KR102607667B1 - Method for measurement of turbidity - Google Patents

Abstract

The examples relate to methods for measuring turbidity.
Specifically, this measurement method is based on a scattered light method suitable for low concentration measurement among the methods of measuring tap water turbidity, and calculates the stray light correction equation for the low concentration section representing stray light characteristics in the turbidity measuring device to correct turbidity.
Therefore, by reducing the error in the low concentration range and measuring accurately, the quality of tap water is accurately diagnosed.

Description

Turbidity measurement method {Method for measurement of turbidity}

The content disclosed in this specification relates to a method of diagnosing water quality by measuring turbidity of tap water.

Unless otherwise indicated herein, the material described in this section is not prior art to the claims of this application, and is not admitted to be prior art by inclusion in this section.

Generally, residual chlorine or turbidity of tap water is used to diagnose tap water quality.

Among these, turbidity of tap water indicates the degree of cloudiness of the water. It contains suspended substances that interfere with the passage of light and cause scattering and absorption of light. Nephelometry measures the degree of scattering of turbid particles. Use a lot.

These measurement methods include scattered light, transmitted light, surface scattered light, and transmitted scattered light.

In particular, the scattered light method is known to be suitable for measuring low turbidity. In the scattered light method, the infrared light emitting device and the receiving device are installed at a 90° angle. Therefore, the light irradiated to the sample water is scattered by turbid particles, and the intensity of this scattered light is measured to measure turbidity.

However, measurement errors in scattered light occur due to the processing condition or contamination of the surface of the measuring unit, especially in the low concentration range, making accurate measurement difficult in actual water supply.

The prior art in this background is the following literature.

(Patent Document 0001) KR 200315453 B1

(Patent Document 0002) KR 100572370 B1

Document 1 above uses a laser diode as a light source to measure turbidity through the intensity of scattered light. Additionally, Document 2 measures low-concentration turbidity by simultaneously measuring the amount of light from the light source and the intensity of scattered light at two points.

The disclosed content is intended to provide a turbidity measurement method that accurately measures tap water turbidity by reducing errors in the low concentration range based on a scattered light method suitable for low concentration measurement.

The turbidity measurement method according to the example is,

First, using the existing scattered light method. Light is irradiated through a light source to tap water whose water quality is to be diagnosed, and turbidity is measured by detecting the intensity of scattered light with a detector attached at a 90-degree angle within a set distance from the light source.

In this case, stray light is generated due to the processing condition or contamination of the surface of the measuring part, causing errors, and it mainly occurs in low concentration areas.

Therefore, in the embodiment, a low concentration section showing these stray light characteristics is set for each turbidity measurement device, and the turbidity is corrected and accurately measured for each low concentration section through a stray light correction equation for the set low concentration section.

According to embodiments, among the methods of measuring tap water turbidity, based on a scattered light method suitable for low concentration measurement, errors are reduced in the low concentration section and accurately measured, thereby accurately diagnosing the quality of tap water.

1 and 2 are diagrams for conceptually explaining a turbidity measurement method according to an embodiment.
Figures 3 and 4 are diagrams for explaining turbidity measurement and stray light correction applied to the turbidity measurement method according to an embodiment.
Figure 5 is a diagram showing the overall system applied to the turbidity measurement method according to one embodiment.
Figure 6 is a block diagram showing the configuration of a control device applied to the turbidity measurement method according to an embodiment.
Figure 7 is a flow chart sequentially showing a turbidity measurement method according to an embodiment.
Figure 8 is a diagram showing the operation keys and screen applied to the turbidity measurement method according to an embodiment

1 and 2 are diagrams for conceptually explaining a turbidity measurement method according to an embodiment.

Specifically, Figure 1 is a diagram for explaining the operation of measuring turbidity through complex measurement equipment applied to this measurement method. For reference, this complex measuring equipment measures residual chlorine and turbidity, and Figure 2 is a diagram to explain the operation of measuring residual chlorine using this equipment.

As shown in Figures 1 and 2, the turbidity measurement method according to one embodiment is based on a scattered light method suitable for low concentration measurement among the methods of measuring tap water turbidity. Therefore, light is irradiated through a light source to the tap water whose water quality is to be diagnosed, the intensity of the scattered light is detected with a detector attached at a 90 degree angle within a set distance with respect to the light source, and the turbidity is measured in proportion to this.

In this case, stray light is generated due to the processing condition or contamination of the surface of the measuring part, causing errors, and it mainly occurs in low concentration areas.

Therefore, in one embodiment, a low concentration section showing these stray light characteristics is set for each turbidity measurement device, and the turbidity is corrected and accurately measured for each low concentration section through the stray light correction equation for the set low concentration section.

For reference, turbidity is the degree of cloudiness of water and measures the degree of scattering of turbid particles as it contains suspended substances that interfere with the passage of light and cause scattering and absorption of light. For example, the conventional nephelo method is used.

Accordingly, one embodiment accurately diagnoses the quality of tap water by reducing errors in the low concentration range based on a scattered light method suitable for low concentration measurement among the methods of measuring tap water turbidity.

Meanwhile, the complex measurement equipment applied to this measurement method is explained in detail.

The complex measurement equipment largely includes a turbidity measurement device, a residual chlorine measurement device, and a control device.

The turbidity measuring device irradiates light through a light source to tap water whose water quality is to be diagnosed, detects the intensity of scattered light with a detector attached at a 90-degree angle within a set distance with respect to the light source, and measures turbidity in proportion to this. In this state, the turbidity is corrected and accurately measured through the stray light correction equation for the low turbidity concentration section that represents the stray light characteristics for each turbidity measurement device.

The control device is individually connected to the residual chlorine measuring device or the turbidity measuring device to control the measurement operation and display each residual chlorine concentration or turbidity.

The residual chlorine measuring device is based on a rotating electrode method, and tap water whose water quality is to be diagnosed is positioned between a reference electrode and a rotating driving electrode with no pH compensation between pH 6 and 8. Therefore, the residual chlorine concentration is measured by the amount of diffusion current according to the potential difference between the reference electrode and the driving electrode during rotation.

Specifically, the driving electrode is driven through a semi-permanent motor to maintain a preset rotation speed, and a voltage is applied between the driving electrode and the reference electrode. Therefore, the amount of diffusion current generated through the reduction reaction of the driving electrode and the oxidation reaction of the reference electrode is detected, and the residual chlorine concentration is measured in proportion to this amount.

In particular, if an error in the pH sensor or a decrease in reaction speed performance occurs in the pH range of 7 to 8, it will greatly affect the measurement of residual chlorine. Therefore, it is operated independently without pH compensation and measures HOCl and OCl simultaneously to measure residual chlorine response. Increase speed and measurement accuracy. In this case, the rotating electrode method minimizes the effects of air bubbles and flow rate, providing highly reliable measurement values.

Therefore, in the embodiment, the concentration of residual chlorine in tap water is accurately measured by increasing the reaction rate of residual chlorine without pH compensation based on the rotating electrode method, and the quality of tap water is accurately diagnosed.

For reference, the background to this residual chlorine concentration is as follows.

Generally, chlorine is used to treat microorganisms such as pathogenic bacteria in tap water purification and sewage treatment.

Chlorine in water reacts with phenol or other organic substances, causing a specific odor, and its strong oxidizing power causes corrosion of related devices and supply pipes, so it is important to maintain an appropriate concentration of residual chlorine to suit the purpose, and continuous monitoring and maintenance are required. is needed.

In particular, in order to provide safe tap water, it is necessary to maintain a constant residual chlorine concentration from the chlorine injection process to the consumer. Conventionally, managers at water purification plants moved to a location where measuring equipment to measure residual chlorine concentration was installed and checked it several times or more every day.

However, continuous use of such equipment deteriorates sensor performance, lowering measurement accuracy, and making it quite difficult to check water quality in real time.

So, in order to solve this problem, the present applicant has filed an application for a 'residual chlorine measuring device with comparative measurement and self-calibration functions.'

Through this, the residual chlorine concentration is continuously measured, reagent costs are reduced, contamination that may occur on the electrode surface of the reagent-free residual chlorine meter is minimized, and the influence of external factors on tap water samples is significantly reduced.

In addition, the present applicant seeks to accurately measure residual chlorine without pH compensation. In other words, if an error in the pH sensor or a decrease in reaction speed performance occurs in the pH range of 7 to 8, it will have a significant impact on the residual chlorine measurement, so accurate residual chlorine measurement is performed without pH compensation.

Figures 3 and 4 are diagrams for explaining turbidity measurement and stray light correction applied to the turbidity measurement method according to an embodiment.

As shown in Figures 3 and 4, turbidity measurement according to one embodiment first radiates light to tap water through a specific light source, and detects the scattered light with a detector attached at a 90-degree angle within a set distance from the light source. The turbidity of tap water is measured by detecting the intensity.

In this case, the light source is a tungsten lamp with a wavelength range between 400 and 600 nm, and the sensor composed of a photodiode that measures scattering calculates the concentration of turbidity by amplifying the level of current and voltage detected from a specific resistance.

Specifically, the control device first fixes a collimator to the lower part of the light source and irradiates the darkroom measurement part. For reference, a collimator is a device in an optical device such as a spectroscope that places a slit at the focus of the objective lens to transform light entering through a narrow gap into parallel light.

Then, the intensity of scattered light generated when particles in the sample are struck by the irradiated light source is detected by the sensor.

However, in this case, measurement errors in scattered light occur due to the processing condition or contamination of the surface of the measurement unit, which is called stray light. Stray light causes errors in low concentration areas, making accurate measurements in actual water supplies difficult.

To solve this, one embodiment performs stray light correction. In other words, a stray light correction method is installed inside the turbidity measurement device, and errors in stray light are minimized through zero calibration and span calibration to achieve accurate measurement at low concentrations.

First, a turbidity low-concentration section representing stray light characteristics is set for each turbidity measurement device, and a specific stray light correction formula is set and registered for each set turbidity low-concentration section.

Next, it is determined whether the turbidity measured by the turbidity measuring device is within the turbidity low concentration range of the registered turbidity measuring device.

As a result of the above determination, if the determined turbidity is within the turbidity low concentration section of the corresponding turbidity measuring device, it is corrected and displayed using the relevant stray light correction formula, and if it is outside the turbidity low concentration section of the corresponding turbidity measuring device, the measurement information is displayed as is.

Therefore, this correction compensates for errors in the low concentration range and ensures accurate measurement.

In this case, the intensity of the scattered light is proportional to the average molecular weight and size of the particles, so the concentration of the substance contained in the solution is calculated by measuring the intensity of the scattered light.

Additionally, the stray light correction equation is created in a low concentration range of 0.015 to 0.3 NTU, for example, in the case of a turbidity measuring device as shown in FIG. 4.

Here, before stray light correction, it is 0.085 NTU (Nethelometric Paultity Unit), and when compared to the actual turbidity concentration of 0.015, it can be seen that there is an error.

The stray light correction equation is created as a linearization function by obtaining a nonlinear function representing nonlinear characteristics for turbidity concentration at 0.015 to 0.3 NTU and performing linear fitting with the relevant approximate polynomial function. The turbidity concentration represents the intensity of scattered light that is the output of the detector.

The linearization function calculates and applies a linear fitting coefficient that reduces errors in the nonlinear characteristics of the output, taking into account the characteristics and status of the measurement part in the detector, such as material, thickness, size, and performance.

In particular, it is made in the linear function form y = ax + b, where y is the turbidity concentration after correction, a is the linear fitting coefficient, x is the turbidity concentration before correction, and b is the correction constant.

In this case, the linear fitting coefficient and correction constant are created to fit each low concentration section by setting a low concentration section representing stray light characteristics for each turbidity measurement device.

The turbidity measuring device is largely divided into field use and portable use, and in the case of field use, the linear fitting coefficient is set to a lower value than that of portable use in the same situation. The actual value depends on the output nonlinear characteristics of the field turbidity measurement device.

These on-site turbidity measuring devices are further classified by function, such as swimming pools or water purification plants. In the case of a swimming pool, a lower value will be set in relatively the same situation than for other functions. For reference, the same applies to portable devices.

For example, in the case of a turbidity measuring device used in a water purification plant for field use as shown in FIG. 4, the linear fitting coefficient is set to a value of 0.05 to 3.05, and the correction constant is set to a value of 0.05 to 2.05. Preferably, the stray light correction equation is y=1.0182x-0.0689.

Through this, as shown in Figure 4, before stray light correction, the concentration was 0.085 NTU, but after correction, it was 0.015, which was the same as the actual turbidity concentration. This effect is equally obtained at 0.120, 0.260, 0.310, 0.360, and 0.560.

Meanwhile, this correction is equally applied to the calibration operation to perform accurate calibration. The calibration operation is intended to reduce measurement error in turbidity measurement.

First, 20 L of distilled water is injected at a rate of 200 mL/min and waited for the first stabilization time. When the first stabilization time has elapsed, a collimator is fixed to the bottom of the light source and irradiated to the dark room measurement unit. Then, the intensity of the scattered light generated by the irradiated light source hitting the particles in the sample is detected by a detector.

Next, it is determined whether the intensity of the detected scattered light is zero and whether or not to perform zero correction is determined.

As a result of the determination, if the intensity of the scattered light is zero, the set span correction is initiated, and if a different value is obtained, zero correction is repeatedly performed until the intensity is zero.

According to the above span correction, a turbid formazine solution diluted in 20 L of distilled water is injected to a level of 9 NTU to create a span solution, and 20 L of the span solution is injected at a rate of 200 mL/min and waited for the second stabilization time.

When the second stabilization time has elapsed, fix the collimator to the bottom of the light source again and irradiate it to the darkroom measurement section. Then, the intensity of the scattered light generated by the irradiated light source hitting the particles in the sample is detected by a detector.

Next, it is determined whether the turbidity corresponding to the intensity of the scattered light is within the low concentration section of the corresponding turbidity measuring device.

As a result of the above determination, only if the determined turbidity is within the low concentration range of the corresponding turbidity measuring device, it is corrected using the corresponding stray light correction formula.

In addition, it is determined whether the intensity of scattered light corresponding to the corrected turbidity corresponds to the span for a preset time.

As a result of the above determination, if the intensity of the scattered light corresponds to the span, an accuracy test is performed. In other cases, span correction is performed until the intensity of the scattered light corresponds to the span.

Additionally, the embodiment checks whether there is an abnormality when a measurement operation is performed according to this quality test and informs the manager.

First, when the measurement operation is started, it is determined whether the turbidity measured by the turbidity measuring device is within the low turbidity concentration range of the turbidity device.

As a result of the above determination, only if the determined turbidity is within the low concentration range of the corresponding turbidity measuring device, it is corrected using the corresponding stray light correction formula.

Then, the corrected turbidity is compared with a set reference value, or if it is outside the low concentration range, the corresponding turbidity is compared with the reference value, and if it is higher than the reference value, it is determined to be in an abnormal state and an alarm is notified to the manager. For example, alarm information is displayed or an alarm sound is output.

For reference, the above-mentioned accuracy test is as follows.

1) Repeatability and reaction speed

① Perform zero calibration and span calibration.

② Inject 20L of zero solution at a rate of 200mL/min and allow stabilization time for 10 minutes.

③ Record the measured value after 5 minutes of stabilization time.

④ Inject 20L of span solution at a rate of 200mL/min and allow 10 minutes to stabilize.

⑤ Record the measured value after 5 minutes of stabilization time.

⑥ Repeat measurements ②~⑤ 4 times.

⑦ The reaction speed is measured when the measured value begins to change after span injection.

⑧ After starting the reaction speed measurement, record the time to reach 90% of the measured value.

* When circulating the sample, discharge it to the outside for 10 minutes and then circulate it.

2) Linearity

① Perform zero calibration and span calibration.

② Inject 20L of zero solution at a rate of 200mL/min and allow stabilization time for 10 minutes.

③ Inject 20L of 30% Span solution at a rate of 200mL/min and allow stabilization time for 10 minutes.

④ After the stabilization time, record the measured values at 5-minute intervals (15, 20, 25 minutes).

⑤ Inject 20L of zero solution at a rate of 200mL/min and allow stabilization time for 10 minutes.

⑥ Inject 20L of 50% Span solution at a rate of 200mL/min and allow stabilization time for 10 minutes.

⑦ After the stabilization time, record the measured values at 5-minute intervals (15, 20, 25 minutes).

⑧ Inject 20L of zero solution at a rate of 200mL/min and allow stabilization time for 10 minutes.

⑨ Inject 20L of 80% Span solution at a rate of 200mL/min and allow stabilization time for 10 minutes.

⑩ After the stabilization time, record the measured values at 5-minute intervals (15, 20, 25 minutes).

3) Zero/span drift

① Perform zero calibration and span calibration.

② Inject 20L of zero solution at a rate of 200mL/min and allow stabilization time for 10 minutes.

③ Record the measured value after 5 minutes of stabilization time.

④ Inject 20L of span solution at a rate of 200mL/min and allow 10 minutes to stabilize.

⑤ Record the measured value after 5 minutes of stabilization time.

⑥ Circulate the zero solution for more than 2 hours.

⑦ Inject 20L of span solution at a rate of 200mL/min and allow 10 minutes to stabilize.

⑧ Record the measured value after 5 minutes of stabilization time.

⑨ Inject 20L of zero solution at a rate of 200mL/min and allow stabilization time for 10 minutes.

⑩ Record the measured value after 5 minutes of stabilization time.

* When circulating the sample, discharge it to the outside for 10 minutes and then circulate it.

Figure 5 is a diagram showing the overall system applied to the turbidity measurement method according to one embodiment.

As shown in FIG. 5, in the system according to one embodiment, complex measuring equipment 100 is fixedly installed at key points along the supply pipe leading from the water purification plant (A) to the customer, and measures the residual chlorine concentration and residual chlorine concentration of tap water. Turbidity is measured in real time at all times.

In addition, the management information processing device 200 receives the residual chlorine concentration and turbidity information from the complex measurement equipment 100 and monitors and manages it, and the manager terminal 300 receives this information from the management information processing device 200 and performs on-site monitoring. Take action quickly.

Additionally, the complex measurement equipment 100 has the following features.

First, the electrodes are maintained in a constant state at all times through surface contamination prevention and automatic cleaning of the driving electrode and the reference electrode and are operated without separate maintenance.

In addition, it is connected to the inlet part of the measurement tank to inject the sample and discharge the measured sample through the outlet part, and the drain part discharges and cleans the internal sample automatically or manually to clean the measurement tank. Therefore, it is used for collecting small amounts of samples and provides precise measurements over a long period of time without replacement of consumables.

For reference, the complex measuring equipment 100 is used in various places such as 1) drinking water, water purification process, domestic water, 2) water pipe network, village water supply, and small-scale water supply facilities.

Figure 6 is a block diagram showing the configuration of a control device applied to a method for measuring turbidity of tap water according to an embodiment.

As shown in FIG. 6, the control device 110 according to one embodiment includes a key signal input unit 111, a power supply unit 112, a measuring device connection unit 113, an analog output unit 114, a communication unit 115, It includes an external input unit 116, a relay output unit 117, a display unit 118, and a control unit 119.

The key signal input unit 111 receives various user setting information for measuring residual chlorine and turbidity according to an embodiment. For example, measurement target information and calibration information.

The power unit 112 is used to supply power to each unit.

The measuring device connection portion 113 is individually connected to a residual chlorine measuring device or a turbidity measuring device to receive residual chlorine concentration and turbidity information, respectively.

The analog output unit 114 has a plurality of channels. The first channel transmits residual chlorine information or turbidity information to surrounding registration control equipment, and the second channel transmits water temperature information in the same manner.

The communication unit 115 transmits the residual chlorine concentration information and water temperature information measured by the residual chlorine measurement device to the registration management information processing device 200 at a remote location, or transmits the turbidity information by the turbidity measurement device to the remote administrator. send to

The external input unit 116 is connected to various external sensing devices, etc.

The relay output unit 117 includes a first relay for cleaning the drain unit, a second relay for alarming when an abnormality occurs in each measurement value of the residual chlorine measuring device or the turbidity measuring device, and the first relay and the second relay. It is equipped with a third relay for relay selection. In this case, a manual relay for manual cleaning and alarm release is further included. Therefore, the control unit 119 compares the residual chlorine concentration value with a preset value and outputs an alarm through the second relay if it is abnormal. Additionally, the control unit 119 controls the discharge operation of the drain unit according to preset cleaning cycle information or preset cleaning time information for cleaning the measurement tank. This operation is also used for turbidity.

The display unit 118 displays residual chlorine concentration information and turbidity information measured under the control of the control unit 119.

The control unit 119 controls the power unit 112, the measuring device connection unit 113, the analog output unit 114, the communication unit 115, and the relay output unit 117 to accurately measure the residual chlorine concentration and turbidity. And, the transmission operations of the analog output unit 114 and the communication unit 115 are controlled respectively according to the calculated residual chlorine concentration value or turbidity concentration value.

Figure 7 is a flow chart sequentially showing a turbidity measurement method according to an embodiment.

As shown in FIG. 7, the turbidity measurement method according to one embodiment first connects a turbidity measuring device to a control device to measure the turbidity of tap water.

Light is irradiated to the tap water through a light source (S701), the intensity of scattered light is detected with a detector attached at a 90-degree angle within a set distance from the light source (S702), and turbidity is measured in proportion (S703). .

In this case, a turbidity low-concentration section representing stray light characteristics is set for each turbidity measuring device, and a stray light correction formula is registered for each set turbidity low-concentration section.

Next, it is determined whether the turbidity measured by the turbidity measuring device is within the low concentration range of the registered turbidity measuring device.

As a result of the above determination, if the determined turbidity is within the low concentration range of the corresponding turbidity measuring device, it is corrected using the corresponding stray light correction formula and measured accurately (S704). Then, the measurement results are displayed to the manager, and on the other hand, if the turbidity is outside the low concentration range of the turbidity measurement device, the measurement information is displayed as is (S705).

Next, to measure the residual chlorine concentration, a reference electrode is fixed in the residual chlorine measuring device, and tap water whose water quality is to be measured is placed between the driving electrode located at a certain distance. Therefore, pH is measured between 6 and 8 using the rotating electrode method through the above control device.

First, the driving electrode is driven through the semi-permanent motor described above to maintain a preset rotation speed (S711).

Then, a preset voltage is applied between the driving electrode and the reference electrode (S712).

Next, the amount of diffusion current generated through the reduction reaction of the driving electrode and the oxidation reaction of the reference electrode by the set voltage is detected (S713).

Therefore, residual chlorine proportional to the diffusion current amount is calculated (S714), and the calculated residual chlorine concentration is displayed (S715).

In particular, whenever this residual chlorine is measured, HOCl and OCl are measured collectively between pH 6 and 8.

As described above, one embodiment accurately diagnoses the quality of tap water by reducing errors in the low concentration range based on a scattered light method suitable for low concentration measurement among the methods of measuring tap water turbidity.

Additionally, the concentration of residual chlorine in tap water is accurately measured by increasing the reaction rate of residual chlorine without pH compensation based on the rotating electrode method, thereby accurately diagnosing the quality of tap water.

Figure 8 is a diagram showing operation keys and application screens applied to the turbidity measurement method according to an embodiment, respectively.

As shown in FIG. 8, the operation keys and application screen according to one embodiment correct the error in the low concentration section by performing stray light correction when the intensity of scattered light is measured through the turbidity measuring device, as described above. . Then, the turbidity concentration is calculated in proportion to this and an alarm is issued. This operation also applies to residual chlorine. For reference, various setting information is entered into the operation keys for this purpose. For example, measurement object, measurement information, calibration information, etc. Then, information for operating the drain section, etc. is input.

100: Complex measuring equipment (residual chlorine measuring device + control device)
200: Management information processing device
300: Administrator terminal

Claims (3)

Turbidity measuring device and control device using scattered light method; In the method of measuring turbidity by the control device controlling the turbidity measuring device,
A first step of setting and registering a stray light correction equation for a low concentration section representing stray light characteristics in the turbidity measuring device;
A second step of calculating the turbidity concentration using the intensity of scattered light of the sample water measured by the turbidity measuring device;
A third step of comparing the low concentration section registered in the first step with the turbidity concentration calculated in the second step;
In the third step, if the turbidity concentration of the second step falls within the low concentration range of the first step, a fourth step of correcting the turbidity concentration using the corresponding stray light correction method;
a fifth step of displaying the turbidity concentration corrected in the fourth step, or displaying the corresponding turbidity concentration if the turbidity concentration of the second step falls outside the low concentration section of the first step; and
A sixth step of sequentially performing zero calibration, span calibration, and accuracy testing on the turbidity measuring device;

The sixth step is
Step 6-1 of calculating the turbidity concentration by measuring the scattered light intensity of the light irradiated to the span solution by the turbidity measuring device;
A 6-2 step of comparing the low concentration section registered in the first step with the turbidity concentration calculated in the 6-1 step;
In step 6-2, if the turbidity concentration of step 6-1 falls within the low concentration range of step 1, a step 6-3 of correcting the turbidity concentration using the corresponding stray light correction formula;
Determine whether the intensity of the scattered light corresponding to the turbidity concentration corrected in step 6-3 spans, or if the turbidity concentration of step 6-1 falls outside the low concentration section of step 1, scattered light corresponding to the corresponding turbidity concentration Step 6-4 of determining whether the intensity spans; and
In step 6-4, a 6-5 step of starting the accuracy test when the intensity of the scattered light corresponding to the turbidity concentration is the span; a turbidity measurement method comprising a. delete In claim 1,
The stray light correction formula is
y = ax + b, where y is the turbidity concentration after correction, a is the linear fitting coefficient, A turbidity measurement method characterized in that.