JPH06327948A - Solid-liquid separator - Google Patents

Abstract

PURPOSE:To prolong the filtration continuation time of membrane modules and to reduce the number of washing times on the whole by discharging air for backwashing remained inside the membrane modules, by an exhaust means connected to the membrane modules thereby preventing the lowering of filtration performance of the membrane module due to the remained air. CONSTITUTION:To immersion type membrane modules 2 installed in a treatment tank 1, a suction pump 7 for evacuating the inside of the membranes to take out a membrane permeate liquid and a compressor 11 for forcibly feeding air for backwashing to the inside of the membranes are connected. An exhaust valve 15 for exhausting the air for backwashing is provided, and is connected to the membrane modules 2. The air for backwashing remained in the inside of the membrane modules is discharged by means of the exhaust valve 15 to prevent the lowering of filtration performance of the membrane modules due to remained air, thus a filtration process for water to be treated is performed with all the membrane modules being in the same state. As a result, the filtration continuation time of the membrane modules is prolonged to reduce the number of washing times on the whole.

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 is provided with a plurality of membrane modules 2 which are immersed in water to be treated in a microbial treatment tank 1 in parallel at regular intervals, and an air diffuser 3 is provided below the membrane module 2. ing. The membrane module 2 has a membrane permeate flow passage inside the membrane, and this membrane permeate flow passage is connected to a water collection pipe 5 via a pipe 4. A suction pump 7 is connected to one end of the water collection pipe 5 via a water passage valve 6, and the membrane permeate 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 1 is provided via a backwash valve 10.
1, an air supply means such as 1 is connected, and the air for back pressure cleaning can be supplied to the inside of the membrane by this air supply means. The treatment tank 1 is configured so that the water to be treated 12 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 13 outside the tank.

In the above structure, the water 12 to be treated is supplied into the treatment tank 1, the water passage valve 6 is opened, and the suction force is applied by the suction pump 7. Blow in an aeration gas containing oxygen such as air. Then, the mixed liquid 13 is agitated and mixed by an agitating flow generated by the supply of oxygen and bubbles, and the water 12 to be treated is treated by microorganisms. At this time, the mixed liquid 13
Becomes an upward flow due to air bubbles such as air blown out from the air diffusing tube 3, and is solid-liquid separated by the membrane module 2 when passing between the membrane modules 2, and the membrane permeate 9 is the pipe 4 and then the water collecting pipe 5. It is taken out of the tank 1 through the flow meter. The cake layer or gel layer of sludge formed on the surface of the membrane or the filter medium of the membrane module 2 is separated by the upward flow, and the clogging of the membrane module 2 is prevented.

Then, while continuing the treatment, the membrane module 2 is back-pressure washed periodically, for example, for 10 seconds every hour. That is, the water flow valve 6 is closed and the backwash valve 10 is opened,
By sending air from the compressor 11, sludge and the like adhering to the surface of the membrane module 2 is peeled off.

[0005]

However, in the conventional solid-liquid separation device as described above, air during back pressure washing remains in the membrane module and is difficult to escape even when entering the solid-liquid separation process. The residual air interferes with the filtration performance of the membrane module. Therefore, there is a problem that the amount of the permeated liquid is unevenly distributed among the membrane modules, and the filtration duration time of the membrane modules is shortened.

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 the membrane module is washed.

[0007]

In order to solve the above-mentioned 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 module is provided with a negative pressure inside the membrane to permeate the membrane. In the solid-liquid separation device in which the means for taking out the air and the means for injecting the air for back pressure cleaning into the inside of the membrane are connected, an exhaust means capable of discharging the air for back pressure cleaning by connecting to the membrane module. It is provided.

[0008]

With the above structure, the air for back pressure cleaning remaining in the membrane module can be discharged to the outside of the system by the exhaust means connected to the membrane module. As a result, the deterioration of the filtration performance due to the residual air can be prevented, and the filtration duration of the membrane module can be lengthened.

[0009]

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 an exhaust means which is an exhaust valve 15 is provided above the water collection pipe 5.

In the solid-liquid separator having this structure, when the back pressure washing of the membrane module 2 is completed, the water passage valve 6 and the back washing valve 1
0 is closed and the exhaust valve 15 is opened to exhaust the air inside the membrane module 2 through the pipe 4 and the water collection pipe 5. As a result, deterioration of the filtration performance of the membrane module 2 due to residual air can be prevented, and solid-liquid separation of the water to be treated 12 can be performed with all the membrane modules 2 in the same state. As a result, it is possible to prevent a decrease in filtration continuation time and reduce the number of times the membrane module 2 is washed.

The treatment tank is not 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.

[0012]

As described above, according to the present invention, the exhaust means is provided so as to be connected to the membrane module, and the exhaust air means exhausts the air for back pressure cleaning remaining inside the membrane module to obtain the residual air. Since the filtration performance of the membrane module is prevented from lowering due to the above, the filtration process of the water to be treated can be performed with all the membrane modules in the same state. As a result, the filtration duration of the membrane module becomes longer as a whole, and the number of times of cleaning 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 Tube 7 Suction Pump 11 Compressor 15 Exhaust Valve (Exhaust Means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshihisa Narukami No. 6, Nishijima, Nishiyodogawa-ku, Osaka-shi, Osaka Prefecture 6-1, Kubota Shin-Yodogawa factory (72) Masahiko Shioyama 2 Nishijima, Nishiyodogawa-ku, Osaka-shi, Osaka Chome 1-6, Kubota Co., Ltd. Shin-Yodogawa Factory

Claims (1)

[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 and a means for injecting air for back pressure cleaning into the membrane are connected to the membrane module, the solid-liquid separation device is connected to the membrane module. A solid-liquid separation device comprising an exhaust means capable of exhausting the air for back pressure cleaning.