JPH1176766A - Membrane separation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane separation device provided with a membrane cartridge, hardly causing the breaking of a filter membrane and capable of being used for a long period. SOLUTION: At the time of constituting the membrane cartridge 15, a high polymer filter membrane 15B is water-tightly fixed on the surface of a filter plate 15A at the peripheral part to form a water cut-off part 15D and a spot fixed part 15E is provided in the center part. If the filter membrane 15B is flapped in the upward direction by bubbles of an aerating air or ascending current generated thereby, the flapping is caught dispersedly by the water cut-off part 15D of the upper part and the spot fixed part 15E of the center part and then, the fatigue breaking of the filter membrane 15B is hardly caused.

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 separation device used in a water treatment facility or the like.

[0002]

2. Description of the Related Art For example, in a wastewater treatment facility, FIG.
As shown in (1), a membrane separation device 11 is immersed and installed in an activated sludge mixture 13 in an aeration tank 12. The membrane separation device 11 includes:
As shown in FIG. 5, a vertical plate-like membrane cartridge 15 is placed inside a case 14 having an open top and bottom at predetermined intervals (5 to 5).
10 mm) in parallel and the membrane cartridge 15
And a permeate pipe 17 communicating with the permeate flow path of each membrane cartridge 15.

At the time of treatment, the raw water 19 is introduced into the aeration tank 12, and nitrogen and organic substances in the raw water 19 are removed by the action of activated sludge in a state where aeration air is jetted from the air diffuser 16. The activated sludge mixture 13 in the tank is filtered by the membrane cartridge 15, and the permeated liquid permeating the membrane surface of the membrane cartridge 15 is led out of the tank by the permeated liquid pipe 17. At this time, the membrane surface of the membrane cartridge 15 is washed by the bubbles of the aerated air from the air diffuser 16 and the rising water flow generated thereby.

[0004]

As shown in FIG. 6, the membrane cartridge 15 has a polymer filter membrane 15B disposed on both surfaces of a synthetic resin filter plate 15A, and a peripheral edge of the filter membrane 15B. Is fixed to the filter plate 15A in a watertight manner by bonding or welding (water stop portion 15D).
The air bubbles and the rising water flow of the above-described aerated air are generated by the membrane cartridge 1.
When ascending the gap between the five, the filtration membrane 15B is pushed upward as shown in FIG. At that time, the filtration membrane 15B is mainly pulled upward in the lower part and the side part of the membrane cartridge 15, while the entire filtration membrane 15B is pushed like a wave toward the upper water stopping part 15D in the upper part of the membrane cartridge 15. The upper water stop 15D is more susceptible to fatigue damage due to the impact than the lower or side water stop. When a part of the filtration membrane 15B is broken in this way, the whole membrane cartridge 15 becomes unusable, and must be repaired or replaced promptly.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a membrane separation device provided with a membrane cartridge which is hardly damaged by a filtration membrane and can be used for a long time.

[0006]

In order to solve the above-mentioned problems, the present invention relates to an immersion type membrane separation apparatus in which vertical membrane cartridges are arranged at predetermined intervals above an air diffuser. While fixing the cartridge to the surface of the filter plate with a polymer filtration membrane in a peripheral portion thereof in a watertight manner,
It is characterized in that the spot is fixed at the center.

[0007] As the polymer filtration membrane, a filtration membrane portion integrally formed on the surface of a sheet portion which can be a permeate flow path,
Alternatively, a filtration membrane having no sheet portion can be used, and such a polymer filtration membrane can be fixed by an adhesive or ultrasonic welding.

According to the above-described structure, even if the filtration membrane is fueled upward by the bubbles of the aerated air ejected from the air diffuser and the rising water flow generated by the air bubbles, the fuel is lifted by the upper fixed part and the central part. Of the filtration membrane, the fatigue damage is less likely to occur than in the conventional filter in which the entire filter membrane is concentrated only on the upper portion, and the life of the membrane cartridge is extended.

Also, when performing a chemical cleaning operation of injecting sodium hypochlorite, oxalic acid solution, etc. into the permeate side, the swelling of the filtration membrane due to the injection of the chemical is greatly suppressed by the presence of the spot fixing portion, thereby suppressing the elongation. Therefore, also by this, the air bubbles and the rising water flow during the filtration operation are reduced, and the life of the membrane cartridge is extended.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. Since the membrane separation device of the present invention has almost the same configuration as the conventional one shown in FIG.
The illustration and description of the overall configuration will be omitted, and a description will be given of a plate-shaped membrane cartridge that is arranged in parallel with a predetermined interval above the air diffuser with a membrane surface facing up and down in the membrane separation device.

In FIG. 1, a membrane cartridge 15 is a filter plate (width 50 cm × height 100 cm) 15A made of synthetic resin.
And a polymer filtration membrane 15B covering almost the entire surface of the filter plate 15A.

The filter plate 15A is formed with a water collecting portion (not shown) penetrating the filter plate 15A in the thickness direction, and a permeated liquid extracting nozzle 15C communicating with the water collecting portion is provided. The polymer filtration membrane 15B is formed by integrally forming a filtration membrane section on the surface of a sheet section which can be a permeate flow path, and is fixed to the filter plate 15A by an adhesive at the periphery of the membrane in a watertight manner. At the same time, spot fixing (about 1 cm ² ) is carried out by ultrasonic welding at two places at equal intervals in the vertical direction at the center in the width direction. Reference numeral 15D denotes a water stop portion formed by watertight fixing, and 15E denotes a spot fixing portion.

According to the above-described configuration, even if the filtration membrane 15B is fueled upward by the bubbles of the aerated air ejected from the air diffuser or the rising water flow generated by the air bubbles, the fueling is performed as shown in FIG. In the upper part, the water blocking part 15D and the central spot fixing part 15E are dispersed and received, so that fatigue damage is less likely to occur than the conventional one in which the entire filter membrane 15B is concentrated only on the upper part, The life of the membrane cartridge 15 is extended.

After the membrane cartridge 15 is used for a certain period of time, a chemical cleaning operation of injecting sodium hypochlorite, oxalic acid solution or the like into the permeate is performed. The swelling of the filtration membrane 15B due to the injection of the chemical solution is greatly suppressed by the presence of the liquid, and the elongation of the filtration membrane 15B is suppressed. Therefore, the air bubbles and the rising water flow during the filtration operation are smaller than the conventional one. As a result, the life of the membrane cartridge 15 is extended.

Table 1 below shows the results of examining the peel strength of the above-mentioned membrane cartridge of the present invention and a conventional membrane cartridge manufactured similarly except that the spot is not fixed.

The measurement object is a conventional membrane cartridge, the membrane cartridge of the present invention (both immersed in an aeration tank for one year and put to practical use), and a new membrane cartridge (conventional membrane cartridge which is not used. ).

The peel strength is measured at a predetermined measurement position at the periphery of the film sheet (A: center in the width direction of the upper end, B: center in the width direction of the lower end, C: center in the vertical direction of the right end, D: center in the vertical direction of the left end). A notch with a constant area (2.5 cm width) is cut in the center, the edge at the center side is pinched, pulled outward in the direction of 180 °, the tension at the time of tearing is measured, and the measured value X (kg) is measured. It was determined by dividing by the width of the sheet (2.5 cm).

[0018]

[Table 1]

From Table 1, the strength decrease in the upper part (part A) is calculated to be 21% in the conventional type membrane cartridge, whereas it is calculated to be 7.9% in the membrane cartridge of the present invention. It can be seen that the strength reduction has been greatly improved.

The position and number of the spot fixing portions may be determined according to the size of the filtration membrane. For example, in the case of a membrane cartridge made of the same material and having the same size as shown in FIG. As shown, fatigue fixation can be further reduced by fixing the spot at a total of six locations, two at equal intervals in the width direction and three at equal intervals in the vertical direction.

[0021]

As described above, according to the present invention, not only is the filter membrane fixed to the filter plate at the periphery but also to the center when the flat membrane cartridge is arranged vertically. By fixing the spot at the part, the upward movement of the filtration membrane due to aerated air or rising water can be dispersed and received by the upper fixed part and the central spot fixed part, which reduces Since the fatigue damage can be reduced as compared with the conventional one that concentrates on the portion, the life of the membrane cartridge can be extended. In addition, the elongation of the filtration membrane due to the cleaning with the chemical solution can be reduced by the spot fixing portion. This also makes it possible to reduce the vibration caused by the bubbles and the rising water flow during the filtration operation, thereby extending the life of the membrane cartridge.

[Brief description of the drawings]

FIG. 1 is a front view of a membrane cartridge arranged in a membrane separation device of the present invention.

FIG. 2 is a vertical cross-sectional view for explaining the movement of the filtration membrane by aerated air or water flow in the membrane cartridge of FIG.

FIG. 3 is a front view of another membrane cartridge.

FIG. 4 is an explanatory view showing a state in which a conventional membrane separation device is immersed and installed in an aeration tank.

FIG. 5 is a partially cutaway perspective view showing the entire configuration of the membrane separation device.

FIG. 6 is a front view of a conventional membrane cartridge.

FIG. 7 is a vertical cross-sectional view for explaining the movement of the filtration membrane by aerated air or water flow in the membrane cartridge of FIG.

[Explanation of symbols]

 11 Membrane separation device 15 Membrane cartridge 15A Filter plate 15B Polymer filtration membrane 15D Water stop section 15E Spot fixing section 16 Air diffuser

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Seiji Izumi 2-47 Shishitsu Higashi 1-chome, Naniwa-ku, Osaka-shi, Osaka

Claims (1)

[Claims] 1. An immersion type membrane separation device in which a vertical plate-like membrane cartridge is arranged at a predetermined interval above an air diffuser, wherein the membrane cartridge has a polymer filtration membrane on a surface of a filter plate and a peripheral portion thereof. At the same time as fixing watertight,
A membrane separation device wherein a spot is fixed at a central portion.