JPH08103778A - Apparatus and method for purifying sewage containing water bloom - Google Patents

Abstract

PURPOSE: To economically treat the sewage by automatically and continuously separating water bloom while delaying the re-generation of water bloom. CONSTITUTION: A sewage purifying apparatus is equipped with a first tank body 4 receiving water to be treated containing water bloom from lakes and marshes 1, a first gas-liquid mixing device 5 having an air pipe having air jet orifices provided to the underside part thereof and blades provided along the air pipe and rotated in the first tank body to eject ozone from air jet orifices, a second tank body 20 partitioned into a water bloom decomposing and separating region A1 and a first fresh water region A2 to receive fresh water, a stirring means 22, an ozone decomposing region B1, a second fresh water region B2 and a return pipe 26 returning fresh water in the second fresh water region to lakes and marshes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for purifying sewage containing water-bloom and the like for continuously separating water-bloom and the like generated in eutrophied ponds and lakes.

[0002]

2. Description of the Related Art In recent years, in lakes and marshes in various places, a so-called water-bloom phenomenon has become a problem in which eutrophication of water quality causes abnormal growth of single-celled algae, phytoplankton, etc., and makes the water surface muddy green.

[0003] In order to remove water-bloom and the like from such contaminated lake water and the like, conventionally, lake water and the like are pumped up and a flocculant is added, and then sand and filtration filters are used to contain the water-bloom and the like. Etc., the pH of fresh water from which water-bloom and the like have been removed is adjusted, and then returned to lakes and marshes (hereinafter, this method is referred to as the "first conventional method").

As another method, the wastewater is pumped up and a coagulant is added to the wastewater to increase the size of water-blooms in the wastewater, and then fine air bubbles are raised in the wastewater under pressure. In addition, a method is also used in which the water-bloom and the like are floated and separated by the bubbles (hereinafter, this method is referred to as a "second conventional method").

As another method, it is also practiced to pump up sewage and highly compress it to float the water-bloom and the like with air (hereinafter, this method is referred to as the "third conventional method"). ).

Furthermore, the wastewater is pumped up and ozone is finely dissolved and dissolved therein, and the ozone-dissolved wastewater is pressurized to promote the decomposition of water-bloom etc. by ozone, and the wastewater is guided to the lower part of the tank under normal pressure. A method has also been proposed in which blue-green algae and the like are floated and separated by rising micronized bubbles (see Japanese Patent Application Laid-Open No. 4-335460 filed by the applicant of the present application. Hereinafter, this method is referred to as "fourth conventional method"). .

[0007]

However, in the above-mentioned first conventional method, the filtering sand and the filtering filter are immediately clogged, and a certain amount of separation is carried out by batch processing, so that the processing efficiency is poor. .

In the first and second conventional methods, since the coagulant is used, if too much coagulant is added, there is a risk of increasing the load on water, and in continuous use,
Since it is necessary to appropriately change the amount of the coagulant added while observing the load change of the coagulant due to the coagulant, there is a drawback that the wastewater purification work is complicated.

In the above-mentioned first to third conventional methods, since the blue water and the like are only physically removed from the sewage, plankton and the like still survive in the fresh water returned to the lakes and marshes after the filtration treatment. These residual plankton etc. started to grow again, and there was a problem that the water-bloom regenerated in a short period of time.

In the above-mentioned first to third conventional methods, a specialized management engineer is required, and it has been difficult to perform unmanned continuous operation for a long period of time.

Since the second to fourth conventional methods include the process of pressurizing the sewage, there is a problem that the amount of energy consumption is large and the economy is low.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to continuously separate the water-bloom etc. unattended and delay the re-generation of the water-bloom etc.
It is intended to provide an economical sewage treatment apparatus and sewage treatment method.

[0013]

In order to solve the above problems, a sewage purification apparatus according to the present invention comprises a pump for sucking treated water containing water-bloom and the like from lakes and marshes, and a lower portion of the treated water from the pump. Side has a first tank body, a plurality of gas ejection holes at the lower side of the ventilation pipe whose lower end is closed, and blades along the ventilation pipe, and is rotated in the first tank body. A first gas-liquid mixing device for ejecting ozone from the gas ejection hole and the first tank body;
The first gas-liquid mixing device and the first separation member that separates the Aoko decomposition and separation area where it exists and the first fresh water area other than that, and makes them communicate with each other at their lower parts, There is a second tank body that receives the fresh water in the first fresh water area on the lower side thereof, a stirring means provided in the second tank body, and the stirring means in the second tank body. A second partition member that divides the ozone decomposing area and the second fresh water area other than that into the two areas, and connects the two areas below each other with each other, and the fresh water in the second fresh water area to a lake or the like. It is characterized by comprising a return pipe for returning.

Further, the method for purifying sewage according to the present invention sequentially carries out a process for decomposing and separating water-bloom etc., a process for decomposing ozone, and a process for bioprocessing.

In the process of decomposing and separating the water-bloom and the like, the first tank body for receiving the treated water containing the water-bloom and the like at the lower side thereof, and a plurality of gas ejection holes at the lower side of the ventilation pipe having the closed lower end, Having a blade along the ventilation pipe, a first gas-liquid mixing device that is rotated in the first tank body to eject ozone from the gas ejection hole, and the first tank body,
The first gas-liquid mixing device and the first separation member that separates the Aoko decomposition and separation area where it exists and the first fresh water area other than that, and makes them communicate with each other at their lower parts, Is a process of decomposing and separating water-bloom and the like contained in the treated water in a water-blowing and water-decomposing and separating tank comprising

In the ozone decomposing process, a second tank body for receiving the fresh water in the first fresh water area at its lower side, a stirring means provided in the second tank body, and the second tank. The inside of the body is divided into an ozone decomposing area in which the agitating means is present and a second fresh water area other than that, and a second partitioning member that allows the lower parts of both areas to communicate with each other is provided. This is the process of decomposing ozone in the ozone decomposing tank.

The biotreatment process is a process in which bacteria are brought into contact with the liquid in the second fresh water zone.

In the purification device or the purification method, a standing plate is provided around the blades of the first gas-liquid mixing device, and the first gas-liquid mixing device and the standing plate are present in the water-bloom, etc. It is preferable to dispose the first partition member so as to partition the first tank body into the decomposition / separation area and the other first fresh water area.

In the purifying apparatus or the purifying method, the stirring means has a plurality of gas ejection holes and a blade extending along the ventilation pipe at a lower side portion of the ventilation pipe having a closed lower end. It is preferable to use a second gas-liquid mixing device that is rotated in the air and ejects air from the gas ejection hole.

Further, in the purifying device or the purifying method, the second gas-liquid mixing device may be configured to selectively eject ozone and air from the gas-liquid ejection hole.

Furthermore, in the purification apparatus, it is more preferable to provide a biotreatment tank for bringing bacteria into contact with fresh water returned to a lake or the like in the middle of the return pipe.

[0022]

According to the present invention, first, treated water containing water-bloom and the like is sucked up from lakes and marshes by the pump. The treated water that has been sucked up is supplied from the lower side of the first tank body to the inside of the tank body for decomposing and separating water-bloom and the like.

The first gas-liquid mixing device in the tank body is rotated in the decomposition / separation zone for water-bloom and the like to eject ozone from the gas ejection holes into the treated water. That is, when the ventilation pipe rotates, a vortex flow is generated in the treated water and a negative pressure is generated in the treated water on the back side of the blade in the rotation direction. Therefore, if, for example, an ozone generator is connected to the ventilation pipe, the negative pressure causes ozone to be sucked into the ventilation pipe and ejected from the gas ejection hole. Ozone ejected from the gas ejection holes generates extremely fine bubbles in the treated water in the lower part of the first tank body by the vortex flow and the shearing force of the blades.

The water-bloom and the like in the treated water are oxidatively decomposed and aggregated by ozone which is jetted out and dissolved in the treated water, and is pushed up to the water surface by the fine bubbles rising in the treated water. The water-bloom and the like floating on the water surface are collected by an appropriate means.

The fresh water from which the water-bloom and the like have been separated in the water-bloom and the like decomposition and separation section enters from the lower portion in the water-and-water decomposition and separation section to the lower portion in the first fresh water area. The fresh water that has entered the first fresh water area is supplied into the tank body from the lower side of the second tank body.

The fresh water supplied into the second tank is agitated by the agitating means in the ozone decomposing zone partitioned by the second partition member. As a result, the self-decomposition of ozone in the liquid is promoted.

The treated water from which ozone has been removed in the ozone decomposing area enters from the lower part in the ozone decomposing area to the lower part in the second fresh water area and is returned to a lake or the like through a return pipe.

A standing plate is provided around the blades of the first gas-liquid mixing device, and a water-bloom etc. separation and separation area where the first gas-liquid mixing device and the standing plate are present, and other parts According to the first partition member arranged in the first fresh water area so as to partition the inside of the first tank body, the ozone jetted into the treated water is sheared by the blades and the standing plate is used. Since ozone is also sheared, ozone has a greater effect of forming bubbles.

The agitating means has a plurality of gas ejection holes on the lower side of the ventilation pipe whose lower end is closed and blades along the ventilation pipe, and is rotated in the tank body to eject the gas. According to the second gas-liquid mixing device that ejects air from the holes, when the ventilation pipe rotates, a vortex flow is generated in the treated water and a negative pressure is generated in the treated water on the back side of the blade in the rotation direction. . Therefore, due to this negative pressure, air is sucked into the ventilation pipe and ejected from the gas ejection hole. The air ejected from the gas ejection holes is
Since it is efficiently dissolved in the treated water by the vortex and the shearing force of the blade, the self-decomposition efficiency of ozone in the treated water is further enhanced.

If the second gas-liquid mixing device is constructed so as to selectively eject ozone and air from the gas-liquid ejection hole, it will not be possible to complete the treatment with only the first tank body. When the treated water is heavily contaminated, ozone can also decompose and separate water-bloom and the like in the second tank. In this case, in the second tank body, the violent dirt reacts with ozone, whereby ozone is self-decomposed simultaneously with decomposition and separation of water-bloom and the like.

Further, in the biotreatment tank in the middle of the piping of the return pipe, bacteria are brought into contact with the fresh water before being returned from the second fresh water area to the lake or the like. This allows
The pollutants remaining in clear water are decomposed.

The above-described process is continuously repeated by the apparatus of the present invention, and most of the water-bloom and the like in lakes and marshes are removed. In the treatment process, since the blue water etc. in the treated water is decomposed and killed by the oxidizing action of ozone,
In the fresh water returned to lakes and marshes through the return pipe, water-blooms and the like do not reoccur in a short period of time.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a fluid circuit diagram showing an embodiment of the device of the present invention.

First, for example, a submersible pump 2 sucks up polluted lake water or the like (hereinafter referred to as "treated water") that needs to be treated to remove the water-bloom or the like from inside the lake or the like 1 polluted with water-bloom or the like. . In the figure, 3 is a water absorption pipe.
The water absorption pipe 3 communicates with the lower portion of the first tank body 4.

Inside the first tank body 4, there is provided a first gas-liquid mixing device 5 having the following structure. The first gas-liquid mixing device 5 is arranged in the first tank body 4 directly above a portion where the treated water is discharged.

The first gas-liquid mixing device 5 is a known device disclosed in, for example, Japanese Examined Patent Publication No. 62-34436. For example, as shown in FIG. A ventilation pipe 8 having a plurality of gas ejection holes 7 on its side, and a ventilation pipe 8 extending along the ventilation pipe 8.
And a closing plate 10 for closing the lower end opening of the ventilation pipe 8.

The first gas-liquid mixing device 5 is connected to the rotating mechanism 11 at the top of the ventilation pipe 8 and is rotated about the axis of the ventilation pipe 8. When the ventilation pipe 8 rotates, a swirl flow is generated in the treated water by the action of the blades 9, and a negative pressure is generated in the treated water on the back side of the blades 9 in the rotation direction. Therefore, if the ozone generator 12 is connected to the gas inlet 6 of the ventilation pipe 8, ozone is sucked into the ventilation pipe 8 by the negative pressure and ejected from the gas ejection hole 7.

The ozone generator 12 has a structure known per se, which produces ozone by performing silent discharge through oxygen.

Ozone ejected from the gas ejection holes 7 produces extremely fine bubbles in the treated water in the lower portion inside the first tank body 4 due to the vortex flow and the shearing force of the blades 9.

Around the first gas-liquid mixing device 5, the inside of the first tank 4 is divided into the Aoko decomposition and separation area A1 in which the first gas-liquid mixing device 5 is present, and other parts. The 1st partition member 13 which partitions off with the 1st fresh water area A2 is provided. At the lower part of the partition member 13, both the areas A1,
A communicating portion 13 for communicating the A2s with each other at their lower portions.
a is provided.

In this embodiment, as shown in FIG. 2, a box-shaped first tank body 4 has a cylindrical partition member 1 smaller than it.
3 is fixed. A hole 13b that forms the communication portion 13a is provided in the lower portion of the partition member 13. In addition, a tubular partition member is fixed so that its lower end extends to the vicinity of the bottom of the first tank body 4 but does not reach the bottom, and the lower end of the partition member and the first tank body are fixed. The communication portion 13a may be formed between the bottom portion of the first tank body 4 and the bottom portion of the first tank body 4, and one partition member may be provided so as to partition the inside of the first tank body 4 into left and right parts. May be

On the lower part of the partition member 13, a stand plate 14 is fixed inward. This stand 14
By the action of the first gas-liquid mixing device 5, the ozone jetted as a vortex into the treated water is sheared to more efficiently perform the ozone atomizing action.

The water-bloom and the like in the treated water are oxidatively decomposed and aggregated by the ozone which is jetted out and dissolved in the treated water, and is pushed up to the water surface by the fine bubbles rising in the treated water. The water-bloom and the like floating on the water surface are recovered in the separation waste liquid tank 16 through the discharge pipe 15 by, for example, natural flow.

An appropriate not-illustrated scraping device for the water-bloom and the like is provided near the water surface of the water-blooming and decomposing / separating section A1, the device is connected to a motor, and the motor is operated at regular intervals by a timer. It is also possible to automatically collect the water-bloom and the like through the discharge pipe 15.

The treated water from which the water-bloom and the like have been removed as described above accumulates at the lower side of the water-bloom and the like decomposition and separation area A1 and passes through the communicating portion 13a to the first fresh water area A2.
Pour into.

A water level adjusting means 30 for adjusting the water level of the first tank body 4 is provided in the first fresh water area A2. As shown in FIG. 4, the water level adjusting means 30 includes two fixing plates 31 and 31 and these fixing plates 3
It is composed of two slide plates 32, 32 provided so as to be slidable up and down along 1, 31. The fixed plate 31 and the slide plate 32 are provided in a liquid-tight manner between the first tank body 4 and the partition member 13, and are completely in contact with the area A2 in the first fresh water area A2. A partitioned liquid chamber A3 is formed.

The slide plate 32 is, for example, a slide groove 33 provided so as to face the respective fixing plates 31 in the vertical direction.
Has a ridge portion 34 that conforms to the above, and the vertical position can be adjusted by hand. Appropriate resistance is provided between the slide groove 33 and the protrusion 34. Therefore, the slide plate 32 does not slide down after the vertical positioning.

A hole 35 is provided at the bottom of the first tank body 4 corresponding to the bottom of the liquid chamber A3, and the inside of the liquid chamber A3 will be described later with the transfer pipe 21 connected to the hole 35. The inside of the second tank body 20 communicates with each other.

In the liquid chamber A3, the treated water that has flowed into the first clear water zone A2 from the blue-green alga decomposition and separation zone A1 through the communication section 13a overflows from the upper end of the slide plate 32. Flow into. Therefore, the water level in the first tank body 4 does not exceed the height of the upper end portion of the slide plate 32. Therefore, the slide plate 3
By adjusting the vertical position of 2, the first tank body 4
The water level inside can be adjusted freely.

The upper portion of the first tank body 4 is completely sealed by the lid body 17 and is shielded from the atmosphere. This is because if a large amount of ozone leaks from the first tank body 4 for a long period of time, it will lead to environmental damage. The inside of the first tank body 4 is communicated with an appropriate ozone decomposition catalyst device 19 by a pipe 18 provided so as to penetrate the lid body 17. Ozone is decomposed into oxygen by the decomposition catalyst device 19 and then released into the atmosphere.

The above process is the process of decomposing and separating water-bloom and the like.

Next to the first tank body 4, a second tank body 20 is provided with its installation position lower than that of the first tank body 4. The liquid chamber A3 of the first tank body 4 has a transfer pipe 21
Through to the lower part of the second tank body 20. The treated water in the liquid chamber A3 is supplied into the second tank body 20 from below due to the difference in water level.

Inside the second tank body 20, a second gas-liquid mixing device 2 having the same structure as the first gas-liquid mixing device 5 is also provided.
2 are provided. The second gas-liquid mixing device 22 is
The second tank body 20 is arranged directly above a portion where the treated water is discharged.

The second gas-liquid mixing device 22 is for ejecting air in the atmosphere into the treated water in the second tank body 20. How the second gas-liquid mixing device 22 ejects air into the treated water is obvious from the description of the operation of the first gas-liquid mixing device 5 and will not be described.

The air ejected from the gas ejection holes 7 of the second gas-liquid mixing device 22 is polarized into the treated water in the lower portion inside the second tank body 20 by the vortex flow and the shearing force of the blades 9. Generates fine bubbles. As a result, ozone dissolved in the treated water in the process of decomposing and separating the water-bloom and the like efficiently comes into contact with air, and the ozone self-decomposes and returns to oxygen.

In the illustrated example, the second tank body 2 is considered in consideration of the case where contaminants such as water-bloom and the like are not sufficiently separated in the process of decomposing and separating the water-bloom and the like due to severe contamination of lake water and the like.
Even within 0, as in the case of the first tank body 4, it is considered that the decomposition and separation action of water-bloom and the like can be performed. The decomposition and separation action of the water-bloom and the like in the second tank body 20 can be performed alternatively with the self-decomposition effect of ozone described above. Which action is to be performed is determined according to the level of decomposition and separation of water-bloom and the like.

That is, two pipes 36 and 37 are connected to the second gas-liquid mixing device 22. One is a pipe 36 from the ozone generator 12 for taking in ozone, and the other is a pipe 37 whose free end side is open to the atmosphere for taking in air. Manual valves 38 and 39 are provided in the middle of the pipes 36 and 37, respectively. Then, when it is desired to perform the decomposition / separation action of the water-bloom and the like also in the second tank body 20, the atmosphere side valve 39 is closed and the ozone generator side valve 38 is opened. On the contrary, the second tank body 20
When it is not necessary to decompose and separate water-bloom and the like inside, the ozone generator side valve 38 is closed and the atmosphere side valve 39 is opened.

The ozone taken into the second tank body 20 is atomized by the action of the second gas-liquid mixing device 22 in the same manner as in the first tank body 4, and the ozone is removed. At the same time it decomposes, it pushes it up to the surface of the water. The pushed-up contaminants are discharged through the discharge pipe 25 into the separation waste liquid tank 1
Recovered within 6.

Generally, immediately after the purification treatment of lakes and the like is started, the treated water is heavily contaminated. Therefore, ozone is also supplied into the second tank 20 to decompose and separate water-bloom and the like. At this time, in the second tank body 20, ozone and the like efficiently react with ozone, so that ozone does not enter the lakes and marshes. When the treatment progresses and the water becomes clean, air is taken into the second tank body 20 to cause ozone to self-decompose. This prevents ozone from entering the lake or the like.

In the second tank body 20, when the decomposition and separation of water-bloom and the like and the self-decomposition of ozone are not selectively performed but only the self-decomposition of ozone is performed, the second gas-liquid mixture is used. Instead of the mixing device 22, for example, a stirring device having a simple structure including a propeller or the like may be used. However, from the viewpoint of the decomposition efficiency of residual ozone in the treated water, it is preferable to use the second gas-liquid mixing device 22 in which the air is atomized and automatically stirred into the treated water while stirring.

Around the second gas-liquid mixing device 22,
Inside the second tank body 20, the second gas-liquid mixing device 22
The second partitioning member 23 for partitioning the ozone decomposing area B1 in which is present and the second fresh water area B2 other than that is provided. The configuration of the partition member 23 is the same as the first partition member 1 described above.
3, the ozone decomposition zone B1 and the second fresh water zone B2 communicate with each other at their lower portions. The second partition member 23 is provided with a stand plate 40 like the first partition member 13. As a result, the action of separating and decomposing water-bloom or the like or the action of decomposing ozone in the ozone decomposing zone B1 is further promoted.

The treated water whose ozone has been decomposed in the ozone decomposing area B1 is connected to the communicating portion 2 below the areas B1 and B2.
After passing through 3a, it collects in the second fresh water zone B2.

The upper portion of the second tank body 20 is also completely sealed by the lid 24 for the same reason as the first tank body 4. The point that the inside of the second tank body 20 is communicated with an appropriate ozone decomposition catalyst device 19 is also the same as above.

The above process is the ozone decomposition process subsequent to the decomposition and separation process of the water-bloom and the like.

A return pipe 26 for returning the treated water in the fresh water area B2 to the lake 1 is connected to the second fresh water area B2. Then, a pump is used as necessary, and the treated fresh water is returned to the lake or the like 1.

A biotreatment tank 27 is provided in the middle of the return pipe 26.

In the biotreatment tank 27, the treated water is passed through the layer 28 of the porous material from the bottom to the top, and the treated water is brought into contact with the bacteria and the contaminants contained therein. Is decomposed. The porous material layer 2
In order to prevent dirt from adhering to 8, the air is exploded from the lower part of the porous material tank 28 as air bubbles. This also prevents the treated water from becoming anaerobic.

The above process is the biotreatment process following the ozone decomposition process.

By continuously repeating the above-mentioned processes, sewage from lakes and marshes is continuously purified.

[0071]

EFFECTS OF THE INVENTION According to the present invention, water-blooms and the like in lakes and marshes can be continuously removed. Therefore, unlike the conventional method of batch processing, water-blooms and the like can be efficiently separated. Moreover, since the water-blooms and the like do not survive in the fresh water returned to the lakes and marshes after the treatment due to the oxidizing action of ozone, there is an advantage that the re-generation of the water-blooms and the like in the lakes and marshes can be delayed.

Further, unlike the conventional one, since the coagulant is not used, the troublesome work such as adjusting the addition amount of the coagulant is not necessary, and the uncleaned mechanical treatment of the sewage can be performed.

Furthermore, since the treatment is always carried out under normal pressure, it is economical because it does not require energy for pressurization as in the conventional case.

[Brief description of drawings]

FIG. 1 is a fluid circuit diagram according to an embodiment of the device of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a perspective view showing an example of a gas-liquid mixing device.

FIG. 4 is a perspective view around the water level adjusting means in the first tank body.

[Explanation of symbols]

 1 Lakes, etc. 2 Pump 4 First tank body 5 Gas-liquid mixing device 7 Gas ejection hole 8 Vent pipe 9 Blade 13 First partition member 14 Stand plate 20 Second tank body 22 Stirring means (second gas-liquid mixing) 23) Second partition member 26 Return pipe 27 Bio treatment tank A1 Decomposition / separation area for Aoko etc. A2 First fresh water area B1 Ozone decomposition area B2 Second fresh water area

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C02F 3/02 ZAB A (72) Inventor Noriyoshi Kosaka 3-1, Okawa, Kanazawa-ku, Yokohama Tokyu vehicle Manufacturing Environmental Project (72) Inventor Fumitoshi Kadowaki 3-1, Okawa, Kanazawa-ku, Yokohama Tokyu Vehicle Manufacturing Environmental Project, Inc.

Claims (6)

[Claims] 1. A pump (2) for sucking treated water containing water-bloom etc. from a lake (1), and a first tank body (4) for receiving the treated water from the pump (2) at its lower side. , A plurality of gas ejection holes (7) and a blade (9) extending along the ventilation pipe (8) on the lower side of the ventilation pipe (8) whose lower end is closed, and the first tank body (4) ), And a first gas-liquid mixing device (5) for ejecting ozone from the gas ejection hole (7) and the inside of the first tank body (4). The area (A1) in which the mixing device (5) is present is separated into the first separation area (A2) of fresh water and the other areas (A1) and (A2) are divided by their lower parts. A first partition member (13) that allows them to communicate with each other, and the fresh water in the first fresh water area (A2) on the lower side thereof. Receiving a second tank body (20), the second tank body (20) stirred provided in the means (2
2) and the inside of the second tank body (20) are divided into an ozone decomposition zone (B1) where the stirring means (22) exists and a second fresh water zone (B2) other than that, and both Area (B
1), a second partition member (23) that allows the lower parts of the (B2) to communicate with each other, and a return pipe (26) that returns the fresh water in the second fresh water zone (B2) to a lake or the like. A sewage purification device that includes a water-bloom, etc. 2. A first tank body (4) for receiving treated water containing water-bloom and the like at a lower side thereof, and a plurality of gas ejection holes (7) at a lower side portion of a ventilation pipe (8) having a closed lower end. ) And a blade (9) along the ventilation pipe (8), and is rotated in the first tank body (4) to eject ozone from the gas ejection hole (7). Gas-liquid mixing device (5)
And the inside of the first tank body (4) is divided into an Aoko decomposition and separation zone (A1) where the first gas-liquid mixing device (5) is present and a first fresh water zone (A2) other than that. With the partition
The first partition member (13) that allows the lower parts of the both areas (A1) and (A2) to communicate with each other, and decomposes the water-bloom and the like contained in the treated water in the water-bloom-and-water decomposition and separation tank. And a separation process such as water-blowing and the like, a second tank body (20) for receiving the fresh water in the first fresh water area (A2) at its lower side, and this second tank body (20)
Inside the second tank body (20) and the stirring means (22) provided therein, an ozone decomposition area (B1) in which the stirring means (22) is present and a second fresh water area (B2) other than that. )
In addition to partitioning into both areas (B1), (B2)
An ozone decomposing process for decomposing ozone in an ozone decomposing tank comprising a second partition member (23) for communicating the insides thereof with each other at their lower parts, and the liquid in the second fresh water zone (B2) A method for purifying sewage containing water-bloom, etc., which sequentially performs a biotreatment process in which bacteria are contacted with. 3. A standing plate (14) is arranged around the blade (9) of the first gas-liquid mixing device (5), and the first gas-liquid mixing device (5) and the standing plate are arranged. The first partition member so as to partition the inside of the first tank body (4) into a decomposition / separation area (A1) in which (14) exists and a first fresh water area (A2) other than that. (13) is provided, The purification apparatus or the purification method of sewage containing the water-bloom etc. of Claim 1 or 2. 4. The stirring means (22) comprises a plurality of gas ejection holes (7) at the lower side of the ventilation pipe (8) whose lower end is closed, and vanes (9) extending along the ventilation pipe (8). The second gas-liquid mixing device (22), which has the following: and is rotated in the second tank body (20) to eject air from the gas ejection hole (7). Or the purification device or the purification method of sewage containing the water-bloom etc. described in 3. 5. The water-bloom or the like according to claim 4, wherein the second gas-liquid mixing device (22) selectively ejects ozone and air from the gas-liquid ejection hole (7). Sewage purification device or method. 6. The biotreatment tank (27) for bringing bacteria into contact with fresh water returned to a lake (1) is provided in the middle of the return pipe (26). Purification device for sewage that contains watermelon etc.