JP2011206750A - Water treatment method and water treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water treatment method and a water treatment apparatus which use a fibrous filtering medium and are good in capturing performance of suspended matter contained in water to be treated.SOLUTION: A coagulant containing an amphoteric electrolytic polymer having a cationic monomer unit of 20-80 mol%, an anionic monomer unit of 5-40 mol% and a nonionic monomer unit of 0-75%, is added to the water to be treated, to coagulate it. Thereafter, the water to be treated, which is coagulated, is made to flow in a filtration treatment means, which has the fibrous filtering medium for capturing the suspended matter in the flowed water to be treated, to be filtered.

Description

The present invention relates to a water treatment method and a water treatment apparatus for water to be treated such as industrial water, city water, well water, river water, lake water, and factory waste water.

As a method of treating treated water such as industrial water, city water, well water, river water, lake water, and factory wastewater, for example, an inorganic flocculant and an anionic polymer flocculant are added to the treated water. There is a method of removing turbidity by sand filtration or pressurized flotation treatment after flocculation treatment such as adsorption or condensation of the turbidity contained in the treated water. However, sand filtration and pressure levitation processing have a problem that the apparatus becomes large.

Here, a filtration device using a fibrous filter body (filter material) has been proposed as a filtration device capable of saving space because a filtration process at a very high filtration rate is possible (Patent Documents 1 to 3). reference). However, the filtration apparatus using the fibrous filter body has a poor ability to capture fine particles. Therefore, when water treatment is performed using this filtration device, a flocculant such as an inorganic flocculant or a polymer flocculant is used, or in order to capture fine particles not captured by this filtration device, further filtration is performed. Although means are provided, there is a problem that the capture performance is insufficient and it is difficult to obtain clear treated water.

JP 2003-265907 A JP 2004-89766 A JP 2007-229658 A

In view of the above-described circumstances, an object of the present invention is to provide a water treatment method and a water treatment apparatus that use a fibrous filter and have good trapping performance for turbidity contained in water to be treated.

As a result of intensive studies to achieve the above object, the present inventors have found that the cationic monomer units 20 to 80 mol% and the anionic monomer unit 5 are filtered before the filtration treatment by the filtration treatment means having a fibrous filter. It was found that the above object was achieved by adding an amphoteric electrolyte polymer having ˜40 mol% and nonionic monomer units of 0 to 75% as a flocculant, and the present invention was completed.

That is, the water treatment method of the present invention comprises an agglomeration containing an ampholyte polymer having 20 to 80 mol% of cationic monomer units, 5 to 40 mol% of anionic monomer units, and 0 to 75% of nonionic monomer units. After the agent is added to the water to be treated and coagulated, the coagulated water to be treated is passed through a filtration means having a fibrous filter that captures turbidity in the water to be treated. And filtering.

Moreover, it is preferable that the said filtration processing means is filled in the filtration tank so that the filter body which has a string-like turbidity capture | acquisition part may have the porosity of the filtration part at the time of water flow to 50 to 95%.

  And before the said filtration process, you may add an inorganic flocculant to to-be-processed water.

Another aspect of the present invention is a reaction tank into which water to be treated is introduced, and a cationic monomer unit 2.
A flocculant containing an amphoteric electrolyte polymer having 0 to 80 mol%, anionic monomer units 5 to 40 mol%, and nonionic monomer units 0 to 75% is introduced in the preceding stage of the reaction vessel or reaction vessel. A flocculant introducing means for adding the flocculant to the water to be treated; and a filtration means for filtering the water to be treated which has been agglomerated in the reaction tank and is provided downstream of the reaction tank. And a filtration means having a fibrous filter for capturing turbidity in the treated water.

Cationic monomer units 20 to 80 mol% and anionic monomer units 5 to 4
By adding a flocculant containing an amphoteric electrolyte polymer having 0 mol% and nonionic monomer units of 0 to 75% to the water to be treated, the turbidity contained in the water to be treated and the amphoteric electrolyte polymer are extremely It is possible to form strong and large flocs (aggregates). Therefore, even when filtration is performed by a filtration means using a fibrous filter, the formed floc has a very high capture rate compared to the case of using a conventional polymer flocculant or inorganic flocculant. Since it is captured by the fibrous filter, treated water with high clarity can be obtained.

It is sectional drawing which shows the structure of a filtration apparatus. It is a principal part enlarged view of a filtration apparatus. It is a figure which shows an example of the turbidity capture | acquisition part of a filtration apparatus. It is a schematic system diagram of the example of a water treatment apparatus. It is a schematic system diagram of the example of a water treatment apparatus.

  Hereinafter, the present invention will be described in detail based on embodiments.

The water treatment method of the present invention comprises a flocculant containing an amphoteric electrolyte polymer having 20 to 80 mol% of cationic monomer units, 5 to 40 mol% of anionic monomer units, and 0 to 75% of nonionic monomer units. Then, after adding to the water to be treated and aggregating the water, the water to be treated which has been agglomerated is passed through a filtration means having a fibrous filter that captures turbidity in the water to be treated. Filtering is performed.

Examples of water to be treated include water containing a humic acid / fulvic acid organic substance, a biological metabolite such as sugar produced by algae, or a synthetic chemical substance such as a surfactant, specifically, industrial water. ,
Examples include, but are not limited to, city water, well water, river water, lake water, and factory wastewater (particularly, biologically treated water obtained by biologically treating wastewater from a factory). The humic substance refers to a corrosive substance generated by the decomposition of plants and the like into microorganisms, and includes humic acid, and the water containing the humic substance is derived from humic substance and / or humic substance. Soluble COD
Contains ingredients, suspended matter and chromaticity components.

And the flocculant added to to-be-processed water has 20-80 mol% of cationic monomer units, 5-40 mol% of anionic monomer units, and 0-75% of nonionic monomer units in this invention. It contains an ampholyte polymer. That is, it is an ampholyte polymer essentially comprising 20 to 80 mol% of cationic monomer units and 5 to 40 mol% of anionic monomer units, and further having 75% or less of nonionic monomer units. Good. Since this copolymer is an electrolyte,
It is soluble in water.

Thus, by adding an amphoteric copolymer having a predetermined ratio of cationic monomer unit and anionic monomer unit as a flocculant, the turbidity of the water to be treated and a very strong and large floc (aggregate) Therefore, as shown in the examples described later, clear treated water can be obtained. When the ratio of the cationic monomer unit is higher than 80 mol% or the ratio of the anionic monomer unit is lower than 5 mol%, the amphoteric characteristics are diminished, and a strong and large floc is formed to obtain a clear treated water. The effect of the present invention cannot be obtained. The amphoteric copolymer having a cationic monomer unit of 20 to 50 mol%, an anionic monomer unit of 5 to 25 mol%, and a nonionic monomer unit of 20 to 75% forms a particularly strong and large floc. This is preferable.

The production method of such an amphoteric electrolyte polymer is not particularly limited, and can be synthesized, for example, by copolymerizing a cationic monomer having a polymerizable group such as a vinyl group, an anionic monomer, or a nonionic monomer. Of course, the cationic monomer unit of the amphoteric electrolyte polymer is composed of this cationic monomer, the anionic monomer unit of the amphoteric electrolyte polymer is composed of the anionic monomer, and the nonionic monomer unit of the amphoteric electrolyte polymer is composed of the nonionic monomer. The A block copolymer or a random copolymer may be used.

The cationic monomer is, for example, a monomer having a functional group such as a primary amine, secondary amine, tertiary amine and acid salts thereof, or a quaternary ammonium group. Specific examples of the cationic monomer include dimethylaminoethyl (meth) acrylate acid salt or its quaternary ammonium salt, dimethylaminopropyl (meth) acrylamide acid salt or its quaternary ammonium salt, diallyldimethylammonium chloride, and the like. It is done. Note that (meth) acrylate represents “acrylate or methacrylate”, and the same applies to (meth) acrylamide and (meth) acrylic acid. Examples of the anionic monomer include (meth) acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and alkali metal salts thereof. Nonionic monomers include (meth) acrylamide, N isopropyl acrylamide, N methyl (NN dimethyl) acrylamide,
Examples include acrylonitrile, styrene, methyl or ethyl (meth) acrylate. Each monomer may be one kind or plural kinds.

The ampholyte polymer may be synthesized by a polymer reaction of a cationic water-soluble polymer, an anionic water-soluble polymer, or a nonionic water-soluble polymer.

The amphoteric electrolyte polymer may be in the form of a powder, a reverse phase emulsion, or an aqueous solution. And the form which adds an amphoteric electrolyte polymer to a to-be-processed water as a coagulant | flocculant is not specifically limited, The to-be-processed water and an amphoteric electrolyte polymer contact, and the suspended matter (SS) contained in a to-be-processed water becomes an amphoteric electrolyte polymer. It is only necessary to form a floc by adsorbing, that is, to perform a coagulation treatment. For example, it is preferable to add a 0.01 to 0.5 mass% aqueous solution of an ampholyte polymer to the water to be treated. Two or more amphoteric electrolyte polymers may be added to the water to be treated.
Moreover, there is no restriction | limiting in particular in the quantity which adds an amphoteric electrolyte polymer to to-be-processed water, However It is preferable to set it as about 0.5-100 mg / L with respect to to-be-processed water. The amount of addition depends mainly on the concentration of organic matter in the water, and varies depending on the quality of the water to be treated.

In addition, an inorganic flocculant may be added to the water to be treated at the time of the flocculation treatment. By adding an inorganic flocculant, it becomes possible to remove minute turbidity and water-soluble turbidity, and the treated water obtained can be clarified. Further, by adding an inorganic flocculant, a stronger floc can be formed by the interaction between the amphoteric electrolyte polymer and the inorganic flocculant than when the amphoteric electrolyte polymer is used alone. The inorganic flocculant may be added before the filtration treatment described later, before or after the amphoteric electrolyte polymer is added to the water to be treated, and may be added simultaneously with the amphoteric electrolyte polymer. It is preferable to add it before the addition of the ampholyte polymer. This is because, by adding an inorganic flocculant, fine flocs are first generated and then an amphoteric electrolyte polymer is added to further increase the flocs, thereby greatly improving the agglomeration efficiency. There are no particular limitations on the inorganic flocculant, and examples thereof include aluminum salts such as sulfate bands and polyaluminum chloride (PAC), and iron salts such as ferric chloride and ferrous sulfate.
Moreover, there is no limitation in particular also in the addition amount of an inorganic flocculant, What is necessary is just to adjust according to the property of the to-be-processed water to process, but about 0.5-10 mg / L in conversion of aluminum or iron with respect to to-be-processed water. It is. Although depending on the properties of the water to be treated, when polyaluminum chloride is used as the inorganic flocculant, when the pH of the water to be treated is about 5.0 to 7.0, the coagulation is optimized and greatly strong. A floc can be formed.

In this way, after adding an amphoteric electrolyte polymer or an inorganic flocculant to the water to be treated and subjecting it to agglomeration treatment such as stirring as necessary, the water to be treated is filtered through the filtration means. . And in this invention, a filtration process means has a fibrous filter body which captures the turbidity in the to-be-processed water passed.

Here, the filtration processing means using the fibrous filter body can save space because it can be filtered at a very high filtration rate, but the trapping performance of fine particles is relatively poor. However, in the present invention, since the agglomeration treatment is performed with the predetermined amphoteric electrolyte polymer before passing through the filtration means, the water to be treated that is passed through the filtration means is turbid and amphoteric electrolyte. A very large and strong floc is formed with the polymer. Therefore, even if it is the filtration process means using a fibrous filter body, since it can capture | acquire favorable, clear treated water can be obtained.

There is no particular limitation on the filtration means, but for example, a filtration body having a string-like (fibrous) turbidity trapping part is filled in the filtration tank so that the porosity of the filtration part when passing water is 50 to 95%. It is preferable that A specific example of such a filtration means is the filtration device shown in FIG. 1 is a cross-sectional view showing the configuration of the filtration device, and FIG. 2 is an enlarged view of a main part of FIG.

As shown in FIG. 1, the filtration device 10 includes a cylindrical filtration tank 11 through which the water to be treated 1 is passed, and a filter body 12 that captures turbidity in the water to be treated. The filter body 12 is a filter tank 1
1 consists of a core 13 connected to both ends in the water flow direction and a string-like turbidity capturing portion 14. Further, at both ends of the filtration tank 11 in the water flow direction, a circular plate 16 made of resin or the like provided with a plurality of holes that allow water to be treated containing turbidity to flow freely is provided. Both ends of the core material 13 are fixed to the center of the core. The turbidity trapping part 14 is provided so that a part of the turbidity trapping part 14 is knitted and fixed to the core member 13 and a so-called loop-like part that is not fixed spreads radially toward the inner wall surface of the filtration tank 11. The filter body 12 spreads over the entire filtration tank 11. For this reason, since the turbidity capture | acquisition part 14 cross | intersects a water flow direction, the turbidity contained in the to-be-processed water 1 can be captured by the turbidity capture | acquisition part 14. FIG. The string-like turbidity capturing portion 14 is a long rectangle (tape).
As shown in the enlarged view of the string-like turbid trap 14 in FIG. 2, a plurality of slits 15 that do not reach the end in the longitudinal direction are provided. By providing the slit 15 in this way, the trapping effect of turbidity is improved.

Here, the filter body 12 is in the filtration tank 11 so that the porosity of the filtration part when the water to be treated is passed is 50 to 95%, preferably 60 to 90%, and more preferably 50 to 80%. Filled. The porosity is a value obtained from the following formula. And the filtration part is a region where the turbidity of the water to be treated is captured by the filter body 12, that is, the inner wall surface of the filtration tank 11 is a side surface, and both ends of the water passage direction of the filter body 12 during water flow are in the thickness direction. The part which excluded the part (part of the core material 13 in FIG. 1) which does not contribute to filtration among the layers in which the turbidity trapping part 14 of the filter body 12 is filled as both ends is said. In addition, when there is no part which does not contribute to filtration, a filtration part uses the inner wall surface of the filtration tank 11 as a side surface, and the turbidity of the filter body 12 makes the water flow direction both ends of the filter body 12 at the time of water flow the both ends of the thickness direction. Capture unit 1
4 refers to the layer filled. “The volume of the filtration part—the volume of the turbidity trapping part” is, for example, as shown in FIG. 1, the filter body 12 is not consolidated during the filtration operation (at the time of passing water to be treated) and is filled in the filtration tank 11. In the example in which the filtration part at the time of the filtration operation is formed in the state, the volume of the core material 13 is reduced from the amount of the water to be treated which overflows when the filter body 12 is put into the filtration tank 11 filled with the water to be treated. Can be easily obtained. In FIG. 1, both ends of the filter body 12 are fixed to both ends of the filtration tank 11 in the direction of water flow, and the filter body 12 spreads throughout the filter tank 11 when water to be treated is passed. A portion obtained by subtracting the core 13 from the entire inside of the tank 11 is a filtration unit.
[Formula 1]
Porosity (%) = [(volume of filtration part−volume of turbidity trapping part) / volume of filtration part] × 100

When the water to be treated is passed through such a filtration device 10, the water to be treated is each turbid trap 14 in the form of a string.
The turbidity contained in the water to be treated is trapped in the string-like turbidity capturing part 14 and the slit 15 and the turbidity is removed. The treated water is discharged from the filtration tank 11. And since the filter body 12 is filled so that the porosity of the filtration part at the time of water flow may be 50 to 95%, water flow is not prevented and a trap of turbidity is also favorable. In particular, in the present invention, since the water to be treated in which a large and strong floc is formed by the turbidity and the amphoteric electrolyte polymer is passed, the turbidity can be trapped well.

In this way, by filling the filter body 12 so that the porosity of the filtration part at the time of water flow is 50 to 95%, the water flow is not hindered and the trap of turbidity is improved. 10 can be suppressed, and for example, clear treated water having a turbidity of about 2.5 or less can be obtained. If the porosity is higher than 95%, the water flow becomes good and it becomes easy to filter at high speed, but the turbidity of the treated water becomes remarkably high, and if it is lower than 50%, the trap of turbidity is good. Although there is insufficient water flow, clogging occurs in the filtration device and the membrane separation treatment means provided in the latter stage if necessary,
The rate of differential pressure increase will be significantly higher. In particular, for example, when the filtration operation is performed at a high speed of 100 m / h or more, or the water to be treated is treated with high turbidity (for example, 20 degrees or more), the turbidity of the treated water is deteriorated or the apparatus is blocked. Although it is easy to cause the problem that it will occur, by using the filtration device 10 filled with the filter body 12 so that the porosity is 50 to 95%, Clogging can be suppressed and clear treated water can be obtained.
Of course, even when processing at low speed or processing water to be treated with low turbidity, blockage can be suppressed and clear treated water can be obtained. In addition, since it is preferable that the porosity is uniform, it is preferable that the turbidity trapping part 14 is filled up to the vicinity of both ends of the water passage direction of the filtration tank 11,
It is preferable that the turbid trap 14 is filled to the vicinity of the inner wall surface of the filtration tank 11. Also,
The volume of the filtration part is preferably not changed in volume at the time of passing water to be treated and in other states such as backwashing or when filtration is stopped, and the volume fluctuation rate of the filtration part is 30% or less, Preferably 1
It is preferably 0% or less. By setting it as such a range, a filtration apparatus can be made compact.

And in the filtration apparatus of FIG. 1, if the magnitude | size of the filtration tank 11 is a cylinder shape, it can be 100-1000 mm in diameter and 200-1000 mm in height. When the size of the filter tank 11 is larger than that of the filter body 12, the filter tank 11 is filled with a plurality of filter bodies 12, the turbidity trapping portion 14 of the filter body 12 is enlarged, and the like. The porosity of the filtration part when water is 5
It may be 0 to 95%.

Moreover, as a material of the core material 13 and the suspended matter capture | acquisition part 14, synthetic resins, such as a polypropylene, polyester, nylon, are mentioned. Here, the core material 13 may have strength by knitting synthetic fibers such as polypropylene, polyester, and nylon in the manufacturing process. Further, a wire made of a metal coated with SUS or resin that is not corroded like a torsion brush is made of a core material 13.
After the turbidity traps 14 are evenly arranged, the filter body 12 is spread radially by twisting the metal.
It is good. By improving the strength of the core member 13 in this manner, the core member 13 is not bent, and the end of the filter body 12 can be easily fixed, so that the replacement work of the filter body 12 is facilitated.

Although there is no limitation in particular in the magnitude | size of the core material 13 or the turbidity capture | acquisition part 14, For example, thickness 0.05-2m
m, width 1-50 mm, length (distance from the core when the water to be treated is passed) 10-500 mm
The thickness is preferably about 0.3 to 2 mm, the width is about 1 to 20 mm, and the length is about 50 to 200 mm.

In addition, although it was set as the cylindrical filtration tank 11 in FIG. 1, it does not need to be cylindrical and the shape which can let water flow,
That is, it may be hollow, and for example, it may have a shape in which a hollow is provided in a prism. Moreover, in the example mentioned above, although the both ends of the core material 13 were fixed to the plate 16, it is not limited to this, For example, you may make it fix only one end of a core material.

In FIG. 1, the loop-like turbidity capturing portion 14 is provided to protrude from the core material 13, but the present invention is not limited to this. For example, as shown in FIG. One end of each turbidity trapping part may be fixed to the core material. Moreover, in FIG. 1, although the cross-sectional shape of the turbidity capture | acquisition part 14 was made into square, there is no limitation in particular, For example, circular shape may be sufficient. In addition, the length of each turbidity trapping part may be the same or different. Furthermore, in the example mentioned above, the material of the turbid trap 14 is one type, but it may be two or more types. Moreover, the slit provided in the turbidity trapping part is
It may be plural or singular and may not be provided. And although the core material 13 may not be provided and it may be the filter body 12 comprised only by a turbidity capture | acquisition part, since it is preferable that the filter body 12 exists in the filtration tank 11 substantially, it is turbidity. It is preferable to fix the capturing part at a predetermined position of the filtration tank.

Such a coagulation treatment and filtration treatment can provide clear treated water. However, a membrane separation treatment using a reverse osmosis membrane (RO membrane) or a deionization treatment such as an ion exchange treatment is further provided after the filtration treatment. You may do it. Thereby, pure water or ultrapure water can be obtained. Moreover, you may further perform the refinement | purification processes of to-be-processed water, such as a decarboxylation process and activated carbon treatment.

Moreover, you may perform the solid-liquid separation process which removes the flock (aggregate) by an amphoteric electrolyte polymer from to-be-processed water by a precipitation process or a pressure levitation process before a filtration process. Precipitation treatment and pressurized flotation treatment are carried out by adjusting pH with caustic soda, slaked lime or sulfuric acid when adding amphoteric electrolyte polymer or inorganic flocculant to the water to be treated, and finally suspending with organic polymer flocculant To flock. Moreover, an organic coagulant can also be used together as needed. There is no particular limitation on the organic coagulant, such as polyethyleneimine, ethylenediamine epichlorohydrin polycondensate,
Examples include cationic organic polymers that are usually used in water treatment, such as polyalkylene polyamines, diallyldimethylammonium chloride, and polymers having quaternary ammonium salts of dimethylaminoethyl (meth) acrylate as constituent monomers. Moreover, there is no limitation in particular also in the addition amount of an organic coagulant | flocculant, What is necessary is just to adjust according to the property of to-be-processed water, However It is 0.01-10 mg / L in solid content with respect to to-be-processed water.

Moreover, you may add a coagulant | flocculant, a disinfectant, a deodorant, an antifoamer, an anticorrosive, etc. as needed. Furthermore, you may use ultraviolet irradiation, ozone treatment, biological treatment, etc. together as needed.

Here, an example of the water treatment apparatus using the water treatment method of the present invention is shown in the schematic system diagram of FIG. As shown in FIG. 4, the water treatment apparatus 30 introduces the inorganic flocculant into the reaction tank 31 from the reaction tank 31 into which the water to be treated (raw water) is introduced and the inorganic flocculant tank 32 in which the inorganic flocculant is held. And an inorganic flocculant introduction means 33 comprising a pump and the like, and a chemical introduction means 35 comprising a pump and the like for introducing the chemical from the chemical tank 34 holding the flocculant containing the predetermined amphoteric electrolyte polymer into the reaction tank 31.
1 and the water to be treated that has been subjected to agglomeration treatment such as adsorption and condensation in the reaction tank 31 is introduced.
It comprises.

In such a water treatment device 30, first, water to be treated (raw water) is introduced into the reaction tank 31. Then, the inorganic flocculant held in the inorganic flocculant tank 32 and the flocculant containing the amphoteric electrolyte polymer held in the chemical tank 34 are introduced into the reaction tank 31 by the inorganic flocculant introduction means 33 and the chemical introduction means 35. And added to the water to be treated. And the to-be-processed water to which the coagulant | flocculant and inorganic coagulant containing an amphoteric electrolyte polymer were added is stirred by the stirrer 36, and is coagulated. Next, the water to be treated that has been subjected to agglomeration treatment is discharged from the reaction tank 31 and sent to the filtration device 10.
Flock is captured and turbidity is removed. In the water treatment apparatus 30 of the present invention, since a predetermined amphoteric electrolyte polymer is used, the water to be treated discharged from the reaction vessel 31 is a flocculate and amphoteric electrolyte polymer in which a large and strong floc is formed. It is. And since this floc is capture | acquired favorably with the filtration apparatus 10, the treated water discharged | emitted from the filtration apparatus 10 is very clear. Furthermore, in the water treatment apparatus 30 of FIG. 4, since the filtration apparatus 10 filled with the filter body so as to have the predetermined porosity is used, blockage of the filtration apparatus 10 can be suppressed, and clear treated water can be obtained. The effect is obtained.

In addition, as shown in FIG. 5, a reverse osmosis membrane (R
A water treatment device 40 provided with membrane separation treatment means 41 such as an O membrane) may be used. In FIG. 5, the filtration device 10 and the membrane separation processing means 41 are arranged side by side. However, the present invention is not limited to this, and the filtration device 10 and the membrane separation processing means 41 may be integrally stacked vertically. . Thereby, the installation area can be reduced and the number of components can be reduced.

Hereinafter, although it further explains in full detail based on an Example and a comparative example, the present invention is not limited at all by this example.

(Polymer synthesis)
Methyl chloride 4 of dimethylaminoethyl methacrylate as the cationic monomer
Quaternary product (DAM) and dimethylaminoethyl acrylate methyl chloride quaternary product (
DAA), acrylamide (AAm) as the nonionic monomer, acrylic acid as the anionic monomer, a polymerization initiator (V-50 manufactured by Wako Pure Chemical Industries, Ltd., 0.001 to 0.01 for each monomer) Mol%), a monomer concentration of 10 to 35% by mass, a starting temperature of 40 ° C., aqueous solution polymerization in a nitrogen gas atmosphere, copolymerization, and polymer P- having monomer units in the ratios shown in Table 1 1 to P-4 and P-11 to P-14, P-1
6-P-17 was synthesized. The intrinsic viscosity measured at 1N-NaCl and 30 ° C. is shown in Table 1.

Example 1
Industrial water containing humic substances and biological metabolites (turbidity 35 degrees, T
Polyaluminum chloride (PAC: 10% by weight as Al ₂ O ₃ ) in 10 beakers each containing 1000 mL of OC (total organic carbon) 25 mg / L, water temperature: 18 ° C. After adding and adjusting the pH to 6.5 with 5% NaOH aqueous solution, 170 rp
m for 1 minute. Subsequently, a 0.1% aqueous solution of P-1 as an amphoteric electrolyte polymer was added to the water to be treated so as to be 0.5, 1, 2, 4 mg / L as an amphoteric electrolyte polymer, and 5 at 170 rpm. For 10 minutes at 50 rpm.

Next, the water to be treated was slowly stirred with a spatula so as not to precipitate flocs (aggregates), and was opened on a stainless steel sieve having an opening of 500 μm, an inner diameter of 75 mm, and a depth of 20 mm, and the turbidity of the permeate was measured. The turbidity was determined by a transmitted light measurement method using a kaolin standard solution. The results are shown in Table 2.

(Examples 2 to 4)
A test was performed under the same conditions and operation as in Example 1 except that the amphoteric electrolyte polymer shown in Table 2 was used instead of P-1. The results are shown in Table 2.

(Example 5)
Add ampholyte polymer P-1 and add 10 minutes at 170 rpm for 5 minutes at 170 rpm.
After stirring for a minute, water is passed from above to the filtration device 10 shown in FIG.
The test was performed under the same conditions and operation as in Example 1 except that the turbidity of the permeate was measured. The results are shown in Table 2. As shown in FIG. 1, the filtration device 10 has a filter body composed of a core material and a string-like turbid trapping part, and the filtration tank 11 is an acrylic cylindrical column having a diameter of 200 mm and a height of 500 mm, The core material 13 has a volume of 250 mL, the thickness of each turbid trap 14 is 0.5 mm, and the width is 2 mm.
, Knitted in a loop shape so that the length (distance from the core material when the water to be treated is passed) is 100 mm, and the filtration part (the core material 13 from the volume inside the filtration tank 11 when passing water) The porosity of 60) was 60%. Then, both ends of the core member 13 of the filter body 12 are fixed by plates 16 arranged above and below.

(Example 6)
The test was performed under the same conditions and operation as in Example 5 except that P-4 was used instead of P-1. The results are shown in Table 2.

(Comparative Example 1)
The same operation as in Example 1 was performed except that only PAC was added without using P-1. The results are shown in Table 3.

(Comparative Examples 2 to 8)
A test was performed under the same conditions and operation as in Example 1 except that the amphoteric electrolyte polymer shown in Table 3 was used instead of P-1. The results are shown in Table 3.

(Comparative Examples 9 to 10)
A test was conducted under the same conditions and operation as in Example 5 except that the polymer shown in Table 1 was used instead of P-1. The results are shown in Table 3.

As a result, in Examples 1 to 6 in which the ampholyte polymer having 20 to 80 mol% of the cationic monomer unit, 5 to 40 mol% of the anionic monomer unit, and 0 to 75% of the nonionic monomer unit was added, aggregation was performed. Compared with Comparative Examples 1 to 10 in the treatment, a large and strong floc is formed, and the turbidity of the treated water that has passed through the filtration device and sieve is Comparative Examples 1 to 10.
Was significantly lower than

The reference example which shows the effect of the filtration apparatus 10 below is shown.
(Relationship between porosity of filtration device, differential pressure increase and treated water turbidity)
As the water to be treated (raw water), industrial water with a turbidity of 20 degrees is used as an LV20 by using the apparatus shown in FIG.
Treated at 0 m / h for 1 week. In addition, the filter body used for the filtration apparatus is a core material 1 as shown in FIG.
3 and the string-like turbidity trapping part 14, and both ends are fixed to the plates 16 at both ends of the filtration tank 11 in the water passage direction. The core material 13 has a volume of 250 mL, and the thickness of each turbid trap 14 is 0.5 mm, the width is 2 mm, and the length (distance from the core material when the water to be treated is passed) is 100.
It is knitted into a core material in a loop shape so as to be mm, and the knitting density of the turbidity trapping part 14 is changed, and the filtration part at the time of passing water (the volume of the core material 13 from the volume inside the filtration tank 11) Minus
Filter bodies having a porosity of 30, 40, 50, 60, 70, 80, 90, 95, and 98% were prepared, and each filter body was treated with water. In addition, since the core material was fixed at both ends, the volume change rate of the filtration part was approximately 0% when the treated water was passed and at other times. The size of the filtration tank 11 is 200 mm in diameter and 500 mm in height. Further, as the flocculant, 30 mg / L polyaluminum chloride (PAC: 10 wt% as Al ₂ O ₃ ) with respect to the water to be treated and 0.7 mg / L amphoteric polymer flocculant with respect to the water to be treated. Clivest E851 (manufactured by Kurita Kogyo) was added. Table 4 shows the results of measuring the turbidity of the treated water discharged from the filtration device (treated water turbidity) and the differential pressure increase rate (differential pressure increase rate) of the filtration device. The turbidity of the treated water was determined by a transmitted light measurement method using a kaolin standard solution, and the differential pressure increase rate of the filtration device was determined by the pressure difference between the inlet and the outlet.

As a result, in the filtration device filled so that the porosity of the filtration part when passing through the filter body is 50 to 95%, the differential pressure increase rate and treatment are remarkably compared with those outside the range of 50 to 95%. It was found that water turbidity is low, clear treated water is obtained, and blockage can be suppressed.

(Reference Example 1)
As treated water (raw water), turbidity 3.4-22 degrees, TOC (total organic carbon) 0.3-4.8
mg / L, water temperature: 24.5 to 26.0 ° C. industrial water shown in FIG. 5 (raw water supply amount:
50 L / h), specifically, the reaction tank 31 for performing the aggregation treatment in order from the upstream side, the filtration device 10
Using a water treatment device 40 provided with membrane separation treatment means 41, treatment was performed at LV 200 m / h while periodically changing the water quality. As a separation membrane of the membrane separation processing means 41, M
An F membrane was used. Table 5 shows the results of measuring the turbidity of the treated water discharged from the filtration device and the differential pressure increase rate of the filtration device. As shown in FIG. 1, the filtration device 10 has a filter body 12 composed of a core material 13 and a string-like turbid trapping part, and each turbid trapping part 14 has a thickness of 0.5 mm, a width of 2 mm, and a long length. The porosity of the filtration part (filtration tank 11) during water passage is 85% at a length of 100 mm. Only one end of the core member 13 of the filter body 12 is fixed to the upstream plate 16 in the water flow direction. Note that one end of the core member 13 is not fixed, but one end is fixed to the upstream plate 16, so that the filter body 12 spread substantially uniformly throughout the entire filtration tank when the treated water was passed. Further, polyaluminum chloride (PAC: 10% by weight as Al ₂ O ₃ ) was added as a flocculant so as to be 30 mg / L with respect to the water to be treated.

(Reference Example 2)
The same operation as in Reference Example 1 was performed except that 2 to 5 slits were inserted in addition to the portion fixed to the core material of each turbid trapping part in the loop shape.

(Reference Example 3)
The same operation as in Reference Example 2 was performed except that both ends of the core member 13 of the filter body 12 were fixed to the upstream and downstream plates 16 in the water flow direction, respectively.

As shown in Table 5, in Reference Examples 1 to 3, it was found that the treated water turbidity and the differential pressure increase rate were low, clear treated water was obtained, and no clogging of the filtration device occurred. Further, in Reference Example 2 in which the filter body was provided with slits, the treated water turbidity decreased and the differential pressure increase rate was slower than in Reference Example 1. And in the reference example 3 which fixed the both ends of the filter body to the filtration tank, the to-be-processed water turbidity at the time of high turbidity fell rather than the reference example 2.

DESCRIPTION OF SYMBOLS 10 Filtration apparatus, 11 Filtration tank, 12 Filter body, 13 Core material, 14 Suspension trapping part, 16 Plate, 30, 40 Water treatment apparatus

Claims (4)

Cationic monomer units 20 to 80 mol% and anionic monomer units 5 to 4
A flocculant containing an amphoteric electrolyte polymer having 0 mol% and nonionic monomer units of 0 to 75% is added to the water to be treated, and the water to be treated is subjected to agglomeration treatment. A water treatment method characterized by passing water through a filtration means having a fibrous filter for capturing turbidity in the water to be treated. In the filtration means, the filter body having a string-like turbidity trapping section has a porosity of 5 at the time of passing water.
The water treatment method according to claim 1, wherein the filtration tank is filled so as to be 0 to 95%. The water treatment method according to claim 1 or 2, wherein an inorganic flocculant is added to the water to be treated before the filtration treatment. A reaction tank into which treated water is introduced;
Cationic monomer units 20-80 mol% and anionic monomer units 5-40
The flocculant introduction which introduces the flocculant containing the amphoteric electrolyte polymer which has mol% and nonionic monomer units 0-75% in the front | former stage of the said reaction tank or reaction tank, and adds the said flocculant to to-be-processed water Means,
A filtration treatment means provided at a subsequent stage of the reaction tank and filtering the treated water coagulated in the reaction tank, and having a fibrous filter for capturing turbidity in the treated water to be passed therethrough. And a water treatment apparatus.

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