KR20100032942A - Apparatus and method for filitering using positive pressure - Google Patents

Abstract

PURPOSE: An apparatus for filtering raw water with pressure and a method thereof are provided to effectively prevent the contamination of a filtration membrane and to maximize the effectiveness of water treatment by minimizing a water treatment time delay. CONSTITUTION: An apparatus for filtering raw water with pressure comprises the following: a filtration membrane module including a filtration membrane; a raw water supply member(300) supplying raw water to the filtration membrane module; and an air supply member(400) supplying air to the raw water. A pressurizing filtration method includes a step for supplying the raw water to be processed into a pressurizing filtration membrane and a step for supplying air to the raw water.

Description

Pressurized filtration apparatus and method {Apparatus and Method for Filitering Using Positive Pressure}

The present invention relates to a pressurized filtration device and a method thereof, and more particularly, to a pressurized filtration device and a method capable of performing an acid cleaning of the filtration membrane during the filtration operation.

The separation method using the filtration membrane has many advantages over the separation method using the heating or phase change. One of the biggest advantages is that the desired water quality can be stably obtained according to the pore size of the filtration membrane, thereby increasing the reliability of the process. to be. In addition, since the use of the filtration membrane does not require an operation such as heating, it is possible to prevent the microorganism from being affected by heat when the filtration membrane is used in a separation process using microorganisms.

One of the separation methods using a filtration membrane is a method using a hollow fiber membrane module formed by bundles of hollow fiber membranes. Traditionally, hollow fiber membrane modules have been widely used in the field of precision filtration such as sterile water, drinking water, ultrapure water production, but recently, sewage / wastewater treatment, solid-liquid separation in septic tanks, and removal of suspended solids (SS) from industrial wastewater. , Filtration of river water, filtration of industrial water, filtration of swimming pool water, and the like, and its application range is expanding.

One of such hollow fiber membrane modules is to directly immerse the hollow fiber membrane module in a water tank of a fluid to be treated and apply negative pressure to the inside of the hollow fiber membrane to selectively permeate only the fluid into the hollow fiber so that solid components such as impurities or sludge There is a suction hollow fiber membrane module that separates the If the filtration device is manufactured by adopting the suction hollow fiber membrane module, there is no need for the equipment for the circulation of the fluid, which can reduce the facility cost and the operating cost. However, there is a disadvantage in that the permeate flow rate obtained in unit time is limited.

On the other hand, in the case of a pressurized hollow fiber membrane module that pressurizes the fluid to be treated from the outside of the hollow fiber membrane to the inside, a separate equipment for circulating fluid is required, but the permeable flow rate that can be obtained in a unit time is a suction hollow fiber membrane module. Compared with the relatively large advantage.

On the other hand, when raw water containing contaminants, including solid components, is treated using the hollow fiber membrane module, the hollow fiber membrane is contaminated, and thus the permeation performance of the hollow fiber membrane is greatly degraded as the water treatment proceeds. do. Therefore, maintenance cleaning should be performed to maintain the permeation performance of the hollow fiber membranes in a good state. This maintenance cleaning is mainly performed by physical cleaning. Physical cleaning includes backwashing and aeration.

The backwashing method is a cleaning method that removes foreign matter adhering to the membrane surface by flowing back the permeated water penetrating the hollow fiber membrane through the hollow fiber membrane, whereas the air dispersing method increases the physical force of bubbles that rise by generating bubbles under the hollow fiber membrane module. And foreign matter adhering to the membrane surface by using the vibration of the hollow fiber membrane.

The water treatment operation using the hollow fiber membrane is performed by repeating the operation of performing backwashing with permeated water for 20 seconds after performing filtration for 20 minutes, and performing an acid cleaning every hour.

In order to perform backwashing, the filtration should be stopped for both suction and pressurized hollow fiber membrane modules.

On the other hand, in the case of acid cleaning, the need to stop the filtration operation depends on the type of hollow fiber membrane module. That is, in the case of the suction hollow fiber membrane module, since the filtration operation is performed while the hollow fiber membrane module is immersed in the tank containing the raw water to be treated, the air freshener cleaning may be performed during the filtration operation. On the other hand, in the case of the pressurized hollow fiber membrane module, the raw water to be treated must be continuously provided to the hollow fiber membrane module during the filtration operation. However, due to the difficulty of simultaneously injecting the raw water and air, the acid cleaning cannot be performed during the filtration operation. There was this.

That is, in the case of the pressurized hollow fiber membrane module, since the water pressure of the raw water supplied during the filtration operation is large, the air pressure provided for the acid cleaning is made smaller than the water pressure of the raw water, thereby increasing the risk that the raw water flows back to the air supply unit for the acid air.

Therefore, in the case of the pressurized hollow fiber membrane module, the filtration operation and the acid cleaning were not performed at the same time, and as a result, the decrease in the filtration capacity of the hollow fiber membrane over time was more severe than that of the immersion hollow fiber membrane module. In addition, there was a problem in that the efficiency of the water treatment operation is lowered because the filtration operation must be stopped when performing the acid cleaning.

The present invention was derived to solve the above problems, an object of the present invention is to provide a pressurized filtration device and method that can perform an acid cleaning for the filtration membrane even during the filtration operation.

As one aspect of the present invention for achieving the above object, the pressure filtration device of the present invention, a pressure filtration membrane module including a filtration membrane; Raw water supply means for supplying raw water to be filtered to the pressurized filtration membrane module; And air supply means for supplying air for cleaning the filtration membrane to the raw water while the raw water is supplied to the pressure filtration membrane module.

The air supply means can prevent backflow of raw water by providing an air pressure of 0.10 bar or more.

The air supply means may supply air to the raw water through a pipe for feeding the raw water to the pressure filtration membrane module, or directly supply air to the raw water introduced into the pressure filtration membrane module.

The pressure filtration device of the present invention may further include a non-return valve for preventing the raw water from flowing back to the air supply means. The non-return valve includes a valve body, a moving member for opening and closing a flow path formed inside the valve body, and an elastic member for elastically pressing the moving member. The backflow prevention valve may further include a separate locking step for fixing the position of one end of the elastic member. Preferably, the non-return valve further includes an O-ring inserted between the moving member and the valve body when the flow path is closed by the moving member.

As another aspect of the present invention for achieving the above object, the filtration method of the present invention using a pressurized hollow fiber membrane module comprising a hollow fiber membrane, supplying raw water to be filtered to the pressurized hollow fiber membrane module; And supplying air to the raw water for cleaning the hollow fiber membrane while the raw water is supplied to the pressurized hollow fiber membrane module.

When the water pressure of the raw water is greater than the air pressure for cleaning the filtration membrane, the air flow path may be blocked, and when the air pressure is again greater than the water pressure of the raw water, the air flow path may be opened.

According to the pressurized filtration device and the method of the present invention as described above, since the cleaning of the filtration membrane proceeds at the same time while performing the filtration using the pressure filtration membrane module, it is possible to effectively prevent contamination of the filtration membrane. In addition, it is possible to maximize the efficiency of the water treatment by minimizing the interruption of filtration during the water treatment.

On the other hand, when the non-return valve is adopted, when the air pressure provided for the acid filter cleaning of the filtration membrane becomes smaller than the water pressure of the raw water supplied during the filtration operation, the raw water may flow back to the air supply unit for the air diffuser by rapidly blocking the air supply flow path. Can be removed.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the pressurized filtration device and method according to the present invention.

The technical idea of the present invention may be applied to any filter membrane module capable of filtering solids by the water pressure of the raw water while continuously supplying raw water to be treated, regardless of the form of a filtration membrane such as a flat membrane or a hollow fiber membrane. For the purpose of illustrating the hollow fiber membrane module as an example will be described.

In addition, the technical idea of the present invention disclosed below collects permeate water only from one end of the hollow fiber membrane, as well as a two-stage collecting method using two headers to collect permeate water from both ends of the hollow fiber membrane. The same applies to the case of the single stage water collecting method using one header.

Figure 1 schematically shows a pressurized hollow fiber membrane module according to an embodiment of the present invention.

Another pressurized hollow fiber membrane module 100 according to an embodiment of the present invention includes a plurality of hollow fiber membranes 110 through which hollows are formed so that filtered water can pass from the outer surface side to the inner surface side. The plurality of hollow fiber membranes 110 have a bundle form arranged in the longitudinal direction.

At least one end portion of the plurality of hollow fiber membranes 110 is adhesively fixed to the first fixing part 120. Subsequently, a portion of the first fixing part 120 is cut in order to open a hollow at one end of the plurality of hollow fiber membranes 110.

The first fixing part 120 may be made of a thermosetting resin, for example, an epoxy resin, a urethane resin, a silicone rubber, or the like. Optionally, by incorporating fillers such as silica, carbon black, carbon fluoride, and the like into these thermosetting resins, the strength of the first fixing part 120 can be improved and the curing shrinkage can be reduced.

On the other hand, the other end portion of the hollow fiber membrane 110 is fixed to the second fixing portion 130 made of the same or different material as the first fixing portion 120. Optionally, the other end portion of the hollow fiber membrane 110 may not be fixed. In this case, the other end portion should be sealed with a thermosetting resin or the like.

It is preferable that a plurality of openings 131 are formed in the second fixing part 130 so that air for raw water to be filtered and air for cleaning with an acid is uniformly supplied to the hollow fiber membrane.

The first fixing part 120 in which the plurality of hollow fiber membranes 110 are potted is adhesively fixed to the inner surface of the module case 140 through a sealing agent. Therefore, the filtered water flowing through the hollow fiber membrane 110 and introduced into the hollow and discharged through the open end of the hollow fiber membrane 110 is prevented from being mixed with the raw water.

Raw water to be filtered is introduced into the module case 140 through the raw water inlet 150. Raw water introduced into the module case 140 is pressurized by a pump, and some of the raw water penetrates the hollow fiber membrane 110 and flows into the hollow of the hollow fiber membrane 110. The filtered water that has passed through the hollow fiber membrane 110 is discharged to the outside through the filtered water outlet 160 of the module case 140, and the raw water of which the concentration of the contaminants of the solid component is increased due to the filtered water exit (hereinafter, "concentration" Water ”is discharged to the outside through the brine outlet 170.

During the filtration operation, air for cleaning the hollow fiber membrane 110 is introduced into the module case 140 through the air inlet 180.

Optionally, raw water to be filtered and air for cleaning the hollow fiber membrane 110 may be introduced into the module case 140 through one inlet.

Figure 2 shows a filtration device according to an embodiment of the present invention.

The raw water to be filtered is pumped by the raw water supply means 300 via the circulation tank 200 to the hollow fiber membrane module 100. Filtrate that has passed through the hollow fiber membrane 110 of the raw water is sent to the filtrate tank 600, the concentrated water is sent back to the circulation tank 200.

In order to stop the filtration operation and perform backwashing of the hollow fiber membranes, the filtered water stored in the filtrate tank 600 is sent to the hollow fiber membrane module 100 by the backwash pump 700.

According to the present invention, during the filtration operation for the raw water conveyed into the hollow fiber membrane module 100, the hollow fiber membrane by the diffuser by injecting compressed air into the hollow fiber membrane module 100 using the air supply means 400 The cleaning of 110 is performed. At this time, in order to prevent the pressurized raw water to flow back to the air supply means 400, the air supply means 400 should be able to provide a sufficient air pressure to overcome the water pressure of the raw water. Given that the maximum pressure of the hydraulic pressure applied to the currently used pressurized hollow fiber membrane module is about 0.10 bar, the air supply means 400 of the present invention provides an air pressure exceeding 0.10 bar, such as a blower and a compressor. It is desirable to be able to.

As described above, the filtration device of the present invention can effectively prevent the contamination of the hollow fiber membrane 110 while performing the filtration using the pressurized hollow fiber membrane module 100 at the same time, the reverse By minimizing the disruption of filtration for cleaning, the efficiency of water treatment can be maximized.

Optionally, as in the embodiment of the present invention illustrated in FIG. 2, the raw water pressurized by installing the non-return valve 500 between the air supply means 400 and the hollow fiber membrane module 100 is provided with the air supply means 400. It can fundamentally block the possibility of backflow to the side.

According to another embodiment of the present invention shown in Figure 3, the compressed air generated by the air supply means 400 is injected into the raw water while being fed to the hollow fiber membrane module 100, the raw water injected compressed air It is introduced into the hollow fiber membrane module 100. Optionally, as shown in FIG. 3, compressed air may be supplied to the raw water through the non-return valve 500 to prevent the pressurized raw water from flowing back to the air supply means 400.

4 and 5 show the open and close states of the non-return valve 500 according to an embodiment of the present invention, respectively.

The non-return valve 500 according to the exemplary embodiment of the present invention includes a valve body 510, a moving member 520 for opening and closing a flow path formed in the valve body 510, and the moving member 520. It includes an elastic member 530 to elastically press.

One end of the elastic member 530 may be fixed to a part of the valve body 510, but one end of the elastic member 530 may be fixed by a locking step 540 formed in the valve body 510.

In order to completely prevent the inflow of raw water to the air supply means 400, the O-ring 550 is fixedly coupled to the inner surface of the valve body 510, and the O-ring 550 is attached to the movable member 520. Preferably, a groove 521 that can be press-fitted is formed. When the flow path in the valve body 510 is closed by the movable member 520, an O-ring 550 fixed to the inner surface of the valve body 510 is inserted into the groove 521 to completely block the flow of the fluid. Can be.

Hereinafter, look at the opening and closing operation of the non-return valve 500 according to an embodiment of the present invention.

First, while supplying air for cleaning the hollow fiber membrane 110 while the raw water is supplied to the hollow fiber membrane module 100, if the water pressure of the raw water is greater than the air pressure for cleaning the hollow fiber membrane 110 The moving member 520 blocks the flow path of the air by the elastic restoring force of the elastic member 530.

Subsequently, when the compressed air pressure generated by the air supply means 400 becomes greater than the water pressure of the raw water, the moving member 520 moves in the direction of opening the air passage.

Figure 1 schematically shows a pressurized hollow fiber membrane module according to an embodiment of the present invention,

Figure 2 shows a filtration device according to an embodiment of the present invention,

Figure 3 shows a filtration device according to another embodiment of the present invention,

4 and 5 show the open and closed states of the non-return valve in accordance with one embodiment of the present invention, respectively.

<Brief description of the symbols in the drawings>

100: pressurized hollow fiber membrane module 110: hollow fiber membrane

120: first fixing part 130: second fixing part

131: opening 140: module case

150: raw water inlet 160: filtered water outlet

170: concentrated water outlet 180: air inlet

200: circulation tank 300: raw water supply means

400: air supply means 500: non-return valve

510 valve body 520 moving member

521: groove 530: elastic member

540: Jam Jaw 550: O-ring

600: filtrate tank 700: backwash pump

Claims (13)

A pressure filtration membrane module including a filtration membrane; Raw water supply means for supplying raw water to be filtered to the pressurized filtration membrane module; And And an air supply means for supplying air for cleaning the filtration membrane to the raw water while the raw water is supplied to the pressure filtration membrane module. The method of claim 1, Wherein said air supply means is capable of providing an air pressure in excess of 0.10 bar. The method of claim 1, The air supply means is a pressure filtration device, characterized in that for supplying air to the raw water through a pipe for feeding the raw water to the pressure filtration membrane module. The method of claim 1, The air supply means is a pressurized filtration device, characterized in that for supplying air to the raw water introduced into the pressure filtration membrane module. The method of claim 1, And a non-return valve for preventing the back water from flowing back to the air supply means. The method of claim 5, wherein the non-return valve, Valve body; A moving member for opening and closing a flow path formed inside the valve body; And And an elastic member for elastically pressing the moving member. The method of claim 6, The non-return valve further comprises a locking jaw for fixing the position of one end of the elastic member. The method of claim 6, The non-return valve further comprises an O-ring inserted between the moving member and the valve body when the flow path is closed by the moving member. In the filtration method using a pressure filtration membrane module comprising a filtration membrane, Supplying raw water to be filtered to the pressure filtration membrane module; And And supplying air for cleaning the filtration membrane to the raw water while the raw water is supplied to the pressure filtration membrane module. The method of claim 9, And blocking the flow path of the air when the water pressure of the raw water is greater than the air pressure for cleaning the filtration membrane. The method of claim 10, And when the air pressure is greater than the water pressure of the raw water, opening the flow path of the air. The method of claim 9, The air for cleaning the filtration membrane is supplied to the raw water through a pipe for supplying the raw water to the pressure filter membrane module. The method of claim 9, Air for cleaning the filtration membrane is supplied to the raw water introduced into the pressure filter membrane module filtration method.

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