JPH02122891A - Aerobic waste water treatment equipment - Google Patents

Abstract

PURPOSE:To obtain an aerobic waste water treatment equipment capable of treating water to be treated at a high degree at low cost by partitioning a solid-liquid separation reaction tank into a precipitation region, a contact aeration region and an organism filtration region with the wall bodies and arranging a contact material to the insides of these regions of precipitation, contact aeration and organism filtration respectively. CONSTITUTION:Waste water is discharged to the bottom part of a precipitation region 1 from the lower end of a draft tube 23 and dispersed. This waste water is introduced into the upper part of the inside of a contact aeration region 2 in which suspended solid in waste water is precipitated and separated. Oxygen- contg. gas is blown into waste water through a diffuser 12 and thereby aerobic microorganisms in waste water are activated. The dissoluble residual substance in waste water is biodegraded and nitrogen is nitrated. In an organism filtration region 3, SS in waste water is stuck on the surface of a contact material 8 and also waste water is filtered by the action of microorganisms stuck on the surface thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an aerobic wastewater treatment device that performs advanced treatment of organic wastewater.

``Prior art'' Conventionally, in the case of a fluidized bed for aerobically treating organic wastewater, suspended particles with biofilm attached, microorganism-entrapping immobilization gel, etc. are used inside the reactor for wastewater treatment. Microorganisms are introduced into the system, suspended, and fluidized to perform wastewater treatment. In this wastewater treatment method using a fluidized bed reactor (hereinafter referred to as the fluidized bed method), the wastewater treatment speed is extremely fast, and it also causes a bulking phenomenon that makes sedimentation and separation of sludge difficult. It has the advantage of being difficult.

However, in the treated water treated by such a fluidized bed method, a large amount of suspended solids (hereinafter referred to as SS) such as microbial flocs, which are generally difficult to separate by sedimentation, are mixed in. After primary treatment using the fluidized bed method,
The secondary treated water is further poured into a sedimentation tank and subjected to secondary treatment in the sedimentation tank to precipitate the SS in the secondary treatment water.

"Problem to be Solved by the Invention" However, in the above-mentioned sedimentation tank, SS is removed only by the difference in specific gravity with water, so it is difficult to remove fine SS, colloidal substances, etc. In the above fluidized bed method, when suspended particles with attached biofilms, microorganism entrapping immobilization gel, etc. are used as microorganisms, sedimentation due to the cohesive force of the microorganisms mixed into the treated water may occur. There was a problem that SS in the treated water was not sufficiently sedimented and separated because of the low water quality, making it impossible to obtain treated water of good quality. In addition, in order to improve the water quality of the treated water treated in the above sedimentation tank, a flocculant is further added to the treated water and SS
In some cases, the water is separated by precipitation, but in that case, there is a problem that the treatment cost increases because the flocculant is expensive.Furthermore, the treated water is sometimes treated with a membrane, but in this case, electricity is required. There are problems such as high costs.

However, when secondary treatment is carried out using the fluidized bed method, the amount of suspended sludge in the secondary treatment water that is introduced into the settling tank is extremely small compared to the activated sludge method (for example, when treating domestic wastewater, The final floating sludge in the next treatment water is 2000 to 4000rn9/Q in the case of activated sludge, while it is 40 to 90my/Q in the fluidized bed, which is a biofilm method.), from the settling tank to the fluidized bed. Since there is no need to return the sludge, there is an excellent advantage that the area load of solids on the sedimentation tank is significantly smaller than that in a sedimentation tank using the activated sludge method. Therefore, in order to take advantage of such excellent advantages of the fluidized bed method, there is a demand for an advanced treatment device that includes solid-liquid separation and can effectively treat secondary treated water treated by the fluidized bed method.

This invention was made in view of the above circumstances, and is suitable for treating secondary treated water with a small amount of hand sludge, such as treated water treated in a fluidized bed, and is suitable for treating such treated water. The purpose of the present invention is to provide an aerobic wastewater treatment device that can perform advanced treatment at low cost.

[Means for Solving the Problems j] A first aerobic wastewater treatment device of the present invention is an aerobic wastewater treatment device for treating organic wastewater by solid-liquid separation in a solid-liquid separation reaction tank. The reaction tank is partitioned by a wall into a precipitation area, a contact aeration area, and a biological filtration area, and a contact material is placed inside each of the precipitation area, contact aeration area, and biological filtration area, and air is supplied to the contact aeration area. A diffuser pipe is arranged to aerate by blowing oxygen-containing gas such as, etc., and a draft tube is arranged to introduce wastewater from the top to the bottom into the settling area, and the wastewater in the settling area is contact aerated in the upper part of the settling area. A communication part is provided at the lower part of the wall that partitions the contact aeration area and the biological filtration area, and a communication part is provided at the lower part of the wall that partitions the contact aeration area and the biological filtration area, and the wastewater in the biological filtration area is connected to the sedimentation area in the upper part of the biological filtration area. A circulation device is connected to the biological filtration area to circulate it back to the biological filtration area, and an outflow portion is provided to allow part of the wastewater in the biological filtration area to flow out.

A second aerobic wastewater treatment apparatus of the present invention is the first aerobic wastewater treatment apparatus described above, except that a sludge separation plate is provided at the lower part of the draft tube and slopes downward outside the draft tube.

A third aerobic wastewater treatment device of the present invention is the first aerobic wastewater treatment device, in which an overflow weir lower than the upper end of the wall is provided on the wall that partitions the settling region and the contact aeration region. It is something.

A fourth aerobic wastewater treatment device of the present invention is the first aerobic wastewater treatment device described above, in which an overflow weir lower than the upper end of the wall of the biological filtration region is provided on the wall of the biological filtration region.

A fifth aerobic wastewater treatment device of the present invention is the first aerobic wastewater treatment device, in which a container-shaped submerged weir is buried in the wastewater in the upper part of the biological filtration area to store the wastewater. A circulation device for circulating the wastewater in the submerged weir to the settling area is connected to the submerged weir.

A sixth aerobic wastewater treatment device of the present invention is the first aerobic wastewater treatment device, in which the contact material in each region is arranged such that the voids become smaller in the order of the sedimentation region, the contact aeration region, and the biological filtration region. It is filled.

A seventh aerobic wastewater treatment device of the present invention is the first aerobic wastewater treatment device, in which backwashing air piping for backwashing is arranged below the contact material in each region, and A hopper section is provided at the bottom of the area, and the side wall is inclined inward to reduce the bottom area, and a sludge pulling mechanism is provided at the bottom of the hopper section.

An eighth aerobic wastewater treatment device of the present invention is the first aerobic wastewater treatment device, in which a sludge return mechanism is provided in the contact aeration region and the biological filtration region to return the sludge accumulated at the bottom of each region to the settling region. It was established.

"Operation" When treating wastewater using the first aerobic wastewater treatment apparatus of the present invention, first, raw wastewater is introduced into the settling region from the upper end of the draft tube. In this way, the wastewater flows out from the lower end of the draft tube to the bottom of the settling area and is dispersed, and the suspended solids (hereinafter referred to as SS) in the wastewater are separated by precipitation, and the surface of the contact material is It passes through and rises while depositing SS on its surface. The wastewater that has reached the upper part of the settling area flows out from the upper part into the contact aeration area, and within this contact aeration area, it passes through the surface of the contact material and descends while adhering ss to the surface. To go. At the same time, within this contact aeration area,
By blowing oxygen-containing gas into the wastewater from the aeration tube, aerobic microorganisms in the wastewater are activated to biodegrade soluble residual substances in the wastewater, and the nitrogen content is nitrified by the oxygen-containing gas. The wastewater that has reached the lower part of the contact aeration zone in this way flows out through the connection into the biological filtration zone, where it rises through the surface of the contact material and is thus The SS inside adheres to the surface of the contact material, and the wastewater is filtered and further decomposed by the action of microorganisms adhering to the surface. A considerable portion of the wastewater that has reached the upper part of the biological filtration area in this way is returned to the sedimentation area by the circulation device and circulated through each area, and after the water quality has been sufficiently improved, it is passed through the biological filtration area. The treated water flows out from the top of the area to the outside. Therefore, the wastewater comes into contact with the aerobic organisms attached to the surface of the contact plate many times in each area, which causes SS precipitation and adhesion separation.
Biodegradation of soluble substances, nitrification of nitrogen content, etc. are performed efficiently, and wastewater is highly treated in a short time.

In the second aerobic wastewater treatment apparatus of the present invention, an inclined plate is provided at the lower part of the draft tube and is inclined downward outside the draft tube, so that the inclined plate allows the vertical flow of wastewater in the settling region. This reduces the sludge in the wastewater and prevents it from floating upward, and even if sludge is placed on the sloped plate, it easily slides down due to the slope, so the sludge in the settling area is effectively removed. It will precipitate and accumulate at the bottom, thereby increasing wastewater treatment efficiency.

In the third aerobic wastewater treatment device of the present invention, an overflow weir lower than the upper end of the wall that partitions the settling region and the contact aeration region is provided, so that part of the wastewater in the settling region is Since the supernatant that has passed over the overflow weir flows into the contact aeration area, the SS in the settling area is blocked by the overflow weir and cannot flow out to the contact aeration area. The inflow of SS into the area will be suppressed to a minimum. Therefore, the contact materials in the contact aeration area and the biological filtration area are less likely to be clogged, and the backwashing cycle can be lengthened.

In the fourth aerobic wastewater treatment device of the present invention, an overflow weir lower than the upper end of the outer wall is provided on the outer wall of the biological filtration region, so that the wastewater in the biological filtration region exceeds the overflow weir. The supernatant will flow out as treated water. Therefore, the flow of wastewater generated as the treated water flows out is blocked by the overflow weir and suppressed to a low level, thereby preventing the SS from peeling off from the contact material, and also preventing the flow of wastewater from the upper part of the biological filtration area. Even if a very small amount of SS remains in the water, the overflow weir prevents the SS from flowing out, thereby improving the quality of the treated water.

In the fifth aerobic wastewater treatment device of the present invention, a container-shaped submerged weir is disposed in the upper part of the biological filtration area to store wastewater while being buried in the wastewater, and the submerged weir is placed in the submerged weir. By connecting a circulation device that circulates the wastewater inside the biological filtration tank to the sedimentation area, the upward flow inside the biological filtration tank is equalized, and at the same time, the flow of wastewater generated as the circulating water flows out is blocked by the submerged weir. As a result, even when the amount of circulating water is increased appropriately, peeling of SS from the contact material can be suppressed to a minimum. For this reason, it becomes possible to increase the amount of circulating water and improve the treatment efficiency of wastewater, and the wastewater is highly processed in a short time and the quality of the treated water is improved.

In the sixth aerobic wastewater treatment apparatus of the present invention, each region was filled with contact material so that the voids became smaller in the order of precipitation region, contact aeration region, and biological filtration region. For this reason,
In the sedimentation region, large voids capable of holding a large amount of SS are formed in each contact material, and the solid-liquid separation and sludge retention capabilities of the sedimentation region are improved, and the wastewater treatment capacity of the wastewater treatment equipment as a whole is also improved. In addition, in the biological filtration area, the wastewater flow path between each contact material becomes narrower, and the biofilm forming surface on the contact material surface increases, and the wastewater comes into sufficient contact with the biofilm, increasing filtration efficiency. That will happen.

In the seventh aerobic wastewater treatment device of the present invention, backwashing air piping for backwashing is arranged below the contact material in each region, and the side walls are inclined inward at the bottom of each region. By providing a hopper section with a reduced bottom area and a sludge pulling mechanism at the bottom of the hopper section, when air is blown onto the contact material through the backwashing air piping, The sludge adhering to the contact material falls into the hopper section, and due to the slope of the side wall, the sludge that has fallen into the hopper section slides down to the bottom section and is smoothly pulled out from the bow extraction mechanism.

In the eighth aerobic wastewater treatment apparatus of the present invention, a sludge return mechanism is provided in the contact aeration region and the biological filtration region to return the sludge accumulated at the bottom of each region to the settling region, thereby reducing the amount of excess sludge generated. The entire amount of sludge can be extracted from the sedimentation region, thereby allowing the generated excess sludge to be extracted in a concentrated state.

"Embodiment" An embodiment of the present invention will be described below with reference to FIG.

In the aerobic wastewater treatment apparatus of this embodiment, a solid-liquid separation reaction tank for performing solid-liquid separation of organic wastewater is partitioned by a wall 4.5 into a precipitation region 1, a contact aeration region 2, and a biological filtration region 3, These sedimentation area 1, contact aeration area 2, biological filtration area 3
A contact material 6.7.8 is filled inside each of the contact materials 6.7.8, and a plurality of backwash air pipes 9.10.11 extending horizontally below each contact material 6.7.8 are arranged in parallel. , a plurality of aeration pipes 12 for aerating by blowing oxygen-containing gas such as air under the contact material 6 in the contact aeration area 2 are arranged in parallel with and slightly above the backwashing pipe 9. Furthermore, an outflow section 13 is provided in the upper part of the sedimentation area 1 to allow the wastewater in the sedimentation area 1 to flow out to the contact aeration area 2, and the contact aeration area 2 and the biological filtration area 3 are connected to each other. A communication part 14 is provided at the lower part of the wall 5 that partitions the biological filtration area 3, and a circulation device 15 is connected to the upper part of the biological filtration area 3 to circulate the wastewater in the biological filtration area 3 back to the sedimentation area 1. An outflow portion 16 is provided for allowing a portion of the wastewater in the biological filtration area 3 to flow out to the outside.

The contact material 6.7.8 of each area above is the receiver 17.18.1
Supported by 9. The contact material 6 occupies a volume corresponding to 20 to 60% of the entire precipitation region 1. On the other hand, in the contact aeration zone 2 and the biological filtration zone 3, the contact material 7.8 accounts for 50-75%. These contact materials 6.7.8 are air-washed (backwashed) about once every 2 to 30 days by the backwash air piping 9.10.11. In addition, each of the contact materials 6.7.8, which are provided in plurality in each of the above regions, has voids in the precipitation region 1, contact aeration region 2,
The biological filtration area 3 is filled in such a way that the porosity becomes smaller in order, and the porosity is larger in the previous stage.In particular, in the sedimentation area 1, by setting the porosity to 90% or more, The space for holding SS adhesion is large.For this reason, the biological filtration area 3 is clogged more slowly than in the conventional case where the biological filtration area 3 is used directly for the purpose of solid-liquid separation and removal of soluble substances. Therefore, the frequency of backwashing, which was conventionally performed approximately once every 0.5 to 3 days, can be reduced to 1/1 or less.

The specific contact material filled in each region is, for example, a cylindrical material with a rectangular cross section, which is made up of walls made of intertwined string-like bodies made of polyethylene, etc., as shown in Fig. 2. (hereinafter referred to as contact material S) is used. A large number of such cylindrical contact materials S are filled in each region, and each region is filled in a different state. That is, the sedimentation area 1 and the biological filtration area 3 are filled in an upright state, and the contact aeration area 2 is filled in a horizontal state, and the inside of the contact material S filled in the biological filtration area 3 is , as shown in FIG. 3, is filled with irregularly shaped granular material K made by crushing oyster shells or minerals.

The precipitation area 1, contact aeration area 2, and biological filtration area 3 are as follows:
At the bottom thereof, hopper parts 20, 21, 22 are formed, each of which has side walls that are inclined inward to reduce the area of the bottom. Of the hopper sections in each of these regions, the hopper part 20 in the sedimentation region 1, where sludge is particularly frequently drawn, has a side wall with a steep slope of about 600 degrees with respect to the horizontal. The hopper sections 21, 22 of the contact aeration zone 2 and the biological filtration zone 3, in which sludge is withdrawn only during washing, have side walls inclined with a slope of 25 to 400 degrees.

A draft tube 23 is erected in the central part of the inside of the sedimentation area 1, and the upper end of this draft tube 23 is located slightly above the water surface of the wastewater, and the lower end is located at the upper end of the hopper part 20. It is located near the department. and,
A raw waste water supply pipe 25 for supplying raw waste water from above is inserted inside the draft tube 23, and an inclined plate 24 that slopes downward outside the draft tube 23 is provided at the lower part of the draft tube 23. ing.

This inclined plate 24 is configured so that the sludge can settle well due to its inclined surface, and also prevents the sludge settled at the bottom from being rolled up due to the inflow of circulating water, etc. However, in addition to the structure shown in FIG. 1, the inclined plate 24 may have a structure in which inclined plates are laminated.

In addition, a sludge extraction pipe 2 is provided at the bottom of the hopper section 20.
6 is connected, and this sludge extraction pipe 26 has a valve 2.
7 is provided.

The outflow part 13 that drains the wastewater in the settling area 1 to the contact aeration area 2 is provided with an overflow lower than the upper end of the wall 4 on the settling area 1 side of the wall 4 that partitions the settling area 1 and the contact aeration area 2. A container-shaped waste water reservoir 29 is formed between the overflow base 28 and the wall 4, and the overflow base 28 is provided on the upper part of the wall 4 that forms the wall of the waste water reservoir 29. The configuration is such that an outlet 30 is provided through which the wastewater in the sedimentation area 1 that has flowed into the wastewater reservoir 29 beyond the base 28 flows out into the contact aeration area 2.

The circulation device 15 includes a circulation pipe 31 and a circulation pipe 31.
One end of the circulation pipe 31 is connected to a submerged weir 33 provided in the upper part of the biological filtration area 3, and the other end is connected to the submerged weir 33 provided in the upper part of the biological filtration area 3. It is connected to the circulating water discharge pipe 40 inside. This circulating water discharge pipe 40 is arranged horizontally so as to be located between the backwash pipe 9 and the contact material 6 in the sedimentation area 1, and has a discharge port 41 that opens upward.
A plurality of are formed at predetermined intervals.

The circulation pump 32 is a special screw-type pump configured by providing a screw in piping, and is capable of circulating wastewater with extremely low power consumption. Further, the submerged weir 33 is formed in the shape of a container, and is buried in wastewater with an upward opening. The circulation piping 31 is connected.

The outflow portion 16 that allows part of the wastewater in the biological filtration area 3 to flow out is connected to the outer wall 35 of the biological filtration area 3.
An overflow base 36 lower than the upper end of 5 is provided, and a container-shaped waste water reservoir 37 is formed between this overflow base 36 and the outer wall 35,
An outflow port 38 is provided at the upper part of the outer wall 35 that forms the wall of this wastewater reservoir 37, through which the wastewater in the biological filtration area 3 that has flowed into the wastewater reservoir 37 over the overflow base 36 flows out to the outside. A treated water outflow pipe 39 is connected to the outflow port 38.

Further, at the bottom of each hopper section 21.22 of the contact aeration area 2 and biological filtration area 3, each hopper section 21.
．． A sludge return pipe 42.43 for returning the sludge accumulated in 22 to the settling area 1 is connected to the sludge return pipe 42.4.
3 is inserted into the draft tube 23 of the precipitation area 1 from above. And each sludge return pipe 42
．． 43 are each provided with a valve 44.45 and a sludge return pump 46.47.

When treating organic wastewater using such an aerobic wastewater treatment device, organic wastewater that has been previously treated in a fluidized bed reactor is used as raw wastewater, and the raw wastewater is passed through the raw wastewater supply pipe 25.
and into the draft tube 23. In this way, the wastewater flows out from the lower end of the draft tube 23 to the bottom of the settling area 1 and is dispersed, and the suspended solids (hereinafter referred to as SS) in the wastewater are separated by precipitation, and the surface of the contact material and rises while adhering SS to its surface. The wastewater that has reached the upper part of the settling area in this way flows out over the overflow base 28 into the wastewater sump 29 and then through the outlet 30 into the upper part of the contact aeration area 2.

The wastewater thus flowing into the upper part of the contact aeration area 2 passes through the surface of the contact material 7 and descends while adhering SS to the surface. At the same time, this contact aeration area 2
In this method, by blowing oxygen-containing gas into the wastewater from the aeration pipe 12, aerobic microorganisms in the wastewater are activated and soluble residual substances in the wastewater are biodegraded, and nitrogen bones are destroyed by the oxygen-containing gas. Nitrify.

The wastewater that has reached the lower part of the contact aeration area 2 in this way flows out into the biological filtration area 3 through the communication part 14, and within this biological filtration area 3, it passes through the surface of the contact material 8 and rises. As a result, SS in the wastewater adheres to the surface of the contact material 8, and the wastewater is filtered by the action of microorganisms adhering to the surface.

Most of the wastewater that has reached the upper part of the biological filtration area 3 in this way is returned to the sedimentation area 1 by the circulation device 15 and circulated through each area, so that the water quality is sufficiently improved, and at the same time, A part of it flows from the upper part of the biological filtration area 3 over the overflow weir 36 to the wastewater reservoir 37,
This flows out as treated water from the outlet 38 through the treated water outlet pipe 39 to the outside. In this case, the flow rate of the circulating water to be circulated to the precipitation region 1 is set in a range of 0.5 to 5 times, preferably 1 to 3 times, the flow rate of the raw wastewater.

According to this aerobic wastewater treatment device, the contact material 6.7.8 is filled in the precipitation area 1, the contact aeration area 2, and the biological filtration area 3 so that the voids become smaller in this order, and the wastewater is circulated through these areas. Therefore, in the settling region 1, by forming large voids capable of holding a large amount of SS between each contact material 6, the solid-liquid separation ability and tη mud holding ability of the settling region 1 are improved. In addition, in the biological filtration region 3, the wastewater flow path between each contact material 8 can be narrowed and the surface area of the contact material 8 can be increased. As a result, the wastewater can be brought into sufficient contact with the surface of the contact material 8, and the filtration efficiency can be improved. In addition, since SS can be held at an appropriate ratio in each region 1.2.3, the frequency of backwashing of the solid-liquid separation reaction tank as a whole can be reduced, and the hopper section 20.2. .22, the excess sludge was transferred to the sedimentation area 1, the contact aeration area 2, and the biological filtration area 3 in the order of 70~
It can be captured at a rate of 90%, 5-15%, and 2-5%. During backwashing, the sludge accumulated in the hopper sections 21.22 of the contact aeration area 2 and biological filtration area 3 is transferred to the sludge return pipe 42.43 and the sludge return pump 46.
47, it can be returned to the precipitation area l.
Excess sludge generated in each area can be extracted entirely from the settling area, and thereby the excess sludge can be extracted in a concentrated state.

In addition, here, to explain the replacement of surplus sludge and backwash sludge, backwash of settling area 1 is performed regularly,
It is pulled out along with the sludge accumulated in the hopper section 20. and,
The accumulated sludge in the settling area 1 is also periodically pulled out using a timer or the like. In addition, backwashing of the contact aeration area 2 and biological filtration area 3 is carried out using a raw water pump that supplies raw water to the secondary treatment tank in the previous stage during times when there is no inflow of raw water and the water level in the preparation tank is low, such as at night. Stop the water to prevent water from flowing into the device, and then lower the water level in the two-head area 2.3 slightly (to the extent that treated water does not overflow during backwashing).

(Left below) "Experiment example" The treatment process of wastewater treatment method 1 using the above aerobic wastewater treatment equipment and the treatment process of conventional wastewater treatment method H which has the same level of treatment effect as that wastewater treatment method. flow 1
, shown in flow 2.

(Flow I) (Fluidized bed) → Solid-liquid separation reaction tank Note: The solid-liquid separation reaction tank is divided into three areas: a precipitation area, a contact aeration area, and a biological filtration area.

(Flow 2) (Fluidized bed) → Sedimentation tank 1 → Contact aeration tank - Sedimentation tank 2 → Filtration tank Also, domestic wastewater is treated by the above wastewater treatment method I and wastewater treatment method ■, and the required amount for each wastewater treatment method is The times were measured and shown in Table 1. In addition, the treated water obtained by each of these wastewater treatment methods has BOD<7-8 R9/Q.

ss<2~31W/Q It is.

Table 1 However, in this table, the residence time of the filtration tank includes the space occupied by accessory equipment such as surrounding piping, which is converted into residence time.

As a result of comparing the time required for each wastewater treatment method in this way, it was found that wastewater treatment method I using the aerobic wastewater treatment device of the present invention has a simpler treatment process and shorter treatment time. I understand.

"Effects of the Invention" According to the aerobic wastewater treatment apparatus of the present invention, a solid-liquid separation reaction tank for performing solid-liquid separation of organic wastewater is partitioned by a wall into a precipitation region, a contact aeration region, and a biological filtration region, A contact material is placed inside each of the precipitation area, contact aeration area, and biological filtration area, and an aeration pipe for blowing oxygen-containing gas such as air into the contact aeration area for aeration is placed. A draft tube is arranged to introduce wastewater from the top to the bottom, and an outflow section is provided at the top of the settling area to allow the wastewater in the settling area to flow out into the contact aeration area, and to connect the contact aeration area and the biological filtration area. A communication part is provided at the lower part of the partitioning wall, and a circulation device is connected to the upper part of the biological filtration area to circulate the wastewater in the biological filtration area back to the sedimentation area, and also to circulate the wastewater in the biological filtration area. An outflow section is provided to allow a portion of the wastewater to flow out to the outside, so that the wastewater circulates through each of the areas mentioned above.■ Promoting contact between the wastewater and biofilm and preventing uneven flow by maintaining a certain flow rate. It can have excellent effects such as promoting biological treatment, ■ promoting nitrification, ■ preventing scum due to denitrification in the sedimentation area, and ■ preventing anaerobic elution of N H and -H from sludge. As a result, advanced treatment of organic wastewater can be performed efficiently in a short time, and costs can also be kept low.

According to the second aerobic wastewater treatment device of the present invention, since the inclined plate is provided at the lower part of the draft tube and is inclined downwardly outside of the draft tube, this inclined plate allows the vertical direction of the wastewater in the settling region to be The tlL force can be alleviated, thereby preventing the sludge from floating upward in the wastewater, and the slope can promote the sliding of the sludge, and the sludge in the settling area can be effectively removed. can be precipitated and accumulated at the bottom, thereby increasing wastewater treatment efficiency.

According to the third aerobic wastewater treatment device of the present invention, since the wall that partitions the settling region and the contact aeration region is provided with an overflow base lower than the upper end of the wall, part of the wastewater in the settling region is The supernatant that has passed through the overflow group can be allowed to flow out into the contact aeration area, thereby suppressing the flow accompanying the outflow of wastewater in the settling area and preventing the SS from peeling off from the post-catalyst material. Therefore, excessive SS does not flow into the contact aeration area, which makes it possible to lengthen the cycle for backwashing, thereby improving wastewater treatment efficiency.

According to the fourth aerobic wastewater treatment device of the present invention, since the overflow base is provided on the outer wall of the biological filtration area and is lower than the upper end of the outer wall, the wastewater in the biological filtration area exceeds the overflow base. The supernatant can be discharged outside as treated water. Therefore, it is possible to suppress the flow of wastewater that occurs with the outflow of treated water and prevent the SS from peeling off from the contact material in the biological filtration area. Even if only a small amount of 88 minutes remains, the overflow base can prevent that 88 minutes from flowing into the waste water reservoir, thereby improving the quality of the treated water.

According to the fifth aerobic wastewater treatment device of the present invention, a container-shaped submerged weir is disposed at the upper part of the biological filtration area so as to be buried in the wastewater and collect wastewater, and the submerged weir is placed in the submerged weir. By connecting a circulation device that circulates the wastewater in the weir to the sedimentation area, it is possible to equalize the upward flow in the biological filtration area, and also to direct the flow of wastewater generated as the circulating water flows to the submerged weir. This can minimize the separation of SS from the contact material even when the amount of circulating water is increased.For this reason, the amount of circulating water can be increased appropriately. The efficiency of wastewater treatment can be increased, wastewater can be highly treated in a short time, and the quality of treated water can be improved.

According to the sixth aerobic wastewater treatment device of the present invention, the contact material in each region is filled so that the voids become smaller in the order of the precipitation region, the contact aeration region, and the biological filtration region, so that in the precipitation region, By forming large voids that can hold a large amount of SS between each contact material, the solid-liquid separation ability and sludge holding ability of the settling region are improved, and the wastewater treatment ability of the entire wastewater treatment device is also improved. In addition, in the biological filtration region, the wastewater flow path between each contact material can be narrowed and the surface area of the contact material can be increased, so that the wastewater can be brought into sufficient contact with the surface of the contact material. , filtration efficiency can be increased.

According to the seventh aerobic wastewater treatment device of the present invention, backwashing air piping for backwashing is arranged below the contact material in each area, and the side wall is arranged inwardly at the bottom of each area. A hopper section with a sloped shape that reduces the area of the bottom is provided, and a sludge pulling mechanism is also provided at the bottom of this hopper section, so that air is not violently blown onto the contact material by the backwashing air piping. By making it flow, the sludge that is in the contact material can be dropped into the hopper section, and the sludge that has fallen into the hopper section can be slid down to the bottom section due to the slope of the side wall, thereby removing excess sludge. It can be pulled out smoothly from the pull-out mechanism.

According to the eighth aerobic wastewater treatment device of the present invention, a sludge return mechanism is provided in the contact aeration region and the biological filtration region to return the sludge accumulated at the bottom of each region to the settling region, so that excess sludge generated can be pulled out. All of this can be done from the settling area, which allows the excess sludge generated to be drawn out in a concentrated state.

[Brief explanation of drawings]

1 to 3 are diagrams showing an embodiment of the present invention, in which FIG. 1 is a schematic cross-sectional view of an aerobic wastewater treatment device, FIG. 2 is a schematic cross-sectional view of a contact material, and FIG. The figure is a schematic diagram of a contact material filled with granules. ■...Sedimentation area, 2...Contact aeration area, 3...Biological filtration area, 4.5...Wall body, 6.7.8... ...Contact material 9.10.11... Air piping for backwashing, 12...
...Water pipe, 13...Outflow part, 14...Communication part, 5...Circulation device, 6...Outflow part, 7.18.19 ...Receiver, 0121,22...Hopper section, 3...
Draft tube, 4... Inclined plate, 5... Raw wastewater supply pipe, 6.27... Sludge drawing mechanism, 8...
・Overflow weir, 9...Wastewater reservoir 0...Outlet, 1...Circulation piping, 2...Circulation pump, 3...・Underwater weir, 4.35... Outer wall, 6... Overflow weir, 7... Waste water reservoir, 8... Outlet, 9... ... Treated water outflow pipe, 0 ... Circulating water discharge pipe, 41 ... Discharge port, 42.44.46 ... Sludge return mechanism, 43.4
5.47...Sludge return mechanism, S...Contact material, K...Particulate matter.

Claims (8)

[Claims] (1) In an aerobic wastewater treatment device in which organic wastewater is treated by solid-liquid separation in a solid-liquid separation reaction tank, the solid-liquid separation reaction tank is partitioned by a wall into a precipitation area, a contact aeration area, and a biological filtration area. A contact material is placed inside each of the precipitation area, contact aeration area, and biological filtration area, and an aeration pipe is placed for blowing oxygen-containing gas such as air into the contact aeration area for aeration. A draft tube for introducing wastewater from the top to the bottom is disposed within the sedimentation area, and an outflow section is provided at the top of the settling area to drain the wastewater in the settling area to the contact aeration area, and the contact aeration area and the biological filtration area are connected to each other. A communication part is provided at the lower part of the wall that partitions the biological filtration area, and a circulation device is connected to the upper part of the biological filtration area to circulate the wastewater in the biological filtration area back to the sedimentation area. An aerobic wastewater treatment device characterized by being provided with an outflow section that allows part of the wastewater to flow out. (2) The aerobic wastewater treatment apparatus according to item 1, wherein an inclined plate is provided at the lower part of the draft tube and is inclined downwardly outside the draft tube. (3) In the aerobic wastewater treatment apparatus according to item 1, the aerobic wastewater treatment device is characterized in that the wall separating the settling region and the contact aeration region is provided with an overflow weir lower than the upper end of the wall. Device. (4) The aerobic wastewater treatment apparatus according to item 1, wherein an overflow weir lower than the upper end of the outer wall is provided on the outer wall of the biological filtration area. (5) In the aerobic wastewater treatment device described in paragraph 1, a container-shaped submerged weir is placed in the upper part of the biological filtration area to store wastewater while being buried in the wastewater, and the submerged weir is filled with wastewater. An aerobic wastewater treatment device characterized by being connected to a circulation device that circulates wastewater in a weir to a settling region. (6) In the aerobic wastewater treatment device according to item 1, the contact material in each region is filled in such a manner that the voids become smaller in the order of the sedimentation region, the contact aeration region, and the biological filtration region. Wastewater treatment equipment. (7) In the aerobic wastewater treatment device described in paragraph 1, backwashing air piping for backwashing is arranged below the contact material in each region, and the side walls are arranged inwardly at the bottom of each region. An aerobic wastewater treatment device comprising: a hopper section having an inclined shape with a reduced bottom area; and a sludge drawing mechanism provided at the bottom of the hopper section. (8) The aerobic wastewater treatment device according to item 1, characterized in that the contact aeration region and the biological filtration region are provided with a sludge return mechanism for returning the sludge accumulated at the bottom of each region to the settling region. Wastewater treatment equipment.