JP2000288575A - Wastewater treatment method and apparatus - Google Patents

Abstract

(57) [Problem] To make it possible to easily wash a membrane unit and to continue treatment of raw water at the time of washing the membrane unit. SOLUTION: An activated sludge tank in which a membrane unit 1 is immersed and installed therein is divided into a plurality of independent unit tanks 4a, 4b, 4c which can be individually operated and stopped. The operation of only the unit tank that requires cleaning of the membrane unit 1 is stopped, the activated sludge inside is transferred and emptied, and then the membrane unit 1 is washed in the empty unit tank. The remaining unit tanks continue to process raw water without stopping operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wastewater treatment method and apparatus for treating wastewater in an activated sludge tank by a high-concentration activated sludge method.

[0002]

2. Description of the Related Art As an example of a wastewater treatment apparatus employing the activated sludge method, as shown in FIGS.
A membrane unit 1 comprising a large number of hollow fiber membrane separation membranes 2 assembled at required intervals and connected to a filtration water pipe 3 to these separation membranes 2 is immersed in activated sludge 13 in an activated sludge tank 4. Then, the treated water suction pump 5
Connected to the treated water pipe 6 provided with
The diffuser tubes 7 are arranged in multiple rows below the
In the configuration in which the activated sludge tank 4 is equipped with an aeration device by being connected to the blower 8 via the aeration pipe 9, the raw water in the raw water tank 10 is supplied to the activated sludge tank 4 through the raw water pipe 12 by driving the raw water pump 11. The raw water and the activated sludge 13 are mixed and stirred by blowing air through the air diffuser 7 to oxidize and decompose the organic matter in the raw water into the activated sludge 13, and then suck the treated water. By the suction force of the pump 5, the treated water as filtered water filtered through the separation membrane 2 is collected in the treated water tank 14 through the filtered water pipe 3 and the treated water pipe 6, so that microorganisms and suspended substances can be separated. Are separated on the surface.

[0003] In the case of such a wastewater treatment apparatus, as described above, only the clarified filtered water is sucked by the separation membrane 2 of the membrane unit 1, and microorganisms and suspended substances are maintained in the activated sludge tank 4 to obtain a high concentration. Activated sludge treatment is realized, but in order to maintain this treatment efficiently, when clogging occurs due to solids accumulating on the surface of the separation membrane 2 of the membrane unit 1 as a cake layer. It is necessary to clean the membrane unit 1.

Conventionally, the membrane unit 1 is entirely lifted from the activated sludge tank 4 and washed with water, or the lifted membrane unit 1 is transferred and immersed in a chemical tank. Has been adopted.

[0005]

However, when the membrane unit 1 is lifted, the connection between the filtered water pipe 3 and the treated water pipe 6 of the membrane unit 1 must be separated or reconnected each time. The operation becomes complicated, and the separation membrane 2 may be damaged.
When transferring the water, not only there is a problem that sludge containing water adhering to the separation membrane 2 drops and stains the surroundings, but also there is a problem that the entire configuration of the cleaning device becomes large-scale.

[0006] A wastewater treatment apparatus capable of cleaning a membrane unit without lifting and transferring the membrane unit is disclosed in Japanese Patent Publication No. 6-83.
Although there are those disclosed in JP-A-838 and JP-A-8-252599, these wastewater treatment apparatuses have a problem that raw water cannot be treated while the membrane unit is being washed.

Therefore, the present invention makes it possible to easily wash the membrane unit without lifting or transferring the membrane unit, and to continue the treatment of raw water even while the membrane unit is being washed. It is an object of the present invention to provide a wastewater treatment method and apparatus that can be carried out by performing the method.

[0008]

According to the present invention, in order to solve the above-mentioned problems, raw water and activated sludge are agitated and mixed by aeration and filtered through a membrane unit installed immersed in the activated sludge inside. The activated sludge tank for discharging the treated water to the outside is divided into a plurality of unit tanks, and the operation and stop of each of the unit tanks are independently performed, so that at least one of the units is operated. The operation of the tank is stopped alone, the activated sludge inside is transferred to another tank and emptied, and then the membrane unit is washed in the empty unit tank, and the wastewater treatment is performed in another unit tank. By adopting the wastewater treatment method that is performed continuously, the membrane unit can be easily washed in an empty unit tank without being lifted or transferred.

During normal operation, the operation of each unit tank is stopped at a high water level and restarted at a low water level, so that activated sludge in the unit tank which requires cleaning of the membrane unit is removed. When the membrane unit is transferred to another unit tank and the membrane unit is washed in the empty unit tank, the wastewater treatment is continuously performed in the other unit tank to transfer the activated sludge to the unit tank. It is not necessary to provide a special tank.

Further, an activated sludge tank for stirring and mixing raw water and activated sludge by aeration and discharging treated water filtered through a membrane unit installed and immersed in the activated sludge inside, is provided with a wastewater tank. Is divided into one or more unit tanks more than the number required for treating the wastewater, and the operation and the stoppage of each unit tank are independently performed, so that the number of units required for the wastewater treatment is A wastewater treatment method in which only the tank is filled with activated sludge and the unit tanks not filled with activated sludge are sequentially replaced to wash the membrane unit, and the wastewater treatment is continuously performed in the unit tank filled with activated sludge. By doing so, it is possible to always treat a constant flow of wastewater.

Furthermore, by using a portable submersible pump for transferring activated sludge, it is not necessary to perform complicated piping and piping operations for transferring activated sludge.

On the other hand, an activated sludge tank for stirring and mixing raw water and activated sludge by aeration and immersing it in the activated sludge therein and filtering out the treated water through a membrane unit installed therein is separately provided. By dividing into a plurality of unit tanks that can be operated and stopped, a wastewater treatment apparatus having a configuration in which the operation of another unit tank can be continued even when the operation of one unit tank is stopped, The operation of only the unit tank in which the membrane unit requiring cleaning is installed is stopped, the membrane unit can be washed, and the operation in another unit tank can be continued.

[0013] Further, by making the number of divisions of the unit tank one or more larger than the number required for treating wastewater, the operation of one unit tank for cleaning the membrane unit is performed. Even if the operation is stopped, a predetermined amount of wastewater can be treated by operating other unit tanks.

Further, as means for independently operating and stopping each unit tank, a raw water pipe having an opening / closing device and a treated water pipe having an opening / closing device are connected to each unit tank. In addition, it is possible to easily supply raw water and recover treated water for each unit tank.

Further, since each unit tank is made of resin, it is easy to increase and relocate the unit tanks.

Further, by providing a submersible pump guide for dropping a portable submersible pump into a predetermined position in each unit tank, activated sludge in the unit tank for cleaning the membrane unit can be removed by another unit tank. When a portable submersible pump is used to transfer the submersible pump to the tank, the submersible pump can be set at a predetermined position by dropping the submersible pump along the submersible pump guide into the unit tank.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1A and 1B show an embodiment of a wastewater treatment apparatus according to the present invention. In the wastewater treatment apparatus having the same configuration as that shown in FIGS. A plurality of (eg, three) activated sludge tanks for stirring and mixing the activated sludge with aeration and discharging the treated water filtered through the membrane unit 1 immersed and installed in the activated sludge inside are provided. Resin unit tanks 4a, 4
b, 4c, the raw water pipe 12, the treated water pipe 6, and the aeration pipe 9 are branched and connected to each of the unit tanks 4a, 4b, 4c. Valves 15a, 15b, 15c as devices are
Further, valves 16a, 16b and 16c as opening / closing devices are provided in a branch pipe portion of the treated water pipe 6, and valves 17a, 17b and 17 as opening / closing devices are provided in a branch pipe portion of the aeration pipe 9.
c, respectively, and each unit tank 4a, 4b, 4c
Can be started and stopped independently.

Further, each of the unit tanks 4a, 4b, 4c
Has the same configuration as that shown for the unit tank 4a in FIG. That is, each unit tank 4a, 4b, 4
c, a suction start level switch 18, a load stop level switch 19, a load start level switch 20, and a suction stop level switch 21 are installed on the side wall of the water tank 4 'in order from the top to start suction and load. Four levels of stop, load start, and suction stop are set, and during normal operation, the operation of the treated water suction pump 5 is controlled based on signals from the suction start level switch 18 and the suction stop level switch 21. At the same time, the raw water pump 11 is operated based on the signal of the load start level switch 20, and the operation of the raw water pump 11 is stopped based on the signal of the load stop level switch 19. The water level is maintained even when the amount of water discharged is different.

Further, as shown in FIG. 1 (b), each of the unit tanks 4a, 4b, 4c is provided with a submersible pump guide 23 for dropping the portable submersible pump 22 to a predetermined position.

The unit tank has a division number equal to a number obtained by adding 1 to a number obtained by dividing the volume required for treating the target raw water by n. In the present embodiment, n is set to 2 and three equal volumes are set. These are unit tanks 4a, 4b, and 4c.

In FIGS. 1A and 1B, FIG.
(A) The same parts as (b) are denoted by the same reference numerals.

In the wastewater treatment apparatus having the above configuration, 3
Of the two unit tanks 4a, 4b, and 4c, two units are usually filled with the activated sludge 13 for operation, and the remaining one unit is stopped for operation. The membrane unit 1 is washed by filling it with the washing liquid without being filled, and when the washing is completed, the washing waste liquid is discharged to stand by for the next operation.
The activated sludge 13 in the unit tank in which the membrane unit 1 to be washed is installed is transferred to the unit tank in which the washing of the membrane unit 1 has been completed to be operated, and the operation is stopped. The operation of transferring the sludge 13 to another unit tank and washing the membrane unit 1 in the empty unit tank is sequentially switched so that the treatment of raw water at a constant flow rate is always maintained.

More specifically, in FIG. 1A, for example, it is assumed that the unit tank 4a is in operation and the unit tank 4a is in operation.
In the case where b is to start a new operation and the unit tank 4c is to start a new cleaning, first, the valves 17b and 17c of the aeration pipe 9 are closed, and the portable submersible pump 22 is placed in the unit tank 4c. After the washing, the cleaning waste liquid in the unit tank 4c is discharged and the valve 15c of the raw water pipe 12 is discharged.
And the valve 16c of the treated water pipe 6 is closed, and the submersible pump 2
2. Activated sludge in the unit tank 4c is removed by the unit tank 4b.
Transfer to Next, the valve 15b of the raw water pipe 12, the valve 17b of the aeration pipe 9, and the valve 16b of the treated water pipe 6
To start the operation by starting the flow of the raw water into the unit tank 4b and the discharge of the treated water. On the other hand, the portable submersible pump 22 is put into the treated water tank 14 and
Is transferred to the unit tank 4c as a cleaning liquid, and the membrane unit 1 is immersed in the treated water. In such a state, the valve 17c of the aeration pipe 9 is opened, and the membrane unit 1 in the unit tank 4c is aerated and cleaned for a certain time. The above operation is performed in three unit tanks 4
By successively switching between a, 4b, and 4c, raw water at a constant flow rate can always be treated using two of the three unit tanks 4a, 4b, and 4c. Also, from this, each unit tank 4a, 4
The loads on the membrane units 1 installed in b and 4c become uniform, and management becomes easy.

In the above description, the washing waste liquid after being used in the unit tank 4c is discharged. However, if the cleaning waste liquid has a property that can be used as a washing liquid, the washing liquid is temporarily put in another tank. Alternatively, when the raw water cannot be discharged as wastewater, the raw water may be combined in the raw water tank 10 or the like.

In the present embodiment, since the portable submersible pump 22 is used as a means for transferring activated sludge, the above processing can be performed without requiring complicated piping and complicated piping operations. . Also, each unit tank 4a, 4
b and 4c are provided with a submersible pump guide 23 for guiding the introduction of the submersible pump 22;
2 can be prevented from interfering with other structures in the unit tank or not reaching a position suitable for transferring activated sludge.

As described above, when the membrane unit 1 is washed, the membrane unit 1 is washed in the unit tank, which is a split type activated sludge tank, without being lifted or moved. Separation and connection work between the filtered water pipe 3 and the treated water pipe 6 is not required, and the entire cleaning work can be performed easily. Moreover, since the membrane unit 1 is not transferred, sludge containing water falls. Thus, the problem of soiling the surroundings can be solved, and the treatment of the raw water can be continuously performed when the membrane unit 1 is washed. Further, since the unit tank to be cleaned is small in comparison with the entire volume, the amount of activated sludge to be transferred can be small, and thus it is not necessary to prepare a large-scale tank at the transfer destination.
Similarly, when the cleaning liquid can be used repeatedly for several times of cleaning, the amount of waste liquid for cleaning decreases. Furthermore, besides aeration cleaning, various cleaning methods such as immersion cleaning in cleaning water or a chemical solution and cleaning by a water flow can be used, so that sludge attached to the membrane surface can also be cleaned. If a membrane that can be backwashed is used, backwashing can be performed. At this time, even if a chemical solution is used, it is discharged later, so that sludge is not affected.

In the above embodiment, the case where the activated sludge tank is divided into three unit tanks 4a, 4b and 4c has been described. However, the number of divisions is arbitrary, and in this case, a resin unit tank is employed. Thereby, addition and relocation can be easily performed.

Next, FIG. 2 shows another embodiment of the present invention. In the activated sludge tank, the number (2 in this embodiment) obtained by dividing the volume required for the treatment of the target raw water into n equal parts. Unit tank 4
a and 4b, for example, the unit tank 4
b, the activated sludge 13 in the unit tank 4b is transferred to the unit tank 4a to be concentrated, and the membrane unit 1 is emptied in the empty unit tank 4b.
Is performed. In FIG. 2, the same parts as those in FIG.

In the case of the embodiment shown in FIG. 2, the unit tank 4 to be continuously operated from the unit tank 4b (or 4a) to be cleaned.
The activated sludge 13 is transferred to a (or 4b) and concentrated in the unit tank 4a which continues the operation to increase the concentration of the activated sludge. At this time, when the sum of the transfer amount of the activated sludge 13 and the raw water injection amount is larger than the treated water amount, the raw water injection is stopped by the water level control by each level switch shown in FIG. Raw water can be injected only at a lower flow rate than usual, but if cleaning is performed during a time period when the raw water flow rate is low, no particular problem occurs as a whole apparatus, and a special transfer destination of the activated sludge 13 is not required. There is no need to provide a tank.

Next, as still another embodiment of the present invention, a configuration in which one or more sludge storage tanks (reservoir tanks) are added to the embodiment of FIG.

In this case, when the membrane unit 1 is washed, the activated sludge is transferred to the sludge storage tank and stored during the washing, so that the amount of the activated sludge used is minimized and the transfer destination tank is also small. . It is effective if there are two or more unit tanks, but the greater the number, the greater the effect because the required sludge storage tank is smaller. In addition, by equipping the sludge storage tank with an aeration device, the activated sludge can be kept healthy even when washing is performed for a long time.

FIG. 3 shows still another embodiment of the present invention. In a configuration similar to that of the wastewater treatment apparatus shown in FIG. 1A, the membrane units 1 of the unit tanks 4a, 4b, and 4c are used. Instead of branching and connecting the treated water pipe 6,
A treated water pipe 6a with a treated water suction pump 5a connected to the membrane unit 1 of the unit tank 4a is connected to the unit tank 4b.
A treated water pipe 6b with a treated water suction pump 5b connected to the membrane unit 1 of the unit tank 4b is connected to the unit tank 4c.
Further, a treated water pipe 6c with a treated water pump 5c connected to the membrane unit 1 of the unit tank 4c is connected to the treated water tank 14, and the treated water treated in the unit tank 4a is passed through the treated water pipe 6a. 4b, the treated water treated in the unit tank 4b is guided to the unit tank 4c, and the treated water treated in the unit tank 4c is collected in the treated water tank 14, and from the middle of the treated water pipe 6a. The branched treated water bypass pipe 6d is connected to the unit tank 4c.
Further, a treated water bypass pipe 6e branched from the middle of the treated water pipe 6b is guided to the treated water tank 14. The illustration of the aeration device is omitted. Also, the same parts as those in FIG.

In the wastewater treatment apparatus shown in FIG. 3, for example, when cleaning the membrane unit 1 in the unit tank 4a, the valve 15a is closed, and the operation of the treated water suction pump 5a is stopped. Activated sludge 1
3 is stopped by the portable submersible pump so far, the membrane unit 1 is transferred to the unit tank 4b or 4c where the washing of the membrane unit 1 is completed, and then the operation is restarted. At this time, the treated water treated in the unit tank 4b is led to the unit tank 4c through the treated water pipe 6b, and the treated water treated in the unit tank 4c is led to the treated water tank 14 through the treated water pipe 6c, so that the raw water is treated. Is continued. Next, when cleaning the membrane unit 1 in the unit tank 4b, the activated sludge in the unit tank 4b was transferred to the unit tank 4a, the valves 15b and 16a were closed, and the drive of the treated water suction pump 5b was stopped. As a state, the membrane unit 1 is washed in the unit tank 4b as described above. At this time, the treated water treated in the unit tank 4a is guided from the treated water pipe 6a to the unit tank 4c via the treated water bypass pipe 6d. When the membrane unit 1 in the unit tank 4c is cleaned, the cleaning is performed after the unit tank 4c is emptied as described above. From treated water bypass pipe 6e
Through the treatment water tank 14.

As described above, also in the wastewater treatment apparatus shown in FIG. 3, the treatment of the raw water can be continued when the membrane unit 1 is washed.

FIG. 4 shows still another embodiment of the present invention. In a configuration similar to the wastewater treatment apparatus shown in FIG. 1A, a portable submersible pump for transferring activated sludge 13 is shown. Instead of using a special pipe, a dedicated pipe is provided. That is, activated sludge transfer pipes 26 and 27 each having a pump 24 and a valve 25 are connected in reverse between the unit tanks 4a and 4b, and a pump 28 and a valve are connected between the unit tanks 4a and 4c. Activated sludge transfer pipes 30 and 31 each having 29 are connected in opposite directions. Other parts are the same as those shown in FIG. 1A, and the same parts are denoted by the same reference numerals. The illustration of the aeration device is omitted.

In the wastewater treatment apparatus shown in FIG. 4, for example, when cleaning the membrane unit 1 in the unit tank 4a,
The activated sludge 13 in the unit tank 4a is transferred to the activated sludge transfer pipe 2
When the membrane unit 1 in the unit tank 4b is to be transferred to the unit tank 4b or 4c using the 6 or 30 and the activated sludge 13 in the unit tank 4b is to be washed using the activated sludge transfer pipe 27, 4a
When cleaning the membrane unit 1 in the unit tank 4c, the activated sludge 13 in the unit tank 4c is transferred to the unit tank 4a using the activated sludge transfer pipe 31. Thereby, the treatment of raw water can be continued in the unit tank in which the membrane unit 1 is not washed.

In the embodiment shown in FIG. 4, if a height difference is provided between the unit tank 4a and the unit tanks 4b and 4c, the activated sludge 13 can be transferred by gravity difference. The pump 24 of one of the sludge transfer pipes 26 and 27 and the pump 28 of one of the activated sludge transfer pipes 30 and 31 can be omitted.

In the above embodiment, the case where the raw water pipe 12, the aeration pipe 9 and the like are branched and connected to each unit tank has been described. In addition, the unit tank is not limited to a resin tank, but may be one or more tanks having the same function as a tank generally used as a high-concentration activated sludge tank made of metal or reinforced concrete, or having the same function. A tank may be used, and the aeration device may include a blower 8
In place of the combination of the aeration pipe 9 and the aeration pipe 7, various known aeration devices can be used.
As the separation membrane 2 of the membrane unit 1, a known membrane such as a tubular membrane or a flat membrane can be arbitrarily used, and the material and the pore size can be selected according to the application, and other conditions can be used without departing from the gist of the present invention. Of course, various changes can be made.

[0040]

As described above, according to the wastewater treatment method and apparatus of the present invention, the following various excellent effects are exhibited.

(1) An activated sludge tank for stirring and mixing raw water and activated sludge by aeration and discharging treated water filtered through a membrane unit installed and immersed in the activated sludge inside, It is divided into a plurality of unit tanks, and the operation and stop of each of the unit tanks are performed independently, so that the operation of one or more of the unit tanks is stopped independently, and the activated sludge inside is removed. Since it is a wastewater treatment method in which the membrane unit is washed in the empty unit tank after the transfer to the empty tank and the wastewater treatment is continuously performed in another unit tank, the method is complicated. The membrane unit can be washed without requiring complicated facilities and heavy labor, and without contaminating the surroundings or damaging the membrane unit, continuing the treatment of wastewater, and transferring activated sludge. Destination The tank to be used is small.

(2) In the above-described wastewater treatment method, during normal operation, the operation of each unit tank is stopped at a high water level and restarted at a low water level, and the membrane unit needs to be washed. By transferring activated sludge in the unit tank to another unit tank and cleaning the membrane unit in the empty unit tank, the wastewater treatment in the other unit tank can be continued. In addition, there is no need to prepare a special tank for transferring activated sludge.

(3) An activated sludge tank for mixing raw water and activated sludge by aeration while stirring and discharging treated water filtered through a membrane unit installed and immersed in the activated sludge to the outside, It is divided into one or more unit tanks more than the number required for treating wastewater, and operation and shutdown are performed independently for each unit tank. A wastewater treatment method in which only unit tanks are filled with activated sludge and the unit tanks not filled with activated sludge are sequentially replaced to wash the membrane unit, and the wastewater treatment is continuously performed in the unit tank filled with activated sludge. By doing so, a constant amount of raw water can always be treated even during cleaning of the membrane unit.

(4) In each of the above wastewater treatment methods, by using a portable submersible pump for transferring activated sludge, the activated sludge can be transferred without complicated piping and piping operations. Can be.

(5) An activated sludge tank for mixing and stirring raw water and activated sludge by aeration and discharging the treated water filtered through a membrane unit installed and immersed in the activated sludge inside, Since it is a wastewater treatment apparatus having a configuration in which it is divided into a plurality of unit tanks that can be individually operated and stopped, and the operation of another unit tank can be continued even if the operation of one unit tank is stopped, Cleaning of the membrane unit can be performed by stopping the operation of only the unit tank in which the membrane unit requiring cleaning is installed, and therefore, stopping the operation of the unit tank in order to clean the membrane unit. By doing so, the treatment of raw water can be continued in the remaining unit tanks.

(6) In the above-mentioned wastewater treatment apparatus, the number of divisions of the unit tank is set to be one or more larger than the number required for treating the target wastewater, so that the membrane unit can be cleaned. Even if the operation of one unit tank is stopped, a predetermined amount of raw water can be treated by operating the remaining unit tanks.

(7) In the above wastewater treatment apparatus, as means for independently operating and stopping each unit tank, each unit tank is provided with a raw water pipe having an opening and closing device and a treated water pipe having an opening and closing device. By employing the connected configuration, the supply of raw water to each unit tank and the recovery of treated water can be easily performed.

(8) In the above wastewater treatment apparatus, the unit tanks are made of resin, so that the unit tanks can be easily added or relocated.

(9) In the above wastewater treatment apparatus, by adding a structure in which a submersible pump guide for dropping a portable submersible pump into a predetermined position is added to each unit tank,
When the portable submersible pump used for transferring activated sludge is dropped into the unit tank along the submersible pump guide, the submersible pump can be set at an appropriate position without causing interference with other structures. .

[Brief description of the drawings]

FIG. 1 shows an embodiment of a wastewater treatment apparatus according to the present invention, in which (A) is a schematic side view of the whole, and (B) is an enlarged schematic view showing a unit tank portion.

FIG. 2 is a schematic side view showing another embodiment of the present invention.

FIG. 3 is a schematic side view showing still another embodiment of the present invention.

FIG. 4 is a schematic side view showing still another embodiment of the present invention.

FIG. 5 shows an example of a wastewater treatment apparatus, wherein (a) is a schematic plan view of the whole, and (b) is a partially cut perspective view showing an enlarged activated sludge tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Membrane unit 4a, 4b, 4c Unit tank 6 Treated water piping 12 Raw water piping 13 Activated sludge 15a, 15b, 15c Valve (switching device) 16a, 16b, 16c Valve (switching device) 22 Submersible pump 23 Submersible pump guide

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Sakae Fukunaga 1 Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture F-term in the Technical Research Institute, Kawashima-Harima Heavy Industries Co., Ltd. 4D006 GA02 HA93 KA12 KA44 KA67 KB22 KC13 KC14 PA02 PB08 PC64 4D028 BC13 BC17 BD00 BD17 CA01 CB08 CD05

Claims (9)

[Claims] A plurality of activated sludge tanks for mixing raw water and activated sludge with aeration by aeration and discharging treated water filtered through a membrane unit installed and immersed in the activated sludge to the outside. Of each unit tank, the operation and stop of each unit tank are performed independently, and the operation of any one or more unit tanks is stopped independently, and the activated sludge inside is removed by another unit tank. A method for treating wastewater, comprising transferring a film to a tank, emptying the membrane, cleaning the membrane unit in the empty unit tank, and continuously performing wastewater treatment in another unit tank. 2. During normal operation, the operation of each unit tank is
The inflow of raw water is stopped by the high water level, and restarted by the low water level.The activated sludge in the unit tank that requires cleaning of the membrane unit is transferred to another unit tank and The wastewater treatment method according to claim 1, wherein the wastewater treatment is continuously performed in another unit tank while the membrane unit is being washed. 3. An activated sludge tank, which mixes raw water and activated sludge by aeration by aeration and discharges treated water filtered through a membrane unit installed and immersed in the activated sludge to the outside, Is divided into one or more unit tanks more than the number required for treating the wastewater, and the operation and the stoppage of each unit tank are independently performed, so that the number of units required for the wastewater treatment is Only the tank is filled with activated sludge, the unit tanks not filled with activated sludge are sequentially replaced to wash the membrane unit, and the wastewater treatment is continuously performed in the unit tank filled with activated sludge. Wastewater treatment method. 4. The wastewater treatment method according to claim 1, wherein a portable submersible pump is used for transferring the activated sludge. 5. An activated sludge tank for mixing raw water and activated sludge by aeration while agitating and discharging treated water filtered through a membrane unit installed inside the activated sludge by being immersed therein. A wastewater treatment apparatus having a configuration in which a plurality of unit tanks that can be operated and stopped can be divided so that the operation of one unit tank can be stopped and the operation of another unit tank can be continued. . 6. The wastewater treatment apparatus according to claim 5, wherein the number of divisions of the unit tank is one or more than the number required for treating the wastewater. 7. A raw water pipe having an opening / closing device and a treated water pipe having an opening / closing device are connected to each unit tank as means for independently operating and stopping each unit tank. A wastewater treatment device as described. 8. The method according to claim 5, wherein each unit tank is made of resin.
The wastewater treatment apparatus according to 6 or 7. 9. The wastewater treatment apparatus according to claim 5, wherein each unit tank is provided with a submersible pump guide for dropping a portable submersible pump into a predetermined position.