JP2002346344A - Immersed filtration apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an immersed filtration apparatus which can facilitate the peeling of suspended solids deposited on the outer surfaces of hollow fiber membranes, discharge the peeled suspended solids easily outside a hollow fiber membrane cartridge, and prevent the accumulation of impurities in the upper and lower end parts of the hollow fiber membranes. SOLUTION: In an immersed membrane separator for filtering raw water while the surfaces of the hollow fiber membranes are cleaned by air ejected from air diffusion pipes installed in the lower parts of the hollow fiber membranes, in the immersed filtration apparatus, the upper and lower parts of the hollow fiber membranes are adhesion-fixed, air can be introduced into a hollow fiber bundle in a lower fixed part, the upper and lower fixed parts are connected to each other and fixed by at least two rods or pipes, a hollow fiber membrane cartridge in which the hollow fiber membranes are substantially exposed is used, the peripheral side surface of the hollow fiber bundle of the hollow fiber cartridge is shorter than the length of the hollow fiber membrane bundle, in an outer wall with the upper and lower parts opened, the hollow fiber bundle is housed to be exposed between the upper end of the outer wall and the upper adhesion-fixed part and between the lower end of the outer wall and the lower adhesion-fixed part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter for immersion. More specifically, the present invention relates to an immersion type membrane filtration device in which a hollow fiber membrane is immersed in a tank or a tank to perform solid-liquid separation in purification treatment of human waste, sewage, domestic wastewater, industrial wastewater, or the like.

[0002]

2. Description of the Related Art A hollow fiber membrane is immersed in a conventional tank or tank,
An example of an immersion filtration device that provides an air diffuser tube below the hollow fiber membrane and removes impurities adhering to the hollow fiber membrane with air ejected from the air diffuser tube is disclosed in Japanese Patent Application Laid-Open No. 61-107905. The lower part of the hollow fiber membrane (the upper part is adhesively fixed and the lower free end) is opened, housed in the outer wall longer than the hollow fiber membrane, and a diffuser tube is provided below it to perform air bubbling,
A filtration device for vibrating a hollow fiber membrane to remove impurities adhered to the surface of the hollow fiber membrane and washing the same is described. However, since the lower end of the hollow fiber membrane is a free end, when performing air bubbling during filtration, when the air flow rate increases, the hollow fiber membrane floats up or the hollow fiber membranes are entangled with each other,
Cleaning may not be sufficient. In particular, this phenomenon is remarkable when the diameter of the cartridge is large, which may hinder a long-term filtration operation.

[0003]

DISCLOSURE OF THE INVENTION The present invention makes it easy to peel off a suspension deposited on the outer surface of a hollow fiber membrane,
It is an object of the present invention to provide an immersion filtration device capable of easily discharging a peeled suspension out of a hollow fiber membrane cartridge and preventing the accumulation of impurities on the upper and lower ends of the hollow fiber membrane. .

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, as an immersion filter, air blown out of a diffuser tube is fixed to a lower end of a hollow fiber membrane. The raw water is introduced from the outer wall opening of the outer periphery of the hollow fiber membrane bundle on the lower adhesive fixing part, and the concentrated liquid and air are adhered to the upper end of the outer wall by the air draft effect at that time. The release from the open portion of the outer wall between the fixing portions is suitable for the purpose, and the present invention has been accomplished based on this finding.

That is, the present invention is as follows. 1) The upper and lower ends of a hollow fiber membrane are bonded in a immersion membrane separation device that filters the stock solution while washing the surface of the hollow fiber membrane with air blown out from a diffuser installed below the vertically suspended hollow fiber membrane. It is fixed, the lower adhesive fixing part has a structure capable of introducing air into the hollow fiber bundle, the upper and lower adhesive fixing parts are connected and fixed by two or more rods or pipes, and the hollow fiber membrane is substantially exposed. A hollow fiber membrane cartridge is used, and the outer peripheral side surface of the hollow fiber membrane bundle of the hollow fiber membrane cartridge is shorter than the length of the hollow fiber membrane bundle. A hollow fiber membrane bundle is housed so as to be exposed between the lower adhesive fixing portion and the lower adhesive fixing portion.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of an immersion filtration apparatus according to the present invention. FIG. 1 is an explanatory cross-sectional view showing an embodiment of a filter device for immersion according to the present invention, and FIG. In FIG. 1, in the present invention, the upper portion of the bundled hollow fiber membranes 3 is integrally connected to the inside of the cartridge head 2 and is adhesively fixed. The hollow fiber membrane 3 on the side of the cartridge head 2 has an open end. Further, the lower portion of the bundled hollow fiber membranes 3 is integrally bonded and fixed inside the skirt 4, and the end of the hollow fiber membrane 3 on the skirt 4 side is sealed. As illustrated in FIG. 2, the skirt 4 is formed with a plurality of through holes 4b for introducing air released from the air diffuser tube into the inside of the hollow fiber membrane bundle and effectively contacting the outer peripheral surface of each hollow fiber membrane. ing.

The hollow fiber membrane 3 used in the present invention includes:
Ultrafiltration membranes and microfiltration membranes are preferred in terms of pore size. The cartridge head 2 serves as a fixing portion when suspending the hollow fiber membrane cartridge in the immersion type filtration device, and also serves as a seal portion for separating raw water and filtered water. Therefore, the cartridge head 2 has a suspending, fixing, and sealing function. It has a combined shape. For example, a step may be provided on the outer peripheral portion, a groove may be provided, or a flange portion protruding radially outward may be provided. The radial cross section of the cartridge head 2 may be square, hexagonal, elliptical, or the like, in addition to the circular shape. However, the sealing property between the cartridge head 2 and the adhesive fixing portion and the ease of manufacturing the filtration tank are easy. Therefore, a circle is preferable.

The through hole 4b provided in the adhesive fixing layer 4a (lower adhesive fixing portion) on the skirt side of the present invention is a hole formed in the adhesive fixing layer itself, and the size of the through hole is an equivalent diameter of 2 mm. A range of ３０30 mm is preferred. Here, the equivalent diameter is defined as 4 × (cross-sectional area of flow path) / (peripheral side length). Examples of the shape of the through hole include a polygon such as a triangle, a square, and a hexagon, a circle, an ellipse, a sector, a C-shape, and a star. The number of through holes depends on the cross-sectional area of the cartridge and the number of threads, but is preferably 2 to 300. The positions of the through holes are distributed on the adhesive fixing cross section at a certain adhesive fixing cross section, for example, at the intersection of the multiple circle and the radial line, the intersection of the lattice, or the position of the vertices of many equilateral triangles. It is preferably provided, particularly preferably a large amount at the center of the hollow fiber membrane bundle.

In the present invention, the skirt 4 preferably protrudes from the end of the hollow fiber membrane 3 and is adhered and fixed to the hollow fiber membrane bundle to form an air chamber 4c surrounded by the adhesive fixing layer and the skirt. The length of the skirt 4 protruding from the end face of the hollow fiber membrane depends on the diameter of the cartridge, the amount of supplied gas, and the diameter and number of through holes.
Preferably it is ~ 200 mm. The cross-sectional shape of the skirt 4 in the radial direction may be a circle, a square, a hexagon, an ellipse, or the like, in addition to a circle. However, when a cartridge is mounted on the filtration tank, the same shape as the cartridge head may be used. Preferred, especially circular.

The cartridge head 2 adhesive fixing layer (upper adhesive fixing portion) and the skirt 4 adhesive fixing layer (lower adhesive fixing portion)
It is connected and fixed by two or more rods or pipes to suppress bending and twisting in the lateral direction. The size of the connecting rod or pipe is preferably in the range of an equivalent diameter of 2 mm to 30 mm. Here, the equivalent diameter is defined as 4 × (cross-sectional area) / (peripheral side length). Examples of the shape of the connecting or fixing rod or pipe include a polygon such as a triangle, a square, and a hexagon, a circle, an ellipse, a sector, a C-shape, and a star.
In particular, those having a circular shape are preferable. The number is
Depending on the cross-sectional area of the cartridge and the number of yarns, 2-30
The number is preferably, and the position is not particularly limited. However, it is preferable that the members are arranged so that a force from below can be uniformly received during air bubbling. For example, it is preferable to arrange them at equal intervals on the outer periphery of the yarn bundle or to disperse them in the yarn bundle.

The outer wall 7 used in the present invention is shorter than the hollow fiber membrane exposed in the hollow fiber membrane cartridge. The length is preferably 1 to 30 cm shorter than the length of the hollow fiber membrane exposed in the hollow fiber membrane cartridge, and more preferably 2 to 10 cm shorter. The outer wall is preferably 1.1 to 3 times the equivalent diameter of the skirt 4, more preferably 1.2 to 2 times. Here, the equivalent diameter is defined as 4 × (cross-sectional area) / (peripheral side length). The cross-sectional shape of the outer wall 7 may be circular, square, hexagonal, elliptical, or the like, but is preferably the same shape as the hollow fiber membrane cartridge.

In the hollow fiber membrane cartridge, the outer peripheral side surface of the hollow fiber membrane bundle is shorter than the length of the hollow fiber membrane bundle, and is provided in an open outer wall between the upper end of the outer wall and the upper adhesive fixing portion and the lower end of the outer wall. The hollow fiber membrane bundle is housed so as to be exposed between the adhesive fixing portions. The outer wall 7 is fixed by, for example, a header pipe 8 or a diffuser pipe.

[0013]

Embodiment 1 Hereinafter, an embodiment (FIG. 1) of operating a submerged filtration device in which a hollow fiber membrane cartridge according to the present invention is suspended and fixed to a treated water header pipe will be described. In FIG. 1, the hollow fiber membrane is suspended by a cartridge head 2 on a treated water header pipe 8 via a gasket by a clamp,
Fixed. In the above configuration, during a filtration operation by the immersion type filtration device, raw water is supplied to the immersion tank 1 from a supply water inlet 10 provided above the immersion tank 1 by a pump (not shown).

The air bubbling of the hollow fiber membrane is carried out in a state of being filled with raw water in the immersion tank 1 from the diffuser pipe 6 provided at the lower part in the form of bubbles into the immersion tank 2.
It is collected by the skirt 4, passed through the through hole 4 b of the adhesive fixing layer 4 a, and guided to the outer peripheral side surface inside each hollow fiber membrane 3. At this time, the water in each bundle of the hollow fiber membranes is stirred and the respective hollow fiber membranes 3 are vibrated to separate the suspension adhered to the surface of the hollow fiber membranes 3. The air which vibrated the hollow fiber membrane 3 and the concentrated raw water containing the separated impurities are discharged into the immersion tank 1 from the outer wall opening on the cartridge head side.

The raw water in the immersion tank 1 is guided to each hollow fiber membrane 3 from the opening at the lower end of the skirt 4 and the outer wall 7 by air draft by air bubbling in the hollow fiber membrane. Raw water near the outer periphery of each hollow fiber membrane 3 is negatively filtered from the outside to the inside of the hollow fiber membrane 3, and the filtered water is guided to the treated water header pipe 8 from the open upper end of the hollow fiber membrane 3. . The filtrate in the treated water header pipe is discharged from the treated water outlet provided in the immersion tank 1 to the outside of the immersion tank 1.

In the above filtration apparatus, synthetic sewage is supplied as raw water, and the activated sludge concentration (MLSS) in the immersion tank is supplied.
Was maintained at 8000 to 12000 mg / L, and air bubbling of 1 Nm ³ / hr per 1 m ^{3 of} membrane area was performed.
In the 0 KPa negative pressure filtration operation, the flux is 1 m / day at 1 m / day.
I was able to drive stably for months. The composition of the synthetic sewage used was as follows. Heptonic 0.35 (g / L) meat extract 0.23 Urea _{0.05 NaCl 0.05 KCl 0.015 CaCl 2 0.015} MgS0 4 0.012 K 2 HPO 4 0.935 KH 2 PO 4 0.117 Tap water

[0017]

According to the filtration apparatus of the present invention, each hollow fiber membrane is vibrated by air bubbling to facilitate separation of suspended matter deposited on the outer surface of the hollow fiber membrane, and hollow fiber membrane is formed by air draft by air bubbling. And the separated suspension can be easily discharged out of the hollow fiber membrane cartridge. Further, the lower end of the hollow fiber membrane can prevent the accumulation of impurities by inflow of raw water, and the upper end of the hollow fiber membrane can prevent accumulation of impurities by discharging air and concentrated water.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing an example of an embodiment of a filter device for immersion according to the present invention.

FIG. 2 is an enlarged view of a main part showing a configuration of a lower skirt portion of the hollow fiber membrane of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Immersion tank 2 Cartridge head 3 Hollow fiber membrane 4 Skirt 4a Adhesive layer 4b Through hole 4c Air chamber 5 SUS pipe 6 Air diffuser 7 Outer wall 8 Header piping 9 Support pipe 10 Supply water inlet

Claims (1)

[Claims] 1. An immersion membrane separation apparatus for filtering a stock solution while washing the surface of a hollow fiber membrane with air blown out from an air diffuser provided below a vertically suspended hollow fiber membrane. The lower adhesive fixing part has a structure that can introduce air into the hollow fiber bundle, the upper and lower adhesive fixing parts are connected and fixed by two or more rods or pipes, and the hollow fiber membrane is substantially exposed. The hollow fiber membrane cartridge has a hollow fiber membrane cartridge, and the outer peripheral side surface of the hollow fiber membrane bundle is shorter than the length of the hollow fiber membrane bundle. And a dipping filter device wherein the hollow fiber membrane bundle is housed between the lower end of the outer wall and the lower adhesive fixing portion so as to be exposed.