JP2009183920A - Liquid purifying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid purifying apparatus capable of reducing discharge amount of backwashing liquid flowing out during backwashing of a filter. <P>SOLUTION: The water purifying apparatus 10 is provided with a raw water tank 11 storing raw water supplied from a water supply source; a pump P1 feeding the raw water in the raw water tank 11 to a plurality of filters 12; a filtrate tank 15 storing filtrate purified by passing through the filters 12; a backwashing water tank 16 storing backwashing water; and a pump P2 feeding backwashing liquid in the backwashing water tank 16 to the filters 12. A three-way valve 22 serving as a flow path selector valve for switching flow-out direction of backwashing water based on the lapse of time after starting backwashing, and a control means 26 of the three-way valve 22, are provided as a mechanism for recovering backwashing water with a turbidity less than a given value from backwashing water flowing out of the filters 12 during backwashing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid purification apparatus that purifies water and other various liquids with a filter.

  In the apparatus for purifying water and other various liquids with a filter, various techniques have been proposed for backwashing the filter (see, for example, Patent Documents 1 to 3). In the backwashing method described in Patent Document 1, the backwashing conditions for the filtration membrane are set using the ratio of the organic suspended solids to the total amount of suspended solids contained in the raw water or the backwashed water as an index. The cleaning method for the pretreatment membrane described in Patent Document 2 is a configuration in which the pretreatment membrane is washed using salt-concentrated water fed from a reverse osmosis membrane device via a backwash line. In the backwashing method described in Patent Document 3, the iron powder concentration in the backwashing liquid discharged from the backwashing liquid tank is estimated with a turbidimeter, and when this iron powder concentration falls below a predetermined value, the backwashing liquid is used. The amount of backwash liquid discarded is reduced by stopping the discharge of water.

JP 2005-169238 A JP 2007-14902 A JP 2001-276514 A

  In the backwashing techniques described in Patent Documents 1 and 2, since the entire amount of backwashing liquid used for backwashing the filter is discharged to the outside, the backwashing liquid is wasted. In addition, much labor and materials are also spent on the wastewater treatment of the backwash liquid that flows out of the filter during backwashing.

  On the other hand, in the backwashing method described in Patent Document 3, it is determined whether to discard the backwashing liquid based on the iron powder concentration of the backwashing liquid estimated using a turbidimeter. The liquid recycling rate can be increased. However, since the backwashing liquid is once stored in a tank and allowed to stand for a predetermined time and then processed, it is extremely difficult to use the apparatus for purifying a large amount of liquid, such as a water supply facility.

  The problem to be solved by the present invention is to provide a liquid purification apparatus capable of reducing the amount of backwashing liquid that flows out during backwashing of a filter.

  As a result of repeatedly performing the reverse cleaning operation of the filter of the liquid purification apparatus, the present inventor has a constant turbidity of the reverse cleaning liquid flowing out from the filter during the reverse cleaning, from the start to the end of the reverse cleaning. The present invention was completed by discovering that it changes in the meantime and that the change pattern has regularity.

The liquid purification apparatus of the present invention includes a filter for purifying a stock solution supplied from a stock solution supply source, a back cleaning means for supplying back cleaning liquid to the filter, and a back cleaning liquid flowing out from the filter during back cleaning. And a discharge channel of
A recovery means is provided for recovering a portion of the backwash liquid that flows out to the discharge flow path during backwashing based on the elapsed time after the start of backwashing or the backwash liquid outflow amount. And

  After observing changes in the turbidity of the backwash liquid flowing out of the filter during backwashing in advance and understanding the time range or backwash liquid outflow range where the turbidity falls below the specified value, By collecting only the reverse cleaning liquid that flows out to the discharge path within the time range or the cleaning liquid outflow amount range, a portion having a turbidity of a predetermined value or less can be recovered. Accordingly, it is possible to reduce the amount of the backwash liquid that flows out during backwashing of the filter. The collected backwash liquid can be sent to the filter again to be purified, or reused for other purposes.

  Here, it is desirable to provide a flow path switching valve that switches the outflow destination of the discharge flow path based on the elapsed time after the start of reverse cleaning or the measured value of the outflow amount of the reverse cleaning liquid as the recovery means. With such a configuration, it is possible to select the collection and disposal of the backwash liquid with a simple mechanism that operates the flow path switching valve according to the elapsed time after the start of backwashing or the measured value of the backwash liquid outflow amount. it can.

  In this case, it is desirable to arrange the flow path switching valve in the discharge flow path nearest to the filter. In such a configuration, since the spillover destination is switched at the part where the turbidity change of the backwash liquid flowing out from the filter first appears during backwashing, the correct selection of recovery and disposal of the backwash liquid is performed. It can be carried out.

  On the other hand, a turbidity meter for detecting the turbidity of the backwash liquid flowing out from the filter during backwashing may be provided. With such a configuration, it is possible to measure in advance using a turbidimeter when observing changes in turbidity of the backwash liquid flowing out from the filter during backwashing, so the turbidity is below a predetermined value. It is possible to accurately set the time range or the backwash liquid outflow range. Further, since the actual turbidity of the backwash liquid flowing out from the filter can be detected, it is possible to accurately cope with unexpected turbidity changes.

  According to the present invention, it is possible to provide a liquid purification apparatus capable of reducing the amount of backwashing liquid that flows out during backwashing of a filter.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a water purification apparatus according to the first embodiment of the present invention.

  A water purification device 10 shown in FIG. 1 is an example of a liquid purification device according to the present invention, and is a water purifying device of a total amount filtration method. The raw water tank 11 for storing raw water supplied from a water supply source (not shown), the pump P1 for sending the raw water in the raw water tank 11 to the plurality of filters 12, and the filter 12 are purified. A permeated water tank 15 for storing the permeated water. Moreover, the reverse washing water tank 16 which stores reverse washing water, and the pump P2 for feeding the reverse washing liquid in the reverse washing water tank 16 to the filter 12 are provided. The plurality of filters 12 are all of the internal pressure type hollow fiber type, but are not limited thereto.

  In each flow path 32 communicating with each filter 12, a three-way valve 22 that is a flow path switching valve is disposed, and a turbidimeter 27 is disposed between the three-way valve 22 and the filter 12. A flow path 35 for discharging the backwash water is connected to the three-way valve 22, and control means 26 for switching the three-way valve 22 is provided. Further, on-off valves 13, 17 and a pressure gauge 42 are disposed in the flow path 33 extending from the raw water tank 11, and on-off valves 18, 28, and the pressure gauge 42 are disposed in the flow path 38 extending from the backwash water tank 16. A pressure gauge 43 is arranged.

  When the raw water purification operation is performed in the water purification device 10, the on-off valves 21 and 28 are closed, the pump P2 is stopped, the on-off valves 13, 17, 29, and 19 are opened, and the three-way valve 22 is filtered through the flow path 32. After setting the device 12 to communicate with the pump 12, the pump P1 is operated. As a result, the raw water in the raw water tank 11 is sent to the filter 12 via the flow paths 30, 31, 32 and the three-way valve 22. The permeated water that has been purified by passing through the filter 12 passes through the flow path 36, the on-off valve 29, the flow path 37, and the on-off valve 19 and is stored in the permeated water tank 15. The permeated water in the permeated water tank 15 is supplied to a predetermined location by opening the on-off valve 20, but can also be supplied directly from the on-off valve 19 to the destination location.

  If the purification operation is continued, suspended substances in the raw water accumulate in the filter 12 and the filtration function deteriorates. However, the indicated value of the pressure gauge 42 increases accordingly, and the indicated value exceeds the predetermined value. At this point, the filter 12 is back-washed. In this case, the cleaning operation is temporarily stopped by reversely feeding the backwashing water in the backwashing water tank 16 back to the filter 12. The water purification apparatus 10 of the present embodiment is provided with a mechanism that collects a portion of the backwash water that flows out from the filter 12 during backwashing that has a turbidity of a predetermined value or less.

  Hereinafter, the backwash water recovery mechanism in the water purification apparatus 10 will be described. First, in order to recover a portion of the backwash water that flows out from the filter 12 during backwashing that has a turbidity of a predetermined value or less (that is, a portion having a high cleanliness), the predetermined value that serves as a selection criterion thereof is used. Need to be set. Therefore, after the filtration function of the filter 12 is lowered, the pump P1 is stopped, the on-off valves 17, 21, 29 are closed, and the three-way valve 22 is switched to a state in which each filter 12 and the flow path 35 are communicated. Then, the on-off valves 18 and 28 are opened, and the pump P2 is operated. As a result, the backwash water in the backwash water tank 16 is sent back to the respective filters 12 via the flow paths 38 and 36 and flows back through the respective filters 12 and then passes through the three-way valve 22. It is discharged from the flow path 35.

  Here, when the turbidity of the backwash water flowing out from each filter 12 is measured by the turbidimeter 27 and the correlation between the elapsed time after the start of backwashing and the change in turbidity is obtained, for example, immediately after the start of backwashing Although the turbidity of the backwash water flowing out into the water is low, the turbidity increases with the passage of time, and after showing a peak value, regularity is found such that the turbidity decreases again. Therefore, only the high turbidity reverse wash water flowing out within the predetermined time Y range after the start of reverse cleaning is discarded, and the low turbidity flowing out within the predetermined time X range before and within the predetermined time Z range thereafter. Set to collect backwash water.

  Specifically, based on the regularity, if the switching time (predetermined times X, Y, Z) of the three-way valve 22 is input to the control means 26 in advance, the predetermined times X, Y, Each time Z elapses, the three-way valve 22 is switched by a signal from the control means 26. In this embodiment, the turbidity of the backwash water flowing out from the filter 12 is measured by the turbidimeter 27. However, the turbidity meter 27 is not limited to this, so the backwash water is visually observed or other means. It is also possible to set the switching timing (predetermined times X, Y, Z) of the three-way valve 22 based on the measured turbidity.

  The three-way valve 22 is set to a recovery mode in which the filter 12 communicates with the flow path 32 until the predetermined time X elapses after the start of the reverse cleaning, the on-off valve 21 is opened, and the three-way valve 25 is connected to the flow paths 39, 40 is communicated. Therefore, the low turbidity backwash water flowing out from the filter 12 until the predetermined time X passes through the three-way valve 22 through the flow paths 32 and 31, and the on-off valve 21, the flow path 39, the three-way valve 25, and the like. It flows into the raw water tank 11 via the flow path 40.

  When the predetermined time X has elapsed, the signal from the control means 26 switches the three-way valve 22 to a discard mode that communicates from the filter 12 to the flow path 35, and the on-off valve 21 is closed. Until the time elapses, the highly turbid backwash water flowing out from the filter 12 passes through the flow path 35 from the three-way valve 22 and is discharged to a predetermined drainage facility (not shown).

  When the predetermined time Y elapses, the signal from the control means 26 sets the three-way valve 22 again in the recovery mode in which the filter 12 communicates with the flow path 32, the on-off valve 21 is opened, and the three-way valve 25 is set in the flow path 39. , 40 are communicated. Therefore, the low turbidity backwash water flowing out from the filter 12 until the predetermined time Z passes thereafter passes from the three-way valve 22 through the flow paths 32 and 31 to the on-off valve 21, the flow path 39, and the three-way. It flows into the raw water tank 11 via the valve 25 and the flow path 40.

  When the predetermined time Z has elapsed, the pump P2 is stopped, the on-off valves 21 and 28 are closed, the on-off valves 17 and 29 are opened, and the three-way valve 22 is set in a state where the flow path 32 and the filter 12 are communicated. Therefore, after that, if the pump P1 is operated, the raw water feed from the raw water tank 11 to the filter 12 starts, and the purification operation of the raw water is resumed. The backwash water remaining in the flow paths 39 and 40 can be discharged from the flow path 41 by switching the three-way valve 25.

  In this way, if the turbidity change of the backwash water flowing out from the filter 12 during backwashing is observed in advance, the time range (predetermined time X, Z) in which the turbidity falls below a predetermined value should be grasped. By collecting only the backwashing water flowing out from the filter 12 within the time range (predetermined time X, Z) after the start of backwashing, a portion having a turbidity of a predetermined value or less can be collected. Therefore, the amount of backwashing water that flows out during backwashing of the filter 12 can be reduced. In the present embodiment, after the backwash water is collected in the raw water tank 11, it is again sent to the filter 12 for purification, but is not limited to this, and may be reused for other purposes. it can.

  In the water purification apparatus 10, as a means for collecting the backwash water, a flow path switching valve that switches the outflow destination of the backwash water based on the measured value of the elapsed time (predetermined time X, Y, Z) after the start of backwashing. A certain three-way valve 22 is provided. Therefore, it is possible to accurately select the collection and disposal of the backwashing liquid, although it is a simple mechanism in which the control means 26 operates the three-way valve 22 according to the elapsed time after the start of backwashing. It is also possible to adopt a method of switching the backflow destination of the backwashing liquid based on the measured value of the backwashing liquid outflow amount from the filter 12 after the start of backwashing.

  Further, by arranging the three-way valve 22 in the flow path 32 closest to the filter 12, the flow destination is switched at the portion where the turbidity change of the reverse cleaning liquid flowing out from the filter 12 first appears during the reverse cleaning. Therefore, it is possible to accurately select whether or not to collect the backwash water.

  Further, since a turbidimeter 27 for detecting the turbidity of the backwash liquid flowing out from the filter 12 during backwashing is disposed between the filter 12 and the three-way valve 22, a predetermined time X, Y, Z is set in advance. The turbidity meter 27 can be used when measuring the turbidity for setting. For this reason, the time range (or backwashing liquid outflow amount range) in which the turbidity is not more than a predetermined value can be accurately set. Further, since the actual turbidity of the backwash liquid flowing out from the filter 12 can be detected, it is possible to accurately cope with unexpected turbidity changes. The water purification apparatus 10 includes three filters 12. However, the number, size, type, and the like of the filter 12 are not limited. It can be arbitrarily set according to.

  Next, a second embodiment of the present invention will be described based on FIG. FIG. 2 is a diagram showing a schematic configuration of a water purification apparatus according to the second embodiment of the present invention. 2 that have the same reference numerals as those in FIG. 1 are parts having the same structure and function as the constituent parts of the water purification apparatus 10, and the description thereof is omitted.

  The water purification apparatus 50 shown in FIG. 2 is an example of the liquid purification apparatus according to the present invention, and is a cross-flow type water purification apparatus. The three filters 52 are all of the internal pressure type hollow fiber type, but the type, size, number and the like of the filters are not limited to these, and can be arbitrarily set according to the use conditions.

  When the raw water purification operation is performed in the water purification device 50, the on-off valves 21 and 28 are closed, the pump P2 is stopped, the on-off valves 13, 17, 29, and 19 are opened, and the three-way valve 22a is filtered with the flow path 32. The three-way valve 22b is set in a state in which the filter 52 and the flow path 31b are in communication with each other, and the pump P1 is operated. Thereby, the raw water in the raw water tank 11 is sent to the filter 52 through the flow paths 30, 31a, 32 and the three-way valve 22a. The permeated water purified by passing through the filter 52 passes through the flow path 36, the on-off valve 29, the flow path 37, and the on-off valve 19 and is stored in the permeated water tank 15. The permeated water in the permeated water tank 15 can be supplied to a predetermined location by opening the on-off valve 20 or can be directly supplied from the on-off valve 19 to a destination location.

  On the other hand, the concentrated water that has passed through the filter 52 is sent to the raw water tank 11 through the three-way valve 22b, the flow paths 31b and 39, the three-way valve 25, and the flow path 40, and again through the flow path 30 and the like described above. It is sent to the filter 52 and purified.

  Next, the reverse washing water recovery mechanism in the water purification apparatus 50 will be described. As in the case of the water purifier 10, the backwash water flowing out from the filter 52 during backwashing is selected to recover a portion with a turbidity of a predetermined value or less (ie, a portion with a high cleanliness). The predetermined value serving as a reference is set. After the filtration function of the filter 52 is lowered, the pump P1 is stopped, the on-off valves 17, 21, 29 are closed, and the three-way valves 22a, 22b are switched to a state in which each filter 52 and the flow path 35 are communicated. Then, the on-off valves 18 and 28 are opened, and the pump P2 is operated. As a result, the backwash water in the backwash water tank 16 is sent back to the filters 52 via the flow paths 38 and 36, passes through the filter 12, and then passes through the three-way valves 22a and 22b. It is discharged from the flow path 35.

  Here, the turbidity of the backwash water flowing out from each filter 52 is measured by the turbidimeter 27, the correlation between the elapsed time after the start of backwashing and the change in turbidity is obtained, and the regularity found there. Based on the above, the predetermined times X, Y, and Z are determined as in the case of the water purifier 10. Then, only the high turbidity reverse wash water flowing out within the predetermined time Y range after the start of reverse cleaning is discarded, and the low turbidity flowing out during the predetermined time X before and after the predetermined time Z. Set to collect backwash water.

  Specifically, based on the regularity, the switching timing (predetermined times X, Y, Z) of the three-way valves 22a, 22b, which are flow path switching valves, is input in advance to the control means 26, and after the start of back washing, Whenever the time X, Y, Z elapses, the three-way valves 22a, 22b are switched by a signal from the control means 26.

  The three-way valve 22a communicates with the filter 52 and the flow path 32 and the three-way valve 22b communicates with the filter 52 and the flow path 31b until the predetermined time X elapses after the start of reverse cleaning. The on-off valve 21 is set, and the three-way valve 25 communicates the flow paths 39 and 40. Accordingly, the low turbidity backwash water that has passed through the filter 52 until the predetermined time X has passed flows out of the three-way valves 22a and 22b. The backwash water flowing out from the three-way valve 22a flows into the raw water tank 11 via the flow paths 32, 31a, 39, the open / close valve 25 and the flow path 40, and the reverse wash water flowing out from the three-way valve 22b is passed through the flow paths 31b, 39, flows into the raw water tank 11 through the on-off valve 25 and the flow path 40.

  When the predetermined time X elapses, the three-way valves 22a and 22b are switched to a discard mode in which the filter 52 and the flow path 35 are communicated by a signal from the control means 26, and the on-off valve 21 is closed. Until the time Y elapses, the highly turbid backwash water flowing out from the filter 52 passes through the flow path 35 from the three-way valves 22a and 22b and is discharged to a predetermined drainage facility (not shown). .

  When the predetermined time Y elapses, the signal from the control means 26 sets the three-way valves 22a and 22b again in the recovery mode for communicating the filter 52 and the flow paths 32 and 31b, opens the on-off valve 21 and opens the three-way valve. 25 becomes the state which connects the flow paths 39 and 40. FIG. Accordingly, the low turbidity backwash water flowing out of the filter 52 before the predetermined time Z passes through the flow paths 32 and 31a or the flow paths 31b and 39, the three-way valve 25 and the flow path 40 thereafter. And flows into the raw water tank 11.

  When the predetermined time Z elapses, the pump P2 is stopped, the on-off valves 21 and 28 are closed, the on-off valves 17 and 29 are opened, the three-way valve 22a communicates the flow path 32 and the filter 52, and the three-way valve 22b The filter 52 and the flow path 31b are set to communicate with each other. Therefore, if the pump P1 is operated thereafter, the raw water supply from the raw water tank 11 to the filter 52 starts, and the purification operation of the raw water is resumed. The backwash water remaining in the flow paths 39 and 40 can be discharged from the flow path 41 by switching the three-way valve 25.

  As described above, if the turbidity change of the backwash water flowing out from the filter 52 during backwashing is observed in advance, the time range (predetermined time X, Z) in which the turbidity is less than or equal to the predetermined value should be grasped. By collecting only the backwashing water flowing out from the filter 52 within the time range (predetermined time X, Z) after the start of backwashing, a portion having a turbidity of a predetermined value or less can be collected. Accordingly, it is possible to reduce the amount of backwashing water that flows out during backwashing of the filter 52. In the present embodiment, after the backwash water is collected in the raw water tank 11, it is sent again to the filter 52 for purification, but is not limited to this, and may be reused for other purposes. it can. Other structures and functions are the same as those of the water purification device 10 described above.

  The filtration device of the present invention can be widely used as water purification means or other liquid purification means.

It is a figure which shows schematic structure of the water purification apparatus which is 1st Embodiment of this invention. It is a figure which shows schematic structure of the water purification apparatus which is 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,50 Water purification apparatus 11 Raw water tank 12,52 Filter 13,17,18,19,20,21,28,29 On-off valve 15 Permeate water tank 16 Backwash water tank 22,22a, 22b, 25 Three-way valve 27 Turbidimeter 30, 31, 31a, 31b, 32, 33, 35, 36, 37, 38, 39, 40, 41 Flow path 42, 43 Pressure gauge P1, P2 Pump X, Y, Z Predetermined time

Claims (4)

A filter for purifying the stock solution supplied from the stock solution supply source, backwashing means for feeding backwashing liquid to the filter, and a discharge channel for backwashing liquid flowing out from the filter during backwashing. ,
A recovery means is provided for recovering a portion of the backwash liquid flowing out of the filter during backwashing with a turbidity of a predetermined value or less based on the elapsed time after the start of backwashing or the backwash liquid outflow amount. Liquid purification device.   2. The flow path switching valve that switches the outflow destination of the discharge flow path based on the elapsed time after the start of reverse cleaning or the measured value of the outflow amount of the reverse cleaning liquid is provided as the recovery means. Liquid purification equipment.   The liquid purification apparatus according to claim 1, wherein the flow path switching valve is disposed in the discharge flow path closest to the filter.   The liquid purification apparatus in any one of Claims 1-3 which provided the turbidity meter which detects the turbidity of the said backwashing liquid which flows out out of the said filter during backwashing.

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