JP2000189958A - Immersion type membrane filter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-liquid separator and the washing method for restraining growth of a cake layer on a separation membrane surface which is a factor for lowering a transmission flow flux and effectively remove the grown cake layer. SOLUTION: The separation membrane is hold in a protective cylinder 4 having an opened port at the lower edge, and having a water passing port 45 on the upper part side face, and the upper edge of a flow path inside the membrane of the separation membrane is opened on the upper end of the protective cylinder 4 to connect to a separated liquid discharge tube 9, and also the upper end part of the protective cylinder 4 is fixed to a suspending frame 7 of the protective cylinder 4 provided so as to enable to move vertically with respect to a solid-liquid separation tank 3, and a cylinder 6 being a driving means for vertically oscillating the suspending frame 7 of the protective cylinder 4 is provided on the upper part of the solid-liquid separation tank 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an immersion type membrane filtration apparatus, and more particularly to an immersion type membrane filtration apparatus used for water purification treatment, waste water treatment and the like.

[0002]

2. Description of the Related Art Conventionally, solid-liquid separation is performed using a flat membrane-like separation membrane such as a nonwoven fabric, a microfiltration membrane, an ultrafiltration membrane, or a fine mesh screen. A solid-liquid separator is used for water purification treatment, waste water treatment, and the like. In such a solid-liquid separation device, a separation membrane is immersed in raw water in a solid-liquid separation tank, and the inside of the membrane is relatively depressurized so that only the liquid (treated water) flows from the outside to the inside of the separation membrane. The liquid is allowed to permeate, whereby solid-liquid separation is performed.

On the other hand, the solids in the raw water become attached to the surface of the separation membrane by the above-mentioned solid-liquid separation operation, so that the solids gradually accumulate as the operation proceeds, forming a cake layer and separating the separation membrane. The capacity, ie the permeation flux, will be reduced. Therefore, conventionally, air is diffused from below the separation membrane, water or air is caused to flow backward from the suction side of the separation membrane, or high-pressure water is sprayed on the membrane surface to physically separate the cake layer on the membrane surface. Or chemical cleaning with chemicals.

[0004] Generally, an air diffuser provided below the separation membrane is used to supply 0.7 to 1.0 m to a unit sectional area of the separation membrane.
/ Min is aerated for about 1 to 2 minutes to remove the deposits on the entire film surface by the effect of the resulting swirling flow of gas-liquid two-phase flow and the vibration of the film due to bubbles to recover the permeation flux. ing. Further, backwashing in which water is passed from the secondary side (inner side) of the membrane at a washing speed of about 1.5 to 2.5 m / min with respect to a unit cross-sectional area of the separation membrane for 10 to 30 seconds is used in combination, The effect of improving the separation effect of the deposit is also performed by the effect.

[0005] Further, in a powdered activated carbon circulating membrane filtration device, powdered activated carbon is added to a solid-liquid separation tank to adsorb and remove soluble organic substances in water, thereby improving the quality of treated water. The powdered activated carbon stays in the solid-liquid separation tank until the saturated adsorption amount is reached, and the adsorption / filtration operation is repeated.As time passes, the activated carbon slurry adheres to the surface of the separation membrane and grows to form a cake layer. Is formed. As a result, the filtration form exhibits cake filtration, but shows a phenomenon in which the permeation flux gradually decreases.

In this case as well, it is possible to partially recover the permeation flux by performing the above-described physical cleaning. However, in order to further enhance the cleaning effect, the amount of air diffused and the backwashing speed are reduced. Means such as increasing the time or changing each time are conceivable, but this is not realistic due to the problem of energy efficiency and the durability of the film material. In addition, it is difficult to uniformly wash the entire membrane surface by air diffusion and backwashing,
A dead space is generated, and the cake layer tends to grow from the dead space.

On the other hand, cleaning with a chemical solution must be carried out at appropriate intervals because not only solid substances adhering to the membrane surface but also scale can be removed. Must be taken out and transferred to a chemical solution tank, which is troublesome, has problems such as the cost of the chemical solution, and adversely affects the life of the separation membrane. Therefore, it is not advisable to frequently wash the chemical solution.

Accordingly, the present invention provides a solid-liquid separation apparatus which can suppress the growth of a cake layer on the surface of a separation membrane, which is a factor of reducing the permeation flux, and can effectively peel off the grown cake layer. It is intended to provide such a cleaning method.

[0009]

Means for Solving the Problems In order to achieve the above-mentioned object, a immersion type membrane filtration device of the present invention is a solid-liquid separation device for performing solid-liquid separation by a separation membrane immersed in a solid-liquid separation tank. Opening, holding the separation membrane in a protective cylinder having a water inlet on the upper side, opening the upper end of the intra-membrane flow path of the separation membrane to the upper end of the protective cylinder, connecting to the separation liquid outlet pipe, and The upper end is fixed to a protective cylinder hanging frame provided so as to be movable up and down with respect to the solid-liquid separation tank, and driving means for swinging the protective cylinder hanging frame up and down is provided above the solid-liquid separation tank. The solid-liquid separation tank is further provided with an air diffuser at the bottom thereof.

[0010]

FIG. 1 is a cross-sectional view showing an embodiment of an immersion type membrane filtration device according to the present invention, FIG. 2 is a partial cross-sectional front view showing an example of a protective cylinder, and FIG. It is a top view which shows an example of the hanging frame fixed.

This immersion type membrane filtration apparatus immerses a separation membrane 5 housed in a protective cylinder 4 in a solid-liquid separation tank 3 having a raw water inflow pipe 1 and a drain pipe 2 and an upper end of the protective cylinder 4. Is supported by a protective cylinder hanging frame 7 that moves up and down by a cylinder 6. At the bottom of the solid-liquid separation tank 3, there is provided an air diffuser 8 capable of diffusing at least the inside of the protective cylinder 4.

As shown in FIG. 2, the protective cylinder 4 comprises a cylindrical body 41 having an open top and bottom. The separation membrane 5 has an upper part held by a bundling plate 42 and a lower part formed by a stay vertical bar 43.
And is held by a stay horizontal bar 44 attached to the arm.
Further, a water passage 45 is provided on the upper side surface of the protective cylinder 4, and an upper part of the water passage 45 is sealed with an adhesive sealant 46. Further, an end plate 48 provided with an O-ring 47 around the periphery is attached to the upper end of the protection cylinder 4.
By attaching the end of the separation liquid outlet pipe 9 to the end plate 48, the flow path in the membrane of the separation membrane 5 and the separation liquid outlet pipe 9 are connected.

As shown in FIG. 3, the protective cylinder hanging frame 7 is formed by forming a pair of horizontal frames 71 and a plurality of vertical frames 72 in a ladder shape. The cylindrical body 41 of the protective cylinder 4 is inserted into the rectangular space defined by 72. A rod 61 of the cylinder 6 mounted on a frame 31 suspended over the solid-liquid separation tank 3 is connected to the protective cylinder hanging frame 7. The frame 7 is suspended in the solid-liquid separation tank 3 so as to be vertically movable.

That is, by operating the cylinder 6 to expand and contract the rod 61, the protection cylinder 4 can be swung up and down via the protection cylinder hanging frame 7. When the protection cylinder 4 is moved up and down in this way, the water in the solid-liquid separation tank 3 moves up and down in the cylinder 41 through the lower end opening of the protection cylinder 4 and the water passage 45, so that the cylinder 4
In 1, a water flow is generated along the surface of the separation membrane 5.

Therefore, when a certain amount of solid matter adheres and accumulates on the membrane surface, or by periodically operating the cylinder 6 to move the protection cylinder 4 up and down, the separation membrane 5
Can be washed away by the water flow in the cylindrical body 41, and the growth of the cake layer can be suppressed. At this time, since washing is performed by a water flow parallel to the membrane surface, strong force is not applied to the separation membrane 5,
The peeling effect can be enhanced without causing damage. In addition, since the separation membrane 5 is housed in the protection cylinder 4 having a water passage section at the top and bottom and is integrally moved up and down, the entire separation membrane 5 can be uniformly contacted with the water flow. The entire film 5 can be uniformly washed.

The stroke of the cylinder 6 at this time is
Usually, it is about 200 mm, and the vertical movement speed is 85 mm /
sec. Vertical movement speed 85
By setting it to about mm / sec, it is possible to obtain about 5 times the strength of air diffusion (air scrubbing), and it is possible to greatly enhance the shearing effect of the cake layer.

Further, at this time, by using back washing and air diffusion from the air diffuser 8 together, the cake layer on the film surface can be more effectively peeled off. For example, by moving the protective cylinder 4 up and down after backwashing to make the cake layer float from the membrane surface, the cake layer can be efficiently peeled off,
Then, by performing aeration, the peeled cake layer can be completely removed from the separation membrane 5 and can be flown out of the protective cylinder 4.

As a result, the growth of the cake layer can be suppressed more reliably as compared with the conventional washing operation by backwashing or aeration, so that a predetermined permeation flux can be maintained for a long period of time, and the chemical solution washing can be performed. Can be greatly reduced. Therefore, even if the equipment cost and the cylinder operating energy are increased due to the mechanical equipment such as the protective cylinder and the cylinder, the total cost can be reduced by reducing the operation and maintenance.

The shape of the protective cylinder and the hanging frame can be appropriately selected according to the separation membrane to be used, and a plurality of protective cylinders can be mounted on one hanging frame. You can use more than one depending on its ability. In addition, an appropriate guide member may be provided in the solid-liquid separation tank in order to surely move the suspension frame and the protection cylinder up and down. Further, it is also possible to use driving means other than the cylinder, for example, a combination of a motor and a crank.

[0020]

As described above, according to the immersion type membrane filtration device of the present invention, the growth of the cake layer on the surface of the separation membrane can be suppressed and the grown cake layer can be effectively separated. This can significantly reduce the maintenance and management costs of the immersion type membrane filtration device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of an immersion type membrane filtration device of the present invention.

FIG. 2 is a partial cross-sectional front view showing an example of a protection cylinder.

FIG. 3 is a plan view showing an example of a suspension frame.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Raw water inflow pipe, 2 ... Drain pipe, 3 ... Solid-liquid separation tank, 4 ... Protection cylinder, 5 ... Separation membrane, 6 ... Cylinder, 7 ... Protection cylinder hanging frame, 8 ... Aeration pipe, 9 ... Separation liquid extraction Tube, 31 ... frame,
41: cylindrical body, 42: bundling plate, 43: stay vertical bar, 44:
Stay horizontal bar, 45 ... water inlet, 46 ... adhesive sealant, 47 ...
O-ring, 48 end plate, 61 rod, 71 horizontal frame, 7
2. Vertical frame

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Claims (2)

[Claims] 1. A solid-liquid separation device for performing solid-liquid separation by a separation membrane immersed in a solid-liquid separation tank, wherein a lower end is opened,
Holding the separation membrane in a protective cylinder with a water inlet on the upper side,
A protective cylinder provided with the upper end of the intra-membrane flow path of the separation membrane opened to the upper end of the protective cylinder and connected to the separation liquid outlet pipe, and the upper end of the protective cylinder provided to be vertically movable with respect to the solid-liquid separation tank. A submerged membrane filtration device, wherein a driving unit fixed to a suspension frame and swinging the protection cylinder suspension frame up and down is provided above the solid-liquid separation tank. 2. The immersion type membrane filtration device according to claim 1, wherein an air diffuser is provided at the bottom of the solid-liquid separation tank.