JPH09220569A - Solid-liquid separator - Google Patents

Abstract

PURPOSE: To extend the filtering continuation time of a membrane module and to reduce the number of times of chemical washing by providing a membrane permeated liquid suction means to the upper part of a water collecting pipe and providing a back pressure washing air pressure introducing means to the lower part thereof. CONSTITUTION: A membrane permeated liquid suction means comprising a water valve 6, a suction pump 7 and a flowmeter 8 is provided to the upper end of a water collecting pipe 5. A backwashing valve 10 and a compressor 11 are provided to the lower end of the water collecting pipe 5 so as to introduce back pressure washing air into the water collecting pipe 5 under pressure. By this constitution, back pressure washing air is sent from the lower end of the water collecting pipe 5 under pressure to equally supply compressed air to respective membrane modules 2 to increase washing effect. Further, by sucking a membrane permeated liquid from the upper end of the water collecting pipe 5, air at a time of back pressure washing can be easily removed and the lowering of a permeated liquid flow rate caused by residual air can be prevented. Therefore, all of the membrane modules 2 are set to the same state to make it possible to perform the solid-liquid separation of a mixed liquid 13. The lowering of a filtering continuation time is prevented and the number of times of chemical washing can be reduced.

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 the lower end of the water collection 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. A compressor 11 is installed at the upper end of the water collection pipe 5 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 such 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 air diffuser 3 is It is connected to an air supply means such as a blower 14 outside the tank 1.

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 permeate 9 is taken out of the tank 1 through the pipe 4, then the water collecting pipe 5 and the flowmeter 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 by the compressor 11. As a result, air is sent to the membrane module 2 through the water collection pipes 5 and 4, and the cake layer and gel layer of sludge attached to the surface of the membrane module 2 are removed.

[0005]

However, in the conventional solid-liquid separation device as described above, the membrane permeate is taken out from the lower end of the water collecting pipe, and the air for back pressure cleaning is supplied from the upper end of the water collecting pipe. Since it is configured, the air at the time of back pressure cleaning remains in the membrane module, and it is difficult to escape even during the solid-liquid separation step, and the residual air hinders the filtration performance of the membrane module. Therefore, the amount of membrane permeate varies among the membrane modules, and the chemical cleaning is performed in accordance with the membrane module whose permeate volume has decreased quickly. There is a problem that

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 lengthening the filtration duration of the membrane module and reducing the number of times of chemical cleaning.

[0007]

In order to solve the above problems, a solid-liquid separation device of the present invention is provided with a plurality of immersion type membrane modules in a treatment tank, and each membrane module is connected to a water collecting pipe to collect water. In a solid-liquid separation device configured to take out a membrane permeate by applying a negative suction pressure to the inside of the membrane through a water pipe, a means for aspirating the membrane permeate is provided on the upper part of the water collection pipe, and the reverse part is provided on the lower part of the water collection pipe. A means for pressurizing air for pressure cleaning is provided.

In the solid-liquid separation device of the present invention, the membrane module is divided into a plurality of membrane module groups according to the water depth, and a water collecting pipe is provided in each membrane module group.

[0009]

With the above-described structure, the means for injecting the air for the back pressure cleaning into the lower part of the water collecting pipe is provided, so that the compressed air is uniformly supplied to each membrane module, and the cleaning effect is increased. Further, by providing the means for sucking the membrane permeated liquid on the upper part of the water collecting pipe, the air at the time of the back pressure cleaning can be easily removed, and the permeation flow rate due to the residual air can be prevented from lowering.

[0010]

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 a means for sucking the membrane permeated liquid is provided at the upper end of the water collecting pipe 5 and a means for pressurizing air for back pressure washing is collected. It is a point provided at the lower end of the water pipe 5. That is,
A water passage valve 6, a suction pump 7, and a flow meter 8 are provided at the upper end of the water collection pipe 5, and a backwash valve 10 and a compressor 11 are provided in the water collection pipe 5.
It was installed at the lower end of.

With this structure, the air for back pressure cleaning is pumped from the lower end of the water collecting pipe 5, so that compressed air is uniformly supplied to each membrane module 2 and the cleaning effect is increased. Further, since the membrane permeated liquid 9 is sucked from the upper end of the water collection pipe 5, the air at the time of back pressure cleaning can be easily removed, and the reduction of the permeation flow rate due to the residual air can be prevented. As a result, it is possible to perform solid-liquid separation of the mixed liquid 13 with all the membrane modules 2 in the same state, so that the filtration continuation time is reduced due to chemical cleaning in accordance with the membrane module 2 whose permeated liquid amount has decreased quickly. Can be prevented, and the number of times of cleaning the membrane module 2 with a chemical can be reduced.

[0012] Instead of the above structure, the membrane module is divided into a plurality of membrane module groups according to the water depth, and a water collecting pipe is provided in each membrane module group, whereby compressed air is supplied to each membrane module more evenly. In addition, this air can be easily removed.

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.

[0014]

As described above, according to the present invention, the means for press-injecting the air for back pressure cleaning is provided in the lower part of the water collecting pipe so that the compressed air is uniformly supplied to each membrane module. This increases the cleaning effect of the membrane module. Also,
By providing the means for sucking the membrane permeated liquid on the upper part of the water collecting pipe to easily remove the air at the time of back pressure cleaning, it is possible to avoid the problem that the permeation flow rate decreases due to the residual air. As a result, the filtration process can be performed with all the membrane modules in the same state, and there is no need to perform chemical cleaning according to the membrane module whose membrane permeation liquid amount has decreased quickly. As a result, the filtration duration of the membrane module becomes longer as a whole, so that the number of times of chemical cleaning can be reduced.

Further, by dividing the membrane module into a plurality of membrane module groups according to the water depth and providing a water collecting pipe in each of the membrane module groups, compressed air is supplied more evenly to each membrane module and Can be easily removed.

[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 10 Backwash Valve 11 Compressor

 ─────────────────────────────────────────────────── ─── 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. A plurality of submerged membrane modules are provided in a treatment tank, each membrane module is connected to a water collecting pipe, and negative suction pressure is applied to the inside of the membrane through the water collecting pipe so as to take out the membrane permeate. In the solid-liquid separation device configured, solid-liquid separation characterized in that a means for sucking the membrane permeated liquid is provided at the upper part of the water collection pipe, and a means for injecting air for back pressure cleaning is provided at the lower part of the water collection pipe. apparatus. 2. The solid-liquid separation device according to claim 1, wherein the membrane module is divided into a plurality of membrane module groups according to water depth, and a water collecting pipe is provided in each membrane module group.