JP5218731B2 - Water treatment method and water treatment apparatus - Google Patents

Description

  The present invention relates to a water treatment method and a water treatment apparatus for industrial water, river water or lake water containing humic substances and the like.

  As a method for treating the water to be treated consisting of industrial water, river water or lake water, an inorganic flocculant such as aluminum salt or iron salt is added, and suspended substances, colloidal components, organics contained in the water to be treated are added. A method is known in which a substance is aggregated and coarsened, and then a solid-liquid separation process such as a membrane separation process, a precipitation process, a pressurized flotation process, and a filtration is performed (Patent Document 1, etc.).

  However, in the method of adding an inorganic flocculant, the aggregation of soluble organic substances such as humic substances, fulvic acid organic substances, biological metabolites such as sugars produced by algae, synthetic chemical substances such as surfactants, etc. is incomplete. There is a problem of becoming. In particular, when a membrane separation process is performed as a solid-liquid separation process, there is a problem in that the soluble organic matter contaminates the membrane and lowers the membrane filtration flow rate. And in order to make aggregation of such a soluble organic substance sufficient, when a large amount of inorganic flocculants is added, the amount of sludge will increase. In addition, when a membrane treatment is performed as a solid-liquid separation treatment, a new problem arises that the membrane is contaminated by an inorganic flocculant and causes an increase in differential pressure. Therefore, there is a need for a water treatment method that can remove soluble organic substances in water to be treated comprising industrial water, river water, or lake water without adding a large amount of an inorganic flocculant.

  In addition, there is a demand for efficient water aggregation and water treatment. For example, Patent Document 1 discloses a technique for measuring the absorbance of water to be treated and controlling the amount of inorganic flocculant added based on the measurement result. It is disclosed. However, the method of Patent Document 1 has a problem that the removal of soluble organic substances is insufficient as described above.

JP 2006-272111 A

  In view of the circumstances described above, the present invention provides a water treatment method and a water treatment apparatus capable of efficiently removing soluble organic substances from water to be treated comprising industrial water, river water, or lake water without adding a large amount of an inorganic flocculant. The purpose is to provide.

  As a result of diligent studies to achieve the above object, the present inventors have swelled in an amount of water corresponding to the absorbance of water to be treated consisting of industrial water, river water or lake water, and are cationic polymers that do not substantially dissolve in water. It was found that the above-mentioned object was achieved by adding particles made of to the water to be treated, and the present invention was completed.

  That is, the water treatment method of the present invention adds a particle made of a cationic polymer that swells in water and does not substantially dissolve in water to water to be treated consisting of industrial water, river water, or lake water, and then adsorbs it. A water treatment method for performing liquid separation treatment, wherein the amount of the particles added to the water to be treated is controlled based on the measurement result of the absorbance of the water to be treated before the adsorption treatment.

  In the water treatment method of the present invention, the absorbance is preferably a value obtained by measuring an ultraviolet part of 200 to 400 nm and a visible part of 500 to 700 nm at one wavelength or more.

  The solid-liquid separation process is preferably a membrane separation process using a separation membrane.

  Further, the water to be treated may be humic-containing water.

  Moreover, it is preferable to add an inorganic flocculant to the water to be treated during the adsorption treatment.

  Other aspects of the present invention are a reaction tank, treated water introduction means for introducing treated water comprising industrial water, river water, or lake water into the reaction tank, and a cation that swells in water and does not substantially dissolve in water. A polymer particle introducing means for introducing particles made of a functional polymer in the previous stage of the reaction tank or the reaction tank and adding the particles to the water to be treated; and a discharging means for discharging the water to be treated adsorbed in the reaction tank; A solid-liquid separation treatment means for subjecting the treated water discharged from the discharge means to a solid-liquid separation treatment; an absorbance measurement means for measuring the absorbance of the treated water in the preceding stage of the polymer particle introduction means; and the absorbance measurement means. An addition amount control means for controlling the addition amount of the particles to the water to be treated based on the measured absorbance.

  By adding cationic polymer particles that swell in water and do not substantially dissolve in water to water to be treated consisting of industrial water, river water, or lake water, soluble organic substances can be adsorbed on the particles. And since this particle | grain is insoluble in water, a soluble organic substance with a particle | grain can be easily separated and removed from to-be-processed water by carrying out solid-liquid separation of the aggregate which the soluble organic substance adsorb | sucked to the particle | grain. And since the addition amount of this particle | grain measures the light absorbency of to-be-processed water which is to-be-processed water, and is controlled according to the light absorbency, a soluble organic substance can be efficiently removed from to-be-processed water. Therefore, according to the present invention, soluble organic substances can be efficiently removed from the water to be treated without adding a large amount of inorganic flocculant, and the amount of sludge and membrane contamination can be suppressed.

Hereinafter, the present invention will be described in detail based on embodiments.
The water treatment method of the present invention is a solid-liquid separation after adding particles made of a cationic polymer that swells in water and does not substantially dissolve in water to water to be treated consisting of industrial water, river water, or lake water, and then performs adsorption treatment. A water treatment method for treating, based on the result of measuring the absorbance of the water to be treated before the adsorption treatment, the amount of particles made of a cationic polymer that swells in water and does not substantially dissolve in water. Control.

  As industrial water, river water or lake water that is treated water, for example, humic substances, fulvic acid organic substances, biological metabolites such as sugar produced by algae, or synthetic chemical substances such as surfactants, etc. Including. The water treatment method of the present invention is particularly suitable for water containing biological metabolites such as sugar produced by humic substances, algae and the like. 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. It has a soluble COD component, suspended matter and chromaticity component.

  Cationic polymers that swell in water that constitutes the particles to be added to the water to be treated and do not substantially dissolve in water include, for example, primary amines, secondary amines, tertiary amines and their acid salts, quaternary ammonium groups, and the like. It is a copolymer of a cationic monomer having a functional group and a cross-linking agent monomer for substantially not dissolving in water. 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. Examples of the cross-linking agent monomer include divinyl monomers such as methylene bisacrylamide. Moreover, it is good also as a copolymer with the anionic or nonionic monomer copolymerizable with the said cationic monomer. Specific examples of the anionic monomer to be copolymerized include (meth) acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and alkali metal salts thereof. It is necessary to use a small amount so as not to impair the properties as a conductive polymer. Nonionic monomers include (meth) acrylamide, N isopropylacrylamide, N methyl (NN dimethyl) acrylamide, acrylonitrile, styrene, methyl or ethyl (meth) acrylate. Each monomer may be one kind or plural kinds. The amount of the crosslinking agent monomer such as divinyl monomer is required to be 0.0001 to 0.1 mol% based on the total monomer, and this amount is composed of a cationic polymer that swells in water and does not substantially dissolve in water. The degree of particle swelling and the particle size in water can be adjusted. And as the particle | grains which consist of a cationic polymer which swells in water and does not melt | dissolve in water substantially, for example, Akogel C (made by Mitsui Cytec Co., Ltd.) is marketed. Alternatively, an anion exchange resin such as WA20 (manufactured by Mitsubishi Chemical Corporation) may be used as a cationic polymer that swells in water and does not substantially dissolve in water. Further, the average particle size of the particles made of a cationic polymer that swells in water and does not substantially dissolve in water is not particularly limited, but the average particle size in a reversed-phase emulsion liquid or a suspension-like dispersion liquid, that is, in water The average particle size in the unswelled state is preferably 100 μm or less, more preferably 0.1 to 10 μm. This is because the smaller the particle, the higher the effect of adsorbing soluble organic substances such as humic substances contained in the water to be treated, but if it is too small, solid-liquid separation becomes difficult.

  By adding cationic polymer particles that swell in water and do not substantially dissolve in water to the water to be treated, soluble organic substances can be adsorbed on the particles, and the particles are insoluble in water. Therefore, by performing solid-liquid separation of the aggregate in which the soluble organic substance is adsorbed on the particles, the soluble organic substance can be easily separated and removed from the water to be treated together with the particles. Therefore, soluble organic substances can be removed from the water to be treated without adding a large amount of inorganic flocculant.

  There is no particular limitation on the form of adding particles composed of a cationic polymer that swells in water and does not substantially dissolve in water to the water to be treated. For example, the particles may be used as they are, or dispersed in water, You may add in the form of an emulsion liquid or a suspension-like dispersion liquid. In any case, the water to be treated is adsorbed by adding particles made of a cationic polymer that swells in water and does not substantially dissolve in water, that is, the water to be treated swells in water. However, it is only necessary to contact the particles made of a cationic polymer that is substantially insoluble in water so that soluble organic substances such as humic substances and biological metabolites contained in the water to be treated are adsorbed to the particles.

  Moreover, you may add the particle | grains which consist of a cationic polymer which swells in 2 or more types of water, and does not melt | dissolve in water substantially to treated water. Since the cationic polymer constituting the above particles swells in water and does not substantially dissolve in water, particles made of a cationic polymer that swells in water and does not substantially dissolve in water are also classified as ordinary polymer flocculants. Unlike, it swells in water and does not substantially dissolve in water. “Substantially insoluble in water” means that the degree of water solubility is such that it can exist as particles composed of a cationic polymer in water. Specifically, for example, solubility in water at 30 ° C. Is about 0.1 g / L or less. The degree of swelling of these particles in water is about 10 to 200 times the particle size in water with respect to the particle size when not swollen with water.

  Here, although it demonstrates in detail below about the particle | grains which consist of a cationic polymer made into the form of a reverse phase emulsion liquid, it is not limited to this form. In addition, it is not a special thing but is a very general reverse phase (W / O) emulsion polymer.

  The inverse emulsion liquid contains the cationic polymer, water, a hydrocarbon liquid, and a surfactant. And mass ratio (%) of each component is cationic polymer: water: hydrocarbon liquid: surfactant = 20-40: 20-40: 20-40: 2-20, and the cationic polymer and water. The total mass is preferably 40 to 60% by mass with respect to the total mass of the cationic polymer, water, hydrocarbon liquid and surfactant.

  Examples of the hydrocarbon liquid include, but are not limited to, isoparaffins such as isohexane, and aliphatic hydrocarbon liquids such as n-hexane, kerosene, and mineral oil.

  Examples of the surfactant include polyoxyethylene ethers of higher aliphatic alcohols having 10 to 20 carbon atoms, or higher fatty acids having 10 to 22 carbon atoms, such as HLB (hydrophilic lipophilic balance) of 7 to 10. A polyoxyethylene ester is mentioned. Examples of the former include polyoxyethylene (EO addition mole number = 3 to 10) ethers such as lauryl alcohol, cetyl alcohol, stearyl alcohol, and oleyl alcohol. Examples of the latter include polyoxyethylene (EO addition mole number = 3 to 10) esters such as lauric acid, palmitic acid, stearic acid, and oleic acid.

  The reverse phase emulsion liquid is obtained by polymerizing a monomer (emulsion polymerization or suspension polymerization) by mixing a cationic monomer or a crosslinking agent monomer, which is a raw material of the cationic polymer, with water, a hydrocarbon liquid, and a surfactant. However, the present invention is not limited to this. For example, after various monomers are solution polymerized, they are pulverized with a homogenizer, and then added to a hydrocarbon liquid together with a dispersant such as a surfactant. It is done.

  When particles made of a cationic polymer that swells in water and does not substantially dissolve in water are added to the water to be treated, the surface area of the particles is preferably large. Therefore, it is preferable to add the particles in the form of the above-mentioned reversed phase emulsion liquid or suspension-like dispersion liquid to the water to be treated after adding the particles to the water under stirring to swell the particles.

  There is no particular limitation on the amount of particles composed of a cationic polymer that swells in water and does not substantially dissolve in water, but it is 1 to 50% by mass with respect to membrane contaminants contained in the water to be treated. It is preferable to set the degree.

  And in this invention, the addition amount of the particle | grains which consist of a cationic polymer which swells in water and does not melt | dissolve substantially in water is controlled according to the light absorbency of industrial water, river water, or lake water which is to-be-processed water. Specifically, the absorbance of the water to be treated is measured before the adsorption treatment, and the amount of particles made of a cationic polymer that swells in water and does not substantially dissolve in water is controlled based on the measurement result. More specifically, first, the absorbance of the water to be treated and the amount of particles made of a cationic polymer that swells in water suitable for treating the water to be treated and does not substantially dissolve in water. The relationship between the addition amount sufficient to agglomerate the soluble organic substance and not excessive is obtained as addition amount control information. Then, when water treatment is performed, the absorbance of the water to be treated is measured, and the addition amount of the particles is controlled based on the measurement result of the absorbance and the addition amount correction information.

  Here, with respect to the water to be treated, there is a correlation represented by the following formula between the absorbance obtained by measuring one or more wavelengths of the ultraviolet part having a wavelength of 200 nm to 400 nm and the visible part having a wavelength of 500 nm to 700 nm and the concentration of the soluble organic substance.

    Dissolved organic matter concentration = A × [UV absorbance-visible absorbance]

  And between the concentration of soluble organic matter and the optimum addition amount of particles determined from the time required to filter a certain amount of sample water using a 0.45 μm membrane filter (hereinafter referred to as “KMF value”). Are correlated. Therefore, by measuring the ultraviolet absorbance and the visible absorbance at one wavelength or more, the optimum addition amount of particles made of a cationic polymer that swells in water and does not substantially dissolve in water can be estimated.

  Specifically, a jar test is performed in advance on water to be treated having different water qualities, for example, water to be treated such as industrial water collected on different days, and ultraviolet absorbance and visible absorbance in the following formula (I) are obtained. And the relational expression (addition amount control information) between the difference between and the optimum addition concentration of particles. In the formula (I), A to C are constants depending on the water quality such as the concentration of soluble organic matter in the water to be treated, E260 represents the absorbance at a wavelength of 260 nm, and E660 represents the absorbance at a wavelength of 660 nm. Then, when water treatment is performed, the absorbance of the water to be treated is measured, the optimum addition concentration of the particles is obtained from the measurement result of the absorbance and the following formula (I), and the particles of the optimum addition amount are added to the water to be treated.

Addition concentration of particles made of cationic polymer which swells in water and does not substantially dissolve in water = A × (E260−E660) ^B + C (I)

In the above-described example, the relational expression between the difference between the ultraviolet absorbance and the visible absorbance and the optimum added concentration of the particles is shown as the addition amount control information. However, the present invention is not limited to this. It is good also as control. As the threshold control, when the absorbance difference is less than the predetermined value a ₁ , the particle addition concentration is b _1, and when the absorbance difference is the predetermined value a _{1 to} a ₂ , the particle addition concentration is b ₂ and the absorbance difference is the predetermined value. When it exceeds a ₂ , for example, the additive concentration of the particles is b ₃ , but it is not limited thereto.

  Thus, based on the amount of soluble organic matter contained in the water to be treated, by controlling the amount of particles made of a cationic polymer that swells in water and does not substantially dissolve in water, Since particles composed of a cationic polymer that swells and does not substantially dissolve in water can be added to the water to be treated, the water to be treated can be treated efficiently. In addition, even when the quality of the water to be treated varies, the optimum amount of particles made of a cationic polymer that swells in water and does not substantially dissolve in water according to the quality of the treated water after variation, Treated water with high clarity can be obtained stably.

  Further, an inorganic flocculant may be added to the water to be treated during the adsorption treatment. By adding an inorganic flocculant as the flocculant of the soluble organic substance, the soluble organic substance is agglomerated and the effect of removing the soluble organic substance is increased. The inorganic flocculant may be added before the solid-liquid separation treatment, and may be before or after adding particles made of a cationic polymer that swells in water and does not substantially dissolve in water, Moreover, you may add simultaneously with the particle | grains which consist of a cationic polymer which swells in water and does not melt | dissolve in water substantially. The inorganic flocculant is not particularly limited, and examples thereof include an aluminum salt such as a sulfuric acid band and polyaluminum chloride, and an iron salt such as ferric chloride and ferrous sulfate.

  The amount of the inorganic flocculant added is not particularly limited, and may be adjusted according to the properties of the water to be treated, and is generally 0.5 to 10 mg / L in terms of aluminum or iron with respect to the water to be treated. It is preferable to control based on the measurement result of the absorbance of the water to be treated before the adsorption treatment, similarly to the addition amount of the particles made of a cationic polymer that swells in water and does not substantially dissolve in water.

  Specifically, by performing a jar test in advance on water to be treated having different water quality, for example, water to be treated collected on different days, ultraviolet absorbance as shown in the following formulas (II) and (III) And a relational expression (addition amount control information) between the difference between the absorbance of the visible region and the optimum absorbance of the particles and the inorganic flocculant. In the formulas (II) and (III), D to I are constants depending on the water quality such as the concentration of soluble organic matter in the water to be treated. Then, when the water treatment is performed, the absorbance of the water to be treated is measured, and the optimum addition concentration of the particles and the inorganic flocculant is obtained from the absorbance and the following (II) and (III). Add to treated water.

Concentration of particles composed of a cationic polymer which swells in water and does not substantially dissolve in water = D × (E260−E660) ^E + F (II)
Inorganic flocculant addition concentration = G × (E260−E660) ^H + I (III)

  Furthermore, the addition amount of particles made of a cationic polymer that swells in water and does not substantially dissolve in water or the addition amount of an inorganic flocculant may be varied according to the flow rate of the water to be treated.

  In addition, after the adsorption treatment, the aggregation state of the water to be treated before the solid-liquid separation treatment is measured, and depending on the aggregation state, particles or inorganic particles made of a cationic polymer that swells in water and does not substantially dissolve in water. The amount of the flocculant added may be corrected. Thereby, a very good aggregation process can be performed. In addition, as a method for measuring the aggregation state, a method using a light blocking fine particle sensor, a light scattering fine particle sensor, or the like that detects the degree of clarification between the aggregated particles (floc) of the water to be treated has been exemplified. Can do. As a method of correcting the addition amount of particles or inorganic flocculants made of a cationic polymer that swells in water according to the aggregation state and does not substantially dissolve in water, for example, when turbidity is measured as the aggregation state, the turbidity Based on the data, the addition rate correction information such as the above formulas (I) to (III) is set by setting a threshold such as K times the addition rate when the turbidity is J or more and M times when the turbidity is L or more. It is preferable to correct.

  Thus, after adding the particle | grains which consist of the cationic polymer which swells in water and does not melt | dissolve substantially in water, an to-be-processed water is subjected to solid-liquid separation processing. Examples of the solid-liquid separation treatment include membrane separation treatment, precipitation treatment, pressurized flotation treatment, and filtration.

  Examples of the membrane separation treatment include a microfiltration membrane (MF membrane), an ultrafiltration membrane (UF membrane), a nanofiltration membrane (NF membrane), or a reverse osmosis membrane (RO membrane). These membranes may be used alone or in one or more stages. For example, membrane separation treatment that combines various membranes, such as membrane separation treatment with MF membrane or UF membrane, followed by membrane separation treatment with RO membrane. It is good. Here, industrial water, river water, or lake water, which is treated water, includes humic acid and fulvic acid organic substances, biological metabolites such as sugar produced by algae, synthetic chemical substances such as surfactants, etc. Since membrane contaminants are included, there is a problem that when a membrane separation process is performed, soluble organic substances that are membrane contaminants are adsorbed on the membrane surface and membrane separation performance deteriorates. In the present invention, before the membrane separation treatment, particles made of a cationic polymer that swells in water and does not substantially dissolve in water are added, so that soluble organic substances as membrane contaminants are adsorbed and aggregated on the particles. After that, a membrane separation process is performed. Accordingly, water having a low concentration of soluble organic substances that are membrane contaminants can be subjected to membrane separation treatment, so that adsorption of membrane contaminants to the membrane can be reduced, and deterioration of membrane separation performance can be suppressed.

  In addition, the precipitation treatment and pressure levitation treatment are carried out by adjusting the pH with caustic soda, slaked lime, sulfuric acid, etc. after adding particles or inorganic flocculants made of a cationic polymer that swells in water and does not substantially dissolve in water to the treated water. Finally, the suspension is flocked with an organic polymer flocculant. Moreover, an organic coagulant can also be used together as needed. There is no particular limitation on the organic coagulant, for example, polyethyleneimine, ethylenediamine epichlorohydrin polycondensate, polyalkylene polyamine, polymers having quaternary ammonium salts of diallyldimethylammonium chloride or dimethylaminoethyl (meth) acrylate as constituent monomers, etc. Examples include cationic organic polymers that are usually used in water treatment. 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. The organic polymer flocculant is not particularly limited, and a polymer flocculant usually used in water treatment can be used. For example, poly (meth) acrylic acid, copolymers of (meth) acrylic acid and (meth) acrylamide, and anionic organic polymer flocculants such as alkali metal salts thereof, poly (meth) acrylamide, etc. Nonionic organic polymer flocculants, homopolymers composed of cationic monomers such as dimethylaminoethyl (meth) acrylate or quaternary ammonium salt thereof, dimethylaminopropyl (meth) acrylamide or quaternary ammonium salt thereof, and the like Examples thereof include cationic organic polymer flocculants such as a copolymer of a cationic monomer and a nonionic monomer copolymerizable. Moreover, there is no limitation in particular also in the addition amount of an organic type polymer flocculant, and what is necessary is just to adjust according to the property of treated water, but it is 1-20 mg / L in solid content with respect to to-be-treated water.

  Further, after the adsorption treatment, water to be treated may be further purified, such as decarbonation treatment or activated carbon treatment. Moreover, you may have further deionization processes, such as an ion exchange process. Thereby, pure water or ultrapure water can be obtained.

  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. 1, the water treatment apparatus 1 includes a raw water tank 11 for storing water to be treated (industrial water, river water, lake water), a reaction tank 12, and a reaction tank 12 for treating water from the raw water tank 11. The chemical is introduced into the reaction vessel 12 from the treated water introduction means 13 such as a pump to be introduced into the vessel and the chemical vessel 14 in which particles such as particles made of a cationic polymer that swells in water and does not substantially dissolve in water are held. A chemical introduction means 15 (polymer particle introduction means) comprising a pump and the like; an inorganic flocculant introduction means 17 comprising a pump and the like for introducing the inorganic flocculant from the inorganic flocculant tank 16 holding the inorganic flocculant into the reaction tank 12; And a discharge means 18 for discharging the water to be treated adsorbed in the reaction tank 12. Further, on the downstream side of the reaction tank 12, a membrane separation processing means (solid-liquid separation processing means) 19, a decarboxylation processing means 20, and a reverse osmosis membrane separation processing means 21 are provided in this order. Further, the raw water tank 11 is provided with an absorbance measuring means 31 for measuring the absorbance of the stored water to be treated. The absorbance data measured by the absorbance measuring means 31 is received and introduced from the chemical tank 14 into the reaction tank 12. The amount of addition of particles composed of a cationic polymer that swells in water and does not substantially dissolve in water, and the amount of addition of the inorganic flocculant introduced from the inorganic flocculant tank 16 to the reaction tank 12 are calculated and the amount added is controlled. An addition amount control means 32 is provided. In the present embodiment, the addition amount control means 32 uses particles and inorganic flocculants made of a cationic polymer that swells water to be treated with various absorbances having different water qualities in advance with a jar tester and does not substantially dissolve in water. By adding water, the formula for obtaining the relationship between the absorbance of the water to be treated and the optimum addition amount of particles made of a cationic polymer that swells in water and does not substantially dissolve in water is included as addition amount correction information. The addition amount control means 32 calculates the optimum addition amount from the absorbance data measured by the absorbance measurement means 31 and this relational expression (addition amount correction information), and the addition amount of particles introduced from the chemical introduction means 15. To control. Similarly, the addition amount control means 32 uses particles and inorganic flocculants made of a cationic polymer that swells water to be treated having various absorbances having different water qualities in advance with a jar tester and does not substantially dissolve in water. By adding water, the formula for obtaining the relationship between the absorbance of the water to be treated and the optimum addition amount of the inorganic flocculant is included as the addition amount correction information. Then, the addition amount control means 32 calculates the optimum addition amount from the absorbance data measured by the absorbance measurement means 31 and this relational expression (addition amount correction information), and inorganic aggregation introduced from the inorganic flocculant introduction means 17. The amount of agent added is controlled.

  In such a water treatment apparatus 1, the absorbance of the water to be treated stored in the raw water tank 11 is measured by the absorbance measurement means 31 and sent to the addition amount control means 32 as absorbance data. Then, the water to be treated is introduced into the reaction tank 12 by the water to be treated introducing means 13, and swells in the water held in the chemical tank 14, and is a chemical such as particles made of a cationic polymer that does not substantially dissolve in water, The inorganic flocculant held in the inorganic flocculant tank 16 is introduced into the reaction tank 12 by the chemical introduction means 15 and the inorganic flocculant introduction means 17 and added to the water to be treated. The addition amount of the particles made of the cationic polymer that swells in water and does not substantially dissolve in water and the inorganic flocculant are calculated by the addition amount control means 32 from the absorbance data measured by the absorbance measurement means 31. The addition amount control means 32 controls the chemical introduction means 15 and the inorganic flocculant introduction means 17 so that the calculated addition amount is obtained.

  Next, the water to be treated to which particles made of a cationic polymer that swells in water and does not substantially dissolve in water and the like is added is stirred by the stirrer 22 and adsorbed. Next, the water to be treated that has been subjected to the adsorption treatment is discharged from the reaction tank 12 by the discharge means 18, sent to the membrane separation treatment means 19 having an MF membrane, subjected to membrane separation treatment, and particles made of a cationic polymer after the adsorption treatment. Is removed from the treated water. In the present invention, the membrane separation treatment means 19 performs a membrane separation treatment after adsorbing a soluble organic substance that is a membrane contaminant using particles made of a cationic polymer that swells in water and does not substantially dissolve in water. It is possible to reduce the adsorption of membrane contaminants to the membrane surface and suppress the degradation of membrane separation performance.

  Next, the water to be treated that has been subjected to the membrane separation treatment is sent to the subsequent decarboxylation treatment means 20 for decarboxylation treatment. Then, it is sent to the reverse osmosis membrane separation processing means 21 having the RO membrane, and membrane separation processing by the RO membrane is performed. The treated water that passes through the reverse osmosis membrane separation treatment means 21 is obtained by adsorbing membrane contaminants using particles made of a cationic polymer that swells in water and does not substantially dissolve in water, Since the water to be treated after being subjected to membrane separation treatment by the membrane separation treatment means 19 having an MF membrane, it is very clear and remarkably suppresses the deterioration of the RO membrane that is greatly affected by membrane contaminants such as biological metabolites. be able to. If deionization treatment such as ion exchange is performed before or after the membrane separation treatment by the reverse osmosis membrane separation treatment means 21, pure water or ultrapure water can be obtained, and the membrane separation apparatus 1 can produce pure water. Equipment and ultrapure water production equipment.

  In the water treatment apparatus shown in FIG. 1, an embodiment in which particles made of a cationic polymer that swells in water and does not substantially dissolve in water, an inorganic flocculant, or the like is introduced into the reaction tank 12. You may make it add to the to-be-processed water before introduce | transducing into. Moreover, although the MF membrane is shown as the membrane separation processing means 19, a UF membrane, an RO membrane, an NF membrane, or the like may be used. Furthermore, in the water treatment apparatus 1 of FIG. 1 described above, the particles made of the cationic polymer after the adsorption treatment are removed by the membrane separation treatment means 19, but the particles are subjected to precipitation treatment or pressurized flotation treatment in the reaction vessel 12. For example, it may be removed from the water to be treated. Further, activated carbon treatment or the like may be further performed between the decarboxylation treatment means 20 and the reverse osmosis membrane separation treatment means 21.

  In addition, for example, a sensor (such as an aggregation sensor) that can measure the aggregation state in the reaction vessel 12 is installed in the reaction vessel 12 or the subsequent stage, and it swells in water according to the aggregation state measurement data and substantially becomes water. You may make it correct | amend the addition amount of the particle | grains which consist of the cationic polymer which does not melt | dissolve, and an inorganic flocculant, or when an agglomeration defect generate | occur | produces, you may make it transmit an alarm signal. The addition amount control means 32 also serves as a control means for correcting the addition amount of particles or inorganic flocculants made of a cationic polymer that swells in water and does not substantially dissolve in water according to the aggregation state measurement data. Alternatively, a separate control unit may be provided.

  EXAMPLES Hereinafter, although this invention is explained in full detail based on an Example and a comparative example, this invention is not limited at all by this Example.

Example 1
In May, when the water quality changes due to rain (2 weeks), industrial water containing humic substances and biological metabolites is passed through the water treatment device shown in FIG. The treatment was performed by adding particles made of a cationic polymer that swells in water and does not substantially dissolve in water based on the absorbance data (Acogel C, manufactured by Mitsui Cytec). E260 of industrial water in raw water tank 11 during water flow test, addition concentration of acogel C, addition concentration of inorganic flocculant (PAC), KMF value of industrial water after adsorption treatment (using a membrane filter with a diameter of 47 μm, vacuum Table 1 shows the MF membrane ΔP rise rate (MF transmembrane differential pressure rise rate), which is obtained by adding the first 500 mL filtration time and the subsequent 500 mL filtration time when filtration is performed at a suction pressure of 500 mmHg.

  In addition, the light absorbency was measured about 260 nm and 660 nm using the S :: CAN sensor (S :: CAN company make, cell width 35mm). Moreover, it adjusted with the pH adjuster so that the inside of the reaction tank 12 might be set to pH6.5. Further, the relational expression for controlling the addition amount of Akogel C by the addition amount control means 32 in accordance with the absorbance data of industrial water is obtained by performing a jar test in advance using the Akogel C on industrial water collected on different days, It calculated | required from the relationship between the difference of a light absorbency (E260) and a visible part light absorbency (E660), and the optimal addition amount of acogel C. FIG. The obtained relational expression is shown in the following expression (1).

Concentration of Akogel C (mg / L)
= 25.13 × (E260−E660) −1.334 (1)

(Example 2)
The same operation as in Example 1 was performed except that polyaluminum chloride (PAC) was added as an inorganic flocculant so as to be a constant 30 mg / L together with Akogel C. In addition, since Example 2 and Examples 3 to 4 and Comparative Examples 1 and 2 shown below use the same industrial water as Example 1, they were performed in parallel with Example 1.

(Example 3)
The same operation as in Example 2 except that particles composed of a cationic polymer that swells in water and does not substantially dissolve in water are added based on the following formula (2) and an inorganic flocculant is added based on the following formula (3). Went. In addition, Formula (2) and Formula (3) carry out a jar test beforehand using the Akogel C and PAC about the industrial water extract | collected on the different day, and an ultraviolet part absorbance (E260) and a visible part absorbance (E660) It calculated | required from the relationship between the difference and the optimal addition amount of Akogel C and PAC.

Concentration of Akogel C (mg / L)
= 20.14 × (E260−E660) −1.06 (2)
Concentration of PAC (mg / L as PAC)
= 121.79 × (E260−E660) −3.89 (3)

Example 4
In the water treatment apparatus shown in FIG. 1, a coagulation sensor (manufactured by Kurita Kogyo, manufactured by Kurita Kogyo Co., Ltd.) is further provided in the vicinity of the outlet of the reaction tank 12, and the coagulation degree of industrial water in which flocs are formed is measured by adding Akogel C and PAC. In addition to controlling the addition amount of Akogel C and PAC in addition to the control in equations (2) and (3), the turbidity between flocs (turbidity due to unaggregated microcolloids) is increased by 2 degrees or more. In this case, the same operation as in Example 3 was performed except that control was performed to increase the addition amount of Akogel C and PAC by 1.5 times.

(Comparative Example 1)
The same operation as in Example 1 was performed except that PAC was used instead of Akogel C and PAC was added based on the following formula (4).

Concentration of PAC (mg / L as PAC)
= 502.6 × (E260−E660) −32.7 (4)

(Comparative Example 2)
The same operation as in Example 1 was performed except that the amount of Akogel C added was kept constant at 4 mg / L.

As a result, in Example 1, compared with Comparative Example 1 and Comparative Example 2, the MF membrane ΔP ascent rate and KMF value were low, and water with good membrane filtration was obtained. Moreover, in the comparative example 1, the usage-amount of PAC increased and generation | occurrence | production of sludge increased. In Comparative Example 2, since the addition amount was not controlled, the KFM value sometimes increased.
In Example 2, it was confirmed that the membrane filterability was better than that in Example 1, and the membrane filterability was improved by using PAC together. Moreover, in Example 3, since the addition amount of both Akogel and PAC was controlled, the membrane filterability was further improved as compared with Example 2. And in Example 4 which further controlled the addition amount of an akogel and PAC according to the aggregation state, the membrane filterability rose further compared with Examples 1-3.

1 is a schematic system diagram of a water treatment device according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water treatment apparatus 11 Raw water tank 12 Reaction tank 13 To-be-processed water introduction means 14 Chemical tank 15 Chemical introduction means 16 Inorganic flocculant tank 17 Inorganic flocculant introduction means 18 Discharge means 19 Membrane separation processing means 20 Decarbonation treatment means 21 Reverse osmosis treatment means 21 Membrane separation processing means 22 Stirrer 31 Absorbance measurement means 32 Addition amount control means

Claims (6)

  A water treatment method for solid-liquid separation after adding particles made of a cationic polymer that swells in water and does not substantially dissolve in water to water to be treated consisting of industrial water, river water, or lake water, followed by adsorption treatment The water treatment method is characterized in that the amount of the particles added to the water to be treated is controlled based on the measurement result of the absorbance of the water to be treated before the adsorption treatment.   2. The water treatment method according to claim 1, wherein the absorbance is a value obtained by measuring an ultraviolet part of 200 to 400 nm and a visible part of 500 to 700 nm at one wavelength or more.   The water treatment method according to claim 1 or 2, wherein the solid-liquid separation treatment is a membrane separation treatment using a separation membrane.   The water treatment method according to any one of claims 1 to 3, wherein the water to be treated is humic-containing water.   The water treatment method according to any one of claims 1 to 4, wherein an inorganic flocculant is added to the water to be treated during the adsorption treatment.   A reaction tank, treated water introduction means for introducing treated water consisting of industrial water, river water, or lake water into the reaction tank, and particles made of a cationic polymer that swells in water and does not substantially dissolve in water. Polymer particle introduction means for introducing the particles into the water to be treated after being introduced in the preceding stage of the tank or the reaction tank, discharge means for discharging the water to be treated that has been subjected to adsorption treatment in the reaction tank, and the waste discharged from the discharge means Solid-liquid separation treatment means for subjecting treated water to solid-liquid separation, Absorbance measurement means for measuring the absorbance of the water to be treated in the previous stage of the polymer particle introduction means, and the absorbance based on the absorbance measured by the absorbance measurement means A water treatment apparatus comprising: an addition amount control means for controlling the amount of particles added to the water to be treated.

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