JP2008086852A - Water treating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply daily life water by removing a dissolved organic substance from natural water with a method unnecessary for a consumption member and to supply the removed organic substance as a surfactant by recovering the removed organic substance with labor hour-saving method. <P>SOLUTION: When a water treating device operated by a mode of supplying purified water, in an acidification tank 2, the pH of the natural water is reduced to protonate an acid functional group of the dissolved organic substance to increase hydrophobicity and in an adsorption tank 6, the dissolved organic substance is reversibly adsorbed to a hydrophobic resin having a macro network structure to remove it. When operated by a mode of recovering the organic substance, an alkaline liquid is introduced into the adsorption tank 6 to desorb the organic substance. At this time, a cation exchange resin contained in the acidification tank 2 is regenerated to a proton type and the hydrophobic resin in the adsorption tank 6 is also regenerated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a water treatment apparatus that removes organic substances contained in natural water such as lakes, rivers, and groundwater, water and sewage systems, and domestic wastewater, and that can effectively use the removed organic substances. It is.

  Wetlands, lakesides, riverside zones, etc. dissolve organic matter in natural water from the rich plant deposits such as peat. Water with an organic carbon concentration exceeding 5 ppm does not meet the standards of tap water, and when the organic carbon concentration exceeds approximately 10 ppm, it is colored yellow-brown, so the use as water for domestic use is limited by fouling bright fibers, etc. . Therefore, in order to use natural water rich in organic matter for domestic use, organic matter removal treatment such as filtration using activated carbon or semipermeable membrane, or decomposition of organic matter by microbial or chemical treatment is required. is necessary.

  While there is a need to remove organic matter from natural water, there is also a need to make effective use of organic matter. Most of organic substances dissolved in natural water are humic substances such as fulvic acid and humic acid. The humic substance is an end product of an amorphous polymer in which plants and the like are decomposed by microorganisms. Typical chemical structures of fulvic acid and humic acid have an aromatic ring with an aliphatic side chain, a skeleton structure rich in double bonds, and acidic functional groups such as carboxyl groups and hydroxyl groups (non- Patent Document 1). That is, it is an amphiphilic substance having a hydrophobic skeleton structure and a hydrophilic functional group in one molecule, and has a surface active action. Therefore, it is used as a raw material for body soaps and shampoos consisting only of natural chemical components (see, for example, Patent Document 1). Other than that, humic substances have the effect of weakening the toxicity of heavy metal ions by chelating, removing rust on the metal surface, and promoting the growth of plants, and are used in the agricultural, water treatment, and general industrial fields. There are a variety of methods.

In addition, a semipermeable membrane for removing organic substances from natural water is likely to be clogged although it is expensive. In addition, activated carbon has a large adsorption capacity for organic substances, but there are problems that microorganisms are easy to propagate on its surface and that it takes time and effort to replace it periodically. Therefore, a treatment method (for example, see Patent Document 2) in which a photocatalyst is supported on activated carbon and decomposed by UV light has been developed.
Japanese Patent No. 357347 JP 2000-202468 A Journal of Chromatography A, vol. 983, 1-2, p. 1-18

  However, even in the treatment method disclosed in Patent Document 2, it is difficult to completely decompose high molecular organic substances such as humic substances generated from peat and the like, and periodic replacement of the activated carbon cartridge is inevitable.

  Wetlands such as wetlands, lakesides, and riversides are being landfilled and shrinking, despite being an important environment for plant and bird ecology. In the case of typical marshlands such as Kushiro Marsh and Oze, many people visit for sightseeing and recreational purposes, and appropriate management is required so as not to place excessive loads such as artificial pollutants on the marsh. In 2005, the number of Japanese wetlands registered in the Ramsar Convention, which establishes the conservation of wetlands, nearly tripled, so that it can be used for tourism and recreation while properly maintaining and managing the areas adjacent to the wetlands. desirable. From such a point of view, it is difficult to create a facility that chemically oxidizes and decomposes dissolved organic matter in the vicinity of wetlands.

  On the other hand, in order to prepare a humic substance solution, 1. Collect raw materials such as peat, litter, humus and soil. 2. Extract from raw materials. It is necessary to purify by removing impurities. Collecting raw materials from wetlands and satoyama can cause excessive disturbance to the ecosystem. Extraction from raw materials takes equipment, labor and time. In the refining process, filtration equipment and heating equipment are necessary to remove a large amount of microbes derived from fine particles and raw materials, which is expensive. Furthermore, since the extracted humic substances are normally distributed in a liquid state, the distribution cost is high and the storage cost for refrigeration is high. The reason that humic substances are rarely used commercially even though they are useful materials of natural origin is largely due to the reasons described above.

  The present invention solves the above-mentioned conventional problems, removes organic matter from water in which a large amount of organic matter is dissolved by a method that does not require a consumable member, supplies water for daily use, and concentrates the removed organic matter in a laborious manner. The purpose is to collect and use.

  In order to solve the conventional problems, the water treatment apparatus of the present invention includes raw water supply means for supplying raw water, pH lowering means for lowering the pH of water supplied from the raw water supply means, and pH lowering means. An adsorption tank for adsorbing organic substances contained in water whose pH has been lowered by the pH, and a pH raising means for controlling the desorption of the organic substances adsorbed in the adsorption tank, wherein the adsorption tank has a coarse mesh structure adsorbent It is characterized by having. That is, the adsorption and desorption of organic substances is controlled in an adsorption tank in which the pH lowering means and the pH raising means can reversibly absorb and desorb organic substances. By using an adsorbent with a coarse network structure, even humic substances, which are high molecular substances with a molecular weight exceeding 100,000 daltons, can be held between the network structures in a detachable state. (Ie it can be reversible). Further, by changing the pH, the degree of dissociation of the acidic functional group of the humic substance is changed to change the hydrophilicity of the molecule, and as a result, the adsorption / desorption can be controlled by controlling the affinity for the adsorbent. In addition, organic substances can be removed from natural water without using a disposable adsorption cartridge or a semipermeable membrane, and humic substances can be concentrated and collected without trouble. If the recovered humic substance solution is used as a surfactant for cleaning, the aquatic environment is not loaded with substances from the outside unlike ordinary detergents.

  The water treatment apparatus of the present invention can realize the water treatment apparatus with good maintainability by controlling the adsorption and desorption of organic substances contained in the water.

  1st invention adsorb | sucks the organic substance contained in the water by which the raw material water supply means which supplies raw | natural water, the pH reduction means to reduce the pH of the water supplied from the said raw water supply means, and the pH reduction means by the said pH reduction means And a pH raising means for controlling the desorption of the organic matter adsorbed in the adsorption tank, and the adsorption tank has an adsorbent having a coarse mesh structure.

  Then, by lowering the pH of the raw water, the acidic functional group of the humic substance can be protonated to increase the hydrophobicity, and can be adsorbed on the hydrophobic adsorbent. Further, by supplying a solution having a high pH to the adsorption tank, the acidic functional group of the humic substance is dissociated to be hydrophilized and desorbed from the hydrophobic adsorbent. Thus, the adsorption / desorption of organic substances can be controlled by changing the pH.

2nd invention is the water treatment apparatus which incorporated hydrophobic macroporous resin in the adsorption tank. By using an adsorbent with a coarse network structure, even humic macromolecules with molecular weights exceeding 100,000 daltons can be adsorbed and retained between the networks in a detachable state. As a result, when the adsorbent is saturated with organic matter, it can be desorbed and regenerated.

  A third invention is a water treatment apparatus in which the pH lowering means and the pH increasing means are constituted by at least one pair of electrodes and voltage applying means. Natural water generally contains about 1 to 10 mM of dissolved minerals. When this mineral is used as an electrolysis auxiliary agent, acid and alkali for controlling adsorption / desorption can be generated without consuming materials other than electric energy. As a result, labor for supplying materials such as acid and alkali becomes unnecessary.

  According to a fourth aspect of the present invention, the pH lowering means and the pH increasing means have an acidification tank containing a proton type cation exchange resin, and a regeneration tank adjacent to both sides of the acidification tank and the semipermeable membrane. In addition, the regeneration tank is provided with a pair of electrodes.

  Wetland water and groundwater may contain divalent iron ions at a concentration of several to several tens of ppm, and when introduced into the device as they are, they become insoluble trivalent iron ions around oxidative environmental components such as the anode, and a large amount of water. Oxide precipitates (red rust) and clogs the flow path. Moreover, even when it does not contain divalent iron ions, it is expected that a scale is formed around the parts where the polyvalent cations have a high pH. In order to eliminate such a risk, the raw water first passes through a proton-type cation exchange tank, and all the cations are adsorbed by the ion exchange resin. In addition, the pH of the raw water is lowered to about 3 by this operation. With very few exceptions such as oxalic acid, the pKa value of the carboxyl group of the organic acid is 3 or more, and the average pKa value of humic substances is between 4.5 and 5.0. Therefore, most of the humic substances are adsorbed because they are almost completely protonated at pH 3. The cation exchange resin is regenerated to the proton type by electrolysis of water.

  According to a fifth aspect of the present invention, an opening is provided on a side surface of the adsorption tank so that the color of the adsorbent in the adsorption tank is visible from outside the adsorption tank. Since it can be confirmed that the adsorption capacity of the adsorbent has decreased below a certain level from the opening, the adsorbent can be regenerated by operating in a mode in which organic matter is desorbed when the capacity to regenerate the adsorbent is visible. To process.

  The sixth invention is provided with a detecting means for detecting a change in the color of the adsorbent, and a control means for operating the pH increasing means in conjunction with the detecting means. Thereby, the remaining amount of the adsorption capacity of the adsorbent is automatically detected by detecting the color change. If it can be confirmed that the adsorption capacity has decreased to a certain level or less, the adsorbent can be regenerated by automatically switching to the desorption mode and operating.

  7th invention is equipped with the organic substance supply tank which supplies a vegetable organic substance in the middle of the flow path of a raw | natural water supply means. The water obtained from the marsh shows fluctuations in the concentration of organic matter depending on the season and weather. Therefore, depending on the time, a sufficient amount of the humic solution for washing may not be recovered. In such a case, the plant organic matter is stored in the middle of the flow path for supplying the raw water or upstream of the branched flow path so that the plant organic matter is immersed in water for the purpose of adding the dissolved organic matter. A stable amount of the humic substance solution can be supplied regardless of the time based on the dissolved organic matter added in this way. In addition, depending on the plant organic matter to be added, it is possible to impart a scent that suits the user's preference to the recovered organic matter.

(Embodiment 1)
FIG. 1 is a schematic diagram of a water treatment apparatus according to the first embodiment of the present invention.

In FIG. 1, the upstream end of the raw water supply means 1 is immersed in water such as a river, a lake, a well, and a basin flowing from a wetland. The raw water supplied from this is a pH lowering means and an acidification tank 2 which is a pH raising means, a regeneration tank 2a adjacent to the acidification tank 2 through the semipermeable membrane 4,
It passes through 2b, passes through the valve 10a, is supplied to the adsorption tank 6, is drained by connection of the valve 10b, and is supplied to piping so that it can be used as domestic water. If necessary, the valve 10a adjusts the connection so that the flow path of the water supplied from the regeneration tank 2 is connected to the reservoir 11 that stores the dissolved organic matter, and the dissolved organic matter that has been removed is stored in the valve 10c. This is a configuration that can be discharged and used.

  A partial opening 7 is provided on the side surface of the adsorption tank 6 so that the state of the adsorbent in the adsorption tank 6 can be visually recognized from the outside. The control means 9 controls the voltage application means 5 for applying a voltage to the electrodes provided in the regeneration tanks 2a and 2b, and controls the detection means 8 for detecting the state of the adsorbent in the adsorption tank 6 by color.

  The raw water introduced from the raw water supply pipe 1 is acidified to about pH 3 by passing through an acidification tank 2 filled with a proton type cation exchange resin. Below pH 3, most of the carboxyl groups and hydroxyl groups of the dissolved organic matter are protonated and lose their negative charge, so they become hydrophobic.

  Normally, the valve 10 a is opened so as to connect the acidification tank 2 and the adsorption tank 6, and the dissolved organic matter that has been protonated and hydrophobized is introduced into the adsorption tank 6. The valve 10b is opened downward at that time, and the water that has passed through the adsorption tank 6 is drained, and can be used as water for general living such as washing, bathing, toilet water, and car washing. The adsorption tank 6 is filled with a hydrophobic resin DAX-8 (SPELCO) or XAD resin (ROHM & HAAS), and adsorbs proton-type dissolved organic substances by hydrophobic interaction. Since these hydrophobic resins have moderate hydrophobicity and a huge network structure, they have a feature of reversibly adsorbing and desorbing dissolved organic substances. Therefore, the adsorption tank can be regenerated by dissociating the carboxyl group of the adsorbed organic substance under an alkaline condition to make it hydrophilic. Therefore, it is not necessary to replace the adsorbent and the running cost can be suppressed. In addition, by providing an automatic regeneration mechanism as described below, it is possible to automatically regenerate the adsorption tank before it is saturated with organic matter, thereby greatly reducing the maintenance effort.

The cation exchange resin partially neutralized by receiving cations from the raw water in the acidification tank 2 is intermittently regenerated by the electrode 3 and the voltage application means 5 to become a proton type. By applying a DC voltage of about 3 V or more, water molecules in the acidification tank 2 are dissociated into H ⁺ and OH ⁻ by the following chemical reaction (1) (1), and a part of H ⁺ is caused by a cation exchange resin. Replaces retained mineral cations.
H ₂ O → H ⁺ + OH ⁻ (1)
Cations and H ⁺ are attracted toward the cathode 3b, pass through the semipermeable membrane 4 and move to the vicinity of the electrode. At that time, the following oxidation reaction (2) occurs on the anode 3a side, and the reduction reaction (3) occurs on the cathode 3b side.
2OH ⁻ → H ₂ O + 1 / 2O ₂ + 2e ⁻ (2)
2H ₂ O + 2e ⁻ → H ₂ + 2OH ⁻ (3)
When the acidification tank 2 is regenerated, the adsorption tank 6 is also regenerated. The bubble 10b is opened so as to connect the tank on the cathode 3b side and the adsorption tank, and the alkaline liquid obtained on the cathode 3b side is introduced into the adsorption tank 6 in the direction opposite to that during normal use. At that time, the bubble 10 a is opened so that the desorbed dissolved organic matter flows into the reservoir 11. When necessary, the valve 10c can be opened to use the dissolved organic matter stored in the reservoir. Utilizing the surface active action of dissolved organic matter, it can be used in detergent applications. In addition, the dissolved organic matter immediately after desorption has a low oxidation-reduction potential using the alkaline electrolyzed water obtained at the cathode 3b as a solvent, so that it does not rust the metal and is suitable for washing objects to be cleaned including metal parts such as farm equipment. Yes.

A transparent pressure-resistant glass plate is fitted in the opening 7 of the adsorption tank, and the color of the adsorbent can be distinguished from the outside. Organic substances that are highly hydrophobic and easily adsorbed are generally humic substances, and their chemical structure is rich in double bonds, and thus exhibits a brown color. Since the adsorbent itself is white, the saturated portion of the adsorbent becomes brown and can be distinguished in color. In order to sufficiently remove organic substances from the raw water, the adsorbent should be regenerated when 1/3 is saturated from the inlet of the adsorbent. It is necessary to regenerate by detecting the color change of the adsorbent by the detecting means 8 for detecting the color provided outside the opening 7 and at a position 1/3 from the entrance of the adsorption tank 6 to determine the degree of saturation. When the timing is detected, the electrolysis is started by the control means 9 and the acidification tank 2 and the adsorption tank 6 are regenerated.

  Some organic substances are not sufficiently desorbed from the adsorption tank 6 even under alkaline conditions. Once every two months, the adsorption tank 6 is more completely regenerated by flowing ethanol through the flow path with the valves 10a, 10b, and 10c opened in the direction of regeneration. In this case, in order to prevent bubbles from being generated in the acidification tank 2 and the adsorption tank 6, 99% of industrial ethanol is first diluted in half, then not diluted, and finally in half. Let's flush with.

  The water treatment apparatus according to the embodiment of the present invention is a pH lowering means and a regeneration tank adjacent to both sides of the acidification tank 2 which is a pH raising means and the acidification tank 2 via a semipermeable membrane 4. 2a, 2b and adsorption tank 6 can be operated by switching between a mode for removing organic substances from raw water and a mode for collecting adsorbed organic substances for use simply by changing the connection state. It is. That is, as a result, organic substances can be removed from natural water without using a disposable adsorption cartridge or a semipermeable membrane, and the humic substances can be concentrated and collected without taking time and effort. If the recovered humic substance solution is used as a surfactant for cleaning, the aquatic environment is not loaded with substances from the outside unlike ordinary detergents.

(Embodiment 2)
FIG. 2 shows a schematic diagram of a water treatment apparatus according to the second embodiment of the present invention. However, only the upstream part of the water treatment apparatus is shown, the downstream part from FIG. 2 has the same configuration as in the first embodiment, and the same reference numerals used in the description are the same as those in the first embodiment. Illustration is omitted here.

  In FIG. 2, the upstream end of the raw water supply means 1 is immersed in water such as a river, a lake, a well, and a basin flowing from a wetland. The raw water is supplied to the branch pipe 15 by the action of the pumping pump 12. The absorbance of light having a wavelength of 260 nm is measured by a light source 17 and a photometer 18 each having a quartz cell 16 in a part of the branch pipe 15 and constituted by an ultraviolet lamp. Since the absorbance at 260 nm is proportional to the dissolved organic matter concentration, the dissolved organic matter concentration can be estimated from the absorbance. When the dissolved organic matter concentration falls below a certain value, the control unit 19 performs control such that the valve 13 opens in a direction in which the raw water passes through the organic matter supply tank 20. The wavelength measured by the photometer 18 may be other than 260 nm, and generally a wavelength of 200 nm to 300 nm is selected. The wavelength in the visible light region can be selected. In this case, the cell 16 is made of glass and the light source 17 is a tungsten lamp or the like. It is possible to always recover a sufficient amount of humic solution by filling the organic substance supply tank 20 with plant organic substances such as fallen leaves and peat. In addition, by supplying the organic matter supply tank 20 with aromatic plants such as black leaves and herbs, tea leaves after use, coffee cake, citrus peel, etc., a preferred scent is imparted to the humic solution to be recovered. Is possible. Moreover, it is possible to collect a humic substance solution to which an antibacterial component has been added by supplying terpenes-containing cypress, cypress, tsutsuga, larch xylem, shikimi leaves, and the like.

If a humic substance solution having a surface-active action is used for the primary cleaning of agricultural products in an agricultural product collection site or the like, soil particle dirt can be efficiently cleaned by a method that is safer than detergents and soaps. In addition, the treated water from which organic substances have been removed can be used for the final cleaning, and more sophisticated cleaning can be performed with one water treatment device.

The block diagram of the water treatment apparatus in Embodiment 1 The block diagram of the upstream part of the water treatment apparatus in Embodiment 2

Explanation of symbols

1 Raw water supply means 2 Acidification tank (pH lowering means, pH increasing means)
2a, 2b Regeneration tank (pH lowering means, pH increasing means)
DESCRIPTION OF SYMBOLS 3 Electrode 4 Semipermeable membrane 5 Voltage application means 6 Adsorption tank 7 Opening part 8 Detection means 9 Control means 20 Organic substance supply tank

Claims (7)

Raw water supply means for supplying raw water, pH lowering means for lowering the pH of the water supplied from the raw water supply means, and an adsorption tank for adsorbing organic substances contained in water whose pH has been lowered by the pH lowering means, And a pH raising means for controlling the desorption of the organic matter adsorbed in the adsorption tank, wherein the adsorption tank has an adsorbent having a coarse mesh structure. The water treatment apparatus according to claim 1, wherein the adsorption tank contains a hydrophobic macroporous resin. The water treatment apparatus according to claim 1 or 2, wherein the pH lowering means and the pH increasing means comprise at least one pair of electrodes and a voltage applying means. The pH lowering means is
An acidification tank containing a proton-type cation exchange resin, a regeneration tank adjacent to both sides of the acidification tank and a semipermeable membrane, and a pair of electrodes provided in the regeneration tank. The water treatment apparatus of any one of 1-3. The water treatment apparatus according to any one of claims 1 to 4, wherein an opening is provided on a side surface of the adsorption tank so that the color of the adsorbent in the adsorption tank is visible from outside the adsorption tank. The water treatment apparatus according to any one of claims 1 to 5, further comprising a detection unit that detects a change in color of the adsorbent, and includes a control unit that operates a pH increase unit in conjunction with the detection unit. The water treatment apparatus according to any one of claims 1 to 6, further comprising an organic substance supply tank for supplying plant organic substances in the middle of the flow path of the raw water supply means.

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