JP6083949B2 - Sustained release flocculant, turbid water treatment method and method for producing sustained release flocculant - Google Patents

Description

  The present invention relates to a sustained release flocculant, a turbid water treatment method, and a method for producing a sustained release flocculant used for agglomeration and precipitation of suspended suspended solids (SS) in turbid water treatment.

  Mud drainage generated during construction works such as bridges in rivers and lakes, revetment works, and gravel collection work, contains a large amount of insoluble suspended solids (hereinafter referred to as “SS”). When discharging such mud drainage, it is necessary to remove suspended substances in advance based on regulations such as the Water Pollution Control Law so as not to adversely affect the living environment and ecosystem. Conventionally, inorganic and organic flocculants have been used for the removal of suspended substances. These flocculants are pH dependent and require pH adjustment during processing.

On the other hand, when focusing on SS removal, it is classified into a natural precipitation method that does not use a flocculant and a coagulation precipitation method that uses a flocculant.
Since the natural precipitation method does not use a flocculant, a stirrer or a flocculant injection pump is not necessary, and it is the simplest in terms of equipment. Not suitable for turbid water containing a large amount of SS with small particle size.

  In the coagulation-precipitation method, SS is made into a large floc by a flocculant, and the floc is settled in a sedimentation basin or thickener, so that even a suspended substance with a small particle size can be settled. Further, since it is necessary to install a pump or a stirrer for controlling the injection amount of the flocculant, the cost for capital investment required for muddy water treatment becomes high.

  In the coagulation precipitation method, as described above, inorganic and organic coagulants are conventionally used. Inorganic flocculants include aluminum-containing compounds such as aluminum sulfate, polyaluminum chloride (PAC), aluminum potassium sulfate or sodium aluminate, iron-containing compounds such as iron sulfate or iron chloride, or calcium-containing compounds such as quick lime or slaked lime. Technology using polyaluminum chloride, slaked lime, ferric chloride, etc. (see, for example, Patent Document 1), flocculant containing silica, quick lime as a main component, and containing chlorine, iron component, aluminum component (for example, patent) Reference 2), or a wastewater treatment agent containing magnesium chloride in addition to a sludge treatment agent containing a trivalent iron salt, a trivalent aluminum salt, a monovalent potassium salt and an alumina potassium salt (for example, patent document) 3) is known. On the other hand, examples of organic flocculants include cationic polymer flocculants such as polyacrylamide or sodium alginate (see, for example, Patent Document 4), anionic organic polymer electrolytes, cationic organic polymer electrolytes, and neutral inorganic ammonium. A flocculant formed by mixing a salt (for example, see Patent Document 5), or a flocculant composed of a natural organic acid and aluminum sulfate, and aluminum sulfate potassium, sodium carbonate, polyacrylamide, etc. (for example, see Patent Document 6). Etc. are known.

  However, since the above-mentioned flocculant has a high dissolution rate, it has a problem in sustaining the effect although it can exhibit a fast-acting effect, and it is necessary to maintain the flocculant concentration in order to maintain the effect. For example, when supplying the flocculant directly to the sand basin and the muddy water flow path to the sand basin, it is ideal to supply the flocculant in an amount necessary to precipitate SS, but it is difficult under flowing water conditions. Therefore, in order to maintain the effect, the actual condition is that the excess coagulant is supplied and SS is removed in consideration of the amount of the coagulant that flows out before the coagulation effect is obtained. As a result, not only the utilization rate of the flocculant is low, but also there is a concern that the flocculant component and the low pH treated water will flow out to the downstream area and adversely affect the living environment and the ecosystem. As a method for continuously dissolving the flocculant, for example, the particle diameter of the flocculant is increased, or the flocculant is gradually molded to harden the release rate of the flocculant into water. Examples include covering the substance with a film or maintaining the shape of the molded body with a binder, etc. Recently, a form in which the surface is coated with a coating material such as a resin using a flocculant as a core material has been studied. ing.

JP-A 64-90100 JP 2000-70608 A JP 2000-237800 A JP 63-267408 A Japanese Patent Publication No. 6-91922 JP 2005-118675 A

  The present invention provides a sustained-release flocculant, a muddy water treatment method, and a method for producing a sustained-release flocculant that suppress the outflow of excess flocculant components and low pH treated water while maintaining the flocculant effect over a long period of time. Is an issue.

  As a result of intensive studies to solve the above problems, the present inventors have released the water-soluble flocculant component by coating the surface of the water-soluble flocculant containing a specific metal-containing compound with a coating material containing a resin. It has been found that the speed can be adjusted and the above-mentioned problems can be solved, and the present invention has been completed.

That is, the present invention includes the following matters.
The sustained-release flocculant of the present invention is a coating material containing one or more resins, specifically a thermoplastic resin or a thermosetting resin, on the surface of a water-soluble flocculant containing a divalent or trivalent metal-containing compound. The water-soluble flocculant has a water solubility of 1 g / 20 ° C pure water 100 g or more.

The metal-containing compound is preferably a compound containing a metal selected from the group consisting of aluminum, iron and calcium.
The thermoplastic resin is preferably an olefin polymer, and the thermosetting resin is preferably a urethane resin, an epoxy resin, or an alkyd resin.

The coating material may further contain a filler and a surfactant.
Although the content rate of the said filler is not specifically limited, It is preferable that 10-80 mass% is contained with respect to a film, 20-80 mass% is more preferable, 30-80 mass% is especially preferable.
The content of the surfactant is not particularly limited, but is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass with respect to the coating. .
The coating material is 1 to 25% by mass, preferably 2 to 18% by mass with respect to 100% by mass of the water-soluble flocculant.

The muddy water treatment method of the present invention is obtained by coating the surface of a water-soluble flocculant containing a divalent or trivalent metal-containing compound with a coating material containing one or more kinds of resins. A slow-release flocculant that is 100 g or more of 1 g / 20 ° C. pure water is introduced into the sedimentation basin and the muddy water inflow passage to the sand basin, and the water-soluble flocculant is released into water in an amount in the range of 1 to 5 mg / L. It is characterized by doing.
In the sustained-release flocculant of the present invention, the method for coating the surface of the water-soluble flocculant is not particularly limited. For example, a method of spraying a molten resin and an additive (referred to as a resin) on a water-soluble flocculant, a method of spraying a solution or emulsion in which a resin or the like is dissolved or dissolved in a solvent on the surface of the water-soluble flocculant ( (Hereinafter referred to as “solution spraying method”), a method in which a powder such as resin is adhered to the surface of the water-soluble flocculant and melted to form a film, and a dip in which the water-soluble flocculant is immersed in a melt or solution such as resin It can be produced by a method such as spraying and dropping a coating material, followed by reaction curing to form a coating.

  The method for producing a sustained-release flocculant of the present invention includes (1) a step of flowing a water-soluble flocculant by an upward air flow at a temperature of 40 ° C. or higher, and (2) a thermoplastic resin in the water-soluble flocculant in the fluid state. A step of spraying the coating material solution and dispersion; (3) a step of removing the solvent from the coating material solution and dispersion adhering to the surface of the water-soluble flocculant by the spraying by ascending current; and (4) the ascending current of (3). Each step of separating and recovering the contained solvent from the air stream, wherein the coating coats the surface of the water-soluble flocculant with a thermoplastic resin.

  Specifically, a solid tower is separated from a jet tower having a water-soluble flocculant inlet at the top and a slow-release flocculant outlet at the bottom, and a gas discharged from the jet tower. A solid-gas separator that sends the removed gas to the condenser, a condenser that condenses and recovers the solvent contained in the gas sent from the solid-gas separator, and a heater that removes the solvent and the like from the condenser A slow-release flocculant circulating production apparatus having a blower that is introduced into the lower part of the jet tower and forms an upward air flow from the lower part of the jet tower and a heater that heats the gas sent from the blower A method for producing a sustained-release flocculant, wherein a solution obtained by dissolving or dissolving a coating material containing a thermoplastic resin in a solvent is added to the water-soluble flocculant charged from the water-soluble flocculant inlet. From the rectifier at the bottom of the tower through the spray nozzle Spray onto an air stream heated to a temperature of 40 ° C. or higher, preferably 40 to 200 ° C. toward the upper side of the flow tower, and form a coating layer having a thickness of 10 to 1000 μm on the outer periphery of the water-soluble flocculant in the upward air stream. In addition, the solvent is separated from the coating layer covering the water-soluble flocculant by the upward airflow formed in the jet tower, and the sustained-release flocculant is discharged from the lower part of the jet tower.

  In addition to the above, the method for producing the sustained-release flocculant of the present invention includes (1) a step of bringing the water-soluble flocculant into a fluid state or rolling state at a temperature of 20 ° C. to 100 ° C., and (2) a fluid state or rolling state. A step of coating a coating material containing a thermosetting resin on a moving water-soluble flocculant, (3) a step of forming an uncured coating layer made of the coating material on the surface of the water-soluble flocculant, and (4) forming The method comprises the steps of forming a film by thermally curing the uncured coating layer, wherein the film coats the surface of the water-soluble flocculant with a thermosetting resin.

   In the sustained release flocculant, the turbid water treatment method or the sustained release flocculant production method, the release rate represented by the following formula is required to be 80% by mass in water in a closed container at a water temperature of 25 ° C. The time is preferably 240 hours or more.

  If the sustained-release flocculant of the present invention is used, equipment for injecting the flocculant and the like are not required, and low pH treated water and excess flocculant components are unlikely to flow out while maintaining the flocculation effect over a long period of time. Muddy water treatment that has both effects is possible.

  That is, the sustained-release flocculant of the present invention can adjust the release rate of the flocculant component in muddy water by coating the water-soluble flocculant with high water solubility with a specific resin, so that the excess of the flocculant component It is possible to suppress pH reduction of treated water due to dissolution and outflow of excess components. The turbid water treatment method using such a sustained-release flocculant can be selected from various construction sites by selecting the flocculant release rate and its supply amount according to the turbidity and the flow rate of turbid water (space velocity SV). Can be easily implemented.

FIG. 1 is a flow sheet showing an example of an apparatus for producing a sustained-release flocculant. FIG. 2 is an example of a drawing disk (orifice) used in the manufacturing apparatus of FIG. FIG. 3 is an apparatus diagram of a column water flow test. FIG. 4 is a flow sheet showing an example of muddy water treatment.

Hereinafter, the sustained-release flocculant, the muddy water treatment method and the method for producing the sustained-release flocculant of the present invention will be described in detail.
In the present invention, “sustained release” means that the flocculant component effective for eliminating turbidity is continuously released or eluted, and the release rate represented by the above [Equation 1] is 80. It means that the time required for mass% is 240 hours or more.

[Slow release flocculant]
In the sustained-release flocculant of the present invention, the surface of a water-soluble flocculant containing a divalent or trivalent metal-containing compound is coated with one or more resins, specifically, a coating material containing a thermoplastic resin or a thermosetting resin. Thus, the water-soluble flocculant is a sustained-release flocculant having a water solubility of 1 g / 20 ° C. pure water of 100 g or more.

  The water-soluble flocculant is not particularly limited as long as it contains a divalent or trivalent metal-containing compound such as a general-purpose water-soluble aluminum-containing compound and is water-soluble. The divalent or trivalent metal-containing compound is a compound containing a metal selected from aluminum, iron and calcium, that is, at least one selected from divalent or trivalent aluminum salts, iron salts and calcium salts. Preferably there is. Specifically, aluminum sulfate, potassium aluminum sulfate, ammonium aluminum sulfate, polyaluminum chloride, ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, polyferric sulfate, calcium chloride, sulfuric acid Calcium, calcium carbonate, calcium nitrate, calcium alginate, calcium phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate or their double salts, inorganic polymer flocculants (active silicic acid, polysilica iron), natural organic polymer systems There are flocculants (sodium alginate / chitin / chitosan-based / bio-flocculants) and synthetic organic polymer-based flocculants (cation / anion / nonionic). Among these, aluminum sulfate, potassium aluminum sulfate, ammonium aluminum sulfate, polyaluminum chloride, ferric chloride, and polyferric sulfate are preferable. These double salts or a combination of two or more of these can also be used.

The coating material is one or more kinds of resin, and specifically includes a thermoplastic resin or a thermosetting resin.
Examples of the thermoplastic resin used in the present invention include olefin polymers, vinylidene chloride polymers, diene polymers, waxes, polyesters, petroleum resins, natural resins, oils and fats, modified products thereof, and urethane resins. .

  Examples of the olefin polymer include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-carbon monoxide copolymer, ethylene-hexene copolymer, ethylene-butadiene copolymer, polybutene, butene-ethylene copolymer. Polymer, butene-propylene copolymer, polystyrene, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide terpolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid ester copolymer, etc. Is mentioned.

Examples of the vinylidene chloride polymer include a vinylidene chloride-vinyl chloride copolymer.
Examples of the diene polymer include a butadiene polymer, an isoprene polymer, a chloroprene polymer, a butadiene-styrene copolymer, an EPDM polymer, and a styrene-isoprene copolymer.

Examples of waxes include beeswax, wood wax, and paraffin.
Examples of the polyester include aliphatic polyesters such as polylactic acid and polycaprolactone, and aromatic polyesters such as polyethylene terephthalate.

Examples of natural resins include natural rubber and rosin.
Examples of fats and oils and modified products thereof include cured products, solid fatty acids, and metal salts.

  The thermoplastic resin is preferably an olefin polymer, specifically, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-carbon monoxide copolymer, ethylene-hexene copolymer, ethylene-butene copolymer. More preferably, it is at least one selected from a polymer, an ethylene-octene copolymer, an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, and a propylene-butene copolymer.

The coating material can contain a filler or a surfactant as long as the effects of the present invention are not impaired.
Examples of the filler include talc, clay, kaolin, bentonite, sulfur, muscovite, phlogopite, mica-like iron oxide, metal oxide, siliceous, glass, alkaline earth metal carbonate, sulfate, and high water absorption. Examples include molecules and starch.

  Examples of the surfactant include nonionic surfactants typified by polyol fatty acid esters, nonionic surfactants, cationic surfactants, and anionic surfactants.

  Although the content rate of the said filler is not specifically limited, Preferably it is the range of 20-80 mass% with respect to 100 mass% of coating materials, More preferably, it is the range of 30-80 mass%. Within the above range, the film-forming properties and the elution rate controllability of the sustained-release flocculant are good.

  Although the content rate of the said surfactant is not specifically limited, Preferably it is the range of 0.01-10 mass% with respect to 100 mass% of coating materials, More preferably, it is 0.1-5 mass % Range. Surfactants are useful for improving the dispersibility of fillers in a solution or emulsion in which a coating material or the like is dissolved or dissolved in a solvent. If it is within the above range, the effect is sufficient and affects the dissolution rate control. I don't have to.

The coating only needs to have at least one resin-containing layer. For example, a filler such as sulfur may be used for the outer layer or the inner layer.
Examples of the thermosetting resin used in the present invention include phenol resin, furan resin, xylene-formaldehyde resin, ketone-formaldehyde resin, amino resin, alkyd resin, unsaturated polyester, epoxy resin, silicon resin, urethane resin and drying oil. Is mentioned. Among these, a urethane resin, an epoxy resin, or an alkyd resin is preferable.

The thermosetting resin is generally used in combination with a curing agent or a curing accelerator, but in the present invention, these combinations are not particularly limited.
The divalent or trivalent metal-containing compound and the water-soluble flocculant containing the same are as described above.

  The thermoplastic resin or thermosetting resin may be contained in a state of being mixed in the coating as long as the effects of the present invention are not impaired in addition to the individual use.

The amount of the coating material is 1 to 25% by mass, preferably 2 to 18% by mass, with respect to 100% by mass of the water-soluble flocculant. If the coating material is less than the lower limit, it is difficult to control the release rate, and if it exceeds the upper limit, the release rate tends to be slow, and the production cost is high, such as a decrease in the proportion of the flocculant component, which is not practical. .
The average particle diameter of the water-soluble flocculant particles for coating is 1 to 10 mm, preferably 1 to 5 mm. If the average particle size is within the above range, the productivity is good. If the average particle size is less than the lower limit, sticking between particles occurs during coating, and handling becomes worse. If the upper limit is exceeded, an air volume (energy) is required to maintain the jet state, which is not practical.

Moreover, the form of the above-mentioned sustained release flocculant is not particularly limited, but is preferably granular and more preferably spherical, from the viewpoint of stably controlling the release rate. Although there is no restriction | limiting in particular in the particle diameter of the water-soluble flocculant of this invention, Usually, it is 0.5-10 mm, Preferably it is 1-5 mm. The shape is preferably nearly spherical. Specifically, the sphericity coefficient obtained by the following formula is preferably 0.7 or more, more preferably 0.75 or more, and still more preferably 0.8 or more. The maximum value of the circularity coefficient is 1, and as the value approaches 1, the particle approaches a perfect circle, and the circularity coefficient decreases as the particle shape collapses from the perfect circle.
Circularity coefficient = {(4π × projection area of particle) / (length of contour of particle projection) ² }

[Muddy water treatment method]
In the muddy water treatment method of the present invention, the surface of a water-soluble flocculant containing a divalent or trivalent metal-containing compound is coated with a coating material containing one or more resins, specifically, a thermoplastic resin or a thermosetting resin. The water-soluble flocculant has a water-soluble flocculant having a water-solubility of 1 g / 20 ° C. and 100 g or more of pure water. Release the water-soluble flocculant in water in an amount ranging from 1 to 5 mg / L. When the concentration of the flocculant released into water is less than 1 mg / L, the aggregation effect cannot be obtained. When the concentration exceeds 5 mg / L, the aggregation effect is obtained, but the pH in the wastewater is lowered.

  The method for introducing the sustained release flocculant into the sedimentation basin and the turbid water inflow path to the sand basin is not particularly limited, as long as the sustained release flocculant can be efficiently contacted with the turbid water. Put a slow-release flocculant in a nylon bag, a resin net bag, etc., and install it uniformly in the settling basin or the muddy water flow path to the settling basin, or fill the muddy water inflow passage with the sustained-release flocculant Examples include a method of installing a column and passing turbid water through the column. For example, the method described in FIG. 4 may be used.

  The above-mentioned sustained release flocculant has a time required for the release rate represented by the following formula to be 80% by mass in water in a closed container at a water temperature of 25 ° C. for 240 hours or more, and 240 hours or more and 960 hours. The following range is more preferable.

放出率が８０質量％になるのに要する時間が２４０時間以上であれば従来の徐放性でない凝集剤と比べて過剰供給になりにくく、処理水のｐＨ低下も発生しにくい。また、９６０時間以内であれば、安定的に凝集効果得られ、かつ、凝集剤の使用量が多くなりすぎないことが期待できる。

If the time required for the release rate to be 80% by mass is 240 hours or more, it is difficult to excessively supply compared to a conventional flocculant that is not sustained-release, and the pH of the treated water is hardly lowered. Moreover, if it is within 960 hours, it can be anticipated that the coagulation effect is stably obtained and the amount of the coagulant used is not excessive.

Here, the specific example of the measuring method of discharge | release time is shown below.
5 g of the sustained-release flocculant is put into a polyethylene container with a lid, filled with 200 ml of distilled water and sealed. This container is stored in an incubator at 25 ° C., and the total amount of aluminum released into distilled water is measured every 7 days. The release rate of the sustained release flocculant is calculated by the following formula.

８０質量％放出時間とは、放出されたアルミニウム濃度の累積放出量が８０％になる時間である。

The 80 mass% release time is the time when the cumulative release amount of the released aluminum concentration is 80%.

  By performing turbid water treatment using the sustained-release flocculant of the present invention, the release rate of the flocculant component in the turbid water is adjusted, and the pH decrease of the treated water due to excessive dissolution of the flocculant component and the outflow of excess components are suppressed. In addition, simplification of the turbid water treatment facility and labor saving of the sustained-release flocculant application can be achieved. Furthermore, by using the above-mentioned sustained-release flocculant, various construction works can be performed by selecting the flocculant release rate and its supply amount according to the turbidity and the flow rate of turbid water (space velocity SV (Space Velocity)). It can be implemented easily on site.

  In addition, in the muddy water treatment method of the present invention, for example, aluminum sulfate, potassium aluminum sulfate, ammonium aluminum sulfate, polyaluminum chloride, and second chloride together with the above-mentioned sustained-release flocculant as long as the effects of the present invention are not impaired. A known flocculant such as iron or polyferric sulfate may be used.

[Method for producing sustained-release flocculant]
Although the manufacturing method of the sustained release flocculant of this invention is not specifically limited, A suitable method can be selected with coating material.

The sustained-release flocculant of the present invention includes the following steps (1) to (4), drops the water-soluble flocculant coated with a coating material containing a predetermined amount of thermoplastic resin, and discharges it from the lower part of the jet tower. Can be manufactured.
(1) A step of causing a water-soluble flocculant to flow by an ascending air current at a temperature of 40 ° C. or higher, preferably 40 to 200 ° C. (2) Spraying a coating material solution and dispersion containing a thermoplastic resin to the water-soluble flocculant in the fluid state (3) The step of removing the solvent by the rising air current from the coating material solution and dispersion adhering to the surface of the water-soluble flocculant by the spraying. (4) The solvent contained in the upward air current of (3) is separated and recovered from the air current. Step Specifically, the method for producing a sustained-release flocculant of the present invention includes a jet tower having a water-soluble flocculant inlet on the upper side and a slow-release flocculant outlet on the lower side, and the jet tower. A solid-gas separator that separates solids from the discharged gas and sends the gas from which solid foreign matters have been removed to the condenser, and a condenser that condenses and recovers the solvent contained in the gas sent from the solid-gas separator And the gas from which the solvent is removed by the condenser An apparatus for circulating and producing a sustained-release flocculant having a blower that is sent to a heater and introduced into the lower part of the jet tower to form an upward air flow from the lower part of the jet tower and a heater that heats the gas sent from the blower A method for producing a sustained-release flocculant using a solution obtained by dissolving or dissolving a coating material containing a thermoplastic resin in a water-soluble flocculant charged from the water-soluble flocculant inlet (hereinafter referred to as a water-soluble flocculant) , "The coating liquid") is sprayed from a rectifier at the bottom of the jet tower through an atomizing nozzle onto an air stream heated to a temperature of 40 ° C or higher, preferably 40 to 200 ° C. A coating layer having a thickness of 10 to 1000 μm is formed on the outer periphery of the water-soluble flocculant in the upward air flow, and the water-soluble flocculant is coated from the coating layer covered with the upper air flow formed in the jet tower. Separate the solvent into the air stream It can be produced by discharging the sustained release flocculant from the lower jet tower. The productivity is good when the temperature of the air flow when spraying the coating liquid is in the above range, but when it is less than 40 ° C., the solvent from the coating material solution and dispersion adhering to the surface of the flocculant is efficiently used. As a result, since the solvent remains (insufficient drying), the film-forming property of the coating is impaired, and adhesion between grains occurs. On the other hand, when the temperature exceeds 200 ° C., troubles such as softening of the resin and adhesion of grains occur.

Here, the temperature of the water-soluble flocculant in the jet state when spraying the coating liquid is preferably 40 to 80 ° C.
An example of an apparatus for producing a sustained-release flocculant used in the present invention will be described. As shown in FIG. 1, the jet tower 1 has a tower diameter (inner diameter) of 1,300 mm, a height of 8,500 mm, and a cone angle of 50 degrees, and includes a water-soluble flocculant inlet 15 and a sustained-release flocculant. It has a discharge port 13. The spray nozzle 2 is a full-contained one-fluid spray nozzle, and 3 is a water-soluble flocculant. 6 is a solid-gas separator and 7 is a condenser. 8 is a blower (roots type), 12 is a heater. 9 is a coating material mixing dissolution tank (dissolution tank) with a stirrer, and 10 is a liquid feed pump (diaphragm type). Reference numeral 14 denotes a guide tube (diameter 300 mm, length 1,760 mm, fluororesin-coated product), and 11 denotes a rectifying can. 21 is an aperture disk. FIG. 2 shows details of the throttle disk 21. The throttle disk 21 has a diameter of 154 mm, an inner diameter of the ejection hole 23 of 45 mm, the number of ejection holes of 4 (aperture ratio of 34%), and a spray nozzle at the center of each ejection hole 23. 2 is provided. The spray nozzle 2 is arranged on a circle having a diameter of 95 mm with the center of the diaphragm disk 21 as the center.

In the above apparatus, the water-soluble flocculant 3 is introduced from the water-soluble flocculant inlet 15 while the air kept at the airflow temperature of 150 ° C. in the jet hole 23 is sent to the jet tower 1 using the blower 8, The flocculant 3 is brought into a jet state. At this time, the flow rate and temperature of the heated airflow are adjusted so that the temperature of the water-soluble flocculant is 70 ± 5 ° C. When the temperature is raised to 70 ± 5 ° C., the coating liquid is sprayed from the spray nozzle 2 onto the water-soluble flocculant in a mist state and in a jet state by the liquid feeding pump 10. At this time, the flow rate of the airflow is adjusted while measuring with a flow meter installed between the blower 8 and the rectifier 11, and the temperature of the heated airflow is measured by measuring the temperature of the water-soluble flocculant and the temperature at the outlet of the jet tower. Adjust while adjusting. The circulating air volume is 3,000 m ³ / h, and the flocculant charge is 1,000 kg. When a predetermined amount of coating liquid is supplied, the blower 8 is stopped and the coated water-soluble flocculant is withdrawn from the product outlet 13 to obtain a sustained-release flocculant.

  In addition, the said manufacture example shows an example of the manufacturing method of the sustained release flocculant of this invention, and manufacturing conditions etc. are not limited to this. For example, in the production method described above, the water-soluble flocculant may be brought into a fluid state by a fluidizer or a jet fluidizer.

The method for producing a sustained-release flocculant of the present invention includes the following steps (1) to (4), and the film containing a thermosetting resin is 1 to 25% by mass with respect to 100% by mass of the water-soluble flocculant. It is characterized by being.
(1) A step of bringing a water-soluble flocculant into a fluidized state or a rolling state at a temperature of 20 ° C. to 100 ° C. (2) A coating material containing a thermosetting resin is coated on the water-soluble flocculant in a fluidized state or a rolling state. Step (3) A step of forming an uncured coating layer made of the coating material on the surface of the water-soluble flocculant (4) A step of thermally curing the formed uncured coating layer to form a coating film. Spraying may be performed by dropping or spraying a mixed solution of a polyol component and a polyisocyanate component, or by dropping or spraying each of them alternately or simultaneously without mixing the polyol component and the polyisocyanate component. As a method of dripping or spraying the polyurethane material, continuous dripping, spraying using a one-component or two-component nozzle, two-fluid nozzle using gas, and the like can be used. In addition, when the temperature at which the water-soluble flocculant is in a fluidized state or in a rolling state is in the above range, the manufacturability is good, but if it is less than 20 ° C., the curing reaction of the coating material adhering to the surface of the flocculant is slow. Sticking occurs. On the other hand, when the temperature exceeds 100 ° C., the film-forming property is impaired because the curing reaction is fast.

  That is, in the above production method, the water-soluble flocculant is brought into a rolling state by a rotating pan, a rotating drum, etc., and a curing agent or a curing accelerator necessary for a coating material containing a thermosetting resin is dropped and sprayed. A sustained-release flocculant can be produced by adding to the water-soluble flocculant by a method, coating the surface of the water-soluble flocculant, and forming a film.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to this.
<Measurement of water solubility>
1 g each of the divalent or trivalent metal-containing compound was added to 100 g of pure water at 20 ° C. in a 200 ml pure water beaker with stirring. Table 3 shows that the case where there was a precipitate after stirring for 3 minutes and standing was determined to be insoluble (X), and the case where there was no precipitate was determined to be soluble (O).

以下、実施例および比較例で用いられた水溶性凝集剤は、水溶性が１ｇ/２５℃純水１００ｇ以上であるＦ１〜Ｆ２を使用した。

Hereinafter, the water-soluble flocculants used in Examples and Comparative Examples used F1 to F2 whose water-solubility is 100 g or more at 1 g / 25 ° C. pure water.

[Production of sustained-release flocculant]
The water-soluble flocculant F1 was coated by the following method to obtain flocculants C1 to C13 having different water-soluble flocculant component release rates.

<Production device 1>
The structure of the manufacturing apparatus 1 is the same as that of the flow sheet of FIG. 1, and the spout tower 1 has a tower diameter (inner diameter) of 1,300 mm, a height of 8,500 mm, and a cone angle of 50 degrees. It has an agent inlet 15 and a product outlet 13. The spray nozzle 2 is a full-contained one-fluid spray nozzle, and 3 is a water-soluble flocculant (core material). 6 is a solid-gas separator and 7 is a condenser. 8 is a blower (roots type), and 12 is a heater. 9 is a coating material mixing dissolution tank (dissolution tank) with a stirrer, and 10 is a liquid feed pump (diaphragm type). Reference numeral 14 denotes a guide tube (diameter 300 mm, length 1,760 mm, fluororesin-coated product), and 11 denotes a rectifying can. 21 is an aperture disk.

  Details of the aperture disk 21 are shown in FIG. In FIG. 2, the diameter is 154 mm, the inner diameter of the ejection hole 23 is 45 mm, the number of ejection holes is 4 (aperture ratio 34%), and the spray nozzle 2 is provided at the center of each ejection hole 23. The spray nozzle 2 was arranged on a circle having a diameter of 95 mm with the center of the diaphragm disk 21 as the center.

<Manufacturing method 1>
A coated flocculant was produced using the production apparatus 1 under the following conditions. That is, the heated airflow flows from the lower part to the upper part of the jet tower 1, passes through the solid-gas separator 6, cools the airflow with the condenser 7, and condenses and recovers the organic solvent. The air stream from which the organic solvent has been separated and removed by the condenser 7 is circulated so as to pass through the heater 12 from the blower 8 and be heated and led again to the jet tower 1 as a high temperature air stream. First, using the blower 8, the water-soluble flocculant 3 is introduced from the flocculant inlet 15 while air kept at an airflow temperature of 150 ° C. at the outlet 23 is sent to the jet tower 1. It was in a jet state. At this time, the flow rate and temperature of the heated air stream were adjusted so that the temperature of the water-soluble flocculant was 70 ± 5 ° C. When the temperature was raised to 70 ± 5 ° C., the coating liquid in which the coating material was dissolved and dispersed was sprayed from the spray nozzle 2 onto the coagulant in a mist-like jet state by the liquid feeding pump 10. At that time, the flow rate of the air flow is adjusted while measuring with a flow meter installed between the blower 8 and the rectifier 11, and the temperature of the heated air flow is measured by measuring the temperature of the water-soluble flocculant and the temperature at the outlet of the jet tower. Adjusted. The circulating air volume was 3,000 m ³ / h, and the flocculant charge was 1,000 kg. When a predetermined amount of the coating solution was supplied, the blower 8 was stopped and the flocculant was extracted from the product discharge port 13 to obtain a coated flocculant.

[Example 1-9, Comparative Examples 3-4 and Reference Example 1-2]
A coating solution was prepared by dissolving and dispersing the coating material having the composition shown in Table 2 in 95% by mass of an organic solvent (tetrachloroethylene). The coated flocculants C1 to C13 were produced by coating the surface of the water-soluble flocculant F1 with the coating liquid using the production apparatus.

  As the thermoplastic resin used in this example, general-purpose low-density polyethylene and ethylene-vinyl acetate copolymer were used.

＜製造装置２＞
製造装置２として、熱風発生機を付設した温度制御可能な傾斜パン型転動造粒機（パン径４５０ｍｍ）を用いた。

<Manufacturing device 2>
As the production apparatus 2, a temperature-controllable tilting bread type rolling granulator (pan diameter 450 mm) equipped with a hot air generator was used.

<Manufacturing method 2>
A sustained release flocculant was produced by the following method using the production apparatus 2 described above. 920 g of the water-soluble flocculant was charged into the production apparatus 2 and rotated at 20 to 45 RPM, so that the water-soluble flocculant was in a rolling state. The apparatus was heated to maintain the temperature of the water-soluble flocculant at 65 to 75 ° C. to maintain the rolling state. Polyol and polyisocyanate as raw materials for the thermosetting resin and 0.8 g of dimethylethanolamine as the amine catalyst are mixed, and each of the water-soluble flocculants heated by using a liquid feed pump and in a rolling state for 40 minutes. And coated. Thereafter, the temperature of the water-soluble flocculant was maintained in the range of 65 to 75 ° C. for 10 minutes to obtain a coated flocculant.

[Examples 10 to 12 ]
According to the coating material having the composition shown in Table 3 and the coating weight (mass% of the coating film with respect to the aggregating agent to be coated), the aggregating agents C14 to C16 coated using the manufacturing apparatus 2 were manufactured. F1 was used as the water-soluble flocculant to be coated.

［濁水処理に要するアルミニウム濃度についての評価］
高濃度濁水（浮遊物質（ＳＳ）濃度２５００ｍｇ／Ｌ）および低濃度濁水（浮遊物質（ＳＳ）濃度１００ｍｇ／Ｌ）に、アルミニウム濃度がそれぞれ２、５および１０ｍｇ／Ｌとなるように硫酸アルミニウムを添加し、よく攪拌混合した。

[Evaluation of aluminum concentration required for muddy water treatment]
Aluminum sulfate is added to high-concentration turbid water (suspended matter (SS) concentration 2500 mg / L) and low-concentration turbid water (suspension matter (SS) concentration 100 mg / L) so that the aluminum concentration becomes 2, 5 and 10 mg / L, respectively. And mixed well with stirring.

Muddy water containing aluminum sulfate was placed in a 1 L beaker and stirred by reciprocal shaking, and then allowed to stand at room temperature of 25 ° C.
After standing, 50 to 200 mL of a 10 cm portion from the water surface was collected with a pipette after 1, 10, 30, 60, 240, and 1440 minutes, and the SS concentration was measured to determine the sedimentation rate.

  Table 4 shows the evaluation results for the aluminum concentration required for muddy water treatment.

上記結果から、アルミニウム濃度が２〜５ｍｇ/Ｌの範囲であれば、凝集沈殿が達成できることがわかる。また、高濃度濁水の場合、５ｍｇ/Ｌ以上添加しても、それ以上沈降速度は上がらず、低濃度濁水の場合、２ｍｇ/Ｌ以上添加しても沈降速度は上がらないことがわかる。

From the above results, it can be seen that aggregation precipitation can be achieved when the aluminum concentration is in the range of 2 to 5 mg / L. In addition, in the case of high-concentration turbid water, it can be seen that even when 5 mg / L or more is added, the sedimentation rate does not increase any more, and in the case of low-concentration turbid water, the sedimentation rate does not increase even if 2 mg / L or more is added.

[Characteristic evaluation of flocculant]
(1) Release characteristics of flocculant (80% by mass release time)
5 g of the flocculant (C1 to C16) was placed in a polyethylene lidded container, filled with 200 ml of distilled water and sealed. This container was stored in an incubator at 25 ° C., and the total amount of aluminum released into distilled water every 7 days was measured. The release rate of the sustained release flocculant was calculated by the following formula. The 80 mass% release time is the time when the cumulative release amount of the released aluminum concentration is 80%.

放出率が８０％になるのに要する時間が２４０時間以上９６０時間以下であるものを放出特性良好（○）とし、放出率が８０％になるのに要する時間が２４０時間未満であるものを放出特性不良（×）、９６０時間を超えているものを放出特性適（△）と判定した。

What time required for the release rate becomes 80% or less 240 hours or more 960 hours and release characteristics good (○), releasing those time required for the release rate of 80% are less than 240 hours poor characteristics (×), and determined that 9 out release what is more than 60 hours properties suitable (△).

  Table 5 shows the evaluation results of the 80 mass% release time of the flocculant.

Ｃ１０、Ｃ１２の放出率が８０％になるのに要する時間は２４０時間未満であり、Ｃ１１、Ｃ１３、Ｃ１５およびＣ１６の放出率が８０％になるのに要する時間は９６０時間を超えた。
（２）凝集剤の溶解特性（カラム通水試験）
図３に示す装置を用いて、Ｃ１〜４、Ｃ１０〜１１、Ｃ１４〜１６およびＦ１〜２の凝集剤の溶解特性を評価した。すなわち、円筒カラム２４（内径１０ｃｍ、長さ９ｃｍ）に、各層の体積が１層目２７にガラスビーズが３１４ｃｍ³、２層目２８に凝集剤が７８．５ｃｍ³、３層目２９にガラスビーズが３１４ｃｍ³となるよう層状に詰めた。上記状態の円筒カラム２４に、貯水タンク３１より送液ポンプ２５にて送液管２６から円筒カラム２４に所定の流速で蒸留水を通水した（通水条件：ＳＶ＝２５０）。通水してから５分後および１０分後に排出管３０より排出された蒸留水をそれぞれサンプリングした。

The time required for the C10 and C12 release rates to be 80% was less than 240 hours, and the time required for the C11, C13, C15, and C16 release rates to be 80% exceeded 960 hours.
(2) Solubility of flocculant (column flow test)
Using the apparatus shown in FIG. 3, the dissolution characteristics of C1-4, C10-11, C14-16 and F1-2 flocculants were evaluated. That is, the cylindrical column 24 (inner diameter 10 cm, length 9cm), the glass beads 314 cm ³ in each layer of the volume of first layer 27, second layer coagulant 28 is 78.5 cm ^3, 3-layer 29 to the glass beads Was packed in layers so as to be 314 cm ³ . Distilled water was passed through the cylindrical column 24 in the above state from the water storage tank 31 by the liquid feed pump 25 from the liquid feed pipe 26 to the cylindrical column 24 at a predetermined flow rate (water flow condition: SV = 250). Distilled water discharged from the discharge pipe 30 after 5 minutes and 10 minutes after passing water was sampled.

  Table 6 shows the results of the dissolution characteristics of the flocculant.

［ジャーテスト試験］
実施例１〜２、比較例３および参考例１についてジャーテスト試験を行い、濁水処理効果を検証した。すなわち、高濃度濁水（浮遊物質濃度２５００ｍｇ/Ｌ）および低濃度濁水（１００ｍｇ/Ｌ）を５００ｍＬずつビーカーに採取し、凝集剤Ｃ１、Ｃ２、Ｃ１０およびＣ１１を投入した。これらを回転数を１５０ｍｉｎ^-1に設定したジャーテスター中で２０分間攪拌した後、３０分静置した。３０分後、上澄み液を採取し、清澄度の観察、浮遊物質（ＳＳ）濃度およびｐＨを測定した。

[Jar test]
The jar test test was conducted about Examples 1-2 , the comparative example 3, and the reference example 1 , and the muddy water treatment effect was verified. That is, a high concentration turbid water (suspended solids concentration 2500 mg / L) and low concentration turbid water (100 mg / L) were taken into a beaker by 500 mL, was charged flocculant C1, C2, C 10 and C 11. These were stirred for 20 minutes in a jar tester with the number of revolutions set to 150 min ⁻¹ and then allowed to stand for 30 minutes. After 30 minutes, the supernatant was collected and observed for clarity, suspended matter (SS) concentration and pH.

  Table 7 shows the test results of the jar test.

表５に示すように、実施例１〜２では清澄度、濁水処理効果およびｐＨともに良好であった。比較例３は清澄度、濁水処理効果は認められるが、ｐＨが５．８以下となり濁水処理方法として好ましくない。参考例１では清澄度、濁水処理効果が認められなかった。

As shown in Table 5, in Examples 1 and 2, the clarity, turbid water treatment effect, and pH were both good. In Comparative Example 3, the clarity and turbid water treatment effect are recognized, but the pH is 5.8 or less, which is not preferable as a turbid water treatment method. In Reference Example 1 , the clarity and muddy water treatment effects were not recognized.

1. Jet tower 2. 2. Spray nozzle Water-soluble flocculant (core material)
4). Circulating air flow piping5. 5. Coating liquid supply pipe 6. Solid-gas separator Condenser 8. Blower 9 Coating material mixing dissolution tank (dissolution tank)
10. Liquid feed pump 11. Rectification can 12. Heater 13. Product outlet 14. Guide tube 15. Water-soluble flocculant (core material) inlet 21. Diaphragm disc 22. Main disc 23. Ejection hole 24. Cylindrical column 25. Liquid feed pump 26. Liquid feed tube 27.1 1st layer (glass beads)
28. Second layer (flocculating agent)
29. 3rd layer (glass beads)
30. Discharge pipe 31. Water storage tank 32. Sedimentation basin 33. Muddy water inlet 34. Flocculant 35. Current plate 36. Contact filter medium 37. Oil adsorption mat 38. Outlet 39. Land of creation

Claims (6)

A bag containing a sustained-release flocculant formed by coating the surface of a water-soluble flocculant containing a divalent or trivalent metal-containing compound with a coating material containing one or more thermoplastic resins, A turbid water treatment method, wherein the water-soluble flocculant is discharged into water in an amount in the range of 1 to 5 mg / L.
Here, the sustained-release flocculant is coated with a coating material in an amount of 1 to 25% by mass with respect to 100% by mass of the water-soluble flocculant,
The coating material contains 20 to 80% by mass of filler,
In water closed system in the container of the water temperature 25 ° C., you wherein the time required for the release rate of the following formula is 80% by weight in the range of less 240 hours or more 960 hours.

The thermoplastic resin is polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-carbon monoxide copolymer, ethylene-hexene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, ethylene-vinyl acetate. The muddy water treatment method according to claim 1, which is at least one selected from a copolymer, an ethylene-ethyl acrylate copolymer, and a propylene-butene copolymer . The muddy water treatment method according to claim 1 or 2, wherein the thermoplastic resin is a mixture of polyethylene and an ethylene-vinyl acetate copolymer . Turbid water inflow into a settling basin and settling basin using a bag containing a sustained release flocculant formed by coating the surface of a water-soluble flocculant containing a divalent or trivalent metal-containing compound with a coating material made of urethane resin A muddy water treatment method, wherein the water-soluble flocculant is discharged into water in an amount in the range of 1 to 5 mg / L.
Here, the sustained-release flocculant is coated with a coating material in an amount of 1 to 25% by mass with respect to 100% by mass of the water-soluble flocculant,
In water closed system in the container of the water temperature 25 ° C., you wherein the time required for the release rate of the following formula is 80% by weight in the range of more than 240 hours.

1 wherein the water-soluble flocculant containing the divalent or trivalent metal-containing compound is selected from divalent or trivalent iron salts, calcium salts, and aluminum salts having a water solubility of 1 g / 20 ° C. and 100 g or more of pure water. It is a seed | species or more, The muddy water processing method as described in any one of Claims 1-4 characterized by the above-mentioned . The muddy water treatment method according to any one of claims 1 to 5, wherein the water-soluble flocculant contains an aluminum salt .

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