JPH07198593A - Chromaticity measuring method and apparatus in sewage or drain disposal - Google Patents

Abstract

PURPOSE:To provide a chromaticity measuring method and apparatus in the disposal of sewage or drain which enables the measuring of chromaticity automatically and continuously for the purposes of monitoring and controlling a high-level proposal of sewage or the like and moreover, is high in correlation with a measurement by a platinum/cobalt method. CONSTITUTION:In this chromaticity measuring method, absorbance is measured bear 390nm in the wavelength of a sample water to calculate the chromaticity of the sample water from a calibration curve prepared by a color standard liquid. Thereafter, the absorbance is measured at one or two or more wavelengths within a visible light wavelength area separately about the sample water and the color of the sample water is corrected based on the height of the peak of the absorbance at a specified wavelength measured. This chromaticity measuring apparatus includes a light source 4 arranged on one side of a measuring cell 1, and a photodetector 5 arranged on the other side thereof, a wavelength selection filter 6 to select a desired wavelength from two wavelengths or more and an arithmetic/control signal output section 8 which receives the absorbance at a specified wavelength selected as photodetecting data of the photodetector 5 to calculate the chromaticity value by an arithmetic means while correcting the value.

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. In particular, treated sewage water, which is said to exceed 8 billion m ³ annually, has the potential as a stable water resource in urban areas, and there are expectations for 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, basic water quality items to be noted include, in addition to the treated water quality required for the treated sewage water up to now, removal of the number of coliform bacteria, odor and chromaticity. Outside, BOD, pH, and turbidity are problems. In particular, in order to remove Escherichia coli, odor and chromaticity, a method of decomposing organic substances and inorganic substances by advanced treatment, for example, ozone treatment, can be 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). The three stimulus values include those in which the stimulus that the eye receives from the color mainly feel strongly in red, those in which it strongly feels in green, and those in which it strongly feels in blue-purple. 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 and obtained. Calculate by multiplying the value by a coefficient.

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, the above-mentioned platinum / cobalt method or JIS K 0102, which is generally adopted as a chromaticity measuring method in the reuse of sewage or waste water, is used.
The (single color display method) is not suitable for monitoring and controlling advanced treatment of sewage, etc. for the following reasons.

That is, 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. Especially 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, so mere colorimetry is not enough. It can be said that it is enough.

The other JIS method (monochromatic display method) can evaluate the color tone, but the visible light is 400 to 700 nm.
Since there is a need for data at intervals of 20 nm in the above range, there is a problem that the device becomes large in size for continuous measurement.

Especially, the chromaticity measuring device used for monitoring and controlling the use of sewage or wastewater as scenic water or hydrophilic water by an advanced treatment system requires automatic and continuous measurement. It is also possible to evaluate the color tone other than yellowish or yellowish brown. In addition, treated water that has been highly treated by ozone treatment, etc.
Although it is almost yellowish or yellowish brown, it is also necessary to evaluate other color tones because it is necessary to measure the chromaticity before advanced treatment for monitoring and control. When dyeing wastewater flows in, the above-mentioned color tone evaluation is highly necessary.

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.

[0021]

In order to achieve the above object, the present invention firstly proposes a wavelength 39 of sample water according to claim 1.
After measuring the absorbance at around 0 nm and calculating the chromaticity of the sample water from the calibration curve prepared with the chromaticity standard solution, the sample water was separately measured at one or more wavelengths within the visible light wavelength range. And a chromaticity measurement method for correcting the chromaticity of the sample water from the measured peak height of the absorbance at a specific wavelength.

Further, according to the present invention, a light source arranged with a condenser lens in one of the measuring cells into which the sample water flows, and a light receiving element arranged with a condenser lens in the other of the measuring cells. And a wavelength selection filter arranged between the light receiving element and the condenser lens for selecting a target wavelength from two or more wavelengths, and the absorbance at the selected specific wavelength is received as light receiving data of the light receiving element. Then, the chromaticity measuring device in the sewage or wastewater treatment comprises a calculation and control signal output section for calculating and correcting the chromaticity value by the calculating means.

[0023]

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. The light reception data of the device is input to the calculation and control signal output unit, and the chromaticity value is measured by calculation.

The chromaticity is measured by measuring the absorbance of the sample water near the wavelength of 390 nm and calculating the chromaticity of the sample water from the calibration curve prepared with the chromaticity standard solution. The absorbance at one or more wavelengths in the region is measured, and the chromaticity of the sample water is corrected by the peak height of the absorbance at the measured specific wavelength.

[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 configuration example of an automatic chromaticity measuring device,
Reference numeral 1 in the figure is a measuring cell, and condenser lenses 2 and 3 are arranged on both sides of the measuring cell 1. 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 in detail later, the wavelength selection filter 6 is based on the measurement of the absorbance around the wavelength of 390 nm, and the wavelength selection filter 6 has one or more wavelengths within the visible light wavelength range. It is for measuring the absorbance.

The outline of the operation when 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 and then turns 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. FIG. 2 shows the water supply test method 4. It is a graph which shows the result of having measured the light absorbency (E390) of wavelength 390nm with a 50 mm cell about the chromaticity standard liquid prepared for each chromaticity based on the platinum-cobalt method prescribed | regulated by the term of chromaticity. According to the figure, the chromaticity and the absorbance show a good correlation, and it was found that the chromaticity can be evaluated by the absorbance (E390) for the chromaticity standard solution.

FIG. 3 shows a chromaticity measurement value based on the platinum-cobalt method for an actual sample and a chromaticity measurement based on the transmitted light measurement method for calculating the chromaticity of sample water from a calibration curve prepared with a chromaticity standard solution. It is a graph comparing with the value. Specifically, sewage secondary treated water is subjected to ozone treatment under constant conditions, sample water is sampled at each ozone treatment time, and one is platinum / cobalt method (ratio 2) using the graph of FIG. 2 as a calibration curve, and the other graphs the results measured by the transmitted light measuring method at a wavelength of 390 nm for comparison.

From FIG. 3, the difference between the above two measuring methods is that
For example, it can be seen that when the chromaticity is 5 degrees or more and the ozone treatment time is 20 minutes or less, it is large.

In view of the above, FIG. 4 shows a wavelength 35 when the ozone treatment time is 20 minutes or less for the same actual sample water as in FIG.
It is the graph which showed the light absorption spectrum (Abs) of 0-800 nm. Further, FIG. 5 is a graph showing an absorbance spectrum of a chromaticity standard solution prepared at 1 to 20 degrees at a wavelength of 350 to 800 nm.

Comparing FIG. 4 and FIG. 5, in the absorbance spectrum of the chromaticity standard solution, the absorbance on the longer wavelength side than the wavelength of 550 nm is almost zero, while in the actual sample water, the wavelength is around 630 nm. It can be seen that there is a peak M of absorbance. This peak M is large on the high chromaticity side, and this is considered to be the cause of the difference in measured chromaticity between the platinum-cobalt method and the transmitted light measurement method shown in FIG.

FIG. 6 is a graph showing the relationship between the difference in chromaticity as a result of measurement by both measurement methods in FIG. 3 and the height of the absorbance peak M at the wavelength of 630 nm in FIG. It was found that the two are in a substantially linear relationship, and based on this, the value of the transmitted light measurement method shown in FIG. 3 can be corrected.

The graph of FIG. 7 shows the results of correcting the chromaticity measured by the platinum-cobalt method and the chromaticity measured by the transmitted light measuring method based on the above. According to FIG. 7, platinum
It can be seen that the chromaticity measurement result by the cobalt method and the chromaticity value by the corrected transmitted light measurement method are in good agreement.

It was observed visually that the above sample water was slightly bluish and pale yellow before the ozone treatment, but after 20 minutes of treatment, the bluish color disappeared to become a normal pale yellow. Therefore, it was confirmed that the above amendment is a rational method.

In addition to the bluish tint, the treated sewage water may have a reddish tint, and in that case, it is considered that correction at a wavelength corresponding to the reddish tint is effective. Therefore, as a method of satisfying the condition of chromaticity measurement in the monitoring and control of the advanced processing system in the present embodiment, the absorbance (transmitted light rate) around the wavelength of 390 nm is used.
The most suitable method is to measure the absorbance at another wavelength or two or more wavelengths in the visible light wavelength range and correct it based on the above measurement.

[0039]

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 correction means from the absorbance based on the light reception data of the light receiving element at the wavelength. Especially in the case of reuse of sewage or waste water, unlike the treatment of tap water, it is not enough to evaluate only yellowish or yellowish brown, and it is necessary to evaluate the chromaticity in the entire visible light range and distinguish the color tone. Therefore, the measuring method according to the present invention requires monitoring of advanced treatment of sewage, etc.
Suitable for control.

Further, objective measurement can be performed unlike the conventional colorimetric method by visual inspection with the naked eye.
Absorbance measurement data in the range of 0 to 700 nm can be continuously measured without increasing the size of the device, and it is yellowish.
Since it is possible to evaluate colors other than yellowish brown, it satisfies the requirements for monitoring and controlling advanced treatment of sewage, etc., and has a high correlation with the measurement by the platinum / cobalt method. It is possible to provide a chromaticity measuring method and apparatus that are also preferable from the viewpoint of sex.

[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 the absorbance (E39) of a chromaticity standard solution at a wavelength of 390 nm.
The graph which shows the result of having measured 0).

FIG. 3 is a graph comparing measured chromaticity values based on a platinum-cobalt method with actual samples and measured chromaticity values based on a transmitted light measurement method.

FIG. 4 is a graph showing an absorbance spectrum of an actual sample with respect to ozone treatment time.

FIG. 5 is a graph showing an absorbance spectrum of a chromaticity standard solution.

FIG. 6 is a graph showing the relationship between the chromaticity difference between the platinum-cobalt method and the transmitted light measurement method and the height of the peak of absorbance at a wavelength of 630 nm.

FIG. 7 is a graph showing the chromaticity measurement value by the platinum-cobalt method and the result of correcting the chromaticity measured by the transmitted light measurement method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Measurement 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 part 9 ... Floating matter removal filter 10 ... Sample water 12 ... Overflow tube

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Koichi Shimizu Inventor, Koichi Shimizu 2-1-117 Osaki, Shinagawa-ku, Tokyo

Claims (2)

[Claims] 1. The absorbance of the sample water near a wavelength of 390 nm is measured, and the chromaticity of the sample water is calculated from a calibration curve prepared with a chromaticity standard solution. Then, the sample water is separately measured in the visible light wavelength range. Chromaticity measurement in sewage or wastewater treatment, characterized by measuring the absorbance at one or more wavelengths and correcting the chromaticity of the sample water from the peak height of the absorbance at the measured specific wavelength. Method. 2. A light source arranged with a condenser lens on one side of a measuring cell into which sample water flows, a light receiving element arranged on the other side of the measurement cell with a condenser lens, and the light receiving element. A wavelength selection filter which is arranged between the element and the condenser lens and which selects a target wavelength from two or more wavelengths, and the absorbance at the selected specific wavelength is received as the light reception data of the light receiving element, and the calculation means Calculate the chromaticity value by
A chromaticity measuring device in sewage or wastewater treatment, which comprises a calculation and control signal output unit for correction.