JP3422083B2 - Method and apparatus for measuring chromaticity in sewage or wastewater treatment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chromaticity measuring method and apparatus in a sewage treatment or wastewater treatment process.

[0002]

2. Description of the Related Art Generally, in order to purify raw water taken from rivers or secondary treated water of sewage, a coagulant is injected and mixed in raw water in a coagulating sedimentation tank, and suspended substances in the raw water are treated by stirring and retaining. (Sand, clay, algae, and other organic matter) are aggregated, precipitated, and separated. This process incorporates chlorine treatment for the purpose of algicidal treatment and removal of chromaticity components such as iron and manganese.

[0003] On the other hand, with the increasing prevalence of sewerage in recent years, effective utilization of sewage treated water is expected as a water resource in urban areas. Especially treated sewage water, which is said to exceed 8 billion m ³ per year, has the potential as a stable water resource in urban areas, and there are expectations for the reuse of treated water in various forms. One of them is reuse for landscape water or hydrophilic water.

As a form of reuse as scenic water, it is considered that the treated water is introduced into an existing water channel or used as water retention such as a moat, or as water for amenity facilities such as parks, fountains, murmuring, etc. . Further, hydrophilic water is reused water that is presumed to be touched by humans such as playing in water.

As described above, in order to reuse the treated sewage water as scenic water / hydrophilic water, sufficient consideration is given to hygienic safety of the reused water, sensory comfort, reuse technology, and complementary measures. Need to do.

In order to reuse the treated sewage water, the basic water quality items to be noted are, in addition to the treated water quality required for the treated sewage water up to now, the removal of the number of coliform bacteria, odor and chromaticity. It becomes a problem. Especially, for the removal of the above-mentioned Escherichia coli and odor and chromaticity, high-level treatment, for example, ozone treatment for organic matter,
A method of decomposing inorganic substances has been considered and is also adopted in an actual plant. That is, ozone has a strong oxidizing power and sterilizing power, and can effectively sterilize, deodorize and decolorize as compared with other methods. Particularly in the field of water purification, ozone treatment has recently been put into practical use for the purpose of measures against THM (trihalomethane) caused by chlorine treatment and measures against deterioration of water quality of raw water.

From such a background, chromaticity is one of the important indexes when monitoring and controlling an advanced processing system for the purpose of removing the above-mentioned substances, and this chromaticity is automatically and continuously measured. It is desired to realize a method for measuring in real time.

[0008] Chromaticity is an index originally used in the treatment of clean water. According to the clean water test method (1985 version), "chromaticity is a kind of yellow or yellow which is exhibited by soluble substances and colloidal substances contained in water. It is the degree of yellow-brown color, and is mainly measured for colors with the same color tone as that of the humic substances derived from the geology. " Usually, one degree corresponds to the coloration when 1 liter of purified water contains 1 mg of platinum and 0.5 mg of cobalt in the chromaticity standard solution.

In general, the platinum / cobalt method is adopted as the method for measuring chromaticity by the water test method. This method uses potassium chloroplatinate (K ₂ P
Tcl ₆₎ 2.49 g and cobalt chloride (CoCl ₂ · 6
H ₂ O) 2.02 g was taken in a 1-liter volumetric flask,
After dissolving with 200 ml of hydrochloric acid, add purified water to bring the total volume to 1
This is a method of measuring 100 ml of this chromaticity standard stock solution in 1 liter of a volumetric flask, adding purified water to bring the total volume to 1 liter and using the chromaticity standard solution as a chromaticity standard solution, and measuring the sample solution by the colorimetric method. 4. See chromaticity section).

That is, the maximum light absorption of humic acid, which is the main cause of chromaticity, is in the ultraviolet region and the absorption of visible light is extremely small, but the chromaticity itself is the degree of color appealing to human senses. Because it's there, you have to measure it with the naked eye.

Further, according to the water supply test method “5. Single color display of color” and the factory drainage test method (JIS K0102) “11. Chromaticity”, “single color display of color means dominant wavelength (hue), stimulation purity”. And the lightness, which indicates the state of the color of colored water for which the chromaticity cannot be measured. " The dominant wavelength refers to the wavelength of light that contributes most to the coloration of the sample, the hue refers to the vividness of the color exhibited by the dominant wavelength, and the lightness refers to the brightness.

The monochromatic display is measured by measuring the transmittance of the sample water at each wavelength of visible light (400 to 700 nm) using a photoelectric spectrophotometer to obtain three stimulus values. It is a method for obtaining the brightness and the dominant wavelength (hue).

Furthermore, as a method for measuring the chromaticity of landscape water / hydrophilic water, in the “Scenic Treatment Water Landscape / Hydrophilic Water Quality Examination Manual (draft)” issued by the Ministry of Construction in 1990, the above-mentioned water supply test was conducted. It is said to follow the measuring method of "4. chromaticity" in the method. However, there is a statement that sewage treatment water, such as dyeing wastewater, needs to be examined.

In addition, there is an article titled "Establishment of Standards for Water Quality in Tap Water" by the Ministry of Health and Welfare in the Water Supply Association Magazine, Vol. 62, No. 2 (February, 1993 issue), which says that the wavelength is around 390 nm. Method to calculate the chromaticity of the sample water from the calibration curve created with the chromaticity standard solution by measuring the absorbance with
(Abbreviated as transmitted light measurement method).

[0015]

However, such a chromaticity measuring method in the reuse of sewage or waste water cannot continuously measure the sample water, and the quick measures against the fluctuation of the water quality are insufficient. There is a problem that it is not always satisfactory for monitoring and controlling advanced treatment of sewage. Further, there is a problem that it is difficult to obtain the chromaticity without being influenced by the color tone.

For example, the platinum-cobalt method is a colorimetric method by visual observation with the naked eye, and this visual observation can be replaced by the amount of transmitted light, but the color tone cannot be distinguished. In clean water treatment, yellowish or yellowish brown color may be evaluated, but in the case of sewage or wastewater reuse, it is necessary to evaluate chromaticity in the entire visible light range, and simple colorimetry is not enough. It can be said that there is.

In particular, when the sewage or wastewater is used as a monitoring / control for using the sewage or drainage as scenic water / hydrophilic water by a high-level treatment system, continuous measurement as well as color tones other than yellowish or yellowish brown can be performed. It can be evaluated. Almost all treated water that has been highly treated by ozone treatment has a yellowish or yellowish brown color, but it is also necessary to measure the chromaticity before advanced treatment for monitoring and control, so it is possible to evaluate other color tones. Required. When dyeing wastewater flows in, the above-mentioned color tone evaluation is highly necessary.

Further, the quality of water such as sewage often changes depending on the treatment plant, the season, and the day of the week, and it is troublesome for the operator to change the measurement wavelength or the chromaticity conversion formula according to the change. Cause confusion.

Although the JIS method (monochromatic display method) can evaluate the color tone, it requires data at 20 nm intervals in the range of 400 to 700 nm of visible light. There is a drawback that it becomes large.

Another requirement for the chromaticity measuring device is that it has a high correlation with the measurement by the platinum-cobalt method. In other words, the “Scenic Treatment Water Landscape / Hydrophilic Water Quality Study Manual (Draft)” issued by the Ministry of Construction is based on the platinum / cobalt method, so even if general uniformity is taken into consideration, Conformity and correlation are considered preferable.

In view of the above problems, the present invention is particularly suitable for monitoring and controlling advanced treatment of sewage or the like, which enables automatic and continuous measurement, and has correlation with the measurement by the platinum-cobalt method. It is an object of the present invention to provide a method and an apparatus for measuring chromaticity in the treatment of sewage or waste water with high quality.

[0022]

In order to solve the above-mentioned problems, the invention according to claim 1 has a wavelength of sample water of 370 nm to
Absorbance at two points of 410 nm and a wavelength of 460 nm is measured, the obtained absorbance is converted into a transmitted light rate based on an arithmetic expression, and then the transmitted light rate is multiplied by a sensitivity coefficient of each wavelength to calculate a color transmittance. A method for measuring chromaticity in sewage or wastewater treatment, in which the chromaticity is obtained from a chromaticity calibration curve in which the color transmittance is plotted against the chromaticity of a standard solution, and the wavelength is 390 nm and 4
The calculation procedure of the color transmittance when 60 nm is used is as follows:
The sensitivity coefficient of the three stimulus values at 90 nm is X ₃₉₀ , Y ₃₉₀ ,
Z ₃₉₀ , the sensitivity coefficient at a wavelength of 460 nm is X ₄₆₀ ,
Y ₄₆₀ and Z ₄₆₀ , with wavelengths of 390 nm and 460 nm
Transmittances T ₃₉₀ and T ₄₆₀ obtained by converting the absorbance of ## _EQU1 ## Color transmittance (%) = (X ₃₉₀ + Y ₃₉₀ + Z ₃₉₀ ) × T ₃₉₀ +
It is characterized by being obtained by the formula (X ₄₆₀ + Y ₄₆₀ + Z ₄₆₀ ) × T ₄₆₀ .

Further, in the invention according to claim 3, a light source is arranged in one of the measuring cells into which the sample water flows, with a condenser lens interposed, and a light source is arranged in the other of the measuring cells with a condenser lens interposed. A light receiving element, a wavelength selection filter arranged between the light receiving element and the condenser lens to select a target wavelength from two or more wavelengths, and an absorbance at the selected specific wavelength of the light receiving element. Accepted as received light data, the obtained absorbance is converted into the transmitted light rate based on an arithmetic expression, and the color transmittance is calculated by multiplying by the sensitivity coefficient of each wavelength, and the color transmittance is calculated with respect to the chromaticity of the standard solution. And a calculation and control signal output unit for obtaining and outputting chromaticity from the plotted chromaticity calibration curve,
Color transmission when wavelengths of 390 nm and 460 nm are used
The following is characterized by calculating the excess by the following calculation.
Provided is a chromaticity measuring device for water or wastewater treatment . Color transmittance (%) = (X ₃₉₀ + Y ₃₉₀ + Z ₃₉₀ ) × T ₃₉₀ +
(X ₄₆₀ + Y ₄₆₀ + Z ₄₆₀ ) × T ₄₆₀ X ₃₉₀ , Y ₃₉₀ , Z ₃₉₀ : 3 stimuli at a wavelength of 390 nm
Value sensitivity coefficients X ₄₆₀ , Y ₄₆₀ , Z ₄₆₀ : Sensitivity coefficient at wavelength of 460 nm
Number T ₃₉₀ : Transmitted light obtained by converting the absorbance at a wavelength of 390 nm
Ratio T ₄₆₀ : Transmitted light obtained by converting the absorbance at a wavelength of 460 nm
Rate where, in the invention of claim 1 and 3 wherein, in the
Convert the measured absorbance (Abs) into transmitted light rate (%)
Arithmetic expressions for the transmitted light rate (%) = 10 - to the ^(Abs)
It is good.

[0024]

According to such a chromaticity measuring method and measuring apparatus, the sample water whose chromaticity is to be measured enters the measuring cell, the wavelength preset by the wavelength selection filter is selected, and then the light source is turned on. , The light emitted from the light source enters the measuring cell through the condenser lens, passes through the sample water, and is received by the light receiving element through the condenser lens and the wavelength selection filter, and the absorbance at the selected specific wavelength is received. It is obtained as light reception data of the element. This absorbance is input to the calculation and control signal output unit, converted into the transmitted light rate based on the calculation formula, and the color transmittance is calculated by multiplying the sensitivity coefficient of each wavelength, and the color transmission is compared with the chromaticity of the standard solution. The chromaticity value is obtained from the chromaticity calibration curve in which the degree is plotted.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of a measuring apparatus to which the chromaticity measuring method according to the present invention is applied will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a structural example of an automatic chromaticity measuring apparatus to which this embodiment is applied. In the figure, 1 is a measuring cell, and condenser lenses 2 are provided on both sides of this measuring cell 1. , 3 are arranged. Reference numeral 4 is a light source arranged in the vicinity of the condenser lens 2, 5 is a light receiving element arranged in the vicinity of the condenser lens 3, 6 is a wavelength selection filter arranged between the condenser lens 3 and the light receiving element 5, Reference numeral 7 is a stepping motor, 8 is a calculation and control signal output unit, and 9 is a suspended matter removal filter. The wavelength selection filter 6 is arranged to select a target wavelength from two or more wavelengths.

More specifically, as will be described later in detail, the wavelength selection filter 6 is for measuring the absorbance at one or more wavelengths in the visible light wavelength range, In this example, the wavelength of the sample water is 370 nm to 410 nm
And measuring the absorbance at two points with a wavelength of 460 nm.

The outline of the operation at the time of measuring the chromaticity by such a measuring device is as follows. That is, sample water 1 whose chromaticity should be measured
0 is first filtered by the suspended matter removal filter 9 and then
It enters into the cell from the bottom wall side of the measuring cell 1 via the conduit 11. At this time, excess sample water 10 is overflow pipe 12
Overflow through.

Then, the wavelength selection filter 6 is rotated by driving the stepping motor 7, and the wavelength selection filter 6 selects a preset wavelength before turning on the light source 4. The driving of the stepping motor 7 and the lighting of the light source 4 are performed based on the output signal of the calculation and control signal output unit 8.

Then, the light emitted from the light source 4 is condensed by the condenser lens 2.
From inside to the measurement cell 1 and through the sample water 10 and then through the condenser lens 3 and the wavelength selection filter 6 to the light receiving element 5
The light absorbency at the selected specific wavelength is input to the calculation and control signal output unit 8 as the light reception data of the light receiving element 5, and the chromaticity value is calculated based on the measurement principle described below.

The analysis results of various data which are the basis of the chromaticity measurement in this embodiment will be described below.

In FIG. 2, the sewage secondary treated water is subjected to ozone treatment under constant conditions, and a sample is taken at each ozone treatment time (every 20 minutes in the illustrated example) to obtain a platinum cobalt method (colorimetric method). It is a graph which compared the result of having measured chromaticity using the transmitted light measuring method. According to FIG. 2, it is considered that the measurement results of the above two measurement methods do not match, and the process of decolorization by ozone is different.

The difference in the above measurement results will be explained based on the comparison of the absorbance spectra of the platinum cobalt standard solution and the sample water. FIG. 3 is a graph showing an absorbance spectrum in a 50 mm cell having a wavelength of 350 nm to 800 nm for the same sample water and platinum cobalt standard solution as in FIG. 2, and comparing both graphs, the measured wavelength in the transmitted light measurement method is 39.
The absorbance at 0 nm is almost the same, but the platinum-cobalt standard solution once shows a weak peak at a wavelength of 460 nm and then becomes zero on the long wavelength side from 550 nm. The absorbance has reached the bottom.

A difference in color tone corresponding to the difference in the above-mentioned absorbance spectra was also observed by the colorimetric method (the sample water became a dull yellowish brown color), and it was difficult to determine the chromaticity by the platinum-cobalt method. found.

Therefore, let us consider how the absorbance spectrum shown in FIG. 3 appears in human vision. FIG. 4 is a graph plotting the sensitivity of the visual cells to the wavelength of light, that is, the correlation between the sensitivity coefficient (%) of the three stimulus values received by human visual cells and the wavelength (nm). 10
It is set to 0% and is expressed as a relative ratio.

The three stimulus values mean that the stimulus that the eye receives from the color mainly has a strong red sensation, a strong green sensation and a bluish purple sensation. The sensation depends on the mixing ratio of these three stimuli. Therefore, the wavelength groups of light that give each stimulus to the eye are grouped into X, Y, and Z series, and the transmittance of the sample water for each wavelength of light is tabulated for each series. It is obtained by multiplying the obtained value by a coefficient.

To further describe this, the human retina has cones, which are photoreceptor cells involved in vision, and respond to three colors. This is usually called tristimulus, and the X that responds to red is 580
It has the maximum sensitivity to light having a wavelength near nm, Y reacting with green has a maximum sensitivity of 540 nm, and Z reacting with blue has a maximum sensitivity to light having a wavelength near 440 nm. A person can perceive and distinguish the colors by combining the above three colors. And it has been clarified that the amount of light received by visual cells varies with wavelength even if it receives light of the same intensity (see Gihodo Publishing, edited by Color Story Editor, Color Story 1). .

In view of the above, in the present embodiment, the following method was implemented with the main object of obtaining a chromaticity conversion method in consideration of human visual sensitivity. First, the absorbance of sample water is measured at the measurement wavelengths of 390 nm and 460 nm, which show the characteristic tendency of the platinum-cobalt standard solution, using the measuring device of FIG. What is actually reflected in human vision is the wavelength of the light transmitted through the sample. Next, the absorbance (Ab
s) is converted into transmitted light rate (%).

Transmitted light rate (%) = 10 ^{− (Abs))} (1) Next, the obtained transmitted light rate of each wavelength is obtained from FIG. The color transmittance is calculated by multiplying by the sensitivity coefficient. This calculation procedure will be described below. That is, from FIG. 4, sensitivity coefficients X ₃₉₀ = 0 (%), Y ₃₉₀ = 0 (%), and Z ₃₉₀ = at ₃₉₀ nm.
1.5 (%), sensitivity coefficient X at 460 nm
₄₆₀ = 16 (%), Y ₄₆₀ = 6.5 (%), Z ₄₆₀ = 88
(%). Using this value, the color transmittance is calculated by the following equation.

Color transmittance (%) = (X ₃₉₀ + Y ₃₉₀ + Z ₃₉₀ ) × T ₃₉₀ +
(X ₄₆₀ + Y ₄₆₀ + Z ₄₆₀ ) × T ₄₆₀ (2) Here, X, Y, and Z are sensitivity coefficients, T is the transmitted light ratio, and the subscript indicates the wavelength.

Table 1 shows that each chromaticity of the platinum-cobalt chromaticity standard solution is 0.
The results of measuring the absorbance (E390, E460), the transmitted light rate (T390, T460), and the color transmittance (%) are shown for -100 degrees.

[0042]

[Table 1]

FIG. 5 is a calibration curve graph in which the color transmittance is plotted against the chromaticity of the standard solution shown in Table 1. As shown in the figure, the chromaticity (degree) and the color transmittance (%) show a good correlation, and the chromaticity can be obtained from the color transmittance based on this straight line. The linear equation and correlation coefficient are as follows.

Color transmittance (%) = − 0.3062 × (chromaticity) +111.
9837 (3) Correlation coefficient = 0.99896 The chromaticity of the actual sample water was determined using the above method. Figure 6
Is the same as in Fig. 2 and Fig.
The absorbance at 0 nm and 460 nm was measured, and the above formula (1) was used.
After calculating the color transmittance from (2), the change in chromaticity converted by the equation (3) with respect to the ozone treatment time (minutes) is shown. At the same time, the platinum cobalt method and the transmitted light measurement method are used for comparison. The change in chromaticity obtained is also shown.

According to FIG. 6, it can be seen that the chromaticity obtained from the color transmittance substantially agrees with the chromaticity obtained by the platinum-cobalt method. In particular, when the chromaticity is obtained from the color transmittance, there is an advantage that it is possible to evaluate even sample water for which it is difficult to determine the chromaticity by the colorimetric method when the ozone treatment is not progressing.

From the above results, in this embodiment, the measurement wavelength was 3
The absorbance (transmitted light rate) at two points of 90 nm and 460 nm is measured, and the color transmittance is calculated from the sensitivity coefficient for the wavelength of the light visually perceived by humans, and the color is calibrated by calibrating with a platinum-cobalt chromaticity standard solution. Established a way to do. The cell used for measuring the absorbance was a 50 mm cell, but an appropriate cell length is selected and used according to the color density of the sample water. In other words, if the color is light, use a cell of 50 mm or more, and if the color is dark, 50 m or more.
Using a cell of m or less, a calibration curve is newly prepared using a platinum-cobalt standard solution, and the chromaticity is obtained.

Further, the measurement wavelength of 390 nm is a wavelength based on the method for measuring transmitted light of tap water, but it is usually 370 nm to 410.
It is said that a wavelength in the vicinity of nm is suitable for chromaticity conversion, and therefore the measurement is not limited to 390 nm, and any wavelength within the above range may be adopted.

[0048]

As described in detail above, according to the present invention, the sample water whose chromaticity is to be measured transmits the light based on the wavelength selected by the wavelength selection filter in the measuring cell and the selected specific water. The chromaticity value can be continuously measured by the calculation and calibration curve means from the absorbance based on the received light data of the light receiving element at the wavelength. In particular, in this embodiment, a chromaticity conversion method considering human visual sensitivity is adopted, and the absorbance of the sample water, which is the wavelength of the light transmitted through the sample visually, is converted into the transmitted light rate, and the transmitted light rate Is calculated by multiplying the sensitivity coefficient of each wavelength to the color transmittance, and the chromaticity is obtained from the chromaticity calibration curve in which the color transmittance is plotted against the chromaticity of the standard solution. It is possible to evaluate near chromaticity.

Further, it is not sufficient to evaluate only yellowish or yellowish brown color such as reuse of sewage or waste water, and the demand for evaluating chromaticity and distinguishing color tone in the entire visible light range is satisfied. Since the chromaticity is converted from only the absorbance regardless of the change in water quality, the effect of high versatility can be obtained.

Unlike the conventional naked-eye colorimetric method, objective measurement is possible, and visible light of 400 to 400
It is possible to continuously measure the absorbance measurement data in the range of 700 nm without the need to upsize the device, and it is possible to evaluate the color tone other than yellowish or yellowish brown. Since it satisfies the requirements for processing monitoring and control and has a high correlation with the measurement by the platinum-cobalt method, it is possible to provide a preferable chromaticity measuring method and apparatus in terms of general uniformity. it can.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration example of a chromaticity measuring device according to this embodiment.

FIG. 2 is a graph comparing the results of measuring the chromaticity of a sample for each ozone treatment time using a platinum cobalt method and a transmitted light measurement method.

[Figure 3] Wavelength 3 for sample water and platinum-cobalt standard solution
The graph which shows the light absorption spectrum of 50 nm-800 nm.

FIG. 4 is a graph plotting the correlation between the sensitivity coefficient of three stimulus values received by human visual cells and the wavelength.

FIG. 5 is a calibration curve graph in which the color transmittance is plotted against the chromaticity of the standard solution.

FIG. 6 is a graph plotting changes in chromaticity of sample water with respect to ozone treatment time based on this example.

[Explanation of symbols]

1 ... Measuring cell 2, 3 ... Condensing lens 4 ... Light source 5 ... Light receiving element 6 ... Wavelength selection filter 7 ... Stepping motor 8 ... Calculation and control signal output section 9 ... Floating matter removal filter 10 ... Sample water 12 ... Overflow pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Noguchi 2-17 Osaki, Shinagawa-ku, Tokyo Meidensha Co., Ltd. (56) Reference JP-A-4-315020 (JP, A) JP-A-3- 189542 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 21/00-21/61

Claims (4)

(57) [Claims] 1. The absorbance of sample water at two points of 370 nm to 410 nm and 460 nm is measured, and the obtained absorbance is converted into a transmitted light rate based on an arithmetic expression, and then the transmitted light rate of each wavelength is calculated. This is a method for measuring chromaticity in sewage or wastewater treatment, in which the color transmittance is calculated by multiplying the sensitivity coefficient, and the chromaticity is obtained from the chromaticity calibration curve in which the color transmittance is plotted against the chromaticity of the standard solution. The calculation procedure of the color transmittance when 390 nm and 460 nm are used is that the sensitivity coefficient of the tristimulus value at the wavelength of 390 nm is X ₃₉₀ , Y ₃₉₀ , and Z ₃₉₀ , and the wavelength is 460 nm.
The sensitivity coefficients in the _{X 460, Y 460, Z 460} , and the wavelength
The absorbance obtained by converting the absorbance at 390 nm and 460 nm
With light transmittance T ₃₉₀ and T ₄₆₀ , color transmittance (%) = (X ₃₉₀ + Y ₃₉₀ + Z ₃₉₀ ) × T ₃₉₀ +
(X ₄₆₀ + Y ₄₆₀ + Z ₄₆₀ ) × T _{460 The} method for measuring chromaticity in sewage or wastewater treatment, characterized by the formula. 2. Absorbance (Abs) measured by the above
2. The method for measuring chromaticity in sewage or wastewater treatment according to claim 1, wherein an arithmetic expression for converting the above into a transmitted light rate (%) is a transmitted light rate (%) = 10 ^{− (Abs)} . 3. A light source in which the sample water is arranged by interposing one the condenser lens of the measuring cell flowing, a light receiving element disposed interposing a condenser lens to the other of the measuring cell, the photodetection A wavelength selection filter arranged between an element and a condenser lens to select a target wavelength from two or more wavelengths.
And, the absorbance at the selected specific wavelength is accepted as the received light data of the light receiving element, the obtained absorbance is converted to the transmitted light rate based on the arithmetic expression, and the color transmittance is calculated by multiplying it by the sensitivity coefficient of each wavelength. In the case of using 390 nm and 460 nm as wavelengths , a calculation and control signal output unit that obtains and outputs chromaticity from a chromaticity calibration curve in which color transmittance is plotted against chromaticity of a standard solution is output . Color transparency
A chromaticity measuring device for sewage or wastewater treatment, which is characterized by calculating the excess by the following calculation . Color transmittance (%) = (X ₃₉₀ + Y ₃₉₀ + Z ₃₉₀ ) × T ₃₉₀ +
(X ₄₆₀ + Y ₄₆₀ + Z ₄₆₀ ) × T ₄₆₀ X ₃₉₀ , Y ₃₉₀ , Z ₃₉₀ : 3 stimuli at a wavelength of 390 nm
Value sensitivity coefficients X ₄₆₀ , Y ₄₆₀ , Z ₄₆₀ : Sensitivity coefficient at wavelength of 460 nm
Number T ₃₉₀ : Transmitted light obtained by converting the absorbance at a wavelength of 390 nm
Ratio T ₄₆₀ : Transmitted light obtained by converting the absorbance at a wavelength of 460 nm
rate 4. Absorbance (Abs) measured by the above
The chromaticity measuring device for sewage or wastewater treatment according to claim 3 , wherein is converted into a transmitted light rate (%) by the following calculation . Transmitted light rate (%) = 10- ^(Abs)