JPWO2011062273A1 - Water purification system and operation method thereof - Google Patents

Abstract

The present invention includes a first water purifier (11) having a filtration membrane (11a), a prefiltration means (10) having a flushing mechanism (12) for flushing the filtration membrane (11a), and the prefiltration means. The present invention relates to a water purification system (1) characterized by comprising post-filtration means (20) comprising a second water purifier (21) provided downstream of (10) and filled with activated carbon (21a). ADVANTAGE OF THE INVENTION According to this invention, it is a compact and simple structure, and can provide the water purifying system which is hard to be polluted even if it wash | cleans, and its operating method.

Description

The present invention relates to a water purification system and an operation method thereof.
This application claims priority on November 20, 2009 based on Japanese Patent Application No. 2009-265361 for which it applied to Japan, and uses the content here.

  Well water may contain various bacteria, viruses, and pollutants. On the other hand, since chlorine is added to the tap water for sterilization, there is little concern that the tap water is contaminated with bacteria, but there is a problem that the flavor of the water is impaired by the odor of calcite.

Therefore, in order to drink well water and tap water more deliciously as drinking water, water purifiers are widely used. This type of water purifier has the function of removing bacteria, viruses, etc. with a filtration membrane such as a hollow fiber membrane after removing the water odor, musty odor, trihalomethane, pollutants, etc. with an adsorbent such as activated carbon. What you have is known.
For example, Patent Document 1 discloses a water purifier having a pretreatment section filled with activated carbon and a filtration section having a filtration membrane provided downstream of the pretreatment section. According to the water purifier, after the raw water is roughly filtered by the pretreatment unit, the raw water is filtered (purified water) by membrane filtration by the filtering unit.

JP 2007-326065 A

However, as described in Patent Document 1, in the case of a water purification apparatus that performs coarse filtration with activated carbon and then membrane filtration with a filtration membrane, most of the solid matter such as pollutants can be removed with activated carbon. Although it is hard to clog and saves the trouble of washing, activated carbon is easily clogged, and the filtration performance tends to deteriorate with use.
Recovery of the filtration performance can be solved by making the activated carbon filled disposable into a cartridge-type container and replacing it as necessary. However, there is a problem that the cost is increased and the replacement takes time.
Moreover, disposable is not always preferable in terms of environmental problems and resource saving.

Moreover, in order to recover the filtration performance, a method of washing (backwashing) by flowing back washing water such as raw water into activated carbon is also known. Backwashing extends the life of activated carbon and reduces costs and replacement times.
However, in order to backwash the activated carbon, it is necessary to add a line or install a line switching means so that the washing water can be supplied and discharged, which tends to be a large scale.

  Further, since the backwashing causes the washing water to flow back to the activated carbon, the raw water inlet and the permeate outlet at the time of filtration and the washing water inlet and the outlet at the time of washing are usually switched. Therefore, for example, when raw water is used as the washing water, the unfiltered washing water (raw water) is supplied to the activated carbon from the permeate outlet at the time of filtration (that is, the side where the raw water is filtered and discharged). The permeated water outlet during filtration and the line connected thereto may be contaminated during backwashing.

  The present invention has been made in view of the above circumstances, and has an object of providing a water purification system and a method for operating the water purification system that have a compact and simple configuration and are less likely to be contaminated even after cleaning.

  The water purification system of the present invention includes a first water purifier provided with a filtration membrane, a prefiltration means having a flushing mechanism for flushing the filtration membrane, and a first filtration device provided downstream of the prefiltration means and filled with activated carbon. And a post-filtration means comprising two water purifiers.

  Moreover, the operation method of the water purification system of the present invention is the operation method of the water purification system, wherein the first water purifier and the second water purifier are passed through the raw water in this order and filtered. And a flushing step of supplying raw water to the water purifier and flushing the filtration membrane.

  ADVANTAGE OF THE INVENTION According to this invention, it is a compact and simple structure, and can provide the water purifying system and its operating method which are not easily polluted even if it wash | cleans.

It is a schematic block diagram which shows an example of the water purification system of this invention. It is a schematic block diagram which shows the other example of the water purification system of this invention. It is a figure which shows flows, such as raw | natural water at the time of a flushing process.

Hereinafter, the present invention will be described in detail.
[Water purification system]
Drawing 1 is a schematic structure figure showing an example of a water purification system of the present invention. The water purification system 1 includes a pre-filtration means 10 having a first water purifier 11 that filters raw water supplied from a water supply and the like, a post-filtration means 20 including a second water purifier 21, and a first water purifier 11. The raw water supply line 30 that supplies raw water to the first water, the first transfer line 40 that transfers the permeated water that has passed through the first water purifier 11 to the second water purifier 21, and the permeated light that has passed through the second water purifier 11. And a second transfer line 50 for transferring water.

The prefiltration means 10 has the 1st water purifier 11 provided with the filtration membrane 11a, and the flushing mechanism 12 which flushes the filtration membrane 11a.
As the filtration membrane 11a, a filtration membrane usually used in a water purification system such as an ultrafiltration membrane, a microfiltration membrane, and a nanofiltration membrane can be used. Of these, an ultrafiltration membrane is preferred.
Examples of the shape of the filtration membrane 11a include a hollow fiber membrane, a flat membrane, a tubular membrane, and a spiral membrane. These are suitable as filtration membranes because they can easily prevent the passage of contaminants (dust) of 0.1 μm or more, bacteria and viruses, but among these, hollow fiber membranes are preferred, for example, cellulose-based, polyolefin-based, polyvinyl It is preferable to use a hollow fiber membrane made of various materials such as alcohol, PMMA (polymethyl methacrylate), and polysulfone. In particular, it is preferable to use a hollow fiber membrane made of a material having high elongation such as polyethylene.
Further, when a hollow fiber membrane is used as the filtration membrane 11a, its pore diameter (filtration accuracy), filtration area, film thickness, outer diameter and the like are not particularly limited, but for example, the pore diameter is 0.01 to 0.1 μm. The filtration area is 0.2 to 10 m ² , the film thickness is 5 to 300 μm, the outer diameter is 20 to 2000 μm, and the porosity is 20 to 90%.

The flushing mechanism 12 includes a washing water discharge line 12a for discharging washing water after flushing the filtration membrane 11a, and an on-off valve 12b installed in the middle of the washing water discharge line 12a.
The washing water discharge line 12 a is connected to the washing water outlet 11 b of the first water purifier 11.
As the on-off valve 12b, a valve normally used in a water purification system such as an electromagnetic valve can be used.
The on-off valve 12b is controlled to open and close based on a control command from a control unit (not shown), and switches between discharge and stop of cleaning water. The on-off valve 12b can be manually opened and closed to switch between discharge and stop of the washing water.

The post filtration means 20 includes a second water purifier 21 provided downstream of the prefiltration means 10 and filled with activated carbon 21a.
As shown in FIG. 1, the inside of the second water purifier 21 is partitioned by two lid materials 21b, and activated carbon 21a is filled between the two lid materials 21b.
The lid 21b has water permeability and is used to remove dust and iron rust when the first water purifier 11 cannot be removed, and to prevent the activated carbon from flowing out. is there. Examples of the lid member 21b include a nonwoven fabric filter, a sintered filter, a metal or plastic net, and the like.
The activated carbon 21a is for removing residual chlorine, a lime odor, a mold odor, a trihalomethane, a metal ion, and the like from the permeated water that passes through the first water purifier 11 of the post-filter means 20. Examples of the activated carbon 21a include adsorbents such as granular activated carbon, powdered activated carbon, and fibrous activated carbon.

The raw water supply line 30 supplies raw water to the first water purifier 11 of the pre-filtration means 10 and is connected to the raw water inlet 11 c of the first water purifier 11.
The raw water supply line 30 is provided with an on-off valve 31 in the middle. Moreover, you may attach the pressure reduction valve 32 as needed as shown in FIG.
As the on-off valve 31, a valve normally used in a water purification system such as an electromagnetic valve can be used. The on-off valve 31 is controlled to open and close based on a control command from a control unit (not shown), and switches between supply and stop of raw water. The on-off valve 31 can be manually opened and closed to switch between supply and stop of raw water.
The pressure reducing valve 32 adjusts the water pressure of the raw water, and is attached particularly when the water pressure of the raw water is high. As the pressure reducing valve 32, a valve normally used in a water purification system can be used.

  The 1st transfer line 40 transfers the permeate which permeate | transmitted the filtration membrane 11a of the 1st water purifier 11 to the 2nd water purifier 21 of the post filtration means 20, and one end is the 1st water purifier 11. The other end is connected to the permeated water inlet 21 c of the second water purifier 21.

The second transfer line 50 transfers permeated water that has passed through the second water purifier 21, and is connected to the permeated water outlet 21 d of the second water purifier 21.
The second transfer line 50 is provided with an on-off valve 51 in the middle.
As the on-off valve 51, a valve normally used in a water purification system such as an electromagnetic valve can be used. The on-off valve 51 is controlled to open and close based on a control command from a control unit (not shown), and switches between permeated water transfer and stop. The on-off valve 51 can be manually opened and closed to switch between permeate transfer and stop.

The water purification system of the present invention is not limited to the one shown in FIG. 1, and for example, as shown in FIG.
In FIG. 2, the same components as those in FIG.

Since residual chlorine is removed from the permeated water that has passed through the second water purifier 21 of the post-filter means 20, it may be recontaminated by bacteria. Further, as described in Patent Document 1, in order to supply a specific amount of permeated water, a water purifier is generally provided with a tank for storing permeated water. Therefore, the permeated water stored in the tank may be contaminated with bacteria.
However, since the water purification system of the present invention uses a filtration membrane having a high processing capacity, it can supply a sufficient amount of permeated water and does not require the installation of a tank for storing the permeated water. Therefore, the permeated water that has passed through the second water purifier 21 of the post-filter means 20 can be directly supplied instead of supplying the permeated water after storing in a tank or the like. Therefore, in the water purification system of the present invention, permeated water can be supplied before being recontaminated, but as shown in FIG. If it is allowed to pass through, it is possible to supply permeated water with less risk of contamination.

The antifouling means 60 shown in FIG. 2 includes a third water purifier 61 having a filtration membrane 61a.
As the filter membrane 61a provided in the third water purifier 61, the same filter membrane 11a as exemplified above in the description of the prefiltration means 10 can be exemplified.
The permeated water passing through the third water purifier 61 of the anti-contamination preventive means 60 is free from dust, bacteria, viruses, etc., so that the filtration membrane 61a is not easily clogged. Therefore, the anti-contamination preventing means 60 does not need to include a flushing mechanism for flushing the filtration membrane 61a.

The other end of the second transfer line 50 is connected to the permeate inlet 61b of the anti-contamination preventing means 60.
On the other hand, a third transfer line 70 is connected to the permeate outlet 61 c of the anti-pollution prevention means 60 so that the permeate that has passed through the third water purifier 61 can be transferred.

In the third transfer line 70, an on-off valve 71 may be set on the way.
As the on-off valve 71, a valve normally used in a water purification system such as an electromagnetic valve can be used. The on-off valve 71 is controlled to open and close based on a control command from a control unit (not shown), and switches between permeated water transfer and stop. The on-off valve 71 can be manually opened and closed to switch between permeated water transfer and stop.
When the on-off valve 71 is installed in the third transfer line 70, it is not necessary to install the on-off valve in the second transfer line as shown in FIG.

The antifouling means 60 is not limited to a water purifier employing a so-called out-in system in which permeated water as shown in FIG. 2 permeates from the outside to the inside of the filtration membrane 61a. You may be comprised from the water purifier which employ | adopted what is called in-out which permeate | transmits from the inner side to the outer side.
Furthermore, as the anti-contamination preventing means 60, for example, an ultraviolet irradiator can be used in addition to the water purifier described above. When using an ultraviolet irradiator, the second transfer line 50 is made of a material that can transmit ultraviolet rays, and the second transfer line 50 can be irradiated with ultraviolet rays through permeated water passing through the second transfer line 50. An ultraviolet irradiator may be provided in the middle of 50.

The water purification system of the present invention is used by connecting a power supply unit (not shown) to an external power supply (such as an outlet), but it is preferable to provide a battery storage unit in the power supply unit so that the battery can be driven.
If the battery can be driven, for example, it is possible to automatically control the opening / closing of each on-off valve even during a power failure.

Further, the water purification system is preferably provided with a switching function for switching the opening / closing of each on-off valve from automatic control to manual control, and an auto function (timer) that can manually start the water purification system and stop the operation automatically. .
In addition, the water purification system has an exchange display function that informs when to replace the filtration membrane and activated carbon, a battery remaining capacity warning function that informs the remaining battery level, and a water pressure warning function that informs you when the water pressure of the raw water has increased significantly. It is preferable to provide it.

  The water purification system of the present invention can be used in any of a wall-mounted type, a stationary type, a faucet direct connection type, an undersink type, etc., but is preferably used in a wall-mounted type in terms of design and space saving. .

[how to drive]
Hereinafter, an example of the operation method of the water purification system of the present invention will be described according to the operation using the water purification system 2 shown in FIG.
In the operation method of the cleaning system of the present invention, the filtration step and the flushing step are repeated.

In the filtration step, the on-off valve 31 and the on-off valve 71 are opened, and the on-off valve 12b is closed.
In the filtration step, the raw water supplied from the raw water supply line 30 is filtered through the first water purifier 11 of the pre-filtration means 10 and the second water purifier 21 of the post-filtration means 20 in this order. At this time, if the water pressure of the raw water in the raw water supply line 30 is high, the amount of raw water supplied to the first water purifier 11 increases, so that the filtration membrane 11a tends to be clogged. When the water pressure is high, the pressure is adjusted by the pressure reducing valve 32 so that the water pressure is about 0.05 to 0.5 MPa. In addition, if the water pressure warning function mentioned above is provided in the water purification system, a warning is given when the water pressure becomes higher than the set value, so that it can be easily recognized that the water pressure has become too high.

The raw water flows in from the raw water inlet 11c of the first water purifier 11, passes through the filtration membrane 11a, becomes permeate, and is discharged from the permeate outlet 11d. When the raw water passes through the permeable membrane 11a, dust, bacteria, viruses and the like are removed. The discharged permeated water passes through the first transfer line 40 and is supplied to the second water purifier 21 of the post-filtration means 20.
The permeate flows in from the permeate inlet 21c of the second water purifier 21, passes through the lid member 21b and the activated carbon 21a, and is discharged from the permeate outlet 21d. When the permeated water passes through the lid member 21b and the activated carbon 21a, residual chlorine, a lime odor, a mold odor, a trihalomethane, a metal ion, and the like are removed. The discharged permeated water passes through the second transfer line 50 and is supplied to the third water purifier 61 of the back pollution prevention means 60.
The permeated water flows in from the permeated water inlet 61b of the third water purifier 61, passes through the filtration membrane 61a, and is discharged from the permeated water outlet 61c. The permeated water permeates the permeable membrane 61a, thereby preventing contamination due to bacterial growth or the like. The discharged permeated water passes through the third transfer line 70 and is supplied as purified water from a water tap (not shown).
In addition, in FIG. 2, the flow of raw | natural water and permeated water is shown by the arrow.

Next, after performing the filtration step for a predetermined time or after filtering a predetermined amount of raw water, the filtration membrane 11a of the first water purifier 11 is flushed (membrane cleaning) as follows.
Here, the flow of raw water or the like during flushing is indicated by arrows in FIG. In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

In the flushing step, the on-off valve 31 and the on-off valve 12b are opened, and the on-off valve 71 is closed.
In the flushing step, as described above, the opening and closing of the on-off valve 12b and the on-off valve 71 is switched, and the raw water is supplied from the raw water supply line 30 to the first water purifier 11 of the pre-filtration means 10 as shown in FIG. The discharge of the permeated water (that is, the filtration of the raw water) is stopped, and the washing water is discharged by flushing the filtration membrane 11a. At this time, when the water pressure of the raw water in the raw water supply line 30 is high, the pressure is adjusted to about 0.05 to 0.5 MPa by the pressure reducing valve 32.

The raw water flows from the raw water inlet 11 c of the first water purifier 11 and passes through the first water purifier 11. At this time, the filtration membrane 11a is flushed, so that dirt or the like attached to the surface of the filtration membrane 11a is washed away by the raw water.
The raw water containing dirt becomes washing water and is discharged from the washing water outlet 11b. The wash water passes through the wash water discharge line 12a and is discharged out of the system.

The flushing time in the flushing step is preferably 10 to 90 seconds. If the flushing time is 10 seconds or more, the filtration membrane 11a of the first water purifier 11 can be sufficiently flushed. On the other hand, if the flushing time is 90 seconds or less, the supply stop time to the water supply place can be shortened and the amount of water used for cleaning can be reduced.
The flushing time can be set by a rotary switch (not shown).

After the flushing process is completed, the process can proceed to the filtration process as it is.
In the operation method of the water purification system of the present invention, the means for controlling the switching from the filtration step to the flushing step (that is, opening and closing of each on-off valve) is not particularly limited, and may be switched manually or in the water purification system. Automatic control means (control unit) may be provided and switched by automatic control. By the automatic control, for example, the flushing process can be performed when the water purification system is activated or at midnight.

As described above, in the water purification system of the present invention, raw water is filtered by the first water purifier provided with a filtration membrane, and then further filtered by the second water purifier filled with activated carbon. Accordingly, most of the dust, bacteria, viruses and the like in the raw water are removed by the first water purifier that filters the raw water first. Therefore, although the filtration membrane provided in the first water purifier is easily clogged with these removed substances (dirt), the dirt is removed by flushing, so that the filtration performance can be easily recovered.
Since flushing requires fewer additional lines than backwashing, the water purification system of the present invention that restores filtration performance by flushing the filtration membrane has a compact and simple configuration.

In addition, as described above, in the backwash, the raw water inlet and the permeate outlet at the time of filtration and the wash water inlet and the outlet at the time of washing are interchanged. Therefore, when backwashing with raw water, raw water is supplied from the permeate outlet (that is, the side where the raw water is filtered and discharged as permeate), and the permeate outlet at the time of filtration and the line connected to it are There was a risk of contamination by backwashing.
However, with the water purification system of the present invention, the filtration performance is recovered by flushing the filtration membrane. During the flushing process, raw water is supplied to the first water purifier from the same inlet (raw water inlet) as in the filtration process, and the wash water is discharged from an outlet (washing water outlet) different from the permeated water outlet. The line through which the permeate passes is not easily contaminated.

  In the water purification system of the present invention, most of the dust, bacteria, viruses and the like in the raw water are removed by the first water purifier. Therefore, the activated carbon of the second water purifier is less likely to be clogged, and the labor of washing can be saved. Moreover, when the back pollution prevention means which consists of a 3rd water purifier provided with the filtration membrane is provided downstream of the post filtration means, the filtration membrane of the 3rd water purifier is not easily clogged, so that the labor of washing can be saved.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
[Example]
The tap water was filtered using the water purification system shown in FIG.
As the first water purifier 11 of the prefiltration means 10 and the third water purifier 61 of the anti-contamination prevention means 60, an ultrafiltration membrane (hollow fiber membrane manufactured by Gambro Co., Ltd., “Polyfiux”, filtration Membrane module having an area: 2.0 m ² , filtration accuracy: 0.01 μm, film thickness: 50 μm, outer diameter: 215 μm) was used.
As the post-filtering means 20, a cylindrical container having a diameter of 7 cm and a length of 20 cm was used, and the inside thereof was partitioned with two nonwoven fabrics, and a water purifier filled with 200 g of granular activated carbon was used therebetween.
As the on-off valves 12b, 31, and 71, solenoid valves (caliber: 3 / 8B, operating voltage: DC12V) were used.

Each on-off valve was switched by automatic control, and conditions for each process were set as shown below.
The supply amount of raw water (tap water) was set to 2 L / min, and the pressure was adjusted by the pressure reducing valve 32 so that the water pressure of the raw water in the raw water supply line 30 was 0.2 MPa.
The flushing time of the flushing process was set to 20 seconds.

And operation of the water purification system was started and raw water was filtered. Then, when the integrated filtration flow rate exceeded 20 L by automatic control and after the filtration operation was completed, the filtration process was switched to the flushing process (that is, the opening / closing of each on-off valve was switched by automatic control). And after flushing the filtration membrane 11a of the 1st water purifier 11, it was made to transfer to the filtration process. This operation was repeated for 240 hours, and tap water was filtered.
As a result, even if the filtration membrane was washed, the filtration process and the flushing process could be repeated without contaminating the system.

ADVANTAGE OF THE INVENTION According to this invention, it is a compact and simple structure, and can provide the water purifying system and its operating method which are not easily polluted even if it wash | cleans.

  1: water purification system, 2: water purification system, 10: pre-filtration means, 11: first water purifier, 11a: filtration membrane, 12: flushing mechanism, 12a: washing water discharge line, 20: post-filtration means, 21: first 2nd water purifier, 21a: activated carbon, 30: raw water supply line, 40: first transfer line, 50: second transfer line, 60: anti-contamination prevention means, 61: third water purifier, 61a: filtration membrane 70: Third transfer line.

Claims (2)

A first water purifier comprising a filtration membrane, and a pre-filtration means having a flushing mechanism for flushing the filtration membrane;
A post-filter means comprising a second water purifier provided downstream of the pre-filter means and filled with activated carbon;
A water purification system characterized by comprising: An operation method of the water purification system according to claim 1,
A filtration step of filtering the raw water through the first water purifier and then the second water purifier,
A flushing step of supplying raw water to the first water purifier and flushing the filtration membrane;
The operation method of the water purification system characterized by repeating.

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