JP5199050B2 - Water treatment apparatus and water treatment method - Google Patents

Description

  The present invention relates to a water treatment apparatus for removing any object to be removed from treated raw water.

Conventionally, there is a technique for aggregating impurities by reacting metal ions eluted in the water to be treated with the impurities (see Patent Document 1). In addition, there is a sewage treatment technology for supplying eluted iron ions or aluminum ions to a biofilm filtration tank (see Patent Documents 2 to 7).
JP 2006-122840 A Japanese Patent No. 3948779 JP 2006-110482 A JP 2008-194631 A JP 2007-203233 A JP 2005-246328 A JP 2007-237027 A

  One of the main components that generate scale on the surface in contact with water and accumulate as evaporation residue is soluble silica dissolved in water. The scale generation causes, for example, piping blockage or a reduction in heat exchange efficiency of the heat exchanger. Moreover, residue accumulation causes a performance drop and a significant increase in maintenance in a humidifier or boiler steam generator. For this reason, conventionally, as a silica removal technique, removal using a reverse osmosis membrane (hereinafter referred to as reverse osmosis membrane method), removal using an ion exchange resin (hereinafter referred to as ion exchange membrane method), and aggregation and precipitation separation by adding a flocculant (hereinafter referred to as aggregation) Agent addition method), coagulation precipitation separation by electrolysis (hereinafter, electrolysis method), and the like have been proposed.

  Here, when the reverse osmosis membrane method is employed, silica is also the most causative substance for membrane clogging, and the membrane life is greatly shortened, resulting in an enormous operating cost. Therefore, the reverse osmosis membrane method is not suitable for treating raw water having a high silica concentration as raw water for a pure water plant. Further, when the ion exchange membrane method is adopted, technically, silica can be surely adsorbed and removed, but the operating cost is higher than that of the reverse osmosis membrane method. Depending on the amount of silica removed, assuming the treatment of general groundwater (silica concentration 50 to 100 ppm), the treatment cost is several thousand yen or more per ton, and a purification cost much higher than that of ultrapure water occurs. Practical use is difficult. Further, it has been proved that the flocculant addition method is very inefficient for use in removing silica at a level of groundwater or tap water, and the flocculant addition method is not suitable for practical use.

  In the electrolysis method, metal ions such as aluminum ions, which are effective for aggregating action, are eluted from the electrodes by electrolysis, thereby improving the reaction efficiency with silica ions having a weakly acidic negative charge. Further, in the electrolysis method, the adsorption of the colloidal substance by aluminum hydroxide is promoted by the effect of increasing the amount of hydroxide ions in the treated water by the generation of hydrogen gas from the negative electrode.

6 and 7 are diagrams showing the configuration of a conventional apparatus for removing a substance to be removed by electrolysis. The apparatus shown in FIG. 6 separates and removes an electrolysis reaction tank in which electrolysis processing is performed on the raw raw water in order from the upstream in the flow of water to be treated, and an object to be removed by precipitation of aggregates. A sedimentation tank in which In addition to the same electrolytic reaction tank and precipitation tank as in FIG. 6, the apparatus shown in FIG. 7 promotes the contact reaction between the aggregate generated in the electrolytic reaction tank and the object to be removed. It has a slow stirring tank for shortening the sedimentation time of the aggregate in the sedimentation tank by growing it into a large floc.

  An electrolysis method capable of removing silica at a relatively low cost is a technology that is highly practical. However, performance, cost, and device size are not sufficient, and it is essential to achieve higher performance, lower cost, and compactness. The relationship between performance, cost, and device size is a trade-off relationship. For example, to improve the removal performance, it can be achieved by eluting more metal ions and increasing the reaction time. However, the increase in the amount of elution increases the frequency of replacement of the metal electrode and significantly increases the running cost. End up. The replacement cost of the metal electrode in the running cost in this method is 50% or more, and an increase in electrode consumption is not desirable. Moreover, in order to lengthen reaction time, it is necessary to enlarge an electrolysis reaction tank, resulting in an increase in apparatus cost and an increase in installation space. On the other hand, the downsizing and cost reduction of the device size sacrifices the removal performance.

  In view of the problems described above, an object of the present invention is to improve the removal performance of an object to be removed by a water treatment apparatus without incurring an increase in cost or an increase in apparatus size.

  In order to solve the above-described problems, the present invention mixes the precipitate in which aggregates in the electrolyzed water generated by the electrolysis process are precipitated with the electrolyzed water before the precipitation process. This makes it possible to improve the removal performance of the object to be removed by the water treatment device without incurring an increase in cost or an increase in device size.

  Specifically, the present invention relates to an electrolysis unit that performs an electrolysis process on the treated raw water including a predetermined removal target, and the removal target included in the electrolysis process water generated by the electrolysis unit. A water treatment apparatus comprising: precipitation means for precipitating aggregates; and mixing means for mixing at least part of the precipitate precipitated by the precipitation means with the electrolyzed water generated by the electrolysis means. is there.

  The water treatment apparatus according to the present invention is an apparatus for removing a predetermined object to be removed from raw water to be treated. That is, the treated raw water to be subjected to electrolysis treatment is raw water containing a removal target, and examples of the removal target include soluble silica dissolved in the treated raw water. However, the removal target is not limited to soluble silica, and in the water treatment apparatus according to the present invention, as the removal target, silica, iron, Mn (manganese), F (fluorine), SS (Suspended Solids), etc. A wide range of substances can be removed, and the object to be removed is not limited to a specific substance.

  In addition, the electrolysis process by the electrolysis means is a process in which an electrolysis reaction is caused by applying electric energy from the outside to the treated raw water, and the removal target is aggregated and separated. For example, by eluting metal ions such as aluminum ions from the electrode, the reaction efficiency with silica ions having a weakly acidic negative charge can be improved. For this reason, the electrolyzed water produced | generated by performing an electrolysis process contains the aggregate of a removal target object. In addition, in order to elute aluminum ion, the said electrolysis means may perform the electrolysis process which uses an aluminum plate as a positive electrode with respect to the said process raw | natural water.

Here, the aggregate is precipitated by the precipitation means, so that the removal target is removed from the electrolyzed water, but in the present invention, the ability to take the removal target into the precipitated precipitate still remains. In particular, by mixing at least a part of the precipitate, which is a high-concentration aggregate, with the electrolyzed water, the second between the precipitate and the removal target remaining in the electrolyzed water. This promotes the agglomeration of the object to be removed. At the same time, it is possible to obtain the effect of improving the sedimentation property of the aggregate and further improving the dewatering performance of the excess sludge by taking the object to be removed into the aggregate to the maximum.

  By doing in this way, the water treatment apparatus according to the present invention makes it possible to obtain a removal performance that is higher than the conventional one even with the same amount of electrode consumption and the same apparatus size as the conventional one. That is, according to this invention, the removal performance of the removal target object by a water treatment apparatus can be improved, suppressing consumption of an electrode and the enlargement of an electrolysis reaction tank. Moreover, the amount of dewatered sludge can be reduced by improving the dewatering performance of excess sludge as described above.

  The electrolysis means performs electrolysis treatment on the treated raw water introduced into the electrolysis reaction tank, and the precipitation means sets the electrolyzed water sent from the electrolysis reaction tank to the precipitation tank. The agglomerate is precipitated by being retained in the step, and the mixing means mixes at least a part of the precipitate precipitated in the precipitation tank with the electrolyzed water before being sent to the precipitation tank. Also good.

  Here, the electrolysis reaction tank is a tank into which treated raw water is introduced, and the precipitation tank is a tank to which electrolysis treated water that has been subjected to electroreaction processing in the electrolysis reaction tank is sent. That is, in the water treatment apparatus, an electrolysis reaction tank is provided on the upstream side of the water flow to be treated, and a precipitation tank is provided on the downstream side. In the present invention, at least a part of the precipitate precipitated in the settling tank is mixed with the electrolyzed water before being sent to the settling tank, in other words, by returning the precipitate to the upstream side, The precipitate is mixed with the treated water to promote the aggregation of the object to be removed.

  In addition, the mixing means may include at least a part of the precipitate precipitated in the settling tank with respect to the mixed reaction tank provided in a path through which the electrolyzed water is sent from the electrolysis reaction tank to the settling tank. The precipitate is mixed with the electrolyzed water, and the water treatment apparatus according to the present invention includes a stirring means for promoting mixing of the precipitate and the electrolyzed water in the mixing reaction tank. Further, it may be provided.

  The mixing means sends at least a part of the sediment precipitated in the sedimentation tank to a pipe provided in a path through which the electrolyzed water is sent from the electrolysis reaction tank to the precipitation tank. Thus, the electrolyzed water and the precipitate may be mixed.

  That is, in the present invention, in addition to the electrolytic reaction tank and the precipitation tank, a mixed reaction tank or a pipe for mixing the electrolytically treated water sent from the electrolytic reaction tank and the precipitate sent from the precipitation tank Is further provided to promote agglomeration of the object to be removed using the precipitate. Moreover, the shape of the piping for mixing may have a shape suitable for promoting mixing, for example, a meandering shape instead of a straight line.

  In addition, the sediment sent from the settling tank for mixing is sent together with the electrolyzed water in the settling tank, and the amount of sludge (electrolyzed water containing the precipitate) sent from the settling tank for mixing. May be 5 to 50% with respect to the amount of the electrolyzed water sent from the electrolysis reactor for mixing.

  The present invention can also be understood as an invention of a water treatment method. For example, the present invention provides an electrolysis step for performing electrolysis treatment on treated raw water containing a predetermined removal object, and an aggregate of the removal object contained in the electrolysis treatment water generated in the electrolysis step. A water treatment method in which a precipitation step for precipitating and a mixing step for mixing at least a part of the precipitate precipitated in the precipitation step with the electrolysis-treated water generated in the electrolysis step are performed. is there.

  According to the present invention, it is possible to improve the removal performance of an object to be removed by a water treatment apparatus without incurring an increase in cost or an increase in apparatus size.

  An embodiment of a water treatment device according to the present invention will be described with reference to the drawings.

<First embodiment>
FIG. 1 is a schematic diagram illustrating a configuration of a water treatment apparatus 1 according to the first embodiment. The water treatment apparatus 1 includes an electrolysis reaction tank 12, a mixing reaction tank 14, and a precipitation tank 16 in order from the upstream in the flow of water to be treated. The electrolysis reaction tank 12 is connected with a pipe 11 for introducing treated raw water (treated water), and the electrolysis reaction tank 12 and the mixed reaction tank 14 are connected with a pipe 13. The mixing reaction tank 14 and the settling tank 16 are connected by a pipe 15, and the settling tank 16 is connected to a pipe 17 for sending treated water that has been subjected to removal processing of a removal target. .

  Furthermore, the sedimentation tank 16 is connected to a pipe 23 and a pump 23 for feeding the sediment 22 precipitated in the lower part of the sedimentation tank 16 together with the water in the sedimentation tank 16. The contained water is sent to the mixing reaction tank 14 or the outside through the pipe 18. Hereinafter, in this embodiment, the water containing a sediment sent out from the sedimentation tank 16 is called sludge. Here, the destination of the sludge is controlled by controlling the valve 24 and the valve 25. Specifically, when the valve 24 is open, the sludge is sent to the mixing reaction tank 14, and when the valve 25 is open, the sludge is sent to the outside.

  The electrolysis reaction tank 12 is a tank in which raw raw water to be treated is introduced via the pipe 11 and electrolysis is performed on the raw raw water. In the electrolysis treatment according to the present embodiment, aluminum ions are eluted from the aluminum electrode (a positive electrode using an aluminum plate; not shown) provided in the electrolysis reaction tank 12 into the water in the electrolysis reaction tank 12. Thus, the reaction with a weakly acidic negatively charged silica ion is promoted. In the electrolysis method, the adsorption of the colloidal substance by aluminum hydroxide is promoted by the effect of increasing the amount of hydroxide ions in the treated water by the generation of hydrogen gas from the negative electrode. By such an electrolysis process, aggregates are generated in the electrolysis reaction tank 12. Water containing aggregates (hereinafter referred to as electrolyzed water) that has been subjected to electrolysis in the electrolysis reaction tank 12 is sent to the mixing reaction tank 14 via the pipe 13.

  The mixing reaction tank 14 includes electrolysis treated water sent from the electrolysis reaction tank 12 via the pipe 13, and sludge (electrolysis treated water containing precipitates) returned from the precipitation tank 16 via the pipe 18. Is a tank for promoting further reaction between the aggregates in the electrolyzed water and the remaining silica ions and colloidal silica without being removed. In addition, when the reaction that proceeds in the electrolysis reaction tank 12 is the first reaction, the reaction that proceeds in the mixed reaction tank 14 is the second reaction. Moreover, in this embodiment, in order to accelerate | stimulate mixing with the electrolysis process water sent from the electrolysis reaction tank 12, and the sludge sent from the sedimentation tank 16, stirring with the stirring apparatus 21 is performed. The agglomeration of the object to be removed that has been mixed in the mixing reaction tank 14 has progressed, and the electrolyzed water that contains more agglomerates than the time when it is sent out from the electrolysis reaction tank 12 And sent to the sedimentation tank 16 via the pipe 15.

The sedimentation tank 16 is a tank into which the electrolyzed water sent from the mixing reaction tank 14 is introduced and the aggregates are separated from the electrolyzed water. In the present embodiment, the electrolytically treated water sent from the mixing reaction tank 14 stays in the precipitation tank 16 for a predetermined time, so that the removal target object is separated and removed by precipitation of aggregates. The settled aggregate is accumulated in the lower part of the sedimentation tank 16 and becomes sludge. The second reaction in the mixed reaction tank 14 improves the sedimentation property of the sludge in addition to improving the removal performance of the object to be removed. For this reason, although it depends on the return rate of sludge, the amount of water in the settling tank 16 will increase by 5 to 30% compared to the case where the return rate of sludge is not returned, for example, in the range of 5 to 30%. It seems that the tank 16 needs to be enlarged. However, since the time required for the precipitation is shortened by improving the sedimentation property of the aggregate, in practice, it is possible to employ a sedimentation tank 16 that is equivalent to or more compact than the conventional one. At least a part of this sludge is returned to the mixing reaction tank 14 via the pump 23 and the pipe 18, so that the second sludge is mixed with the electrolyzed water sent from the electrolysis reaction tank 12 described above. Used in the reaction of In this case, sludge can be returned by driving the pump 23 with the valve 24 opened. Moreover, when the sludge settles more than a predetermined amount, the sludge can be discharged outside by driving the pump 23 with the valve 25 opened.

  When the electrolyzed water stays in the settling tank 16 for a predetermined time, the agglomerates settle to the lower part of the settling tank 16, and an object to be removed (such as silica in this embodiment) is removed from the upper part of the settling tank 16. Treated water remains. The treated water from which the removal target has been removed is sent to the outside through the pipe 17 and can be used for various purposes.

<Second Embodiment>
FIG. 2 is a schematic diagram showing a configuration of a water treatment device 1b according to the second embodiment. The water treatment apparatus 1b includes an electrolysis reaction tank 12, a mixing reaction tube 19, and a precipitation tank 16 in order from the upstream in the flow of water to be treated. The water treatment apparatus 1b according to the present embodiment is the water treatment apparatus 1 according to the first embodiment shown in FIG. 1 except that a mixed reaction tube 19 is adopted instead of the mixing reaction tank 14. And roughly the same.

  The mixing reaction tube 19 mixes the electrolyzed water sent from the electrolysis reaction tank 12 via the pipe 13 and the sludge returned from the sedimentation tank 16 via the pipe 18, so that the electrolyzed water is mixed. It is piping for accelerating the further reaction with the removal object (a silica ion, colloidal silica, etc.) which remain | survived without removing the aggregate inside. In the present embodiment, in order to promote mixing of the electrolyzed water sent from the electrolysis reaction tank 12 and the sludge sent from the settling tank 16, and to ensure a sufficient time for the reaction, a mixing reaction tube 19 is a pipe having a meandering shape and a length sufficient to ensure a sufficient time for the reaction. The electrolyzed water that has been agglomerated with respect to the object to be removed that has been mixed in the mixing reaction tube 19 and that contains more agglomerates than the time when it was sent out from the electrolysis reaction tank 12, And sent to the sedimentation tank 16 via the pipe 15. According to the water treatment device 1b shown in the present embodiment, the mixing reaction tank 14 and the stirring device 21 are not necessary and are replaced by the mixing reaction tube 19, which is more advantageous in terms of cost.

<Third embodiment>
FIG. 3 is a schematic diagram showing a configuration of a water treatment device 1c according to the third embodiment. The water treatment device 1c includes an electrolysis reaction tank 12c and a precipitation tank 16 in order from the upstream in the flow of water to be treated. In addition, the electrolytic reaction tank 12c is connected to a pipe 11 for introducing treated raw water, and the electrolysis reaction tank 12c and the settling tank 16 are connected by a pipe 15c. A pipe 17 for sending treated water that has been subjected to removal treatment of the removal object to the outside is connected.

Furthermore, the sedimentation tank 16 is connected to a pipe 23 and a pump 23 for feeding the sediment 22 precipitated in the lower part of the sedimentation tank 16 together with the water in the sedimentation tank 16. The contained water (sludge) is sent to the electrolysis reaction tank 12c or the outside through the pipe 18c. Here, the destination of the sludge is controlled by controlling the valve 24 and the valve 25. Specifically, in a state where the valve 24 is opened, sludge is sent to the electrolysis reaction tank 12c,
In the state where the valve 25 is opened, the sludge is sent to the outside.

  In the present embodiment, the electrolysis reaction tank 12c is a tank in which raw raw water to be treated is introduced via the pipe 11 and electrolysis is performed on the raw raw water. The contents of the electrolysis process performed in the electrolysis reaction tank 12c are substantially the same as the contents described in the first embodiment, but the water treatment apparatus 1c according to the present embodiment includes the electrolysis reaction tank 12c, It differs from the water treatment apparatuses 1 and 1b shown in the first embodiment or the second embodiment in that sludge is returned from the sedimentation tank 16 through the pipe 18c. That is, in the electrolysis reaction tank 12c in the present embodiment, the sludge returned from the precipitation tank 16 is mixed with the water in the electrolysis reaction tank 12c, and in parallel with the formation of aggregates by the electrolysis treatment, The reaction between the aggregate and the removal target is promoted.

  In the water treatment apparatus 1c according to the present embodiment, sludge is put into the electrolysis reaction tank 12c having a relatively long residence time to react with the electrolyzing process. According to the water treatment device 1c shown in the present embodiment, it is not necessary to separately prepare equipment for the reaction (for example, the mixing reaction tank 14 and the mixing reaction tube 19), so that the entire water treatment device 1c is compact and It can be built at low cost.

  The electrolyzed water that has been subjected to electrolysis and sludge mixing in the electrolysis reaction tank 12c is sent to the settling tank 16 via the pipe 15c. The agglomerates sent to the settling tank 16 become sludge by collecting in the lower part of the settling tank 16. At least a part of the sludge is returned to the electrolysis reaction tank 12c via the pump 23 and the pipe 18c.

  In order to confirm the effectiveness of the present invention with respect to the prior art, the test apparatus of the present invention and the test apparatus of the prior art were manufactured, and a comparative experiment on the removal performance for silica contained in the treated raw water was conducted. Here, as the test apparatus of the present invention, the water treatment apparatus 1 having the configuration shown in the first embodiment described with reference to FIG. 1 is adopted, and the test apparatus of the prior art has the configuration shown in FIG. And the apparatus having the configuration shown in FIG.

  FIG. 4 is a diagram showing the mixing reaction tank 14 used in the test apparatus according to the present example, and FIG. 5 is a diagram showing the stirring propeller used in the mixing reaction tank 14 of the test apparatus according to the present example. It is. In the test apparatus, a square-shaped mixed reaction tank 14 having a bottom surface of 250 mm on one side and a depth of 400 mm is used as an internal dimension, and electrolyzed water is introduced into the mixed reaction tank 14 to a depth of 270 mm for testing. It was conducted. In addition, since the process in the electric field treatment tank is the same for all three apparatuses, the power cost required for electrolysis and the consumption of the aluminum electrode are also the same. Other experimental conditions are shown in Table 1.

  As a result of the test under the above conditions, it was confirmed that the removal performance of the water treatment device 1 according to the present invention was improved by about 30% as compared with the device according to the prior art. The silica removal results according to this example are shown in Table 2.

  In the prior art shown in FIG. 7, a stirring tank is added to the prior art shown in FIG. For this reason, in the prior art shown in FIG. 7, compared with the prior art shown in FIG. 6, the contact reaction between the agglomerate generated in the electrolysis reaction tank and the object to be removed is increased by 10 minutes, so that some removal performance is obtained. The improvement was confirmed. However, the improvement effect of the removal performance is much smaller than the reaction of returning the high concentration aggregate (sludge) of the present invention and mixing it.

  In this embodiment, the mixing reaction processing time is 10 minutes and the sludge return rate is 30%, but this is preferably set to an optimum value depending on the target removal rate. Moreover, when the sludge return rate is high, the reaction time can be shortened. In addition, since the time required for sedimentation is improved by the effect of improving the sedimentation property of the aggregates by returning the sludge, and the increase in the amount of water in the sedimentation tank 16 is offset, it is not necessary to increase the size of the sedimentation tank 16. In carrying out the present invention, by selecting an optimum sludge return rate according to the concentration of the removal target, it is possible to achieve downsizing of the entire apparatus and reduction of processing costs. As an approximate range, the mixing reaction time is 1 minute to 60 minutes, and the sludge return rate is 5 to 50%. When the return rate is 50%, the amount of inflow from the mixing reaction tank 14 to the settling tank 16 is 1.5 times the amount of treated water.

Moreover, also when the water treatment apparatus 1b having the configuration shown in the second embodiment described with reference to FIG. 2 is adopted as a test apparatus, a conventional test apparatus for silica contained in treated raw water and A comparative experiment was conducted. In this example, a mixed reaction tube 19 having a length and capacity capable of ensuring a reaction time of 1 minute or longer was employed, and an experiment was conducted under the conditions of a sludge return rate of 20% and a reaction time of 5 minutes. Other conditions are the same as those in Example 1. As a result of the experiment, the silica removal rate in this example was 70%.

It is the schematic which shows the structure of the water treatment apparatus which concerns on 1st embodiment. It is the schematic which shows the structure of the water treatment apparatus which concerns on 2nd embodiment. It is the schematic which shows the structure of the water treatment apparatus which concerns on 3rd embodiment. It is a figure which shows the mixing reaction tank used in the test apparatus which concerns on an Example. It is a figure which shows the stirring propeller used in the mixing reaction tank of the test apparatus which concerns on an Example. It is a figure which shows the structure of the conventional apparatus which removes the removal target substance by the electrolysis method. It is a figure which shows the structure of the conventional apparatus which removes the removal target substance by the electrolysis method.

Explanation of symbols

1, 1b, 1c Water treatment device 12 Electrolytic reaction tank 14 Mixing reaction tank 16 Precipitation tank 19 Mixing reaction tube

Claims (6)

And electrolysis means for advancing the first reaction to have line electrolysis process, to agglomerate the removal target relative to the processing raw water containing a predetermined removal target,
Precipitation means for precipitating aggregates of the removal target contained in the electrolyzed water generated by the electrolysis means;
Mixing means for mixing at least a part of the precipitate precipitated by the precipitation means with the electrolyzed water generated by the electrolysis means ,
The mixing means mixes at least a part of the precipitate in the electrolysis-treated water after the electrolysis treatment for causing the first reaction to proceed, so that the electrolysis-treated water in the electrolysis-treated water is mixed. Proceed with a second reaction to further agglomerate the agglomerates,
Water treatment equipment. The electrolysis means performs electrolysis treatment on the treated raw water introduced into the electrolysis reaction tank,
The precipitation means precipitates the agglomerates by retaining the electrolyzed water sent from the electrolysis reaction tank in the settling tank,
The mixing means sends at least a part of the precipitate precipitated in the settling tank to a mixed reaction tank provided in a path through which the electrolyzed water is sent from the electrolysis reaction tank to the settling tank. Then, the precipitate is further mixed with the electrolyzed water before being sent to the settling tank, and further provided with stirring means for promoting the mixing of the precipitate and the electrolyzed water in the mixed reaction tank.
The water treatment apparatus according to claim 1 . The electrolysis means performs electrolysis treatment on the treated raw water introduced into the electrolysis reaction tank,
The precipitation means precipitates the agglomerates by retaining the electrolyzed water sent from the electrolysis reaction tank in the settling tank,
The mixing means is provided in a path through which the electrolyzed water is sent from the electrolysis reaction tank to the settling tank, and has a meandering shape or a length capable of securing time for the second reaction. By sending at least a part of the sediment precipitated in the sedimentation tank to the piping, the electrolyzed water before being sent to the sedimentation tank and the sediment are mixed.
The water treatment apparatus according to claim 1 . The removal object is soluble silica dissolved in the treated raw water.
The water treatment apparatus according to any one of claims 1 to 3 . The electrolysis means performs an electrolysis process using an aluminum plate as a positive electrode for the treated raw water.
The water treatment apparatus according to any one of claims 1 to 4 . And electrolysis step of advancing the first reaction to have line electrolysis process, to agglomerate the removal target relative to the processing raw water containing a predetermined removal target,
A precipitation step of precipitating aggregates of the removal target contained in the electrolyzed water produced in the electrolysis step;
And a mixing step of mixing at least a part of the precipitate precipitated in the precipitation step with the electrolyzed water generated in the electrolysis step, and
In the mixing step, at least a part of the precipitate is mixed in the electrolysis-treated water after the electrolysis treatment that causes the first reaction to proceed, so that the inside of the electrolysis-treated water A second reaction proceeds to further aggregate the aggregate.
Water treatment method.

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