JP2015184273A - Concentration measuring apparatus and cleaning method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concentration measuring apparatus capable of achieving highly accurate concentration measurement of a heavy metal collector and determining an appropriate additional amount of the same to sewage, and a cleaning method of the concentration measuring apparatus.SOLUTION: A concentration measuring apparatus 1 includes a measuring section 2 configured to automatically measure the concentration of a heavy metal collector in a measuring object liquid contained in a cell, and a controller 3 configured to control the timing when a cleaning agent, capable of removing the pollution derived from the measuring object liquid deposited in the cell, is circulated in the cell.

Description

  The present invention relates to a concentration measuring device used for measuring the concentration of a heavy metal scavenger and a cleaning method for the concentration measuring device. More specifically, the present invention relates to a concentration measuring apparatus that removes dirt from a cell by causing a cleaning agent to flow through the cell at a specific timing, and a cleaning method for the concentration measuring apparatus.

  The drainage may contain heavy metals such as copper, chromium, zinc, lead, manganese, iron, nickel, and cadmium. As a method for treating heavy metal ions contained in the wastewater, a method is known in which a heavy metal scavenger is added to the wastewater to perform a coagulation sedimentation treatment (see, for example, Patent Document 1). In Patent Document 1, a compound having a functional group capable of forming a complex such as dithiocarbamate is cited as a heavy metal scavenger for the coagulation sedimentation treatment.

  When using this heavy metal scavenger, if the amount of heavy metal scavenger added is insufficient relative to the heavy metal in the wastewater, sufficient treatment effect cannot be obtained, while if the amount added is too large, Cost will increase. Therefore, it is necessary to accurately grasp the concentration of the heavy metal scavenger added to the waste water.

  The concentration of the heavy metal scavenger can be grasped, for example, by measuring the absorbance of a solution containing the heavy metal scavenger. In Patent Document 2, a heavy metal ion is reacted with a dithiocarbamic acid-based heavy metal collector to develop a color, and the concentration of the heavy metal collector is measured from the absorbance at a wavelength of 400 to 700 nm. Techniques for controlling are disclosed. According to this technique, it is possible to make the amount of chemical injection of the heavy metal scavenger with respect to the heavy metal-containing wastewater an appropriate amount.

  Moreover, as a method of measuring this absorbance, there are techniques disclosed in Patent Document 3 and Patent Document 4. Patent Document 3 discloses a technique in which a light emitting element is provided on one side and a light receiving element is provided on the other side so as to sandwich a measurement cell. Patent Document 4 discloses a technique for measuring the concentration of a lysate by measuring the absorbance of a liquid to be measured in which a reagent is added to a sample by an apparatus using a reflector. According to this technique, since the reflecting plate is used when measuring the absorbance of the liquid to be measured, the apparatus can be downsized.

JP 2001-340874 A JP 2012-161724 A JP 2006-257553 A JP 2010-181150 A

  However, in the above-described technique, it is necessary to suppress a decrease in measurement accuracy of the concentration of the heavy metal scavenger due to dirt in the cell accumulated by repeatedly measuring the concentration of the heavy metal scavenger. On the other hand, for example, a method of removing dirt in the cell every time measurement is performed can be considered, but this operation is complicated. If the cell dirt could not be removed sufficiently, the concentration of the heavy metal scavenger could not be measured accurately, and the exact amount of heavy metal scavenger added to the wastewater could not be determined.

  Therefore, the present invention realizes highly accurate concentration measurement of a heavy metal scavenger and a concentration measuring device capable of determining an accurate addition amount of the heavy metal scavenger to waste water and a cleaning method for the concentration measuring device The main purpose is to provide

In the present invention, a measurement unit that automatically measures the concentration of the heavy metal scavenger in the measurement target liquid placed in the cell, and a cleaning that can remove the dirt derived from the measurement target liquid that has adhered to the cell And a control unit that controls the timing of flowing the agent into the cell. According to the concentration measuring apparatus of the present invention, dirt adhering to the cell can be automatically removed.
The measurement unit may measure the concentration of the heavy metal scavenger based on the light transmittance of the measurement target liquid.
In the concentration measuring apparatus, the control unit may cause the cleaning agent to flow through the cell when the light transmittance is equal to or lower than a predetermined value.
In the concentration measuring apparatus, the control unit may cause the cleaning agent to flow through the cell when the number of times of measurement of the concentration of the heavy metal scavenger by the measuring unit reaches a predetermined number. .
In the concentration measuring device, the heavy metal scavenger can be a dithiocarbamic acid heavy metal scavenger.
Moreover, the said measuring object liquid may contain the coloring reagent which has a bivalent iron ion.
Furthermore, the cleaning agent may contain at least one selected from oxalic acid, hydrochloric acid, sulfuric acid acidic hydrogen peroxide, hydrofluoric acid, nitric acid, sulfuric acid, citric acid, and a chelating agent. In particular, the cleaning agent may contain oxalic acid or hydrochloric acid. At this time, the oxalic acid may be contained in 3 to 10% by mass in the total amount of the cleaning agent.

  Further, in the present invention, it is possible to automatically measure the concentration of the heavy metal scavenger in the measurement target liquid placed in the cell, and to remove the dirt derived from the measurement target liquid attached in the cell. And a step of cleaning the inside of the cell by allowing a cleaning agent to flow through the cell at a predetermined timing.

  According to the present invention, it is possible to automatically remove the dirt adhering to the cell, so that it is possible to measure the concentration of the heavy metal scavenger with high accuracy and determine the exact amount of the heavy metal scavenger added to the waste water. It becomes possible to do.

By heavy metal scavenger H illustrates a coagulation sedimentation process system 10 for performing coagulation precipitation treatment of heavy metals in the waste water S _0. It is a figure explaining the structure of the density | concentration measuring apparatus 1 of embodiment of this invention. 4 is an exploded perspective view in which a main body 20 and a light emitting / receiving unit 21 of the measurement unit 2 are disassembled. FIG. It is a figure explaining the state of the light emission and light reception which are performed in the measurement part. FIG. 3 is an electrical wiring diagram inside the light emitting / receiving unit 21. It is a flowchart which shows an example of the washing | cleaning method performed with the density | concentration measuring apparatus 1 of this embodiment. It is a flowchart which shows an example of the washing | cleaning method performed with the density | concentration measuring apparatus 1 of this embodiment. It is a figure explaining the structure of the density | concentration measuring apparatus 1 of the modification of this embodiment. It is a graph showing the change of the light transmittance of a measuring object liquid at the time of using various cleaning agents.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below.

FIG. 1 is a diagram illustrating a coagulation sedimentation processing system 10 having a concentration measuring device 1 according to an embodiment of the present invention. Reference numeral 11 denotes a water channel to flow through the drainage _{S 0.} A coagulation tank, a sedimentation basin, etc. (not shown) are laid in the water channel 11. The coagulating sedimentation processing system 10, the waste water S ₀ taken into waterways 11, is added heavy metal scavenger H in the tank 12, not (shown by coagulation precipitation treatment of heavy metals in the waste water S ₀ is performed ), treated water _{S 1} is produced.

  Examples of heavy metals in the waste water S0 include mercury, cadmium, arsenic, lead, hexavalent chromium, selenium, copper, zinc, manganese, divalent iron, nickel, and trivalent iron.

At this time, the amount of heavy metal scavenger is added to the wastewater S _0, it is adjusted by the amount adjustment device 13. Specifically, a part of the treated water S ₁ is extracted, and the concentration measuring device 1 measures the concentration of the heavy metal scavenger H in the treated water S ₁ . Then, depending on the concentration, amount adjusting device 13 adjusts the valve opening and closing condition 14, is possible to adjust the amount of heavy metal scavenger H to be added to the waste water S ₀ through the chemical feed pump P it can. Also, depending on the concentration, amount adjusting device 13, to adjust the timing of the on and off states of the addition of the heavy metal scavenger H, and to adjust the added frequency is added to the waste water S ₀ heavy metals The amount of the collecting agent H can also be adjusted. That is, if higher than the value which the concentration of heavy metal scavenger H was set in advance, the addition amount adjusting device 13 reduces the amount of the waste water S ₀ of a heavy metal scavenger H. On the other hand, lower than the value which the concentration of heavy metal scavenger H was set in advance, the addition amount adjusting device 13, increasing the amount of the waste water S ₀ of a heavy metal scavenger H.

Method of measuring the specific density is not particularly limited, for example, firstly, the addition of coloring reagent X which develops a color by reacting with heavy metal scavenger H in treated water S _1. The concentration of the heavy metal scavenger H is measured by measuring the light transmittance of the measurement target liquid Y thus obtained. In addition, about the measuring object liquid Y by which the density | concentration was measured with the density | concentration measuring apparatus 1, it can dispose by arbitrary methods.

  However, in the concentration measuring apparatus 1, if the cell G (see FIG. 2 described later) into which the liquid Y to be measured is contaminated, an error occurs in the concentration measurement. As a result, the addition amount adjusting apparatus 13 collects heavy metals. The added amount of the agent H cannot be adjusted accurately. As this stain, for example, when a dithiocarbamic acid heavy metal collector is used as the heavy metal collector H and ferrous chloride is used as the coloring reagent X, a dithiocarbamide group and iron chelate can be used. Examples include dirt with a slow decomposition rate.

In contrast, the inventors of the present invention relate to a concentration measuring apparatus 1 that automatically removes dirt adhering to the cell G as a result of intensive studies in the coagulation sedimentation treatment system 10 for the wastewater S ₀ using the heavy metal scavenger H. The present invention has been found and the present invention has been completed. Hereinafter, a specific configuration and function of the concentration measuring apparatus 1 according to the embodiment of the present invention will be described.

<Concentration measuring device 1>
FIG. 2 is a diagram for explaining the configuration of the concentration measuring apparatus 1 of the present embodiment. Concentration measuring apparatus 1 is an apparatus for measuring the concentration of heavy metal scavenger H of treated water S in _1. Specifically, a device for measuring the concentration of a heavy metal scavenger H of treated water S the analyte solution Y color development reagent X was added to _1. And in the density | concentration measuring apparatus 1 of this embodiment, it is possible to remove automatically the stain | pollution | contamination adhering to the cell G derived from the measuring object liquid Y at a predetermined timing.

  The concentration measuring apparatus 1 includes a measuring unit 2 that automatically measures the concentration of the heavy metal scavenger H in the measurement target liquid Y, and a cleaning agent Z that can remove dirt from the measurement target liquid Y attached to the cell. And a control unit 3 that controls the timing of flowing into the cell.

  Further, the concentration measuring apparatus 1 is provided with a measurement liquid supply unit 4 that supplies the measurement target liquid Y to the measurement unit 2 and a cleaning agent supply unit 5 that supplies the cleaning agent Z to the measurement unit 2.

  Further, the concentration measuring apparatus 1 includes a liquid supply line 6 that supplies both the measurement target liquid Y supplied from the measurement liquid supply unit 4 and the cleaning agent Z supplied from the cleaning agent supply unit 5 to the measurement unit 2, and A liquid discharge line 7 for discharging the measurement target liquid Y and the cleaning agent Z from the measurement unit 2 is also provided. Although not shown, the concentration measurement apparatus 1 may be provided with an adjustment liquid supply unit that supplies an adjustment liquid that does not absorb visible light to the measurement unit 2.

(Measurement unit 2)
The measuring unit 2 automatically measures the concentration of the heavy metal scavenger H in the measurement target liquid Y placed in the cell G. The measuring unit 2 is mainly composed of a main body unit 20 in which the measurement target liquid Y is put, and a light emitting / receiving unit 21 that emits light toward the main body unit 20 and receives the emitted light.

  Hereinafter, an example in which the light emitting / receiving unit 21 is provided only on one surface of the main body 20 will be described, but the light emitting / receiving unit 21 is provided with a light emitting unit 211 on one surface of the main body 20. A configuration in which the light receiving unit 212 is provided on a surface facing the surface may be employed.

  Here, the configuration and function of the measurement unit 2 will be described in detail with reference to FIGS. 3, 4, and 5. The detailed configurations of the measurement target liquid supply unit 4, the cleaning agent supply unit 5, the liquid supply line 6, and the liquid discharge line 7 shown in FIG. 2 will be described later.

  FIG. 3 is an exploded perspective view in which the main body 20 and the light emitting / receiving unit 21 of the measuring unit 2 are disassembled. FIG. 4 is a diagram for explaining the state of light emission and light reception performed in the measurement unit 2. FIG. 5 is an electrical wiring diagram in the light emitting / receiving unit 21.

  As shown in FIGS. 3 and 4, the main body 20 of the measurement unit 2 is not particularly limited, but is formed in a rectangular parallelepiped shape, for example. A cell G into which a measurement target liquid Y for measuring light transmittance (absorbance) is placed is provided inside the main body 20.

  The lower surface of the main body 20 is connected to the liquid supply line 6, and the upper surface is connected to the liquid discharge line 7. The main body 20 can store the liquid supplied from the liquid supply line 6 in the cell G. In addition, the liquid stored in the cell G is discharged to the liquid discharge line 7.

  A light transmitting portion 203 is formed on a surface 202 of the main body 20 that contacts the light emitting / receiving portion 21. Although the shape of the light transmission part 203 is not specifically limited, For example, it can be set as a rectangular shape. Further, the material of the light transmitting portion 203 is not particularly limited as long as it is transparent, but for example, it can be made of acrylic.

  In the main body 20, a reflection plate 201 capable of reflecting light is formed on a surface facing the surface 202 on which the light transmission portion 203 is provided. The reflection plate 201 reflects light from the light emitter 211 of the light emitting / receiving unit 21 described later, and allows the light receiver 212 to receive the reflected light.

  In order to easily reflect light on the inner surface of the main body 20, the reflection plate 201 is formed of a white plate material. On the other hand, in order to prevent light scattering, the five surfaces other than the surface on which the reflection plate 201 is provided are preferably formed of a black plate material.

  The horizontal width T shown in FIG. 4 can be adjusted according to the shape and performance of the light emitter 211 and the light receiver 212 and the concentration of the heavy metal scavenger H. The size of the main body 20 is not particularly limited. For example, the thickness t1 of the reflector is set to about 2 mm, the thickness t2 of the surface on which the light transmission unit 203 is provided is set to about 2 mm, and the left and right width T is set to about 6 mm. be able to. In this case, the capacity of the cell G can be about 0.7 mL. Further, for the light transmission part 203, the height H shown in FIG. 3 can be about 18 mm and the width W can be about 8 mm.

  In the light receiving / emitting unit 21, a light emitting body 211, a light receiving body 212, a wiring board and the like (not shown) are housed in a casing 210 provided with an opening 214 shown in FIG. 3. A power supply and output cable 213 is provided so as to protrude from the casing 210.

  A light source that emits light including white light (white light) is used for the light emitter 211. As the light source, for example, a light emitting diode (LED) is used.

  The light receiver 212 measures the intensity of light emitted from the light emitter 211. Specifically, first, as shown in FIG. 4, light emitted from the light emitter 211 is absorbed and attenuated by the measurement target liquid Y in the cell G and reflected by the reflector 201. Thereafter, the light is again absorbed and attenuated by the measurement target liquid Y in the cell G, and the intensity of the light is measured by the photoreceptor 212.

  As shown in FIGS. 3 and 4, the light receiver 212 is arranged on the same side as the light emitter 211 with respect to the cell G. At this time, it is preferable that the optical axis K1 of the light emitter 211 and the optical axis K2 of the light receiver 212 intersect on the surface of the reflector 201 (intersection P in FIG. 4). Although not particularly limited, for example, as shown in FIG. 4, the angle α of the optical axis K1 with respect to the optical axis K2 is adjusted to be 45 degrees, and the optical axis K2 of the photoreceptor 212 is orthogonal to the reflector 201. To be adjusted.

  With this configuration, most of the light emitted from the light emitter 211 and reflected by the reflector 201 does not reach the light receiver 212. That is, the light receiving body 212 receives a part of the ambient light of the light emitted from the light emitting body 211 and the light irregularly reflected by the reflecting plate 201. In this way, since the light receiving body 212 receives only a part of the light, the light emission amount is too large, and even if the light receiving amount itself cannot be measured by the light receiving body 212, the cell length is increased. There is no need to adjust the amount of light emitted.

  Further, as shown in FIG. 5, the photoreceptor 212 is obtained by dividing three photodiodes and a wavelength body of light in the visible light region into three parts (590 nm to 720 nm, 480 nm to 600 nm, 400 nm to 540 nm). A red (R) filter, a green (G) filter, and a blue (B) light that selectively passes light of red, green, and blue region components (hereinafter, referred to as red band light, green band light, and blue band light, respectively). And a filter. The R filter most easily transmits red light, the G filter most easily transmits green light, and the B filter most easily transmits blue light.

  The photoreceptor 212 uses an RGB color sensor having a photodiode D1 having an R filter, a photodiode D2 having a G filter, and a photodiode D3 having a B filter.

  The light intensity of each of the red band light, the green band light, and the blue band light that has passed through each filter among the light that has passed through the measurement target liquid Y can be simultaneously measured by the photoreceptor 212. .

  In FIG. 5, symbol L indicates a light emitting diode (LED) serving as the light emitter 211, symbols C1, C2, and C3 indicate main circuits for the photodiodes D1, D2, and D3, and symbols O1, O2 , O3 indicate operational amplifiers (operational amplifiers) for the photodiodes D1, D2, and D3. The signal of the transmitted light intensity of each band light output from the photoreceptor 212 is transmitted to the arithmetic processing unit 22 through the operational amplifiers O1, O2, and O3.

  The arithmetic processing unit 22 performs a specific arithmetic process, and the relationship between the light transmittance (absorbance) in the red, green, and blue band light and the heavy metal collector H for each type of the heavy metal collector H. A storage unit that stores data relating to the calibration graph to be displayed, and a display unit that displays the concentration and the like of the heavy metal scavenger H;

  The calculation unit can calculate the time average intensity for each band light based on the intensity signals of the red, green, and blue band lights output from the photoreceptor 212. In addition, the calculation unit subtracts the transmitted light intensity of the light that has not been absorbed from the transmitted light intensity of the light that has absorbed the specific color to obtain the light transmittance (absorbance) obtained by performing baseline correction in red, green, and blue band light. Can also be calculated.

  Moreover, the calculating part can also calculate the density | concentration of a heavy metal scavenger from the light transmittance (absorbance) in red, green, and blue band light. Specifically, since a calibration graph indicating the relationship between the light transmittance and the heavy metal scavenger is stored in the storage unit, the calculation unit calculates the heavy metal scavenger from the light transmittance based on the data of the graph. The concentration can be calculated. The greater the slope of this graph, the more accurately the concentration of heavy metal scavenger is determined.

  Thus, the measurement unit 2 can measure the concentration of the heavy metal scavenger H in the treated water S1 by measuring the light transmittance of the measurement target liquid Y, and adjust the addition amount based on the concentration. The device 13 can adjust the amount of the heavy metal scavenger H added to the waste water.

  In addition, about the measurement part 2, as mentioned above, although the structure which measures the density | concentration of the heavy metal scavenger H as an example was mentioned as an example, the density | concentration measuring apparatus 1 is not limited to this example. For example, the measurement unit 2 may measure the concentration of the heavy metal scavenger H in the measurement target liquid Y based on the oxidation-reduction potential of the treated water S1.

(Control unit 3)
The control unit 3 controls the timing at which the cleaning agent Z capable of removing the dirt derived from the liquid to be measured attached in the cell G is passed through the cell G as a control device in the concentration measuring device 1 (FIG. 2 re-reference). Specifically, in the cleaning method of the concentration measuring apparatus 1 to be described later, the control unit 3 allows the cleaning agent Z to flow into the cell G based on the light transmittance of the measurement target liquid Y measured by the measuring unit 2. It is possible to control the timing.

  The control unit 3 can cause the cleaning agent Z to flow through the cell G when the light transmittance becomes a predetermined value or less. The predetermined value is not particularly limited. For example, when measurement using Wellclin (registered trademark) is performed, the predetermined transmittance can be set to 80% in consideration of a decrease in resolution. Moreover, the control part 3 can also make the washing | cleaning agent Z flow in the cell G, when the frequency | count of measurement of the density | concentration of the heavy metal scavenger H by the measurement part 2 reaches predetermined number. The predetermined number of times is not particularly limited. Similarly, in the case where measurement using Wellclin (registered trademark) is performed, considering that the transmittance is reduced to 80% of the initial transmittance, for example, 24 times. be able to.

  The control unit 3 can be configured by a general-purpose computer including a CPU, a memory, a hard disk, and the like. The hard disk stores an OS, a program for executing each process related to the cleaning method described below, and the like.

(Measuring solution supply unit 4)
The measurement target liquid supply unit 4 illustrated in FIG. 2 supplies the measurement target liquid Y including the heavy metal scavenger H to the measurement unit 2. The measurement target liquid supply unit 4 includes a tank 40 that stores the coloring reagent X, a tank 41 that stores the measurement target liquid Y, and a pump P ₁ that allows the measurement target liquid Y stored in the tank 41 to flow into the cell G. The flow path 42 through which the measurement target liquid Y flows, the valve 43 on which the valve on the flow path 42 is opened and closed by the control unit 3, and the strainer 44 that filters unnecessary substances in the measurement target liquid Y are mainly configured. The

  Examples of the heavy metal collecting agent H contained in the measurement target liquid Y placed in the tank 41 include a dithiocarbamic acid-based heavy metal collecting agent.

  This dithiocarbamate heavy metal scavenger is not particularly limited, but dithiocarbamate, dialkyldithiocarbamate, cycloalkyldithiocarbamate, piperazine bisdithiocarbamate, tetraethylenepentamine dithiocarbamate, polyamine dithiocarbamate Etc. In addition, these 1 type may be used independently and may use 2 or more types together.

Further, in order to make it possible to measure the concentration of the heavy metal scavenger H in the measurement target liquid Y based on the light transmittance of the measurement target liquid Y, the measurement target liquid Y includes a coloring reagent X. Examples of the coloring reagent X include those containing water-soluble salts such as sulfates and hydrochlorides such as Fe ²⁺ , Fe ³⁺ , Cu ²⁺ , Zn ²⁺ , Pb ²⁺ , Ni ²⁺ , Cd ²⁺ , and Mn ^2+. Further, it is preferable to use a Fe ²⁺ or Fe ³⁺ salt because no special treatment is required at the time of color development or discharge after the end of the analysis work. When a dithiocarbamic acid heavy metal collector is used as the heavy metal collector H, it easily reacts with the dithiocarbamic acid heavy metal collector and easily develops color, so it has divalent iron ions such as ferrous chloride. It is preferable. Moreover, it is preferable that pH of the measuring object liquid Y is 6.0-7.0.

In general, when the coloring reagent X is added to a dilute aqueous solution of the heavy metal scavenger H, the color development becomes deeper as the amount of the coloring reagent X increases, but the total amount of the scavenger in water and the added heavy metal compound When the reaction amount exceeds the reaction amount, the color development does not become deeper even if the heavy metal compound addition amount is increased. Therefore, when the residual scavenger concentration in the treated water S ₁ is quantified, the coloring reagent is added to the above reaction amount (for example, about 1 to 10 times, particularly about 1.5 to 5 times the reaction amount). It is preferable.

(Cleaning agent supply unit 5)
The cleaning agent supply unit 5 shown in FIG. 2 supplies the measuring unit 2 with a cleaning agent Z that can remove dirt derived from the measurement target liquid Y such as the heavy metal scavenger H and the coloring reagent X. The cleaning agent supply unit 5 includes a tank 50 that stores the cleaning agent Z, a pump P ₂ that allows the cleaning agent Z stored in the tank 50 to flow into the cell G, a flow path 52 through which the cleaning agent Z flows, The control unit 3 mainly includes a valve 53 that opens and closes the valve on the flow path 52.

  Examples of the cleaning agent Z stored in the tank 50 include a solution containing oxalic acid, hydrochloric acid, sulfuric acid hydrogen peroxide, organic acids such as fluoric acid, nitric acid, and citric acid, chelating agents, and the like. Among these, the cleaning agent Z is preferably a solution containing oxalic acid in order to more efficiently remove dirt from the measurement target liquid Y adhering to the cell. When the cleaning agent Z contains oxalic acid, the concentration of oxalic acid is preferably 3.0 to 10.0% by mass in the total amount of the cleaning agent. Moreover, although pH of a cleaning agent is not specifically limited, In order to improve a cleaning effect more, it is preferable that it is 2.0 or less.

(Liquid supply line 6 and liquid discharge line 7)
The liquid supply line 6 illustrated in FIG. 2 allows the measurement target liquid Y or the cleaning agent Z to flow through the cell G of the measurement unit 2. Moreover, the liquid discharge line 7 is the measurement object liquid Y from which the density | concentration of the heavy metal scavenger H was measured in the measurement part 2, the cleaning agent Z from which the dirt derived from the measurement object liquid Y was removed, and other adjustment liquids from the cell G. Discharge outside. The processing method for the discharged measurement target liquid Y or cleaning agent Z is not particularly limited in the concentration measuring apparatus 1 of the present embodiment.

<Cleaning method in the concentration measuring apparatus 1>
Next, a cleaning method for the inside of the cell G performed by the concentration measuring apparatus 1 of the present embodiment will be described. Cleaning in the concentration measuring apparatus 1 is performed after the concentration of the heavy metal scavenger H in the measurement target liquid Y placed in the cell G is measured one or more times. Therefore, first, before describing the cleaning method, a method for measuring the concentration of the heavy metal scavenger H in the measurement target liquid Y will be described.

(Concentration measurement method)
First, the treated water S ₁ having the heavy metal scavenger H is dissolved in a solvent such as water, and the coloring reagent X is added to prepare the measurement target liquid Y.

  Next, a transparent adjustment liquid that does not absorb visible light (for example, pure water or a transparent sample before color development) is supplied from the liquid supply line 6 using a tube pump (for example, SMP21 manufactured by Tokyo Rika Kikai Co., Ltd.). The gas flows through the cell G of the measurement unit 2. The flow rate and the flow time are not particularly limited, but for example, the flow rate is 10 mL / min for about 3 minutes. Light from the light emitter 211 is irradiated into the adjustment liquid through the transparent portion 203 of the measurement unit 2 for about 1 minute.

  3 and 4, the light emitted from the light emitter 211 passes through the adjustment liquid and is reflected by the reflection plate 201. Thereafter, the light passes through the adjustment liquid again and is received by the photoreceptor 212 as transmitted light.

  At this time, the light receiver 212 receives the transmitted light through the three color filters of RGB. The light receiver 212 can simultaneously measure the intensities of red, green, and blue band light obtained by dividing the wavelength body of light in the visible light region into three.

  Then, the arithmetic processing unit 22 calculates the light intensity of the red, green, and blue band light by averaging the light intensities received by the photoreceptor 212 for about 1 minute. Thereby, the light transmittance of the adjustment liquid can be measured. The arithmetic processing unit 22 can set the light transmittance of the adjustment liquid to 100%.

  Next, with respect to the measurement target liquid Y that has been allowed to stand for a certain period of time after adding the coloring reagent X and developed color, the light transmittance is measured by the same method as the adjustment liquid described above.

  The higher the concentration of the heavy metal scavenger H, the lower the light transmittance (the higher the absorbance). Here, for the heavy metal scavenger H, the arithmetic processing unit 22 stores in advance the relationship between the light transmittance (absorbance) and the concentration for red, green, and blue band light as calibration graph data. Therefore, the arithmetic processing unit 22 can calculate the concentration of the heavy metal scavenger H in the measurement target liquid whose light transmittance has been measured based on the data. The arithmetic processing unit 22 can also display the density.

  In addition, when the measuring liquid Y is colored yellow by adding a coloring reagent X such as ferrous chloride, the measuring liquid Y hardly absorbs red band light and green band light. Only the blue band light which is complementary color light is absorbed. Therefore, only the blue band light needs to be considered for the light intensity.

  In addition, when the measurement target liquid Y is colored in blue, for example, the measurement target liquid Y hardly absorbs blue band light and absorbs red band light and green band light. Therefore, only the red band light and the green band light need be considered for the light intensity.

(Cleaning method)
Next, a method for cleaning the cell G in the concentration measuring apparatus 1 will be described. FIG. 6 is a flowchart showing an example of a cleaning method performed in the concentration measuring apparatus 1 of the present embodiment.

  First, a cleaning agent Z containing oxalic acid or hydrochloric acid is prepared and stored in the tank 50 (see FIG. 2 again). Subsequently, the measurement unit 2 measures the concentration of the heavy metal scavenger H in the measurement target liquid Y put in the cell G from the tank 41 a plurality of times. The measurement of the concentration is obtained by measuring the light transmittance of the measurement target liquid Y as described above (step S11).

  At this time, the control unit 3 determines whether or not the light transmittance is equal to or less than X% (X is an arbitrary value set in advance that is greater than or equal to 0 and less than 100) (step S12). When the light transmittance is not less than X%, the control unit 3 causes the measurement unit 2 to continuously measure the concentration of the heavy metal scavenger H. In the concentration measuring apparatus 1 of this embodiment, the concentration of the heavy metal scavenger H can be measured with high accuracy by evaluating the degree of contamination of the cell G while repeating these operations.

  On the other hand, when the light transmittance becomes X% or less, the control unit 3 closes the valve 42 and opens the valve 52. As a result, the cleaning agent Z stored in the tank 50 is passed through the cell G of the measuring unit 2. In this way, the cell G is washed by removing the dirt derived from the heavy metal scavenger H and the coloring reagent X (step S13).

  About the washing | cleaning method, the cleaning agent Z is put so that it may fill in the cell G, for example, is immersed and washed for about 18 minutes. Thereby, the dirt adhering to the cell is gradually decomposed and the dirt is reduced. Then, the test water is passed through the cell G in order to discharge the cleaning waste liquid from the cell. Although the time for allowing the test water to flow through the cell G is not particularly limited, it is, for example, about 2 minutes. Thereby, a cleaning agent can be discharged | emitted from the cell G and the density | concentration measurement of the heavy metal scavenger H can be performed again.

  As this stain, for example, when a dithiocarbamic acid heavy metal collector is used as the heavy metal collector H and ferrous chloride is used as the coloring reagent X, a dithiocarbamide group and iron chelate can be used. Examples include dirt with a slow decomposition rate. It is preferable that the cleaning agent Z for the soil contains oxalic acid or hydrochloric acid. This cleaning agent Z reacts with at least one of a dithiocarbamide group and iron, which are components of dirt. And the cleaning agent Z decomposes | disassembles a dithiocarbamide group, or when a chelating agent is contained, a chelating agent substitutes a metal, substitutes iron, and a chelate of a dithiocarbamide group and iron is carried out. It can be disassembled and removed from the cell G. Thereby, the cell G can be cleaned.

  As described above, in the concentration measuring apparatus 1 of the present embodiment, when the light transmittance in the measurement target liquid Y becomes X% or less, the control unit 3 causes the cleaning agent Z to flow through the cell G, and the cell Can be washed.

  Further, as another example, the control unit 3 can cause the cleaning agent to flow through the cell G when the number of times of measurement of the concentration of the heavy metal scavenger H by the measurement unit 2 reaches a predetermined number. FIG. 7 is a flowchart showing another example of the cleaning method performed in the concentration measuring apparatus 1 of the present embodiment.

  In the example shown in FIG. 7, the measurement unit 2 measures the light transmittance of the measurement target liquid Y (step S <b> 11), and then the control unit 3 performs the measurement of the light transmittance N times (N is 1 or more). It is determined whether or not a predetermined value has been reached (step S22). When the number of times of measurement of the light transmittance has not reached N times, the control unit 3 causes the measurement unit 2 to continuously measure the concentration of the heavy metal scavenger H.

  On the other hand, when the number of times the light transmittance is measured reaches N times, the control unit 3 closes the valve 42 and opens the valve 52 as in the example shown in FIG. As a result, the cleaning agent stored in the tank 50 is passed through the cell G of the measuring unit 2. In this manner, the cell G is washed by removing the dirt derived from the heavy metal scavenger H and the color reagent X (step S13).

As described above, in the concentration measuring apparatus 1, the control unit 3 causes the cleaning agent Z to flow through the cell G at a specific timing, thereby cleaning the cell G. Therefore, the concentration measurement error of the heavy metal scavenger H due to dirt adhering to the cell can be efficiently reduced, and the concentration measurement can be continuously performed while maintaining the concentration measurement accuracy. Then, the coagulating sedimentation processing system 10 having a concentration measuring apparatus 1, it is possible to reduce the error of the amount of heavy metal scavenger H into the waste water S _0.

(Modified embodiment)
Next, the configuration of a modified embodiment of the concentration measuring apparatus 1 of the present embodiment will be described. FIG. 8 is a diagram illustrating the configuration of the concentration measuring apparatus 1 according to a modification of the present embodiment. The concentration measuring apparatus 1 of the present modification is different from the concentration measuring apparatus 1 described with reference to FIG. 2 in that it includes a coloring reagent supply unit 8, but the other configurations and functions are substantially the same. It is. Therefore, only the configuration and function of the color reagent supply unit 8 will be described here.

The coloring reagent supply unit 8 includes a tank 80 that stores the coloring reagent X, a pump P ₃ that discharges the coloring reagent from the tank 80 toward the cell G, and a flow that allows the coloring reagent to flow from the tank 80 toward the cell G. The road 82 is mainly constituted.

By the pump P _3, coloring reagent through the flow path 82 is placed in the cell G. As a result, the coloring reagent reacts in the cell G with the heavy metal scavenger H put in the cell from the liquid supply line 6. Thus, in the concentration measuring apparatus 1 of the present modification, even if the heavy metal scavenger H in the treated water S ₁ does not react with the color reagent X before entering the cell G, the color reagent in the cell G It reacts with X, and it becomes possible to measure the light transmittance of the heavy metal scavenger H in the measurement unit 2.

  Hereinafter, the effects of the present invention will be specifically described with reference to Examples and Comparative Examples of the present invention.

<Experimental conditions>
Sample prepared by dissolving a dithiocarbamic acid heavy metal scavenger (Wellculin (registered trademark) (manufactured by Kurita Kogyo Co., Ltd.)) in pure water so that the concentration of the dithiocarbamic acid heavy metal scavenger is 100 mg / L. Prepared. A coloring reagent (ferrous chloride solution) was added to this sample, and the sample was colored to prepare a measurement target solution. The pH was adjusted to 6.5.

  As the cleaning agent, an aqueous solution prepared by adjusting the concentration of oxalic acid and hydrochloric acid to 9.8% by mass in the total amount (Examples 1 and 2) was used. Moreover, the aqueous solution which prepared the density | concentration of the oxalic acid to 4.0 mass% and 3.0 mass% in the whole quantity was also used (Examples 3 and 4). Furthermore, sulfuric acid aqueous hydrogen peroxide solution prepared by adjusting sulfuric acid to 9.8% by mass and hydrogen peroxide to 5.8% by mass in the total amount was also used (Example 5). Moreover, the aqueous solution which adjusted the density | concentration of a sulfuric acid, phosphoric acid, a citric acid, and EDTA to 9.8 mass% in the whole quantity was also used (Examples 6-9).

  First, the light transmittance of the transparent sample before adding the reagent to the cell G was measured using the concentration measuring apparatus 1. The light transmittance was adjusted to 100%.

  Next, the light transmittance of the measurement target liquid was measured using the concentration measuring apparatus 1. The light transmittance was measured 24 times. Specifically, the intensity change of the blue band (400 nm to 540 nm) having a transmittance of 100% was measured 24 times in the light transmittance measurement. After measuring the concentration of the dithiocarbamic acid heavy metal scavenger 24 times, the cell G was washed by immersing it in the cell G for 18 minutes. Thereafter, the measurement of the concentration of the dithiocarbamic acid heavy metal scavenger 24 times and the cleaning with the cleaning agent for 18 minutes were repeated.

<Experimental result>
The measurement results are shown in FIG. FIG. 9 is a graph showing changes in the light transmittance of the liquid to be measured when various cleaning agents are used. FIG. 9 shows that the lower the light transmittance is, the more dirt is deposited in the cell. Table 1 is a table showing cleaning rates of various cleaning agents. Here, the cleaning rate is expressed by the following equation.

  As shown in FIG. 9 and Table 1, it was found that the cleaning agent containing 9.8% by mass of oxalic acid and the cleaning agent containing sulfuric acid hydrogen peroxide had a very excellent cleaning effect on dirt. . Moreover, it turned out that 9.8 mass% hydrochloric acid and 4.0 mass% oxalic acid have equivalent detergency. In addition, it was found that the cleaning agent containing 4.0% by mass of oxalic acid stably maintains the light transmittance of about 70%, although the cleaning effect is inferior to that of 9.8% by mass of oxalic acid. . On the other hand, it was found that a cleaning agent containing sulfuric acid, phosphoric acid, citric acid or EDTA has a smaller cleaning effect than oxalic acid and hydrochloric acid.

  Oxalic acid, hydrochloric acid, and sulfuric acid-hydrogen peroxide are acids that have a high oxidizing power, and are therefore considered to have an excellent cleaning effect on cell stains.

DESCRIPTION OF SYMBOLS 1 Concentration measuring apparatus 2 Measuring part 20 Main body part 21 Light emitting / receiving part 3 Control part 4 Measuring object liquid supply part 40 Tank 41 Channel 42 Valve 5 Cleaning agent supply part 50 Tank 51 Channel 52 Valve 6 Liquid supply line 7 Liquid discharge line 8 Coloring reagent supply unit 10 Coagulation sedimentation processing system 11 Water channel 12 Tank 13 Addition amount adjusting device G Cell H Heavy metal collecting agent X Colored sample Y Measurement target solution Z Cleaning agent

Claims (10)

A measurement unit that automatically measures the concentration of the heavy metal scavenger in the liquid to be measured placed in the cell;
A concentration measurement apparatus comprising: a control unit that controls a timing at which a cleaning agent capable of removing dirt derived from the measurement target liquid attached in the cell is passed through the cell.   The concentration measurement apparatus according to claim 1, wherein the measurement unit measures the concentration of the heavy metal scavenger based on the light transmittance of the measurement target liquid. When the light transmittance is below a predetermined value,
The concentration measuring apparatus according to claim 2, wherein the controller causes the cleaning agent to flow through the cell. When the number of measurements of the concentration of the heavy metal scavenger by the measurement unit reaches a predetermined number of times,
The concentration measuring apparatus according to claim 1, wherein the control unit causes the cleaning agent to flow through the cell.   The concentration measuring apparatus according to claim 1, wherein the heavy metal scavenger is a dithiocarbamic acid-based heavy metal scavenger.   The concentration measuring apparatus according to claim 1, wherein the measurement target liquid contains a coloring reagent having a divalent iron ion.   The cleaning agent contains at least one selected from oxalic acid, hydrochloric acid, sulfuric acid hydrogen peroxide, hydrofluoric acid, nitric acid, sulfuric acid, citric acid, and a chelating agent. The concentration measuring apparatus according to item 1.   The concentration measuring apparatus according to claim 7, wherein the cleaning agent contains oxalic acid or hydrochloric acid.   The concentration measuring apparatus according to claim 8, wherein the oxalic acid is contained in an amount of 3 to 10 mass% in the total amount of the cleaning agent. A step of automatically measuring the concentration of the heavy metal scavenger in the liquid to be measured placed in the cell;
A step of cleaning the inside of the cell by allowing a cleaning agent capable of removing dirt derived from the measurement target liquid attached to the cell to flow through the cell at a predetermined timing. Cleaning method.