JP2007000712A - Solid-liquid separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-liquid separating device capable of removing fine turbid substance causing the fouling of a membrane from a concentrated liquid. <P>SOLUTION: The device is provided with: a membrane separator 3 installed in a treatment tank 1 into which a turbid substance-containing raw liquid is introduced; and a diffuser 4 arranged at the lower part of the membrane separator 3. The diffuser 4 at least diffuses fine bubbles for the floatation separation of fine turbid substance, and the fine turbid substance causing the fouling of the membrane is removed from the concentrated liquid by floatation separation, thus the stable operation of the membrane separator 3 is continued. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid-liquid separation apparatus, and relates to a solid-liquid separation technique in fields such as industrial waste water, water treatment, or water purification.

  Conventionally, as a solid-liquid separator, there are an immersion type membrane separator and a floating separator. The submerged membrane separation device supplies bubbles below the membrane, and the bubbles rise along the membrane surface, so that the treated water filtered by the membrane separation device is taken out while cleaning the surface of the membrane surface. Since the separated turbidity stays in the concentrate, the turbidity is discharged out of the system by appropriately discharging the concentrated liquid.

  The levitation separator is a device that attaches the turbidity in the stock solution to the bubbles and floats it on the liquid surface to separate it. There is a pressurized levitation method in which, after being pressurized, the pressure is reduced by opening it in the tank under the pressure in the treatment tank, and the gas dissolved in the stock solution is naturally vaporized to generate bubbles.

  Further, in Patent Document 1, a flotation treatment device and a membrane filtration device are arranged in a flotation treatment tank that introduces treated raw water mixed with pressurized water, and a flock that rises to the flotation treatment tank is taken out by the flotation treatment device, The raw water from which the floc has been removed by the treatment device is filtered by the membrane module of the membrane filtration device.

  Further, Patent Document 2 discloses that a membrane module immersed in a treatment tank is caused to eject coarse bubbles through a blower tube different from a blower for a diffuser tube, and to cause the coarse bubbles to collide with the membrane module. It describes what removes the sludge adhering to the module.

In Patent Document 3, a membrane separation device used for the membrane separation and concentration method is installed in a sludge separation and concentration tank, and an aeration device for membrane cleaning is installed below the membrane separation device. There is a description that the membrane of the separation device is washed, and at the same time, the sludge floc deposited on the membrane is given buoyancy and accumulated above the separation and concentration tank.
JP-A-7-214047 JP 11-314025 A Japanese Patent Laid-Open No. 10-128400

  By the way, in order to suppress membrane fouling in the submerged membrane separator, it is necessary to reduce as much as possible the fine turbidity that greatly contributes to membrane fouling. However, for that purpose, it is necessary to increase the discharge amount of the concentrated solution, and the recovery rate (membrane treatment solution / stock solution inflow amount) decreases.

  Further, in order to effectively discharge coarse turbidity accumulated at the bottom of the tank, the concentrated liquid discharging means (pipe) is usually provided at the bottom of the tank. However, since the fine turbidity that greatly contributes to the fouling of the membrane is uniformly diffused in the concentrated liquid, it cannot be said that it can be effectively discharged by the discharge means provided at the bottom of the tank. For this reason, the finer turbidity in the tank becomes a higher concentration factor, which causes the membrane to foul.

On the other hand, the flotation separator can concentrate turbidity to a very high concentration, but it is unavoidable that some turbidity remains in the separation liquid, and there is a limit in improving the quality of treated water. .
In what is described in Patent Document 1, since the levitation treatment device is arranged at the upper position of the levitation treatment tank and the membrane filtration device is arranged at the lower position, the levitation treatment becomes a transient treatment, and the levitation treatment cannot be completed. Since the suspended matter that has flowed down to the bottom of the levitation treatment tank continues to be concentrated without being levitated and separated, the cause of the progress of membrane fouling cannot be excluded.

  Although what is described in Patent Document 2 can cause coarse bubbles to collide with the membrane module and remove sludge adhering to the membrane module, turbidity that is a fine turbidity that greatly contributes to membrane fouling is obtained. It cannot be floated and separated, and the cause of the progress of membrane fouling cannot be excluded.

  Patent Document 3 describes that the membrane of the membrane separator can be washed with bubbles from the air diffuser, and at the same time, the sludge floc deposited on the membrane can be given buoyancy and accumulated above the separation and concentration tank. However, the fine turbidity that diffuses uniformly in the concentrated liquid and greatly contributes to the fouling of the membrane cannot be floated and separated, and the cause of the progress of the fouling of the membrane cannot be excluded.

  This invention solves the above-mentioned subject, and it aims at providing the solid-liquid separation apparatus which can remove the fine turbidity which causes the fouling of a film | membrane from a concentrate.

  In order to solve the above problems, a solid-liquid separation device according to a first aspect of the present invention includes a membrane separation device installed in a treatment tank for introducing a stock solution containing turbidity, and an air diffuser disposed below the membrane separation device. The air diffuser diffuses at least fine air bubbles for floating separation of fine turbidity.

  With the configuration described above, the fine turbidity in the stock solution can be floated and separated by the fine bubbles diffused from the diffuser, and collected and concentrated in the upper area of the treatment tank. The concentrated fine turbidity is located above the treatment tank. It is discharged out of the tank by discharge means such as an overflow pipe or scraper placed in the area.

  On the other hand, the membrane separation apparatus concentrates the stock solution by solid-liquid separation of the stock solution and taking out the membrane filtrate as treated water. At this time, since the fine turbidity causing the fouling of the membrane is removed from the concentrated liquid by floating separation, it is possible to continue the stable operation of the membrane separation apparatus.

  The solid-liquid separation device of the second invention includes a membrane separation device installed in a treatment tank for introducing a stock solution containing turbidity, and an aeration device arranged below the membrane separation device, and the diffusion device is fine. It consists of a fine bubble diffusing device for diffusing fine bubbles for turbid floating separation and a coarse bubble diffusing device for diffusing coarse bubbles for membrane surface cleaning.

  With the configuration described above, the fine turbidity in the stock solution can be floated and separated by the fine bubbles diffused from the fine bubble diffusing device, and collected and concentrated in the upper area of the treatment tank. It is discharged out of the tank by discharge means such as an overflow pipe and a scraper disposed in the upper area of the tank.

  On the other hand, the membrane separation apparatus concentrates the stock solution by solid-liquid separation of the stock solution and taking out the membrane filtrate as treated water. At this time, the separated solid matter adhering to the membrane surface is washed with coarse bubbles for membrane surface cleaning diffused from the coarse bubble diffuser, and the fine turbidity causing membrane fouling is separated from the concentrate by floating separation. Since it is removed, stable operation of the membrane separation apparatus can be continued. The fine bubble diffuser and the coarse bubble diffuser can be operated at the same time, or can be operated alternately.

  A solid-liquid separation device according to a third aspect of the present invention is disposed in a treatment tank for introducing a stock solution containing turbidity, and disposed below the membrane separation device to diffuse coarse bubbles for membrane surface cleaning. The apparatus includes a coarse bubble diffusing device and a fine bubble diffusing device that is disposed at a position outside the lower region of the membrane separation device and diffuses fine bubbles for floating separation of fine turbidity.

  With the configuration described above, the fine turbidity in the stock solution can be floated and separated by the fine bubbles diffused from the fine bubble diffusing device, and collected and concentrated in the upper area of the treatment tank. It is discharged out of the tank by discharge means such as an overflow pipe and a scraper disposed in the upper area of the tank.

  On the other hand, the membrane separation apparatus concentrates the stock solution by solid-liquid separation of the stock solution and taking out the membrane filtrate as treated water. At this time, the separated solid matter adhering to the membrane surface is washed with coarse bubbles for membrane surface cleaning diffused from the coarse bubble diffuser, and the fine turbidity causing membrane fouling is separated from the concentrate by floating separation. Since it is removed, stable operation of the membrane separation apparatus can be continued.

Since the fine bubble diffusing device and the coarse bubble diffusing device are arranged at different positions, they do not interfere with each other, and can be operated simultaneously or alternately.
In addition, ascending flow is generated in the tank due to coarse bubbles, downflow is generated in other parts of the tank, and the contact efficiency between the fine turbidity and the fine bubbles is increased by facing the downflow and the fine bubbles. The efficiency of flotation separation is improved.

  A solid-liquid separation device according to a fourth aspect of the present invention is a membrane separation device installed in a treatment tank for introducing a stock solution containing turbidity, and a stock solution for supplying a stock solution in which air is dissolved by applying pressure under the membrane separation device Pressure supply means.

  With the configuration described above, the stock solution supplied into the treatment tank in a pressurized state by the stock solution pressurizing and supplying means is decompressed by being released under pressure in the treatment tank to generate fine bubbles, and the generated fine bubbles cause The fine turbidity can be separated by floating and collected in the upper area of the treatment tank and concentrated. The concentrated fine turbidity is discharged out of the tank by discharge means such as an overflow pipe or a scraper disposed in the upper area of the treatment tank.

  On the other hand, the membrane separation apparatus concentrates the stock solution by solid-liquid separation of the stock solution and taking out the membrane filtrate as treated water. At this time, since the fine turbidity causing the fouling of the membrane is removed from the concentrated liquid by floating separation, it is possible to continue the stable operation of the membrane separation apparatus.

  A solid-liquid separation device according to a fifth aspect of the present invention is disposed in a treatment tank for introducing a stock solution containing turbidity, and disposed below the membrane separation device to diffuse coarse bubbles for membrane surface cleaning. A coarse bubble diffusing device and a stock solution pressurizing supply means for supplying a stock solution pressurized and dissolved in air below the membrane separation device.

  With the configuration described above, the stock solution supplied into the treatment tank in a pressurized state by the stock solution pressure supply means is released under the pressure in the treatment tank, and fine bubbles are generated by the reduced pressure, so that the fine turbidity is formed by the fine bubbles. It can be floated and separated and collected in the upper area of the treatment tank and concentrated. The concentrated fine turbidity is discharged out of the tank by discharge means such as an overflow pipe or a scraper disposed in the upper area of the treatment tank.

  On the other hand, the stock solution is solid-liquid separated by a membrane separator and the membrane filtrate is taken out as treated water to concentrate the stock solution. At this time, the separated solid matter adhering to the membrane surface is washed with coarse bubbles for membrane surface cleaning diffused from the coarse bubble diffuser, and the fine turbidity that causes membrane fouling is separated from the concentrate by floating separation. Since it is removed, stable operation of the membrane separation apparatus can be continued.

  The solid-liquid separation device according to the sixth aspect of the present invention is arranged in a treatment tank for introducing a stock solution containing turbidity, and disposed below the membrane separation device, and diffuses coarse bubbles for membrane surface cleaning. A coarse bubble diffusing device and a stock solution pressurizing and supplying means for supplying a stock solution in which air is dissolved by pressurization are provided at a position outside the lower region of the membrane separation device.

  With the configuration described above, the stock solution supplied into the treatment tank in a pressurized state by the stock solution pressurizing and supplying means is decompressed by being released under the pressure in the treatment tank to produce fine bubbles, and the stock solution is generated by the generated fine bubbles. Fine turbidity inside can be floated and separated and collected in the upper area of the treatment tank and concentrated. The concentrated fine turbidity is discharged out of the tank by discharge means such as an overflow pipe or a scraper disposed in the upper area of the treatment tank.

  On the other hand, the membrane separation apparatus concentrates the stock solution by solid-liquid separation of the stock solution and taking out the membrane filtrate as treated water. At this time, the separated solid matter adhering to the membrane surface is washed with coarse bubbles for membrane surface cleaning diffused from the coarse bubble diffuser, and the fine turbidity causing membrane fouling is separated from the concentrate by floating separation. Since it is removed, stable operation of the membrane separation apparatus can be continued. Since the stock solution pressure supply means and the coarse bubble diffusing device are arranged at different positions, they do not interfere with each other.

  In addition, an upward flow is generated in the tank due to coarse bubbles, and a downward flow is generated in other parts of the tank, and the contact efficiency between the fine turbidity and the fine bubbles is increased by facing the downward flow and the fine bubbles. The efficiency of flotation separation is improved.

  As described above, according to the present invention, the fine turbidity is concentrated and discharged to the upper region of the treatment tank by the floating separation by the fine bubbles, and the membrane is separated from the fine turbidity by the solid-liquid separation by the membrane separation device. Thus, stable operation of the membrane separation apparatus can be continued without causing fouling.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, a stock solution supply system 2 for introducing a stock solution containing turbidity is connected to a processing tank 1, and a membrane separation device 3 is installed inside the processing tank 1. The membrane separation device 3 can be of any shape and material such as a ceramic membrane, an organic membrane, a flat membrane, a tubular membrane, and a hollow fiber membrane.

  A diffuser 4 is disposed below the membrane separator 3, and a blower 5 is connected to the diffuser 4. This air diffuser 4 diffuses at least fine air bubbles for floating separation of fine turbidity, and it is possible to mix a fine air bubble hole and a coarse air bubble hole in one air diffuser. It is also possible to separately provide an air diffuser provided with a use hole and an air diffuser provided with a coarse bubble hole.

  In the upper area of the processing tank 1, a scraping device 6 that serves as a discharging means for discharging fine turbidity is provided, and a concentrated liquid discharge system 7 communicates with the lower part of the processing tank 1. A treated water extraction system 9 having a suction pump 8 is connected to the membrane separation device 3.

  With the configuration described above, the fine bubbles diffused from the diffuser 4 rise with turbidity in the stock solution, float and separate the fine turbidity from the stock solution, and collect the fine turbidity in the upper area of the treatment tank 1. To concentrate. The concentrated fine turbidity is discharged out of the tank by the scraping device 6.

  On the other hand, the stock solution is solid-liquid separated by the membrane separation device 3 by driving the suction pump 8, the membrane filtrate is taken out from the treated water extraction system 9 as treated water and concentrated, and the concentrated solution is appropriately passed through the concentrated solution discharge system 7. To discharge. Therefore, since the fine turbidity that causes the fouling of the membrane of the membrane separation device 3 is removed from the concentrate by floating separation, it is possible to continue the stable operation of the membrane separation device 3.

  It is also possible to provide a means for injecting a flocculant into the treatment tank 1 and also perform the aggregating action of incorporating a soluble fouling substance such as chromaticity into the floc by the flocculant. This aggregating action can be performed in other embodiments described below.

  As shown in FIG. 2, the air diffuser 4 includes a fine bubble diffuser 4 a that diffuses fine bubbles for floating separation of fine turbidity, and a coarse bubble diffuser that diffuses coarse bubbles for cleaning the membrane surface. 4b, and blowers 5a and 5b are connected to each.

  In this configuration, the separated solid matter adhering to the membrane surface of the membrane separation device 3 is diffused from the fine bubble diffusing device 4a while being washed by the membrane surface cleaning coarse bubbles diffused from the coarse bubble diffusing device 4b. It is possible to continue the stable operation of the membrane separation device 3 by floating and separating the fine turbidity by the fine bubbles for floating separation.

The fine bubble diffusing device 4a and the coarse bubble diffusing device 4b can be operated simultaneously, or can be operated alternately.
As shown in FIG. 3, the diffuser 4 includes a fine bubble diffuser 4 a that diffuses fine bubbles for floating separation of fine turbidity, and a coarse bubble diffuser that diffuses coarse bubbles for cleaning the membrane surface. 4b, blowers 5a and 5b are connected to each other, and the fine bubble diffusing device 4a can be disposed at a position outside the lower region of the membrane separation device 3.

  In this configuration, the separated solid matter adhering to the membrane surface of the membrane separation device 3 is diffused from the fine bubble diffusing device 4a while being washed by the membrane surface cleaning coarse bubbles diffused from the coarse bubble diffusing device 4b. It is possible to continue the stable operation of the membrane separation device 3 by floating and separating the fine turbidity by the fine bubbles for floating separation. Further, since the fine bubble diffusing device 4a and the coarse bubble diffusing device 4b are arranged at different positions, they do not interfere with each other and can be operated simultaneously or alternately. is there.

  In addition, an upward flow is generated in the tank due to coarse bubbles, and a downward flow is generated in other parts of the tank, and the contact efficiency between the fine turbidity and the fine bubbles is increased by facing the downward flow and the fine bubbles. The efficiency of flotation separation is improved.

  FIG. 4 shows another embodiment of the present invention, in which a stock solution supply system 2 is connected to the lower side of the membrane separation device 3, and a stock solution in which air is dissolved by pressurization is supplied to the stock solution supply system 2. A stock solution pressurizing pump 10 is provided as a stock solution supply means.

  With the above-described configuration, the stock solution pressurized and supplied by the stock solution pressurizing pump 10 is released under the pressure in the treatment tank after the compressed air supplied by the compressor or the like is pressurized and dissolved in the pressurization tank 11 and then decompressed. Produces fine bubbles. Fine turbidity in the stock solution is floated and separated by the fine bubbles, and collected in the upper area of the processing tank 1 and concentrated. The concentrated fine turbidity is discharged out of the tank by the scraping device 6. Therefore, the stable operation of the membrane separation device 3 can be continued by removing the fine turbidity that causes membrane fouling from the concentrate by flotation separation.

  The stock solution supply system 2 equipped with the stock solution pressurizing pump 10 can be connected to the lower side of the membrane separation device 3 or can be connected to a position outside the lower region of the membrane separation device 3. Fine bubbles for separation and coarse bubbles for membrane cleaning do not interfere with each other.

  Further, when the stock solution supply system 2 including the stock solution pressurizing pump 10 is located at a position deviating from the lower region of the membrane separation device 3, the downflow caused by the coarse bubbles and the fine bubbles face each other, so that the fine turbidity The contact efficiency between the air quality and the fine bubbles is increased, and the efficiency of floating separation is improved.

The schematic diagram which shows the solid-liquid separator in embodiment of this invention The schematic diagram which shows the solid-liquid separation apparatus in other embodiment of this invention. The schematic diagram which shows the solid-liquid separation apparatus in other embodiment of this invention. The schematic diagram which shows the solid-liquid separation apparatus in other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Treatment tank 2 Stock solution supply system 3 Membrane separation device 4 Aeration device 5 Blower 6 Scraping device 7 Concentrated liquid discharge system 8 Suction pump 9 Treated water extraction system 10 Stock solution pressurization pump

Claims (6)

A membrane separation device installed in a treatment tank for introducing a stock solution containing turbidity, and an aeration device arranged below the membrane separation device, wherein the aeration device has at least fine bubbles for floating separation of fine turbidity. A solid-liquid separator characterized by aeration. A membrane separation device installed in a treatment tank into which a stock solution containing turbidity is introduced, and an aeration device arranged below the membrane separation device, which diffuses fine bubbles for floating separation of fine turbidity. A solid-liquid separation device comprising: a fine bubble diffusing device to be circulated; and a coarse bubble diffusing device for diffusing coarse bubbles for membrane surface cleaning. A membrane separator installed in a treatment tank for introducing a stock solution containing turbidity, a coarse bubble diffuser arranged below the membrane separator to diffuse coarse bubbles for cleaning the membrane surface, and a membrane separator A solid-liquid separation device, comprising: a fine bubble diffusing device that is disposed at a position outside the lower region and diffuses fine bubbles for floating separation of fine turbidity. A membrane separation device installed in a treatment tank for introducing a stock solution containing turbidity, and a stock solution supply means for supplying a stock solution in which air is dissolved by pressurization is provided below the membrane separation device. Solid-liquid separator. A membrane separator installed in a treatment tank for introducing a stock solution containing turbidity, a coarse bubble diffuser arranged below the membrane separator to diffuse coarse bubbles for cleaning the membrane surface, and a membrane separator A solid-liquid separation device comprising: a stock solution pressurizing supply means for supplying a stock solution in which air is dissolved by pressurization. A membrane separator installed in a treatment tank for introducing a stock solution containing turbidity, a coarse bubble diffuser arranged below the membrane separator to diffuse coarse bubbles for cleaning the membrane surface, and a membrane separator A solid-liquid separation device comprising: a stock solution pressurizing supply means for supplying a stock solution in which air is dissolved by pressurization at a position deviating from a lower region.

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