JP2009154070A - Purified water recovering apparatus and method for recovering purified water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a purified water recovering apparatus which can relatively stably obtain purified water with high purity even in the case of waste water such as domestic waste water and industrial waste water. <P>SOLUTION: In the purified water recovering apparatus comprising a reverse osmosis membrane unit separating feed water into purified water as permeated water and concentrated water as non-permeated water by reverse osmosis membrane filtration, where waste water is fed as the feed water, and the purified water exhausted from the reverse osmosis membrane unit is recovered, the apparatus comprises: at least one selected from an impurity degree measuring device measuring the impurity degree of the feed water, the concentrated water or the purified water; and a valve mechanism including at least either a purified water valve regulating the flow rate of the purified water or a concentrated water valve regulating the flow rate of the concentrated water, and in the case the measured value measured by the impurity degree measuring device is not less than a standard value or exceeds the standard value, the permeability in the reverse osmosis membrane unit is limited by the valve mechanism. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a purified water recovery device including a reverse osmosis membrane unit and a purified water recovery method using the device.

Conventionally, this type of purified water recovery apparatus has been used in desalination of seawater, softening of brine, production of pure water for general use, and the like (for example, Patent Document 1).
And this kind of purified water collection | recovery apparatus has the advantage that relatively high purity purified water can be obtained.
JP 2005-279614 A

However, such a purified water recovery apparatus has a drawback that when the quality of the feed water (raw water) supplied to the reverse osmosis membrane unit to be filtered is deteriorated, the quality of the purified water obtained accordingly is also deteriorated. However, when domestic wastewater, factory wastewater, or the like is used as raw water, there is a problem that purified water with high purity cannot be obtained stably.
In other words, wastewater such as domestic wastewater and factory wastewater is so fluctuating that the inorganic salt concentration varies several times depending on the time zone even during one day, and the purity of purified water also fluctuates in proportion to it. It will be.

  In view of such problems, the present invention provides a purified water recovery apparatus and purified water that can obtain purified water with relatively high purity even in waste water such as domestic waste water, factory waste water, and waste leachate. It is an object to provide a recovery method.

In order to solve the above problems, the present invention includes a reverse osmosis membrane unit that separates supply water into purified water that is permeated water and concentrated water that is non-permeated water by reverse osmosis membrane filtration, and waste water is supplied as the supplied water. A purified water recovery device configured to recover purified water discharged from the reverse osmosis membrane unit,
At least one impurity measuring device for measuring the purity of the supply water, the concentrated water or the purified water, a purified water valve for adjusting the flow rate of the purified water, and a concentrated water valve for adjusting the flow rate of the concentrated water. And a valve mechanism including at least one of them, and the transmittance in the reverse osmosis membrane unit is controlled by the valve mechanism based on the measured value measured by the impurity measuring device. A water recovery device is provided.

The present invention further includes a reverse osmosis membrane unit that separates supply water into purified water that is permeated water and concentrated water that is non-permeated water by reverse osmosis membrane filtration in the flow direction, and a reverse osmosis membrane unit on the most upstream side. The waste water is supplied as the supply water, and the other reverse osmosis membrane units are arranged so that the concentrated water discharged from the preceding reverse osmosis membrane unit is supplied as the supply water, and the purification discharged from each reverse osmosis membrane unit. A purified water recovery device configured to recover water,
At least one of the purity measuring device for measuring the purity of the supplied water, the drained concentrated water, and the drained purified water supplied for at least one of the reverse osmosis membrane units, and the one reverse osmosis membrane unit A valve mechanism including at least one of a purified water valve for adjusting the flow rate of the purified water discharged and a concentrated water valve for adjusting the flow rate of the concentrated water discharged from the one reverse osmosis membrane unit, Provided is a purified water recovery apparatus characterized in that the permeability in the reverse osmosis membrane unit is controlled by the valve mechanism based on a measurement value measured by a purity measuring apparatus.

Further, the present invention includes a plurality of reverse osmosis membrane units in the flow direction for separating the feed water into permeated water and concentrated water that is non-permeated water by reverse osmosis membrane filtration. The other reverse osmosis membrane units are arranged so that the permeated water discharged from the previous reverse osmosis membrane unit is supplied as the feed water, and the permeated water from at least one of the reverse osmosis membrane units is supplied. A purified water recovery device configured to be recovered as purified water,
At least one of a purity measuring device for measuring the purity of supplied water, discharged concentrated water, discharged permeated water for at least one of the reverse osmosis membrane units, and from the one reverse osmosis membrane unit A valve mechanism including at least one of a permeate valve for adjusting the flow rate of discharged permeated water and a concentrated water valve for adjusting the flow rate of concentrated water discharged from the one reverse osmosis membrane unit. Provided is a purified water recovery apparatus characterized in that the transmittance of the one reverse osmosis membrane unit is controlled by the valve mechanism based on a measurement value measured by a purity measuring apparatus.

  Furthermore, the present invention provides a purified water recovery method characterized by purifying and recovering purified water from wastewater using such purified water recovery apparatus.

  In these purified water recovery devices and purified water recovery methods, if the purity of the wastewater is high, the status can be grasped by the impurity measuring device, and based on this, the permeation in the reverse osmosis membrane unit By controlling the rate, deterioration of the purified water obtained can be suppressed.

  As described above, according to the present invention, purified water having relatively high purity can be obtained even with wastewater such as domestic wastewater and factory wastewater.

  Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment First, a purified water recovery apparatus according to a first embodiment will be described.
FIG. 1 is a schematic view showing a purified water recovery apparatus according to the first embodiment.
As shown in FIG. 1, the purified water recovery apparatus of the first embodiment includes a reverse osmosis membrane unit 1 that separates supply water into purified water B that is permeated water and concentrated water C that is non-permeated water by reverse osmosis membrane filtration. One is provided.

  1 includes a reverse osmosis membrane unit 1 that supplies waste water A as supply water, separates the waste water A into purified water B and concentrated water, and discharges the purified water B and concentrates C. Is transferred to the outside of the system or to a concentrated water storage tank (not shown).

  In the purified water recovery apparatus of the first embodiment, a purified water transfer path 2 for transferring purified water B and a concentrated water transfer path 3 for transferring concentrated water C are formed.

Further, the purified water recovery apparatus of the first embodiment includes a valve mechanism including a purified water valve 11 for adjusting the flow rate of the purified water B and a concentrated water valve 12 for adjusting the flow rate of the concentrated water C. The flow rate is determined by the opening / closing operation.
The apparatus of FIG. 1 includes a valve mechanism including a purified water valve 11 and a concentrated water valve 12 interposed in the purified water transfer path 2 and the concentrated water transfer path 3, respectively. The flow rate is determined by opening and closing each valve.

Moreover, in 1st Embodiment, the feed water impurity measuring apparatus 20a1 which measures the purity of the feed water which is waste water, the feed water impurity measuring apparatus 20b1 which measures the purity of concentrated water, the purity of purified water The purity measuring apparatus 20 is provided with at least one of the supply water impurity measuring apparatus 20c1 for measuring the water content.
Furthermore, when the measured value measured by the impurity measuring device of the impurity measuring device 20 is equal to or greater than the reference value or exceeds the reference value, that is, the measured value measured by the feed water impurity measuring device 20a1 is When the reference value is equal to or higher than the reference value of the feed water, or when the measured value measured by the concentrated water impurity measuring device 20b1 is equal to or higher than the reference value of the concentrated water or exceeds the reference value, At least one of the purified water valve 11 and the concentrated water valve 12 when the measured value measured by the purity measuring device 20c1 is equal to or greater than the reference value of the purified water or exceeds the reference value. The permeability of the reverse osmosis membrane unit during normal operation (ie, less than the reference value or less than the reference value) by the valve mechanism that adjusts the flow rate by It is controlled to be lower than the time).

Examples of the impurity measuring apparatus 20 include an apparatus for measuring electrical conductivity, ion concentration, salt concentration, total soluble substance concentration (TDS), pH, or ORP.
Preferably, the electrical conductivity is generally used as a management index for the treatment performance of the reverse osmosis membrane, the electrical conductivity is measured from the viewpoint of the ease of maintenance and management of the measuring device, the ease of measurement, etc. A device can be mentioned.

A first boundary value indicating whether or not the transmittance in the reverse osmosis membrane unit should be lower than that during normal operation by a valve mechanism that adjusts the flow rate by at least one of the purified water valve 11 and the concentrated water valve 12. The reference value is determined from the viewpoint of obtaining purified water B having a predetermined purity or higher, or from the viewpoint of suppressing the scale attached to the reverse osmosis membrane.
For example, when electric conductivity is adopted as an impurity index, when 80% or more of the supplied water is recovered as purified water, the standard value of electric conductivity in the concentrated water is 5,000 μS / cm. It is preferably set in the following range, and the reference value of the electrical conductivity in the purified water is preferably set in a range of 1,000 μS / cm or less. For example, when obtaining purified water of tap water level, the reference value of the electrical conductivity in the purified water is preferably set in a range of 100 μS / cm or less.
Within such a range, purified water B with sufficiently high purity can be obtained, and the amount of scale attached to the reverse osmosis membrane is also reduced.

  The waste water A that can be used is not particularly limited, and examples thereof include steel, food, electric power, electronics, medicine, factory waste water such as automobiles, domestic waste water, and waste leachate.

  The purified water recovery apparatus of the first embodiment is configured as described above. Next, a method for recovering purified water B of the first embodiment using such a purified water recovery apparatus will be described.

  In the first embodiment, during normal operation, waste water A is supplied to the reverse osmosis membrane unit 1 as supply water, and the reverse osmosis membrane unit 1 separates purified water B into concentrated water C for purification. The water B is transferred to the purified water storage tank via the purified water transfer path 2, and the concentrated water C is transferred outside the system or to the concentrated water storage tank.

  In such a normal operation, the reverse osmosis membrane unit 1 is supplied by the purity of the feed water (waste water A) supplied to the reverse osmosis membrane unit 1 by the supply water impurity measurement device 20a1 and the concentrated water impurity measurement device 20b1. The purity of the concentrated water discharged from the water and the purity of the purified water discharged from the reverse osmosis membrane unit 1 by the purified water impurity measuring device 20c1 are measured periodically or continuously. Keep it.

  When the measured value is equal to or higher than the first reference value or exceeds the first reference value, a valve mechanism that adjusts the flow rate with at least one of the purified water valve 11 and the concentrated water valve 12, Control is performed so that the transmittance of the reverse osmosis membrane unit 1 is lower than that during normal operation.

Second Embodiment Next, a purified water recovery apparatus according to a second embodiment will be described.
In addition, the description which overlaps with 1st Embodiment is abbreviate | omitted, and the name and figure number of each part refer to the thing of 1st Embodiment suitably, and the thing which is not especially demonstrated in 2nd Embodiment is demonstrated in 1st Embodiment. The same content as
FIG. 2 is a schematic view showing a purified water recovery apparatus according to the second embodiment.
As shown in FIG. 2, the purified water recovery apparatus of the second embodiment includes a plurality of reverse osmosis membrane units 1 connected in tandem with respect to the direction of water flow, and the reverse osmosis membrane unit on the most upstream side. 1 is arranged so that waste water A is supplied as supply water, and the other reverse osmosis membrane units 1 are supplied with concentrated water C discharged from the preceding reverse osmosis membrane unit 1 as supply water. The purified water B discharged from the membrane unit 1 is configured to be collected.
In the apparatus of FIG. 2, the first reverse osmosis membrane unit 1a for supplying waste water A as supply water, separating the waste water A into purified water B and concentrated water C, and discharging the waste water A is provided. And a second reverse osmosis membrane unit 1b to which the concentrated water C discharged from the osmosis membrane unit 1a is supplied as supply water. Both the purified water B is recovered and the concentration discharged from the second reverse osmosis membrane unit 1b. The water C is transferred out of the system or to a concentrated water storage tank (not shown).

In the purified water recovery apparatus of the second embodiment, a plurality of paths 4, 5, 6, 7 for transferring purified water B or concentrated water C are formed.
The plurality of paths 4, 5, 6, and 7 include the purified water transfer paths 4 and 6 that transfer the purified water B discharged from each reverse osmosis membrane unit 1 and the concentrated water transfer paths that transfer the concentrated water C. 5 and 7 are provided.
Furthermore, the purified water recovery apparatus according to the second embodiment uses the purified water B or the supply water (usually the concentrated water C in the previous stage) supplied to any at least one reverse osmosis membrane unit 1 as necessary. Purified water transfer dilution path 8 for diluting with waste water A and concentrated water transfer path 7 for transferring concentrated water C discharged from reverse osmosis membrane unit 1 without supplying the supplied water to reverse osmosis membrane unit 1 And a detour route 9 for detouring.
For example, in the apparatus of FIG. 2, a first purified water transfer path 4 for sending purified water B from the first reverse osmosis membrane unit 1a to a purified water storage tank (not shown), and a first reverse osmosis membrane unit. 1st concentrated water transfer path 5 which sends concentrated water C from 1a to 2nd reverse osmosis membrane unit 1b, and 2nd purification which sends purified water B from 2nd reverse osmosis membrane unit 1b to a purified water storage tank (not shown) Discharge from the water transfer path 6, the second concentrated water transfer path 7 for sending the concentrated water C from the second reverse osmosis membrane unit 1b to the outside of the system or a concentrated water storage tank (not shown), and the first reverse osmosis membrane unit 1a. The purified water transfer dilution path 8 that connects the first purified water transfer path 4 and the first concentrated water transfer path 5 and the first reverse osmosis membrane unit 1a are discharged from the first reverse osmosis membrane unit 1a. The second concentrated water transfer path 7 without supplying the concentrated water C to the second reverse osmosis membrane unit 1b. And a bypass path 9 for communicating the first concentrated water transfer path 5 and the second concentrated water transfer path 7 in order to bypass.

Moreover, the purified water recovery apparatus of 2nd Embodiment is discharged | emitted from the purified water valve | bulb 11 which adjusts the flow volume of the purified water B discharged | emitted from at least any one reverse osmosis membrane unit 1, and this one reverse osmosis membrane unit 1. A valve mechanism including a concentrated water valve 12 for adjusting the flow rate of the concentrated water C is provided.
Specifically, a valve mechanism including a purified water valve 11 interposed in each of the purified water transfer path and the purified water transfer dilution path, and a concentrated water valve 12 interposed in each of the concentrated water transfer path and the detour path. The flow rate and flow path are determined by opening and closing each valve.
2 includes a first purified water transfer path 4, a second purified water transfer path 6, a first concentrated water transfer path 5, a second concentrated water transfer path 7, a purified water transfer dilution path 8, and a detour path. 9, a first purified water valve 11a, a second purified water valve 11b, a first concentrated water valve 12a, a second concentrated water valve 12b, and a third purified water valve 11c serving as a purified water transfer dilution path valve. In addition, a valve mechanism including a third concentrated water valve 12c serving as a bypass path valve is provided, and a flow path and a flow rate are determined by opening and closing operations of the respective opening and closing valves.

In the second embodiment, the feed water impurity measurement is performed to measure the purity of the supplied feed water (usually the concentrated water C in the previous stage) in any one of the reverse osmosis membrane units 1. The purity of at least one of the apparatus 20a2, the concentrated water impurity measuring apparatus 20b2 that measures the purity of the discharged concentrated water C, and the purified water impurity measuring apparatus 20c2 that measures the purity of the discharged purified water B A measuring device 20 is provided.
Furthermore, when the measured value measured by the impurity measuring device of the impurity measuring device 20 is greater than or equal to the reference value, that is, the measured value measured by the feed water impurity measuring device 20a2 is When it is greater than or equal to the reference value of the feed water, or when the measured value measured by the concentrated water impurity measuring device 20b2 is equal to or greater than the reference value of the concentrated water or exceeds the reference value, At least one of the purified water valve 11 and the concentrated water valve 12 when the measured value measured by the purity measuring device 20c2 is equal to or greater than the reference value of the purified water or exceeds the reference value. By the valve mechanism that adjusts the flow rate, the permeability in the reverse osmosis membrane unit 1 during normal operation (that is, less than the reference value or less than the reference value). It is controlled to be lower than when).
In FIG. 2, the feed water impurity measuring device 20a2 for measuring the purity of the feed water supplied to the second reverse osmosis membrane unit 1b and the concentrated water discharged from the second reverse osmosis membrane unit 1b. A configuration including a concentrated water impurity measuring device 20b2 for measuring the purity and a purified water impurity measuring device 20c2 for measuring the purity of the purified water discharged from the second reverse osmosis membrane unit 1b is illustrated.

  Further, in FIG. 2, the measurement value measured by the impurity measurement device of the impurity measurement device 20 is a second reference value that is separately determined (a reference value different from the reference value for controlling the valve mechanism). When it is the above or exceeds the second reference value, dilution by the purified water transfer dilution path 8 and bypass by the bypass path 9 are performed.

  The purified water recovery apparatus according to the second embodiment is configured as described above. Next, a method for recovering purified water B according to the second embodiment using the purified water recovery apparatus will be described.

In the second embodiment, during normal operation, wastewater A is supplied as supply water to the reverse osmosis membrane unit 1 on the most upstream side, and the purified water B is separated into concentrated water C by the reverse osmosis membrane unit 1. Then, the purified water B is transferred to the purified water storage tank through the purified water transfer path 4, and the concentrated water C is sequentially supplied to the reverse osmosis membrane unit 1 in the next stage as the supply water, and the downstream reverse osmosis membrane is sequentially supplied. The purified water B discharged from the unit 1 is transferred to the purified water storage tank via the purified water transfer path 6 and collected.
Then, the concentrated water C discharged from the reverse osmosis membrane unit 1 on the most downstream side is transferred to the outside of the system or the concentrated water storage tank.
In the case of using the apparatus of FIG. 2, the waste water A is supplied to the first reverse osmosis membrane unit 1a, and the purified water B discharged from the first reverse osmosis membrane unit 1a is transferred to the purified water storage tank. Then, the concentrated water C is supplied to the second reverse osmosis membrane unit 1b, the purified water B discharged from the second reverse osmosis membrane unit 1b is transferred to the purified water storage tank, and the concentrated water C is stored outside the system or concentrated water. Transfer to tank.

  During such normal operation, the supply water supplied to at least one of the reverse osmosis membrane units 1 by the supply water impurity measurement device 20a2 (the concentrated water discharged from the first reverse osmosis membrane unit 1a in FIG. 2). Concentrated water discharged from at least one of the reverse osmosis membrane units 1 by the device 20b2 for the purity of water C) and the concentrated water impurity (concentrated water C discharged from the second reverse osmosis membrane unit 1b in FIG. 2) Of purified water discharged from at least one of the reverse osmosis membrane units 1 (purified water B discharged from the second reverse osmosis membrane unit 1b in FIG. 2) by the purified water impurity measuring device 20c2. The purity of at least one of the purity is measured regularly or continuously.

When the measured value is equal to or higher than the first reference value or exceeds the first reference value, a valve mechanism that adjusts the flow rate with at least one of the purified water valve 11 and the concentrated water valve 12, Limit the permeability in the reverse osmosis membrane unit.
For example, when the apparatus shown in FIG. 2 is used, the first purified water valve 11a, the first concentrated water valve 12a, the second purified water valve 11b, the second concentrated water valve 12b, and the third purified water valve 11c. And the valve mechanism that adjusts the flow rate by at least one of the third concentrated water valves 12c, the permeability in the first reverse osmosis membrane unit 1a and the second reverse osmosis membrane unit 1b is lower than that in normal operation. To control.
Further, if the measured value is equal to or greater than the second reference value separately determined or exceeds the second reference value, if necessary, dilution by the purified water transfer dilution path 8 or bypass by the bypass path 9 is performed. To implement.
By performing such an operation, excessive concentration in the reverse osmosis membrane unit 1 can be suppressed, and scale adhesion to the membrane can also be suppressed.

Third Embodiment Next, a purified water recovery device and a method of recovering purified water B according to a third embodiment will be described.
In addition, the description which overlaps with 1st, 2nd embodiment is abbreviate | omitted, The name and figure number of each part refer to the thing of 1st, 2nd embodiment suitably, and what is not especially demonstrated in 3rd Embodiment, The contents are the same as those described in the first and second embodiments.
FIG. 3 is a schematic view showing the purified water recovery apparatus of the third embodiment.
As shown in FIG. 3, the purified water recovery apparatus according to the third embodiment includes a reverse osmosis membrane unit 1 that separates supplied water into permeated water and concentrated water C that is non-permeated water by reverse osmosis membrane filtration. ing.

More specifically, each has a plurality of reverse osmosis membrane units 1 connected in tandem with respect to the water flow direction. The reverse osmosis membrane unit 1 on the uppermost stream side is supplied with waste water A as the supply water, and the other reverse osmosis. The membrane unit 1 is arranged so that the permeated water discharged from the preceding reverse osmosis membrane unit 1 is supplied as supply water, and the permeated water discharged from at least one of the reverse osmosis membrane units 1 is recovered. It is comprised so that.
In the apparatus of FIG. 3, the first reverse osmosis membrane unit 1a for supplying waste water A as supply water, separating the waste water A into permeated water and concentrated water C, and discharging the waste water A, and the first reverse osmosis. A second reverse osmosis membrane unit 1b to which the permeated water discharged from the membrane unit 1a is supplied as supply water, and the purified water B as the permeated water discharged from the second reverse osmosis membrane unit 1b is recovered and the first The concentrated water C discharged from the reverse osmosis membrane unit 1a and the second reverse osmosis membrane unit 1b is transferred out of the system or to a concentrated water storage tank (not shown).

The purified water recovery apparatus of the third embodiment is provided with a plurality of pipes, and the permeated water discharged from each reverse osmosis membrane unit 1 is supplied to the reverse osmosis membrane unit 1 in the next stage or purified water as purified water. The storage tank is provided with a permeate transfer path 30 to be transferred.
Further, the purified water recovery apparatus of the third embodiment transfers the permeated water from at least any one of the reverse osmosis membrane units 1 to dilute the supply water upstream from the permeated water as necessary. A permeated water transfer dilution path 32 and a concentrated water transfer dilution path 34 for transferring the concentrated water C from any one of the reverse osmosis membrane units 1 and diluting the supply water upstream of the concentrated water C. I have.
For example, in the apparatus of FIG. 3, a first permeate transfer path 30a for transferring permeate discharged from the first reverse osmosis membrane unit 1a to the second reverse osmosis membrane unit 1b, and a first reverse osmosis membrane unit. The permeated water discharged from 1a is purified as purified water, and the second permeated water transfer path 30b is transferred to a purified water storage tank (not shown), and the permeated water discharged from the second reverse osmosis membrane unit 1b is purified as purified water. Permeated water for transferring the permeated water from the third reverse osmosis membrane unit 1b and diluting the water supplied to the first reverse osmosis membrane unit 1a by transferring the third permeated water transfer path 30c to the water storage tank (not shown). A transfer dilution path 32 and a concentrated water transfer dilution path 34 for transferring the concentrated water C from the second reverse osmosis membrane unit 1b to dilute the supply water of the first reverse osmosis membrane unit 1a are provided.

Moreover, the purified water collection | recovery apparatus of 3rd Embodiment is the concentrated water valve | bulb 12 interposed by the concentrated water transfer paths 5 and 7, and the concentrated water transfer dilution path 34, the permeated water transfer path 30, and the permeated water transfer dilution path, respectively. A valve mechanism including a permeate valve 31 interposed in each of the valves 32 is provided, and a flow path and a flow rate are determined by opening and closing each valve.
Specifically, the apparatus of FIG. 3 includes a first concentrated water transfer path 5, a second concentrated water transfer path 7, a first permeate transfer path 30a, a second permeate transfer path 30b, and a third permeate transfer path 30c. The first concentrated water valve 12d, the second concentrated water valve 12b, the first permeated water valve 31a, the second permeated water valve 31b, the second permeated water valve 31b, and the second permeated water valve 31b, respectively. A valve mechanism including a third permeate valve 31c, a fourth permeate valve 31d that is a permeate transfer dilution path valve, and a third concentrate water valve 12e that is a concentrate transfer dilute path valve. Is to be decided.

Further, in the third embodiment, a feed water impurity measuring apparatus that measures the purity of the feed water (usually the previous permeate) supplied in any at least one reverse osmosis membrane unit 1. 20a3, at least one impurity measuring device 20b3 for measuring the purity of the discharged concentrated water C, and 20p3 for measuring the purity of the discharged permeated water. 20 is provided.
Furthermore, when the measured value measured by the impurity measuring device of the impurity measuring device 20 is equal to or greater than the reference value or exceeds the reference value, that is, the measured value measured by the feed water impurity measuring device 20a3 is When the measured value measured by the concentrated water impurity measuring device 20b3 is equal to or larger than the reference value of the concentrated water or exceeds the reference value, and At least one of the permeated water valve 31 and the concentrated water valve 12 when the measured value measured by the purity measuring device 20c3 is equal to or more than the reference value of the permeated water or exceeds the reference value. Is controlled so that the permeability in the reverse osmosis membrane unit is lower than that in normal operation by a valve mechanism that adjusts the flow rate. .
In FIG. 3, the feed water impurity measuring device 20a3 for measuring the purity of the feed water supplied to the second reverse osmosis membrane unit 1b and the concentrated water discharged from the second reverse osmosis membrane unit 1b. The structure provided with the concentrated water impurity measuring apparatus 20b3 which measures an impurity, and the permeated water impurity measuring apparatus 20c3 which measures the impurity of the permeated water discharged | emitted from the 2nd reverse osmosis membrane unit 1b is shown in figure.

  Furthermore, in FIG. 3, when the measured value measured by the impurity measuring device of the impurity measuring device 20 is equal to or more than a second reference value determined separately or exceeds the second reference value, Dilution by the permeate transfer dilution path 32 and the concentrated water transfer dilution path 34 is performed.

  The first reference value, which is a boundary value as to whether or not to limit the transmittance in the reverse osmosis membrane unit by a valve mechanism that adjusts the flow rate by at least one of the permeate water valve 31 and the concentrated water valve 12, It is determined from the viewpoint of obtaining purified water B having a purity higher than a predetermined level, or from the viewpoint of suppressing scale adhering to the reverse osmosis membrane.

  The purified water recovery apparatus of the third embodiment is configured as described above. Next, a method of recovering purified water B of the third embodiment using such a purified water recovery apparatus will be described.

In the third embodiment, during normal operation, wastewater A is supplied as supply water to the reverse osmosis membrane unit 1 on the most upstream side, and the reverse osmosis membrane unit 1 separates the permeate into concentrated water C. Then, the concentrated water is transferred to the outside of the system or the concentrated water storage tank through the concentrated water transfer paths 5 and 7, and the permeated water is sequentially supplied to the reverse osmosis membrane unit 1 in the next stage via the permeated water transfer path 30. Then, the permeated water discharged from the reverse osmosis membrane unit 1 on the downstream side is sequentially transferred to the purified water storage tank through the permeated water transfer path 30 as the purified water B and collected.
In the case of using the apparatus of FIG. 3, waste water A is supplied to the first reverse osmosis membrane unit 1a, and the permeated water discharged from the first reverse osmosis membrane unit 1a is supplied to the second reverse osmosis membrane unit 1b. The permeated water discharged from the second reverse osmosis membrane unit 1b is transferred to the purified water storage tank as purified water B. Moreover, the concentrated water C discharged | emitted from this 1st reverse osmosis membrane unit 1a and the concentrated water C discharged | emitted from this 2nd reverse osmosis membrane unit 1b are transferred to a system outside or a concentrated water storage tank.

  During such normal operation, the feed water supplied to at least one reverse osmosis membrane unit 1 by the feed water impurity measuring device 20a3 (the permeate discharged from the first reverse osmosis membrane unit 1a in FIG. 3). Concentrated water discharged from at least one of the reverse osmosis membrane units 1 by the water purity / concentrated water impurity measuring device 20b3 (the concentrated water C discharged from the second reverse osmosis membrane unit 1b in FIG. 3) Impurity and impureness of the permeated water discharged from at least one reverse osmosis membrane unit 1 (permeated water discharged from the second reverse osmosis membrane unit 1b in FIG. 3) by at least one of the reverse osmosis membrane units 1 by the permeated water impurity measuring device 20c3. At least one impurity is measured regularly or continuously.

When the measured value is equal to or greater than the first reference value or exceeds the first reference value, a valve mechanism that adjusts the flow rate by at least one of the permeate valve 31 and the concentrated water valve 12, The transmittance in the reverse osmosis membrane unit is limited.
For example, when the apparatus shown in FIG. 3 is used, the first permeated water valve 31a, the first concentrated water valve 12d, the second permeated water valve 31b, the second concentrated water valve 12b, and the third permeated water valve 31c. The permeability in the first reverse osmosis membrane unit 1a and the second reverse osmosis membrane unit 1b is controlled by a valve mechanism that adjusts the flow rate by at least one of the third concentrated water valve 12e and the fourth permeated water valve 31d. To do.
Furthermore, if necessary, if the measured value is greater than or equal to the second reference value or exceeds the second reference value, for example when using the apparatus shown in FIG. Dilution is performed by at least one of the path 32 and the concentrated water transfer dilution path 34.

Other Embodiments The purified water recovery apparatus and the purified water B recovery method of the first, second, and third embodiments are as described above, but the present invention is limited to the first, second, and third embodiments. The design can be changed as appropriate.
For example, the purified water recovery apparatus of the first and second embodiments is configured to include both the purified water valve 11 and the concentrated water valve 12, and the purified water recovery apparatus of the third embodiment includes a permeated water valve 31 and In the present invention, either one of the concentrated water valve 12 and the concentrated water valve 12 may be provided.

Schematic which shows the purified water collection | recovery apparatus of one Embodiment, and the collection method of purified water. Schematic which shows the purified water collection | recovery apparatus of other embodiment and the collection method of purified water. Schematic which shows the purified water collection | recovery apparatus of other embodiment and the collection method of purified water.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reverse osmosis membrane unit, 11 ... Purified water valve, 12 ... Concentrated water valve, 20 ... Impurity measuring device, 31 ... Permeated water valve A ... Waste water, B ...・ Purified water, C ... Concentrated water

Claims (6)

A reverse osmosis membrane unit that separates supply water into purified water that is permeated water and concentrated water that is non-permeated water by reverse osmosis membrane filtration, and wastewater is supplied as the supplied water and purified from the reverse osmosis membrane unit A purified water recovery device configured to recover water,
At least one impurity measuring device for measuring the purity of the supply water, the concentrated water or the purified water, a purified water valve for adjusting the flow rate of the purified water, and a concentrated water valve for adjusting the flow rate of the concentrated water. And a valve mechanism including at least one of them, and the transmittance in the reverse osmosis membrane unit is controlled by the valve mechanism based on the measured value measured by the impurity measuring device. Water recovery device. A reverse osmosis membrane unit that separates the feed water into purified water that is permeated by reverse osmosis membrane filtration and concentrated water that is non-permeated water is provided in multiple stages in the flow direction. The other reverse osmosis membrane units are arranged so that the concentrated water discharged from the preceding reverse osmosis membrane unit is supplied as supply water, and the purified water discharged from each reverse osmosis membrane unit is recovered. A purified water recovery device configured as follows:
At least one of the purity measuring device for measuring the purity of the supplied water, the drained concentrated water, and the drained purified water supplied for at least one of the reverse osmosis membrane units, and the one reverse osmosis membrane unit A valve mechanism including at least one of a purified water valve for adjusting the flow rate of the purified water discharged and a concentrated water valve for adjusting the flow rate of the concentrated water discharged from the one reverse osmosis membrane unit, A purified water recovery apparatus, wherein a permeability of the reverse osmosis membrane unit is controlled by the valve mechanism based on a measured value measured by a purity measuring apparatus. A reverse osmosis membrane unit that separates feed water into permeate and non-permeate concentrated water by reverse osmosis membrane filtration has multiple stages in the flow direction, and the reverse osmosis membrane unit on the most upstream side is supplied with waste water as feed water, The other reverse osmosis membrane units are arranged so that the permeated water discharged from the preceding reverse osmosis membrane unit is supplied as supply water, and the permeated water from at least one of the reverse osmosis membrane units is recovered as purified water. A purified water recovery device configured as follows:
At least one of a purity measuring device for measuring the purity of supplied water, discharged concentrated water, discharged permeated water for at least one of the reverse osmosis membrane units, and from the one reverse osmosis membrane unit A valve mechanism including at least one of a permeate valve for adjusting the flow rate of discharged permeated water and a concentrated water valve for adjusting the flow rate of concentrated water discharged from the one reverse osmosis membrane unit. A purified water recovery apparatus, wherein a permeability of the one reverse osmosis membrane unit is controlled by the valve mechanism based on a measured value measured by a purity measuring apparatus.   When the measured value measured by the impurity measuring apparatus is greater than or equal to a reference value or exceeds the reference value, the valve mechanism controls the transmittance of the one reverse osmosis membrane unit to be lower than that during normal operation. The purified water recovery apparatus according to any one of claims 1 to 3.   The purified water recovery apparatus according to any one of claims 1 to 4, wherein the impurity measurement apparatus is an apparatus for measuring any one of electrical conductivity, ion concentration, salt concentration, total soluble substance concentration, pH, and ORP. .   6. A purified water recovery method comprising purifying purified water from waste water using the purified water recovery apparatus according to claim 1.

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