WO2011001803A1

WO2011001803A1 - Filtration membrane module cleaning method and cleaning device

Info

Publication number: WO2011001803A1
Application number: PCT/JP2010/059779
Authority: WO
Inventors: 茂雄佐藤; 和宏豊岡
Original assignee: 株式会社明電舎
Priority date: 2009-07-03
Filing date: 2010-06-09
Publication date: 2011-01-06
Also published as: KR20120027492A; JP2011011173A; CN102470325B; SG176812A1; CN102470325A; KR101415678B1; JP5423184B2

Abstract

In a conventional in-air cleaning method and a cleaning device, a filtration membrane module is pulled out from a reaction tank and a chemical must be injected into the filtration membrane module that is exposed to air, therefore requiring a complicated work and large amounts of facility cost and installation space. To solve the above problems, according to the invention, a filtration membrane module (11) is cleaned in such a way that: the filtration membrane module (11) is housed in a module casing (27); air is introduced into the module casing (27), thereby filling the inside of the module casing (27) with the air; a cleaning chemical such as, for example, a sodium hypochlorite solution is injected into the secondary side of the filtration membrane module (11) while the filtration membrane module (11) is exposed to air; and the chemical is penetrated into the primary side of the filtration membrane module (11).

Description

Filtration membrane module cleaning method and cleaning apparatus

The present invention relates to a cleaning method and a cleaning apparatus for a filtration membrane module that performs a filtration operation by immersing a pollutant in sewage or industrial wastewater in a reaction tank for biological treatment or coagulation sedimentation treatment.

In a membrane separation treatment system that performs biological treatment or coagulation sedimentation treatment of pollutants in sewage and industrial wastewater, and filters them with a filtration membrane module, the filtration membrane module is immersed in a reaction tank and filtered water is filtered. Membrane separation.

By the filtration operation, the removed pollutant or the like adheres to and accumulates on the membrane surface of the membrane membrane module and the pores inside the membrane surface. Normally, in order to keep the filtration operation time longer and to improve the efficiency of the filtration operation by suppressing the adhesion and accumulation of pollutants on the membrane surface, aeration is performed from the bottom of the filtration membrane module, and intense bubble flow on the membrane surface. Scrubbing air is supplied in order to prevent adhesion and accumulation by colliding. At the same time, the filtered water is pressurized and passed through the membrane filter module at a fixed period to remove the dirt backwashing. However, there is a limit to the long-term suppression effect even by scrubbing air and backwashing. For this reason, in order to periodically remove contaminants that gradually adhere to and deposit on the film surface even by scrubbing air or backwashing, it is essential to perform chemical cleaning that reacts and removes the contaminants that adhere and deposit.

As the chemical solution, sodium hypochlorite is widely used when the pollutant or the like deposited or deposited is organic, and oxalic acid is used when it is inorganic.

And, in-line cleaning and on-air cleaning are known as a method for cleaning a membrane filter module using this chemical solution.

In-line cleaning is performed by injecting a chemical solution such as sodium hypochlorite solution from the secondary side (filtrated water removal side) of the filtration membrane module while the filtration membrane module immersed in the reaction tank is immersed. Is permeated and permeated into the primary side (filtered water supply side) of the filtration membrane module to perform chemical cleaning of the filtration membrane module (hereinafter referred to as a first cleaning method).

In the on-air cleaning method, a chemical solution such as a sodium hypochlorite solution is injected from the secondary side of the filtration membrane module while the filtration membrane module is exposed to the air, and the chemical solution is injected from the secondary side of the filtration membrane module. In this method, the filtration membrane module is permeated and permeated to the primary side to perform chemical cleaning.

Specifically, the following three methods are known as on-air cleaning methods.

The first is that the filtration membrane module is pulled out from the submerged reaction tank and exposed to the air, and a chemical solution such as a sodium hypochlorite solution is injected from the secondary side of the filtration membrane module, and the chemical solution is removed from the filtration membrane. In this method, the membrane filter is permeated and permeated from the secondary side to the primary side of the module to clean the filtration membrane module (hereinafter referred to as a second cleaning method).

The second is that the liquid in the tank is discharged from the reaction tank in which the filtration membrane module is immersed, and the filtration membrane module is exposed to the air in the reaction tank. This is a method of injecting a chemical solution such as a sodium chlorate solution and allowing the chemical solution to permeate and permeate the primary side of the filtration membrane module to wash the filtration membrane module (hereinafter, a third cleaning method).

The third is that, in the case of processing the pollutant and the like by an external immersion tank system provided with a tank dedicated to the filtration membrane module separately from the reaction tank, the chemical solution cleaning in this system is an external immersion tank. Since only the liquid in the tank needs to be discharged, the amount of the discharged liquid can be reduced as compared with the third cleaning method, and further, after taking a method of temporarily storing the discharged liquid in the reaction tank, The same chemical cleaning method as the third cleaning method can be used for the filtration membrane module (hereinafter referred to as a fourth cleaning method).
For example, Patent Document 1 discloses the above-described cleaning method.

JP 2005-66548 A

In the first cleaning method (in-line cleaning method), the chemical solution is injected in a state where the filtration membrane module is immersed in the liquid in the reaction tank. In addition, the chemical solution that has permeated and permeated on the surface of the filtration membrane module is diluted by the solution in the tank, so cleaning of contaminated substances attached to and deposited on the membrane surface of the filtration membrane module The effect is reduced. Moreover, when clogging has arisen in the filtration membrane module, the chemical | medical solution does not spread over this clogging part but a cleaning spot generate | occur | produces. In order to eliminate cleaning spots, a chemical solution must be injected into the filtration membrane module in a large amount at a higher pressure, which requires a high-pressure pump and a large amount of chemical solution.

In the second cleaning method (on-air cleaning method), it is necessary to use a lifting device such as a chain block in order to pull out the filtration membrane module from the reaction tank and move it in the air. It is necessary to perform complicated operations such as removing the scrubbing air pipe and installing it after completion of cleaning.

The third cleaning method (on-air cleaning method) requires a separate storage tank for temporarily storing the liquid in the tank extracted from the reaction tank. Usually, the filtration membrane module is immersed to the bottom of the reaction tank at a depth of 4 to 5 m. In order to expose the entire filtration membrane module to the air, almost all of the liquid in the reaction tank is drawn out. This leads to an increase in construction costs and operating costs due to the installation and installation of large capacity tanks and transfer pumps that temporarily store the liquid in the tank.

In the fourth cleaning method (on-air cleaning method), that is, in the external immersion tank method provided with a tank dedicated to the filtration membrane module separately from the reaction tank, only the liquid in the external immersion tank is discharged. As a result, the amount of the discharged liquid can be reduced as compared with the third cleaning method, and the discharged liquid can be transferred to the reaction tank and temporarily used as a storage tank. However, the construction cost and the operating cost are increased although they do not reach the apparatus by the third cleaning method, such as the installation of an external immersion tank and the need for a liquid transfer pump from the reaction tank to the external immersion tank.

The object of the present invention is to reduce the cleaning ability in the first cleaning method, to increase the pressure of the pump for injecting the chemical solution for this countermeasure, and to increase the amount of the chemical solution to be used. In the second cleaning method, The problem is that it requires lifting equipment such as a chain block to be moved to the air, and requires complicated work such as removal of filtered water piping and scrubbing air piping, etc., and installation after completion of cleaning. In this cleaning method, there are problems that require equipment such as a large-capacity tank for temporarily storing the extracted liquid in the tank and a transfer pump, and the fourth cleaning method is used for installation and transfer of an external immersion tank. Solves the problem of requiring a pump, and achieves the same high cleaning effect as the above-mentioned conventional on-air cleaning with the ease of in-line cleaning that chemically cleans the filtration membrane module while the filtration membrane module is immersed in the reaction vessel And to provide a filtration membrane module cleaning method and cleaning apparatus can.

The filtration membrane module cleaning method of the present invention injects a chemical solution for cleaning from the secondary side of the filtration membrane module placed soaked in a reaction tank, and permeates and permeates the chemical solution to the primary side of the filtration membrane module. In the filtration membrane module cleaning method for cleaning the filtration membrane module, the filtration membrane module is accommodated in a module casing (cleaning casing), and air, oxygen gas, carbon dioxide gas, nitrogen gas, etc. are easily handled as air in the module casing. Supply gas (hereinafter collectively referred to as air), the liquid in the tank is expelled from the module casing, and the filtration membrane module is subjected to chemical cleaning with the filtration membrane module in the module casing exposed to the air. .

The cleaning device for a filtration membrane module of the present invention includes a chemical solution injection device that injects a chemical solution for cleaning on the secondary side of the filtration membrane module that is immersed in a reaction tank. In a filtration membrane module cleaning apparatus that permeates and permeates a primary side of a filtration membrane module to wash the filtration membrane module, and stores the filtration membrane module in the air. A module casing capable of storing air to be exposed, and an air supply device for supplying air into the module casing to expose the filtration membrane module to the air are provided.

The module casing was formed into a covered cylindrical shape with the bottom opened and the top closed with a lid plate, and a liquid and air outflow valve for communicating the inside and outside of the module casing with the lid plate was provided. A pressure air drive valve was used as the liquid and air outflow valve.

An air blower or a scrubbing blower was used (also used) as an air supply device for supplying the module casing.

The filtration membrane module cleaning method of the present invention supplies the air into the module casing containing the filtration membrane module, and fills the inside of the module casing with air so that the filtration membrane module is exposed to the air. Since the chemical solution is injected into the secondary side of the filter membrane module, the filtration membrane module is not subjected to fluid pressure compared to the conventional in-line cleaning method in which the chemical solution is injected while the conventional filtration membrane module is immersed in the reaction vessel. Perhaps the chemical solution is easy to penetrate and permeate. The chemical liquid that has exuded from the pores on the membrane surface of the filtration membrane module does not react with the liquid in the tank and the effect of the chemical liquid does not decrease. Further, since the chemical solution is not diluted with the solution in the tank, the cleaning effect is not reduced by the dilution of the chemical solution. The filtration membrane module cleaning method of the present invention is implemented by adding a simple process of storing the filtration membrane module in the module casing and supplying air into the module casing to the conventional in-line cleaning method. be able to.

The filtration membrane module cleaning device of the present invention is simple to the conventional inline cleaning device in which the filtration membrane module of the conventional inline cleaning device is accommodated in the module casing and air is supplied to the module casing by the air supply device. It can be implemented by making improvements. Then, by supplying air into the module casing with the air supply device, the inside of the module casing is filled with air and the filtration membrane module is exposed to the air. In this state, the chemical solution is filtered by the chemical solution injector. The filtration membrane module can be washed on-air by being injected into the secondary side of the membrane module.

Particularly, since the module casing is formed in a covered cylindrical shape having an opening at the bottom and closed at the top by a lid plate, air can be supplied into the module casing from the opening by an air supply device. Since the liquid and air outflow valves are provided on the cover plate of the module casing, the liquid and air outflow valves can be opened and closed to store or discharge air in the module casing. Therefore, the operation system of the filtration membrane module cleaning device of the present invention can be formed by a simple improvement of adding the operation of opening and closing the liquid and air outflow valves to the operation system of the conventional in-line cleaning device.

In addition, the use of an air blower or scrubbing blower for the air supply device that is supplied into the module casing eliminates the need for a dedicated air compressor as an air supply device. Can be lowered.

The flowchart of the example of a sewage treatment system by the membrane separation activated sludge method (MBR) provided with the filtration membrane module washing | cleaning apparatus of this invention. The enlarged view of the filtration membrane module washing | cleaning apparatus part of this invention.

FIG. 1 is a flow diagram of a sewage treatment system using a membrane separation activated sludge method (MBR) equipped with a filtration membrane module cleaning device of the present invention. In this sewage treatment system, raw water 1 such as sewage and industrial effluent is introduced into a screen tank 2 and sent to a flow rate adjusting tank 4 in a state in which dust and the like are removed by a fine screen 3, and a pump is supplied from the flow rate adjusting tank 4 The flow rate is adjusted at 5 and sent to the denitrification tank 6, and the denitrification tank 6 is sent to the reaction tank 7 by natural flow due to the difference in water level. In addition, the return pump 8 returns the reaction tank 7 to the denitrification tank 6, and the activated sludge circulates between the denitrification tank 6 and the reaction tank 7, and a part thereof is extracted from the reaction tank 7 as excess sludge by the sludge extraction valve 9. It is.

In the denitrification tank 6, stirring is performed with an agitator 10 without oxygen. In addition, in the reaction tank 7, inflow water (hereinafter, filtered water) is biologically treated with activated sludge, filtered through a filtration membrane module 11 disposed in the reaction tank 7, and filtered water (hereinafter, filtered water). Water is sent to the filtrate water tank 13 through the filtration pipe 12, temporarily stored in the filtrate water tank 13, and then discharged from the filtrate water tank 13 by the pump 14.

The filtration membrane module 11 is a cylindrical hollow fiber membrane module such as polyvinylidene fluoride (PVDF). The filtration membrane module 11 performs filtration by allowing the solution in the reaction tank to permeate. One or more filtration membrane modules 11 are arranged in the reaction tank 7.

In the reaction tank 7, an aerobic treatment is performed in the presence of dissolved oxygen by an aeration blower (aeration blower) 15, and the filtration membrane module 11 is constantly vibrated by a scrubbing blower 16 and a scrubbing aerator 17. Thus, the filtration membrane module 11 is prevented from being blocked by activated sludge. Reference numeral 15a denotes an aeration diffuser.

A filtration / backwash pump 18 is provided in the middle of the filtration pipe 12. When the filtration / backwash pump 18 filters the water to be filtered, or when the filtrated membrane module 11 is backwashed and washed by supplying the filtrated water in the filtrated water tank 13 to the membrane filter module 11 every set time, It is used when the chemical solution is washed out after the filtration membrane module 11 is washed with the chemical solution by the chemical solution injection device 26 described later.

The filtration pipe 12 is provided with first and

second valves

19 and 20 on the upstream side (reaction tank 7 side) and the downstream side (filtrated water tank 13 side) with a filtration / backwash pump 18 interposed therebetween. . Further, the filtration pipe 12 is provided with a first filtered water reverse flow path 21 that connects the upstream side of the first valve 19 and between the filtration / backwash pump 18 and the second valve 20. A third valve 22 is provided in the first filtered water reverse flow path 21. Further, the filtration pipe 12 is provided with a second filtrate reverse flow path 23 connecting the filtration / backwash pump 18 and the first valve 19 and the filtrate water tank 13, and the second filtrate reverse flow path 23. Is provided with a fourth valve 24.

The filtration membrane module 11 is cleaned by a filtration membrane module cleaning device 25 described below.

As shown in FIGS. 1 and 2, the filtration membrane module cleaning device 25 includes a chemical solution injection device 26 that injects a cleaning chemical solution such as a sodium hypochlorite solution into the secondary side of the filtration membrane module 11 during module cleaning. A module casing (cleaning casing) 27 that can store the filtration membrane module 11 and expose the filtration membrane module 11 to the air, and an air supply device 28 that supplies air into the module casing 27 It is made up of.

The air supply device 28 also serves as a scrubbing blower 16, and the air is supplied into the module casing 27 from the opening at the bottom of the module casing 27 by positioning the scrubbing diffuser 17 at the bottom of the module casing 27. It is like that.

The chemical solution injection device 26 includes a chemical solution tank 29 containing a chemical solution for cleaning such as a sodium hypochlorite solution, a chemical solution supply pump 30, and a chemical solution supply path 31 for supplying the chemical solution in the chemical solution tank 29 to the filtration membrane module 11. And a fifth valve 32 provided in the chemical solution supply path 31. The chemical solution supply path 31 is connected to the upstream side (filtration membrane module 11 side) of the first filtered water reverse flow path 21.

The module casing 27 is made of a material such as an airtight metal that is hardly eroded by the chemical solution.

The module casing 27 is formed in a cylindrical shape having a diameter larger than the diameter of the filtration membrane module 11 and longer than the length of the filtration membrane module 11, and stores one or more filtration membrane modules 11.

Further, a liquid and air outflow valve 33 is provided at the upper part of the module casing 27.

The bottom of the module casing 27 is open and the top is closed with a lid plate. When the liquid and air outflow valve 33 is closed during chemical cleaning and air is supplied from the opening through the air supply device 28, the air removes the activated sludge (water to be filtered) in the module casing 27 and the module. The perimeter of the filtration membrane module 11 that is accumulated in the casing 27 and accommodated in the module casing 27 is covered with air.

On the other hand, the liquid and air outflow valve 33 is opened to discharge air from the module casing 27 so that the activated sludge can enter the module casing 27 and the module casing 27 is filled with the activated sludge. After that, the circulation property of the activated sludge between the inside and outside of the module casing 27 is ensured. It is desirable to use a pressure air drive valve for the liquid and air outflow valve 33. By providing a plurality of liquid and air outflow valves 33 instead of only one, it is possible to improve the speed of discharging the air inside the module casing 27 and the circulation of activated sludge inside and outside the module casing 27.

The position at which the liquid and air outflow valve 33 is provided is not necessarily the upper cover plate of the module casing 27, but can be discharged to a state where the filtration membrane module 11 is not exposed to the air accumulated in the module casing 27. Is good.

Next, the operation of the filtration membrane module cleaning device will be described. At the time of filtration, the fifth valve 32 of the chemical liquid injector 26 is closed, the liquid and air outflow valve 33 is opened, and the first and

second valves

19 and 20 provided in the filtration pipe 12 are opened to perform filtration / When the backwash pump 18 is driven, the water to be filtered in the reaction tank 7 is filtered by the membrane filter module 11 to become filtered water, sent to the filtered water tank 13 and temporarily stored.

When the filtration membrane module 11 is washed on-air, the diffuser blower 15 is stopped, the filtration / backwash pump 18 is stopped, the first and

second valves

19 and 20 are closed, and the liquid and air outflow valves are closed. 33 is closed. When the scrubbing blower 16 is driven, the air sent out from the scrubbing blower 16 enters the module casing 27 through an opening provided at the bottom of the module casing 27 via the scrubbing air diffuser 17, and enters the module casing 27. While removing the activated sludge in 27, it accumulates in the module casing 27.

When the inside of the module casing 27 is filled with air and the periphery of the filtration membrane module 11 accommodated in the module casing 27 is covered with air, the scrubbing blower 16 is stopped and the supply of air is stopped. .

If the stop time of the scrubbing blower 16 is delayed, the supplied air enters a so-called overflow state and leaks from the bottom of the module casing 27 to the outside of the module casing 27. Therefore, a simple timer setting is sufficient for the timing of stopping the air supply by the scrubbing blower 16 without strictly controlling.

Then, when the inside of the module casing 27 is filled with air and the filtration membrane module 11 is exposed to air, the fifth valve 32 is opened, the chemical solution supply pump 30 is driven, and the chemical solution in the chemical solution tank 29 is added to a predetermined amount, Over a predetermined time, it is injected into the filtration membrane module 11, and the filtration membrane module 11 is washed with a chemical solution.

When the cleaning with the chemical liquid is completed, the chemical liquid supply pump 30 is stopped, the fifth valve 32 is closed, and the third and

fourth valves

22 and 24 are closed while the first and

second valves

19 and 20 are closed. Open and drive the filtration / backwash pump 18 again to supply the filtrate water in the filtrate tank 13 to the filtration membrane module 11 via the second filtrate reverse flow path 23 and the first filtrate reverse flow path 21; By washing the filtration membrane module 11 with filtered water, the chemical solution remaining on the membrane surface of the filtration membrane module 11 is washed away, and the washing of the filtration membrane module 11 is completed. The washing step of the chemical solution may be performed after the activated sludge in the module casing 27 is filled.

When the filtration membrane module 11 has been cleaned, the liquid and air outflow valve 33 is opened. When the liquid and air outflow valve 33 is opened, the air in the module casing 27 passes through the liquid and air outflow valve 33 and is discharged out of the module casing 27, and activated sludge enters the module casing 27, The module casing 27 is filled with activated sludge. Therefore, the first and

second valves

19 and 20 are opened again, and the aeration blower 15, the filtration / backwash pump 18, the scrubbing blower 17 and the like are driven to resume the filtration. A timer setting is sufficient for returning to the filtration operation.

The filtration membrane module cleaning device of the embodiment has the above-described configuration and has the following effects.
(1) With a simple method of storing the filtration membrane module in the module casing and supplying air, it becomes possible to perform on-air cleaning while the filtration membrane module is immersed in the reaction tank. Compared with the method of discharging activated sludge from the tank or extracting the filtration membrane module from the reaction tank and performing on-air cleaning, the on-air cleaning of the filtration membrane module can be performed easily.
(2) The filtration membrane module can be individually washed on-air without removing the filtration membrane module in the air. When activated sludge is discharged from a conventional reaction tank and on-air cleaning is performed, and when multiple filtration membrane modules are installed in the reaction tank, all the installed filtration membrane modules cannot be used. In the case of the present invention, the filtration membrane module can be individually washed on-air (for each module casing), so other filtration membranes except for the membrane membrane being washed are removed. A membrane module can be used, and a stable amount of filtration can be ensured.
(3) Since the chemical membrane cleaning can be performed while the filtration membrane module is immersed in the reaction vessel, the filtration membrane module cleaning device can be easily incorporated into the automatic operation of the sewage treatment system. Accordingly, the chemical cleaning frequency can be set high, clogging of the filtration membrane module can be suppressed, and stable processing capability can be ensured.
(4) In the filtration membrane module cleaning device of the present invention, the specially added parts are a module casing for housing the filtration membrane module, a liquid and air outflow valve attached to the module casing, and an air source for valves. Can be manufactured inexpensively. In particular, if a scrubbing blower is used in an air supply device that supplies air to the module casing, the number of parts can be reduced and the cost can be reduced accordingly. Therefore, it can be manufactured at a much lower cost than a conventional on-air cleaning apparatus, and uses less energy.

In the above embodiment, the scrubbing blower 16 and the scrubbing air diffuser 17 are used for the air supply device 28, and the scrubbing air diffuser 17 is disposed facing the opening at the bottom of the module casing 27. Although the case where air is supplied into the module casing 27 is shown, it is not always necessary to supply air from the opening at the bottom of the module casing 27. For example, the air supply path 34 that connects the scrubbing blower 16 and the scrubbing air diffuser 17 is used. Alternatively, a branch path (not shown) may be connected to the module casing 27 via a switching valve (not shown), and the tip of the branch path may be connected to the module casing 27 to supply air into the module casing 27. When air is supplied from the branch path, the supply of air to the scrubbing air diffuser 17 is stopped by the switching valve. A check valve (not shown) is provided at the tip of the branch path. The position where the tip of the branch path is connected to the module casing 27 does not matter. In addition, air may be supplied into the module casing 27 by using the diffuser blower 15 instead of the scrubbing blower 16.

Further, a dedicated air supply blower may be used without using the scrubbing blower 16 or the diffuser blower 15. Moreover, although the case where the module casing 27 was formed in the covered cylinder shape was shown in the Example, the shape of the module casing 27 is not limited to a covered cylinder shape, It is made to respond | correspond to the shape of the filtration membrane module 11, etc. Thus, it is formed into an appropriate shape. In the embodiment, the single filtration / backwash pump 18 performs both backwashing and filtration, but the filtration and backwashing may be performed by separate pumps. Moreover, in the Example, although the case where cylindrical hollow fiber membrane modules, such as a polyvinylidene fluoride (PVDF), were used for the filtration membrane module 11, the material of the filtration membrane module 11 does not ask | require an organic membrane and an inorganic membrane. . The structure of the filtration membrane module 11 may be a flat membrane, a hollow fiber membrane, a single tube membrane, or the like. Moreover, in the said Example, although only the filtration membrane module washing | cleaning apparatus was demonstrated, in this description, a sodium hypochlorite solution etc. from the secondary side of the filtration membrane module arrange | positioned by being immersed in the reaction tank. In a filtration membrane module cleaning method of injecting a chemical solution and permeating the chemical solution into the primary side of the filtration membrane module to wash the filtration membrane module, the filtration membrane module is accommodated in a module casing, and air is introduced into the module casing. In the present invention, the chemical solution is injected into the secondary side of the filtration membrane module while the filtration membrane module is exposed to the air, and the chemical solution is allowed to permeate the primary side of the filtration membrane module. Filtration membrane module cleaning method is disclosed. Moreover, in the said Example, the membrane separation processing system which processes the pollutant in a sewage wastewater or industrial wastewater by biological treatment, and filters with the filtration membrane module for the filtration membrane module washing | cleaning method and filtration membrane module washing | cleaning apparatus of this invention. Although the case where it used was demonstrated, it can also be used for the membrane separation processing system which adds a coagulant | flocculant, carries out the coagulation precipitation process of a pollutant, etc., and filters with a filtration membrane module.

The present invention can be applied not only to a submerged membrane but also to a casing housing type membrane module.

DESCRIPTION OF SYMBOLS 1 ... Raw water 2 ... Screen tank 3 ... Rough screen 4 ... Flow adjustment layer 6 ... Denitrification tank 7 ... Reaction tank 8 ... Return pump 9 ... Sludge extraction valve 10 ... Stirrer 11 ... Filtration membrane module 12 ... Filtration piping 13 ... Filtration water Tank 15 ... Aeration blower (aeration blower)
15a ... Aeration diffuser 16 ... Scrubbing blower 17 ... Scrubbing diffuser 18 ... Filtration / backwash pump 19 ... First valve 20 ... Second valve 21 ... First filtered water backwash path 22 ... First 3 valve 23... First filtered water backwash path 24... 4th valve 25... Filtration membrane module cleaning device 26 .. chemical injection device 27 .. module casing (cleaning casing)
DESCRIPTION OF SYMBOLS 28 ... Air supply apparatus 29 ... Chemical liquid tank 30 ... Chemical liquid supply pump 31 ... Chemical liquid supply path 32 ... Fifth valve 33 ... Liquid and air outflow valve 34 ... Air supply path

Claims

A filtration membrane module cleaning method for injecting a chemical solution for cleaning from the secondary side of a filtration membrane module placed in a reaction tank and allowing the chemical solution to permeate the primary side of the filtration membrane module to wash the filtration membrane module In
The filtration membrane module is housed in a module casing, air is introduced into the module casing, and the chemical solution is injected from the secondary side of the filtration membrane module in a state where the filtration membrane module is exposed to the air. A filtration membrane module cleaning method, wherein a chemical solution is allowed to permeate the primary side of the filtration membrane module.
It is equipped with a chemical injection device that injects a chemical solution for cleaning on the secondary side of the filtration membrane module that is immersed in the reaction vessel, and the filtration membrane module is injected into the secondary side of the filtration membrane module by the chemical injection device to clean the filtration membrane module. In the filtration membrane module cleaning device
A module casing capable of storing the filtration membrane module and storing air for exposing the filtration membrane module to the air, and an air supply for supplying air into the module casing to expose the filtration membrane module to the air And a filtration membrane module cleaning device.
The filtration membrane module cleaning device according to claim 2, wherein the module casing has an opening at the bottom, closed at the top by a cover plate, and a liquid and air outflow valve provided on the cover plate.
4. The filtration membrane module cleaning device according to claim 3, wherein the liquid and air outflow valves are pressure air drive valves.
The filtration membrane module cleaning device according to any one of claims 2 to 4, wherein the air supply device is also used as a scrubbing blower or an aeration blower.