JP3529054B2 - Hollow fiber membrane module assembly - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber membrane module assembly, and more particularly to a hollow fiber membrane module suitable for filtering highly polluting liquids. 2. Description of the Related Art Conventionally, hollow fiber membrane modules have been constructed using sterile water,
It has been widely used in the field of so-called microfiltration such as production of drinking water and high-purity water, and purification of air. However, recently, highly polluting water such as secondary treatment in sewage treatment plants, tertiary treatment, and solid-liquid separation in septic tanks, etc. Various studies have been made for use in processing applications. The hollow fiber membrane module used in such an application has a large clogging of the hollow fiber membrane during the filtration process. Therefore, after the filtration process for a certain time, air is sent to vibrate the hollow fiber membrane to vibrate the membrane surface. And the membrane surface washing such as passing treated water in the opposite direction to the filtration treatment is repeatedly performed. [0004] The hollow fiber membrane modules used in these fields are mostly of the cylindrical type in which hollow fiber membranes used in the field of conventional microfiltration are arranged in a circular or concentric manner. Met. Even if improvements are made, there are many that only change the filling rate or filling form of the hollow fiber membrane. [0005] Using such a conventional hollow fiber membrane module, highly polluting water (for example, ss ≧ 5)
(0 mg / L, TOC ≧ 100 mg / L), the hollow fiber membranes adhere (adhere) to each other via deposits such as organic substances attached to the surface of the hollow fiber membrane during use. By the integration, the effective membrane area of the hollow fiber membrane in the module was reduced, and a rapid decrease in the filtration flow rate was observed. [0006] Even in the case where the hollow fiber membrane module in which the hollow fiber membranes are fixedly integrated with each other as described above is regularly cleaned and backwashed, it is not easy to recover the function of the module once fixed and integrated. In addition, the cleaning efficiency was reduced. As a solution to this problem, a hollow fiber membrane is arranged in a sheet form instead of a bundled hollow fiber membrane module.
A hollow fiber membrane module in which one end or both ends of a hollow fiber membrane is fixed while maintaining an open state with a fixing member in one or two different housings. There has been proposed a hollow fiber membrane module whose vertical cross-sections are all elongated and substantially rectangular (JP-A-5-220356). [0008] In such a sheet-shaped flat hollow fiber membrane module, the hollow fiber membranes can be evenly arranged with a layer interval provided between the hollow fiber membrane modules. Therefore, the module is suitable for filtering highly polluted water, for example, because it is possible to suppress a decrease in filtration efficiency as before. In using such a module,
When treating a large amount of water, it is necessary to increase the membrane area.However, in order to increase the membrane area with one module, handling is difficult, and scrubbing and cleaning are not efficiently performed on the entire module. There is a problem that the film area becomes unnecessarily large, and the film area cannot be increased without limitation by one module. [0010] Further, even when a plurality of modules are mounted in parallel in a processing tank in order to increase the film area, one module is required.
The work of arranging and fixing each module at an appropriate position is complicated, and furthermore, it is difficult to arrange each module so that air scrubbing can be performed evenly. Therefore, there has been proposed a hollow fiber membrane module in which a plurality of sheet-shaped flat hollow fiber membrane modules are connected to a manifold having a water guide pipe for guiding a filtrate through a water collecting pipe. Such a hollow fiber membrane module assembly has a large membrane area and a compact structure. Further, since more hollow fiber membranes are in direct contact with the water to be treated, the hollow fiber membranes are firmly integrated with each other. And high filtration efficiency can be maintained for a long period of time. However, during operation and treatment using such a hollow fiber membrane module assembly, any module or hollow fiber membrane in the assembly may be damaged due to an accident. In such a case, leakage of fungi and a rapid decrease in turbidity may occur, which may lead to a decrease or loss of the function of the entire hollow fiber membrane module assembly. [0013] At this point, replacing the assembly itself is not preferred because it significantly increases processing costs. Also, if it is determined that the contamination of one module in the assembly is greater than that of another module, it is very difficult to clean only that module. According to the present invention, a compact module unit has a large membrane area,
Easy detachment, efficient scrubbing cleaning of the entire hollow fiber membrane in the module unit, and if the hollow fiber membrane or the module is damaged, remove or replace only the relevant module It is an object of the present invention to provide a hollow fiber membrane module assembly that can be used. The gist of the present invention is as follows. While keeping both ends of the sheet over preparative hollow fiber membrane in the opening state, the hollow fiber membrane comprising a hollow fiber membrane module which is fixed by a fixing member so that the shape of the both end portions becomes elongated generally rectangular by connecting a plurality In the module assembly, at each end or one end of the water collecting tube of each hollow fiber membrane module, there is a connecting member having a tube for guiding a filtrate therein, and the connecting member is generally
It has a substantially rectangular parallelepiped shape, and the side faces of the connecting member overlap each other.
Accordingly , the plurality of hollow fiber membrane modules are connected via the connecting member so that the sheet surfaces of the hollow fiber membrane modules overlap, and the connecting members are connected to each other to support the entire hollow fiber membrane module assembly. A hollow fiber membrane module assembly, comprising a connecting support portion, wherein individual hollow fiber membrane modules can be separately attached and detached. Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows a sheet-shaped flat hollow fiber membrane module having a connecting member having a pipe for guiding a filtrate inside at one end of a collecting pipe and a connecting member having no pipe at the other end. FIG. 3 is a perspective view of a hollow fiber membrane module assembly of the present invention, in which individual sheets are vertically connected to each other with the sheet surface vertical and the length direction of the hollow fibers horizontal, and individual modules can be detachably attached. FIG. 2 is a perspective view of the hollow fiber membrane module assembly of the present invention, showing a state where one module is removed and removed from the module assembly of FIG. 1 is a hollow fiber membrane, 2 is a water collecting pipe, 3 and 4 are connection support portions at the upper and lower parts of the assembly, 5 is a water pipe, 6 and 6 ′ are filtrate outlets, 7 is an opening (closed with a stopper), and 8 and Reference numeral 9 denotes a connecting member. The hollow fiber membrane 1 may be made of various materials such as cellulose, polyolefin, polyvinyl alcohol, and polysulfone, and is preferably made of a material having a high elongation such as polyethylene or polypropylene. preferable. There are no particular restrictions on the pore size, porosity, film thickness, outer diameter, etc., as long as they can be used as a filtration membrane. Considering strength and the like, a preferable example is a pore size of 0.01 to 1
μm, a porosity of 20 to 90%, a film thickness of 5 to 300 μm, and an outer diameter of 20 to 2000 μm. In addition, it is essential that the pore size is 0.2 μm or less for the purpose of removing bacteria, and in the case of removing organic substances and viruses, the pore size is limited to tens of thousands to hundreds of thousands. An external filtration membrane may be used. As the surface characteristics of the hollow fiber membrane, a so-called permanent hydrophilized membrane having a hydrophilic group or the like on its surface is desirable. As a method for producing the permanent hydrophilized membrane, a known method such as a method for producing a hollow fiber membrane with a hydrophilic polymer such as a polyvinyl alcohol type or a method for hydrophilizing the surface of a hydrophobic polymer membrane can be used. For example, examples of the hydrophilic polymer for imparting a hydrophilic polymer to the membrane surface to hydrophilize the hydrophobic hollow fiber membrane include:
Saponified ethylene-vinyl acetate copolymer, polyvinylpyrrolidone and the like can be mentioned. As another example of the film surface hydrophilization, there is a film surface polymerization method of a hydrophilic monomer, and examples of this monomer include diacetone acrylamide. Other methods include hydrophobic polymers (eg, polyolefins)
And spin-forming a film by blending a hydrophilic polymer with the polymer. Examples of the hydrophilic polymer to be used include those described above. When the surface of the hollow fiber membrane is hydrophobic, hydrophobic interaction between organic matter in the water to be treated and the surface of the hollow fiber membrane occurs, and organic substances are adsorbed on the membrane surface, which is a cause of membrane blockage. And the filter life is shortened. In addition, clogging due to adsorption is generally difficult to recover filtration performance by washing the membrane surface. By using the permanent hydrophilizing membrane, the hydrophobic interaction between the organic substance and the surface of the hollow fiber membrane can be reduced.
Adsorption of organic substances can be suppressed. Furthermore, in the scrubbing cleaning in use, the hydrophobic air causes drying and hydrophobicization due to the bubbling air, which may cause a decrease in the flux. Absent. The water collecting pipe 2 functions as a member for supporting the entire flat hollow fiber membrane module, and has an elongated, substantially rectangular opening. The opening of the water collecting pipe 2 has a substantially rectangular shape in cross section perpendicular to the hollow fiber membrane of the fixing member filled and fixed with the hollow fiber membrane therein. The connection supports 3 and 4 serve to support the entire assembly. The connection support 3 at the top of the assembly is an individual connection member 8 and the connection support 4 at the bottom is an individual connection member 9. It is configured. The connection support section 3 has a structure in which a pipe passes through the center of the connection support section so that the filtrate obtained from each water collection pipe can be collected. Accordingly, the connecting member 8 is connected to the adjacent connecting member to collect the filtrate obtained from each module,
Send to water conduit. The connection support 4 functions to integrate the connection members 9 of the individual hollow fiber membrane modules and support the entire assembly. One end of the water collecting pipe is closed by the connecting member 9. In the hollow fiber membrane module assembly of the present invention, the hollow fiber membrane modules in the assembly can be individually removed. This means that the connection support portion 3 can be divided for each connection member at any position, and the modules can be individually removed from the assembly in the state shown in FIG. At the time of module replacement, a module connected to the same connecting members 8 and 9 as the removed module is mounted. If a replacement module is not installed at that location, four openings 7 are formed in the tube in the connection support at the top of the module adjacent to the removed module, which is closed with a sealable stopper or cap. I will. The connection between the connecting members 8 and 9 does not come off due to vibration or the like during normal operation.
Also, any connection method may be used as long as the inside of the formed connection support portion 3 is kept liquid-tight with the outside. The water pipe 5 is a pipe through which the filtrate flows,
It leads to the filtrate outlet 6. The filtrate outlet 6 'provided in each connecting member 8 is closed during normal operation, but when a module is removed, particularly when two or more non-adjacent modules are removed, The filtrate can be taken out from any of the filtrate take-out ports 6 '. In the hollow fiber membrane module assembly of the present invention, in order to make the can body and the processing tank compact and to perform air scrubbing efficiently, it is preferable that the interval between adjacent sheets is small, but the interval is reduced. If it is too long, it may be difficult for air bubbles to pass between the sheets. Further, by arranging the sheets at equal intervals, uniform bubbling is performed on all the hollow fiber membrane sheets.
Appropriate spacing is required between the sheets, and the spacing is 5
A range of ６０60 mm is appropriate. Actually, the interval between sheets can be selected in consideration of the backwash conditions such as the size of the module, the number of sheets, the diameter of the water collecting pipe, and air scrubbing. In using the hollow fiber membrane module assembly of the present invention, a so-called pressure filtration method in which the module is disposed in a closed container and water to be treated is pressurized to allow the hollow fiber membrane to permeate can be adopted. It is preferable to dispose the hollow fiber membrane module assembly in an activated sludge tank, a settling tank, or the like, and use it by a suction filtration method in which a side for collecting treated water that has passed through the hollow fiber filtration membrane is suctioned. In particular, by adopting a so-called intermittent suction operation method in which suction is periodically stopped for a predetermined period of time, it is possible to efficiently prevent the deposits on the surface of the membrane from entering the internal pores. The frequency of module function recovery processing can be reduced. Since the optimum range of the intermittent suction interval varies depending on the turbidity of the water to be treated, a clear range cannot be defined. Suction time 1-30
Minutes, and a stop time of 2 seconds to 15 minutes can be mentioned as a desirable example. Further, by employing the suction filtration method, it becomes easy to circulate the treated water in the tank at the time of filtration or to wash the membrane surface by performing air bubbling.
In particular, the cleaning method using air bubbling, as described above, further enhances the cleaning effect by combining with the intermittent suction operation method that can efficiently prevent the film surface deposits from entering the inside of the film surface. Demonstrate. It is preferable that the flow of the water to be treated in the suction filtration method is made to flow substantially perpendicularly to the direction in which the hollow fiber membrane is provided, so that the effect of cleaning the surface of the hollow fiber membrane is improved. In the filtration of highly polluted water, a large amount of ss and organic substances accumulate on the film surface. Therefore, it is necessary to separate and clean the film surface using a water flow, air, vibration, ultrasonic waves, or the like. When cleaning is not performed, organic substances deposited on the membrane surface cause blockage of the membrane, resulting in a reduction in filtration life. Specific cleaning methods include so-called cross-flow filtration in which water flows parallel to the membrane surface, a method of generating a water flow in a membrane module immersion tank with a pump or a motor, a bubbling method using an upward flow of air, and vibration of the module itself. And a method of vibrating the liquid to be treated with ultrasonic waves. The cleaning may be performed continuously or intermittently depending on the progress of the film surface blockage. In the case of operating while also performing scrubbing cleaning by air bubbling, an air diffuser for performing bubbling is required. The position of the air diffuser and the module is important for proper air bubbling, but fixing the module and the air diffuser separately is a complicated operation.
Further, when the module is moved during operation, there is a problem that it is not possible to perform appropriate scrubbing cleaning during operation. As a countermeasure, if a diffuser tube is fixedly integrated with the module of the present invention, it can be easily mounted on a can or a processing tank, and appropriate scrubbing and cleaning can be continued during operation. The hollow fiber membrane module assembly of the present invention is particularly suitable for filtration of highly polluted water. Specific application fields include filtration of river water, filtration of industrial tap water, and solid-liquid wastewater. Separation, wastewater treatment (for example, treatment in a combined septic tank), and the like. The hollow fiber membrane module assembly of the present invention
Although it has a large membrane area, it has a compact structure, and more hollow fiber membranes are in direct contact with the water to be treated. , It is possible to maintain high filtration efficiency for a long time. Furthermore, since the modules in the assembly can be separately removed, if the hollow fiber membrane or the module is damaged, only the module concerned can be removed and replaced, and the module assembly can be removed. Of the filtration life can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing one example of a hollow fiber membrane module assembly of the present invention. FIG. 2 is a perspective view showing a state where one module is extracted from the assembly shown in FIG. 1; [Explanation of Symbols] 1 hollow fiber membrane 2 water collecting pipe 3 connection supporting part (upper side) 4 connection supporting part (lower side) 5 water guiding pipe 6, 6 ′ filtrate outlet 7 opening 8 connecting member (upper side) 9 connecting member ( Lower)

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Tomoyuki Furukawa               1-60, Sunadabashi 4-chome, Higashi-ku, Nagoya City, Aichi Prefecture               No. Mitsubishi Rayon Co., Ltd. Product Development Research               Inside (72) Inventor Ikuo Kinoshita               1-60, Sunadabashi 4-chome, Higashi-ku, Nagoya City, Aichi Prefecture               No. Mitsubishi Rayon Co., Ltd. Product Development Research               Inside                (56) References Japanese Utility Model Hei 5-63632 (JP, U)

Claims (1)

(57) [Claim 1] A hollow fiber fixed by a fixing member such that both ends of the sheet-like hollow fiber membrane are elongated and substantially rectangular while maintaining both ends of the hollow fiber membrane in an open state. In a hollow fiber membrane module assembly in which a plurality of membrane modules are connected, at both ends or one end of a water collecting tube of each hollow fiber membrane module, there is a connecting member having a pipe for guiding a filtrate therein, The connecting member is
It has a substantially rectangular parallelepiped shape, and the side surfaces of the connecting member overlap each other.
By connecting the plurality of hollow fiber membrane modules via the connecting members so that the sheet surfaces of the hollow fiber membrane modules overlap, the connecting members are connected to each other to support the entire hollow fiber membrane module assembly. A hollow fiber membrane module assembly, wherein each hollow fiber membrane module can be separately attached and detached.