JPH04247285A - Method for filtering using hollow fiber filter module and production of hollow fiber filter module - Google Patents

Abstract

PURPOSE:To prevent clogging in a hollow fiber filter module which is dipped in a reaction tank for filtering to biologically treat org. matter-contg. water. CONSTITUTION:Such a module is used for filtering that includes hollow fiber 2 by <=3% area in the whole area of a fixing member 3. Or, two parallel thread material are disposed with a certain interval, on which hollow fiber is successively wound to form a wound body and then this wound body is fixed to obtain a module.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of filtration using a hollow fiber filtration module in the biological treatment of organic matter-containing water, and a method of manufacturing a hollow fiber filtration module suitable for use in the filtration.

0002

[Prior Art] Hollow fibers (also called ``hollow fiber membranes'' or ``hollow fiber filtration membranes'' in some cases) that have a large number of very fine pores were developed to remove fine particles, which are impurities in water. ) is easy to manufacture because there is no need to reinforce and support the thin filtration membrane with a support, and it is also possible to make a hollow fiber module with many fibers, and by increasing the number of fibers, the filtration capacity can be increased. Since it is easy to do so, a practical device can be easily made.

Although this hollow fiber has an excellent water purification function, when applied to fields where it is necessary to filter a large amount of water containing relatively large amounts of fine colloidal substances and metal ions, the hollow fiber The threads tend to become clogged, and in order to recover from the clogging, water is flowed from inside the hollow fibers and flows backwards, and air bubbles are raised from below and applied to the hollow fibers to give them physical vibrations. was considered. but,
In this method, the air bubbles do not reach the inside of the hollow fiber filtration module made up of a large number of hollow fibers, so clogging is difficult to eliminate.

In particular, a hollow fiber filtration module has a large number of U-shaped hollow fibers, approximately 5,000 pairs, tied together at the opening, hardened with adhesive to form a fixing member, and the surrounding area is By surrounding it with surrounding members, a hollow fiber filtration module with approximately 10,000 hollow fibers is manufactured. Thread clogging occurs easily and is difficult to clear.

[0005] Conventionally, therefore, in order to provide sufficient spacing between the hollow fibers, the end portions of the U-shaped hollow fibers were
A structure in which the bottom of the character portion is hooked onto each piece of the support member and held therein has been considered (publication of Utility Model Publication No. 2-13069).

[0006] In order to reduce the density of the hollow fibers in the fixing member that bundles the openings of the hollow fibers, rather than at the ends of the hollow fiber filtration module, it is possible to The ratio R of the occupied cross-sectional area (St) of the hollow fiber and the internal cross-sectional area (Sr) of the annular member is 0.11 and 0.6.
A hollow fiber filtration module has been proposed in which the value is between 0 and 0 (Japanese Unexamined Patent Publication No. 60-255115). In this module, it is necessary that the installation density of the hollow fibers in the fixing member be within a specific range in order to effectively utilize the hollow fibers and improve the recovery of the filtration function.

However, in the past, the module was usually installed and used in a pipe through which liquid flows;
If the filling rate is reduced, the fixing member becomes larger and the tube becomes thicker, which is not practical.

[0008]

[Problem to be Solved by the Invention] Recently, when organic wastewater such as sewage is treated biologically, a solid-liquid separator is usually installed after the biological treatment tank and the sludge is separated by sedimentation. Instead of the previous method, a method has been proposed in which the hollow fiber filtration module is installed in a biological treatment tank and the hollow fiber permeated water is taken out from there, omitting the solid-liquid separator. . According to this method, membrane-permeated water with almost zero SS can be obtained, so there is an advantage that there is no need to take measures such as coagulation and separation to remove SS from the separated water from the solid-liquid separation tank.

However, in this method, since the sludge in the treatment tank is gradually concentrated, the SS concentration is high and the hollow fibers are likely to become clogged, particularly between the hollow fibers. This is because the treatment liquid that enters between the hollow fibers sucks water and the sludge hardens between them, acting like a binder and solidifying as if the hollow fibers were bundled together, reducing the overall filtration area. As a result, the permeation flux becomes small.

[0010] Such a phenomenon has been reported in the above-mentioned Japanese Patent Application Laid-open No. 1983-
Even when using the hollow fiber filtration module described in 255115, this problem could not be avoided. This is because this module is intended for water purifiers that process large amounts of water, such as nuclear reactor condensate, that contains relatively large amounts of metal ions and extremely fine colloidal substances. It cannot handle liquids.

[0011] The present invention provides filtration using a hollow fiber filtration module that does not easily cause clogging even when installed in a biological treatment tank and quickly recovers filtration performance, and manufactures a module suitable for this purpose. The purpose is to find out how to do it.

0012

[Means for Solving the Problems] The present invention was able to solve the above objects by the following means.

1. Fixing of the hollow fiber filtration module is used in a filtration method in which the hollow fiber filtration module is immersed in a reaction tank for biologically treating organic matter-containing water, allowing water to permeate from the outside of the hollow fiber to the inside, and then taking it out of the tank as a filtrate. A filtration method characterized by using a hollow fiber filtration module in which the total area occupied by hollow fibers in the member accounts for 3% or less of the total area of the fixed member (referred to as "filling ratio").

2. Sequentially winding the hollow fibers around two filaments or strips arranged in parallel with an interval between them so that the hollow fibers are stretched over the filaments or strips at a pitch of a certain distance,
The hollow fibers are fixed to one of the filamentous bodies or a band-like body, and the tensioned filament body thus formed is wound in a spiral shape around one end, and the hollow fibers of the wound body are fixed to the filamentous body or band-like body. Hollow fiber filtration in which the filling rate of the hollow fibers in the fixing member is 3% or less, characterized in that the fixing member is formed by bonding the body side parts with an adhesive and cutting the end of the bonded part. How the module is manufactured.

In the hollow fiber filtration module used in the filtration method of the present invention, the ratio of the total area occupied by the hollow fibers in the fixing member to the total area of the fixing member, that is, the filling rate is 3% or less, means that the hollow fibers This means that hollow fibers are loosely present in the fixing member that binds the fibers, and because the hollow fibers are spaced apart from each other, liquid flow or air bubbles can easily enter between the hollow fibers, and the sludge It is less likely to get clogged. In the above module, the smaller the filling rate, the less likely sludge clogging will occur, but if it is too small, the total area of the fixing member will become too large.
Alternatively, the number of hollow fibers attached to the fixing member decreases, and the amount of water that can permeate decreases, so it cannot be made too small from the economical point of view.
The content is preferably 1% or more, preferably 0.5% or more. In this case, it is preferable to make the intervals between the hollow fibers as uniform as possible.

[0016] The length of the hollow fiber is limited from the point where it can effectively permeate water, and the length of the hollow fiber is 60 to 70 mm up to the end of the U-shaped bottom.
It is normal to use cm. Hollow fiber pore diameter is 0.01μ
Those in the range of m to 1 μm are commonly used.

Various materials can be used for the hollow fibers, including cellulose, polyolefin, polysulfone, and polyvinyl alcohol. Among these, those having excellent durability and excellent filtration performance include polyolefin-based porous hollow fiber membranes, and for example, polyethylene-based porous hollow fiber membranes are preferably used.

FIG. 1 shows a plan view of a hollow fiber filtration module 1 as an example used in the present invention. The hollow fibers 2 exist as uniformly as possible in the fixing member 3, and the annular member 4 surrounds the fixing member 3. FIG. 2 is a partially vertical side view of the module shown in FIG. 1, in which the U-shaped portion at the lower end of the hollow fiber 2 is hooked onto and held by a support member 5. The support member 5 is supported by a column 6 connected to the annular member 4. This structure is common to conventional hollow fiber filtration modules except for the filling rate of the hollow fibers.

In forming the hollow fiber filtration module used in the present invention, it is preferable to uniformly distribute the hollow fibers in the fixing member. The periphery is surrounded by an annular member, the gap between which is filled with adhesive, etc., and the parts are joined together, and the upper part of the annular member is cut horizontally to form an opening for each hollow fiber. For this reason, it is difficult to maintain a constant spacing between each hollow fiber, and for example, it is technically difficult to insert a thin spacer between each hollow fiber at a fixing member, and it requires manual labor. Become. However, manually manufacturing a hollow fiber filtration module made up of 10,000 hollow fibers requires manpower and a long time.

The method for manufacturing a hollow fiber filtration module of the present invention allows for easy manufacture of a hollow fiber filtration module with a low filling rate, and as shown in FIG. Two thread-like bodies (or band-like bodies)
7 and 8, the hollow fiber 2 is connected from the upper filament 7 to the lower filament 8.
The hollow fibers are wound at a pitch of a certain distance so as to be stretched from the bottom to the top, and the contact portions between the upper filament 7 and the hollow fibers are fixed with an adhesive or the like. At that time, if the upper and lower filaments 7 and 8 are moved in the same direction at a constant speed, the hollow fibers 2 can be wound and stretched around the upper and lower filaments 7 and 8 one after another at the same position. Can be done. In this manner, the number of hollow fibers 2 stretched between the upper and lower filaments 7 and 8 is 1. 1 million books
The set is wound spirally around one end, and the hollow fibers of the wound body are bonded by filling the gap on the side of the fixed filament with a fixing agent such as adhesive, and the bonded part is Cut the end of the hollow fiber horizontally, that is, perpendicular to the direction of extension of the hollow fiber. This results in a hollow fiber assembly having a flat end with a large number of hollow fiber openings.

A hollow fiber filtration module is obtained by using this end as a fixing member and surrounding it with an annular member. At this time, the above-mentioned filling rate can be changed by changing the thickness or thickness of the thread-like body or band-like body 7 used and the pitch distance of the hollow fibers fixed to it, so both of the above conditions are selected. By doing so, the filling rate can be set to 3% or less.

[0022] By this method for manufacturing a hollow fiber filtration module, a hollow fiber filtration module that can be used in the filtration method of the present invention can be easily obtained.

Further, the lower ends of each U-shaped hollow fiber 2 of the module thus formed may be supported or fixed using a support member 5 so that the mutual spacing between them is widened. In addition, since the filamentous body (or band-like body) 8 used in forming the tension body in manufacturing the module is for forming the hollow fibers 2 into a U-shape with a certain length, the tension body Since it is unnecessary after the formation of the tension body, it may be removed, and the timing of its removal may be selected as appropriate, such as immediately after the tension body is formed, or if it is better for the tension body winding work, after the winding body is formed. be able to. If necessary, this filamentous body 8 may be used to hold the hollow fiber 2.

[0024]

[Function] In the filtration method of the present invention, the hollow fiber filtration module used therein has a filling rate of hollow fibers of 3% or less in its fixing member, so the hollow fibers are present very sparsely, and the hollow fibers are mutually separated. Since the interval is quite wide,
Even when used in a reaction tank for biologically treating water containing organic matter such as organic sewage, clogging is unlikely to occur, and the entire module or a group of hollow fibers will not harden into a rod-like shape. . In conventional hollow fiber filtration modules, the hollow fibers are tightly bundled in the fixed member, so
Since the hollow fibers are in close contact with each other near the center of the module, when the water to be treated that has entered between them is suction-filtered by the hollow fibers, subsequent inflow of the water to be treated through the gaps between the hollow fibers is difficult. As a result, as filtration continues, the activated sludge in the liquid is strongly dehydrated, causing the hollow fibers to stick to each other and become rod-shaped.However, in the present invention, the hollow fibers in the fixing member Since the filling rate is as described above, the hollow fibers are not in close contact with each other, and the disadvantages of the conventional method do not occur.

[0025]

[Examples] The present invention will be specifically explained below with reference to Examples. However, the present invention is not limited to this example.

Example 1 A polyethylene hollow fiber having a cross-sectional area of 0.118 mm 2 was wound and stretched at a pitch of about 5 mm using filament bodies 7 and 8 arranged in parallel at an interval of 65 cm. The lower thread-like body has been removed from the stretched thread body, which is then wound for about 50 m, the base of the wound body thus formed is tightened with a band, and the gap between the hollow fibers is impregnated with adhesive to bond them together. The joint was cut horizontally to form a fixing member, which was surrounded by an annular member to form a hollow fiber filtration module having approximately 5000 U-shaped hollow fibers with a length of 60 cm to the end. The diameter of the fixing member was 28 cm. The filling rate of hollow fibers in this hollow fiber filtration module is approximately 1.9%.
Met.

[0027] Using this hollow fiber filtration module, BO
MLSS that treats organic wastewater with D200ppm is 10
The sample was immersed in a biological treatment tank using an activated sludge method maintained at a concentration of 1,000 ppm, and filtered by suction from the inside of the hollow fiber to obtain permeated water. The permeation flux at this time is 0.2m3
/m2 ·day, and there was almost no decrease even after 30 days. Further, no clogging occurred.

For comparison, it has about 5,000 U-shaped hollow fibers, and the diameter of the fixing member is about 7 cm (filling rate of hollow fibers is about 4).
When filtration was performed in the same biological treatment tank using a hollow fiber filtration module with a
/m2 - 0.02m3 /m2 after 10 days
・Clogging occurred, and more than half of the hollow fibers became stick-shaped.

[0029]

Effects of the Invention In the filtration method of the present invention, the hollow fiber filtration module used has a filling rate of hollow fibers in the fixed member of 3.
Since the hollow fibers are spaced sufficiently apart from each other, the flow of treatment liquid between the hollow fibers is not obstructed, making it suitable for biological treatment tanks with relatively high concentrations of activated sludge, etc. However, clogging hardly occurs. As a result, the permeation flux in this module is large and hardly decreases.

Furthermore, in this module, the results are even more remarkable when the ends of the hollow fibers are held so as to be spread apart so that a large distance from each other is maintained. Further, in the manufacturing method of the hollow fiber filtration module of the present invention, it is possible to simply and easily manufacture a module in which U-shaped hollow fibers having the same length are arranged at the same spacing or density as possible on the fixing member. can. It can be manufactured by mechanical operations, and a desired filling rate can be obtained by changing the thickness of the filament or band and the pitch of the hollow fibers fixed thereto.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a hollow fiber filtration module as an example used in the filtration method of the present invention.

FIG. 2 is a partially longitudinal side view of the module of FIG. 1;

FIG. 3 is a schematic diagram of a tensioned fiber body used in manufacturing the hollow fiber filtration module of the present invention.

[Explanation of symbols]

1 Hollow fiber filtration module 2 Hollow fiber 3 Fixed member 4 Annular member 5 Support members 6 Pillar 7. Filamentous body 8. Filamentous body 9 Fixed part 10 tension body

Claims (2)

[Claims] Claim 1: A filtration method in which a hollow fiber filtration module is immersed in a reaction tank for biologically treating organic matter-containing water, and water permeates from the outside of the hollow fibers to the inside, and is taken out of the tank as a filtrate. Filtration characterized by using a hollow fiber filtration module in which the total area occupied by the hollow fibers in the fixing member of the thread filtration module occupies 3% or less of the total area of the fixing member (referred to as "filling ratio"). Method. [Claim 2] Hollow fibers are sequentially wound around two thread-like bodies or strip-like bodies arranged in parallel with an interval between them at a pitch of a certain distance so as to be stretched across the filament-like bodies or strip-like bodies,
The hollow fibers are fixed to one of the filamentous bodies or a band-like body, and the tensioned filament body thus formed is wound in a spiral shape around one end, and the hollow fibers of the wound body are fixed to the filamentous body or band-like body. Hollow fiber filtration in which the filling rate of the hollow fibers in the fixing member is 3% or less, characterized in that the fixing member is formed by bonding the body side parts with an adhesive and cutting the end of the bonded part. How the module is manufactured.