JP5986819B2 - Water treatment method and equipment - Google Patents

Description

  The present invention relates to a water treatment method and equipment, and more particularly to a water treatment method and equipment using an ion exchange resin.

  As a method for treating raw water having a high soluble organic component concentration, a method is known in which the soluble organic component is adsorbed on an anion exchange resin and removed from the raw water. An anion exchange resin can be reused by desorbing impurities such as adsorbed organic components by performing a regeneration treatment with a regeneration solution, usually a sodium chloride aqueous solution (saline solution). On the other hand, the regenerated liquid becomes a regenerated waste liquid containing impurities desorbed from the anion exchange resin. Since this reclaimed waste liquid contains salt and impurities, it must be treated separately from the raw water. For example, polyaluminum chloride is added to the reclaimed waste liquid to coagulate and precipitate organic matter and sulfate, and then removed from the reclaimed waste liquid. Thus, it has been proposed to reuse the recycled waste liquid as the recycled liquid (for example, see Patent Document 1).

JP 2005-296756 A

  However, since wastes composed of organic substances and precipitates containing sulfates removed from the regenerated waste liquid are generated, facilities for treating the wastes are necessary, and waste treatment facilities are installed in the water treatment facilities, It was necessary to transport the waste to a processing company.

  Accordingly, an object of the present invention is to provide a water treatment method and equipment capable of constructing a closed system without adding special equipment when performing water treatment using an ion exchange resin.

In order to achieve the above object, the water treatment method of the present invention comprises an ion exchange step of contacting raw water with an anion exchange resin to remove soluble organic components contained in the raw water, and the solubility in the ion exchange step . A coagulation-precipitation step in which a coagulant is added to the raw water from which the organic components have been removed to agglomerate suspended components contained in the raw water to precipitate and separate, and the anion adsorbing the soluble organic components in the ion-exchange step A regeneration step of regenerating the exchange resin using an aqueous sodium chloride solution, a regeneration waste solution generated by regenerating the anion exchange resin in the regeneration step, and sludge precipitated and discharged in the coagulation sedimentation step And a liquid component returning step of extracting a liquid component in the solid-liquid mixture mixed in the solid-liquid mixture separation step and mixing it with the raw water.

Furthermore, the water treatment method of the present invention, prior Symbol solid-liquid mixture separation step, mixing step and, sludge concentration step of separating and concentrating the sludge of the mixed solid-liquid mixture which is mixed with the said reproduction effluent sludge The liquid component to be mixed with raw water is extracted at the sludge concentration stage.

The water treatment facility of the present invention includes an ion exchange treatment tank that removes soluble organic components contained in the raw water by bringing the raw water into contact with an anion exchange resin, and the soluble organic component is contained in the ion exchange treatment tank. A flocculant is added to the removed raw water to agglomerate suspended components contained in the raw water to precipitate and separate, and the anion exchange resin adsorbs the soluble organic component in the ion exchange treatment tank A regenerator using a sodium chloride aqueous solution, a regenerated waste liquid generated by regenerating the anion exchange resin by the regenerator and a sludge precipitated and discharged in the coagulation sedimentation tank. A liquid mixing / separation tank and a liquid component return path for extracting the liquid component in the solid / liquid mixture mixed in the solid / liquid mixing / separation tank and mixing the liquid component with the raw water are provided .

Furthermore, the water treatment apparatus of the present invention, the pre-Symbol solid-liquid mixture separation tank, the reproduction effluent and the mixing section for mixing the sludge, the sludge concentrated portion of the sludge mixed solid-liquid mixture is separated and concentrated And the liquid component return path is preferably formed so as to mix the separated water generated in the sludge concentrating section with the raw water.

  According to the present invention, by mixing the regenerated waste liquid with the sludge containing the flocculant, the organic matter in the regenerated waste liquid can be taken into the sludge, the liquid components can be mixed with the raw water, and the organic matter etc. The sludge that has taken in can be treated in the same manner as excess sludge generated by normal water treatment. Thereby, the closed system-ization of the equipment which performs water treatment using an ion exchange resin can be aimed at.

BRIEF DESCRIPTION OF THE DRAWINGS It is a systematic diagram which shows the 1st form example of the water treatment facility which can implement the water treatment method of this invention. It is a systematic diagram which shows a reference example.

  A first embodiment of the water treatment facility shown in FIG. 1 includes a raw water tank 11, an ion exchange treatment tank 12 in which the raw water and an anion exchange resin are brought into contact, and raw water after ion exchange treatment (hereinafter referred to as ion exchange treated water). A coagulating / precipitation tank 13 for coagulating and separating the suspended components by adding a coagulant to the above), a regeneration means 14 for regenerating the anion exchange resin after contacting the raw water in the ion exchange treatment tank 12, A solid-liquid mixing / separation tank 15 for mixing the regenerated waste liquid generated in the regenerating means 14 and the sludge precipitated in the coagulating sedimentation tank 13 is provided.

  The ion exchange treatment tank 12 contacts raw water and an anion exchange resin to adsorb soluble organic components (soluble organic carbon: DOC) contained in the raw water to the anion exchange resin and removes the raw water from the raw water. An ion exchange step is performed, and in the ion exchange step, a negatively charged organic substance is converted by ion exchange between a chloride ion or a chlorine ion which is an exchange group of the anion exchange resin and a negatively charged organic substance in the raw water. It is adsorbed on the anion exchange resin and removed from the raw water.

  The agglomeration sedimentation tank 13 provided in the subsequent stage of the ion exchange treatment tank 12 is supplied to the ion exchange treated water after the ion exchange treatment in the ion exchange treatment tank 12 from the flocculant addition path 21 through aluminum sulfate (sulfate band) or polyaluminum chloride. (PAC) A flocculant such as (PAC) is added, and the suspended component in the ion-exchanged water is aggregated and precipitated by the flocculant, thereby comprising supernatant water not containing the suspended component and the suspended component aggregated with the flocculant. A coagulation sedimentation step for separating the sludge into sludge is performed. In the coagulation sedimentation tank 13, a treated water outlet path 22 for leading the supernatant water as treated water to a post-treatment facility such as a filtration basin, and the precipitated sludge are extracted. And a sludge extraction path 23 for feeding to the solid-liquid mixing and separation tank 15.

  The regeneration means 14 is for performing a regeneration step of regenerating the anion exchange resin having adsorbed the soluble organic component in the ion exchange treatment tank 12 into a reusable state, and the ion exchange treatment tank By treating the anion exchange resin flowing from 12 through the resin regeneration path 24 with a sodium chloride aqueous solution having a predetermined concentration, negatively charged organic substances adsorbed on the anion exchange resin and chloride ions in the sodium chloride aqueous solution or The anion exchange resin is regenerated by exchanging chloride ions. The regenerated anion exchange resin is circulated to the ion exchange treatment tank 12 through the recycle resin circulation path 25 and reused, and the regenerated waste liquid containing negatively charged organic substances desorbed from the anion exchange resin is regenerated waste liquid lead-out path. 26 to the solid-liquid mixing and separation tank 15.

  The solid-liquid mixing / separation tank 15 includes a solid-liquid mixing unit 15a that performs a solid-liquid mixing step of mixing the sludge from the sludge extraction path 23 and the recycled waste liquid from the recycled waste liquid outlet path 26, and the solid-liquid mixing section. A sludge concentration unit 15b that performs a sludge concentration step of concentrating and separating solids (sludge) in the solid-liquid mixture mixed in 15a, and a part of the negatively charged organic substances in the regenerated waste liquid When mixed with sludge in the liquid mixing unit 15a, the concentration of organic substances in the liquid is reduced due to the action of the flocculant. The sludge concentrated and separated in the sludge concentrating section 15b is drawn out to the sludge extraction path 27 and sent to the sludge treatment facility 16, and the liquid component separated from the sludge in the sludge concentrating section 15b is returned to the liquid component returning path by the liquid component returning process. The liquid component returned to the raw water tank 11 from 28 is mixed with the raw water and reprocessed.

The reference example of the water treatment facility shown in FIG. 2 replaces the positions of the ion exchange treatment tank 12 and the coagulation sedimentation tank 13 in the first embodiment, arranges the coagulation sedimentation tank 13 at the subsequent stage of the raw water tank 11, and the coagulation The example which has arrange | positioned the ion exchange treatment tank 12 in the back | latter stage of the precipitation tank 13 is shown. In addition, in the following description, the same code | symbol is attached | subjected to the component same as the component of the water treatment facility shown to the said 1st form example, and detailed description is abbreviate | omitted.

In this reference example, the raw water from the raw water tank 11 first flows into the coagulation sedimentation tank 13, and the suspended components in the raw water are aggregated and precipitated by the coagulant added from the coagulant addition path 21. The supernatant water is introduced into the ion exchange treatment tank 12 and brought into contact with the anion exchange resin, so that the soluble organic component contained in the raw water is adsorbed on the anion exchange resin and removed from the raw water.

  As in the first embodiment, the anion exchange resin used in the ion exchange treatment tank 12 is introduced into the regeneration means 14 from the resin regeneration path 24 and regenerated with a sodium chloride aqueous solution, and the regenerated anion exchange resin. Is recycled to the ion exchange treatment tank 12 through the recycled resin circulation path 25 and reused. Furthermore, the sludge extracted from the coagulation sedimentation tank 13 to the sludge extraction path 23 and the regenerated waste liquid led out from the regenerating means 14 to the regenerated waste liquid lead-out path 26 are mixed in the solid-liquid mixing section 15 a of the solid-liquid mixing and separation tank 15. The liquid components mixed and taken in the sludge with negatively charged organic substances in the reclaimed waste liquid and separated from the sludge by the sludge concentration unit 15 b are returned to the raw water tank 11 through the liquid component return path 28. The treated water from which the soluble organic components have been removed in the ion exchange treatment tank 12 is sent from the treated water lead-out path 22 to the subsequent equipment.

As shown in the first embodiment and the reference example , the regenerated waste liquid generated when regenerating the anion exchange resin adsorbing the soluble organic components in the raw water and the suspended components in the raw water are aggregated with a flocculant. Since the soluble organic component in the recycled waste liquid can be taken into the sludge by mixing with the sludge that has been made to react, the liquid component separated from the sludge can be mixed with the raw water and reprocessed. Thereby, it can process in an installation, without discharging | emitting reproduction | regeneration waste liquid outside, The closed systemization of the water treatment equipment using an ion exchange resin can be achieved. Furthermore, in the water treatment facilities shown in both embodiments, not only the soluble organic components can be reduced, but also the trihalomethane production ability (THMFP) can be reduced, the chromaticity can be improved, and the chlorine demand can be reduced.

Therefore, when the water treatment facility is provided at the latter stage of the water treatment facility shown in the first embodiment and the reference example , the organic matter load of the water treatment facility is reduced, so that the quality of the treated water in the water purification facility is improved. Since the amount of flocculant added can be reduced, the aggregation can be improved. In addition, the amount of ozone in advanced water purification treatment can be reduced.

Table 1 shows the UV absorbance and chromaticity of the liquid components when the sludge extracted from the coagulation sedimentation tank 13 is mixed with the reclaimed waste liquid derived from the regenerating means 14 at a ratio of 0.2 to 5.0% by volume. An example of the measurement result is shown. From the results of Table 1, in the case of the sludge used in this experiment, compared with the calculated value, the soluble organic matter in the liquid component is taken into the sludge by mixing the recycled waste liquid with several percent of sludge. It can be seen that the actual measurement value is significantly reduced, and the ultraviolet absorbance and chromaticity of the liquid component are improved.

  In addition, for the contact between the raw water and the anion exchange resin in the ion exchange treatment tank, the separation and recovery of the anion exchange resin after the contact with the raw water, use a general apparatus configuration used in this type of apparatus. The anion exchange resin regeneration means can also employ a general equipment configuration. Further, the present invention is suitable for the treatment of raw water having a high concentration of soluble organic components, but the properties of the raw water are not particularly limited, and river surface water and lake water having relatively high concentrations of soluble organic components. It can also be applied to water sources such as underground water and underground water. Furthermore, the solid-liquid mixing / separation tank may separate liquid components only by solid-liquid separation by natural sedimentation or the like without performing concentration.

  DESCRIPTION OF SYMBOLS 11 ... Raw water tank, 12 ... Ion exchange treatment tank, 13 ... Coagulation sedimentation tank, 14 ... Regeneration means, 15 ... Solid-liquid mixing separation tank, 15a ... Solid-liquid mixing part, 15b ... Sludge concentration part, 16 ... Sludge treatment equipment, DESCRIPTION OF SYMBOLS 21 ... Flocculant addition path, 22 ... Treated water extraction path, 23 ... Sludge extraction path, 24 ... Resin regeneration path, 25 ... Recycled resin circulation path, 26 ... Regenerated waste liquid extraction path, 27 ... Sludge extraction path, 28 ... Liquid Component return route

Claims (4)

An ion exchange step in which raw water is brought into contact with an anion exchange resin to remove soluble organic components contained in the raw water, and a flocculant is added to the raw water from which the soluble organic components have been removed in the ion exchange step. A coagulation sedimentation step of coagulating and separating suspended components contained in water, and a regeneration step of regenerating the anion exchange resin adsorbing the soluble organic component in the ion exchange step using a sodium chloride aqueous solution; A solid-liquid mixing / separating step of mixing the regenerated waste liquid generated by regenerating the anion exchange resin in the regenerating step and the sludge precipitated and discharged in the coagulating sedimentation step, and the solid-liquid mixing / separating step A liquid component returning step of extracting a liquid component in the mixed solid-liquid mixture and mixing it with the raw water. The solid-liquid mixing and separating step includes a mixing stage for mixing the recycled waste liquid and the sludge, and a sludge concentration stage for concentrating and separating sludge in the mixed solid-liquid mixture, and mixing with raw water. The water treatment method according to claim 1 , wherein the liquid component is extracted at the sludge concentration stage . The flocculant is added to the ion exchange treatment tank that removes soluble organic components contained in the raw water by bringing the raw water into contact with the anion exchange resin, and the raw water from which the soluble organic components have been removed in the ion exchange treatment tank. The aggregated sedimentation tank that aggregates and separates the suspended components contained in the raw water and precipitates and the anion exchange resin that has adsorbed the soluble organic components in the ion exchange treatment tank are regenerated using an aqueous sodium chloride solution. A solid-liquid mixing / separation tank for mixing the regenerating means, the regenerated waste liquid generated by regenerating the anion exchange resin with the regenerating means, and the sludge precipitated and discharged in the coagulating sedimentation tank; and the solid-liquid mixing A water treatment facility comprising a liquid component return path for extracting a liquid component in a solid-liquid mixture mixed in a separation tank and mixing the extracted liquid component with the raw water. The solid-liquid mixing and separation tank includes a mixing unit that mixes the recycled waste liquid and the sludge, and a sludge concentration unit that concentrates and separates sludge in the mixed solid-liquid mixture, and the liquid component return path is The water treatment facility according to claim 3, wherein the separated water generated in the sludge concentration unit is mixed with the raw water.

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