JPH06343841A - Solid liquid separator and cleaning method therefor - Google Patents

Abstract

PURPOSE:To prolong the filtration duration of a dipping type membrane module and to reduce the frequency of chemical cleaning. CONSTITUTION:A back wash valve 15, a back wash pump and a back wash water tank 17 connecting to the membrane module 2 and for forcibly feeding a membrane permeated solution 9 as a washing water into the inside of the membrane are installed. Thus, since the membrane module is back washed by using the membrane permeated solution, the effect of the residual air at the time of washing by back pressure by using air or the like is avoided and the filtration duration is prolonged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to wastewater treatment, water purification treatment,
The present invention relates to a solid-liquid separation device used in sludge concentration treatment and the like.

[0002]

2. Description of the Related Art A conventional solid-liquid separation device is shown in FIG.
There is something like that shown in. The solid-liquid separation device comprises a plurality of membrane modules 2 which are immersed in water to be treated in the microorganism treatment tank 1 in parallel at regular intervals in the microorganism treatment tank 1.
An air diffusing tube 3 is provided below. The membrane module 2 has a membrane permeate flow channel inside the membrane, and this membrane permeate flow channel is connected to the water collection pipe 5 via the pipe 4. A suction pump 7 is connected to one end of the water collecting pipe 5 via a water passage valve 6,
The membrane permeate 9 can be taken out by making the inside of the membrane a negative pressure by the suction pump 7. A flow meter 8 is connected to the suction pump 7 so that the flow rate of the taken-out membrane permeated liquid 9 can be measured. At the other end of the water collection pipe 5, a compressor 11 is provided via a backwash valve 10.
Is connected to the air supply means, and the air for the back pressure cleaning can be supplied to the inside of the membrane by the air supply means. The treatment tank 1 is configured so that the water 12 to be treated is supplied from above, and a part of the mixed liquid 13 of the water to be treated and the microorganisms in the tank overflows from the upper portion of the tank 1, and the diffuser pipe 3 is It is connected to an air supply means such as a blower 14 outside the tank.

In the solid-liquid separation device having the above-mentioned structure, the water to be treated 12 is supplied into the treatment tank 1 and the water passage valve 6 is provided.
In a state where the suction pump 7 is opened and the suction force is applied by the suction pump 7, an aeration gas containing oxygen such as air is blown from the blower 14 through the diffuser pipe 3. Then, mixed solution 13
Is agitated and mixed with an agitating flow which is supplied with oxygen and is generated by bubbles, and the water 12 to be treated in the mixture 13 is treated by microorganisms. Further, the mixed liquid 13 becomes an upward flow due to bubbles such as air blown out from the air diffusing pipe 3, and is solid-liquid separated by the membrane module 2 while circulating in the tank 1.
The membrane permeated liquid 9 is taken out of the tank 1 through the pipe 4, the water collection pipe 5, and the flow meter 8. Since the deposits on the membrane of the membrane module 2 or the surface of the filter medium are separated by the circulating flow in the tank 1, the clogging of the membrane module 2 is prevented to some extent.

Then, the back pressure cleaning of the membrane module 2 is periodically performed. That is, the water flow valve 6 is closed, the backwash valve 10 is opened, and air is pressure-fed from the compressor 11. This allows the membrane module 2 to pass through the water collection pipe 5 and the pipe 4.
Air is sent to the inside of the membrane to remove the cake layer and gel layer of the sludge attached to the surface of the membrane module 2.

[0005]

However, in the conventional solid-liquid separation device as described above, the air during the back pressure cleaning remains in the membrane module and is difficult to escape even during the solid-liquid separation process. The residual air interferes with the filtration performance of the membrane module. Therefore, the amount of the permeated liquid is unevenly distributed among a plurality of membrane modules, and the chemical cleaning is performed in accordance with the membrane module whose permeated liquid amount has decreased quickly, so that the filtration duration time of the membrane module is shortened. There is a problem that the number of washings increases.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a solid-liquid separation device capable of extending the filtration duration of the membrane module and reducing the number of times of washing.

[0007]

In order to solve the above problems, the solid-liquid separation device of the present invention is provided with an immersion type membrane module in the treatment tank, and the membrane permeated liquid is supplied to the membrane module with a negative pressure inside the membrane. In a solid-liquid separation device connected with a means for taking out,
A means for connecting to the membrane module and for press-fitting a membrane permeate as washing water inside the membrane is provided.

The method for cleaning a solid-liquid separation device of the present invention is
In the above solid-liquid separation device, the membrane permeated liquid in which the cleaning chemical as the cleaning water is mixed is press-fitted inside the membrane of the membrane module, and the membrane surface deposits by the cleaning water pumped from the inside to the outside of the membrane. Is peeled off.

[0009]

With the above construction, the means for press-fitting the membrane permeation liquid as the cleaning water is provided inside the membrane, so that the membrane permeation liquid is peeled off by the membrane permeation liquid pumped from the inside to the outside of the membrane. It is possible to prevent the permeation flow rate from decreasing.

Further, by press-fitting the membrane-permeating liquid mixed with the cleaning chemical as the cleaning water into the inside of the membrane of the membrane module, the deposits on the membrane surface can be peeled and removed more favorably.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A solid-liquid separator according to an embodiment of the present invention will be described below with reference to FIG. Since this solid-liquid separation device is almost the same as the conventional solid-liquid separation device described above, members having the same configuration and the same action are designated by the same reference numerals and the description thereof will be omitted. Here, the solid-liquid separation device of the present invention is different from the conventional solid-liquid separation device in that, instead of providing a means for supplying air for back pressure cleaning such as a compressor by connecting to the water collection pipe 5, the inside of the membrane is The point is that a means for press-fitting the membrane permeate as wash water is provided in. That is, the conduit for taking out the membrane permeate 9 from the water collecting pipe 5 to the outside of the tank 1 is branched upstream of the water passage valve 6 to take out the membrane permeate 9, and the membrane permeating liquid 9 inside the membrane. Is a pipe line B for press-fitting. The pipe line B for press-fitting the membrane permeate 9 is connected to the backwash water tank 17 via the backwash valve 15 and the backwash pump 16.
Further, the pipe line A for taking out the membrane permeated liquid 9 is provided with a water passage valve 6, a suction pump 7 and a flow meter 8 and is branched at a downstream side of the flow meter 8 and has a treated water valve 18. The membrane permeate 9 as treated water 19 to the next system or a branch valve 20
And is configured to send the membrane permeate 9 to the backwash water tank 17.

In this structure, when solid-liquid separation is performed, the backwash valve 15 is closed, the water passage valve 6 is opened, and the suction pump 7
The membrane permeate 9 is allowed to pass through the conduit A by the action of. That is, the branch valve 20 is closed and the treated water valve 1
8 is opened to send the membrane permeate 9 as treated water 19 to the next system, or vice versa, the treated water valve 18 is closed and the branch valve 20
And the membrane permeate 9 is stored in the backwash water tank 17.

Then, the membrane module 2 is regularly cleaned. That is, the water passage valve 6 is closed and the backwash valve 15 is opened, and the backwash pump 16 pumps the membrane permeate 9 stored in the backwash tank 17 from the pipe B to the inside of the membrane module 2 through the water collection pipe 5. To do. Deposits such as a cake layer and a gel layer on the membrane surface are peeled and removed by the membrane permeation liquid 9 that is pressure-fed from the inside to the outside of the membrane. As a result, the problem of residual air when performing back pressure cleaning with air or the like can be avoided, and solid-liquid separation of the mixed liquid 13 can be performed with all the membrane modules 2 in the same state. As a result, it is possible to prevent a reduction in filtration continuation time, which is caused by performing chemical cleaning in accordance with the membrane module 2 whose permeated liquid amount has decreased quickly, and reduce the number of chemical cleaning of the membrane module 2. At this time, the membrane module 2 can be washed more favorably by mixing a cleaning chemical into the membrane permeate 9 stored in the backwash water tank 17.

The treatment tank can be used without being limited to the microorganism treatment tank used in the above description, and various membrane modules such as a membrane module using an ultrafiltration membrane and a ceramic tube can be used.

[0015]

As described above, according to the present invention, means for press-fitting the membrane permeate as the wash water is provided inside the membrane, and the membrane permeate is pumped from the inside to the outside of the membrane. By adopting a configuration in which the surface deposit is peeled off, it is possible to avoid the problem of a decrease in the flow rate due to residual air when performing back pressure cleaning with air or the like.

At this time, by using the membrane permeation liquid mixed with the cleaning chemicals as the cleaning water, the film surface deposit can be removed and removed more favorably. As a result, since it is possible to start the filtration process with a plurality of membrane modules in the same state, it is not necessary to quickly wash the membrane module with a membrane module having a reduced amount of membrane permeate, and the filtration duration of the membrane module as a whole is reduced. And the number of cleanings can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a solid-liquid separation device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the overall configuration of a conventional solid-liquid separation device.

[Explanation of symbols]

 1 Treatment Tank 2 Immersion Type Membrane Module 5 Water Collection Pipe 6 Water Flow Valve 7 Suction Pump 15 Backwash Valve 16 Backwash Pump 17 Backwash Water Tank

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihisa Narukami 2-6-6 Nishijima, Nishiyodogawa-ku, Osaka-shi, Osaka Kubota Shin-Yodogawa factory

Claims (2)

[Claims] 1. An immersion type membrane module is provided in a treatment tank,
In a solid-liquid separation device in which a means for taking out a membrane permeate with a negative pressure inside the membrane is connected to the membrane module, a means for connecting the membrane module and injecting a membrane permeate as wash water into the inside of the membrane is provided. A solid-liquid separation device characterized by the above. 2. The solid-liquid separation device according to claim 1,
It is characterized in that a membrane permeated liquid mixed with a cleaning chemical as cleaning water is pressed into the inside of the membrane of the membrane module, and the deposits on the membrane surface are peeled off by the cleaning water pumped from the inside to the outside of the membrane. Method for cleaning a solid-liquid separator.