JPH11192482A - Polyvalent metal containing water purifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain purified water having few residual oxidizers by oxidizing a part of polyvalent metal ions contained in raw water in an oxidizing tank, filtering the oxidized raw water containing polyvalent metal ions by a reverse osmosis membrane to separate it permeated water and concentrated water and also returning the concentrated water to the oxidizing tank. SOLUTION: When purifying raw water such as polyvalent metal ion containing underground water, a part of polyvalent metal ions are oxidized in an oxidizing tank 2, and oxide of polyvalent metals are made into the solid content, and this solid content and the polyvalent metal containing raw water is sent to a solid content removing device 3. In the solid content removing device 3, the oxides of polyvalent metals and the other solid content present in the oxidized raw water are removed to discharge primary purified water. The primary purified water is sent to a reverse osmosis filter 4 to remove the polyvalent metal ions in the primary purified water there. Concentrated water separated by the reverse osmosis filter 4 is returned to the oxidizing tank 2 to oxidize the polyvalent metal containing water by an oxidizer in this concentrated water together with an oxidizer newly added thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyvalent metal-containing water purification apparatus, and more particularly, to obtain purified water obtained by removing polyvalent metal ions to a reference value or less, and to discard concentrated water. Efficient use of polyvalent metal-containing water purification equipment that can be effectively used without purification, and purified water obtained by removing polyvalent metal ions to below a reference value can be obtained, and the concentrated water can be effectively used without being discarded The present invention relates to a long-life and efficient polyvalent metal-containing water purification device.

[0002]

2. Description of the Related Art Well water,
In addition, groundwater and the like contain a polyvalent metal having a valence of two or more in the form of ions. Water containing divalent or higher polyvalent metal ions is referred to as polyvalent metal-containing water. In order to provide polyvalent metal-containing water for drinking, it is necessary to remove polyvalent metal ions from the polyvalent metal-containing water.

[0003] As a method for removing iron ions, one of the polyvalent metal ions, for example, an air oxidation method has been conventionally known. This air oxidation method generates iron oxide by blowing air into iron ion-containing water to oxidize iron ions,
In this method, the generated iron oxide is precipitated as a solid content, and then the solid content is removed.

However, this air oxidation method requires, for example, a sedimentation basin and the like, and the entire apparatus for removing iron ions becomes extremely large. In this air oxidation method, there is a problem that coagulation of iron oxides becomes difficult when silica coexists in water containing iron ions, or when humic substances, sulfides, and ammonia coexist in water containing iron ions. There is also a problem that the ion oxidation reaction does not proceed smoothly.

As a method for removing iron ions, there are a method using chlorine oxidation and a method using ozone oxidation. Also in the removal of iron ions by the chlorine oxidation method and the ozone oxidation method, similarly to the air oxidation method, there is a problem that the entire apparatus becomes large.

As a method different from the iron removal method by oxidation, there is a method using a reverse osmosis membrane. In the iron elimination method using the reverse osmosis membrane, 50 to 50%
70% is discharged as retentate. In other words, this method can purify only about 30 to 50% of the raw water, and is a method with low purification efficiency.

As a method for removing manganese ions which are one of the polyvalent metal ions, there is a manganese removal method by direct filtration, but this method has a problem that the whole apparatus becomes very large. As another method for removing manganese ions, there is a method for removing manganese by oxidation with ozone. However, as in the case of removing iron ions, there is a problem that the entire apparatus becomes large. As a method of removing manganese ions,
Although there is a method using a reverse osmosis membrane, the purification efficiency is low similarly to the iron removal method.

On the other hand, when a public purification facility or the like becomes inoperable due to a disaster or the like, or in a place where a large purification facility cannot be provided such as a mountainous area, it is necessary to efficiently remove polyvalent metals. There is a need for a small-sized purification device that can be used.

The present invention has been completed based on the above circumstances.

[0010] That is, an object of the present invention is to provide a small polyvalent metal-containing water purification device capable of efficiently removing polyvalent metals from polyvalent metal-containing water.

Another object of the present invention is to provide a small-sized metal ion capable of efficiently removing polyvalent metal ions, particularly iron ions and manganese ions, in polyvalent metal-containing water and maintaining its removal ability for a long period of time. An object of the present invention is to provide a polyvalent metal-containing water removing device.

Another object of the present invention is to remove polyvalent metal ions in polyvalent metal-containing water by reusing a small-sized polyhydric oxidant contained in a concentrated solution generated during the removing operation. An object of the present invention is to provide a valent metal-containing water purification device.

[0013] In addition, an object of the present invention is to obtain purified water having a low content of polyvalent metal ions and to reduce damage to the apparatus due to residual oxidant remaining in the liquid discharged from the oxidation tank. Another object of the present invention is to provide a small polyvalent metal-containing water purification device.

It is a further object of the present invention to provide a small polyvalent metal-containing water purifying apparatus capable of obtaining purified water having a low polyvalent metal ion content and a low residual oxidizing agent content. It is in.

Still another object of the present invention is preferably used when a public purification facility becomes inoperable due to a disaster or the like, and in a mountainous place or a narrow place where a large purification facility cannot be installed. An object of the present invention is to provide a small polyvalent metal-containing water purification device.

[0016]

According to an aspect of the present invention for solving the above-mentioned problems, (1) an oxidation tank for oxidizing a part of polyvalent metal ions contained in raw water; A reverse osmosis filtration device that oxidizes the raw water that has been oxidized in the oxidation tank and contains polyvalent metal ions through a reverse osmosis membrane and separates it into permeated water and concentrated water, and (3) condensing with the reverse osmosis filtration device And a water feed line for returning the concentrated water returned to the oxidation tank.
An oxidation tank for oxidizing a portion of the polyvalent metal ions contained in the raw water; and (2) a solid content that is oxidized in the oxidation tank and removes solids in the oxidized raw water containing the polyvalent metal ions. (3) a reverse osmosis filtration device for filtering the primary purified water from which solids have been removed by the solids removal device with a reverse osmosis membrane to separate the purified water into permeated water and concentrated water; A polyvalent metal-containing water purification device, comprising: a water supply line that returns concentrated water concentrated by an osmosis filtration device to the oxidation tank; (1) polyvalent metal ions contained in raw water An oxidation tank for oxidizing a part of the oxidized water; (2) a solids removal device for removing solids in the oxidized raw water which is oxidized in the oxidation tank and contains residual polyvalent metal ions; and Treatment of primary purified water from which solids have been removed by a solids remover to remove oxidant remaining in the primary purified water An oxidizing agent removing device, (4) a reverse osmosis filtering device for filtering the treatment liquid discharged from the oxidizing agent removing device through a reverse osmosis membrane and separating the permeated water and the concentrated water, and (5) the reverse osmosis. A polyvalent metal-containing water purifier characterized by comprising a water supply line for returning the concentrated water concentrated by the filtration device to the oxidation tank, and in one aspect of these polyvalent metal-containing water purifiers, The solid content removing device comprises a drain drainage channel for discharging a part of the solid content-containing concentrated liquid generated by the solid content removal, and in one aspect of these polyvalent metal-containing water purification devices, The oxidizing agent removing device is a reduction tank that neutralizes the residual oxidizing agent contained in the primary purified water, or a filtration filter that adsorbs and filters the residual oxidizing agent contained in the primary purified water, and contains these polyvalent metals. In one embodiment of the water purification device , The filtration device and / or the reverse osmosis filtration device includes one or both of a backwashing device and a flushing device.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a polyvalent metal-containing water purification device (hereinafter sometimes referred to as a "water purification device" or "purification device") 1 which is an example of the present invention is oxidized. A tank 2, a solid content removing device 3, a reverse osmosis filtration device 4,
And a water supply line 5.

The oxidizing tank 2 mixes polyvalent metal-containing water containing polyvalent metal ions, for example, well water, concentrated water supplied by a water supply line 5 and an oxidizing agent to be newly added, and This is a device that oxidizes some of the polyvalent metal ions. One of the important points in the present invention is that the oxidation tank 2 does not oxidize all the polyvalent metal ions in the polyvalent metal-containing water but oxidizes a part of the polyvalent metal ions, for example, It is to change to a valent metal oxide.

The oxidation is generally carried out at normal temperature and pressure.
Perform for 0-120 minutes. In the present specification, oxidizing at "normal temperature" means oxidizing without performing forced heating or forced cooling. In other words, particularly heating and cooling the inside of the oxidation tank 2 are not performed. Without oxidizing. Also, oxidizing under “normal pressure” means that oxidizing is performed without performing a forced pressurizing operation or a forced depressurizing operation. In other words, the inside of the oxidation tank 2 is particularly pressurized and depressurized. It means not to perform oxidation.

"Partially oxidize polyvalent metal ions"
Means that a part of the polyvalent metal ions in the well water or the like is oxidized and converted into a solid content such as a metal oxide as described above. Therefore, the liquid discharged from the oxidation tank 2, that is, the raw water for oxidation treatment contains polyvalent metal ions and
Solids such as metal oxides generated by oxidation of the polyvalent metal ions are mixed. In some cases, the untreated oxidizing agent, that is, a residual oxidizing agent, is contained in the oxidized raw water.

In the oxidation tank 2, the ratio of "partially oxidizing polyvalent metal ions" in raw water such as well water, that is, the ratio of the polyvalent metal ions contained in the raw water which is oxidized and removed is as follows. , Water quality such as FI (dirt coefficient) and polyvalent metal ion concentration in the oxidized raw water,
Reverse osmosis membrane device 14 included in reverse osmosis membrane filtration device 4 described later
Can be determined so as to satisfy the water quality standard of the supply water in.

Here, the FI is an FI described below.
It can be determined as follows using a measuring device.

As the FI measuring device, for example, a sample water tank for storing the sample water, a pressurizing device for pressurizing the inside of the sample water tank, a membrane filter for filtering off a pollutant component, that is, a solid content in the sample water, An apparatus including a sample water pipe connecting the sample water tank and the membrane filter section and a cylinder for collecting the sample water filtered by the membrane filter section can be given.

In the FI measuring device, the pressurizing device may be, for example, a pressurizing device that includes a compressor and a pressure regulating valve and pressurizes the inside of the sample water tank by air pressure. In the FI measuring device, one end of the sample water pipe extends to near the bottom of the sample water tank. The membrane filter section has a diameter of 47.
Filter paper having a diameter of 0.45 μm and a diameter of 0.4 mm is loaded as a filter.

In order to measure the FI of the sample water using the FI device, the following procedure is performed: (a) First, a predetermined volume, for example, 20 liters of sample water is put into the sample water tank. (B) Then, the inside of the sample water tank is pressurized to a predetermined pressure, for example, a pressure of 2.1 kg / cm ² G by the pressurizing device, to start the flow of the sample water to the membrane filter unit,
(c) The filtered water filtered in the membrane filter section is collected by the cylinder, and (d) the time T ₁ required until 500 ml of the filtered water accumulates in the cylinder after starting the water flow.
(Sec) was measured, and (d) at 15 minutes after the start of water flow, collection of filtered water was started again.
The time T ₂ required to accumulate ml was measured, and (e) the following formula (I) was obtained from T ₁ and T _2.

FI can be obtained according to the procedure of calculating FI according to FI = (1−T ₁ / T ₂ ) × 100/15.

The water quality standard of the feedwater in the reverse osmosis filtration device 4 can be determined according to the type of the reverse osmosis membrane provided in the reverse osmosis filtration device 4. For example, in a reverse osmosis filtration device using a commercially available cellulose acetate hollow fiber reverse osmosis membrane (Holosep (registered trademark) manufactured by Toyobo Co., Ltd.) as the reverse osmosis membrane, the water quality standard of the feed water is usually FI ≦ 4 pH = 3 to 8 Residual chlorine concentration = 0.1 to 1.0 μg / liter Residual iron + residual manganese concentration ≦ 0.1 mg / liter. Therefore, when a reverse osmosis membrane device having the reverse osmosis membrane is used as the reverse osmosis membrane device 14 in the reverse osmosis filtration device 4, the oxidized raw water obtained in the oxidation tank 2 satisfies the water quality standard. The ratio of “partially oxidizing the polyvalent metal ion” can be determined.

Further, in the oxidation tank 2, the ratio of the polyvalent metal ion to be oxidized and removed to the entire polyvalent metal ion in the raw water is changed according to the concentration of the polyvalent metal ion in the raw water. Can be. For example, when the polyvalent metal ion concentration in the well water is high, the ratio of the polyvalent metal ion oxidized and removed in the oxidation tank 2 is increased to reduce the load applied to the reverse osmosis filtration device 4. Is preferred. On the other hand, when the concentration of polyvalent metal ions in the well water is low, the load on the oxidation tank 2 can be reduced by reducing the proportion of the polyvalent metal ions oxidized and removed in the oxidation tank 2. it can. In addition, even when the reverse osmosis membrane in the reverse osmosis filtration device 4 withstands a high concentration of polyvalent metal ions and has a high removal rate of the polyvalent metal ions, the polyvalent metal that is oxidized and removed in the oxidation tank 2 is removed. The proportion of ions can be reduced.

As described above, in the oxidizing tank 2, a part of the polyvalent metal ions in the well water is oxidized, so that the oxidized raw water contains the polyvalent metal ions and the polyvalent metal ions by oxidation. And the resulting solids. Also,
In some cases, the oxidized raw water contains an unreacted oxidizing agent, that is, a residual oxidizing agent.

Here, the polyvalent metal includes a metal having a valence of 2 or more, and the polyvalent metal ion includes a general metal ion having a valence of 2 or more.

Specific examples of the polyvalent metal include 2A group, 2B group, 3B group, 4B group, and 5B group in the long period type periodic table.
Metals belonging to any one of Group 3B and Group 6B, and Groups 3A to 7A, 8 and 1B in the long period type periodic table
Transition metals belonging to the group can be given. As the polyvalent metal ion, specifically, the 2A group, 2B
Metal ions, which are divalent or higher valent ions of typical metals belonging to any of Group 3, 3B, 4B, 5B, and 6B, and transitions belonging to Groups 3A to 7A, 8 and 1B A transition metal ion which is a divalent or higher ion of a metal can be given.

The typical metal ions include, for example, magnesium ion, calcium ion, aluminum ion, zinc ion, mercury ion and the like. On the other hand, as the transition metal ions, iron ions,
Manganese ions, nickel ions, copper ions, cobalt ions, titanium ions, uranium ions, plutonium ions, thorium ions, vanadium ions, molybdenum ions, chromium ions, and the like can be given.

In the case where well water, river water, lake water and long-term stored water stored in a pool or fire prevention water are used as raw water, and purified water for drinking or other uses for living is obtained from this raw water, From the viewpoint of preventing adverse effects on equipment and the like, examples of the polyvalent metal ions to be removed include iron ions and manganese ions, and heavy metal ions such as hexavalent chromium.

When purified water obtained by purifying raw water such as well water is supplied to a customer as tap water using the polyvalent metal-containing water purification device, the purified water is removed by the polyvalent metal-containing water purification device. Examples of the polyvalent metal ion to be used include a manganese ion, an iron ion and a nickel ion. In particular, the polyvalent metal-containing water purification apparatus of the present invention
If it is used as a simple purification device in an emergency or a disaster, it is preferable to change the design to a simple purification device that removes iron ions and manganese ions from raw water.

In the case where the factory wastewater is purified using this polyvalent metal-containing water purification apparatus and discharged to a river, or in the case where the factory wastewater is purified and used as industrial water, this polyvalent metal-containing water purification apparatus is used. The type of polyvalent metal ion to be removed by using the device varies depending on the type of factory that discharges the factory wastewater. Examples of the polyvalent metal ion include copper ion, zinc ion, lead ion, Nickel ion, cobalt ion, iron ion, aluminum ion,
Titanium ions, uranium ions, thorium ions, vanadium ions, molybdenum ions, and the like can be given.

As described above, only a part of the total amount of the polyvalent metal ions is oxidized by the oxidation treatment in the oxidation tank 2 by changing a part of the polyvalent metal ions to a solid content. It is another object of the present invention to reduce the burden of removing polyvalent metal ions from a polyvalent metal-containing liquid by the reverse osmosis filtration device 4. In other words, a part of the polyvalent metal ions in the polyvalent metal-containing liquid is changed to solids by oxidation, and the solids are removed by the solids removing device 3, and the remaining polyvalent metal ions are removed by the reverse osmosis filtration device 4. Elimination is one important aspect of the present invention. The solid content removing device 3 may be omitted depending on the scale of the reverse osmosis filtration device 4 and the polyvalent metal ion removing ability. The polyvalent metal-containing water purification device 1 in which the solid content removing device 3 is omitted is also an aspect of the present invention, and will be described later.

In order to fulfill the above function, the oxidizing tank 2 is provided with a raw water supply means for supplying raw water such as well water into the oxidizing tank 2, for example, a well water supply pipe 6, and a hypochlorous acid An oxidizing agent supply means for supplying an oxidizing agent such as a sodium solution, for example, an oxidizing agent supply pipe 7;
That is, the concentrated water return pipe is connected to the raw water partially oxidized in the oxidation tank 2, that is, the oxidized raw water transfer pipe 8 for transferring the oxidized raw water to the solid content removing device 3.

In the oxidation tank 2, since the polyvalent metal in the well water is partially oxidized by mixing the well water, the oxidizing agent, and the concentrated water, it is desired that the well water be sufficiently mixed. Usually, the stirring in the oxidation tank 2 is sufficiently performed by the supply of the concentrated water. However, in some cases, a forced stirring device may be provided in the oxidation tank 2.

The scale of the oxidation tank 2 is appropriately determined according to the amount of purified water to be obtained by the polyvalent metal-containing water purification device 1. In this example, the oxidation tank 2 has a capacity of 300 liters.

Generally speaking, since the oxidizing tank oxidizes raw water, raw water supply means for supplying raw water into the oxidizing tank is provided. In FIG. 1, the well water supply means corresponds to raw water supply means.

In this oxidizing tank, the type of oxidizing agent and the type of oxidizing agent depend on the type of raw water, the type of polyvalent metal ions contained in the raw water, and the content of polyvalent metal ions contained in the raw water. The amount, oxidation conditions and the like are determined appropriately. When water is supplied from well water, river water, lake water, or the like as raw water, oxidizing agents to be fed into the oxidation tank include, in addition to the sodium hypochlorite, potassium hypochlorite, ozone, and oxygen. , Air, chlorine, potassium permanganate, manganese dioxide and the like.

The solid content removing device 3 includes a pump P for forcibly discharging the liquid in the oxidation tank 2 from the raw water transfer pipe 8 for oxidation treatment,
A discharge liquid pipe for sending out the liquid discharged by the pump P, a flow path switching means provided in the middle of the discharge liquid pipe, for example, a three-way cock C, and a liquid switched into the oxidation tank 2 by the three-way cock C Pipe 10, a pre-filter 10 for filtering the oxidized raw water coming through the three-way cock C, an activated carbon filter 11 for performing an activated carbon treatment on the oxidized raw water passing through the pre-filter 10, and an activated carbon filter It has a filtration membrane device for removing solids in the raw oxidized water that has passed through 11, for example, a hollow fiber filtration device 12 provided with a hollow fiber membrane such as a so-called PEPA membrane.

The pre-filter 10 is provided for the purpose of preventing the activated carbon filter 11 and the hollow fiber filtration device 12 connected to the latter stage of the solid content removing device 3 from being clogged by the solid content in the raw water for oxidation treatment. ing.
The pre-filter 10 is formed by winding a water-resistant thread such as a cotton thread, a polypropylene thread, a nylon thread, a polyester thread, or a polyethylene thread, or a metal wire such as a stainless wire around a porous or water-permeable core. And a wire mesh filter formed by winding a stainless wire mesh into a cylindrical shape, and a sintered filter formed from a porous sintered body such as stainless steel and ceramics. The pore size of the front filter 10 is:
A range of about 1 to 100 μ is preferable.

The activated carbon filter 11 is composed of an organic substance such as humic acid in the raw water for oxidation treatment, a substance causing odor,
And a function of removing coloring substances and the like.

The activated carbon used in the activated carbon filter 11 is not particularly limited. Specific examples of the activated carbon include powdered activated carbon, granular activated carbon, fibrous activated carbon produced from various natural fibers and synthetic fibers, and various activated carbons. Various forms such as activated carbon fibers in which activated carbon is dispersed in fibers and synthetic fibers can be given.

As the activated carbon filter 11 using powdered, particulate, or fibrous activated carbon as the activated carbon, an activated carbon filter having a form in which powdered, particulate, or fibrous activated carbon is filled in a cylindrical container is used. Can be mentioned.

As the activated carbon filter 11 using fibrous activated carbon or activated carbon fiber, the fibrous activated carbon or activated carbon fiber is processed into a mat shape, a woven fabric shape, or a non-woven fabric shape.
Activated carbon filters which are wound in a cylindrical shape as required and loaded in a cylindrical container can be mentioned.

The hollow fiber filtration device 12 has a function of removing a part of polyvalent metal ions in raw water by removing fine particles of polyvalent metal oxide generated by oxidation in the oxidation tank 2.

As the hollow fiber filtration device 12, for example, a bundle of many hollow fiber membranes is inserted and arranged in a cylindrical case, and a thermosetting resin such as an epoxy resin or a urethane resin is injected into both ends of the case. And then cured to form a potting portion.

In the hollow fiber filtration device 12, oxidized raw water is introduced from one end of the case to flow through the hollow portion of the hollow fiber membrane, and passes through the hollow fiber membrane from inside the hollow fiber membrane to outside the hollow fiber membrane. The filtrate obtained can be taken out as primary purified water. Conversely, it is also possible to flow the oxidized water from outside the hollow fiber toward the inside of the hollow fiber membrane. Here, “primary purified water” refers to the oxidized raw water from which solids have been removed in the solids removal device 3. In the hollow fiber membrane filtration device 12, there is provided a drain vent passage for discharging a concentrated liquid that has passed from one end opening of the hollow fiber membrane to the other end opening and has contained a large amount of solid content. Is preferred.
If the drain passage is provided, the rate of increase of the solid content on the hollow fiber membrane surface does not need to be increased, so that the life of the hollow fiber filtration device 12 can be extended.

In order to prolong the life of the hollow fiber filtration device 12 and further the solid content removing device 3, it is preferable that one or both of a back-flush device and a flushing device for the hollow fiber membrane are attached. Here, "backwashing" refers to an operation of flowing water through the hollow fiber membrane in a direction opposite to the flow direction of raw water during filtration to remove dirt attached to the membrane surface on the raw water supply side. In the specification, this is sometimes referred to as “backwashing”. On the other hand, “flushing” refers to an operation of washing the membrane surface by flowing water at a high flow rate along the membrane surface on the raw water supply side of the hollow fiber membrane.

Hereinafter, an example of the hollow fiber filtration device 12 provided with the drain drainage channel and the backwash device will be described with reference to the drawings. FIG. 4 schematically shows the configuration of the hollow fiber filtration device 12.

As shown in FIG. 4, the hollow fiber filtration device 12 includes a pair of hollow fiber membrane units 12A and 12B filled with the PEPA membrane. The hollow fiber membrane units 12A and 12B are connected in parallel.

The hollow fiber membrane units 12A and 12B
Are substantially cylindrical cases 121 having both ends opened.
It has. The inside of the case 121 is filled with a PEPA film (not shown), and both ends of the case 121 are potted with a thermosetting resin such as an epoxy resin or a polyurethane resin. Is fixed inside. Both ends of the PEPA film are open.

In the example shown in FIG. 4, cylindrical caps 122 and 123 each having an open end are attached to both ends of the case 121, respectively. Of the caps 122 and 123, the cap mounted on the upstream side of the case 121, that is, on the side near the activated carbon filter 11, is the cap 122, and the end of the case 121 opposite to the end on which the cap 122 is mounted. The cap attached to the section is the cap 123.

The case 12 of the hollow fiber membrane unit 12A
A pair of primary purified water outlet pipes 124 for taking out permeated water, that is, primary purified water, is provided near both ends of the hollow fiber membrane unit 1, and a pair of primary purified water for taking out primary purified water is provided near both ends of the case 121 of the hollow fiber membrane unit 12B. Purified water outlet pipe 1
25 are provided.

One of the pair of primary purified water outlet pipes 124 and one of the pair of primary purified water outlet pipes 125 are connected by a line 126, and the other of the pair of primary purified water outlet pipes 124 and The pair of primary purified water outlet pipes 125
Are connected to each other by a pipe 127.

The pipe 126 and the pipe 127 further define
They are connected by a permeate extraction line 128. One end of the permeated water extraction pipe 128 is connected to a pipe 126, and the other end of the permeated water extraction pipe 128 is connected to a transfer pipe 13 described later. An on-off valve 12 </ b> G is interposed between the transfer pipe 13 and the intersection of the permeate extraction pipe 128 with the pipe 127.

In the hollow fiber membrane filtration device 12 shown in FIG. 4, the oxidized raw water introduction pipe 12a for introducing the oxidized raw water filtered by the activated carbon filter 11 into the pair of hollow fiber membrane units 12A and 12B. It has. The oxidized raw water introduction pipe 12a is bifurcated on the way, and each of the oxidized water introduction pipes 12a is connected to a cap 122 in each of the hollow fiber membrane unit 12A and the hollow fiber membrane unit 12B. It is connected. An on-off valve 12C is interposed in the vicinity of the hollow fiber membrane unit 12A in the oxidized raw water introduction pipe 12a, and an on-off valve 12D is provided in the vicinity of the hollow fiber membrane unit 12B in the oxidized raw water introduction pipe 12a. It is interposed.

The cap 123 provided in the hollow fiber membrane unit 12A has a drain drain pipe 12 for draining the concentrated liquid.
The hollow fiber membrane unit 12B is provided with a drain port 12b ″ for draining the concentrated liquid. The drain port 12b ″ is provided in the cap 123 of the hollow fiber membrane unit 12B.
b ′ and the drain pipe 12b ″ are combined into one drain pipe 12b on the way.

An on-off valve 1 is provided near the cap 123 of the hollow fiber membrane unit 12A in the drain pipe 12b '.
An opening / closing valve 12F is interposed in the vicinity of the cap 123 of the hollow fiber membrane unit 12B in the drain pipe 12b ″.

As the hollow fiber membrane loaded in the hollow fiber membrane units 12A and 12B, for example, so-called PEP
A film can be mentioned. The PEPA film has the following formula (I)

Embedded image (However, in the formula (I), R ¹ and R ^{2 each} have 1 to 5 carbon atoms.
Is a lower alkyl group. R ¹ and R ² may be the same or different from each other. R ¹ and R ²
Examples thereof include a methyl group, a propyl group, a butyl group, a pentyl group and the like. In the present invention,
R ¹ and R ² are preferably methyl groups), and a polyarylate (A) having a repeating unit represented by the following formula (II):

Embedded image (However, in the formula (II), R ³ and R ^{4 each} have 1 to 5 carbon atoms.
Is a lower alkyl group. R ³ and R ⁴ may be the same or different. R ³ and R ⁴
Examples thereof include a methyl group, a propyl group, a butyl group, a pentyl group and the like. In the present invention,
Preferably, R ³ and R ⁴ are methyl groups. And / or a polysulfone having a repeating unit represented by the following formula:
(III)

Embedded image And a polyether sulfone (B) having a repeating unit represented by the following formula:

The molecular weight of the polyarylate represented by the formula (I) is preferably in the range of about 20,000 to 50,000.

As the polyarylate, a polyarylate appropriately synthesized by polycondensation of a dihydric phenol and an aromatic dicarboxylic acid may be used, or a commercially available product may be used. Commercially available products include a product sold under the trade name "U-Polymer" by Unitika, a product sold under the trade name "APE" by Bayer, and a product sold under the trade name "DUREL" by Celanese Corporation. And products sold by DuPont under the trade name "Arylon".

The polysulfone having a repeating unit represented by the formula (II) preferably has a molecular weight of about 20,000.
~ 40,000.

As the polysulfone, an appropriately synthesized polysulfone may be used, or a commercially available product may be used. As a commercially available product, a product manufactured by Union Carbide Co., Ltd., which is sold as a product name “P-3500” can be mentioned.

The molecular weight of the polyether sulfone represented by the formula (III) is preferably from about 20,000 to about 40,000.
000.

As the polyether sulfone, an appropriately synthesized polyether sulfone may be used, or a commercially available product may be used. Examples of commercially available products include Sumitomo Chemical Industries, Ltd. products sold under the trade name "Sumika Excel PES".

In the PEPA membrane, the mixing weight ratio (A / B) of the polyarylate (A) and the polysulfone and / or the polyethersulfone (B) is usually 0.1 to 10%.
And the range of 0.3 to 4 is preferable.

The PEPA film usually has a fibril structure, that is, a network structure having through holes communicating in the radial direction, that is, the thickness direction of the film, as a main structure.

The PEPA membrane is formed, for example, by a wet spinning method in which a stock solution obtained by dissolving the polymer alloy in an appropriate solvent is extruded from a double-tube spinneret into a coagulation bath, which is a bath of a coagulation solution, to coagulate. Can be manufactured.

The solvent used for dissolving the polymer alloy in the preparation of the spinning solution is, for example, any of the good solvents of the polyarylate (A) and polysulfone and / or polyethersulfone (B). Solvents can be mentioned, and specific examples thereof include polar organic solvents. Examples of the polar organic solvent include n
-Methylpyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMA), tetrahydrofuran (THF), dioxane, morpholine and the like.

The total of the polymer concentration in the spinning solution, that is, the concentration of polyarylate (A) and the concentration of polysulfone and / or polyethersulfone (B) is usually 10 to 25% by weight, preferably 12 to 20% by weight. %.

As the coagulating liquid, a solvent which is a poor solvent for the hydrophobic polymer and which is miscible with the good solvent used in the preparation of the spinning dope can be used. Specific examples of such a solvent include water, lower alcohols, lower ketones, and a mixed solvent of the same polar organic solvent and water as used for preparing the spinning dope. Can be mentioned.

As the coagulating liquid, one kind selected from the group consisting of water, a lower alcohol, a lower ketone, and a mixed solvent of a polar organic solvent and water similar to those used for preparing a spinning dope is used. May be used alone, or a mixture of two or more solvents selected from the group may be used. Further, one or more solvents selected from the group,
A mixture of the hydrophobic polymer used for the preparation of the spinning solution with a good solvent can also be used as the coagulating solution.

Various additives such as a swelling agent such as potassium chlorate may be added to the spinning solution.

When spinning a hollow fiber membrane using the double-tube spinneret, it is preferable to discharge either air or core liquid from the inner tube of the double-tube spinneret. As the core liquid, for example, a mixture of a good solvent and the poor solvent used for preparing the spinning dope can be used. The composition of the core liquid may be the same as the composition of the coagulating liquid, or may be different.

In the hollow fiber filtration device 12, an on-off valve 12C, an on-off valve 12D, an on-off valve 12E, an on-off valve 12F,
The on-off valve 12G corresponds to a backwashing device in a preferred embodiment of the hollow fiber filtration device 12. The drain pipe 12 b ′ and the drain pipe 12 b ″ correspond to a drain pipe in a preferred embodiment of the hollow fiber filtration device 12.

When filtering the oxidized raw water in the hollow fiber filtration device 12, the on-off valve 12C, the on-off valve 12
D and the on-off valve 12G are fully opened, and the on-off valve 12E and the on-off valve 12F are fully closed or half-opened.

In the above state, the raw water introduced from the oxidized raw water introduction pipe 12a is supplied to the hollow fiber membrane unit 12
Through the caps 122 at A and 12B, it flows into the hollow portion of the hollow fiber membrane from one end opening of the hollow fiber membrane. Part or all of the oxidized raw water flowing into the hollow portion of the hollow fiber membrane permeates the hollow fiber membrane, thereby removing solids such as polyvalent metal oxides in the oxidized raw water. On the other hand, when the on-off valve 12E and the on-off valve 12F are half-opened, the remainder of the oxidized raw water that has not passed through the hollow fiber membrane is discharged as a concentrate from the other end opening of the hollow fiber membrane. Is done.

The oxidized raw water from which solids have been removed in the hollow fiber membrane units 12A and 12B, ie, the primary purified water, is the primary purified water outlet pipe 124 in the hollow fiber membrane unit 12A and the primary purified water in the hollow fiber membrane unit 12B. From the water outlet pipe 125, the hollow fiber membrane units 12A and 1
It is taken out of 2B. Then, the primary purified water is supplied to the reverse osmosis filtration device 4 via a transfer line 13 such as a line 126, a line 127, a line 128, and a hose.

On the other hand, the concentrated liquid discharged from the other end opening of the hollow fiber membrane is mixed with the hollow fiber membrane units 12A and 12A.
B through the cap 123 and the drainage line 12
b ', drain drain line 12b ", and drain drain line 1
It is discharged to the outside of the hollow fiber filtration device 12 through 2b.
The concentrated liquid discharged to the outside of the hollow fiber filtration device 12 may be discharged as wastewater through the drain pipe 12b. Alternatively, the end of the drain pipe 12 b may be connected to the water supply line 5 to return the concentrated liquid to the oxidation tank 2.

Next, the procedure for back washing the hollow fiber membrane in the hollow fiber membrane filtration device 12 shown in FIG. 4 will be described.

In the hollow fiber membrane filtration device 12, the hollow fiber membrane provided in the hollow fiber membrane unit 12B is backwashed by the primary purified water that has passed through the hollow fiber membrane unit 12A, or the hollow fiber membrane unit 12B has passed through the hollow fiber membrane unit 12B. The hollow fiber membrane provided in the hollow fiber membrane unit 12A is back-washed with the primary purified water.

Hereinafter, the case where the hollow fiber membrane provided in the hollow fiber membrane unit 12B is back-washed with the primary purified water that has passed through the hollow fiber membrane unit 12A will be described as an example.

In this case, the on-off valves 12C and 12F are fully opened, and the remaining on-off valves,
D, the on-off valve 12E, and the on-off valve 12G are fully closed.

In this state, the oxidized raw water supply line 1
When the oxidized raw water is supplied from 2a, the oxidized raw water is supplied to the hollow fiber membrane unit 1 from the open / close valve 12C which is fully opened.
It flows into the hollow part from the one end opening part of the hollow fiber membrane through the cap 122 in 2A.

Since the on-off valve 12E interposed in the drain pipe 12b 'is closed, the oxidized raw water is
The entire amount of the water passes through the hollow fiber membrane in the hollow fiber membrane unit 12A and becomes the primary purified water as the primary purified water outlet pipe 12
4 flows out of the hollow fiber membrane unit 12A.

Since the on-off valve 12G is fully closed, the primary purified water flowing out of the primary purified water outlet pipe 124 in the hollow fiber membrane unit 12A is supplied to the pipe 126, the pipe 127, and the hollow fiber membrane unit. 12B through the primary purified water outlet pipe 125, the hollow fiber membrane unit 12B
Flows into the case 121.

The primary purified water flowing into the case 121 of the hollow fiber membrane unit 12B flows from the outside of the hollow fiber membrane of the hollow fiber membrane unit 12B toward the hollow portion of the hollow fiber membrane.

The dirt such as solids accumulated in the hollow portion of the hollow fiber membrane is washed away by the primary purified water flowing into the hollow portion. Thereby, the hollow fiber membrane is back-washed.

Since the on-off valve 12F is fully opened, the primary purified water containing dirt accumulated in the hollow portion passes through the on-off valve 12F, the drain drain line 12b ″, and the drain drain line 12b. It is discharged outside the hollow fiber membrane filtration device 12.

When back washing the hollow fiber membrane unit 12A, the on-off valves 12D and 12E are fully opened, and the remaining on-off valves, ie, on-off valves 12C, 12F, and 1F are opened.
The oxidized raw water may be supplied from the oxidized raw water supply pipe 12a with the 2G fully closed.

Next, the reverse osmosis filtration device 4 will be described in detail.

The reverse osmosis filtration device 4 in this example includes three reverse osmosis membrane devices 14. Each reverse osmosis membrane device 14,
A reverse osmosis membrane housed in a cylindrical body, further comprising an inlet pipe 15 for introducing primary purified water, a permeate outlet pipe 16 from which permeate filtered by the reverse osmosis membrane is led, and the reverse pipe A concentrated water outlet pipe 17 from which the concentrated water in which the primary purified water is concentrated by the permeable membrane is led out.

Hereinafter, an example of the reverse osmosis membrane device 14 will be described with reference to the drawings. FIG. 5 shows a cross section of the reverse osmosis membrane device 14 cut along the longitudinal direction.

The reverse osmosis membrane device 14 shown in FIG. 5 comprises a substantially cylindrical pressure tube 141 having both ends opened,
End plates 142 and 143 for covering the openings at both ends in a watertight manner.
And Here, of the end plates 142 and 143, the upstream end plate is the end plate 142, and the downstream end plate is the end plate 143.

The reverse osmosis membrane 1 is provided inside the pressure-resistant tube 141.
40 are accommodated. The reverse osmosis membrane 140 is an external pressure type hollow fiber membrane made of cellulose acetate. The reverse osmosis membrane 140
Both ends of the potting portion 140 are hardened in a substantially cylindrical shape with a thermosetting resin such as an epoxy resin or a polyurethane resin.
a and 140b are formed. The potting portion 140a is a potting portion facing the end plate 142, and the potting portion 140b is a potting portion facing the end plate 143. A gap is formed between the outer peripheral surface of the potting portion 140a and the inner wall surface of the pressure-resistant tube 141. On the other hand, since the outer peripheral surface of the potting 140b is in close contact with the inner wall surface of the pressure-resistant tube 141, the potting portion 1
No water leaks from between 40b and the inner wall surface of pressure-resistant tube 141. In the reverse osmosis membrane 140, the end on the side where the potting portion 140a is formed is filled and closed with a thermoplastic resin forming the potting portion 140a, and the end on the side where the potting portion 140b is formed is The potting portion 140b is cut so as to be parallel to the end plate 143, and an opening is formed.

The introduction tube 15 penetrates the center of the bundle of the end plate 142 and the reverse osmosis membrane 140, and the tip is embedded in the potting portion 140b. A large number of pores are formed in a portion of the introduction tube 15 that penetrates the center of the bundle of the reverse osmosis membrane 140. The portion of the introduction tube 15 where a large number of pores are formed is indicated by a broken line in FIG.

The permeated water outlet pipe 16 is provided upright at the center of the end plate 143, and extends in a direction away from the potting portion 140b. On the other hand, the concentrated water outlet pipe 1
Reference numeral 7 stands upright at the peripheral edge of the end plate 142 and extends in a direction away from the potting portion 140a.

In the reverse osmosis membrane device 14, the primary purified water introduced into the cylinder from the introduction pipe 15 is supplied to the reverse osmosis membrane 14.
It is filtered by a reverse osmosis membrane such as 0 to be separated into permeated water and concentrated water. The permeated water is discharged from the permeated water discharge pipe 16, while the concentrated water is discharged from the concentrated water discharge pipe 17.
By this reverse osmosis membrane, the concentration of polyvalent metal ions in the primary purified water is reduced to a reference value or less specified by the Water Supply Law. Specifically, by the treatment with the reverse osmosis membrane, the iron ion concentration in the primary purified water is usually reduced to 0.3 mg / liter or less, and the manganese ion concentration is usually 0.1 mg / liter.
It is reduced to less than 05 mg / liter.

As described above, as an example of the reverse osmosis membrane device 14, a reverse osmosis membrane device having a hollow fiber membrane formed of cellulose acetate has been described.

The reverse osmosis membrane used in the reverse osmosis membrane device 14 is not limited to the hollow fiber membrane formed from the cellulose acetate. As the reverse osmosis membrane used in the reverse osmosis membrane device 14, for example, a low pressure reverse osmosis membrane used under a pressure in a range of about 1 to 10 kg / cm ² ,
An example is a medium pressure reverse osmosis membrane used under a pressure of about 45 kg / cm ² . As the reverse osmosis membrane,
The asymmetric membrane in which the porous support layer and the dense surface layer are provided, and the support layer and the surface layer are formed of the same material, and the surface of the porous support layer, of a material different from the support layer A composite film having a surface layer formed thereon can be given.

Examples of the material of the asymmetric membrane include cellulose esters such as cellulose acetate and cellulose acetate butyrate, polyamides such as polyetheramide, polyamidecarboxylic acid, polypiperazineamide, and aromatic polyamide, modified polyacrylonitrile, and polyethyleneimine. Various polymers such as condensates and modified polyethyleneimines such as polyethyleneimine-acid chloride, polybenzimidazole, and sulfonated polymers such as sulfonated phenylene oxide, sulfonated polyfurfuryl alcohol, and sulfonated polysulfone can be given. .

Examples of the composite membrane include polysulfone, polyethersulfone, polyarylate, a polymer alloy of polyarylate and polyethersulfone, a polymer alloy of polyarylate and polyethersulfone, and a polymer alloy of polyarylate, polysulfone and polyethersulfone. A film in which a surface layer of polyamide, polyetheramide, or the like is formed on the surface of a porous film formed of a material selected from alloy, polyamide, or the like can be given.

The asymmetric membrane and the composite membrane can take various forms such as a hollow fiber membrane, a tubular membrane, a capillary membrane, a spiral membrane, and a flat membrane. Incidentally, the tubular membrane usually has a diameter of 10 mm or more, and the capillary membrane usually has a diameter in the range of 1 to 10 mm. The hollow fiber membrane, the tubular membrane, and the capillary membrane include an external pressure type and an internal pressure type, respectively.

In the example shown in FIG. 1, three reverse osmosis membrane devices 14 are connected in series. That is, the concentrated water outlet pipe 17 in the first reverse osmosis membrane device 14 is connected to the inlet pipe 15 in the second reverse osmosis membrane device 14, and the concentrated water outlet tube 17 in the second reverse osmosis membrane device 14 is The concentrated water outlet pipe 17 of the third reverse osmosis membrane device 14 is connected to the water supply line 5. On the other hand, the first, second, and third
Are connected to a permeate delivery pipe 18 such as a hose.

Therefore, the concentrated water discharged from the concentrated water outlet pipe 17 in the first reverse osmosis membrane device 14 is supplied to the second reverse osmosis membrane device 14 from the introduction pipe 15 in the second reverse osmosis membrane device 14. The concentrated liquid discharged from the concentrated water outlet pipe 17 in the second reverse osmosis membrane apparatus 14 is supplied from the inlet pipe 15 in the third reverse osmosis membrane apparatus 14 to the third reverse osmosis membrane apparatus 1.
4 and discharged from the concentrated water outlet pipe 17 in the third reverse osmosis membrane device 14 is supplied to the water supply line 5. On the other hand, permeated water discharged from the permeated water outlet pipe 16 of the first reverse osmosis membrane device 14, permeated water discharged from the permeated water outlet pipe 16 of the second reverse osmosis membrane device 14, and third reverse osmosis The permeated water discharged from the permeated water outlet pipe 16 of the membrane device 14 is collected and distributed to a required portion by the permeated water delivery pipe 18.

In the case where the reverse osmosis filtration device 4 has a plurality of reverse osmosis membrane devices 14 as described above,
4 are connected in series, that is, when the concentrated water outlet pipe 17 in one reverse osmosis membrane device 14 is connected to the introduction pipe 15 in the next reverse osmosis membrane device 14, the reverse osmosis membrane device 14 is connected. When connected in parallel, that is, the transfer piping 13
The reverse osmosis membrane device 1 is connected to the inlet pipe 15 of each reverse osmosis membrane device 14 and the concentrated water outlet pipe 17 of each reverse osmosis membrane device 14 is integrated into one and connected to the water supply line 5.
4, the flux of the primary purified water can be increased, so that the concentration polarization in the reverse osmosis membrane device 14 can be reduced. Therefore, when the FI of the primary purified water is small, if the reverse osmosis membrane device 14 is connected in series, the generation of fouling and scale on the membrane surface of the reverse osmosis membrane provided in the reverse osmosis membrane device 14 can be suppressed. it can.
However, when the FI of the primary purified water is high, a connection method of connecting the reverse osmosis membrane devices 14 in parallel is preferable.

In the reverse osmosis filtration device 4, it is advantageous that the reverse osmosis membrane can be prolonged by periodically performing one or both of the reverse washing and the flushing. In the reverse osmosis filtration device 4, it is particularly preferable to carry out flushing for removing dirt and the like on the surface by flowing low-pressure, high-flow-rate water along the surface of the reverse osmosis membrane.

The water supply line 5 is also a concentrated liquid returning means for returning the concentrated liquid separated by the reverse osmosis filtration device 4 to the oxidation tank 2. The concentrated water contains the polyvalent metal ions separated by the reverse osmosis membrane and the residual oxidizing agent that has not been consumed in the oxidation treatment until the primary purified water reaches the reverse osmosis filtration device 4. Therefore, it is preferable to return the concentrated water containing the residual oxidant to the oxidation tank 2 because the amount of the new oxidant supplied to the oxidation tank 2 can be reduced.

According to the polyvalent metal-containing water purification apparatus 1 having the above-described configuration, a part of the polyvalent metal ions contained in the polyvalent metal-containing water is oxidized in the oxidation tank 2. As a result, an oxide of the polyvalent metal is generated as a solid content in the oxidation tank 2. Raw water containing solids, which are oxides of polyvalent metals, and polyvalent metal ions is sent from the oxidation tank 2 to the solids removing device 3 as raw water for oxidation treatment.

In the water supply line 5, a flow rate adjusting device for adjusting the flow rate is interposed.

The solids removing device 3 removes polyvalent metal oxides present in the raw water for oxidation treatment and other solids present from the beginning, and discharges the primary purified water. In addition, the concentrated water containing the solid content is discharged from the drain passage.
By discharging this concentrated water, P
The deposition rate of the deposition amount of the solid content that adheres to the EPA film is reduced. Therefore, the life of the solid content removing device 3 can be prolonged by providing the drain drain channel. When one or both of the backwashing device and the flushing device are installed in the solid content removing device 3, the solid content removing device 3 is periodically backwashed and / or flushed to remove the solid content. The life of the device 3 can be extended.

The primary purified water discharged from the solid content removing device 3 is sent to the reverse osmosis filtration device 4. In the reverse osmosis filtration device 4, polyvalent metal ions in the primary purified water are removed. Also, the solid content remaining in the primary purified water is removed by the reverse osmosis membrane. The permeated water separated by the reverse osmosis membrane is supplied to a predetermined location, for example, for drinking water. On the other hand, the concentrated water separated by the reverse osmosis filtration device 4 contains a high concentration of polyvalent metal ions and a residual oxidizing agent. When this concentrated water is returned to the oxidation tank 2, the oxidation treatment of the polyvalent metal-containing water is performed in the oxidation tank 2 by the oxidizing agent in the concentrated water together with the newly added oxidizing agent. In this oxidation treatment, since the residual oxidant in the concentrated water is reused, the amount of the oxidant newly supplied to the oxidation tank 2 can be reduced. In other words, the oxidant supplied to the oxidation tank 2 is theoretically completely consumed by returning the concentrated water to the oxidation tank 2.

In the apparatus shown in this example, since the reverse osmosis filtration device 4 and the solids removal device 3 are combined, the burden on the reverse osmosis filtration device 4 for removing metal ions is reduced. The service life of the reverse osmosis filtration device 4 can be lengthened, and the life of the device can be lengthened as a whole. Since the reverse osmosis membrane and the filtration membrane for removing solids can be backwashed and / or flushed, in the apparatus shown in this example, by performing regular backwashing and / or flushing, the length of the apparatus can be reduced. Life can be extended.

In another embodiment of the present invention, the solid content removing device is omitted. If the solids removing device is omitted, the entire device can be downsized accordingly. However, since there is no solid content removing device, the burden of removing polyvalent metal ions is imposed on the reverse osmosis filtration device, and there is a possibility that backwashing is often required.

FIG. 2 shows an example of a polyvalent metal-containing water purifying apparatus in which the solid content removing apparatus is omitted. The device shown in FIG.
Except that the front filter 10, the activated carbon filter 11, and the hollow fiber filtration device 12 are not provided, it has the same configuration as the polyvalent metal-containing water purification device shown in FIG.

In FIG. 2, members or devices denoted by the same reference numerals as those in FIG. 1 are the same as the members or devices described in FIG.

In still another embodiment of the polyvalent metal-containing water purifying apparatus according to the present invention, as shown in FIG. 3, between the solids removing apparatus 3 and the reverse osmosis filtration apparatus 14 or the pump shown in FIG. An oxidant removing device 19 is interposed between P and the reverse osmosis filtration device 14.

The oxidizing agent removing device 19 is a device for removing primary purified water discharged from the solid content removing device 3 or discharged from the oxidizing tank 2 in a polyvalent metal-containing water purifying device not provided with the solid content removing device 3. Removing the unreacted residual oxidizing agent contained in each of the oxidized raw water to be treated,
Alternatively, the amount is reduced to a negligible level.

For removing the residual oxidant in the oxidant removing device 19, for example, a neutralization treatment for eliminating or reducing the residual oxidant by neutralization, and the primary purified water or Either or both of the adsorption filtration treatments for removing or reducing the residual oxidizing agent in the oxidized raw water can be employed.

In the oxidizing agent removing apparatus 19 employing the neutralizing treatment, the type and amount of the neutralizing agent are appropriately determined according to the type and amount of the residual oxidizing agent.

For example, when the oxidizing agent charged into the oxidizing tank 2 is chlorine or sodium hypochlorite, sodium hydrogen sulfite can be used as the neutralizing agent.

Oxidizing agent removing apparatus 1 employing adsorption filtration
In the case of 9, the type of the adsorbent filter agent and the device configuration for loading the adsorbent filter agent are appropriately adopted according to the type and amount of the residual oxidant.

For example, when the oxidizing agent charged into the oxidizing tank 2 is chlorine or sodium hypochlorite, an adsorbing agent such as activated carbon can be used as the adsorptive filtering agent. Such an adsorption filter agent is filled in a chamber, a cylindrical case, a container, or the like through which the primary purified water or the raw water for oxidation treatment passes, or in a form such as loaded in a filter cloth.
used.

In the polyvalent metal-containing water purifying apparatus having the oxidizing agent removing device 19, the amount of the oxidizing agent remaining in the primary purified water or the amount of the oxidizing agent remaining in the oxidized raw water is determined by the oxidizing removing device 19. Is reduced or reduced to a negligible amount.

However, when the oxidizing agent removing device 19 is used to completely neutralize the oxidizing agent remaining in the primary purified water or completely remove the oxidizing agent remaining in the oxidized raw water, the reverse osmosis is performed. The concentrated water discharged from the membrane device no longer contains the residual oxidizing agent. At that time, the concentrated water containing no residual oxidizing agent is returned to the oxidation tank 2 through the water supply line 5. In addition, the residual oxidizing agent can reduce the damage to the reverse osmosis membrane device and the mechanical equipment that comes into contact with the liquid containing the oxidizing agent. In other words, the adverse effects of the residual oxidizing agent are wiped out, thereby prolonging the life of the device.

Hereinafter, in the purifying apparatus shown in FIG.
Reverse osmosis filtration provided with a solid content removal device 3 having a hollow fiber membrane filtration device 12 provided with a PEPA membrane having a membrane area of 3.6 m ² , and further connected to one Toyobo Co., Ltd. Horosep (registered trademark) HA8130 type. An example in which well water having a content of iron ions of 5.8 mg / liter and a content of manganese ions of 3.0 mg / liter is purified using a purification device including the device 4 will be described.

The supply amount of well water in the purification device is as follows:
In the oxidation tank 2, sodium hypochlorite was used as an oxidizing agent. The hypochlorous acid concentration in the oxidizing tank 2 was determined so that the residual chlorine amount in the oxidizing tank 2 was 50 mg / liter. The processing time in the oxidation tank was 30 minutes.

In the reduction tank 19, sodium hydrogen sulfite was added as an aqueous solution to reduce the residual chlorine concentration to 0.5 mg.
/ Liter concentration.

Further, in the reverse osmosis filtration device 4,
The amount of concentrated water was adjusted so that the recovery rate was 50%.

In the water purification device, the iron ion concentration in the primary purified water derived from the solid content removing device 3 is 0.4
mg / liter, and the manganese ion concentration is 0.2 mg / liter.
Liters. And the residual chlorine amount was 20 mg / liter.

On the other hand, in the purified water having passed through the reverse osmosis filtration device 4, the iron ion concentration was 0.04 mg / liter, and the manganese ion concentration was 0.02 mg / liter. And the residual chlorine amount was 0.5 mg / liter. On the other hand, in the concentrated water, the iron ion concentration is 0.8 mg / liter, and the manganese ion concentration is 0.1 mg / liter.
It was 4 mg / liter. And the residual chlorine amount is 0.5
mg / liter.

Here, the water quality standard value at the time of filing of the present application is such that the iron ion concentration is 0.3 mg / liter or less and the manganese ion concentration is 0.05 mg / liter or less.
Therefore, even when the raw water contains polyvalent metal ions such as iron ions and manganese ions at a high concentration, by treating this raw water with the polyvalent metal-containing water purification device of the present invention, It can be seen that purified water having a water quality far exceeding the water quality standard can be obtained.

[0135]

According to the present invention, the concentrated liquid discharged from the reverse osmosis filtration device and containing the residual oxidant is returned to the oxidation tank to reuse the residual oxidant, and furthermore, the concentrated oxidant is oxidized by the reverse osmosis filtration device. Provided is a small polyvalent metal-containing water purification device capable of efficiently producing permeated water from which polyvalent metal ions have been removed because solids and polyvalent metal ions generated by oxidation treatment in the tank are removed. can do.

According to the present invention, the reverse osmosis filtration device and the solids removing device are combined, and the concentrated liquid containing the residual oxidizing agent is returned to the oxidation tank to reuse the residual oxidizing agent. It is possible to provide a small-sized polyvalent metal-containing water purification device that can be maintained and can efficiently purify the polyvalent metal-containing water.
Further, in the polyvalent metal-containing water purifying apparatus, the sedimentation basin or the sedimentation tank required in the conventional air oxidation method or the like is not required, so that the size can be significantly reduced.

According to the present invention, since the oxidizing agent removing device is provided, the residual oxidizing agent in the primary purified water or the raw oxidized water which has been oxidized in the oxidizing tank is eliminated, or the amount of the residual oxidizing agent is ignored. As a result, the life of the equipment can be prolonged, the purification function can be maintained for a long time, and the water containing polyvalent metals can be purified efficiently. It is possible to provide a small-sized multivalent metal-containing water purifying apparatus that can perform the above.

According to the present invention, it is possible to provide a polyvalent metal-containing water purifying apparatus having a longer purifying function by attaching one or both of a backwashing apparatus and a flushing apparatus.

According to the present invention, it is possible to provide a polyvalent metal-containing water purifying apparatus which achieves a long service life of the solid content removing device by providing a drain drain passage for discarding concentrated water containing solid content. .

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a polyvalent metal-containing water purification device as an example of the present invention.

FIG. 2 is a schematic explanatory view showing a polyvalent metal-containing water purifying apparatus as another example of the present invention.

FIG. 3 is a schematic explanatory view showing a polyvalent metal-containing water purification device as another example of the present invention.

FIG. 4 is a schematic diagram illustrating a configuration of an example of a hollow fiber filtration device including a drain drain channel and a backwashing device.

FIG. 5 is a cross-sectional view showing a cross section of the reverse osmosis membrane device cut along a longitudinal direction.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Polyvalent metal containing water purifier, 2 ... Oxidation tank, 3
... Solid matter removal device, 4 ... Reverse osmosis filtration device, 5
..Water supply line, 6 ... Well water supply pipe, 7 ... Oxidant supply pipe, 8 ... Oxidized raw water transfer pipe, P ... Pump, C ... Three-way cock, 9 ... Reverse Transmission piping, 10
・ Front filter, 11 ・ ・ ・ Activated carbon filter, 12 ・
..Hollow fiber filtration device, 13 ... Transfer piping, 14 ...
Reverse osmosis membrane device, 15 ... inlet, 16 ... permeate outlet, 17 ... concentrated water outlet, 18 ... permeate delivery pipe, 19 ... oxidant removing device, 12A, 12B ...
Hollow fiber membrane unit, 121 ... case, 122, 12
3 ... Cap, 124, 125 ... Primary purified water outlet pipe, 126, 127, 128 ... Pipe, 12C, 1
2D, 12E, 12F, 12G ... open / close valve; 140
··· Reverse osmosis membrane, 140a, 140b ··· potting part, 141 ··· pressure-resistant tube, 142, 143 ··· end plate.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C02F 1/64 C02F 1/64 Z 1/70 1/70 Z

Claims (6)

[Claims] An oxidizing tank for oxidizing a part of polyvalent metal ions contained in raw water, and an oxidized raw water oxidized in the oxidizing tank and containing remaining polyvalent metal ions is subjected to reverse osmosis membrane. A reverse osmosis filtration device for filtering and separating into permeated water and concentrated water; and a water supply line for returning the concentrated water concentrated in the reverse osmosis filtration device to the oxidation tank, wherein the polyvalent metal is provided. Contained water purification device. 2. An oxidation tank for oxidizing a part of polyvalent metal ions contained in raw water, and an oxidizing tank for oxidizing the solids in the oxidized raw water containing residual polyvalent metal ions. A solid content removing device for removing; a reverse osmosis filtration device for filtering the primary purified water from which solid content has been removed by the solid content removing device through a reverse osmosis membrane to separate it into permeated water and concentrated water; A water feed line for returning the concentrated water concentrated by the device to the oxidation tank; 3. An oxidizing tank for oxidizing a part of polyvalent metal ions contained in raw water, and a solid content in the oxidized raw water that is oxidized in the oxidizing tank and contains residual polyvalent metal ions. A solid content removing device for removing, an oxidizing agent removing device for treating the primary purified water from which solid content has been removed by the solid content removing device to remove an oxidizing agent remaining in the primary purified water, A reverse osmosis filtration device that filters the discharged treatment liquid through a reverse osmosis membrane to separate the permeated water and the concentrated water; and a water supply line that returns the concentrated water concentrated by the reverse osmosis filtration device to the oxidation tank. An apparatus for purifying water containing polyvalent metals, comprising: 4. The solid content removing device according to claim 2, further comprising a drain passage for discharging a part of the solid content-containing concentrated liquid produced by the solid content removal. Water purification equipment containing polyvalent metals. 5. The oxidizing agent removing device according to claim 1, wherein the oxidizing agent removing device is a reduction tank for neutralizing a residual oxidizing agent contained in the primary purified water or a filter for adsorbing and filtering the residual oxidizing agent contained in the primary purified water. Item 5. The polyvalent metal-containing water purification device according to any one of Items 3 and 4. 6. The multivalent filter according to claim 1, wherein the filtration device and / or the reverse osmosis filtration device includes one or both of a backwashing device and a flushing device. Metal-containing water purification equipment.