JP2004249204A - Backwashing method of membrane module - Google Patents

Abstract

An object of the present invention is to provide a method of backwashing a membrane module, which can reduce troublesome valve operation at the time of backwash.
When a backwash is performed, a backwash pressure pump is operated to close a supply valve, a backwash discharge valve, and a discharge valve, and a backwash supply valve is opened. The washing water is supplied into the casing 11 from the filtered water discharge port 25 to pressurize the inside of the casing 11, and thereafter, when the pressure in the casing 11 is increased to a predetermined pressure, the backwash discharge valve 41 is suddenly opened. As a result, the raw water supply port 14 side is opened, and the pressure inside the casing 11 is rapidly reduced. In this state, the backwash water is continuously supplied from the filtered water discharge port 25 into the casing 11 by the backwash pressure pump 43. The water is supplied to backwash the membrane element, and is discharged from the raw water supply port 14 to the outside of the casing 11.
[Selection diagram] Fig. 4

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a backwashing method for a membrane module which is discharged from a discharge unit to the outside of a casing as a filtration processing fluid after a fluid to be treated supplied from a supply unit into the casing is filtered by a membrane element in the casing. .
[0002]
[Prior art]
Conventionally, as this type of membrane module, for example, there is a membrane module in which a ceramic membrane 72 is housed in a cylindrical casing 71 as shown in FIG. A raw water supply port 73 is formed at a lower portion of the casing 71, a rinse water supply port 74 is formed at an upper portion of the casing 71, and a filtered water discharge port 75 is formed at an outer peripheral portion of the casing 71.
[0003]
The raw water supply port 73 is connected to a raw water supply passage 76 for supplying raw water, and a backwash discharge passage 77 branched from the raw water supply passage 76 to discharge backwash wastewater. The raw water supply passage 76 is provided with a raw water supply valve 78, and the backwash discharge passage 77 is provided with a backwash drain valve 79.
[0004]
Further, a rinsing water supply channel 80 for supplying rinsing water is connected to the rinsing water supply port 74. The rinse water supply passage 80 is provided with a rinse water supply valve 81.
[0005]
Further, a filtered water discharge channel 82 for discharging the filtered water is connected to the filtered water discharge port 75. The filtered water discharge channel 82 is provided with a filtered water valve 83 and a pressurized tank 84. The pressurized tank 84 is provided between the filtered water valve 83 and the casing 71, and supplies a high-pressure air supply line 85 for supplying high-pressure air to the pressurized tank 84 and a high-pressure air in the pressurized tank 84 to the outside. A high pressure air discharge line 86 for discharging is provided. The high-pressure air supply line 85 is provided with a high-pressure air supply valve 87, and the high-pressure air discharge line 86 is provided with a pressure release valve 88.
[0006]
According to this, when the amount of deposits on the surface of the ceramic membrane 72 increases while the filtration is continued, backwashing including the following pressing step, opening step, and backwashing step is performed. First, after the filtration is stopped, as a pressurizing step, the high-pressure air supply valve is closed with the raw water supply valve 78, the backwash drain valve 79, the rinse water supply valve 81, the filtered water valve 83, and the pressure release valve 88 closed. Open 87 and add high pressure air into pressurized tank 84. As a result, the inside of the casing 71 is pressurized to a high pressure, and the raw water side and the filtration side of the ceramic membrane 72 are kept at the same pressure.
[0007]
Next, as an opening step, the backwash drain valve 79 is rapidly opened while the high-pressure air supply valve 87 is open, and the pressure on the raw water side is released at a time. As a result, the pressure on the raw water side drops at once, and a large effective membrane differential pressure is generated, so that the deposits are separated from the membrane surface.
[0008]
Thereafter, as a backwashing step, the high-pressure air supply valve 87 is closed to stop pressurizing the filtration side, and the rinse water supply valve 81 is opened to supply rinse water from the rinse water supply port 74 into the casing 71. . As a result, the separated deposits are discharged from the inside of the casing 71 to the backwashing discharge channel 77 together with the rinse water through the raw water supply port 73 (for example, see Patent Document 1).
[0009]
[Patent Document 1]
Japanese Patent No. 2763262
[Problems to be solved by the invention]
However, in the above-mentioned conventional type, since it is necessary to close the high-pressure air supply valve 87 and open the rinse water supply valve 81 at the time of shifting to the backwashing step after opening the backwash drainage valve 79 in the opening step, the valve There is a problem that operation is troublesome. Further, in addition to connecting the raw water supply flow path 76 for supplying raw water and the filtered water discharge flow path 82 for discharging filtered water to the membrane module, for supplying rinse water for back washing. It is necessary to connect the rinsing water supply channel 80, so that there is a problem that the structure of the membrane module becomes complicated.
[0011]
SUMMARY OF THE INVENTION An object of the present invention is to provide a method for backwashing a membrane module which can reduce troublesome valve operations during backwashing and can simplify the structure of the membrane module.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is directed to a filtration operation, in which a fluid to be processed supplied from a supply unit into a casing is filtered by a membrane element in the casing, and then filtered from a discharge unit to the outside of the casing as a filtration fluid. A method for backwashing a discharged membrane module,
The supply section, a supply flow path for supplying the fluid to be treated, and a backwash discharge flow path for discharging the backwash fluid, the discharge section, a discharge flow path for discharging the filtration treatment fluid, A backwash supply flow path for supplying a backwash fluid is connected, a supply valve is provided in the supply flow path, and a backwash discharge valve is provided in the backwash discharge flow path. A drain valve is provided in the path, and the backwash supply flow path is provided with a backwash supply valve and a backwash pressure pump for pressurizing the backwash fluid and supplying the backwash fluid to a discharge unit,
At the time of backwashing, the backwash pressure pump is operated, the supply valve, the discharge valve, and the backwash discharge valve are closed and the backwash supply valve is opened, and the backwash fluid is discharged from the discharge portion. After supplying to the casing and pressurizing the inside of the casing, and then, when the pressure in the casing is increased to a predetermined pressure, by opening the backwash discharge valve, the supply unit side is opened and the inside of the casing is sharply reduced. The pressure is reduced, and in this state, the backwash fluid is supplied into the casing from the discharge portion by the backwash pressure pump to backwash the membrane element, and discharged from the supply portion to the outside of the casing. It is.
[0013]
According to this, at the time of backwashing, the backwash discharge valve is opened, the supply section side is opened, and the pressure inside the casing is rapidly reduced, whereby a differential pressure is generated, and the backwash fluid instantaneously flows through the casing. Since the fluid flows vigorously at a high flow rate, the deposits attached to the film surface are surely separated from the film surface.
[0014]
Thereafter, without performing valve operation, the backwash fluid is continuously supplied as it is into the casing from the discharge portion to backwash the membrane element and is discharged from the supply portion to the outside of the casing. The deposits that have been peeled off from the membrane surface of the element are flushed away by the backwash fluid and reliably discharged to the outside of the casing.
[0015]
As described above, when the backwash discharge valve is opened and the supply unit side is opened, and when the membrane element is subsequently backwashed, no valve operation is required, so that the backwash operation is facilitated.
In addition, at the time of backwashing, the backwashing fluid is supplied from the discharge unit into the casing and discharged from the supply unit. Therefore, in addition to the supply unit and the discharge unit, a conventional rinse water supply unit (rinse water supply port) is provided. ) Does not need to be formed in the membrane module, thus simplifying the structure of the membrane module.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 4, reference numeral 1 denotes a filtration facility provided with an external pressure type membrane module 10, which is configured as follows.
[0017]
That is, as shown in FIG. 1 to FIG. 3, the casing 11 of the membrane module 10 can adopt various shapes, but in the present embodiment, a straight cylindrical shape is exemplified as an example. Both ends of the casing 11 are opened as membrane element loading ports 11a, and have a flange 12 on the outer peripheral edge of the membrane element loading port 11a.
[0018]
The casing 11 is charged with a plurality (two) of membrane elements 24 to be filled therein from each of the membrane element loading ports 11a on both sides, and is covered by a water supply space 11b formed between the membrane elements 24 on both sides. It has a raw water supply port 14 (an example of a supply unit) for supplying treated water (an example of a fluid to be treated), and has a concentrated water discharge port 15 on both sides.
[0019]
The membrane element 24 includes a plurality of membrane tubes 13 for filtering water to be treated and a focusing plate 16. Each of the membrane tubes 13 is made of ceramic, has a thin straight tube with a closed end, and has a tube wall formed only of a film forming material having a large number of micropores. It has a wall thickness of 0.1 to 0.8 mm.
[0020]
These membrane tubes 13 are arranged in parallel at a predetermined interval, and the base ends are inserted and arranged in through holes formed in the focusing plate 16, and the adhesive layer 17 is filled between the base ends of the membrane tubes 13. The focusing plate 16 is fixed to the focusing plate 16 in a watertight manner.
[0021]
The two membrane elements 24 are filled into the inside of the casing 11 from both the membrane element inlets 11a, and the focusing plate 16 is disposed on the flange 12 via the seal member 18 in a watertight manner.
[0022]
At both ends of the casing 11, a hat-shaped (cap-shaped) water collecting member 20 that covers the base opening 13 a of each membrane tube 13 is detachably provided. A flange 21 is provided at an open end of each of the water collecting members 20, and the flange 21 is disposed in a watertight manner on the focusing plate 16 via a sealing material 22, and is fixed together with the focusing plate 16 by fixing bolts and nuts 23. 12 and integrally connected and fixed. As a result, the focusing plate 16 is sandwiched between the flanges 12 and 21, the membrane element 24 is fixed in the casing 11, and the water collecting members 20 are attached to both ends of the casing 11.
[0023]
A filtered water discharge port 25 (an example of a discharge unit) for discharging filtered water (water to be treated filtered by the membrane element 24) to the outside of the membrane module 10 is provided at an upper portion of the outer periphery of the water collecting members 20. A drain outlet 26 for discharging the drain in the water collecting member 20 is provided at a lower portion of the outer periphery of both the water collecting members 20.
[0024]
Next, the configuration of the backwashing device 31 connected to the membrane module 10 will be described.
As shown in FIGS. 1 and 4, the raw water supply port 14 has a supply flow path 32 (pipe) for supplying the water to be treated into the membrane module 10, and a backwash water ( An example of a backwash fluid) is connected to a backwash discharge channel 33 (piping) for discharging the backwash fluid to a drainage tank 39 outside the membrane module 10.
[0025]
In addition, the two filtered water discharge ports 25 are provided with a discharge flow path (pipe) for discharging the filtered water to a processing water tank 40 outside the membrane module 10, and merged with the discharge flow path 34 to supply backwash water to the membrane. The backwash supply flow path 35 (pipe) to be supplied into the module 10 is connected.
[0026]
The supply flow path 32 is provided with a supply pump 36 for pressure-feeding the water to be treated to the raw water supply port 14 and a supply valve 37 for opening and closing the supply flow path 32. The supply valve 37 is provided on the discharge side of the supply pump 36.
[0027]
The backwash discharge passage 33 is provided with a backwash discharge valve 41 for opening and closing the backwash discharge passage 33. The downstream end of the backwashing discharge channel 33 is open to the atmosphere. Further, as the backwash discharge valve 41, a butterfly valve or the like capable of opening (closing) a valve body quickly (quickly) is used.
[0028]
The discharge passage 34 is provided with a discharge valve 42 for opening and closing the discharge passage 34.
The backwashing supply channel 35 includes a backwashing pressure pump 43 that pressurizes the filtered water in the treated water tank 40 as backwashing water and supplies the backwashed water to the two filtrated water outlets 25; A backwash supply valve 44 for opening and closing the supply passage 35 is provided. The backwash supply valve 44 is provided on the discharge side of the backwash pressure pump 43.
[0029]
The concentrated water discharge port 15 is provided with a concentrated water discharge flow path (not shown) and a concentrated water discharge valve (not shown) for opening and closing this flow path. A discharge flow path (not shown) and a drain discharge valve (not shown) for opening and closing this flow path are provided. The casing 11 is provided with a pressure gauge (not shown) for detecting the pressure inside the casing 11.
[0030]
Hereinafter, the operation of the above configuration will be described.
When the filtration operation is performed, the supply valve 37 and the discharge valve 42 are both set to “open”, and the backwash discharge valve 41 and the backwash supply valve, as shown in the water passage process of the valve opening / closing table in FIG. 44 are both closed. Thereby, the supply flow path 32 and the discharge flow path 34 are opened, the backwash discharge flow path 33 and the backwash supply flow path 35 are closed, and the water to be treated is pumped by the operation of the supply pump 36. Is supplied from the raw water supply port 14 to the inside of the casing 11 through the supply flow path 32, and is filtered from the outside to the inside of each of the membrane tubes 13, and then filtered as the filtered water. The water flows into the water collecting member 20 through the base opening 13a through the base 13b, and is discharged from both the filtered water discharge ports 25 through the discharge flow path 34 to the treated water tank 40.
[0031]
Next, a method for performing backwashing will be described.
First, the supply pump 36 is stopped, and all the valves 37, 41, 42, and 44 are set to "closed" and the respective flow paths 32, 33, 34, and 35 are closed as shown in the stop process of the valve opening / closing table in FIG. Close and stop the supply of the water to be treated to the membrane module 10. Next, as shown in the pressurizing step of the valve opening / closing table in FIG. 5, the backwashing supply valve 35 is opened to open the backwashing supply channel 35 and the backwashing pressure pump 43 is operated. As a result, the filtered water in the treated water tank 40 is pressurized as backwash water (an example of a backwash fluid), passes through the backwash supply flow path 35, passes through both the filtrate outlets 25, and is discharged from the casing 11. It is supplied inside and the inside of the casing 11 is pressurized.
[0032]
Then, when the pressure in the casing 11 is increased to a predetermined pressure (for example, about 500 kPa), the backwash discharge valve 41 is set to “open” as shown in “opening + backwashing step” of the valve opening / closing table in FIG. By suddenly opening the backwash discharge passage 33, the raw water supply port 14 side is opened to the atmosphere at once, and the pressure inside the casing 11 is rapidly reduced. As a result, a differential pressure is generated, and the backwash water instantaneously and vigorously flows at a high flow rate from the inside to the outside of each of the membrane tubes 13. ) Is surely peeled off from the outer peripheral surface of each membrane tube 13. In addition, since the membrane tubes 13 are uniformly exposed to the backwashing action by rapidly releasing the air from the pressurized state to the atmosphere as described above, the backwashing effect can be homogenized. Variations (differences) in the backwashing effect are reduced.
[0033]
Thereafter, the filtered water in the treated water tank 40 is continuously collected as it is through the backwashing supply channel 35 as backwashing water without any valve operation. After being supplied to the inside of the member 20 and flowing into the internal flow path 13b from the base end opening 13a of each membrane tube 13 and permeating from the inside to the outside of each membrane tube 13 to backwash each membrane tube 13, the raw water supply port From 14, the water is continuously discharged to the drainage tank 39 through the backwashing discharge channel 33. Thereby, the adhered substances peeled off from the outer peripheral surface of each membrane tube 13 are washed away by the backwash water and reliably discharged to the outside of the casing 11.
[0034]
As described above, in the opening + backwashing step, when the backwash discharge valve 41 is opened to open the raw water supply port 14 to the atmosphere and subsequently the membrane tube 13 is backwashed, no valve operation is required. Backwashing work becomes easy.
[0035]
In addition, at the time of backwashing, the backwash water is supplied into the casing 11 from both filtered water discharge ports 25 and discharged from the raw water supply port 14, so that in addition to the above-mentioned raw water supply port 14 and the filtered water discharge port 25, the conventional water is used. It is not necessary to form such a rinse water supply port 74 (see FIG. 7) in the membrane module 10, and therefore, the structure of the membrane module 10 is simplified.
[0036]
When the filtration operation is performed again after the opening and backwashing step, the backwashing pressure pump 43 is stopped, and all the valves 37 and 41 are stopped as shown in the stopping step of the valve opening / closing table in FIG. , 42, 44 are once closed, the respective flow paths 32, 33, 34, 35 are closed, and the supply of backwash water to the membrane module 10 is stopped.
[0037]
Thereafter, the supply pump 36 is operated, and the supply valve 37 and the discharge valve 42 are both opened, as shown in the water passage step of the valve opening / closing table in FIG. The washing supply valve 44 is kept "closed". Thereby, the supply flow path 32 and the discharge flow path 34 are opened, the backwash discharge flow path 33 and the backwash supply flow path 35 are closed, and the water to be treated flows from the raw water supply port 14 into the casing 11. , And is filtered, and is discharged from both filtered water discharge ports 25 to the treated water tank 40 as filtered water.
[0038]
In the above-described first embodiment, as shown in FIG. 1, the external pressure type membrane module 10 that permeates and filters the water to be treated from the outside to the inside of the membrane tube 13 during the filtration operation is described. As shown in FIG. 6, an embodiment using an internal pressure type membrane module 50 for permeating and filtering water to be treated from the inside to the outside of the membrane tube 13 during the filtration operation will be described below.
[0039]
That is, in the internal pressure type membrane module 50, the water distribution members 51 having the same shape as the water collecting members 20 (see FIG. 1) are provided at both ends of the casing 11, and the base end openings 13 a of the respective membrane tubes 13 are formed as described above. It is covered by the water distribution member 51.
[0040]
Further, a raw water supply port 14 is provided at a lower part of the outer periphery of both water distribution members 51, a filtered water discharge port 25 is provided at an upper part of the casing 11, a drain discharge port 26 is provided at a lower part of the casing 11, and an air vent 52 Are provided on the upper outer periphery of both water distribution members 51.
[0041]
The raw water supply ports 14 are connected to a supply channel 32 and a backwash discharge channel 33 branched from the supply channel 32. Further, a drain passage 34 and a backwashing supply passage 35 joined to the drain passage 34 are connected to the filtered water outlet 25.
[0042]
As shown in FIG. 4, a supply pump 36 and a supply valve 37 are provided in the supply flow path 32. Further, a backwash discharge valve 41 is provided in the backwash discharge channel 33. Further, a discharge valve 42 is provided in the discharge passage 34. The backwashing supply flow path 35 is provided with a backwashing pressure pump 43 and a backwashing supply valve 44.
[0043]
The drain discharge port 26 is provided with a drain discharge flow path (not shown) and a drain discharge valve (not shown) for opening and closing the flow path. An air vent channel (not shown) and an air vent valve (not shown) for opening and closing this channel are provided.
[0044]
Hereinafter, the operation of the above configuration will be described.
When the filtration operation is performed, the supply valve 37 and the discharge valve 42 are both set to “open”, and the backwash discharge valve 41 and the backwash supply valve, as shown in the water passage process of the valve opening / closing table in FIG. 44 are both closed. As a result, the water to be treated is supplied from the raw water supply ports 14 to the insides of the water distribution members 51 through the supply flow paths 32, flows into the internal flow paths 13b from the base end openings 13a of the respective membrane tubes 13, and flows through the respective membranes. After being filtered from the inside to the outside of the tube 13 and filtered, the filtered water is discharged from the filtered water discharge port 25 through the discharge flow path 34 to the treated water tank 40.
[0045]
Next, a method for performing backwashing will be described.
First, the supply pump 36 is stopped, and all the valves 37, 41, 42, and 44 are set to "closed" and the respective flow paths 32, 33, 34, and 35 are closed as shown in the stop process of the valve opening / closing table in FIG. Close and stop the supply of the water to be treated to the membrane module 50. Next, as shown in the pressurizing step of the valve opening / closing table in FIG. 5, the backwashing supply valve 35 is opened to open the backwashing supply channel 35 and the backwashing pressure pump 43 is operated. As a result, the filtered water in the treated water tank 40 is pressurized as backwashing water, passes through the backwashing supply channel 35, is supplied from the filtered water discharge port 25 to the inside of the casing 11, and Is pressurized.
[0046]
Then, when the pressure in the casing 11 is increased to a predetermined pressure (for example, about 500 kPa), the backwash discharge valve 41 is set to “open” as shown in “opening + backwashing step” of the valve opening / closing table in FIG. By suddenly opening the discharge channel 33 for backwashing, the raw water supply ports 14 are opened to the atmosphere at once, and the pressure inside the casing 11 is rapidly reduced. As a result, a differential pressure is generated, and the backwash water instantaneously and vigorously flows at a high flow rate from the outside to the inside of each membrane tube 13. The substance) is surely peeled off from the inner peripheral surface of each membrane tube 13. In addition, since the membrane tubes 13 are uniformly exposed to the backwashing action by rapidly releasing the air from the pressurized state to the atmosphere as described above, the backwashing effect can be homogenized. Variations (differences) in the backwashing effect are reduced.
[0047]
Thereafter, the filtered water in the treated water tank 40 is continuously passed through the backwashing supply flow path 35 as backwashing water without passing through the valve, and the filtered water in the casing 11 is passed through the filtered water discharge port 25. After being permeated from the outside to the inside of each membrane tube 13 to backwash each membrane tube 13, flows through the internal channel 13 b of each membrane tube 13, and flows out from the base end opening 13 a to the inside of the water distribution member 51. Then, the raw water is continuously discharged from the raw water supply ports 14 to the drainage tank 39 through the discharge channel 33 for backwashing.
[0048]
Thereby, the adhered substances peeled off from the inner peripheral surface of each membrane tube 13 are washed away by the backwash water and reliably discharged to the outside of the casing 11.
As described above, in the opening and backwashing process, when the backwash discharge valve 41 is opened to open both raw water supply ports 14 to the atmosphere and subsequently the membrane tube 13 is backwashed, no valve operation is required. This facilitates backwashing.
[0049]
In addition, at the time of backwashing, backwash water is supplied into the casing 11 from the filtered water discharge port 25 and discharged from both raw water supply ports 14, so that in addition to the raw water supply port 14 and the filtered water discharge port 25, a conventional It is not necessary to form such a rinse water supply port 74 (see FIG. 7) in the membrane module 50, and therefore, the structure of the membrane module 50 is simplified.
[0050]
When the filtration operation is performed again after the opening and backwashing step, the backwashing pressure pump 43 is stopped, and all the valves 37 and 41 are stopped as shown in the stopping step of the valve opening / closing table in FIG. , 42, and 44 are once closed, and the flow paths 32, 33, 34, and 35 are closed to stop supplying the backwash water to the membrane module 10.
[0051]
Thereafter, the supply pump 36 is operated, and the supply valve 37 and the discharge valve 42 are both opened, as shown in the water passage step of the valve opening / closing table in FIG. The washing supply valve 44 is kept "closed". As a result, the supply flow path 32 and the discharge flow path 34 are opened, the backwash discharge flow path 33 and the backwash supply flow path 35 are closed, and the water to be treated flows from the raw water supply ports 14 through the casing 11. The water is supplied to the inside and filtered, and is discharged from the filtered water discharge port 25 to the treated water tank 40 as filtered water.
[0052]
In each of the above embodiments, the membrane element 24 has a structure in which the plurality of membrane tubes 13 are focused by the focusing plate 16. However, the invention is not limited to this structure, and the longitudinal direction of the cylindrical porous body is not limited thereto. May have a monolith structure (multi-lumen structure) having a plurality of parallel flow paths, or a honeycomb structure.
[0053]
Also, the material of the membrane tube 13 has been described by taking a ceramic material as an example. However, the material is not limited to the ceramic material, and may be an organic material such as cellulose acetate or polyvinylidene fluoride. Is also good.
[0054]
【The invention's effect】
As described above, according to the present invention, after pressurizing the inside of the casing, opening the backwash discharge valve and opening the supply unit side, and subsequently backwashing the membrane element, no valve operation is necessary, Backwashing work becomes easy. In addition, it is not necessary to form a rinse water supply section (rinse water supply port) in the membrane module in addition to the supply section and the discharge section, so that the structure of the membrane module is simplified.
[Brief description of the drawings]
FIG. 1 is a sectional view of a membrane module according to a first embodiment of the present invention.
FIG. 2 is a sectional view of a membrane element of the membrane module.
FIG. 3 is a view taken along the line XX in FIG. 2;
FIG. 4 is a schematic diagram showing a configuration of a backwashing device for the membrane module.
FIG. 5 is a chart showing opening and closing operations of each valve of the backwashing device for the membrane module.
FIG. 6 is a sectional view of a membrane module according to a second embodiment of the present invention.
FIG. 7 is a diagram of a conventional membrane module.
[Explanation of symbols]
10,50 membrane module 11 casing 14 raw water supply port (supply section)
24 Membrane element 25 Filtration water outlet (discharge part)
32 supply flow path 33 backwash discharge flow path 34 discharge flow path 35 backwash supply flow path 37 supply valve 41 backwash discharge valve 42 discharge valve 43 backwash pressure pump 44 backwash supply valve

Claims (1)

In the filtration operation, a backwashing method of a membrane module is provided in which a fluid to be treated supplied from a supply unit into a casing is filtered by a membrane element in the casing, and then discharged from a discharge unit to the outside of the casing as a filtration treatment fluid. hand,
The supply section, a supply flow path for supplying the fluid to be treated, and a backwash discharge flow path for discharging the backwash fluid, the discharge section, a discharge flow path for discharging the filtration treatment fluid, A backwash supply flow path for supplying a backwash fluid is connected, a supply valve is provided in the supply flow path, and a backwash discharge valve is provided in the backwash discharge flow path. A drain valve is provided in the path, and the backwash supply flow path is provided with a backwash supply valve and a backwash pressure pump for pressurizing the backwash fluid and supplying the backwash fluid to a discharge unit,
At the time of backwashing, the backwash pressure pump is operated, the supply valve, the discharge valve, and the backwash discharge valve are closed and the backwash supply valve is opened, and the backwash fluid is discharged from the discharge portion. After supplying to the casing and pressurizing the inside of the casing, and then, when the pressure in the casing is increased to a predetermined pressure, by opening the backwash discharge valve, the supply unit side is opened and the inside of the casing is sharply reduced. The pressure is reduced, and in this state, the backwashing fluid is supplied into the casing from the discharge portion by the backwashing pressure pump to backwash the membrane element, and is discharged from the supply portion to the outside of the casing. Backwashing method of a membrane module characterized by the above-mentioned.

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