JP2001179060A - Internal pressure type membrane treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal pressure type membrane treatment device, in which a membrane flux is drastically raised by addition of a simple installation and filtrating treatment efficiency is enhanced. SOLUTION: In the internal pressure type membrane treatment device, in which raw water is supplied to the inside of a hollow fiber membrane and filtrating operation is performed, a gas introducing means for mixing gas with raw water flowing into the hollow fiber membrane is provided and raw water is allowed to flow to the inside of the hollow fiber membrane in a gas-liquid mixing state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal pressure type membrane treatment apparatus, and more particularly, to an internal pressure type membrane treatment apparatus which supplies raw water to the inside of a hollow fiber membrane and performs a filtration operation.

[0002]

2. Description of the Related Art An internal pressure type membrane treatment apparatus performs a filtration operation by supplying raw water inside a hollow fiber membrane forming a membrane module. The raw water is circulated through the hollow fiber membrane by a circulation pump. The system is operated by a cross-flow filtration system that takes out the membrane-treated water (membrane filtered water) that has passed through the hollow fiber membrane. In such an internal pressure type membrane treatment apparatus, a backwash treatment is performed in which backwash water is periodically supplied to the permeated water side (outside) of the hollow fiber membrane to remove dirt attached to the raw water side (inside) of the membrane. There is a need.

[0003]

During the above-mentioned backwashing process,
Since the filtration operation must be temporarily stopped, the operation efficiency of the membrane processing apparatus can be increased if the cycle of performing the backwashing process can be lengthened. That is, if the membrane flux can be increased, the filtration process can be continued for a long time, and the cycle of the backwashing process can be lengthened to increase the operation efficiency of the apparatus.

Accordingly, an object of the present invention is to provide an internal pressure type membrane treatment apparatus capable of greatly increasing the membrane flux by adding simple equipment and improving the filtration efficiency.

[0005]

In order to achieve the above object, an internal pressure type membrane treatment apparatus according to the present invention is directed to an internal pressure type membrane treatment apparatus for supplying raw water inside a hollow fiber membrane and performing a filtration operation. Gas supply means for mixing gas with raw water flowing into the yarn membrane is provided.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a system diagram showing one embodiment of the internal pressure type membrane processing apparatus of the present invention. This internal pressure type membrane treatment apparatus mixes raw water supplied from a raw water pump 10 with air supplied from an air supply path 11, and then mixes the circulating pump 1
2, the raw water is supplied from the raw water supply unit 13 to the inside of the hollow fiber membrane of the membrane module 14, and the membrane filtered water that has passed through the hollow fiber membrane flows out of the treated water outflow unit 15, and the circulating water The raw water flowing out to the outflow portion 16 is circulated to the upstream side of the circulation pump 12 by the circulation path 17, and the air separated from the circulated water is discharged from the exhaust pipe 19 through the air release valve 18. .

[0007] As described above, by mixing gas such as air with raw water and supplying it to the inside of the hollow fiber membrane in a state containing air bubbles, dirt attached to the inner surface of the hollow fiber membrane is removed to some extent by the action of the gas-liquid interface. Since it can be removed, it is possible to perform a filtration treatment operation in which clogging of the membrane is suppressed. Therefore, it is possible to improve the effect of suppressing membrane clogging at the time of circulating filtration, so that a long-time filtration operation can be performed by setting the membrane flux several times higher than the membrane flux when the operation is performed by circulating only raw water. It can be carried out.

[0008] Air supply path 11 constituting gas introduction means
The supply of air from the circulation pump 12 may be performed using a pressurized air supply facility such as an air compressor, and an appropriate means can be adopted according to the suction side pressure of the circulation pump 12.
Also, the supply of air may be performed at all times during the filtration operation,
It can be performed intermittently at appropriate intervals. Further, by changing the supply amount of air, the pressure and flow rate of the raw water flowing into the membrane module 14 can be varied to improve the dirt removal effect. Further, nitrogen or oxygen other than air may be supplied.

FIG. 2 is a system diagram showing a modification of the internal pressure type film processing apparatus of the present invention. In this embodiment, the internal pressure type membrane processing apparatus is provided with an ejector 2 in a stage preceding the circulation pump 12.
1 and the suction side pipe 22 of the ejector 21 is connected to the exhaust pipe 19.

[0010] By forming in this manner, the air separated from the circulating water can be suctioned by the ejector 21 and reused, so that the amount of air supplied from the air supply path 11 to the circulation line can be reduced. . Thereby, power consumption in the pressurized air supply equipment of the air supply path 11 can be reduced, and stable operation can be performed with less energy. The air sucked by the ejector 21 is preferably air having relatively high pressure before and after the air release valve 18.
Depending on the capacity of (1), it is possible from the atmosphere, and auxiliary equipment such as a blower can be provided.

In both embodiments, the supply and mixing of air (gas) is not limited to the preceding stage of the circulating pump 12, and an appropriate position can be selected. For example, in an environment where high-pressure air can be obtained, the raw water supply unit 13 at the subsequent stage of the circulation pump 12
High pressure air can also be supplied to the side. Further, air can be supplied before and after the raw water pump 10, and the circulation path 17 can be used.

[0012]

As described above, according to the internal pressure type membrane treatment apparatus of the present invention, clogging of the hollow fiber membrane can be suppressed by the action of gas bubbles mixed with raw water flowing into the hollow fiber membrane. Therefore, a long filtration operation can be performed with a high membrane flux.

[Brief description of the drawings]

FIG. 1 is a system diagram showing one embodiment of an internal pressure type film processing apparatus of the present invention.

FIG. 2 is a system diagram showing a modified example of the internal pressure type film processing apparatus of the present invention.

[Explanation of symbols]

10 Raw water pump, 11 Air supply path, 12 Circulation pump, 13 Raw water supply unit, 14 Membrane module, 15
Treated water outflow section, 16: circulating water outflow section, 17: circulation path,
18 ... air vent valve, 19 ... exhaust pipe, 21 ... ejector, 22 ... suction side piping

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Claims (1)

[Claims] 1. An internal pressure type membrane treatment device for supplying raw water to the inside of a hollow fiber membrane and performing a filtration operation, wherein gas introduction means for mixing gas with the raw water flowing into the hollow fiber membrane is provided. Pressure processing system.