JP2000210508A - Water treatment facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a treatment efficient while an installing space of a whole water treatment facility and a cost are reduced by enabling a continuous filter device to be appropriately used by a method wherein the continuous filter device is connected to a previous step of a membrane treatment device, and a raw water feed amount to the continuous filter device is controlled according to a flow rate of the membrane treatment device. SOLUTION: Raw water is fed to a continuous filter device 101 via a flow rate control valve 105 with a raw water feed pump 104, and treated by filtering. The treated filtered water, after being stored in a filtered water receiving tank 103 via an overflow weir 106, is fed to a membrane treatment device 102 with a filtered water pump 107. Further, a part of the filtered water is fed to a washing apparatus 8 of the filter device 101 as washing water. Further, a water level detector 108 is arranged to the filtered water receiving tank 103, and a detected water level signal is transmitted to a controller 109. Then the controller 109 controls feed amount of raw water in order to secure a water storing amount in the filtered water receiving tank 103 so that a prescribed flow rate of the treated water is fed to the membrane treatment device 102 by the filtered water pump 107.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filtration device as a pretreatment device at the front stage, an ultrafiltration device (hereinafter sometimes abbreviated as UF device) and a reverse osmosis membrane device (hereinafter R) at the rear stage.
O device may be abbreviated. The present invention relates to a water treatment device having a precision treatment device such as

[0002]

2. Description of the Related Art Conventionally, water to be treated to be supplied to a UF device or an RO device is obtained by treating coagulated sediment water such as industrial water or river water with a pressure filtration device or a gravity filtration device. General. In the case of the RO device, an activated carbon, a polishing filter, or other fine filtration means may be interposed as necessary.

[0003] Such a conventional water treatment apparatus is usually configured in a system as shown in Fig. 6, for example. Raw water is sent by a pump 501 or the like to a fixed-bed filtration device 502 composed of a pressure filtration device or a gravity filtration device, and the filtered water is processed by a membrane treatment device 503 composed of a UF device, an RO device, or the like. To obtain treated water. For example, when the pressure treatment device and the UF device are communicated with each other when the membrane processing device 503 is a UF device, the backwash of the filtration device must be performed with UF treated water. In addition, since there is a problem that the recovery rate of the treated water from the UF device is reduced, it is usually necessary to install a filtrate water storage tank 504 between the filtration device 502 and the UF device (membrane treatment device) 503. From the filtered water storage tank 504, the filtered water pump 50
5, the water to be treated is supplied to the membrane treatment device 503, and at the time of back washing, the operation of the filtration device 502 is stopped while the supply to the membrane treatment device 503 is continued, and the back washing pump 506 backwashes the filtration device 502. Supply water and drain water after washing.

[0004] The filtered water storage tank 504 includes a filtering device 502.
It is necessary to hold the total water amount of the backwashing water amount and the UF raw water amount during backwashing. When the filtration device 502 is a general sand filtration device, the filtered water storage tank 504 is used for one hour. It was necessary to have a capacity capable of securing a certain residence time. Therefore, the size of the filtered water storage tank 504 becomes large,
There has been a problem that the installation space and cost, and eventually the installation space and cost of the entire system, increase.
Similarly, when the filtration device 502 is a gravity filtration device, a large filtered water storage tank is required.

[0005] Even when the membrane treatment device 503 comprises an RO device, if the pressure type filtration device and the RO device are communicated, there is a problem that the recovery rate of the treated water decreases as in the case of the UF. Again, it is necessary to install a filtered water storage tank in the middle. Also, if RO is stopped during backwashing of the filtration device, RO
Precipitates are generated on the reject side of the device and bubbles are generated, making it difficult to operate stably. Therefore, it is necessary to install a filtered water storage tank at the subsequent stage of the filtration device from this aspect, and to supply backwash water and RO. In order to secure the amount of water to be treated, a large filtered water storage tank is also required.

In particular, when raw water of high turbidity is supplied,
Since the frequency of backwashing of the fixed-bed type filtration device increases, it is necessary to further increase the capacity of the filtration water storage tank provided in the middle or to reduce the frequency of backwashing by installing a coagulation sedimentation facility further in the previous stage. . In addition, since UF and RO devices dislike flow rate fluctuations, that is, if the flow rate is too high, blockage occurs, and if the flow rate is too low, the efficiency of treatment is reduced. However, a relatively large capacity is required for the filtered water storage tank from the viewpoint of stably securing a desired flow rate even during the backwashing of the filtration device.

On the other hand, a continuous filtration device is known as a filtration device which does not require stopping the filtration operation for backwashing. Among them, Japanese Patent Publication No. 3-27242 and Japanese Patent Publication No. 56
JP-A-51808 describes a method of continuously extracting a filter medium from a lower portion of a filter bed, washing the filter medium, returning the filter medium to the surface side of the filter bed, and passing raw water through the filter bed in an upward flow to treat water (filtered water). Can be obtained completely continuously by using a filter device of the type that obtains from the overflow weir above, and the device can be configured relatively simply.

[0008] In such a continuous filtration apparatus, backwashing is not necessary, and at first glance, a continuous filtration apparatus is installed in place of the fixed-bed filtration apparatus 502 and the filtered water storage tank 504 in the system shown in FIG. Seems as possible. However, the fixed bed filtration device 502 and the filtered water storage tank 50
Simply installing a conventional continuous filtration device instead of 4 causes the following problems, and in practice, it was difficult to substitute.

That is, as described above, it is desired that a membrane treatment apparatus such as a UF or RO be passed water at a predetermined constant flow rate.
In the continuous filtration device as described above, since the amount of filtered water (treated water) after passing through the filter bed fluctuates due to the fluctuation of the pressure difference of the filter bed, the supply amount of the water to be treated to the membrane treatment device is kept constant. Difficult to keep.

Further, in the continuous filtration apparatus as described above, the treated water after passing through the filter bed is once released to the atmosphere to discharge the overflowed treated water, so that a pump is provided on the treated water side. When directly connected, a problem of air entrapment occurs. Therefore, in practice, it was not possible to adopt a configuration in which water is supplied to the membrane processing apparatus simply by a directly connected pump.

Further, in the continuous filtration apparatus as described above, a part of the filter medium is continuously circulated from the lower part of the filter bed to the surface side of the filter bed, and accordingly, the filter medium in the filter bed sequentially moves downward. However, since a dead space is likely to be formed in the moving bed type filter bed and it is difficult to completely clean the circulating filter medium, a surface cake layer such as SS is formed and the filtration accuracy is relatively high. It was difficult to obtain high treated water quality compared to a fixed-bed type water treatment apparatus that can be maintained. Therefore, particularly when the turbidity of the raw water is high, it has been difficult to simply replace the fixed bed type filtration device with the continuous type filtration device.

[0012]

The problem to be solved by the present invention is shown in FIG.
In addition to paying attention to the problems in the conventional water treatment apparatus as shown in the above, and paying attention to the advantage of the continuous filtration apparatus that does not require backwashing, a continuous filtration apparatus is provided as a filtration apparatus provided in the preceding stage of the membrane treatment apparatus. It is possible to reduce the installation space and cost of the entire water treatment apparatus and to improve the efficiency of the treatment by making the apparatus usable without causing a problem.

[0013]

In order to solve the above-mentioned problems, a water treatment apparatus according to the present invention has a continuous filtration device connected to a preceding stage of a membrane treatment device and a continuous filtration device according to a flow rate of the membrane treatment device. It is characterized by having means for controlling the supply amount of raw water to the filtration device.

Various modes can be adopted as means for controlling the supply amount of raw water to the continuous filtration device according to the flow rate of the membrane treatment device. For example, a mode in which the raw water supply amount control means has a buffer tank provided between the continuous filtration device and the membrane treatment device can be adopted. In this buffer tank,
The filtered water filtered by the continuous filtration device is temporarily stored, but the continuous filtration device does not require backwashing, and the continuous filtration is performed so that a desired constant supply amount to the membrane processing device side can be secured. Since the supply amount of raw water to the continuous filtration device is controlled so that the amount of drainage of filtered water from the filtration device does not become too small or too large, the capacity of the buffer tank can be small. In particular, if the water level detecting means is provided in the buffer tank and the supply amount of the raw water is controlled based on the detected water level, the capacity of the buffer tank can be minimized.

Further, it is possible to directly detect the level of the treated water in the continuous filtration device without providing a separate buffer tank, and to control the supply amount of the raw water based on the detected water level. It is.

Further, the raw water supply amount control means is configured to have a flow rate detection means provided between the continuous filtration device and the membrane treatment device, and the flow rate detected between these means (that is, the membrane treatment device) It is also possible to directly control the supply amount of raw water to the continuous filtration device based on the supply flow rate to the continuous filtration device.

The control of the raw water supply amount control means in the raw water supply system to the continuous filtration device can be easily performed by, for example, providing a flow control valve in the raw water supply system. What is necessary is just to control this flow control valve based on the signal from the above-mentioned water level detection means and flow rate detection means.

When the turbidity of the raw water is low, a continuous filtration device is disclosed in Japanese Patent Publication No. 3-27242 or Japanese Patent Publication No.
Although it is possible to use the apparatus as disclosed in JP-A-51808 as it is, in order to supply filtered water that has been more precisely filtered to the membrane treatment apparatus, a continuous apparatus obtained by improving these apparatuses is used. It is preferred to use a type filtration device.

Such an improved continuous filtration device is:
Specifically, for example, it can be configured as follows. In other words, the continuous filtration device is a filter bed of granular filter material, a means for supplying raw water to the lower part of the filter bed, a means for discharging treated water filtered by the filter bed from above the filter bed, and a filter medium at the lower part of the filter bed. A means comprising a means for extracting and transferring to the filter bed surface, a means for cleaning the transferred filter medium, and a control means for intermittently stopping the transfer of the filter medium, or Means for supplying raw water to the filter bed of the filter medium, lower part of the filter bed, means for discharging treated water filtered by the filter bed from above the filter bed, means for extracting the filter medium at the lower part of the filter bed and transferring it to the surface of the filter bed Means for washing the filter medium to be transferred, means for detecting the pressure difference of the filter bed, and the transfer amount of the filter medium in the filter medium transfer means such that the detected pressure difference becomes a preset target value. And a controlling means.

As the membrane treatment device, a known ultrafiltration device or a reverse osmosis membrane device can be used.

In the water treatment apparatus according to the present invention as described above, in the water treatment apparatus having the system configuration having the membrane treatment apparatus, the continuous filtration apparatus is used in the preceding stage, so that it is not necessary to backwash the filtration apparatus. In addition, since there is no need to secure a sufficient amount of water for backwashing, it is not necessary to provide a large-capacity filtered water storage tank as in the related art. As the flow rate of the membrane processing apparatus, a continuous desired constant flow rate is required, and the supply amount of raw water to the continuous filtration apparatus is controlled so that the desired flow rate is always secured. Therefore, the flow rate of the raw water to the continuous filtration device may fluctuate, but the flow rate of the membrane processing device is always controlled to a desired flow rate, and the flow rate between the continuous filtration device and the membrane processing device is changed. Large capacity storage is not required. For example, in the case of a buffer tank installation method,
What is necessary is just to have a capacity enough to secure a residence time of about 1 to 5 minutes, and a conventional large-capacity filtered water storage tank (for example,
The installation space and cost of the buffer tank, as well as the installation space and cost of the entire apparatus, are greatly reduced as compared with the case where a storage capacity of about one hour is installed.

By using the improved filtration device as described above as a continuous filtration device, the quality of filtered water can be greatly improved as compared with a conventional continuous filtration device. A small and inexpensive water treatment apparatus that can maintain the quality of water sufficiently high and can be sufficiently used practically is realized.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a water treatment apparatus according to a first embodiment of the present invention. The water treatment device 100 includes a continuous filtration device 101 in the first stage, and a U
It has a membrane processing apparatus 102 composed of an F apparatus and an RO apparatus, and has a filtered water receiving tank 103 as a buffer tank having a relatively small capacity between them, and these are connected in series. The continuous filtration device 101 can be composed of, for example, the continuous filtration device 1 shown in FIG. 2 and the continuous filtration device 21 shown in FIG. 3, and the continuous filtration device 101 in FIG.
Is shown in a mode using the continuous filtration device 1 shown in FIG.

First, a continuous filtration device suitable for the water treatment device of the present invention will be described. In the water treatment apparatus of the present invention, when the turbidity of the raw water is relatively low and the turbidity is stable in the low state, it is disclosed in Japanese Patent Publication No. 3-27242 and Japanese Patent Publication No. 56-51808. Although it is possible to use such a filtration device as it is, the turbidity of raw water generally fluctuates, and it is often impossible to always supply a low turbidity. In order to stably obtain filtered water, it is preferable to adopt an improved configuration as shown in FIGS.

FIG. 2 shows a case where a continuous filtration device similar to that disclosed in Japanese Patent Publication No. 3-27242 is improved. In FIG. 2, reference numeral 1 denotes an entire continuous filtration apparatus, in which a filter bed 3 of granular filter material, for example, filter sand having a predetermined particle size is formed in a tower 2. Raw water is
The raw water is supplied to a raw water flow path 4 extending vertically along the side wall of the tower 2, and is supplied to a lower part of the filter bed 3 from a supply pipe 5 provided at a lower part of the raw water flow path 4. The supplied raw water passes through the filter bed 3 in an upward flow and is filtered, and is discharged as treated water (filtrated water) from above the filter bed 3 through a treated water outlet 6.

In the raw water flow path 4, there is provided a filter medium transfer pipe 7 extending to the lower end of the filter bed 3 and opening at the lower end.
The filter medium transfer pipe 7 extends to above the tower 2 and communicates with a washing device 8. The washing device 8 returns the washed filter medium to the surface (upper surface) of the filter bed 3 via the return path 9. The filter medium transfer pipe 7 draws out the filter medium at the lower end of the filter bed 3 and removes the filter medium.
In this embodiment, an air lift pump mechanism is used for this transfer, and the filter medium transfer pipe 7 is connected from the air supply pipe 10.
The filter medium is transferred by the air supplied to the inside. The supply of air is controlled by the solenoid valve 11.

In the washing device 8, the separated filter medium is lifted obliquely upward by stirring and separating the transferred filter medium and turbid substances such as SS adhering to the filter medium by rotating the screw 12. It is returned to the surface of the filter bed 3 via the return path 9. At this time, cleaning water is supplied from the cleaning water supply pipe 13 through the nozzle 14, and the separated turbidity is washed out and discharged from the drain pipe 15 as cleaning wastewater. The supply of cleaning water is controlled by a solenoid valve 16. As this cleaning water, a part of the treated water from the treated water outlet 6 can be used, or water from another supply source can be used.

The filter medium is extracted from the lower part of the filter bed 3 and the transfer operation of returning the washed filter medium to the surface of the filter bed 3 is repeated, so that the filter medium in the filter medium filter bed 3 is sequentially moved downward. Is done.

In the vicinity of the raw water supply pipe 5 of the tower 2, a pressure for detecting a pressure difference when the raw water passes through the filter bed 3, that is, a pressure corresponding to an increase in the pressure loss of the filter bed 3 with respect to the initial pressure. A sensor 17 is provided. The differential pressure detection signal from the pressure sensor 17 is sent to the control device 18. Control device 18
Outputs an operation signal to the electromagnetic valve 11 for controlling the supply of air and the electromagnetic valve 16 for controlling the supply of the cleaning water, and controls the supply stop and the supply start thereof.

In this embodiment, the tower 2 is the same as that shown in FIG.
The filter medium transfer pipe 7, the air supply pipe 10, and the cleaning device 8 are horizontally moved by the driving means (not shown). It is configured to be able to reciprocate (in a vertical direction).

FIG. 3 shows a continuous filtration apparatus 21 according to another embodiment, in which a continuous filtration apparatus similar to that disclosed in JP-B-56-51808 is improved. Is shown. In FIG. 3, a filter bed 23 of a granular filter medium is formed in a tower 22, and raw water is supplied to a lower part of the filter bed 23 from a raw water flow path 24. The supplied raw water passes through the filter bed 23 in an upward flow, is filtered, and is discharged from above the filter bed 23 as treated water (filtrated water) through a treated water outlet 25.

At the center of the tower 22, a filter bed 2 is vertically arranged.
A filter medium transfer pipe 26 extending to the lower end of the filter medium 3 is provided, and an upper end of the filter medium transfer pipe 26 communicates with a washing device 27. The filter medium transfer pipe 26 extracts the filter medium at the lower end of the filter bed 23 and transfers it to the washing device 27. In this embodiment, an air lift pump mechanism is used for this transfer, and the air supply pipe 2
The filter medium is transferred by the air supplied from 8 into the filter medium transfer pipe 26. The supply of air is controlled by a solenoid valve 29.

The washing device 27 is provided with an inner tube 30 and an outer tube 31. The inner tube 30 transfers the filter medium by inverting the flow direction of the filter medium ejected from the upper end opening of the filter medium transfer pipe 26. The obtained filter medium and turbid substances such as SS adhering to the filter medium are transferred into the outer tube 31 while being stirred and separated. In the outer tube 31, the separated filter medium having a large specific gravity sinks downward, and the turbid matter having a small specific gravity floats up and is discharged from the drain port 32 as washing wastewater together with washing water. Washing,
The separated filter medium is returned to the surface side of the filter bed 23. In the present embodiment, a part of the treated water that has passed through the filter bed 23 is used as washing water for washing the transferred filter medium. The transfer operation of extracting the filter medium from the lower portion of the filter bed 23 and returning the washed filter medium to the surface of the filter bed 23 is repeated, so that the filter medium 23 to be transferred is separated.
The inner filter media is sequentially moved downward.

In the vicinity of the connecting portion of the raw water flow path 24 of the tower 22,
A pressure sensor 33 that detects a pressure difference when the raw water passes through the filter bed 23 is provided. The differential pressure detection signal from the pressure sensor 33 is sent to the control device 34. The control device 34
An operation signal is output to a solenoid valve 29 that controls the supply of air,
Controls the stop and start of the transfer of the filter media by the air lift.

In the continuous filtration apparatus according to the embodiment shown in FIGS. 2 and 3, when the SS concentration of raw water such as sewage or river water or industrial water before treatment is high, If a flocculant or the like is added in advance before being supplied to the filtration devices 1 and 21 to agglomerate the turbidity into flocs to facilitate filtration, it is possible to obtain treated water of higher water quality. . The flocculant is not particularly limited, and for example, polyaluminum chloride (PAC), a sulfate band, or the like can be used.

In the continuous filtration apparatus according to each of the above embodiments, the transfer of the filter medium is intermittently stopped based on, for example, the pressure difference of the filter bed or a time set in advance by a timer, and the desired intermittent operation is performed. The transfer of the filter medium can be repeatedly stopped. By such intermittent transfer stop control of the filter medium, an appropriate cake layer is formed on the raw water inlet side of the filter bed during the stop of the transfer of the filter medium, and the accuracy of filtration is enhanced by the cake layer, and the quality of the treated water is improved. Is improved. By stopping the supply of the cleaning water even during the stoppage of the transfer, the amount of cleaning drainage is greatly reduced. The transfer and washing of the filter medium are performed intermittently based on the pressure difference of the filter bed and the time set by the timer so that the cake layer does not become too thick.

In addition to the above functions and effects, the following functions and effects can be obtained. That is, in general, in a continuous filtration device, in response to a change in the concentration of SS or the like of raw water,
The change in filter media washing and transfer speed (air lift)
Most preferred in terms of filtration performance. However, the control amount by the air lift can usually be changed only in the range of about 30 to 100%, and the fluctuation of the SS concentration of the raw water is usually much larger than that. Control is difficult. However, in the above-described embodiment, it is possible to substantially freely follow the variation ratio of the SS concentration of raw water simply by changing the operation rate (time interval) of intermittent transfer and cleaning (that is, a very large ratio). Therefore, it is possible to control the amount of the filter medium to be desirably washed and transferred in accordance with the state of the raw water described above.

Further, in the continuous filtration apparatus shown in FIGS. 2 and 3, in addition to the intermittent control of the transfer of the filter medium as described above, the transfer and the cleaning of the filter medium are continuously performed while the filter bed is continuously operated. So that the differential pressure is always controlled to the optimal differential pressure.
That is, it is also possible to adopt a method of controlling the pressure difference higher than the initial pressure difference so that the cake layer is always formed in the optimum layer.

That is, in the continuous filtration apparatus according to each embodiment as shown in FIGS. 2 and 3, when the raw water is continuously filtered, the pressure difference of the filter bed is substantially always higher than the initial pressure difference. The transfer amount of the filter medium is controlled so that the target value is also set to a high value. The transfer amount of the filter medium can be controlled by changing the supply air amount of the air lift pump. By setting the target value of the differential pressure to an appropriate value, an appropriate cake layer is always formed on the raw water inlet side of the filter bed, and the presence of the cake layer enables fine filtration at all times. Water quality is improved.

Since it is considered that the value of the pressure difference of the filter bed and the amount of the cake layer formed are substantially proportional to each other, by always controlling the differential pressure to an appropriate set target value, a desired cake layer can be automatically obtained. Will be formed. Therefore, the quality of the treated water is also stably maintained at a high level.
By such control, SDI (Silt D
efficiency Index: ASTM-D4189-9
2) are greatly reduced.

Referring again to FIG. 1, in the water treatment apparatus 100 according to the first embodiment of the present invention,
Raw water is supplied to a flow control valve 105 by a raw water supply pump 104.
While the flow rate is controlled, the continuous filtration device 101 (in FIG. 1, the configuration of the filtration device shown in FIG. 2 is employed in the improved continuous filtration device as shown in FIGS. 2 and 3). Shown) and filtered. The treated filtered water is stored in the filtered water receiving tank 103 via the overflow weir 106. From the filtered water receiving tank 103, the filtered water pump 1
07 to the film processing apparatus 102 at a desired flow rate,
The treated water treated by the membrane treatment device 102 is continuously obtained at a predetermined flow rate. In this embodiment, a part of the filtered water supplied by the filtered water pump 107 is sent to the washing device 8 of the filtering device 101 as washing water, and is discharged after washing.

The filtered water receiving tank 103 is provided with a water level detector 108 as a means for detecting the level of the stored filtered water. A signal of the water level detected by the water level detector 108 is sent to the control device 109. Can be The control device 109
Based on the detected water level, based on the detected water level, in order to always maintain the water storage amount (that is, the water level) of the filtered water receiving tank 103 so that a predetermined flow rate of the water to be treated is supplied to the membrane processing apparatus 102 by the filtered water pump 107. To control the supply amount. The supply amount of the raw water is determined based on a signal from the control device 109.
05 is controlled. Alternatively, the raw water supply pump 104 can be controlled by inverter control.

In the water treatment apparatus according to the first embodiment, since the continuous filtration apparatus 101 is used in the pretreatment of the membrane treatment apparatus 102, the filtration apparatus itself basically requires backwashing. As a result, there is no need to secure a sufficient amount of water for backwashing. Therefore, it is not necessary to install a large-capacity filtered water storage tank as in the conventional system. A small amount of filtered water is stored in the filtered water receiving tank 103, and a predetermined amount of filtered water is constantly supplied to the membrane processing device 102 therefrom.
The flow rate in the membrane processing apparatus 102 is controlled to be a desired constant flow rate, and the water level of the filtered water receiving tank 103 is controlled so that this flow rate can always be secured, so that the water level is always a predetermined value. Or within the prescribed range,
The flow rate control valve 105 controls the supply amount of raw water to the continuous filtration device 101. As a result, the filtered water receiving tank 103
Requires only a very small capacity, which is significantly smaller than conventional filtered water storage tanks. For example, what has conventionally required a retention capacity of about one hour is reduced to about one to five minutes. Therefore, the size of the entire system of the water treatment apparatus 100 is reduced, the installation space of the entire apparatus is reduced, and the cost is significantly reduced.

Further, as described above, by using an improved filtration device capable of obtaining higher-quality filtered water as the continuous filtration device 101, it is difficult to use it in place of the conventional fixed-bed filtration device. The existing continuous filtration device can be sufficiently practically used as a pretreatment device of the membrane treatment device. Therefore, in the present invention, in addition to the basic technical idea of controlling the supply amount of raw water to the continuous filtration device according to the flow rate of the membrane treatment device, by using the improved continuous filtration device as described above In addition, the size and cost of the water treatment system can be reduced more reliably.

FIG. 4 shows a water treatment apparatus 200 according to a second embodiment of the present invention. In the present embodiment, the continuous filtration device 101 itself is provided with a filtered water storage section 201, and a filtered water pump 107 is directly connected to a lower portion thereof.
The continuous filtration device 101 is provided with a water level detector 202 as means for detecting the water level of the treated water (filtrated water). Based on a signal of the water level detected by the water level detector 202, the control device 203 Thus, the supply amount of raw water to the continuous filtration device 101 via the flow control valve 105 is controlled. In such a configuration, substantially the same operation and effect as those of the first embodiment can be obtained.

FIG. 5 shows a water treatment apparatus 300 according to a third embodiment of the present invention. In this embodiment, as compared with the second embodiment, a water level detecting means is not provided, and a flow rate detecting detector 301 as a flow rate detecting means is provided in a flow path from the continuous filtration device 101 to the filtered water pump 107. Based on the flow rate detected by the detector 301, the control device 302 controls the supply amount of raw water to the continuous filtration device 101 via the flow control valve 105. In such a configuration, the discharge amount of filtered water from the continuous filtration device 101 is controlled such that the flow rate of the membrane processing device 102 is maintained at a desired constant flow rate. Therefore, substantially the same operation and effect can be obtained as when the water level of the continuous filtration device 101 is controlled to fall within a predetermined range.

[0047]

As described above, according to the water treatment apparatus of the present invention, a continuous filtration apparatus that does not require backwashing is used in the pre-treatment of the membrane treatment apparatus, and the flow rate is controlled according to the flow rate required for the membrane treatment apparatus. To control the supply of raw water to the continuous filtration device, eliminating the need for a large filtered water storage tank as in the past.
The size of the entire apparatus can be significantly reduced, and the cost can be reduced. In addition, since the raw water can be continuously filtered and then continuously subjected to membrane treatment, extremely efficient treatment can be performed. In addition, by improving the continuous filtration device to a configuration that is an improvement on the conventional device, it is possible to supply treated water with sufficiently high water quality to the membrane treatment device, and to secure the target performance of the entire water treatment system. can do.

[Brief description of the drawings]

FIG. 1 is an equipment system diagram of a water treatment apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing an example of a continuous filtration device suitable for use in the water treatment device of the present invention.

FIG. 3 is a schematic configuration diagram showing another example of a continuous filtration device suitable for use in the water treatment device of the present invention.

FIG. 4 is an equipment system diagram of a water treatment apparatus according to a second embodiment of the present invention.

FIG. 5 is an equipment system diagram of a water treatment apparatus according to a third embodiment of the present invention.

FIG. 6 is an equipment system diagram of a conventional water treatment apparatus.

[Explanation of symbols]

 1,21 Continuous filtration device 2,22 Tower 3,23 Filter bed 4,24 Raw water flow path 5 Supply pipe 6,25 Treated water outlet 7,26 Filter material transfer pipe 8,27 Washing device 9 Return path 10,28 Air supply Pipes 11, 16, 29 Solenoid valve or electromagnetic flow control valve 12 Screw 13 Wash water supply pipe 14 Nozzle 15 Drain pipe 17, 33 Pressure sensor 18, 34 Control device 30 Inner pipe 31 Outer pipe 32 Drain outlet 100, 200, 300 Water treatment device 101 Continuous filtration device 102 Membrane treatment device 103 Filtration water receiving tank as buffer tank 104 Raw water supply pump 105 Flow control valve 106 Overflow weir 107 Filtration water pump 108, 202 Water level detector 109, 203 as water level detection means , 302 Control device 201 Filtration water storage unit

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[Procedure amendment]

[Submission Date] December 13, 1999 (1999.12.
13)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 6

[Correction method] Change

[Correction contents]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C02F 1/44 B01D 29/08 520A 540A 29/38 580A

Claims (10)

[Claims] 1. A water system comprising a means for connecting a continuous filtration device upstream of a membrane treatment device and controlling a supply amount of raw water to the continuous filtration device according to a flow rate of the membrane treatment device. Processing equipment. 2. The water treatment apparatus according to claim 1, wherein said raw water supply amount control means has a buffer tank provided between a continuous filtration apparatus and a membrane treatment apparatus. 3. The water treatment apparatus according to claim 2, wherein a water level detection unit is provided in the buffer tank, and the raw water supply amount control unit controls the supply amount of the raw water based on the detected water level. . 4. The raw water supply amount control means has a treated water level detection means in a continuous filtration device, and controls the raw water supply amount based on the detected water level.
The water treatment device according to claim 1. 5. The raw water supply amount control means includes a flow rate detection means provided between the continuous filtration device and the membrane treatment device, and controls the raw water supply amount based on the detected flow rate. The water treatment apparatus according to claim 1, wherein 6. The water treatment apparatus according to claim 1, wherein the raw water supply amount means has a flow control valve in a raw water supply system to the continuous filtration device. 7. A continuous filtration device comprising: a filter bed of granular filter media;
Means for supplying raw water to the lower part of the filter bed, means for discharging treated water filtered by the filter bed from above the filter bed, means for extracting the filter medium at the lower part of the filter bed and transferring it to the surface of the filter bed, The water treatment apparatus according to any one of claims 1 to 6, further comprising: means for washing the filter; and control means for intermittently stopping the transfer of the filter medium. 8. A continuous filtration device comprising: a filter bed of granular filter media;
Means for supplying raw water to the lower part of the filter bed, means for discharging treated water filtered by the filter bed from above the filter bed, means for extracting the filter medium at the lower part of the filter bed and transferring it to the surface of the filter bed, Means for washing the filter, means for detecting the pressure difference of the filter bed,
The water according to any one of claims 1 to 6, further comprising means for controlling a transfer amount of the filter medium in the filter medium transferring means so that the detected differential pressure becomes a preset target value. Processing equipment. 9. The water treatment device according to claim 1, wherein said membrane treatment device comprises an ultrafiltration device. 10. The water treatment apparatus according to claim 1, wherein said membrane treatment device comprises a reverse osmosis membrane device.