TW202233530A - Urea treatment device and pure water production system - Google Patents

Abstract

A treatment device, which receives a water to be treated, decomposes the urea contained in the water to be treated and then discharges the treated water, includes an addition unit for adding a hypochlorite salt (for example, NaClO) and a bromide salt (for example, NaBr) as a urea decomposition agent to the water to be treated, and a plurality of reaction vessels (20) in which the decomposition reaction of the urea by the urea decomposition agent progresses. In the treatment device, the plurality of reaction vessels (20) are either disposed in parallel with a batch type decomposition reaction conducted in each reaction vessel, or disposed in series with the decomposition reaction conducted as a multistage completely mixed continuous reaction vessel.

Description

Urea treatment device and pure water production system

The present invention relates to a treatment device for decomposing urea in water to be treated, and a pure water production system including the treatment device.

A pure water production apparatus for producing pure water from raw water such as tap water, groundwater, industrial water, etc., is constructed by combining a reverse osmosis apparatus, an ion exchange apparatus, an ultraviolet oxidation apparatus, and the like, for example. In the case where urea is contained in the raw water, since urea is a substance that cannot be easily removed by reverse osmosis, ion exchange and ultraviolet oxidation, urea remains in the produced pure water, resulting in TOC of the pure water. (total organic carbon; total organic carbon) concentration increased. In the case of producing ultrapure water with a particularly high purity for semiconductor manufacturing and the like, the upper limit of the TOC concentration in the produced ultrapure water is set more strictly. As a pretreatment for the step of producing pure water or ultrapure water from raw water, a step of removing urea from raw water is required. As for the step for removing urea contained in the raw water as the water to be treated, as described in Patent Documents 1 to 3, a step is known in which a bromide salt and a hypochlorite are added to the water to be treated. For example, sodium bromide and sodium hypochlorite are used to generate hypobromous acid, and then urea is decomposed by the hypobromous acid. [Existing Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 3546548 [Patent Document 2] Japanese Patent No. 5678436 [Patent Document 3] Japanese Patent No. 6279295

[Problems to be solved by the invention]

The step of adding a bromide salt and a hypochlorite to the water to be treated to decompose urea is a step that requires a low reaction rate and a long reaction time. Therefore, in the conventional technique, bromide salt and hypochlorous acid are added while continuously receiving the water to be treated in a single large-scale reaction tank as a premise for the continuous supply of treated water to a pure water production apparatus installed in a later stage. Salt. However, the water flow cannot be controlled in a single large-scale reaction tank, and an incomplete plug flow (plug flow) is formed in the reaction tank. As a result, the residence time is shortened due to the influence of the short diameter, and the urea treatment performance is deteriorated. In order to ensure a sufficient reaction time, the residence time in the reaction tank is set too much, so it is necessary to prepare a reaction tank larger than the original requirement.

An object of the present invention is to provide a processing apparatus which is used for decomposition of urea and can reduce the volume of the entire reaction tank, and a pure water production system including the processing apparatus as a pretreatment apparatus. [Technical means to solve the problem]

The treatment device of the present invention receives the water to be treated, decomposes the urea contained in the water to be treated, and discharges the treated water; the treatment device includes: adding means for adding bromide salt and hypochlorite to the water to be treated as a urea decomposer ; and a plurality of reaction tanks to carry out the decomposition reaction of urea with a urea decomposer. Bromide salts are, for example, sodium bromide, and hypochlorites are, for example, sodium hypochlorite.

In the processing apparatus of the present invention, a plurality of reaction tanks are arranged in series or in parallel. When a plurality of reaction tanks are connected in series, each reaction tank is provided with an addition means so that the whole is used as a multi-stage fully continuous stirred tank (CSTR) reaction apparatus for the decomposition reaction. In the case where the reaction tanks are arranged in a series of multiple stages, since the concentration of urea in the water to be treated is different in each reaction tank, a concentration gradient of urea is formed, so the reaction speed can be increased; as a result, the volume of the entire reaction tank can be reduced. . By increasing the number of reaction tanks arranged in series, as a whole, a plug flow reaction can be approached. On the other hand, when a plurality of reaction tanks are installed in parallel, each is used as a batch-type (batch-type) reaction tank, for example. When only one batch reaction tank is used, it is impossible to continuously receive the treated water or discharge the treated water continuously; however, for example, if one of the plurality of reaction tanks is used for receiving the treated water , and discharge the treated water from one of the remaining ones, by alternately alternating the reaction tank for receiving the water to be treated and the reaction tank for discharging the treated water, it is possible to perform batch-type decomposition treatment while, for example, continuous Discharge the treated water naturally. Since the batch-type reaction and the ideal plug-flow reaction are the most efficient reactions, by arranging a plurality of reaction tanks in parallel to perform the batch-type decomposition reaction, the overall size of the reaction tank can be reduced. volume of.

The pure water production system of the present invention includes at least an ion exchange device and a reverse osmosis device to which water having passed through the ion exchange device is supplied; the pure water production system includes the treatment device of the present invention as a pretreatment device. [Effect of invention]

According to the present invention, it is possible to obtain a processing apparatus for decomposing urea, and a pure water production system including the processing apparatus as a pretreatment apparatus, which can reduce the volume of the entire reaction tank.

Next, preferred embodiments of the present invention will be described with reference to the drawings.

The treatment device according to the present invention decomposes urea in the water to be treated and discharges the treated water continuously, and is preferably used as a pretreatment device in a pure water production system, for example. The treatment apparatus according to the present invention is characterized by comprising: adding means for adding bromide salt and hypochlorite to the water to be treated as a urea decomposer; and a plurality of reaction tanks for performing a decomposition reaction of urea with the urea decomposer, More specifically, the decomposition reaction of urea is a decomposition reaction of urea promoted by hypobromous acid or hypobromite generated by a urea decomposer. Although the urea decomposer is composed of bromide salt and hypochlorite, the bromide salt is preferably water-soluble, for example, sodium bromide (NaBr) is used. As the hypochlorite, for example, sodium hypochlorite (NaClO) is used. In the following description, the case where sodium bromide and sodium hypochlorite are used as a urea decomposer is demonstrated. In addition, in the present invention, the case of arranging a plurality of reaction tanks in parallel and the case of arranging in series are conceivable, but the case of arranging the reaction tanks in parallel will be explained with the first embodiment, and the series arrangement will be explained with the second embodiment. situation.

[First Embodiment] FIG. 1 shows a processing apparatus according to a first embodiment of the present invention. The processing apparatus 10 shown in FIG. 1 includes a plurality of reaction tanks 20 arranged in parallel, and each reaction tank 20 performs the decomposition reaction of urea in a batch or semi-batch manner. The number of reaction tanks 20 arranged in parallel may be two, but three or more are preferred. In the example shown in the figure, the number of the reaction tanks 20 arranged in parallel is three. The inlet piping 21 is provided in the several reaction tanks 20, and is shared, and it receives the supply of to-be-processed water. The inlet pipe 21 is provided for distributing the water to be treated to each reaction tank 20 , and the inlet of each reaction tank 20 is connected to the end of the inlet pipe 21 via the valve 23 , respectively. The valve 23 controls the supply of the treated water to the corresponding reaction tank 20 . A urea decomposer is injected into the inlet pipe 21, and the urea decomposer is an aqueous solution containing sodium bromide and sodium hypochlorite. The structure for injecting and adding the urea decomposer to the water to be treated in this way constitutes the addition means. An in-pipe mixer 22 is provided in the inlet piping 21 on the downstream side of the injection position of the urea decomposer so as to make the concentration of the urea decomposer in the water to be treated uniform. By providing the in-pipe mixer 22, the concentration of the urea decomposer in the water to be treated at the time of flowing into the reaction tank 20 becomes uniform. Instead of the in-pipe mixer 22, a mixer, a submersible pump, an aeration device, etc. can be used to make the concentration of the urea decomposer in the treated water uniform.

The outlet of each reaction tank 20 is connected to the outlet piping 25 via the valve 24, respectively. The valve 24 controls the discharge of the treated water from the reaction tank 20, which is obtained by performing the reaction in the reaction tank 20 to decompose the urea in the water to be treated with a urea decomposer. The treated water from each reaction tank 20 is discharged to the outside of the treatment apparatus 10 via the outlet piping 25 .

In the treatment apparatus 10 of the present embodiment, by the operation of the valves 23 and 24, the water to be treated is received in at least one reaction tank among the plurality of reaction tanks 20 provided, and the water to be treated is received from the other reactors except for the water to be treated. At least one reaction tank 20 other than the reaction tank 20 discharges the treated water; when the discharge of the water to be treated is completed, the reaction tank 20 for receiving the water to be treated and the reaction tank 20 for discharging the treated water are alternately alternated. Since the reaction tanks 20 from which the treated water is discharged are alternately alternated, the treated water can be continuously discharged at a predetermined flow rate through the outlet piping 25 even if the treatment is performed in batches in each of the reaction tanks 20 .

Considering the case where the decomposition reaction of urea is carried out in batches in the reaction tank 20, in the reaction tank 20, three stages of receiving the water to be treated, proceeding of the decomposition reaction of urea, and discharging of the treated water are successively carried out. . For example, when three reaction tanks 20 from A to C are arranged in parallel, the A reaction tank 20 will receive the water to be treated, that is, the water to be treated will be filled; at the same time, the B reaction tank 20 will be decomposed of urea The reaction is carried out in the C reaction tank 20 to discharge the treated water. After the water to be treated is discharged from the C reaction tank 20, the C reaction tank 20 will receive the treated water, the A reaction tank 20 will carry out the decomposition reaction of urea, and the B reaction tank 20 will carry out the discharge of the treated water. Furthermore, after the water to be treated is discharged from the B reaction tank 20, the water to be treated will be received in the B reaction tank 20, the decomposition reaction of urea will be carried out in the C reaction tank 20, and the treated water will be processed in the A reaction tank 20. discharge. After that, repeat this rotation. Each reaction tank 20 repeats the operations of receiving the water to be treated → decomposition reaction of urea → discharging of the treated water → receiving the water to be treated → . It is possible to perform batch-type urea decomposition treatment while continuously receiving the water to be treated and continuously discharging the treated water. If the number of the reaction tanks 20 installed in parallel is four or more, then two or more reaction tanks 20 other than the reaction tank 20 for receiving the water to be treated and the reaction tank 20 for discharging the treated water can be used to conduct urea Therefore, the ratio of the urea decomposition reaction in the operation repetition period of each reaction tank 20 is increased, and the use efficiency of the reaction tank 20 is improved accordingly, so the volume of the reaction tank 20 of the entire processing apparatus 10 can be reduced.

In this embodiment, the number of the reaction tanks 20 arranged in parallel may be two. In this case, for example, the water to be treated can be supplied to one of the reaction tanks 20 for a short period of time, and then the decomposition reaction of urea is carried out in the reaction tank 20; After the water is discharged from the other reaction tank 20, the functions of the two reaction tanks 20 can be reversed. At this time, although the treated water can be continuously discharged, the treated water cannot be continuously received. Alternatively, the treated water can be continuously received in one of the reaction tanks 20, and the decomposition reaction of urea can be carried out in the other reaction tank 20. Once the decomposition reaction of urea is completed, the treated water is discharged in a short time; The functions of the two reaction tanks 20 can be reversed when the receiving and discharging of the treated water are completed. At this time, although the water to be treated can be continuously received, the treated water cannot be continuously discharged.

In the example shown in FIG. 1, an in-pipe mixer 22 is provided in the inlet piping 21, but instead of the in-pipe mixer 22, a mixer, a submersible pump, or an aeration device, etc. may be provided in each reaction tank 20. stirring mechanism. In addition, as shown in FIG. 1 , the urea decomposer is added to the water to be treated by the inlet pipe 21; When the urea decomposer is added to the reaction tank 20 , for example, when the urea decomposer is added to the same reaction tank 20 while the water to be treated is poured into the reaction tank 20 , the urea decomposes in a half-batch type (half-batch type). Therefore, it is necessary to install a stirring mechanism in the reaction tank 20. In the case of performing a half-batch process in which the reaction tank 20 is filled with the water to be treated and the decomposition reaction of urea is also carried out, the filling time of the water to be treated is changed so that the water to be treated is changed. The reaction time change required to bring the urea concentration in the water to be treated to a predetermined value or less is the starting point when the water starts to fill up. At this time, the numerical range of the filling time of the treated water can be determined according to the capacity of the pump used for supplying the treated water to the reaction tank 20 and the reaction time.

The decomposition reaction of urea promoted by hypobromous acid is known to depend on the pH value of the water to be treated; and the adjustment of the pH value can be performed in the reaction tank 20 . Furthermore, in the present embodiment, a circulation pipe for circulating the water in the reaction tank 20 may be provided in each reaction tank 20, and a urea concentration meter may be installed in the circulation pipe to monitor the urea concentration to determine the reaction time from the reaction. Timing when the tank 20 discharges the treated water.

[Second Embodiment] FIG. 2 shows a processing apparatus according to a second embodiment of the present invention. The processing apparatus 10 shown in FIG. 2 is provided with the several reaction tank 20 arrange|positioned in series, and is comprised as the reaction apparatus of the multistage type complete continuous stirring tank as a whole. In the figure, two reaction tanks 20 are arranged in series; the inlet of the reaction tank 20 on the upstream side is connected to an inlet pipe 21 for receiving the supply of the water to be treated; the outlet of the reaction tank 20 on the downstream side is connected to a discharge pipe 21 Outlet piping 25 for treated water. Each reaction tank 20 is provided with an adding means for injecting a urea decomposer, which is an aqueous solution containing sodium bromide and sodium hypochlorite, and a stirring mechanism (not shown). The stirring mechanism is constituted by a mixer, a submersible pump, an aeration device, and the like.

When a plurality of reaction tanks 20 are arranged in series, since the concentration of urea in the water in the reaction tanks 20 varies with each reaction tank 20, when the processing apparatus 10 is viewed as a whole, a concentration gradient occurs, and it is possible to Improve reaction speed. From this point of view, in the example shown in FIG. 2 , two reaction tanks 20 are arranged in series, but in fact, the number of reaction tanks 20 arranged in series is preferably four or more.

In the treatment apparatus 10 of the present embodiment, the amount of the urea treatment agent injected into the reaction tank 20 may be changed for each reaction tank 20 . For example, in the reaction tanks 20 connected in series, the most upstream reaction tank 20 is filled with urea decomposer at all times, and the urea concentration in the water discharged from the most upstream reaction tank 20 is measured; if the urea concentration exceeds the specified value The urea decomposer is also injected into the reaction tank 20 of the next stage; in addition, the injection rate of the urea decomposer in the most upstream reaction tank 20 can be increased depending on the situation, and the urea concentration in the water discharged from the most upstream reaction tank 20 When the predetermined value or less is reached, the injection of the urea decomposer into the reaction tank 20 of the next stage is stopped. In the case of disposing three or more reaction tanks 20, it is also possible to measure the urea concentration in the water discharged from each reaction tank 20 to determine the injection amount of the urea decomposer in the reaction tank 20 on the upper stage side, And according to the determined injection amount, the addition means of the reaction tank 20 on the upper stage side is automatically controlled.

[Pure water production system] The treatment apparatus based on the present invention can be used as a pretreatment apparatus for producing pure water. FIG. 3 shows a pure water production system into which the treatment device of the present invention is introduced. The pure water production system shown in the figure is one that produces primary pure water from raw water. The raw water discharged from the exchanger 32 is supplied as treated water; the filter 33 ; the activated carbon device (ACF) 34 ; the ion exchange device 35 ; and the reverse osmosis membrane device (RO) 36 . As the processing apparatus 10, for example, the processing apparatus 10 shown in FIG. 1 or FIG. 2 is used. The filter 33, the activated carbon device 34, and the ion exchange device 35 are connected to the outlet of the processing device 10 in this order. The ion exchange device 35 is provided with a cation exchange resin column (CER), a decarboxylation column (DG), and an anion exchange resin column (AER) from its inlet side. The water discharged from the ion exchange device 35 is supplied to the heat exchanger 31 on the upstream side and used as a heat source for raising the temperature of the raw water, and then is supplied to the reverse osmosis membrane device 36 . From the reverse osmosis membrane device 36, primary pure water is discharged. In the final analysis, the pure water production system shown in FIG. 3 is provided with the treatment device 10 as a pre-condition for the pure water production device constituted by the filter 33 , the activated carbon device 34 , the ion exchange device 35 and the reverse osmosis membrane device 36 . processing device. Of course, the configuration of the pure water production apparatus provided in the subsequent stage of the treatment apparatus 10 is not limited to that shown in FIG. 3 .

The heat exchangers 31 and 32 will be described. As can be seen from the examples described later, the decomposition reaction of urea promoted by hypobromous acid will proceed faster only when the reaction temperature is increased. Therefore, the heat exchangers 31 and 32 are installed to warm the water to be treated. To the heat exchanger 31 on the upstream side, the water discharged from the ion exchange device 35 is supplied as a heat source. The water discharged from the ion exchange device 35 is the water obtained by passing the treated water from the treatment device 10 through the filter 33, the activated carbon device 34 and the ion exchange device 35; Although the temperature is raised, it is difficult to raise the temperature of the water to be treated to be supplied to the treatment device 10 to a predetermined temperature by this alone. In view of this, the heat medium from a higher temperature heat source is supplied to the heat exchanger 32 on the downstream side, thereby raising the temperature of the raw water supplied to the treatment device 10 as the water to be treated to a predetermined temperature.

In the pure water production system shown in FIG. 3, although the water discharged from the ion exchange device 35 and supplied to the reverse osmosis membrane device 36 is supplied to the heat exchanger 31 as a heat source; Which part of the pure water production apparatus provided in the subsequent stage of the treatment apparatus 10 is supplied with water to the heat exchanger 31 can be determined according to the configuration of the pure water production apparatus and the like. For example, when the pure water production apparatus is provided with an activated carbon device, as long as the water flowing in the latter stage of the activated carbon device is supplied to the heat exchanger 31, the water supplied to the activated carbon device will be It has been heated, so it can improve the activity of biological activated carbon. Conversely, when the water flowing in the earlier stage of the activated carbon device is supplied to the heat exchanger 31, since the temperature of the water at the inlet of the activated carbon device is lowered, the amount of adsorption in the activated carbon device can be increased. increase. When a coagulation tank is provided in the pure water production apparatus, the coagulation failure due to low water temperature can be suppressed by supplying the heated water discharged from the processing apparatus 10 to the coagulation tank.

In a pure water production apparatus that produces pure water from raw water, a water tank for temporarily storing raw water is generally disposed at the inlet portion to smooth the amount of raw water supplied to the pure water production apparatus. In the pure water production system shown in FIG. 3, since the reaction tank 20 in the processing device 10 also functions as a water tank for temporarily storing raw water, there is no need to provide a separate water tank for temporarily storing raw water.

The configuration in which the water to be treated is heated by a heat exchanger at the inlet of the treatment device 10 is also effective when the treatment device 10 is used alone instead of as a pretreatment device in a pure water production system. In this case, in the treatment apparatus 10, a heat exchanger 31 for heating the water to be treated by the heat recovered from the treated water is provided in the piping for supplying the water to be treated to the plurality of reaction tanks 20, and further On the downstream side of the heat exchanger 31, the heat exchanger 32 on the higher temperature side may be provided. [Example]

The present invention will be described in further detail below by way of Examples and Comparative Examples.

[Example 1] The processing apparatus 10 shown in FIG. 1 is assembled. The number of the reaction tanks 20 arranged in parallel was set to three. Water with a urea concentration of 100 ppb was used as the water to be treated, and a urea decomposer was added and mixed to the water to be treated to the inlet piping 21 so that the concentration of sodium bromide and the concentration of sodium hypochlorite in the water to be treated were 3 ppm and 3.5 ppm. The water to be treated with the urea decomposer added in this way was supplied to one reaction tank 20, and the decomposition reaction of urea was carried out under the conditions of pH 6.0 and temperature of 22°C, and after 2.3 hours, the reaction tank 20 The urea concentration of the water in the middle becomes less than 1ppb. Furthermore, three reaction tanks 20 are used to perform the receiving of the water to be treated, the progress of the decomposition reaction of urea, and the discharge of the treated water in turns, so that the treated water can be continuously received and the treated water can be continuously discharged. At this time, the hydraulic retention time (HRT) in the entire processing apparatus 10 including the three reaction tanks 20 was 6.9 hours.

[Example 2] The processing device 10 shown in FIG. 2 is assembled. However, the number of the reaction tanks 20 arranged in series was set to four. The most upstream reaction tank 20 was supplied with water to be treated containing 100 ppb of urea; to each reaction tank 20, a urea decomposer was added so that the sodium bromide concentration in the water in the reaction tank 20 became 3 ppm and the sodium hypochlorite concentration becomes 3.5ppm. Urea was decomposed so that the pH value in each reaction tank 20 was 6.0, the temperature was 22°C, and the hydraulic retention time of the four reaction tanks 20 as a whole was 5 hours, and then discharged from the most downstream reaction tank 20 The urea concentration in the treated water becomes less than 1ppb.

[Example 3] The same treatment device 10 as in Example 1 was used, and water with a urea concentration of 100 ppb was used as the water to be treated. For the inlet piping 21, a urea decomposer was added and mixed with the water to be treated so that the concentration of sodium bromide in the water to be treated became 3 ppm, and the sodium hypochlorite concentration was 2.4 ppm. The water to be treated with the urea decomposer added in this way is heated to 25° C. and supplied to one reaction tank 20; after that, the decomposition reaction of urea is carried out under the condition of pH 6.0, and after 3 hours have passed , the urea concentration of the water in the reaction tank 20 becomes less than 1 ppb. The heating of the water to be treated is performed by installing a heat exchanger in the inlet pipe 21 and flowing a heat medium through the heat exchanger.

[Comparative Example 1] The tortuous flow reaction tank 40 with 8 wall plate compartments shown in the top view shown in FIG. 4 was assembled. Water with a urea concentration of 100 ppb was used as the water to be treated, and a urea decomposer was added and mixed to the water to be treated so that the concentration of sodium bromide and the concentration of sodium hypochlorite in the water to be treated were 3 ppm and 3.5 ppm. The water to be treated to which the urea decomposer was added in this way was passed through the reaction tank 40, and the decomposition reaction of urea was carried out under the conditions of pH 6.0 and temperature of 22°C. The result of dividing the volume of the reaction tank 40 by the supply flow rate of the water to be treated is regarded as the residence time RT, and after the water to be treated is supplied to the reaction tank 40 and the RT is set to 5 hours, the process of discharging from the reaction tank 40 when a steady state is reached The urea concentration of water is 6ppb. When RT was set to 7 hours, the urea concentration of the treated water discharged from the reaction tank 40 when the steady state was reached was 2 ppb. When RT was set to 8 hours, the urea concentration of the treated water discharged from the reaction tank 40 at the steady state was less than 1 ppb.

Comparing Examples 1, 2 and Comparative Example 1, the conditions for the decomposition reaction of urea are all the same as pH 6 and temperature of 22°C, and the concentration of the urea decomposer is also the same; HRT and RT until the urea concentration in the treated water as a whole is less than 1 ppb, in Example 1, HRT was 6.9 hours, in Example 2, HRT was 5 hours; On the other hand, in Comparative Example 1, RT was 8.5 hours . A long HRT or RT means that the residence time in the reaction tank is that long. If the flow rate of the treated water is the same, the longer the residence time is, the larger the overall volume of the reaction tank will arise. Therefore, it is known that the present invention can reduce the overall reaction tank volume of the treatment device in a treatment device for urea decomposition. .

[Example 4] Urea decomposition was carried out in the same manner as in Example 3, except that the water to be treated was not heated but the decomposition reaction of urea was carried out at a temperature of 10°C. As a result, after 12 hours, the urea concentration of the water in the reaction tank 20 was less than 1 ppb. Although the time required for the decomposition reaction of urea is longer than that in Example 3, it can be considered that this is due to the low reaction temperature. It can be seen that the decomposition reaction of urea can be accelerated by heating. That is, in the processing apparatuses 10 of the first and second embodiments, by disposing the heat exchanger in the inlet piping 21 to warm the water to be treated, it can be seen that even if the residence time is made shorter, the Even if the volume of the reaction tank 20 is further reduced, the urea can still be decomposed to a sufficiently low urea concentration.

10: Processing device 20,40: Reaction tank 21: Inlet piping 22: In-line mixer 23,24: Valve 25: Outlet piping 31, 32: Heat Exchangers 33: Filter 34: Activated carbon device 35: Ion exchange device 36: reverse osmosis membrane device

[ Fig. 1] Fig. 1 is a diagram showing a processing apparatus according to a first embodiment of the present invention. [ Fig. 2] Fig. 2 is a diagram showing a processing apparatus according to a second embodiment of the present invention. [ Fig. 3] Fig. 3 is a schematic diagram showing an example of a pure water production system. [ Fig. 4] Fig. 4 is a schematic diagram illustrating a processing device of Comparative Example 1. [Fig.

10: Processing device

20: Reaction tank

21: Inlet piping

22: In-line mixer

23,24: Valve

25: Outlet piping

Claims (13)

A treatment device that receives the water to be treated, decomposes the urea contained in the water to be treated, and discharges the treated water; the treatment device includes: adding means for adding bromide salt and hypochlorite to the treated water as a urea decomposer; and A plurality of reaction tanks are used to carry out the decomposition reaction of urea with the urea decomposition agent. The processing apparatus of claim 1, wherein, The plurality of reaction tanks are arranged in series, and each of the reaction tanks is provided with the adding means. The processing apparatus of claim 1, wherein, The plurality of reaction tanks are arranged in parallel, and the water to be treated is distributed to the plurality of reaction tanks from the inlet piping shared by the plurality of reaction tanks; While receiving the treated water in at least one of the reaction tanks, discharge the treated water from at least one of the reaction tanks other than the reaction tank that received the treated water; Once the decomposition reaction is completed in the reaction tank receiving the treated water, the treated water is discharged from the reaction tank; The reaction tank that completes the discharge of the treated water is then used for the reception of the treated water. The processing apparatus of claim 3, wherein, The inlet pipe is provided with the adding means, and the inlet pipe is also provided with a mechanism for making the concentration of the urea decomposer in the water to be treated uniform. The processing device of any one of claims 1 to 3, wherein, Each of the plurality of reaction tanks is provided with a stirring mechanism. The processing device of any one of claims 1 to 4, wherein, The hypochlorite is sodium hypochlorite, and the bromide salt is sodium bromide. The processing device of claim 5, wherein, The hypochlorite is sodium hypochlorite, and the bromide salt is sodium bromide. The processing device of any one of claims 1 to 4, wherein, The piping for supplying the water to be treated to the plurality of reaction tanks is provided with a heat exchanger for heating the water to be treated by the heat recovered from the treated water. The processing device of claim 5, wherein, The piping for supplying the water to be treated to the plurality of reaction tanks is provided with a heat exchanger for heating the water to be treated by the heat recovered from the treated water. A pure water production system, comprising at least: an ion exchange device and a reverse osmosis device to which the water passing through the ion exchange device is supplied; The pure water manufacturing system further includes: The processing device according to any one of claims 1 to 4 is used as a preprocessing device. A pure water production system, comprising at least: an ion exchange device and a reverse osmosis device to which the water passing through the ion exchange device is supplied; The pure water manufacturing system further includes: The processing device as claimed in item 5 is used as a preprocessing device. A pure water production system, comprising at least: an ion exchange device and a reverse osmosis device to which the water passing through the ion exchange device is supplied; The pure water manufacturing system further includes: The treatment device of claim 8 is used as a pretreatment device, and the water after passing through the ion exchange device and before being supplied to the reverse osmosis device is supplied to the heat exchanger as a pretreatment device for the treated water. warm heat source. A pure water production system, comprising at least: an ion exchange device and a reverse osmosis device to which the water passing through the ion exchange device is supplied; The pure water manufacturing system further includes: The treatment device of claim 9 is used as a pretreatment device, and the water after passing through the ion exchange device and before being supplied to the reverse osmosis device is supplied to the heat exchanger as a pretreatment device for the treated water. warm heat source.

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