JP3424798B2 - Wastewater treatment method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel aeration and circulation type wastewater treatment method and apparatus.

[0002]

2. Description of the Related Art Conventionally, biological treatment methods such as an activated sludge method have been used in many wastewater treatment facilities. Biological treatment is divided into three stages: pretreatment, biooxidation treatment, and sludge treatment. Here, in the pretreatment stage, a device such as a screen, a sand basin, a sedimentation basin, or a floating tank is used. These devices remove coarse solids and inorganic suspended matter, etc., and reduce the organic load or the amount of organic substances to be processed in the device or facility that is continuously placed in the device and performs the biological oxidation treatment. I am busy.

In carrying out the biooxidation treatment, there are two forms of utilization of the microorganisms: a method in which the microorganisms are adhered and grown on the surface of a solid support, and a method in which a group of microorganisms is suspended in a liquid. The former is usually carried out using a fixed bed apparatus (catalytic oxidation treatment), and the latter is carried out using a fluidized bed apparatus (activated sludge treatment).

At the time of biooxidation treatment, organic substances in wastewater are assimilated by microorganisms and are mainly reduced at this stage (biooxidation treatment stage). On the other hand, a part of the microorganism that assimilates and proliferates organic matter forms flocs and precipitates to become sludge. Such sludge undergoes concentration and dehydration in the sludge treatment stage, which is carried out consecutively to the biological oxidation treatment. Here, if the amount of sludge to be treated is large, the operating costs of the concentration tank for concentrating the sludge, the dehydration tank for dehydrating the sludge, etc. will also increase.

Activated sludge treatment, which is one of the sludge treatment methods, is capable of treating substances that cannot be treated by other chemical treatments or physical treatments, and is capable of treating wastewater having a relatively high concentration. It also has advantages. However, it is vulnerable to changes in climate and changes in BOD (biochemical oxygen demand) load. That is, when the biota in the wastewater treatment tank collapses due to various causes such as a decrease in water temperature, the treatment capacity of the wastewater treatment tank is significantly reduced, and it takes several months to restore it. Further, in that state, if the wastewater having a high BOD load is allowed to flow into the wastewater treatment tank as it is, there is a high possibility that the biota in the tank will be destroyed, and therefore the wastewater cannot be directly introduced. Only after taking measures such as mixing with a liquid having a low BOD load, wastewater having a high BOD load cannot be supplied into the wastewater treatment tank. However, the dilution with a liquid having a low BOD load increases the amount of wastewater to be treated. As a result, operating costs increase and a large treatment facility is required.

In the case of the catalytic oxidation treatment, the restoration period is relatively short when the treatment capacity of the waste water treatment tank decreases. However, even in the case of contact oxidation treatment, it may take several weeks to several months for restoration. Further, there is a limit to the BOD load that can be treated even in the catalytic oxidation treatment, and the treatment capacity is not always satisfactory.

Under such circumstances, in the Kurume Medical Society magazine, Vol. 45, No. 8, published in August 1983, a container YC having a cross-sectional shape shown in FIG. A container sold under the trade name "Yakult" by people: hereinafter referred to as "Yakult container" in the present specification) is a separable tank that uses a relatively small plastic container with the bottom removed as a filter medium. It is disclosed. It has been shown that the quality of water after treatment can be improved by using this septic tank. Also, the actual fair 2
No. 5917 discloses a septic tank using a similar small plastic container as a filter medium, and describes effects such as a reduction in the number of cleanings of the septic tank and an early restoration.

These septic tanks are suitable for treating wastewater having a low BOD load. However, when the wastewater having a high BOD load flows in, microorganisms propagate between the small plastic containers as the filter medium, which causes a problem that the region filled with the filter medium is blocked. That is, when such a blockage occurs, the wastewater to be treated is not supplied to the blocked region, so that the circulation of the treated water does not occur, resulting in a so-called “stuck state”. Further, as a matter of course, since the air for aeration is not supplied to the closed area, the circulation by the air does not occur and the aeration process by the contact between the air and the drainage is not performed. Therefore, the processing efficiency in the tank is significantly reduced. That is, the conventional technology was unsuitable for treating wastewater having a high BOD load. Further, although the number of days required for restoration and the amount of sludge to be generated are also reduced as compared with the case of the usual activated sludge treatment, it cannot be said to be sufficiently small.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been proposed in view of the above-mentioned prior art, and in performing aeration circulation treatment of wastewater discharged from factories and the like, seasonal variation and change of BOD load of introduced wastewater. It is an object of the present invention to provide a wastewater treatment method and device in which biota are less likely to be destroyed even when such a situation occurs, and when the destruction occurs, restoration is quick.

Another object of the present invention is to provide a wastewater treatment method and apparatus that can reduce the amount of sludge generated without causing blockage even if the BOD load of the introduced wastewater is high.

[0011]

In the wastewater treatment method of the present invention, the wastewater is introduced into an aeration tank filled with a filter medium, and the microorganisms fixed on the filter medium are brought into contact with the wastewater introduced into the aeration tank. Biological treatment is performed on the wastewater,
Air is supplied into the aeration tank through the center well and the first air pipe, which penetrates the perforated plate laid on the upper surface of the pedestal standing under the aeration tank and has the upper end protruding above the water surface of the aeration tank. Air is supplied into the aeration tank through a perforated plate at the bottom of the aeration tank and a second air pipe, and at least two or more of the aeration tanks are continuously arranged, and the partition wall separates adjacent aeration tanks. The drainage is introduced into the aeration tank of the next stage through the formed drainage passage hole, and as a result, the circulation treatment of the drainage is performed continuously in at least two aeration tanks.

According to the present invention having such a constitution, the BOD load of each aeration tank can be reduced to maintain the microbial balance inside the aeration tank appropriately, and the aeration tank in which the microbial balance is broken can be promptly released. It can be revived.

Here, the circulation treatment of wastewater according to the present invention is
It is particularly preferable that the aeration is performed continuously in three or more aeration tanks. Although the aeration tank used in the present invention can efficiently treat waste water even if only one tank is used, it is convenient to use three or more aeration tanks because recovery at the time of occurrence of bulking is prompt. In addition, it is possible to appropriately combine the circulation modes in the aeration tank to obtain the effect of preventing clogging of the filter medium and other effects.

In carrying out the wastewater treatment method of the present invention,
With the air supplied through the first and second air pipes, in the aeration tank on the most upstream side of the aeration tank in which two or more tanks are continuously arranged, the treated water in the aeration tank (in the aeration tank , Biological treatment, physical treatment, or chemical treatment) circulates so as to rise from the bottom to the top, and the treated water falls from the top to the bottom in the aeration tank on the most downstream side. It is preferable to configure so as to circulate.

In the treatment apparatus of the present invention in which a plurality of aeration tanks are connected, the first aeration tank (or the first tank) is supplied with the waste water to be treated as it is. Gaps and porous plates are easily clogged (blocked).
In addition, the first aeration tank (first tank) has an extremely high BOD load, and is an environment in which microorganisms that assimilate organic substances easily proliferate in large quantities. Therefore, the amount of flock formed increases,
The layer of microorganisms also becomes thicker. These matters also cause a gap in the filter medium of the aeration tank and a blockage in the perforated plate. Therefore, in the aeration tank on the most upstream side of the aeration tank (first aeration tank), it is preferable to circulate the treated water in the aeration tank so as to rise upward. In other words, the circulation in the aeration tank (such as the rise of treated water) generated by the supply of air has a very strong effect of dispersing sludge, so that it can be attached to or generated on the filter medium by adjusting the air supply amount. It is possible to control the amount of sludge to be discharged.

However, even in the aeration tanks of the second and subsequent stages,
Depending on the BOD load or the amount of sludge produced, the treated water may be circulated so as to rise upward. That is, even if the BOD load is too high and the balance of microorganisms in the first aeration tank may be disturbed, the treated water is raised and circulated, so that the downstream aeration tank receives the treatment of organic substances. This is because it becomes possible to reduce the BOD load of the first aeration tank. In other words, in the aeration tank on the most upstream side of the aeration tank (first aeration tank), the treated water in the aeration tank is circulated so as to rise upward (upper circulation processing), so that the BOD of the first aeration tank is increased. Reduce the load,
The balance between the internal microorganisms and the BOD load is maintained more favorably. When the microbial balance of the first aeration tank is disrupted, the microbes on the surface of the microflora adhering to the filter medium (the surface on the side in contact with the wastewater) die, but the microbes inside the microflora As it propagates further, it allows the rapid recovery of the biota in the tank.

On the other hand, in the final tank (the most downstream aeration tank) of the aeration tanks that are continuously arranged, the wastewater is biologically and chemically treated in the upstream aeration tank. , The BOD load is extremely small. The treatment that allows the treated water to circulate downward (downward circulation treatment) is
In this way, the BOD load is relatively small. This downward circulation process forms a gentle flow path in the tank, facilitates contact between the BOD load and the biota, and
The effect that the components are finally removed is improved. Further, in the aeration tank where the downward circulation process is performed, when the BOD load is high, sludge is accumulated on the upper part of the filter medium. Therefore, the confirmation and judgment of the sludge removal timing of the sewage treatment device can be easily and accurately performed. For the above reasons, the treated water is circulated in the most downstream aeration tank so as to descend downward.
However, even if it is an aeration tank on the upstream side of the final tank, BOD
Depending on the load or the installation position of the sludge discharge mechanism, the treated water may be circulated so as to descend.

Here, in the present invention, it is preferable that a plurality of flow paths having different flow velocities are formed on the surface of the filter medium. Further, it is preferable that the filter medium is a plastic food container (for example, “Yakult container”). If you use a plastic food container such as a Yakult container as the filter medium, as is clear from the above-mentioned Kurume Medical Society magazine Vol. 45, No. 8 issued in August 1983, and Jpn. This is because the treatment efficiency of the wastewater treatment facility will be improved and the microbial flora will be restored promptly when the balance is lost. That is, when a Yakult container-like filter medium is used, a thick biological layer is formed in the depressions and the like, so that the revival becomes faster.

Further, in the present invention, it is preferable that the filter medium has a hierarchical structure in which at least two layers are laminated in the aeration tank. Here, when constructing the hierarchical structure of the filter medium, it is preferable to store a plurality of filter mediums in a net and stack the nets in which the filter mediums are stored. By putting the filter medium in the net, it is possible to prevent the filter medium from moving due to aeration or the like generated by the supply of air. More specifically, if the filter medium moves, the microflora attached to the filter medium may be destroyed, which may seriously affect the wastewater treatment capacity. On the other hand, if the filter medium is put in a net so that it does not move, the microflora is stably maintained.
Here, the reason for forming a hierarchical structure in which a plurality of tanks are laminated is to increase the surface area of the filter medium and to stabilize the filter medium. That is, depending on the shape and material of the filter medium, there are some that have poor stability in the treatment tank. Therefore, by storing and holding a fixed amount in a net or the like, stabilization can be performed easily and inexpensively. As a result, the contact time between the microorganisms adhering to the surface of the filter medium and the treated water becomes longer, and the recovery in the case where the microflora deteriorates becomes faster. Also, in this case, if the filter medium is too thick, the possibility of blockage increases,
It is necessary to design in consideration of this point.

The waste water treatment apparatus of the present invention comprises an aeration tank, a stand for standing and supporting the lower part of the aeration tank, a perforated plate laid on the upper surface of the stand, and a lower end penetrating the perforated plate. A center well whose upper end projects above the water surface of the aeration tank,
A filter medium filled inside the aeration tank, and at least two or more aeration tanks are continuously arranged. The aeration tank is equipped with a drainage introduction pipe for introducing drainage, and an adjacent aeration tank is provided. Drainage passage holes are formed in the partition walls to allow the wastewater being processed to flow into the aeration tank at the next stage. It is characterized by including a first air pipe for supplying and a second air pipe for supplying air into the aeration tank through a perforated plate at the bottom of the aeration tank.

In carrying out the present invention, the aeration tank has three
It is particularly preferable that the tank or more is continuously arranged.

Here, in the first and second pipes, in the aeration tank on the most upstream side of the aeration tanks that are continuously arranged, the treated water in the aeration tank rises from the bottom to the top and circulates, In the aeration tank on the most downstream side, it is preferable that the treated water is arranged so as to descend and circulate from the upper side to the lower side.

The filter medium is preferably shaped so as to form a plurality of flow paths having different flow velocities on the surface thereof. Alternatively, the filter medium is preferably a plastic food container such as a "Yakult container".

Further, in the wastewater treatment equipment of the present invention,
It is preferable that the filter medium has a hierarchical structure in which at least two layers are laminated in the aeration tank.

Also in the wastewater treatment equipment of the present invention, the same operational effects as the above-mentioned wastewater treatment method of the present invention can be obtained.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. First, a wastewater treatment facility to which the embodiment of the present invention is applied will be described with reference to FIG. Wastewater to be treated is introduced through a drainage pit 10 into a wastewater treatment facility (FIG. 1) generally designated by EM. And the wastewater to be treated is the drainage line L1.
Is stored in the storage tank 12 via the. This storage tank 12 is
It is a facility that functions as a settling tank and has the function of executing pretreatment.

In the facility EM shown in FIG. 1, a plurality of aeration tanks filled with a filter medium (in FIG. 1, the aeration tanks are generally indicated by the reference symbol C) are continuous, and in the embodiment of FIG. (4 series) are arranged in parallel. Storage tank 1
The water to be treated, which is stored in No. 2 (preliminary treatment has already been performed at this stage), is supplied to a continuous aeration tank of any series via a drain line L2 that branches into four. . The continuous aeration tank will be described later with reference to FIG.

In the embodiment of FIG. 1, seven aeration tanks C1.
..C7s form one series in succession. In the aeration tank C, the arrow indicated by the dotted line indicates the flow of treated water. The drainage line L2 communicates with the most upstream aeration tank C1 ... While circulating inside each aeration tank, biochemical by microorganisms attached to the surface of the filter medium filled in the aeration tank. While undergoing the treatment, it sequentially flows through the aeration tanks C2-C7 on the downstream side.

The wastewater that has undergone biochemical treatment in the continuous aeration tanks C1-C7 is the most downstream aeration tank C7.
.. from the processing tank C-PR (two are installed in FIG. 1). This treatment tank C-PR is provided for demonstrating the treatment capacity of the wastewater treatment apparatus according to the embodiment (PR tank), and is configured in an open state, and gold fish, grass fish, and other Freshwater fish are bred. The PR tank C-PR itself has a wastewater treatment capacity, but in the illustrated embodiment, it is currently used as a member for demonstration. However, if the load increases in the future, the PR tank C-PR can handle the increased load.

As will be described later, in the illustrated embodiment, the water flowing out from the aeration tank C7 has undergone sufficient biochemical treatment, and is therefore purified to the extent that freshwater fish can be raised. In order to appeal this to the visitors who saw the facility EM of FIG. 1, the treatment tank C-PR is configured in an open state, and the water from the aeration tank C7 is introduced into the PR tank C-PR. Then, the observer can visually recognize that the fresh water fish can be bred with the water from the aeration tank C7.

The water (treated water) discharged from the PR tank C-PR is introduced into the second settling tank 14 via the drain lines L3 and L4 which join together on the way. Then, the treated water is discharged to the river through the drain line L5. here,
According to the illustrated embodiment, since the amount of suspended solids (SS) generated is extremely small, the second precipitation tank 14 can be omitted.

Here, as described above, the treated water is the aeration tank C.
It should be added that since the freshwater fish are purified to the extent that they can be raised when they are discharged from 7, there is no fear of environmental damage even if the discharge water of the second settling tank 14 is discharged into a river. .

In FIG. 1, reference numeral 16 is a blower chamber provided with a blower for supplying air to the aeration tank C through an air pipe (not shown). The flow of air in the aeration tank C will be described with reference to FIG. Reference numeral 18 is a dehydrator room, reference numeral 20 is a concentrating tank, and reference numeral 22 is a cake hopper for storing dehydrated sludge (cake). In the prior art, the concentration tank needed to have a capacity of 100 m ³ . On the other hand, according to the illustrated embodiment, the amount of sludge generated is extremely small, so that a small-capacity concentrating tank is sufficient, or the concentrating tank itself becomes unnecessary.

Next, mainly referring to FIG. Figure 2
1 shows a detailed structure of a series of aeration tanks arranged in series. The wastewater treatment apparatus according to the embodiment of FIG. 2 includes aeration tanks C1-C7, and pedestals B1-B7 that stand on the lower side of the aeration tanks C1-C7 and support the respective aeration tanks.
The gantry B1-B7 has a perforated plate P laid on the upper surface and a center well W. The center well W has a lower end penetrating the perforated plate P and an upper end thereof in an aeration tank C1-. It projects above the water surface of C7. And aeration tank C
The inside of 1-C7 is filled with a filter medium (Yakult container) as indicated by symbol YC in FIG. As described above, in the embodiment shown in FIGS. 1 and 2, the seven aeration tanks C1 are provided.
-C7 (at least two aeration tanks) are continuously arranged.

Then, the storage tank 12 (the storage tank 1 shown in FIG.
2) to a most upstream aeration tank (the leftmost aeration tank in FIG. 2) C1 by a pump 26, a drain line L2 (a drainage introducing pipe for introducing drainage into the aeration tank: FIG. 1).
(Corresponding to the drainage line L2 of the above), the wastewater to be treated is supplied. In addition, a partition 28 that separates adjacent aeration tanks.
A drainage passage hole 30 (in FIG. 2, only the position thereof is indicated by reference numeral “30”) for allowing the wastewater being treated to flow into the aeration tank of the next stage is formed in the. In addition,
In FIG. 2, the drainage passage hole 30 is shown above the water surface of each tank C1-C7 for the sake of clarity, but actually, it is formed below the water surface of the aeration tank C1-C7. Further, reference numeral 32 in FIG. 2 denotes a water sprinkling plate provided in the center well W.

A predetermined number of the filter media YC (case-by-case)
Packed in the number specified in the case)
(In FIG. 2, only the aeration tank C1 is marked with a reference numeral), and it is arranged in the aeration tanks C1 to C7. At this time, in order to stabilize the filter medium, it is preferable to form a hierarchical structure in which at least two layers are laminated.

The series of a plurality of continuous aeration tanks C1-C7 includes a first air pipe 40 and a second air pipe 4.
2 (only part of which is shown in FIG. 2). The first air pipe 40 is connected to the aeration tank C1-C via the center well W of the aeration tank C1-C7.
Air is supplied to the inside of each of the aeration tanks 7, and the second air pipe 42 is laid on the perforated plate P at the bottom of the aeration tank, and the aeration tank C is provided.
Air is supplied to the inside of each of 1-C7.

Here, due to the action of the air supplied from the second air pipe 42 on the perforated plate P, in the aeration tank C1 on the most upstream side (the leftmost side in FIG. 2), the aeration tank C is provided.
Internal water (treated water) circulates in such a manner that the treated water in 1 rises upward. On the other hand, due to the action of the air supplied from the center well W via the first air pipe 40, in the aeration tank C7 on the most downstream side (the most right side in FIG. 2), the treated water falls downward therein. The treated water circulates.

Explaining in more detail, aeration tanks C2 and C3
2, the air supplied from the center well W through the first air pipe 40 carries the treated water, and as shown by the solid line arrow in FIG.
The treated water is circulated from below to above in such a manner as to raise the treated water. On the other hand, in the aeration tanks C4-C7,
The air supplied from the first air pipe 40 and the center well W carries the treated water and rises in the center well W as indicated by the dotted line indicated by the arrow in FIG. Then, as shown by the solid line arrow in FIG. 2, the sprinkler plate 32 circulates the treated water from above to below the stacked packs of filter media YC ...

In the aeration tanks C2-C6 of the second and subsequent stages, whether the treated water rises or falls in the hierarchical structure of the filter medium pack YC ...
It can be determined on a case-by-case basis according to other conditions such as the BOD load or the amount of sludge generated.

The treated water discharged from the aeration tank C7 on the most downstream side is passed through the drainage passage hole 30 to the PR tank C-PR (see FIG. 1).
Same with). And drainage lines L3, L4
Is discharged to the discharge side via.

In the illustrated embodiment, an air nozzle (not shown) is provided below the filter medium YC or YP, and air is supplied from the air nozzle to cause convection from the lower portion to the upper portion of the filter medium (aeration tank C1 in FIG. 2). -See the arrow indicated by the solid line inside C3) to form the center well W
It is possible to supply air from an air nozzle (not shown) installed inside to generate convection inside the aeration tank C4-C7 shown in FIG.

The air nozzle (not shown) used here is one that has been conventionally used for cleaning the inside of the aeration tank for the aeration process. This prevents the gap between the filter media YC (see FIG. 3) or YP (see FIG. 2) in the first tank C1 having the highest BOD load from being blocked. That is, by increasing the flow velocity of convection (water flow) between the filter media, the microorganisms are prevented from sticking to the filter media. On the other hand, in the final tank C7, by performing convection from the upper part to the lower part of the filter medium, the chance of contact between the filter medium YP (see FIG. 3) and the solid content in the wastewater is increased and the flow velocity of the convection is slowed down. , The solid content is easily separated. Thus, in order to combine the aeration circulation from the upper part to the lower part and the aeration circulation from the lower part to the upper part, the aeration tank has two
Although it is only necessary to have a tank, it is preferable to have three or more aeration tanks because the aeration method of the second and subsequent tanks (intermediate tank) may be appropriately adjusted depending on the load of raw water flowing in and the state of the first tank. .

The filter media used in the aeration tanks C1-C7 are synthetic resin materials such as polystyrene and polyvinyl chloride,
Although stone, cement and the like can be preferably used, a plastic filter medium that is easy to process is preferable for reasons such as adhesion of microorganisms, effective securing of surface area and reduction of clogging possibility. As the shape of the filter medium, a regular aligned synthetic filter medium such as honeycomb or flat may be used, but since microorganisms adhere to the surface of the filter medium and the pore structure, it is as irregular as possible and has many irregularities and bends. Is good. In particular, as described above, FIG.
The shape of the Yakult container indicated by is preferable.

If the shape of the filter medium is irregular, the strength of the water flow and the direction of the flow change depending on the position of the surface of the filter medium, so that the growth conditions of the microorganisms also become diverse, and as a result, many kinds of microorganisms propagate. Becomes Therefore, it is possible to assimilate many kinds of substances contained in the wastewater. Further, especially in the recessed portion, it is difficult for the convection to inhibit the colonization of the microorganisms, and thick microorganisms are formed, so that the anaerobic bacteria propagate. For this reason, a large amount of anaerobic bacteria will be distributed throughout the whole, so that the amount of sludge and the amount of nitrogen in the wastewater are reduced.

In designing the aeration tank, it is necessary to consider the BOD load of the wastewater flowing into the entire aeration tank and the first tank C1. If the BOD load is high, the volume of the aeration tank may be increased or the number of tanks may be increased. However, it will be costly to expand the equipment, so it is necessary to pay attention to the processing efficiency and to design appropriately. For example, if the height of the gantry is too low, the effect of suppressing the rolling up of the sediment in the tank will be weakened, and if it is too high, the cost will increase. For this reason, when treating normal factory wastewater,
A height of 0.5 to 1.5 m, particularly about 1 m is preferable. In consideration of the circulation efficiency of treated wastewater, the width from the filter medium to the water surface is preferably 0.2 to 1 m, particularly about 0.5 m.

Here, when the Yakult container (synthetic resin material) of FIG. 3 is used as the filter medium, the width of the filter medium is 1 to 1.
If it is about 3.0 m, good treatment efficiency can be maintained and blockage can be prevented, and 1.5 to 2.5 m is particularly desirable.

In addition to this, it is possible to reduce the cost required for the equipment by making various measures. For example, by providing a threshold 80 in FIG. 2 in the aeration tanks C1 to C7, it is possible to obtain substantially the same result as when the number of aeration tanks is increased. Alternatively, if the aeration method (convection direction, etc.) of the intermediate tank C2-C6 is adjusted, the BOD of the drainage flowing in through the drainage line L2
The most efficient processing becomes possible according to the load. That is, by using the convection directions (aeration method) of the intermediate tanks C2-C6 from top to bottom, bottom to top, or a combination of the two, it is possible to cope with fluctuations in the BOD load of wastewater.

According to the present invention, it can be applied to domestic drainage.

[0050]

Example 1 An example of the present invention will be described below. Here, the application of the embodiment is a wastewater treatment facility, domestic sewage treatment, a chemical factory, and the like.

BOD volume load is 0.25k to the whole
g / cubic meter / day, 0.75 kg / for the first tank
Cubic meter / day, while the dimension is 2.5m ×
5m x 4m first tank C1 and 2.5m x 2.5m x 4m
6 aeration tanks C2-C7 were provided. Also, the size is 2.
One PR tank of 5 m x 5 m x 4 m was installed. And P
Grass fish were bred in the R tank.

FIG. 4 shows the load amount, treated water amount, BOD, COD, suspended matter (SS), total nitrogen (TN: mg / l), sludge generation rate (%), transparency, etc. in such an embodiment. Is shown. No sludge was generated in this example.

[0053]

[Embodiment 2] In the embodiment shown in FIG. 5, the sewage treatment facility EM to which the present invention is applied and the activated sludge treatment facility EM-P according to the prior art are arranged independently of each other and arranged in parallel. It is provided in the form. In FIG. 5, the facility EM using the filter medium (filter medium with the bottom of the Yakult container removed) as shown in FIG. 3 is the first tank C to which the raw water of the wastewater to be treated is supplied.
B11 and the following continuous aeration tanks CB12-CB21 are provided. And each aeration tank CB11-CB21
Is filled with the filter medium shown in FIG. The raw water flows through the continuous aeration tanks CB11-CB21 as shown by the arrow in FIG. 5, and reaches the precipitation tank 114. Then, it is discharged to a river or the like not shown.

The size of the aeration tank CB11 is 2.5 mx
The size of the aeration tanks CB12-CB21 is 2.5 m × 2.5 m × 4 m, and the size of the precipitation tank 114 is 2.5 m × 10 m × 4 m.

On the other hand, in the conventional treatment facility EM-P, the raw water supplied is the first water tank CB1-P and the second water tank CB2-.
P, the third water tank CB3-P, the fourth water tank CB4-P, the first precipitation tank 112, the second precipitation tank 114-P, and the like are discharged to a river or the like. ◎ Here, the size of each of the first water tank CB1-P to the fourth water tank CB4-P is 2.5 m × 10 m × 4 m. Also,
The dimensions of the first settling tank 112 are 5 m × 5 m × 4 m. Further, the second settling tank 114-P has a cylindrical shape, and its dimensions are 7.5 m in diameter and 3.6 m in height.

The results of comparison between the water treated by the treatment facility EM according to the embodiment of the present invention and the water treated by the conventional treatment facility EM-P are shown in FIGS. 6-11. As is clear from FIG. 6, the generation of sludge in this example is far less than in the conventional case. In addition, the first embodiment described above
Then, the generation of sludge was zero. In addition, in FIG.
Although the amounts of D, COD, and suspended solids (SS) are sufficiently reduced, the present invention is more effective in the case where the BOD load of drainage is higher. Furthermore, as is clear from FIG. 8, the ability to reduce the nitrogen content also
Example 2 is improved over the conventional facility EM-P. Here, FIG. 9 shows constituent components of raw water and discharged water (water that is treated and discharged). And FIG. 10 shows each numerical value shown in FIG. 9 by the processing amount per day.
Here, in FIG. 10, the discharged water is shown by the display “discharged”. In addition, the filter media used in the processing facility EM,
That is, the filter medium as shown in FIG. 3 (the filter medium obtained by removing the bottom of the Yakult container) is shown as “Y filter medium” in FIGS. 9 and 10. FIG. 11 is a processing facility EM according to an embodiment of the present invention.
The running costs of the processing facility EM-P according to the related art (shown simply as “Y filter medium” in FIG. 11) are shown in comparison. FIG. 11 shows the cost required for treating 1 cubic meter of raw water, showing that the embodiment of the present invention (denoted as “Y filter material”) also exceeds the conventional technology in terms of running cost. There is.

[0057]

EFFECTS OF THE INVENTION According to the present invention described above, wastewater to be treated can be favorably biochemically treated with anaerobic and aerobic bacteria. Even if it is released, it will not adversely affect the environment. Therefore, it greatly contributes to pollution control.

Further, even if the microbial balance in the aeration tank is lost, its recovery is extremely fast, so the treatment capacity of the wastewater treatment facility to which the present invention is applied is immediately restored. In addition to this, it is not necessary to adjust the flow rate and the operating cost is reduced.

In the conventional wastewater treatment, since aerobic bacteria are the main treatment, a large amount of flocs are generated and a precipitation tank and a concentration tank are required. However, according to the present invention, treatment with both aerobic and anaerobic bacteria is performed. Here, the anaerobic bacterium mainly exerts the function of generating gas rather than generating floc. Therefore, the number of anaerobic bacterial cells themselves does not grow so much. Therefore, the amount of flocs generated is reduced, and the settling tank and the concentration tank are unnecessary. Since the amount of flock generated is small, there is an effect of preventing blockage.

[0060]

As described above, according to the present invention in which the action of the aerobic bacterium and the action of the anaerobic bacterium are used in combination, the microbial balance is rapidly restored, and the floc and the nitrogen content are reduced at the same time. is there.

[Brief description of drawings]

FIG. 1 is a plan view of a wastewater treatment facility to which the present invention is applied.

FIG. 2 is a sectional front view showing the present invention.

FIG. 3 is a cross-sectional view showing a filter medium preferably used in the present invention.

FIG. 4 is a table showing the operational effects of the first embodiment of the present invention.

FIG. 5 is a plan view showing the structure of the wastewater treatment facility according to the second embodiment of the present invention.

FIG. 6 is a table showing the operational effects of the second embodiment.

FIG. 7 is a table showing other operational effects of the second embodiment.

FIG. 8 is a table showing still another operation and effect of the second embodiment.

FIG. 9 is a table showing the composition of raw water used in the second example and treated water.

FIG. 10 is a table showing the composition shown in FIG. 9 as numerical values per day.

FIG. 11 is a table showing yet another operation effect of the second embodiment.

[Explanation of symbols]

EM ・ ・ ・ Wastewater treatment facility 10 ... Drainage pit L1-L5 ... Drainage line 12 ... Storage tank C, C1-C7 ... Aeration tank C-PR ... PR tank (processing tank) 16: Blower room 18 ... dehydrator room 20: Concentration tank B1-B7 ... Stand W: Center well 26 ... Pump 28 ... Partition 30 ... Drainage passage hole 32 ... A sprinkler plate. YC ... filter material YP: Pack of filter media

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoto Ishida 1-1-19 Higashishimbashi, Minato-ku, Tokyo Yakult Honsha Co., Ltd. (72) Inventor Hoshino Yoshino 1-chome, Higashishimbashi, Minato-ku, Tokyo No. 1-19 Yakult Honsha Co., Ltd. (72) Inventor Takao Noda 1-1-19 Higashishimbashi, Minato-ku, Tokyo Yakult Honsha Co., Ltd. (72) Inventor Toshiyuki Imamura Higashishimbashi, Minato-ku, Tokyo 1-1-119 Yakult Honsha Co., Ltd. (72) Inventor Hiroaki Suenaga 1-1-19 Higashishimbashi, Minato-ku, Tokyo Yakult Honsha Co., Ltd. (56) Reference Japanese Patent Laid-Open No. 2-115097 (JP , A) JP 4-156997 (JP, A) JP 7-232186 (JP, A) JP 9-66290 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) C02F 3/06 C02F 3/10

Claims (8)

(57) [Claims] 1. A biological treatment is performed on the wastewater by introducing the wastewater into an aeration tank filled with a filter medium and contacting the microorganisms fixed on the filter medium with the wastewater introduced into the aeration tank. The air is introduced into the aeration tank through the center well and the first air pipe, which penetrates the perforated plate laid on the upper surface of the pedestal standing below the aeration tank and has the upper end protruding above the water surface of the aeration tank. Air is supplied into the aeration tank through the porous plate at the bottom of the aeration tank and the second air pipe, and at least two or more aeration tanks are continuously arranged to separate adjacent aeration tanks. Wastewater treatment is characterized in that the wastewater is introduced into the aeration tank of the next stage through the drainage passage hole formed in the partition wall, and as a result, the circulation treatment of the wastewater is continuously performed in at least two aeration tanks. Method. 2. The aeration tank on the most upstream side of the aeration tank in which two or more tanks are continuously arranged is treated by the air supplied through the first and second air pipes. The wastewater treatment method according to claim 1, wherein the water is circulated so as to rise from the lower side to the upper side, and the treated water is circulated so as to fall from the upper side to the lower side in the aeration tank on the most downstream side. 3. The wastewater treatment method according to claim 1, wherein a plurality of flow paths having different flow rates are formed on the surface of the filter medium. 4. The wastewater treatment method according to claim 1, wherein the filter medium is a plastic food container. 5. An aeration tank, a pedestal for standing and supporting below the aeration tank, a perforated plate laid on the top surface of the gantry, a lower end penetrating the perforated plate and an upper end of the water surface of the aeration tank. It has a center well protruding upward and a filter medium filled inside the aeration tank, and at least two aeration tanks are continuously arranged, and the wastewater is introduced into the aeration tank. Equipped with pipes, a partition wall that separates adjacent aeration tanks has a drainage passage hole that allows the wastewater being processed to flow into the next stage aeration tank. A first air pipe for supplying air to the inside of the aeration tank via the air passage, and a second air pipe for supplying air to the inside of the aeration tank via a perforated plate at the bottom of the aeration tank. Wastewater treatment equipment. 6. The first and second pipes circulate in the aeration tank on the most upstream side of the aeration tanks that are continuously arranged so that the treated water in the aeration tank rises from below to above, The wastewater treatment equipment according to claim 5, wherein the treated water is disposed so as to circulate downward from the uppermost aeration tank. 7. The waste water treatment apparatus according to claim 5, wherein the filter medium has a shape such that a plurality of flow paths having different flow rates are formed on the surface thereof. 8. The wastewater treatment device according to claim 5, wherein the filter medium is a plastic food container.