TWI564252B - A water treatment device and a water treatment method - Google Patents

Description

Water treatment device and water treatment method

Embodiments of the invention relate to water treatment devices and water treatment methods.

Recently, with the development of industry and the increase in population, the effective use of water resources has been continuously required. In order to pursue the effective use of water resources, how to purify and reuse various wastewaters such as industrial wastewater and domestic wastewater has become more important.

In order to purify the wastewater, it is necessary to separate and remove water insoluble matter and impurities contained in the water. The method for purifying the wastewater includes, for example, a membrane separation method, a centrifugal separation method, an activated carbon adsorption method, an ozone treatment method, and a precipitation removal method of a floc added with a flocculant. By these water treatment methods, it is possible to remove oils, clays, and the like which are highly concentrated in the environment and are dispersed in water, such as phosphorus and fluorine contained in the wastewater. In particular, phosphorus and fluorine can be reused as fertilizer and washing water, and these substances are removed from waste water, and are also extremely important from the viewpoint of resource recycling.

Among them, membrane separation is one of the most commonly used methods for removing insoluble matter in water, from the viewpoint of membrane protection, and improving the inclusion of difficult dehydration. From the viewpoint of the water passing rate of the water of the substance, a method of using the filtering auxiliary material is usually employed.

Further, a method of removing fluoride ions from water, for example, Patent Document 1 describes a technique in which calcium fluoride is added to water to form calcium fluoride and calcium fluoride sludge is precipitated by adding a flocculating agent. Patent Document 2 describes a technique in which fine calcium fluoride obtained by pulverizing the calcium fluoride is returned to a reaction tank for producing calcium fluoride, and is used as a seed crystal to form large calcium fluoride and precipitate it. . Patent Document 3 describes a technique in which fluoride ions are precipitated from calcium fluoride and calcium phosphate, and a polymer flocculant is added to recover sludge of the precipitates.

However, in the technique described in Patent Document 1, since the precipitated calcium fluoride and the large scum of the flocculant are recovered, the purity of the recovered calcium fluoride is lowered, and it is difficult to recover a valuable substance. There is a problem that the amount of sludge increases due to the incorporation of the flocculating agent. Further, in Patent Document 2, since a part of the precipitated calcium fluoride is returned as a crystal nucleus to recover larger particles, although the flocculant may not be used to avoid the problem of an increase in the amount of sludge, there is a need to It takes a long time to grow into a large enough crystal. Further, as shown in Patent Document 3, when calcium phosphate is formed, it is difficult to separate the calcium phosphate from water, and it is necessary to use a polymer flocculant in combination.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2010-207755

[Patent Document 2] Japanese Patent Laid-Open No. 2010-110688

[Patent Document 3] Japanese Patent No. 2005-296837

The problem to be solved by the present invention is to remove and recover the fluoride ion at a low cost, efficiently, and efficiently from a wastewater containing fluoride ions.

The water treatment device of the embodiment has a filter auxiliary material storage tank for storing the slurry of the filter auxiliary material, and a downstream side of the filter auxiliary material storage tank for measuring the specific amount supplied by the filter auxiliary material storage tank. a filtering auxiliary material metering tank of the mud; and a pre-coating layer formed by the filtering auxiliary material in the slurry supplied from the filtering auxiliary material metering tank on the downstream side of the filtering auxiliary material metering tank, and the inside is formed A solid-liquid separation device that divides the space into upper and lower filters. Further, the present invention includes: a treated water storage tank that supplies the treated water containing calcium fluoride to the upstream side of the solid-liquid separation device; and a downstream side of the solid-liquid separation device for the solidification a filter auxiliary material and a washing water storage tank for supplying the washing water to the upper portion of the filter of the liquid separation device, and storing the filter auxiliary material obtained by destroying the pre-coating layer together with the washing water; and filtering from the foregoing The auxiliary material and the washing water storage tank are the first return line for returning the filtering auxiliary material and the washing water to the treated water storage tank. Moreover, it is disposed between the treated water storage tank and the solid-liquid separation device to concentrate the aforementioned portion a sedimentation tank of the calcium fluoride contained in the water; a second return line for returning the calcium fluoride slurry obtained in the sedimentation tank from the sedimentation tank to the treated water storage tank; and located downstream of the sedimentation tank a concentrating tank for transferring a predetermined amount of the calcium fluoride slurry obtained in the foregoing sedimentation tank and concentrating the slurry; and a downstream side of the concentration tank for drying the slurry concentrated by the concentration tank Dehydrator.

10‧‧‧Water treatment unit

11‧‧‧Filter auxiliary storage tank

12‧‧‧Filter auxiliary material metering tank

13‧‧‧Solid-liquid separation device

14‧‧‧pH adjustment tank

15‧‧‧Reaction tank

16‧‧‧Sedimentation tank

17‧‧‧Additional treated water conditioning tank

18‧‧‧Processing water storage tank

19‧‧‧Filter auxiliary material and washing water storage tank

21‧‧‧concentration tank

22‧‧‧Dehydrator

31~39, 41~48‧‧‧ piping

51~57‧‧‧ pump

131‧‧‧Filter

132‧‧‧Pre-coating

W1‧‧‧ treated water

W2‧‧‧ treated water

Fig. 1 is a schematic configuration diagram of a water treatment device according to an embodiment.

(Filtering aids)

First, the filter auxiliary material used in the water treatment device and the water treatment method of the present embodiment will be described.

The filter auxiliary material of the present embodiment may be composed of, for example, inorganic particles. In addition, the "inorganic particles" in the present embodiment mean inorganic compound particles other than metal particles and metal particles.

The metal particles may be, for example, metals such as aluminum, iron, copper, and the like. Further, the inorganic compound particles may be, for example, magnetite, ilmenite, magnetic pyrite, magnesium ferrite, cobalt oxide iron, nickel oxide iron, oxygen magnetium, molten vermiculite, crystallite, glass, Talc, alumina, calcium silicate, calcium carbonate, barium sulfate, magnesium, tantalum nitride, boron nitride, nitride Ceramic particles such as aluminum, magnesium oxide, cerium oxide, and mica.

In particular, the filter auxiliary material can be formed by particles such as magnetite, ilmenite, magnetic pyrite, magnesium ferrite, cobalt ferrite iron, nickel ferrite iron, or oxygen magnetium, and can be easily performed by magnetic force. The regeneration of the filter auxiliary material described below.

Among the above particles, magnetic particles composed of a ferrite-based iron compound excellent in water stability are more preferable. For example, magnetite triiron tetroxide (Fe ₃ O ₄ ) is preferred because it is not only inexpensive, but also has a stable magnetic body and a safe element in water.

In this case, the particles may have various shapes such as a spherical shape, a polyhedron shape, and an amorphous shape, and are not particularly limited. Further, the particle size and shape can be appropriately selected in consideration of the manufacturing cost and the like.

In particular, when the inorganic particles are magnetic particles having an acute angle, the magnetic auxiliary filter-recovering process as described below can be carried out by magnet plating or plating if the magnetic force acts on the core and the filter auxiliary material can be regenerated by magnetic force. The surface treatment of Ni or the like and the usual plating treatment for the purpose of preventing corrosion and the like, and the above-mentioned acute angles are rounded and used.

When the filter auxiliary material is composed of magnetic particles, the size thereof is changed in accordance with the magnetic force, the flow rate, and the adsorption method of the processing equipment, and the optimum range thereof depends on the density of the magnetic particles and various conditions. However, the average particle diameter of the magnetic particles of the present embodiment is generally 0.1 to 100 μm, and more preferably in the range of 0.3 to 50 μm. When the lower limit of the magnetic particles is less than 0.1 μm, the magnetic particles are tightly aggregated to remove the water. The fine floats, however, in practice, sometimes it is not possible to get enough water. When the upper limit of the magnetic particles is larger than 100 μm, the distance between the particles becomes large, and the floating matter in the water to be removed may not be sufficiently removed.

In addition, the method of measuring the average particle diameter of the magnetic particles can be measured by a laser diffraction method. Specifically, it can be measured by a SALD-3100 type measuring device (trade name) manufactured by Shimadzu Corporation. In the following, when the "average particle diameter" appears and a specific numerical value is described, the "average particle diameter" is measured by the above-described laser diffraction method unless otherwise specified.

Further, in terms of the relevant elements of the above magnetic particles, although there are some errors depending on the type of the other inorganic particles as described above, they are sufficiently applicable.

Further, it is not necessary for the filter auxiliary material to be entirely composed of inorganic particles. In other words, when the filter auxiliary material contains magnetic particles, styrene resin, water-added styrene resin, butadiene resin, isoprene may be used as long as a magnetic force acts between the magnetic particles and the magnetic auxiliary material can be recovered by magnetic force. A binder such as a resin, an acrylonitrile resin, a cycloolefin resin, a phenol resin, or an alkyl methacrylate resin is used. Further, the surface of the magnetic particles may be bonded by an alkoxysilane compound such as methyltrimethoxydecane, methyltriethoxydecane, benzenetrimethoxydecane or phenyltriethoxydecane.

In this case, when the average particle diameter of the primary particles such as the magnetic particles is A (μm) and the average particle diameter of the aggregate obtained by combining the resin and the decane coupling agent is B (μm), A<B≦20A The range is preferably, preferably in the range of A < B ≦ 8A. When the conditions of the latter are met, The primary particles such as magnetic particles do not aggregate into a spherical shape to form an aggregate and obtain a twisted shape agglomerate.

Therefore, by using such an aggregate as a filtering aid and forming a pre-coating layer described later with the filtering auxiliary material, since the pre-coating layer has a moderate gap, the floating matter in the water can be sufficiently captured and removed. Moreover, it is possible to ensure a sufficient amount of water. Further, for the purpose of obtaining the effect, it is preferable to satisfy the relationship of A<B≦5A.

Further, when the aggregate is composed of a resin as a binder, the thickness C of the resin layer constituting the aggregate skin is preferably 0.01 μm or more and 0.25 μm or less. When the thickness C of the resin layer is less than 0.01 μm, the strength of the above aggregate is lowered, and it may be difficult to use it as a filter auxiliary material. When the thickness C of the resin layer is larger than 0.25 μm, the gap between the aggregates is too narrow, and it is used as a filter aid. When using materials, sometimes it is impossible to ensure effective water flow.

Further, the thickness C of the resin layer can be obtained by observation with an optical microscope, SEM, or the like. However, it is preferable to heat the aggregate to a specific temperature in an oxygen-free state, and to obtain a weight reduction amount during thermal decomposition of the aggregate. The amount of coating of the resin is taken, and the average value of the amount of coating of the resin is derived from the specific surface area of the aggregate, whereby it can be obtained more accurately.

The filter auxiliary material of the present embodiment can be produced by any method as long as it meets the requirements described above. For example, when the filter auxiliary material is composed of inorganic particles such as magnetic particles, inorganic particles which are commercially available in accordance with the above average particle diameter can be used as they are.

In addition, the filtering aid is configured by the agglutination as described above. In the case of the material, for example, inorganic particles such as magnetic particles and a resin may be dissolved or dispersed in an organic solvent, and the obtained solution or dispersion solvent may be sprayed by a spray drying method or the like. According to this method, the average particle diameter of the aggregate can be adjusted by adjustment of the ambient temperature and the discharge speed of the spray drying, and pores can be formed when the organic solvent is removed from the aggregate, and a porous aggregate can be formed.

On the other hand, in the case of manufacturing a filter auxiliary material for an aggregate, for example, a solution obtained by dissolving a resin or the like is poured into a mold filled with magnetic particles in advance, and the solvent is removed and solidified, or is dispersed. The composition of the polymer solution of the magnetic body is removed by the organic solvent and solidified, whereby the filter auxiliary material as described above can be obtained. In addition, after the inorganic particles such as magnetic particles are placed in a Henschel mixer, a ball mill, a granulator, or the like, a solution obtained by dissolving or dispersing a resin or the like in an organic solvent or a dispersion medium is dropped into the apparatus and dried. A filter aid as described above was obtained.

(water treatment device and water treatment method)

Fig. 1 is a schematic configuration diagram of a water treatment device of the present embodiment. The water treatment device 10 shown in Fig. 1 includes a filter auxiliary material storage tank 11 for storing the filter auxiliary material, and a downstream side of the filter auxiliary material storage tank 11 for measuring a specific amount of the filter auxiliary material. The filter auxiliary slurry transferred from the storage tank 11 is transferred to the filter auxiliary material metering tank 12 on the downstream side; and on the downstream side of the filter auxiliary material storage tank 11 and the filter auxiliary material metering tank 12, and is horizontal with respect to the installation surface. Surface filter 131, the internal space is divided by the filter 131 into solid-liquid separation devices (horizontal filters) 13 of the upper and lower portions 13A and 13B.

Further, by making the filter 131 and the installation surface in the solid-liquid separation device 13 horizontal, the thickness of the pre-coat layer formed later is uniform, so that a stable water amount and water quality can be obtained.

The filter 131 can be composed, for example, of a filter cloth, a metal mesh, a porous ceramic, a porous polymer, or the like. In particular, a filter cloth is preferable, and for example, a material such as polypropylene, nylon, or polyester is used as a double layer. Weaving cloth, twill weave, plain weave, satin weave, etc.

Further, on the upstream side of the solid-liquid separation device 13, a pH adjustment tank 14 for the purpose of promoting the subsequent conversion of calcium fluoride, adjusting the pH of the water to be treated W1 such as wastewater, and the pH adjustment tank are provided. On the downstream side of the 14th, a reaction tank 15 for converting fluoride ions in the water W1 to be treated into calcium fluoride by adding a calcium-insoluble inorganic substance which is insoluble in water to the water to be treated W1 is disposed. In the present embodiment, the pH adjusting tank 14 and the reaction tank 15 constitute a treated water storage tank.

Further, the treated water storage tank may be formed of, for example, the pH adjusting tank 14 and the reaction tank 15 as described above by the reaction tank 15, and the calcium fluoride may be simultaneously used in the reaction tank 15. Generation and pH adjustment.

Further, on the upstream side of the solid-liquid separator 13 on the downstream side of the reaction tank 15, a sedimentation tank 16 for the purpose of precipitating and separating the calcium fluoride obtained in the reaction tank 15 is disposed, and is solidified on the downstream side of the sedimentation tank 16. The upstream side of the liquid separation device 13 is disposed to temporarily store from the sedimentation tank 16 as The treated water storage tank 17 for which the treated water W1 discharged from the supernatant liquid is used. In the present embodiment, the treated water storage tank 17 is referred to as an additional treated water storage tank 17 in order to distinguish it from the treated water storage tank constituted by the pH adjusting tank 14 and the reaction tank 15.

Further, the additional treated water storage tank 17 may be omitted. However, as described below, by supplying the additional treated water storage tank 17, the treated water is supplied to the solid-liquid separation device 13 directly from the sedimentation tank 16. At W1, it is easy to control the supply amount of the treated water W1.

Further, on the downstream side of the solid-liquid separation device 13, a treated water storage tank 18 for storing the treated water W2 obtained by the solid-liquid separating device 13 and a filter for storing the washed solid-liquid separating device 13 are disposed. The filter auxiliary material obtained by 131 is stored and the filter auxiliary material and the washing water storage tank 19 used for the washing water washed by the filter 131 are stored.

Further, the treated water storage tank 18 may be omitted. However, as shown in the following description, by providing the treated water storage tank 18, the control of the washing water supplied to the solid-liquid separation device 13 is easily performed, and even if solid-liquid separation is performed When the device 13 is suddenly broken, the supply of the above-described washing water can be stably performed.

Further, on the downstream side of the sedimentation tank 16, a concentration tank 21 for transferring a calcium fluoride slurry obtained in a predetermined amount of the sedimentation tank 16 and concentrating the slurry is disposed; and being concentrated on the downstream side of the concentration tank 21 to carry out concentration A dewatering machine 22 for drying the slurry concentrated in the tank 21.

The filter auxiliary material storage tank 11 and the filter auxiliary material metering tank 12 are connected by a pipe 31, and a pump is provided on the pipe 31. 51. The filtration auxiliary material metering tank 12 and the solid-liquid separation device 13 are connected by pipes 32 and 33, and a pump 52 is disposed on the pipe 32. The solid-liquid separation device 13 and the treated water storage tank 18 are connected by a pipe 38. The treated water storage tank 18, the filtering auxiliary material and the washing water storage tank 19 are connected by a pipe 39, and a pump 54 is disposed on the pipe 39. Further, the solid-liquid separation device 13 and the filter auxiliary material and the washing water storage tank 19 are connected by a pipe 41.

The pH adjusting tank 14 and the reaction tank 15 are connected by a pipe 34. The reaction tank 15 and the precipitation tank 16 are connected by a pipe 35. The sedimentation tank 16 and the additional treated water storage tank 17 are connected by a pipe 36, and the treated water storage tank 17 and the solid-liquid separation device 13 are added, and the pipes 37 and 33 are connected, and the pump 37 is provided with a pump 53. .

The reaction tank 15 and the filter auxiliary material and the washing water storage tank 19 are connected by a pipe 42, and the pump 55 and the three-way valve 63 are disposed on the pipe 42, and the pipe 44 is branched from the pipe 42 and flows through The flow filtering auxiliary material in the pipe 42 is transferred and stored in the filtering auxiliary material storage tank 11 via the pipe 44. Further, in the present embodiment, the pipe 42 constitutes the first return line.

The sedimentation tank 16 and the reaction tank 15 are connected by pipings 45 and 46, and a pump 56 is disposed on the piping 45. Further, in the present embodiment, the pipes 45 and 46 constitute a second return line. Further, the precipitation tank 16 and the concentration tank 21 are connected by a pipe 47, and the concentration tank 21 and the dewatering machine 22 are connected by a pipe 48, and a pump 57 is disposed on the pipe 48.

Mixers 141, 151, and 161 are disposed in the pH adjusting tank 14, the reaction tank 15, and the sedimentation tank 16, respectively. Further, a magnetic separating device 191 is disposed in the filtering auxiliary material and the washing water storage tank 19, and a permanent magnet or an electromagnet (not shown) is housed in the magnetic separating device 191.

Next, a description will be given of a water treatment method using the water treatment device 10 shown in Fig. 1 . First, a specific amount of the filter auxiliary slurry is transferred from the filter auxiliary material storage tank 11 to the filter auxiliary metering tank 12 via the piping 31 by driving the pump 31. Next, the pump 52 is driven to open the filter 61 to supply the filter auxiliary slurry to the filter 131 of the solid-liquid separation device 13 from the filter auxiliary metering tank 12 via the pipe 32, and filter is formed on the filter 131. The film of the auxiliary material forms a so-called pre-coating layer 132. Further, the thickness of the precoat layer 132 is not particularly limited as long as the float in the water to be treated W1 can be removed as shown in the following description, and may be, for example, 0.1 mm to 10 mm.

Next, the treated water W1 is introduced into the pH adjusting tank 14 while the pH adjusting agent is added, and it is preferable to set the pH of the water to be treated W1 in the pH adjusting tank 14 to a range of 2 to 4. Thereby, the conversion of fluoride ions in the reaction tank 15 into calcium fluoride can be promoted. Further, at this time, stirring is performed by the agitator 141 to uniformly mix the pH adjuster in the water W to be treated.

The pH adjuster may be, for example, sulfuric acid, nitric acid, an organic acid, or a hydrogen halide other than hydrogen fluoride. Among them, sulfuric acid is the best. Sulfuric acid, which becomes a sulfate ion in the water W1 to be treated, reacts with calcium ions of a calcium-containing inorganic substance to become calcium sulfate having a small solubility, and the excess ions are solidified. Chemical.

Next, the pH-controlled water to be treated W1 is transferred from the pH adjusting tank 14 to the reaction tank 15 through the piping 34, and in the reaction tank 15, a water-insoluble calcium-containing inorganic substance is added to the pH-treated water W1 to be treated. In the reaction tank 11, fluoride ions contained in the water W1 to be treated are converted into calcium fluoride. At this time, the agitator 151 is sufficiently stirred to disperse the calcium-containing inorganic substance in the water W1 to be treated in the reaction tank 15.

In the present embodiment, the "water-insoluble calcium-containing inorganic substance" means a calcium-containing inorganic substance having a solubility in water of 10 g or less (25 ° C) per 1000 ml.

Further, the calcium-containing inorganic substance is preferably a substance having no hydrate and a hydroxyl group. A substance having a hydrate and a hydroxyl group has a soft characteristic compared with other substances, and sometimes blocks the pores of the filter.

Specifically, for example, it may be aragonite, sodium borate, aragonite, omphacite, calcium chrome garnet, scheelite, perovskite, calcite, zoisite, fisheye, dolomite, Aluminum fluorogypsum, red curtain stone, ash travertine, dihydrate gypsum, vermiculite, mentholite, anorthite, diopside, mafic pyroxene, manganese feldspar, tremolite, rose phosgene, variegated pyroxene, Natural ore of amphibole, pyroxene, amphibole, fushan stone, Yijian stone, calcite, vermiculite, montmorillonite, actinolite, epidote, oblique scutellite, apatite. Further, for example, a calcium compound obtained by a synthesis and a production process such as calcium carbonate, calcium sulfite, calcium hydroxide, calcium sulfate, calcium titanate or calcium tungstate may be used.

Among the above, the solubility of water is small. Calcium and calcium carbonate are the main components of the ore (for example, aragonite, dolomite), and in particular, calcium carbonate which does not cause an anion other than the fluoride ion to be removed is preferable.

As the calcium-containing inorganic substance as described above, it is preferred to use particles having an average particle diameter of 2 to 50 μm. When the average particle diameter exceeds 50 μm, the surface area of the calcium-containing inorganic material becomes small, and the reaction rate when the fluorine ion is converted into calcium fluoride may be delayed. When the average particle diameter is less than 2 μm, the diameter of the produced calcium fluoride is small, and it may be difficult to collect the solid-liquid separation tank 13 described below.

The calcium-containing inorganic substance having an average particle diameter as described above is obtained by appropriate classification. When the particle diameter of the calcium-containing inorganic material obtained is larger than the average particle diameter, the powder is pulverized by a ball mill, a Henschel mixer, a roller or the like.

Next, the water to be treated W1 containing the produced calcium fluoride is transferred from the reaction tank 15 to the precipitation tank 16 via the piping 35, and is stored in the additional treated water storage tank 17 via the piping 36, and the pump is driven by the pump. 53. The pre-coating layer 132 supplied to the solid-liquid separation device 13 via the pipes 37 and 33 is passed through the pre-coating layer 132 to remove calcium fluoride in the water to be treated W1.

When the treated water W1 is supplied to the solid-liquid separation device 13 from the additional treated water storage tank 17, the valve 61 is closed and the valve 62 is opened, so that the water to be treated W1 does not flow back to the filtering auxiliary material measuring tank 12.

After the water to be treated W1 is passed through the pre-coating layer 132, it is treated as the treated water W2, and is transferred from the solid-liquid separating device 13 via the piping 38. Up to the treated water storage tank 18. Next, the pump 54 is driven to transfer the part of the treated water W2 from the treated water storage tank 18 to the filtering aid and the washing water storage tank 19 via the piping 39, and drives the pump 55 to supply the piping through the pipes 42, 43 and 33. The pre-coating layer 132 in the solid-liquid separating device 13 breaks the pre-coating layer 132, and supplies the filtering auxiliary material constituting the pre-coating layer 132 to the filtering auxiliary material and the washing water storage tank 19 via the piping 41. At this time, the solid-liquid separating device 13 side of the three-way valve 63 is opened, and the reaction tank 15 side is closed.

At this time, in the filter auxiliary material and the washing water storage tank 19, there are a filter auxiliary material and a pre-coating layer 132, that is, fine calcium fluoride and washing water adhering to the filter auxiliary material.

Next, by driving the magnetic separation device 191 disposed in the filtering auxiliary material and the washing water storage tank 19, only the filtering auxiliary material is adsorbed to the magnetic separating device 191, and the pump 55 is used to contain the fine calcium fluoride. The washing water, that is, the aqueous solution in which the fine calcium fluoride is dispersed, is returned to the reaction tank 15 through the pipe 42. At this time, the solid-liquid separating device 13 side of the three-way valve 63 is closed, and the reaction tank 15 side is opened.

Next, the operation of the magnetic separator 191 is released, and the filter auxiliary material is transferred to the filter auxiliary material storage tank 11 via the pipes 42 and 44 (the valve 64 is opened) by driving the pump 55.

Next, as described above, by driving the pump 51, a certain amount of the filtering auxiliary material slurry is transferred from the filtering auxiliary material storage tank 11 to the filtering auxiliary material measuring tank 12 via the piping 31, and the pump 52 is driven by The valve 61 is opened, and the slurry of the filtering auxiliary material is supplied to the filter 131 of the solid-liquid separating device 13 from the filtering auxiliary material metering tank 12 via the pipe 32. A pre-coating layer 132 is formed on the filter 131 again.

Next, when a calcium-containing inorganic substance is added to the water W1 to be treated in the reaction tank 15, and the fluoride ion in the water W1 to be treated is again converted into calcium fluoride, the calcium fluoride is dispersed and previously washed from the auxiliary filter material. The water storage tank 19 is fed back to the calcium fluoride in the aqueous solution in the reaction tank 15, or the calcium fluoride is used as a seed core to crystallize the calcium fluoride to form the fluorine present in the treated water W1. The size of calcium is increased.

Then, the water to be treated W1 containing the enlarged calcium fluoride is introduced into the sedimentation tank 16 through the piping 35, and then transferred to the additional treated water storage tank 17 via the piping 36, and supplied to the pre-charge by the drive pump 53. On the cladding layer 132, calcium fluoride in the treated water W1 is removed from the precoat layer 132.

Thereafter, the treated water W2 obtained by passing the water of the treated water W1 to the pre-coating layer 132 is transferred from the treated water storage tank 18 to the filtering auxiliary material and the washing water storage tank 19 via the piping 39. As described above, the pre-coating layer 132 in the solid-liquid separating device 13 is supplied to break the pre-coating layer 132, and the filtering auxiliary material constituting the pre-coating layer 132 and the fine calcium fluoride adhered to the filtering auxiliary material. The washing water is introduced into the filter auxiliary material and the washing water storage tank 19 together. Then, the aqueous solution in which the fine calcium fluoride is dispersed in this manner is returned to the reaction tank 15 through the piping 42 of the first transfer line, and the calcium-containing inorganic substance is again added to the treated water W1 in the reaction tank 15. The fluoride ion in the treated water W1 is again converted into calcium fluoride, and as described above, the size of the calcium fluoride present in the treated water W1 is increased.

When a plurality of such operations are performed, for example, coarsened calcium fluoride having an average particle diameter of 20 μm or more is present in the water to be treated W1, and the water to be treated W1 is introduced into the sedimentation tank 16 through the pipe 35 from the reaction tank 15. At this time, the calcium fluoride settles at the bottom of the precipitation tank 16. On the other hand, the water to be treated W1 containing the fine calcium fluoride which has not settled in the precipitation tank 16 is used as the supernatant liquid in the sedimentation tank 16, and is sent to the solid-liquid via the additional treated water storage tank 17 in the same manner as described above. The separation device 13 is used for the above operations.

In addition, the agitator 161 disposed in the precipitating tank 16 has a function of promoting the reaction between the fluoride ions remaining in the water to be treated W1 introduced into the precipitating tank 16 and the calcium-containing inorganic substance, and promoting the formation of calcium fluoride.

Therefore, by repeating the above operation, coarsened calcium fluoride is gradually formed in the water W1 to be treated in the reaction tank 15, and coarsening is performed each time the water W1 to be treated is transferred from the reaction tank 15 to the sedimentation tank 16 Calcium fluoride is precipitated at the bottom of the precipitation tank 16, and the amount of calcium fluoride precipitated in the precipitation tank 16 is increased.

Further, in the precipitation tank 16, after a certain amount of calcium fluoride is precipitated, or when a certain amount of calcium fluoride is being precipitated, the pump 56 is driven to pass through the piping 46 of the second return line (the valve 66 is opened). The sludge containing the calcium fluoride is introduced into the reaction tank 15, and the calcium fluoride newly formed in the reaction tank 15 is combined with the calcium fluoride in the sludge, or the core is grown, and the sludge can be used. The concentration of calcium fluoride is increased.

The calcium fluoride-containing sludge precipitated at the bottom of the sedimentation tank 16 is introduced into the liquid by means of a pump 47 (valve 67 is opened) by driving the pump 45. In the tank 21, it is kept in the concentration tank 21 for several days to increase the sludge concentration. Then, the sludge is transferred from the concentration tank 21 to the dehydrator 22 via the pipe 48 by the pump 48, and the dehydration is performed, for example, to a concentration of 80% by weight of the calcium fluoride in the sludge.

In the present embodiment, the calcium-containing inorganic material is added to the water to be treated W1 containing fluorine ions, and then the operation by the pre-coating method of the solid-liquid separation device 13 is performed, and the processing can be easily and efficiently performed as long as it is performed plural times. Water W1 removes and recovers fluoride ions. That is, the fluoride ion can be removed and recovered at low cost and efficiently from waste water containing fluoride ions or the like.

[Examples]

The test was carried out using the water treatment device 10 shown in Fig. 1. The wastewater containing the fluoride ion of about 3000 mg/L is supplied as the treated water W1 to the pH adjusting tank, and after adjusting the pH to 3 with sulfuric acid, the average particle diameter is 4.0 μm with respect to the fluoride ion at a ratio of 2 times the molar ratio. The calcium carbonate powder was mixed by a stirrer 151 for 10 minutes. On the other hand, ferrite iron particles (fertilizer iron particles A) having an average particle diameter of 20 μm and ferrite iron particles (fertilizer iron particles B) having an average particle diameter of 40 μm were prepared as filter aids.

Next, the operation described in the "embodiment" is performed, and a pre-coating layer 132 having a thickness of 1 mm is formed on the filter 131 in the solid-liquid separation device 13, and the water of the simulated raw water is executed.

As a result, after repeating the above operation 5 times, it was taken out from the dehydrator. The concentration of calcium fluoride contained in the sludge was confirmed to be about 85 wt% of the ferrite iron particles A and about 89 wt% of the ferrite iron particles B.

In addition, the sludge is returned from the sedimentation tank to the sludge in the reaction tank to form a calcium fluoride precipitate at the bottom of the sedimentation tank, that is, when the sludge is formed, the concentration tank is retained for 2 days, and the dehydration time of the dehydrator is 3 hour.

The embodiments of the present invention have been described above, but the embodiments are merely illustrative and are not intended to limit the scope of the invention. The present invention can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. The invention and its modifications are intended to be included within the scope and spirit of the inventions.

10‧‧‧Water treatment unit

11‧‧‧Filter auxiliary storage tank

12‧‧‧Filter auxiliary material metering tank

13‧‧‧Solid-liquid separation device

13A‧‧‧Upper

13B‧‧‧ lower

14‧‧‧pH adjustment tank

15‧‧‧Reaction tank

16‧‧‧Sedimentation tank

17‧‧‧Additional treated water conditioning tank

18‧‧‧Processing water storage tank

19‧‧‧Filter auxiliary material and washing water storage tank

21‧‧‧concentration tank

22‧‧‧Dehydrator

31~39, 41~48‧‧‧ piping

51~57‧‧‧ pump

61‧‧‧ valve

62‧‧‧ valve

63‧‧‧Three-way valve

64‧‧‧ valve

65‧‧‧ valve

66‧‧‧Valves

67‧‧‧Valves

131‧‧‧Filter

132‧‧‧Pre-coating

141‧‧‧Mixer

151‧‧‧Mixer

161‧‧‧Mixer

191‧‧‧Magnetic separation device

W1‧‧‧ treated water

W2‧‧‧ treated water

Claims (13)

A water treatment device characterized by: a filter auxiliary material storage tank for storing a slurry containing a filter auxiliary material; and a filter auxiliary material metering tank located at a downstream side of the filter auxiliary material storage tank for measuring a specific amount The slurry supplied from the filtering auxiliary material storage tank; the solid-liquid separating device is located on the downstream side of the filtering auxiliary material metering tank, and has a filter for dividing the internal space into upper and lower sides, and the aforementioned filtering auxiliary material metering groove The slurry is supplied to the filter to form a pre-coating layer composed of the filtering auxiliary material on the filter; the treated water storage tank is located on the upstream side of the solid-liquid separating device for storing calcium fluoride. The treated water, the treated water containing calcium fluoride is passed through water to the filter forming the pre-coating layer; the filtering auxiliary material and the washing water storage tank are located on the downstream side of the solid-liquid separating device for The upper portion of the filter of the solid-liquid separation device supplies washing water, and stores the filter auxiliary material obtained by breaking the pre-coating layer and the foregoing a first return line for returning the aforementioned washing water to the treated water storage tank from the filtering auxiliary material and the washing water storage tank; the sedimentation tank is located in the treated water storage tank and the solid liquid Between the separation devices for precipitating and separating the calcium fluoride contained in the water to be treated; and a second return line for storing the water to be treated from the sedimentation tank The storage tank carries out the return of the slurry containing the calcium fluoride obtained in the sedimentation tank; the concentration tank is located on the downstream side of the sedimentation tank, and the slurry containing the calcium fluoride obtained in the sedimentation tank is concentrated; and the dehydrator Located on the downstream side of the concentration tank for drying the slurry concentrated by the concentration tank. The water treatment device according to claim 1, wherein the separation means separates the filter auxiliary material and the washing water stored in the filter auxiliary material and the washing water storage tank, The filtering auxiliary material separated by the separating means is returned to the filtering auxiliary material storage tank. The water treatment device according to the first or second aspect of the invention, wherein the sedimentation tank and the solid-liquid separation device have additional treated water for storing the water to be treated discharged from the sedimentation tank. Storage tank. The water treatment device according to the first or second aspect of the invention, wherein the downstream side of the solid-liquid separation device has a treatment water storage tank for storing the aforementioned filter for forming the pre-coating layer The treated water obtained by passing the water to be treated may supply the treated water to the filtering auxiliary material and the washing water storage tank as the washing water from the treated water storage tank. For example, the water treatment device described in claim 1 or 2, The treated water storage tank includes: a reaction tank for adding a water-insoluble calcium-containing inorganic substance to the treated water to convert fluoride ions in the treated water into calcium fluoride; and being located on the upstream side of the reaction tank A pH adjusting tank in which a pH adjuster is added to the water to be treated for the purpose of promoting the aforementioned conversion. The water treatment device according to claim 1 or 2, wherein the solid-liquid separation device is a horizontal filter. A water treatment method characterized by comprising: a first step for transferring a slurry containing a filter auxiliary material from a filter auxiliary material storage tank to a filter auxiliary material metering tank located on a downstream side of the filter auxiliary material storage tank to measure a specific amount of the mud; the second step, by separating a specific amount of the slurry from the filtering auxiliary material metering tank to the downstream side of the filtering auxiliary material metering tank, and dividing the internal space into upper and lower solid-liquid separation by the filter a device for forming a pre-coating layer composed of the filtering auxiliary material on the filter; and a third step for treating the water to be treated containing calcium fluoride from the water to be treated located on the upstream side of the solid-liquid separating device a storage tank supplied with water to the filter formed with the pre-coating layer, wherein the calcium fluoride is adsorbed and removed in the pre-coating layer; and a fourth step for supplying the washing water to the solid-liquid separating device The filter upper portion is provided, and the filter auxiliary material obtained by breaking the pre-coating layer is stored in the filter auxiliary material together with the washing water. a water storage tank; in the fifth step, the washing water is returned from the filtering auxiliary material and the washing water storage tank to the treated water storage tank through the first return line; and the sixth step is located in the treated water a sedimentation tank between the storage tank and the solid-liquid separation device, and sedimentation separation of the calcium fluoride contained in the water to be treated mixed with the washing water returned by the first return line; And the slurry containing the calcium fluoride obtained in the precipitation tank is returned from the sedimentation tank to the treated water storage tank through the second return line; and the eighth step is concentrated on the downstream side of the sedimentation tank. In the tank, the slurry containing the calcium fluoride obtained in the sedimentation tank is concentrated; and in the ninth step, the concentrated slurry is dried in a dewatering machine located on the downstream side of the concentration tank. The water treatment method according to claim 7, wherein in the fifth step, the filtering auxiliary material and the washing water stored in the filtering auxiliary material and the washing water storage tank are separated, and then the The separated filter auxiliary material is returned to the filter auxiliary material storage tank via the first return line. The water treatment method according to claim 8, wherein the first to sixth steps are repeatedly performed on the water to be treated discharged from the sedimentation tank. The water treatment method as described in claim 7 of the patent application, In the third step, the additional treated water storage tank disposed between the precipitation tank and the solid-liquid separation device temporarily stores the treated water discharged from the sedimentation tank, and then separates the solid-liquid separation The device supplies the treated water. The water treatment method according to any one of claims 7 to 10, wherein in the fourth step, the filter having the pre-coating layer is subjected to water passage of the water to be treated. The treated water is stored in a treated water storage tank disposed on the downstream side of the solid-liquid separation device, and the treated water is used as the washing water. The water treatment method according to any one of claims 7 to 10, wherein before the third step, a Ph adjuster is added to the water to be treated, followed by adding a calcium-insoluble inorganic substance insoluble in water, The fluoride ions in the treated water are converted into calcium fluoride. The water treatment method according to any one of claims 7 to 10, wherein the solid-liquid separation device is a horizontal filter.