KR101568041B1 - System for Filtering - Google Patents

Abstract

The present invention is capable of performing filtration work at a high recovery rate of 96% or more, and also can prevent the concentration of fouling in any one of the filtration membrane cassettes immersed in a water tank, The present invention relates to a filtration system, comprising: a feed water tank for storing raw water to be treated; A water bath having a first opening and a second opening; A switching unit for selectively communicating the raw water tank with any one of the first and second openings so that raw water stored in the raw water tank flows into the water tank; And a plurality of filter film cassettes immersed in the raw water introduced into the water tank.

Filtration, filtration membrane, cassette, water tank

Description

System for Filtering

The present invention relates to a filtration system, and more particularly, to a filtration system capable of performing a filtration operation at a high recovery rate of 96% or more, as well as fouling of a filtration membrane of any of the filtration membrane cassettes immersed in a water tank To a filtration system capable of increasing the recovery cleaning cycle by preventing concentration.

Compared with the separation method using heating or phase change, the separation method using the filter membrane has many advantages. One of them is that a desired quality of water can be stably obtained by using a filtration membrane having an appropriate pore size, thereby improving the reliability of the process. Further, since the filtration membrane does not require any operation such as heating, it can be used in a separation process using a microorganism that can be influenced by heating or the like.

One of the separation methods using a filtration membrane is a method using a hollow fiber membrane module including a hollow fiber membrane bundle and a method using a flat membrane module. Traditionally, filtration membrane modules have been widely used in the fields of aseptic water, drinking water, and ultrapure water, and recently in sewage treatment, solid-liquid separation in septic tanks, removal of suspended solids (SS) in industrial wastewater, , Filtration of industrial water, and filtration of storage facilities.

One of such filtration membrane modules is a submerged membrane membrane membrane membrane membrane membrane membrane membrane module which immerses a filtration membrane module directly in a tank of a fluid to be treated and separates solid components such as impurities or sludge by selectively applying a negative pressure to the inside of the filtration membrane, There is a filter membrane module. The submersible filter membrane module is mainly used as a cassette unit in which a plurality of modules are mounted on a frame.

More specifically, as shown in FIG. 1, raw water is supplied to the water tank 10 from a raw water tank 20 storing raw water to be processed. A plurality of filter film cassettes 11 are immersed in a water bath 10. When a certain negative pressure is applied to the plurality of filter film cassettes 11 by the suction pump 30, only the fluid excluding the solid component selectively passes through the filter film in the filter film cassettes 11. [ The fluid (hereinafter referred to as "filtered water") that has passed through the filtration membrane is sent to a filtrate tank (not shown).

On the other hand, since the plurality of filter film cassettes 11 are sufficiently spaced from each other in the water tank 10, raw water flowing into the water tank 10 is uniformly dispersed in each of the filter film cassettes 11, When the equilibrium state is established, each of the filter film cassettes 11 treats raw water containing impurities at almost the same concentration.

However, since each of the filtration film cassettes 11 has a recovery rate of about 90% which means a ratio of the amount of filtered water treated by the cassette to the amount of raw water supplied to the cassette, the filtration system shown in FIG. The total recovery rate is only about 90%. That is, the residue discharged from the water tank 10 after being treated by the plurality of filter film cassettes 11 contains a considerable amount of water which is in a state of slurry containing a large amount of solid components, but which is still untreated.

A concentrating device 40 for recovering the water not collected by the filter film cassettes 11 in the water tank 10 may be additionally provided. However, since the concentrating device 40 mainly uses a rough filtration method such as a fabric filter or a sandblast method, the recovered water is separated from the filtered water obtained by the filter film cassettes 11 It can not be handled in the same way. Therefore, water additionally obtained from the concentration apparatus 40 is supplied to the raw water tank 20, and does not contribute to increasing the overall recovery rate of the filtration system.

As a result, the filtration system shown in FIG. 1 has a problem that the total recovery rate is only about 90%, which is uneconomical.

Accordingly, the present invention is directed to a filtration system that can avoid problems due to limitations and disadvantages of the related art.

The advantage of the present invention is that filtration can be performed at a high recovery rate of 96% or more, as well as the concentration of fouling is prevented from concentrating on one of the filter film cassettes immersed in the water tank, And to provide a filtration system capable of increasing the filtration efficiency.

Further features and advantages of the invention will be described hereinafter, and will in part be obvious from the description. Alternatively, other features and advantages of the invention may be learned through practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS The objects and other advantages of the present invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these and other objects and in accordance with the purpose of the present invention, a feed water tank for storing raw water to be treated; A water bath having a first opening and a second opening; A switching unit for selectively communicating the raw water tank with any one of the first and second openings so that raw water stored in the raw water tank flows into the water tank; And a plurality of filter film cassettes immersed in the raw water introduced into the water tank.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the invention as claimed.

According to the filtration system of the present invention, the structure of the entire filtration system can be compact and simplified, and the waste water can be treated at a high recovery rate of 96% or more.

In addition, by constantly changing the flow direction of the raw water in the water tank, the fouling can be prevented from concentrating on any one of the filter film cassettes immersed in the water tank, and as a result, the recovery cleaning cycle of the filter film cassettes can be increased .

In addition, despite the impurity concentration gradient in the water tank due to the compact structure, the equalization of the load on each filter cassette can be prevented, thereby preventing the filter membrane from being damaged due to overload.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Therefore, the present invention encompasses all changes and modifications that come within the scope of the invention as defined in the appended claims and equivalents thereof.

As used herein, the term 'filtration membrane' includes both immersion type membranes such as a flat sheet membrane and a hollow fiber membrane.

As used herein, the term " impurity " includes all the solid components contained in water.

As used herein, the term " concentration of impurities " refers to the concentration of impurities measured when the water treatment process reaches an equilibrium state, and is measured at least 24 hours after the start of the water treatment operation.

Hereinafter, one embodiment of the filtration system and method of the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic view of a filtration system according to a first embodiment of the present invention.

As shown in FIG. 2, raw water is supplied to the water tank 100 from a raw water tank 200 storing raw water to be processed. The water tank 100 is provided with a first opening 101 and a second opening 102 so that the water tank 100 can receive the raw water and discharge the concentrated raw water after the treatment. The concentrated raw water is sent to the sludge storage tank (not shown) via the concentration device 300. The concentrator 300 is for recovering water additionally, and includes a fabric filter or a sandblast system.

Meanwhile, since the filtration system of the present invention treats the waste water at a high recovery rate of 96% or more, concentrated raw water treated in the water tank 100 may be sent to the sludge storage tank without passing through the concentration apparatus 300. In this case, reference numeral 300 should be understood to mean a sludge storage tank.

A plurality of filter film cassettes 111 to 117 for performing a filtering function are immersed in the raw water in the water tank 100. According to the present invention, the plurality of filter film cassettes 111 to 117 are arranged in a line from the first opening 101 side to the second opening 102 side. In addition, the plurality of filter film cassettes 111 to 117 are densely packed in the water tub 100. Therefore, raw water flowing into the water tub 100 can not be dispersed substantially simultaneously in the respective filter membrane cassettes 111 to 117, and sequentially passes through the filter membrane cassettes 111 to 117 arranged in a row.

For example, the raw water introduced through the first opening 101 is first treated by the filter film cassette 111 located closest to the first opening 101, Then moved to the next filtration cassette 112 and processed secondarily. The secondary treated raw water is then finally treated by the filter membrane cassettes 117, which are located in the closest position to the second opening 102 after being sequentially treated through the filter membrane cassettes 113 to 116 in turn. Therefore, when the water treatment process is in an equilibrium state, a gradient of the impurity concentration is generated in the raw water in the water tank 100 according to the position. As a result, a filter film cassette 111 is smaller than the impurity concentration of the raw water to be treated by the filtration film cassette 117 located nearest to the second opening 102.

That is, according to one embodiment of the present invention, the filtration film cassette 111 positioned closest to the first opening 101 and the filtration film cassette 117 positioned closest to the second opening 102, The plurality of filter film cassettes 111 to 117 are densely packed in the water tank 100 so that the difference in the impurity concentration of the raw water to be treated is at least tripled.

The impurity concentration of the raw water treated by the filter film cassettes 111 to 117 means the concentration of impurities measured by taking water located at a certain height in a space within 20 cm on each side of each of the filter film cassettes 111 to 117. Taking the water at the predetermined height means that water having the same height is taken to measure the impurity concentration of the raw water to be treated by the filter film cassettes 111 to 117.

As described above, according to the filtration system of the present invention, since the raw water introduced into the water tank 100 is repeatedly processed while sequentially passing through a plurality of filter film cassettes 111 to 117, The effluent is in a highly concentrated slurry state. That is, the filtration system according to the present invention has a total recovery of 96% or more.

On the other hand, in the filtration system according to the present invention, since the impurity concentrations of the raw water to be treated by the filtration cassettes 111 to 117 are different from each other, when the same negative pressure is applied to each of the filtration cassettes 111 to 117, Will appear differently for each of the cassettes 111-117. That is, the filtration membrane of the filter membrane cassette having the highest impurity concentration (the most concentrated) should be subjected to the greatest load, and in severe cases, the filtration membrane may be damaged due to overload.

Therefore, when the raw water from the raw water tank 200 flows into the water tank 100 through the first opening 101, the first negative pressure is applied to the filter film cassettes 111 to 116 from the first pump 120 And the second negative pressure is applied to the filtration film cassette 117 closest to the second opening 102 by the second pump 140. As a result, So that it can be released at the second permeate flow rate. Naturally, the first negative pressure and the first permeate flow rate are larger than the second negative pressure and the second permeate flow rate. As described above, by applying a lower sound pressure to the filter film cassette 117 which needs to treat the raw water having the highest impurity concentration (the most concentrated), it is possible to minimize the damage of the filter membrane due to the overload.

According to the first embodiment of the present invention, the first pump 120 for providing the first negative pressure is connected to each of the filter film cassettes 111 to 117 by turning on / off the first pump valves 130, And a second pump 140 providing a second negative pressure lower than the first negative pressure may be connected to each of the filter film cassettes 111 through 117 by turning on and off the second pump valves 150 have.

Therefore, when the raw water from the raw water tank 200 flows into the water tank 100 through the first opening 101, the first pump valves 131 to 136 are turned on and the second pump valve The first and second filter valves 151 to 156 are turned off so that the filter cassettes 111 to 116 are supplied with the first negative pressure from the first pump 120 and the first pump valve 137 is turned off, The valve 157 is turned on and the filter film cassette 117 positioned closest to the second opening 102 receives the second negative pressure from the second pump 140.

On the contrary, when the raw water from the raw water tank 200 flows into the water tank 100 through the second opening 102, the first pump valves 132 to 137 are turned on and the second pump valve The filter media cassettes 112 to 117 are supplied with the first negative pressure from the first pump 120 and the first pump valve 131 is turned off, The valve 151 is turned on and the filter film cassette 111 located closest to the first opening 101 receives the second negative pressure from the second pump 140. In some cases, the first and second pump valves 132 and 152 may be appropriately adjusted so that the filtration membrane cassette 112 can also receive the second negative pressure from the second pump 140 .

Hereinafter, the change of the path of the raw water from the raw water tank 200 into the water tank 100 will be described in detail.

In the filtration system according to the present invention, since the impurity concentrations of the raw water to be treated by the filtration cassettes 111 to 117 are different from each other, the fouling degree of the filtration membrane is controlled by the cassettes 111 to 117 Appear differently. That is, the fouling of the most severe filtration film occurs in the filter cassette where the raw water having the highest impurity concentration (the most concentrated) has to be treated. For example, if the raw water flows into the water tank 100 only through the first opening 101, the second opening 102 will function only as the discharge passage of the concentrated raw water after the water treatment, The most serious fouling will occur in the filtration membrane of the filtration membrane cassette 117 located closest to the inlet of the filtration membrane cassette.

As the fouling or fouling of the filtration membrane becomes more serious, the cycle of the recovery cleaning requiring the shutdown of the system becomes shorter. The recovery washing is a cleaning process which is stopped for a long period of time by stopping the water treatment when the filtration performance of the filtration membrane is seriously degraded due to accumulation of contamination of the filtration membrane due to the progress of the water treatment for a long time, and chemical chemicals are used and the permeation performance of the filtration membrane is recovered There is a main purpose. When the cycle of recovery washing is short, the cost increases as the number of recovery tax increases, and the water treatment efficiency decreases as the number of times of shutdown increases.

The filtration system of the present invention is characterized in that the raw water tank 200 is connected to any one of the first and second openings 101 and 102 of the water tank 100 to transmit the raw water stored in the raw water tank 200 to the water tank 100 The fouling can be prevented from concentrating on one of the filter film cassettes 111 to 117 immersed in the water tub 100. [ The switching unit 400 selectively connects the concentrator 300 to any one of the first and second openings 101 and 102 to transfer the raw water discharged from the water tank 100 to the concentrator 300. [ .

According to the first embodiment of the present invention shown in FIG. 2, the switching unit 400 includes a first valve 410, a raw water tank 200 and a second valve 410 between the raw water tank 200 and the first opening 101, A second valve 420 between the openings 102, a third valve 430 between the concentrator 300 and the first opening 101 and a second valve 430 between the concentrator 300 and the second opening 102. 4 < / RTI >

When the first valve 410 and the fourth valve 440 are turned on, the raw water in the raw water tank 200 flows into the water tub 100 through the first opening 101 to be supplied to the filter film cassettes 111 to 117, And then sent to the concentration apparatus 300 through the second opening 102. [ At this time, the second valve 420 and the third valve 430 are turned off. The filtration film cassettes 111 to 116 are supplied with the first negative pressure from the first pump 120 and the filtration film cassettes 117 positioned closest to the second opening 102 are supplied from the second pump 140 2 Sound pressure is provided.

On the other hand, when the second valve 420 and the third valve 430 are turned on, the raw water of the raw water tank 200 flows into the water tub 100 through the second opening 102, 117 and then to the concentrator 300 through the first opening 101. [ At this time, the first valve 410 and the fourth valve 440 are turned off. The filtration film cassettes 112 to 117 are supplied with the first negative pressure from the first pump 120 and the filtration film cassettes 111 positioned closest to the first opening 101 are supplied from the second pump 140 2 Sound pressure is provided.

3 is a schematic view of a filtration system according to a second embodiment of the present invention.

According to the second embodiment of the present invention, the switching unit 400 of the present invention includes the first opening 101 for selectively communicating with either the raw water tank 200 or the concentrating apparatus 300, A port valve 450 and a second 3-port valve 460 for selectively communicating the second opening 102 with either the raw water tank 200 or the concentration device 300.

According to the second embodiment of the present invention, only the filter film cassettes 111 and 117 positioned closest to the first and second openings 101 and 102 respectively correspond to the first pump valves 131 and 137, The filter film cassettes 112 to 116 located between the filter film cassettes 111 and 117 can be selectively connected to the first and second pumps 120 and 140 through the two pump valves 151 and 157, Only the first pump 120 is connected.

When the raw water tank 200 and the first opening 101 are communicated with each other by the first 3-port valve 450, the concentration device 300 and the second opening 102 are separated by the second 3- . At this time, the first pump valve 131 is turned on and the second pump valve 151 is turned off, so that the filter film cassette 111 is connected to the first pump 120, Receive. The first pump valve 137 is turned off and the second pump valve 157 is turned on so that the filtration membrane cassette 117 is connected to the second pump 140 so as to be lower than the first sound pressure And receives a second negative pressure. The remaining filter cassettes 112 to 116 are supplied with the first negative pressure from the first pump 120.

Conversely, when the concentrating device 300 and the first opening 101 are communicated by the first 3-port valve 450, the raw water tank 200 and the second opening 102 . At this time, the first pump valve 131 is turned off and the second pump valve 151 is turned on so that the filtration membrane cassette 111 is connected to the second pump 140 to provide the second negative pressure Receive. The first pump valve 137 is turned on and the second pump valve 157 is turned off so that the filtration membrane cassette 117 is connected to the first pump 120 to provide the first negative pressure Receive. The remaining filter cassettes 112 to 116 are also supplied with the first negative pressure from the first pump 120.

4 is a block diagram schematically illustrating a control system according to an embodiment of the present invention.

As shown in FIG. 4, the filtering system according to an embodiment of the present invention further includes a control unit 500 for controlling the overall operation of the system.

The controller 500 controls the on / off states of the first pump valves 130 and the second pump valves 150 to adjust the magnitude of the sound pressure provided to each of the filter cassettes 111 to 117 . In addition, the control unit 500 can continuously change the flow direction of the raw water in the water tank by controlling the switching unit 400. [

The control unit 500 can change the flow direction of the raw water in the water tank at regular intervals. For example, in the first embodiment of the present invention shown in FIG. 2, the controller 500 may alternately turn on the first and second valves 410 and 420 at regular intervals. In this case, the third valve 430 is turned off when the first valve 410 is turned on and the fourth valve 440 is turned off when the second valve 420 is turned on. (off).

Alternatively, the control unit 500 of the present invention may change the flow direction of the raw water based on the contamination degree of the filtration film. To this end, the filtration system of the present invention may further include a membrane contamination detection unit 600. The degree of contamination of the filtration membrane can be obtained, for example, by measuring the Trans Membrane Pressure (TMP).

The membrane contamination detecting unit 600 detects the degree of contamination of the filter membranes 111 and 117 located closest to the first and second openings 101 and 102 and transmits the contamination data to the controller 500 . The control unit 500 controls the switching unit 400 based on the contamination data.

For example, in the first embodiment of the present invention shown in FIG. 2, when the first valve 410 is turned on and the second valve 420 is turned off, The degree of fouling of the filtration membrane of the filtration film cassette 117 closest to the filtration membrane cassette 117 is continuously detected by the membrane fouling sensing unit 600 and reported to the controller 500. The control unit 500 changes the flow direction of the raw water by turning off the first valve 410 and turning on the second valve 420 when the degree of contamination of the filtration film increases by a certain amount. The controller 500 monitors the degree of contamination of the filter membrane cassette 111 located closest to the first opening 101. When the degree of contamination increases by a predetermined magnitude, the first valve 410 is turned on and the flow direction of the raw water is changed again by turning off the second valve 420.

Such continuous change in the raw water flow direction prevents fouling from concentrating in any one of the filtration film cassettes 111 to 117 immersed in the water tank 100, and as a result, the recovery cleaning cycle of the filtration film can be increased .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

Figure 1 is a schematic representation of a general filtration system,

2 and 3 are schematic views respectively showing filtration systems of the first and second embodiments of the present invention,

4 is a block diagram schematically illustrating a control system according to an embodiment of the present invention.

Claims (13)

A feed water tank for storing raw water to be treated; A water bath having a first opening and a second opening; A switching unit for selectively communicating the raw water tank with any one of the first and second openings so that raw water stored in the raw water tank flows into the water tank; A plurality of filter film cassettes immersed in the raw water introduced into the water tank; A first pump for providing a first negative pressure; And And a second pump for providing a second negative pressure smaller than the first negative pressure, Wherein each of the plurality of filter cassettes receives a negative pressure from any one of the first and second pumps. The method according to claim 1, Wherein when the raw water tank is communicated with the opening of any one of the first and second openings by the switching unit, the raw water is discharged out of the water tank through the other opening. The apparatus of claim 1, A first valve between the raw water tank and the first opening; And And a second valve between the raw water tank and the second opening. The method of claim 3, Further comprising a controller for controlling on / off of the first and second valves. 5. The method of claim 4, Wherein the control unit alternately turns on the first and second valves at regular intervals. 5. The method of claim 4, Wherein the plurality of filter cassettes include a first filtration film cassette located closest to the first opening and a second filtration film cassette located closest to the second opening, Wherein the filtration system further comprises a membrane fouling sensing unit for sensing a degree of fouling of the filtration membrane of the first and second filtration membrane cassettes, Wherein the control unit controls on / off of the first and second valves based on contamination data transmitted from the membrane contamination detection unit. The method of claim 3, Further comprising a concentration device for collecting additional water from the raw water discharged from the water tank. 8. The method of claim 7, Wherein the switching unit selectively communicates the enrichment apparatus with any one of the first and second openings so that raw water discharged from the water tank is introduced into the enrichment apparatus. 9. The apparatus according to claim 8, A third valve between the condensing device and the first opening; And Further comprising a fourth valve between the concentrating device and the second opening. The method according to claim 1, Further comprising a concentration device for additionally recovering water from the raw water discharged from the water tank, The switching unit includes: A first 3-port valve for selectively communicating the first opening with either the raw water tank or the concentration device; And And a second 3-port valve for selectively communicating the second opening with either the raw water tank or the concentration device. 11. The method of claim 10, And the second opening communicates with the other when the first opening is in communication with the raw water tank and the concentrating device. delete The method according to claim 1, Wherein the plurality of filter cassettes include a first filtration film cassette located closest to the first opening and a second filtration film cassette located closest to the second opening, Wherein when the first opening communicates with the raw water tank, the first filtration film cassette receives a first negative pressure from the first pump, the second filtration film cassette receives the second negative pressure from the second pump, Wherein when the second opening communicates with the raw water tank, the first filtration film cassette receives a second negative pressure from the second pump, and the second filtration film cassette receives the first negative pressure from the first pump Features a filtration system.

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