Neutralization treatment system and neutralization treatment method

Abstract

To perform accurate and efficient neutralization of alkaline water to be treated.SOLUTION: A neutralization treatment system 20 neutralizes alkaline water to be treated. The neutralization treatment system 20 includes a distribution route 21 through which the water to be treated can be distributed, a pH measuring unit 2a installed in the distribution route 21 to measure pH of the water to be treated, a turbidity measuring unit 2b installed in the distribution route 21 to measure the degree of turbidity of the water to be treated, and a neutralizer addition unit 5b installed downstream from the pH measuring unit 2a and the turbidity measuring unit 2b in the distribution route 21 and adds a neutralizer to the water to be treated, and an adding amount setting unit 12 which sets the amount of neutralizer added to the water to be treated in the neutralizer adding unit 5b based on the pH and turbidity of the water to be treated as measured in the pH measuring unit 2a and the turbidity measuring unit 2b.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD

[0001] The present invention relates to a system and a method for neutralizing alkaline water to be treated. BACKGROUND ART

[0002] Patent Document 1 discloses that neutralization is performed by injecting carbon dioxide into construction waste liquid when the waste liquid generated at construction sites such as dams and tunnels or large-scale construction works is treated so that it can be discharged into rivers or the like. PRIOR ART DOCUMENT PATENT DOCUMENT

[0003] Patent Document 1 Japanese Unexamined Patent Publication No. 2001-9473 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0004] However, in the technology disclosed in Patent Document 1, the pH of the construction waste liquid after carbon dioxide is injected (that is, the construction waste liquid after neutralization) is measured with a pH sensor, and the injection amount of carbon dioxide into the construction waste liquid can be adjusted based on the measurement result. That is, in the technology disclosed in Patent Document 1, since the pH measurement of the construction waste liquid by the pH sensor is performed after the neutralization treatment, the adjustment of the aforementioned injection amount is done after the fact. Further, even if the aforementioned injection amount is set based only on the measurement result of the pH sensor, the value often deviates from the actual injection amount of carbon dioxide required for the neutralization treatment.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to perform neutralization treatment accurately and efficiently. MEANS FOR SOLVING THE PROBLEM

[0006] Therefore, the neutralization treatment system according to the present invention is a system for neutralizing alkaline water to be treated. The neutralization treatment system according to the present invention comprises a distribution path through which treated water can flow, a pH measuring unit provided in the distribution path for measuring the pH of the water to be treated, a turbidity measuring unit provided in the distribution path for measuring the degree of turbidity of the water to be treated, a neutralizing agent adding unit provided downstream of the pH measuring unit and downstream of the turbidity measuring unit in the distribution path for adding a neutralizing agent to the water to be treated, and an addition amount setting unit that sets the amount of neutralizing agent to be added to the water to be treated in the neutralizing agent adding unit based on the measured pH and degree of turbidity.

[0007] The neutralization treatment method according to the present invention is a method of neutralizing water to be treated by adding a neutralizing agent to alkaline water to be treated. The neutralization treatment method according to the present invention includes measuring the pH and turbidity of the water to be treated before the neutralizing agent is added, and setting the amount of neutralizing agent to be added to the water to be treated based on the measured pH and turbidity.

[0008] In this context, "measuring the degree of turbidity of the water to be treated" in the present invention may include measuring the turbidity of the water to be treated, or measuring the amount of suspended solids (SS) contained in the water to be treated (e.g., SS concentration). [Effects of the Invention]

[0009] According to the present invention, when neutralizing water to be treated, by measuring not only the pH of the water to be treated but also the degree of turbidity of the water to be treated, the neutralization treatment can be performed accurately and efficiently. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows the schematic configuration of a turbid water treatment system including a neutralization treatment system in the first embodiment of the present invention. [Figure 2] Flowchart showing the neutralization treatment method in the above embodiment [Figure 3]Table showing the relationship between pH and SS concentration of turbid water and CO2 addition amount in the above embodiment. [Figure 4] Table showing the relationship between the SS concentration of turbid water and the required injection ratio in the above embodiment. [Figure 5] A flowchart illustrating the method for setting the amount of neutralizing agent to be added in the second embodiment of the present invention. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings.

[0012] Figure 1 shows a schematic configuration of a turbid water treatment system 1 including a neutralization treatment system 20 in a first embodiment of the present invention. The turbid water treatment system 1 is a system for treating wastewater generated at, for example, civil engineering or construction sites to meet discharge control limits before discharging it into rivers or other bodies of water. The wastewater generated at these construction sites is, for example, alkaline turbid water (mud water) and may contain, for example, cement and / or bentonite.

[0013] The turbid water treatment system 1 comprises a raw water tank 2, a coagulation tank 3, and a discharge tank 4. The raw water tank 2 and the coagulation tank 3 are connected by piping 5. The coagulation tank 3 and the discharge tank 4 are connected by piping 6.

[0014] The aforementioned turbid water is stored in the raw water tank 2. The turbid water (raw water) stored in the raw water tank 2 is sent to the piping 5 by a pump (not shown) or the like. The piping 5 is equipped with a flow meter 5a for measuring the flow rate of the turbid water flowing through the piping 5. The flow meter 5a is, for example, an electromagnetic flow meter.

[0015] In the present embodiment, a neutralizing agent adding portion 5b, an inorganic flocculant adding portion 5c, and a polymer flocculant adding portion 5d are provided in the pipe 5 in order from the upstream side to the downstream side. A downstream end of a neutralizing agent supply pipe 7 is connected to the neutralizing agent adding portion 5b, and in the neutralizing agent adding portion 5b, an acidic neutralizing agent for neutralizing turbid water is added to the turbid water. A downstream end of an inorganic flocculant supply pipe 8 is connected to the inorganic flocculant adding portion 5c, and in the inorganic flocculant adding portion 5c, an inorganic flocculant such as polyaluminum chloride (PAC) is added to the turbid water. A downstream end of a polymer flocculant supply pipe 9 is connected to the polymer flocculant adding portion 5d, and in the polymer flocculant adding portion 5d, a polymer flocculant is added to the turbid water.

[0016] Here, the aforementioned flocculant has a function of aggregating fine particles in turbid water into flocs. In the present embodiment, both an inorganic flocculant and a polymer flocculant are used as the aforementioned flocculant, but alternatively, either one of these flocculants may be used. In the present embodiment, carbon dioxide (CO2) is used as the aforementioned neutralizing agent, but alternatively, dilute sulfuric acid may be used as the neutralizing agent.

[0017] In the present embodiment, the neutralizing agent adding portion 5b, the inorganic flocculant adding portion 5c, and the polymer flocculant adding portion 5d may be configured to include, for example, a line mixer. In the neutralizing agent adding portion 5b, the neutralizing agent from the neutralizing agent supply pipe 7 is injected into and mixed with the turbid water; in the inorganic flocculant adding portion 5c, the inorganic flocculant from the inorganic flocculant supply pipe 8 is injected into and mixed with the turbid water; and in the polymer flocculant adding portion 5d, the polymer flocculant from the polymer flocculant supply pipe 9 can be injected into and mixed with the turbid water.

[0018] Note that in the present embodiment, the neutralizing agent adding portion 5b, the inorganic flocculant adding portion 5c, and the polymer flocculant adding portion 5d are arranged in this order in the pipe 5 from the upstream side to the downstream side, but the arrangement order of the neutralizing agent adding portion 5b, the inorganic flocculant adding portion 5c, and the polymer flocculant adding portion 5d is not limited thereto. For example, in the pipe 5, the inorganic flocculant adding portion 5c, the polymer flocculant adding portion 5d, and the neutralizing agent adding portion 5b may be arranged in this order from the upstream side to the downstream side.

[0019] Here, the turbid water described above corresponds to an example of the "water to be treated" in the present invention. This "water to be treated" may contain cement and / or bentonite.

[0020] In the coagulation tank 3, the aforementioned flocs and the like are precipitated, and the supernatant thereof is delivered to the pipe 6 by a pump or the like (not shown) and stored in the discharge tank 4. The water stored in the discharge tank 4 (hereinafter referred to as "treated water") is discharged to a river or the like after it is confirmed that the water has been treated so as to satisfy the discharge control values. Note that, in order to confirm that the treated water has been treated so as to satisfy the discharge control values, measuring means such as a pH meter and a turbidimeter (not shown) may be provided in the discharge tank 4. Further, measuring means such as a pH meter and a turbidimeter may also be provided in the coagulation tank 3.

[0021] The neutralization treatment system 20 constitutes the turbid water treatment system 1. Further, the neutralization treatment system 20 neutralizes turbid water by adding an acidic neutralizing agent to alkaline turbid water. Note that the "neutralization treatment" in the present embodiment means, for example, a treatment in which the target value of the treatment is set to about pH 7 to 7.5, and an acidic neutralizing agent is added to alkaline turbid water to neutralize the same.

[0022] The neutralization treatment system 20 includes, as a flow passage 21 through which turbid water can flow, the aforementioned raw water tank 2 and the pipe 5 in order from the upstream side toward the downstream side. That is, the flow passage 21 includes the raw water tank 2 and the pipe 5.

[0023] The neutralization treatment system 20 includes a pH measuring unit 2a for measuring the pH of the turbid water and a turbidity measuring unit 2b for measuring the degree of turbidity of the turbid water. The "degree of turbidity of the turbid water" measured by the turbidity measuring unit 2b may include either the "turbidity of the turbid water" or the "amount of suspended solids (SS) contained in the turbid water (e.g., SS concentration)". If the "degree of turbidity of the turbid water" measured by the turbidity measuring unit 2b is the "turbidity of the turbid water", a turbidity measuring means such as a turbidimeter may be used. If the "degree of turbidity of the turbid water" measured by the turbidity measuring unit 2b is the "amount of SS contained in the turbid water (e.g., SS concentration)", a suspended solids amount measuring means such as an SS meter (e.g., SS concentration meter) may be used.

[0024] In this embodiment, the pH measuring unit 2a and the turbidity measuring unit 2b are provided in the raw water tank 2, but the pH measuring unit 2a and the turbidity measuring unit 2b can be installed at any location upstream of the neutralizing agent addition unit 5b in the flow path 21. Furthermore, the neutralizing agent addition unit 5b is provided downstream of the pH measuring unit 2a and downstream of the turbidity measuring unit 2b in the flow path 21.

[0025] The neutralization treatment system 20 comprises a neutralizing agent addition section 5b and a neutralizing agent supply pipe 7, and a storage section 10 that contains the neutralizing agent supplied to the neutralizing agent supply pipe 7. In this embodiment, since CO2 is used as the neutralizing agent, the storage section 10 may be composed of, for example, a plurality of cylinders that contain CO2.

[0026] The neutralizing agent supply piping 7 is equipped with a flow meter 7a for measuring the flow rate of the neutralizing agent flowing through the neutralizing agent supply piping 7, and a flow control valve 7b for adjusting the flow rate of the neutralizing agent flowing through the neutralizing agent supply piping 7. In this embodiment, the flow meter 7a and the flow control valve 7b are provided separately as devices in the neutralizing agent supply piping 7, but in addition, a mass flow controller (MFC) equipped with a flow meter 7a and a flow control valve 7b may also be provided in the neutralizing agent supply piping 7.

[0027] The neutralization treatment system 20 includes a control unit 11 for controlling the neutralization treatment of turbid water. The control unit 11 is configured to receive information regarding the pH measurement of the turbid water from the pH measuring unit 2a and information regarding the turbidity level measurement of the turbid water from the turbidity level measuring unit 2b via wired or wireless communication. The control unit 11 is configured to receive information regarding the flow rate measurement of the turbid water from the flow meter 5a via wired or wireless communication. The control unit 11 is configured to receive information regarding the flow rate measurement of the neutralizing agent from the flow meter 7a via wired or wireless communication. The control unit 11 is configured to transmit instruction information for the valve opening degree of the flow control valve 7b to the flow control valve 7b via wired or wireless communication.

[0028] The control unit 11 includes an additive amount setting unit 12 for setting the amount of neutralizing agent to be added to the turbid water. The additive amount setting unit 12 includes a processing unit 12a for performing various processing for setting the additive amount, and a storage unit 12b for storing various data (including the tables shown in Figures 3 and 4 described later) that can be used for these various processing.

[0029] Figure 2 is a flowchart showing a neutralization process that can be implemented by the control unit 11.

[0030] In step S1, the pH of the turbid water is measured in the pH measuring unit 2a, and the degree of turbidity of the turbid water is measured in the turbidity measuring unit 2b. These measurements may be taken simultaneously or with a slight delay between them.

[0031] Next, in step S2, based on the pH measurement and the turbidity level measurement of the turbid water obtained in step S1, the amount of neutralizing agent to be added to the turbid water necessary for neutralization is determined.

[0032] Here, an example of how to set the amount of neutralizing agent to be added in step S2 will be explained using Figure 3, in addition to Figures 1 and 2 mentioned above.

[0033] Figure 3 is a table showing the relationship between the pH of turbid water, the SS concentration of the turbid water (an example of the degree of turbidity), and the amount of CO2 added to the turbid water (hereinafter referred to as "CO2 addition amount"), which is an example of a neutralizing agent. This table was obtained in advance by conducting experiments in which samples were prepared for each variation of turbid water that may occur at a construction site and neutralized each sample, and is stored in the aforementioned memory unit 12b. This table shows that when the pH of the turbid water is approximately the same (approximately constant), the higher the SS concentration of the turbid water, the greater the amount of CO2 added. Note that the SS concentration of the turbid water in this table may be obtained by converting turbidity (units such as "degrees" or "NTU") that can be measured by a turbidimeter to SS concentration (units such as "ppm" or "mg / liter"). This conversion formula can also be obtained in advance by conducting the aforementioned experiments.

[0034] In step S2, the measured pH of the turbid water and the measured SS concentration of the turbid water (including the turbidity of the measured turbid water converted to SS concentration as described above) obtained in step S1 are applied to the table shown in Figure 3 to set the amount of CO2 to be added (amount of CO2 to be added per liter of turbid water). For example, referring to Figure 3, if the measured pH of the turbid water is 10 and the measured SS concentration of the turbid water is 6000 ppm, then the amount of CO2 to be added is set to 0.01496 g / liter. It goes without saying that well-known methods (e.g., linear interpolation, Lagrangian interpolation, spline interpolation, etc.) may be used to interpolate the finite number of discrete data points that make up the table shown in Figure 3. In this way, step S2 sets the amount of neutralizing agent needed to be added to the turbid water in order to neutralize it.

[0035] Next, in step S3, the addition of the neutralizing agent to the turbid water is controlled by controlling the valve opening of the flow control valve 7b so that the amount of neutralizing agent to be added to the turbid water is the same as the amount set in step S2. In this control, the target flow rate of the neutralizing agent is calculated based on the amount of neutralizing agent to be added to the turbid water set in step S2 and the flow rate of the turbid water measured by the flow meter 5a. The valve opening of the flow control valve 7b is then controlled to achieve this target flow rate while monitoring the flow rate of the neutralizing agent with the flow meter 7a. In this way, feedforward control of the neutralization treatment for turbid water is implemented.

[0036] Next, an example of how to create the table shown in Figure 3 will be explained using Figure 4. Figure 4 is a table showing the relationship between the SS concentration in turbid water and the required injection ratio.

[0037] When creating the table shown in Figure 3, first, the reference value α for the amount of CO2 added is calculated. This reference value α is the amount of CO2 added to bring the alkaline turbid water to the target pH (target pH = 7 in this embodiment). For example, the following equation (1) can be used to calculate this reference value α.

[0038] α [g / liter] = 44 × 10 -(14-n) ...(1)

[0039] In equation (1), "44" on the right side represents the molecular weight of CO2, and "n" represents the pH of the turbid water.

[0040] Next, by applying the table showing the relationship between the SS concentration of turbid water and the required injection ratio β, as shown in Figure 4, to the aforementioned calculated reference value α (specifically, by calculating α × β for each SS concentration of turbid water), the table shown in Figure 3 is created.

[0041] For example, regarding the case of turbid water with a pH of 10 in the table shown in Figure 3, first, the aforementioned reference value α is calculated as follows using the aforementioned formula (1). α = 44 × 10 -(14-10) = 44 × 10 -4 =0.0044 [g / liter] If the SS concentration of the turbid water is 3000 ppm, then as shown in Figure 4, the predetermined injection ratio β is 1.8. Therefore, if the pH of the turbid water is 10 and the SS concentration of the turbid water is 3000 ppm, the amount of CO2 to be added is: α × β = 0.0044 × 1.8 = 0.00792 [g / liter] This is the result. If the SS concentration of the turbid water is 6000 ppm, then as shown in Figure 4, the predetermined injection ratio β is 3.4. Therefore, if the pH of the turbid water is 10 and the SS concentration of the turbid water is 6000 ppm, the amount of CO2 to be added is: α × β = 0.0044 × 3.4 = 0.01496 [g / liter] This is the result. If the SS concentration of the turbid water is 12000 ppm, then as shown in Figure 4, the predetermined injection ratio β is 3.5. Therefore, if the pH of the turbid water is 10 and the SS concentration of the turbid water is 12000 ppm, the amount of CO2 to be added is: α × β = 0.0044 × 3.5 = 0.01540 [g / liter] This is the result. The same calculation is performed for cases where the pH of the turbid water is other than 10, resulting in the table shown in Figure 3.

[0042] Herein, the tables shown in Figures 3 and 4 were obtained in advance by conducting experiments in which samples were prepared for each variation of turbid water that may occur at a construction site and neutralized each sample, and were discovered by the inventors. The table in Figure 3 shows that when the pH of the turbid water is approximately the same (approximately constant), the higher the SS concentration of the turbid water, the greater the amount of CO2 to be added. The table in Figure 4 shows that the higher the SS concentration of the turbid water, the higher the required injection ratio β. These are new findings discovered by the inventors.

[0043] Furthermore, in step S2 described above, the addition amount setting unit 12 can refer to the table shown in Figure 3 and set the amount of CO2 to be added such that, when the pH of the turbid water measured by the pH measurement unit 2a is approximately the same (approximately constant), the amount of CO2 added increases as the SS concentration of the turbid water measured by the turbidity measurement unit 2b increases.

[0044] This invention is based on a novel finding discovered by the inventors that by measuring the degree of turbidity of turbid water generated at construction sites and the like, it is possible to easily grasp the content of interfering components (buffering components) that reduce the effectiveness of neutralizing agents in said turbid water. This invention has the exceptional effect of allowing the measurement results to be utilized for feedforward control of the neutralization treatment of said turbid water.

[0045] According to this embodiment, the neutralization treatment system 20 is a system for neutralizing alkaline water to be treated (e.g., turbid water). The neutralization treatment system 20 includes a flow path 21 through which the water to be treated can flow, a pH measuring unit 2a provided in the flow path 21 for measuring the pH of the water to be treated, a turbidity measuring unit 2b provided in the flow path 21 for measuring the degree of turbidity of the water to be treated, a neutralizing agent adding unit 5b provided downstream of the pH measuring unit 2a and downstream of the turbidity measuring unit 2b in the flow path 21 for adding a neutralizing agent (e.g., CO2) to the water to be treated, and an addition amount setting unit 12 that sets the amount of neutralizing agent to be added to the water to be treated in the neutralizing agent adding unit 5b based on the pH and turbidity of the water to be treated measured by the pH measuring unit 2a and the turbidity measuring unit 2b. Therefore, when neutralizing the water to be treated, measuring not only the pH of the water but also the degree of turbidity of the water to be treated allows for accurate and efficient feedforward control of the neutralization process.

[0046] Furthermore, according to this embodiment, the addition amount setting unit 12 has a table (see Figure 3) that associates the pH and turbidity of the water to be treated (e.g., turbid water) with the amount of neutralizing agent (e.g., CO2) to be added to the water to be treated. The addition amount setting unit 12 sets the amount of neutralizing agent to be added to the water to be treated based on the pH and turbidity of the water to be treated measured by the pH measurement unit 2a and the turbidity measurement unit 2b, and the table (see Figure 3) (see step S2 in Figure 2). This table (see Figure 3) is arranged such that, when the pH of the water to be treated is approximately the same (approximately constant), the amount added increases as the turbidity of the water to be treated increases. The amount added can be easily set using this table (see Figure 3).

[0047] Furthermore, according to this embodiment, the addition amount setting unit 12 sets the addition amount such that the higher the turbidity of the water to be treated (e.g., turbid water) measured by the turbidity measurement unit 2b, the greater the amount of neutralizing agent (e.g., CO2) added to the water to be treated. This allows the setting value to be quickly changed in response to changes in the turbidity of the water to be treated, and this can be reflected in the feedforward control of the neutralization treatment of the water to be treated.

[0048] The additive amount setting unit 12 has a table (see Figure 4) that associates the degree of turbidity of the water to be treated (e.g., turbid water) with the required injection ratio β. This table (see Figure 4) is arranged so that the required injection ratio β increases as the degree of turbidity of the water to be treated increases. This is a new finding discovered by the inventors.

[0049] Furthermore, according to this embodiment, the neutralization treatment method is a method of neutralizing water to be treated by adding a neutralizing agent (e.g., CO2) to alkaline water to be treated (e.g., turbid water). This neutralization treatment method includes measuring the pH and turbidity of the water to be treated before the neutralizing agent is added (see step S1 in Figure 2), and setting the amount of neutralizing agent to be added to the water to be treated based on the measured pH and turbidity (see step S2 in Figure 2). Therefore, when neutralizing water to be treated, by measuring not only the pH of the water to be treated but also the degree of turbidity of the water to be treated, it is possible to achieve accurate and efficient feedforward control of the neutralization treatment.

[0050] Next, a second embodiment of the present invention will be described with reference to Figure 5. Figure 5 is a flowchart showing the method for setting the amount of neutralizing agent to be added in this embodiment. The differences from the first embodiment described above will now be explained.

[0051] In this embodiment, the method for setting the amount of neutralizing agent to be added, as shown in Figure 5, can be carried out in step S2 of Figure 2 described above. In this embodiment as well, CO2 is used as an example of a neutralizing agent, but the neutralizing agent is not limited to CO2; for example, dilute sulfuric acid may also be used.

[0052] In step S11, the reference value α for the amount of CO2 added is determined based on the pH of the turbid water measured by the pH measuring unit 2a (i.e., the measured value of the pH of the turbid water) (first step). For example, the result of calculating the reference value α using the formula (1) described above is used to determine this reference value α.

[0053] Next, in step S12, the aforementioned standard value α for the amount of CO2 added is corrected based on the degree of turbidity of the turbid water measured by the turbidity measurement unit 2b (i.e., the measured value of the degree of turbidity of the turbid water), and in step S13, the result of this correction is determined as the aforementioned set value for the amount of CO2 added (second step).

[0054] Here, an example of the processing in steps S12 and S13 will be explained using Figure 4 mentioned above.

[0055] In step S12, the required injection ratio β corresponding to the measured SS concentration, which is an example of the degree of turbidity in the turbid water, is obtained by applying the measured value of SS concentration to the table shown in Figure 4. This obtained required injection ratio β is then applied to the standard value α of the CO2 addition amount determined in step S11 (specifically, by calculating α × β), thereby correcting the standard value α of the CO2 addition amount. Since Figure 4 is used in this step, the correction may be made so that the higher the measured value of SS concentration, the higher the set value of the CO2 addition amount. In step S13, this correction result (i.e., the aforementioned α × β) is determined as the set value for the CO2 addition amount.

[0056] It goes without saying that well-known methods (e.g., linear interpolation, Lagrangian interpolation, spline interpolation, etc.) may be used to interpolate the finite number of discrete data points that make up the table shown in Figure 4.

[0057] In particular, according to this embodiment, in the neutralization treatment method, setting the amount of neutralizing agent (e.g., CO2) to be added to the water to be treated (e.g., turbid water) (see step S2 in Figure 2) includes a first step (see step S11 in Figure 5) of determining a reference value α for the amount to be added based on the measured pH, and a second step (see steps S12, S13 in Figure 5) of correcting the reference value α for the amount to be added based on the measured degree of turbidity and determining the result as the set value for the amount to be added. The second step includes performing the correction so that the set value for the amount to be added increases as the measured degree of turbidity increases. Therefore, the creation of the table shown in Figure 3 above can be omitted, and the burden on the storage unit 12b can be reduced accordingly.

[0058] In the first and second embodiments described above, the aforementioned formula (1) was used to calculate the reference value α for the amount of CO2 added. Alternatively, the following formula (2) may be used to calculate the reference value α.

[0059] α [g / liter] = 44 × {10 -(14-n) -10 -(14-m)} …(2)

[0060] In equation (2), "44" and "n" on the right-hand side are the same as in equation (1) above, and "m" on the right-hand side is the target pH for the neutralization treatment. This target pH may be in the range of 7 to 7.5, for example.

[0061] In the first and second embodiments described above, wastewater generated at construction sites was cited as an example of the "water to be treated" of the present invention. However, other examples of the "water to be treated" of the present invention include, for example, wastewater generated at factories that manufacture precast concrete products.

[0062] The illustrated embodiments are merely illustrative of the present invention, and it goes without saying that the present invention includes not only those directly shown by the described embodiments, but also various improvements and modifications made by those skilled in the art within the scope of the claims. [Explanation of Symbols]

[0063] 1. Turbid Water Treatment System 2 Raw water tank 2a pH measuring section 2b Turbidity measurement section 3 Coagulation tank 4 Outlet tank 5 Piping 5a flow meter 5b Neutralizing agent addition section 5c Inorganic flocculant addition section 5d Polymer flocculant added section 6 Piping 7. Neutralizing agent supply piping 7a flow meter 7b Flow control valve 8. Inorganic coagulant supply piping 9. Polymer flocculant supply piping 10 Storage Unit 11 Control Unit 12 Addition amount setting section 12a Processing Unit 12b Storage section 20 Neutralization Treatment System 21 Distribution Channels

Claims

1. A system for neutralizing alkaline water to be treated, A distribution route through which the treated water can be distributed, A pH measuring unit is provided in the aforementioned distribution path to measure the pH of the water to be treated, A turbidity measuring unit is provided in the aforementioned distribution route for measuring the degree of turbidity of the water to be treated, A neutralizing agent addition unit is provided downstream of the pH measuring unit and downstream of the turbidity measuring unit in the aforementioned distribution path, for adding a neutralizing agent to the water to be treated, Based on the measured pH and degree of turbidity, an additive amount setting unit sets the amount of the neutralizing agent to be added to the treated water in the neutralizing agent addition unit, A neutralization treatment system equipped with the following features.

2. The additive amount setting unit has a table in which the pH and turbidity of the water to be treated are associated with the additive amount. The neutralization treatment system according to claim 1, wherein the additive amount setting unit sets the additive amount based on the measured pH and turbidity level and the table.

3. The neutralization treatment system according to claim 1 or claim 2, wherein the additive amount setting unit sets the additive amount such that the amount of additive increases as the measured degree of turbidity increases.

4. A method for neutralizing alkaline water to be treated by adding a neutralizing agent to the water to be treated, The pH and turbidity of the treated water are measured before the neutralizing agent is added. Based on the measured pH and degree of turbidity, the amount of neutralizing agent to be added to the water to be treated is determined. A neutralization method including the following.

5. Setting the aforementioned amount of additive means A first step is to determine a reference value for the amount to be added based on the measured pH, A second step involves correcting the reference value based on the measured degree of turbidity and determining the result as the set value for the amount to be added. The neutralization treatment method according to claim 4, including the method described in claim 4.

6. The neutralization treatment method according to claim 5, wherein the second step includes performing the correction such that the set value of the amount to be added increases as the measured degree of turbidity increases.

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