JPH06226064A - Membrane module washing method - Google Patents

Abstract

PURPOSE:To wash the membrane surface of a membrane module within a casing by providing this casing with an opening/closing port for introducing a liquid to be treated in a treating tank into the casing and effecting a membrane sepn. by the membrane module and closing this opening/closing port, then discharging the liquid to be treated in the casing and in turn introducing washing water therein. CONSTITUTION:The casing 8 of the membrane sepn. unit constituted by arranging the membrane module 11 into the casing 8 provided in the treating tank 9 is provided with the opening/closing port 12 for introducing the liquid 10 to be treated in the treating tank 9 into the casing 8 and effecting the membrane sepn. This opening/closing port 12 is closed and the liquid 10 to be treated in the casing 8 is discharged by a pump 14. The washing water is introduced in turn from a supply port 15 into the casing, by which the membrane surfaces are washed in the casing. Consequently, the easy washing of the membrane module is possible without taking the membranes out of the treating tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a membrane module of a membrane separation unit used in a water treatment facility or the like.

[0002]

2. Description of the Related Art Conventionally, this type of membrane separation unit has been shown in FIG.
As shown in the sectional view showing the entire structure of (a) and the partially enlarged sectional view of FIG. 3 (b), a plurality of membrane modules 2 are arranged in parallel at appropriate intervals in a casing 1 provided inside the treatment tank. It is configured by arranging.

In such a membrane module 2, an organic filtration membrane 4 such as an ultrafiltration membrane or a microfiltration membrane is adhered and fixed on the front and back sides of a rectangular flat plate-shaped membrane support 3. A spacer 5 such as a non-woven fabric is interposed between the organic filtration membrane 4 and the membrane support 3 to prevent the filtration membrane 4 and the membrane support 3 from adhering to each other to form a membrane permeate flow channel. . Further, a permeated liquid suction tube 6 communicating with the inside of the filtration membrane 4 is provided, and a negative pressure is applied to the inside of the membrane module 2 through this permeated fluid suction tube 6 so that the liquid to be treated in the tank passes through the filtration membrane 4 and is indicated by an arrow. A
It is suction-filtered in the direction indicated by.

An aeration device 7 for supplying oxygen or air to the liquid to be treated in the tank is provided below the membrane module 2 in the casing 1, and the arrow B is used by the aeration device 7.
As described above, oxygen or air is taken in from the outside of the tank and the bubble flow indicated by the arrow C is supplied to the gap between the membrane modules 2 to generate the gas-liquid mixed stirring flow indicated by the arrows C and D in the tank. At the same time, the cake layer attached to the surface of the film 4 is peeled and washed.

[0005]

However, when membrane clogging occurs in the above-mentioned conventional membrane separation unit,
Since the membrane modules are taken out one by one from the casing or taken out of the tank while being put in the casing for cleaning, work efficiency is low and there is a problem in safety.

The present invention solves the above problems, and an object of the present invention is to provide a membrane separation unit whose membrane surface can be easily washed.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, a method for cleaning a membrane module according to the present invention is a membrane separation unit in which a membrane module is arranged in a casing provided inside a treatment tank. In the open state, an opening / closing port for introducing the liquid to be treated in the treatment tank into the casing for membrane separation is provided, and the opening / closing port is closed to discharge the liquid to be treated in the casing, and in place of the washing water. Is introduced to wash the membrane surface in the casing.

The method for cleaning a membrane module of the present invention is
An air diffuser is provided in the lower part of the membrane module in the casing, and the membrane surface is washed with the gas-liquid mixed flow generated by aeration by the air diffuser.

The method for cleaning a membrane module of the present invention is
It is characterized in that the casing is provided with an opening and a pump is interposed, and the cleaning water introduced into the casing is circulated by the pump to clean the membrane surface with the generated circulating flow.

[0010]

With the above structure, the casing is provided with an opening / closing port for introducing the liquid to be treated in the treatment tank into the casing for membrane separation in the opened state, and closing the opening / closing port to treat the substance to be treated in the casing. By discharging the liquid and introducing washing water instead, the casing can be used as a water tank for washing to wash the membrane surface.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A membrane separation unit according to an embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 8 is a casing of the membrane separation unit, and the casing 8 has an open upper end and is immersed in the liquid to be treated 10 in the treatment tank 9. Inside the casing 8, there are several membrane modules on top.
11 are arranged, and an opening / closing port 12 that communicates the inside and outside of the casing 8 is provided in the lower part. The illustrated arrow E
Indicates the opening / closing direction of the opening / closing port 12. An opening 13 is further provided in the lower portion of the casing 8, and a pump 14 for discharging the liquid in the casing 8 to the outside of the casing 8 is connected to the opening 13. Further, above the casing 8, a wash water supply port 15 into the casing 8 is provided.

When performing membrane separation in the membrane separation unit having the above structure, the inside and outside of the casing 8 can be communicated by opening the opening / closing port 12. As a result, the liquid to be treated 10 in the entire treatment tank 9 can be solid-liquid separated by the membrane module 11.

When cleaning the film surface, the liquid level of the liquid to be treated 10 in the treatment tank 9 is lowered below the upper edge of the casing 8 so that the liquid 10 to be treated flows into the casing 8. In addition to the prevention, the opening / closing port 12 is closed to isolate the inside of the casing 8 from the region outside the casing 8 in the treatment tank 9, and then the liquid to be treated in the casing 8 is removed from the tank 9 by the pump 14.
It is discharged inside or outside the tank 9. Then, washing water can be injected into the casing 8 through the supply port 15 to wash the membrane surface in the casing 8.

An air diffuser 16 is provided in the lower part of the membrane module 11 in the casing 8, and at the time of cleaning the membrane surface, strong aeration is performed by the air diffuser 16 while the casing 8 is filled with water, whereby upward gas-liquid mixing is performed. The membrane surface can also be washed with a flow.

Further, as shown in FIG. 2, instead of the air diffusing tube 16 of the structure of the membrane separation unit of the embodiment shown in FIG.
The liquid in the casing 8 is fed to the membrane separation unit.
It is also possible to provide a circulation pipe 17 that circulates from the bottom to the top and connect it to the pump 14 to circulate the water filled in the casing 8 at the time of cleaning the membrane surface and perform the membrane cleaning by the circulating flow.

[0016]

As described above, according to the present invention, since the inside and outside of the casing can be communicated with or separated from each other by providing the opening / closing port at the lower part of the casing, it is possible to perform the membrane separation as in the conventional state and the isolation. Now the membrane module can be washed in the casing in the treatment tank. As a result, working efficiency and safety are improved as compared with the conventional method of cleaning the membrane module by taking out the membrane module or the casing in which the membrane module is arranged.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a membrane separation unit according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a membrane separation unit according to another embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a conventional membrane separation unit.

[Explanation of symbols]

 8 Casing 9 Treatment tank 11 Membrane module 12 Opening / closing port 13 Opening 14 Pump 16 Air diffuser

Claims (3)

[Claims] 1. In a membrane separation unit in which a membrane module is arranged in a casing provided inside a treatment tank, a liquid to be treated in the treatment tank is introduced into the casing in an opened state to perform membrane separation. An opening / closing opening is provided for closing the opening / closing opening, the liquid to be treated in the casing is discharged, and cleaning water is introduced instead to clean the membrane surface in the casing. Cleaning method. 2. The membrane surface is washed with the gas-liquid mixed flow generated by providing an air diffuser in the lower part of the membrane module in the casing and aerating by the air diffuser. Membrane module cleaning method. 3. A casing is provided with an opening and a pump is interposed, and by this pump, the washing water introduced into the casing is circulated, whereby the membrane surface is washed by the generated circulating flow. The method for cleaning a membrane module according to claim 1.