JPH04317793A - Water treatment apparatus - Google Patents

Abstract

PURPOSE:To prolong the time until a membrane module which is immersed in a liquid to be treated in a water treatment apparatus should be back-washed. CONSTITUTION:A membrane module 4 has membrane elements 3 which are able to filter a liquid to be treated 2. The membrane module 4 is supported by rotary shafts 11, 12 and the rotary shaft 11 is driven by a motor 14. Due to this, rotating force is given to the membrane module 4 immersed in the liquid to be treated 2 and flow speed is applied to the surfaces of the membrane elements 3 and thus scales are removed. Scale formation can be reduced even if the water treatment apparatus is operated for a long duration and the time until back washing becomes necessary is greatly prolonged.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to water treatment equipment.

0002

[Prior Art] Conventionally, water treatment equipment for treating wastewater such as sewage has been equipped with a membrane module that has a membrane element capable of filtering the liquid to be treated and is immersed in the liquid to be treated. Proposed.

FIG. 4 shows a conventional water treatment device of this type. Here, 1 is a processing tank in which a liquid to be processed 2 is stored. Inside the treatment tank 1, a membrane module 4 including a large number of tube-shaped membrane elements 3 is provided so as to be submerged in the liquid to be treated 2. The membrane module 4 has a pair of headers 5A and 5B located at both ends of the membrane element 3, and a large number of membrane elements 3 are made into a unit by these headers 5A and 5B. The header 5B also functions as a filtrate passage for collecting filtrate water filtered by each membrane element 3 and sending it to the pipe line 6. This pipe line 6 is for guiding the filtered water out of the tank, and a suction pump 7 is provided in the middle thereof. An aeration pipe 8 is provided inside the processing tank 1 below the membrane module 4, and a blower 9 outside the tank is connected to the aeration pipe 8.

In such a configuration, when air is supplied from the blower 9 to the inside of the processing tank 1 through the aeration pipe 8, the liquid to be processed 2 is lifted toward the membrane module 4 due to the air lift effect and circulated inside the processing tank 1. At the same time, the liquid to be treated 2
Aeration is performed. And suction pump 7
By operating the membrane element 3, suction negative pressure is applied to the inside of the membrane element 3, and the liquid to be treated 2 is filtered. The filtered water is taken out of the treatment tank 1 through a pipe 6.

By the way, the liquid to be treated 2 generally contains a large amount of MLS.
Since it contains S, scale gradually forms on the surface of the membrane element 3 when the water treatment apparatus having the above configuration is operated. This scale corresponds to the air blown upward from the air diffuser 8,
This air is removed to some extent by a gas-liquid multiphase flow with the liquid to be treated that flows upward due to the air lift effect of the air.

[0006] However, when the water treatment equipment is operated for a long time, the amount of scale generated on the surface of the membrane element 3 increases, and the filtration performance of the membrane element 3 decreases significantly, which hinders the operation of the equipment. There is a risk that this may occur.

Conventionally, in such a case, the pipe line 6
So-called backwashing is performed in which scale is removed by supplying pressurized fluid to the inside of each membrane element 3 and ejecting this pressurized fluid from the surface of the membrane element 3 into the inside of the processing tank 1. .

[0008]

[Problem to be solved by the invention] However, if such backwashing is performed frequently, it requires a large amount of work, which is undesirable, and the water treatment equipment itself must be operated while backwashing is being performed. However, there is a problem in that the system is unable to do so and ends up in a suspended state.

SUMMARY OF THE INVENTION It is an object of the present invention to solve these problems and to extend the time required for backwashing as much as possible.

0010

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a membrane module that has a membrane element capable of filtering a liquid to be treated and is immersed in the liquid to be treated, and a membrane module that rotates around the membrane module. The present invention is configured to include means for imparting.

[0011]

[Operation] According to this structure, by rotating the membrane module immersed in the liquid to be treated, a flow velocity is applied to the surface of the membrane element, thereby removing scale formed on the surface of the membrane element. Therefore, even if the water treatment equipment is operated for a long time, there is little scale formation, and the time until backwashing is required is significantly extended.

0012

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.
Based on this, the same members as those shown in FIG. 4 are given the same reference numerals and will be described in detail.

As shown in FIGS. 1 and 2, the membrane module 4 includes a pair of disk-shaped headers 5A, 5B and a large number of tube-shaped membrane elements 3 passed between these headers 5A, 5B. It is formed into a roughly cylindrical shape. The membrane element 3 is arranged parallel to the axial direction of the membrane module 4. A rotating shaft 11 is attached to the header 5A, and a hollow rotating shaft 12 that functions as a conduit is attached to the header 5B. Both rotating shafts 11
, 12 penetrate through the wall of the processing tank 1 so that the membrane module 4 is oriented horizontally in the immersed state, and are each rotatably supported by a bearing device 13 which also has a watertight sealing function. The rotating shaft 11 is connected to a motor 14 outside the tank. The rotating shaft 12 is connected to the header 5B so as to communicate with the inside of the header 5B, and is connected to a pipe line 16 via a rotary joint 15 outside the tank. Conduit 1
6 is provided with a suction pump 7 similar to that in FIG.

In such a configuration, when performing water treatment, the suction pump 7 and the blower 9 are operated, and the motor 14 is operated to rotate the membrane module 4 about its axis. Then, the filtered water generated by suction filtration is transferred to the membrane element 3, header 5B, hollow rotating shaft 12,
It is taken out of the tank via the rotary joint 15 and the pipe line 16.

At this time, as in the case of FIG.
The scale generated on the surface of the membrane element 3 is removed to some extent by the gas-liquid multiphase flow based on the air flow from the membrane element 3. Further, by rotating the membrane module 4, a flow velocity is generated on the surface of the membrane element 3, thereby removing scale. Note that this flow rate, that is, the relative velocity between the membrane element 3 and the liquid to be treated 2 is 0.3 to 3 m/s.
The degree is appropriate.

[0016] By effectively removing scale in this way, even if the water treatment equipment is operated for a long time, the generation of scale can be minimized, and the time until backwashing is required can be significantly shortened. It will be extended. Therefore, the number of work steps required for backwashing can be reduced, and a decrease in the operating rate of the apparatus due to backwashing can be effectively prevented.

[0017] Also, since there is less scale generation,
The amount of flux in the membrane module 4 can be increased,
Enables efficient driving. FIG. 3 shows a water treatment device according to another embodiment of the present invention. That is, in the embodiments shown in FIGS. 1 and 2, the membrane element 3 was arranged parallel to the axial direction of the membrane module 4, but here, the membrane element 3 is arranged parallel to the axial direction of the membrane module 4.
It is arranged in a twisted state so as to form an angle with the axis of the According to such a configuration, the membrane element 3 has an angle with respect to the direction perpendicular to the rotational direction of the membrane module 4, so that the liquid to be treated 2 flows in a complicated manner along the surface of the membrane element 3. . For this reason, scale removal is performed even better.

[0018]

As described above, according to the present invention, since the membrane module immersed in the liquid to be treated is rotated, a flow velocity can be applied to the surface of the membrane elements constituting the membrane module. The scale generated on the surface of the membrane element can be removed by this method. As a result, the occurrence of scale can be reduced and the time until backwashing becomes necessary can be significantly extended.

[Brief explanation of drawings]

FIG. 1 is a front view showing a schematic configuration of a water treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of the membrane module in FIG. 1;

FIG. 3 is a front view showing a schematic configuration of a water treatment device according to another embodiment of the present invention.

FIG. 4 is a front view showing a schematic configuration of a conventional water treatment device.

[Explanation of symbols]

2. Liquid to be treated 3. Membrane element 4 Membrane module 11, 12 Rotation axis 14 Motor

Claims (1)

[Claims] 1. A water filter comprising a membrane module having a membrane element capable of filtering a liquid to be treated and immersed in the liquid to be treated, and means for imparting rotation to the membrane module. Processing equipment.