result in a circulation in which water flows from the downstream treatment tank through the first opening to the upstream treatment tank and from the upstream treatment tank through the second opening to the downstream treatment tank. By such a flow of water, the solid matter can move from the treatment tank on the downstream side to the treatment tank on the upstream side through the first opening.

If the partition wall is formed with a plurality of openings having a lower end at a position lower than the reference water level LWL and an upper end at a height higher than the reference water level LWL, the reference among the plurality of openings. The opening having the widest opening at the height of the water level may be adopted as the first opening. That is, a plurality of openings provided in the partition wall (specifically, a treatment tank on the upstream side of the partition wall (anaerobic filter bed tank 820 in the example of FIG. 2) and a treatment tank on the downstream side (specifically, in the example of FIG. 2). , A plurality of openings communicating with the contact filter bed tank 830), the lower end arranged at a position lower than the predetermined reference water level, and the upper end arranged at a position higher than the reference water level. When including one or more openings (referred to as water level openings), the one or more first openings are one or more openings having the widest opening width at the reference water level height among the one or more water level openings. It's okay. Here, when the height of the upper end of the opening is the same as the height of the reference water level, the width of the upper end may be adopted as the width of the opening. Then, among the plurality of openings provided in the partition wall, the opening corresponding to the low opening and the opening corresponding to the narrow opening are seconded by using the widest first opening as a reference. It may be adopted as an opening. According to such a configuration, the solid matter can be appropriately transferred by using the first opening and the second opening. In the modification of FIG. 12, each of the two openings 200 corresponds to the widest first opening, and each of the two openings 300 corresponds to a low opening (ie, the second opening). Further, in the modified example of FIG. 12, the height of one opening 300 is the same as the height of the second opening 300 of FIG. 11, and the height of another opening 300 is the height of FIGS. 4 and 12. It may be the same as the height of the second opening 300 of. In this case, the height opening 300 of FIG. 11 corresponds to a narrow opening, and the height opening 300 of FIGS. 4 and 12 corresponds to a low opening. Each of the two openings 200 corresponds to the widest first opening.

When using the widest first opening as a reference, an opening that does not correspond to either a low opening or a narrow opening has a small effect on the transfer of solid matter using the first opening and the second opening. Is presumed to be. Such an opening may be treated as an opening that does not fall under either the first opening or the second opening. Thus, the one or more second openings may be configured at at least one of a low opening and a narrow opening.

Further, the one or more first openings provided in the partition wall include one or more openings having an upper end arranged at a position higher than the reference water level LWL, and further, one or more second openings provided in the partition wall. The openings may include one or more openings with an upper end located below the reference water level LWL. According to this configuration, the movement of solid matter through the first opening can be promoted. The one or more first openings having an upper end higher than the reference water level LWL may be a part or all of the one or more first openings provided on the partition wall. Further, the one or more second openings having an upper end lower than the reference water level LWL may be a part or all of the one or more second openings provided on the partition wall.

Further, each shape of one or more specific first openings of one or more first openings provided on the partition wall and one or more of one or more second openings provided on the partition wall are specified. Each shape of the second opening is a circular shape with the same inner diameter, and the center of each of one or more specific second openings is lower than any of the centers of one or more specific first openings. It may be placed in a position. According to this configuration, the first opening and the second opening that can promote the transfer of the solid matter through the first opening can be easily formed. The height of the center may be different between one or more specific second openings. Further, the one or more specific first openings may be a part or all of the one or more first openings provided in the partition wall. Further, the one or more specific second openings may be a part or all of the one or more second openings provided in the partition wall. Then, the upper end of each of the one or more specific first openings may be arranged at a position higher than the reference water level LWL, and the upper end of at least one first opening of the one or more specific first openings may be arranged. It may be arranged at the same height as the reference water level LWL. Further, the upper end of each of the one or more specific second openings may be arranged at a position lower than the reference water level LWL, and the upper end of at least one second opening of the one or more specific second openings may be arranged. It may be arranged at a position higher than the reference water level LWL.

In either case, if the plurality of first openings are provided on the partition wall, the plurality of first openings so as to sandwich one or more second openings with respect to the position in the horizontal direction. It is preferable that one opening and one or more second openings are arranged. Here, the fact that the two first openings sandwich the second opening with respect to the horizontal position means that the horizontal position of the second opening (particularly, the horizontal position parallel to the partition wall, for example, FIG. 12). In the modified example, it means that the position in the Y direction) is between the horizontal positions of the two first openings. According to this configuration, it is possible to prevent the solid matter that has moved upstream through one first opening from returning to the downstream side through the adjacent first opening. However, the two first openings may be arranged so as to line up in the horizontal direction without sandwiching the second opening.

Further, in any case, the shape of each of the one or more first openings is not limited to a circular shape, and may be various shapes. Similarly, the shape of each of the one or more second openings is not limited to the circular shape, and may be various shapes. For example, a shape arbitrarily selected from an ellipse and a polygon (for example, a triangle, a quadrangle, and an N-side polygon (N is an integer of 3 or more)) may be adopted. Further, the shape may be different among the plurality of first openings, and the shape may be different among the plurality of second openings. Further, the shape may be different between at least one first opening and at least one second opening. In general, the edge of the first opening may include at least one of a straight portion forming a linear edge portion and a curved portion forming a curved edge portion. Further, it is preferable that the edge of the first opening does not include a portion convex from the outside to the inside of the first opening, but includes a portion convex from the inside to the outside of the first opening. Similarly, the edge of the second opening may include at least one of a straight portion forming a linear edge portion and a curved portion forming a curved edge portion. Further, it is preferable that the edge of the second opening does not include a portion convex from the outside to the inside of the second opening, but includes a portion convex from the inside to the outside of the second opening.

(2) When viewed vertically downward, at least a part of the second opening 300 may overlap with the first opening 200. Further, in order to appropriately cause water circulation (FIG. 5) through the openings 200 and 300, it is preferable that the difference in the area of the portion below the reference water level LWL between the openings 200 and 300 is small. For example, of the area of the portion of the first opening 200 below the reference water level LWL and the area of the portion of the second opening 300 below the reference water level LWL, the larger area may be 300% or less of the smaller area. It is preferable that the larger area is 200% or less of the smaller area. When at least one of the total number of the first openings 200 and the total number of the second openings 300 is 2 or more, the total area of the portions of one or more first openings 200 below the reference water level LWL and one or more second openings. The total area of the portion of the opening 300 below the reference water level LWL, of which the larger area is preferably 300% or less of the smaller area, and the larger area is 200% of the smaller area. The following is particularly preferable.

(3) The configuration of the wastewater treatment apparatus may be changed to the configuration of the wastewater treatment apparatus 800 described above, and may have various other configurations. For example, instead of the settling separation tank 810, an anaerobic filter bed tank having a filter medium may be provided. Further, instead of the anaerobic filter bed tank 820, a settling separation tank in which the filter medium is omitted may be provided. Further, instead of the contact filter bed tank 830, a carrier flow tank in which the granular carrier flows may be provided.

Generally, the wastewater treatment device includes a plurality of treatment tanks including an anaerobic treatment tank and an aerobic treatment tank provided on the downstream side of the anaerobic treatment tank, and an air diffuser is provided in the aerobic treatment tank. The partition wall separating the anaerobic treatment tank and the aerobic treatment tank is provided with one or more openings 200 and one or more openings 300 for moving the solid material from the aerobic treatment tank to the anaerobic treatment tank. Is preferable.

The anaerobic treatment tank may be, for example, various anaerobic treatment tanks. For example, a settling separation tank in which the filter medium is omitted may be adopted. Further, the configuration of the first transfer pump for transferring the water in the anaerobic treatment tank to another treatment tank different from the anaerobic treatment tank and the aerobic treatment tank is different from the configuration of the sludge transfer air lift pump 910 described above. It may have various configurations. For example, instead of the air lift pump, another type of pump (for example, an electric pump that transfers water using an electric motor) may be adopted. Further, at least a part of the suction port of the first transfer pump (for example, the suction port 911 of the sludge transfer air lift pump 910) is the lower end 200d of each of the one or more first openings 200 provided in the partition wall, and the partition wall. It may be arranged at a position higher than the lowest lower end (referred to as "lowest lower end") of the lower end 300d of each of the one or more second openings 300 provided in the above. For example, in the embodiment of FIGS. 4, 11 and 12, the lower end 300d of the second opening 300 corresponds to the lowest lower end. Generally, the suction port of the first transfer pump is a portion lower than the lowest lower end of each lower end 200d of one or more first openings 200 and each lower end 300d of one or more second openings 300. It is preferable to include it. According to this configuration, the first transfer pump can easily transfer the solid matter settled at a position lower than the openings 200 and 300. When the edge of the suction port includes a portion lower than the lowermost lower end, it can be said that the suction port includes a portion lower than either the lower end 200d or 300d. The first transfer pump that transfers the water in the anaerobic treatment tank to another treatment tank may be omitted.

The configuration of the advection baffle provided in the anaerobic treatment tank may be various other configurations instead of the configuration of the advection baffle 823 described above. For example, at least a part of the lower opening 824 is arranged at a position higher than the lowest lower end of each lower end 200d of one or more first openings 200 and each lower end 300d of one or more second openings 300. It may have been done. In general, the lower opening 824 preferably includes a portion lower than the lowest lower end of each lower end 200d of one or more first openings 200 and each lower end 300d of one or more second openings 300. .. According to this configuration, the solid matter in the anaerobic treatment tank moves from the lower opening 824 into the advection baffle 823 without settling at the bottom of the anaerobic treatment tank, and flows out from the openings 200 and 300 to the aerobic treatment tank. You can suppress what you do. Further, the lower opening 824 of the advection baffle 823 may extend from a relatively low position to a relatively high position instead of a horizontal opening. For example, the bottom of the advection baffle 823 may be closed and a lower opening 824 may be formed on the side surface of the advection baffle 823. When the edge of the lower opening 824 includes a portion lower than the lowermost lower end, it can be said that the lower opening 824 includes a portion lower than either the lower end 200d or 300d. The advection baffle may be omitted.

The configuration of the introduction portion that guides the water flowing into the anaerobic treatment tank to the anaerobic treatment tank may be various other configurations instead of the configuration of the advection opening 814 described above. For example, water may be introduced into the anaerobic treatment tank through a pipe. In this case, the outlet of the pipe corresponds to the introduction. Generally, it is preferable that the lower end of the introduction portion is arranged at a position higher than the upper end 824u of the lower opening 824 of the advection baffle 823. According to this configuration, water flows downward from the introduction portion to the lower opening 824 of the advection baffle 823, so that the solid matter in the anaerobic treatment tank can be easily stored at the bottom of the anaerobic treatment tank. However, the lower end of the introduction portion may be arranged at a position lower than the upper end 824u of the lower opening 824 of the advection baffle 823.

The aerobic treatment tank may be various aerobic treatment tanks. For example, it may be a fluidized tank in which the carrier flows. Further, the air diffuser of the aerobic treatment tank may be for continuously dissipating air, or may be for intermittently dissipating air instead.

As the air diffuser provided in the aerobic treatment tank, any member capable of generating air bubbles can be adopted instead of the one in which the pipe is provided with a plurality of holes. For example, a porous air diffuser, a disk diffuser, or the like can be adopted. As the porous air diffuser, for example, a sintered air diffuser, a membrane type air diffuser, or the like can be adopted. Further, the total number of air diffusers provided in the aerobic treatment tank may be any number of 1 or more. When a plurality of air diffusers are provided, it is preferable that the plurality of air diffusers are arranged at different positions in the aerobic treatment tank when viewed vertically downward. Then, it is preferable that the plurality of air diffusers are connected to a distribution valve for adjusting the balance of air diffusers among the plurality of air diffusers. Then, the gas from the blower is preferably supplied to a plurality of air diffusers via this distribution valve. Thereby, the bias of the air diffuser among the plurality of air diffusers can be alleviated.

Further, the advection opening forming portion that forms an advection opening that limits the amount of water per unit time at the time of peak inflow, which is an advection opening that transfers water to the downstream side on the downstream side of the contact filter bed tank 830, is shown in FIG. Instead of the wall portion 859 of the disinfection tank 850 described in 2 and the like, various other members may be used. For example, a pipe connecting the treatment water tank 840 and the disinfection tank 850 may form an advection opening. In this case, the opening at the end of the pipe may correspond to the advection opening. Further, the advection opening is not limited to the opening that communicates the treatment water tank 840 and the disinfection tank 850, and may be an opening that communicates various other treatment tanks.

The partition wall forming the openings 200 and 300 is replaced with the partition wall connected to the outer wall of the wastewater treatment device (for example, the outer wall 801 of FIG. 3 (A)) as in the partition wall 829 of FIG. 3 (A). , Various partition walls may be used. For example, openings 200, 300 may be formed in the partition wall connected to both the outer wall of the wastewater treatment device and the other partition wall. Further, openings 200 and 300 may be formed in the partition wall which is connected to another partition wall without being connected to the outer wall of the wastewater treatment device. In addition to the first opening 200 and the second opening 300, other openings may be formed in the partition wall. However, it is preferable that the influence of the other openings on the transfer of the solid matter by the openings 200 and 300 is small.

Further, a downstream treatment tank, which is another treatment tank, may be provided on the downstream side of the aerobic treatment tank. The downstream treatment tank may be any treatment tank instead of the treatment water tank 840. For example, another aerobic treatment tank may be provided.

The configuration of the communication portion that communicates the aerobic treatment tank and the downstream treatment tank replaces the configuration of the opening 834 formed by the partition wall 839 that separates the contact filter bed tank 830 and the treatment water tank 840. It may have various other configurations. For example, the communication portion may be arranged at a position vertically upward from the bottom of the aerobic treatment tank. Further, the communication portion may be formed by a pipe. In either case, the water flow region formed by the communication portion is the lower end 200d of each of the one or more first openings 200 provided in the partition wall and the one or more second openings 300 provided in the partition wall. It is preferable to include a flow path lower than the lowest minimum lower end of each of the lower end 300d (that is, the communication portion includes a portion forming a flow path lower than the lowest lower end). According to this configuration, the solid matter settled at a position lower than either the lower end 200d or 300d in the aerobic treatment tank can be moved to the downstream treatment tank through the communication portion. Therefore, it is possible to prevent the amount of solid matter in the aerobic treatment tank from becoming excessive. For example, as in the embodiment of FIG. 2, when the entire advection opening 834 is lower than the lowest lower end (here, the lower end 300d), the area through which the water formed by the advection opening 834 flows (here, the advection opening 834). The entire part) forms a flow path lower than either the lower end 200d or 300d. Here, it is preferable that the communication portion forms a flow path in which the height of the bottom does not change from the bottom of the aerobic treatment tank to the bottom of the downstream treatment tank via the communication portion. According to this configuration, the movement of solid matter from the aerobic treatment tank to the downstream treatment tank through the communication portion can be promoted. The bottom of the communication portion may be arranged at a position higher than the lowest lower end.

Further, the configuration of the second transfer pump for transferring the water in the downstream treatment tank to another treatment tank different from the first, second and third treatment tanks is replaced with the configuration of the circulation air lift pump 920 described above. It may have various other configurations. For example, instead of the air lift pump, another type of pump (for example, an electric pump that transfers water using an electric motor) may be adopted. In either case, it is preferable that the suction port of the second transfer pump (for example, the suction port 921 of the circulation air lift pump 920) is arranged at the bottom of the downstream processing tank. According to this configuration, the second transfer pump can transfer the solid matter accumulated at the bottom of the downstream treatment tank to the outside of the downstream treatment tank. Generally, the suction port of the transfer pump is lower than the lowest lower end of each of the lower end 200d of one or more first openings 200 and the lower end 300d of each of one or more second openings 300. It is preferable to include it. According to this configuration, the second transfer pump can easily transfer solid matter existing at a position lower than the openings 200 and 300 in the downstream processing tank. However, the second transfer pump that transfers the water in the downstream treatment tank to another treatment tank may be omitted.

Although the present invention has been described above based on Examples and Modifications, the above-described embodiments of the invention are for facilitating the understanding of the present invention and do not limit the present invention. The present invention may be modified or improved without departing from the spirit and claims, and the present invention includes an equivalent thereof.

100 ... air supply tube, 110 ... first tube, 111, 112 ... tube, 120 ... second tube, 130 ... third tube, 200 ... first opening, 200c ... center, 200d ... lower end, 200u ... upper end, 300 ... first 2 openings, 300c ... center, 300d ... lower end, 300u ... upper end, 500 ... blower, 800 ... wastewater treatment device, 801 ... outer wall (tank body), 802 ... inlet, 804 ... discharge port, 807 ... air supply port, 810 ... Sedimentation separation tank, 811 ... Opening, 812 ... Inflow baffle, 814 ... Transfer opening (introduction part), 814d ... Lower end, 819 ... Partition wall, 820 ... Anaerobic filter bed tank, 821 ... First part, 822 ... Second part , 823 ... Transfer baffle, 824 ... Lower opening, 824d ... Lower end, 824u ... Upper end, 825 ... Upper opening, 826 ... Filter material, 827b ... Lower end, 829 ... Partition wall, 830 ... Contact filter bed tank, 832 ... Contact material, 834 ... transfer opening (communication part), 836 ... contact material, 838a ... first air diffuser, 838b ... second air diffuser, 838v ... three-way valve (distribution valve), 839 ... partition wall, 840 ... treatment water tank, 850 ... Disinfection tank, 852 ... transfer opening (inlet), 854 ... overflow opening, 856 ... chemical cylinder, 859 ... wall, 900 ... wastewater treatment system, 910 ... sludge transfer air lift pump, 910v ... adjustment valve (transfer valve), 911 ... Suction port, 912 ... Outlet, 920 ... Circulation air lift pump, 920v ... Adjustment valve (circulation valve), 921 ... Suction port, 922 ... Outlet, 1000 ... Test tank, H ... Water depth, G1, G2 ... Bubbles, D1 ... 1st distance, D2 ... 2nd distance, W2 ... width, UF ... upward flow, DF ... downward flow, WL ... water level (water surface), LWL ... low water level (reference water level), HWL ... high water level, SS ... solid matter, D20, D30 ... inner diameter, W1a, W1b ... width

Claims (4)

It is a wastewater treatment device
A plurality of treatment tanks including an anaerobic treatment tank and an aerobic treatment tank provided on the downstream side of the anaerobic treatment tank.
A partition wall separating the anaerobic treatment tank and the aerobic treatment tank,
The air diffuser provided in the aerobic treatment tank and
A transfer pump that transfers the water in the anaerobic treatment tank to another treatment tank different from the anaerobic treatment tank and the aerobic treatment tank among the plurality of treatment tanks.
An advection opening forming portion provided on the downstream side of the aerobic treatment tank and forming an advection opening for transferring water to the downstream side.
Equipped with
The partition wall is a plurality of openings communicating the anaerobic treatment tank and the aerobic treatment tank, and has a plurality of openings including one or more first openings and one or more second openings.
Each of the one or more first openings has a lower end arranged at a position lower than a predetermined reference water level and an upper end arranged at a position higher than the reference water level.
The first or more second openings are
A low opening which is a position at a height below the reference water level and has an upper end arranged at a position lower than any of the upper ends of each of the above-mentioned first openings.
The width of the opening at the height of the reference water level is the height of the reference water level, extending from a position lower than any of the lower ends of each of the first or more first openings to a position higher than the reference water level. A narrow opening, which is an opening smaller than any of the widths of each of the above-mentioned one or more first openings in the above.
Including at least one of
The anaerobic treatment tank
A portion of the anaerobic treatment tank located at a position lower than the lowest end of the lower end of each of the one or more first openings and the lower end of each of the first or more second openings. A baffle that forms a third opening including the third opening and communicates the third opening with the first opening and the second opening.
The introduction section for guiding the water flowing into the anaerobic treatment tank to the anaerobic treatment tank, wherein the lower end of the introduction section is arranged at a position higher than the upper end of the third opening.
Equipped with
The transfer pump has a suction port including a portion located at a position lower than the lowermost end.
The size of the advection opening is such that the advection opening is transferred when the amount of water flowing into the wastewater treatment apparatus per unit time is temporarily increased by the peak inflow preliminarily associated with the wastewater treatment apparatus. The water level between the anaerobic treatment tank and the aerobic treatment tank is temporarily raised by limiting the amount of water to be applied per unit time to a smaller amount than the amount of the peak inflow per unit time. Has been
The reference water level, the lower end of each of the one or more first openings, and the lower end of each of the one or more second openings are arranged at positions higher than the air diffuser.
Wastewater treatment equipment. The wastewater treatment apparatus according to claim 1.
The transfer pump is an air lift pump.
Wastewater treatment equipment. The wastewater treatment apparatus according to claim 1 or 2.
The other treatment tank, which is different from the anaerobic treatment tank and the aerobic treatment tank, is a treatment tank provided on the upstream side of the anaerobic treatment tank.
The plurality of treatment tanks include a downstream treatment tank which is a treatment tank on the downstream side of the aerobic treatment tank.
When the transfer pump is referred to as a first transfer pump, the wastewater treatment device includes a second transfer pump that transfers water in the downstream treatment tank to the other treatment tank.
Wastewater treatment equipment. The wastewater treatment apparatus according to any one of claims 1 to 3.
The advection opening forming portion further forms an advection opening arranged at a position higher than the advection opening.
Wastewater treatment equipment.

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