JP7453702B2 - COD automatic measuring device - Google Patents

Description

The present invention relates to the amount of sample collected in COD and BOD analysis, an automatic BOD sample diluter, an automatic COD measuring device, and an automatic BOD measuring device.

JIS K 0102 stipulates a factory wastewater test method, and its 17 stipulates "oxygen consumption by potassium permanganate ( _CODMn ) at 100°C". Regarding COD analysis and COD automatic analyzers based on JIS K 0102 17, the following problems have been pointed out.

When hydroxylamine compounds (NS compounds) coexist in wastewater, it takes about one week to decompose the NS compounds (see, for example, Patent Document 1). The generated silver chloride adheres to various sensors such as the inner walls of the reaction tank and piping, and the oxidation-reduction potential (ORP) electrode in the reaction tank, resulting in errors in COD value measurement (see, for example, Patent Document 2). Furthermore, there are the following issues.

JP2008-76338A Japanese Patent Application Publication No. 2009-139119

Currently, in COD analysis, the amount of sample to be collected is determined by the analyst who visually predicts the COD value, such as the turbidity, color, and odor of the sample liquid, and if there is a previous analysis of the same sample, the actual value at that time, The amount to be collected is determined with reference to other items, such as the SS value of suspended solids. On the other hand, JIS K 0102 17 stipulates that the amount to be collected is ``an amount such that the residual amount of 5 mmol/L potassium permanganate solution after heating for 30 minutes is 4.5 to 6.5 mL.'' .

In the case of prediction based on human senses, if the prediction is incorrect and the amount of sampled is incorrect, the COD value cannot be analyzed correctly and it is necessary to adjust the amount of sampled and retest. Even if the predicted value is correct and the re-analysis is avoided, the validity of the COD value cannot be proven, and the analyst must perform the analysis again to confirm the COD analysis value. I have confirmation.

Regarding biochemical oxygen demand (BOD), there are regulations regarding the amount of sample to be collected in JIS K 0102, 21. Here, it says, ``The BOD value is calculated using the results of a diluted sample in which the amount of dissolved oxygen consumed during 5 days of culture is 40 to 70% of the amount before culture,'' and the dilution rate is important. I understand the gender.

Currently, the dilution rate of BOD is determined based on the five senses of the person in charge of analysis, the transparency of the sample liquid, etc. Also, the validity of whether the BOD value has been tested correctly is the same as that of COD.

As described above, although the amount of sample collected in COD and BOD analysis has a significant influence on the analysis results, no method or device for automatically collecting an appropriate amount of sample has been developed to date. Furthermore, no method has been developed to date to solve the question of whether the COD value and BOD value can be tested correctly.

An object of the present invention is to provide an automatic COD measuring device that can determine an appropriate sample amount for COD analysis and confirm the validity of the analysis results.

The present invention uses a UV spectrophotometer with a flow cell installed in the middle of a sample collection line to measure the absorbance of the sample , and a predicted COD value E _COD ( mg/L), formula (1), and formula (2) to determine the sample collection volume V (mL); A COD analyzer comprising an automatic sample collection means for sending , a reagent supply means, a reaction means comprising a heater and a reaction tank consisting of a water bath or a hot water bath, a titration means comprising a titrator and a detector for detecting an end point , and the UV absorption A photometer, the automatic sample collection means, and a control device that controls the operation of the COD analyzer according to the analysis procedure specified in the official method, and the control device is configured so that the sample is sent and the sample collection line is shared. The COD automatic measurement device is characterized in that the UV absorption photometer is controlled to measure absorbance during the washing process .
V=0.2×(a-b)×f×1000/E _COD ...(1)
a-b=4.5...(2)
However, when V≧100, V=100
Here, a-b is the median value (mL) of the titration value (titration amount - blank test value)
f is the factor of 5 mmol/L potassium permanganate solution

The automatic COD measurement device according to the present invention includes a data storage means for storing COD data in which the absorbance of the sample measured by the UV absorption photometer and the COD of the sample measured by the COD analyzer; a correction means for correcting the correlation between the absorbance of the sample obtained in advance and the COD using the COD data, and the sample collection amount determining means corrects the correlation between the corrected absorbance of the sample and the COD. The method is characterized in that the sample collection amount V is determined using the following.

According to the present invention, it is possible to provide an automatic COD measurement device that can determine an appropriate sample amount for COD analysis and support the validity of analysis results.

FIG. 3 is a diagram showing the procedure of the method for determining the amount of COD sample collected according to the first embodiment of the present invention and the relationship between the absorbance of the sample and COD. It is a figure which shows the procedure of the BOD sample collection amount determination method of 2nd Embodiment of this invention, and the relationship between the absorbance of a sample and BOD. It is a block diagram of the COD automatic measuring device 1 of 3rd Embodiment of this invention. It is a block diagram of the automatic diluter 100 of 4th Embodiment of this invention. It is a block diagram of the BOD automatic measuring device 2 of 5th Embodiment of this invention.

FIG. 1 is a diagram showing the procedure of the COD sample collection amount determining method according to the first embodiment of the present invention and the relationship between the absorbance of the sample and the COD. The method for determining the amount of COD sample to be collected according to the first embodiment of the present invention is based on the ``appropriate amount of sample is 30 _min . This is a method for determining the amount of sample to be collected in order to achieve a residual amount of 5 mmol/L potassium permanganate solution after heating of 4.5 to 6.5 mL, as shown in Figure 1 (A). a step (A1) of measuring the absorbance of the sample, and a step (A2) of determining the sample collection amount V (mL) from the predicted COD value E _COD (mg/L) of the sample and equations (1) and (2). ) and including.

Hereinafter, the method specified in JIS K 0102 17 "Oxygen consumption by potassium permanganate at 100°C ( _CODMn )" will be used as the official method, and the method specified in the official method as "The appropriate amount of sample should be heated for 30 minutes. The appropriate amount of the sample for the official method is defined as "an amount such that the remaining amount of 5 mmol/L potassium permanganate solution is 4.5 to 6.5 mL."

To measure the absorbance of the sample in step (A1), a UV absorption photometer is used to irradiate the sample with light at a wavelength of 254 nm and measure the absorbance. The UV absorption photometer and the absorbance measurement method are not particularly limited, and any known UV absorption photometer and measurement method can be used.

In step (A2), the sample collection amount V (mL) is determined from the predicted COD value E _COD (mg/L) of the sample and equations (1) and (2). The predicted COD value E _COD (mg/L) of the sample is calculated using the absorbance of the sample measured in step (A1) and the correlation between the absorbance of the sample and COD obtained in advance. An example of this correlation is shown in FIG. 1(B).

The horizontal and vertical axes in FIG. 1(B) are the absorbance of the sample measured with light at a wavelength of 254 nm using a UV absorption photometer, and the COD (mg/L) obtained by analyzing the sample using the official method. FIG. 1(B) is a plot of the absorbance and COD obtained by measuring a plurality of samples, and it can be seen that the COD is directly proportional to the absorbance. This is the correlation between the absorbance and COD of the sample obtained in advance, and by applying the absorbance X obtained in step (A1) to the above correlation, the predicted COD value E _COD (mg/L) of the sample can be obtained. It will be done. The correlation between the absorbance of the sample and the COD can be expressed by a correlation equation as shown in FIG. 1(B), but may be expressed by other methods.

In Figure 1 (B), the absorbance and COD of the samples were obtained and plotted using samples with different types of wastewater and discharge locations. The correlation between absorbance and COD may be derived for each specific sample, such as wastewater discharged from the same location. By deriving the correlation between the absorbance and COD of a specific sample and using the correlation corresponding to that sample, a highly accurate predicted COD value E _COD (mg/L) can be obtained. Alternatively, a simulated sample may be prepared using a standard substance, and a correlation between absorbance and COD may be obtained from the simulated sample.

Equations (1) and (2) are equations for calculating the sample collection amount V (mL) based on the predicted COD value E _COD (mg/L) of the sample, and are as follows. Equations (1) and (2) are also shown in official methods.
V=0.2×(a-b)×f×1000/E _COD ...(1)
a-b=4.5...(2)
However, when V≧100, V=100
Here, a-b is the median value (mL) of the titration value (titration amount - blank test value)
f is the factor of 5 mmol/L potassium permanganate solution

The basis for ab in formula (2) is as follows. According to the official method, add 10 mL of 5 mmol/L potassium permanganate solution to the sample and heat it for 30 minutes in an amount such that the remaining amount of 5 mmol/L potassium permanganate solution is 4.5 to 6.5 mL. Since it is said that is the appropriate amount of the sample, the consumption amount (titration value) of the 5 mmol/L potassium permanganate solution at this time will be 3.5 to 5.5 mL. a-b is the median consumption (titration value) of 4.5 mL.

As described above, the method for determining the amount of COD sample collected according to the first embodiment of the present invention is based on the absorbance of the sample measured with light at a wavelength of 254 nm using a UV absorption photometer and the COD ( This method utilizes the fact that there is a correlation between COD (mg/L) and obtains the predicted COD value E _COD (mg/L) of the sample from this to determine the amount of sample to be collected.

FIG. 2 is a diagram showing the procedure of the BOD sample collection amount determination method according to the second embodiment of the present invention and the relationship between the absorbance of the sample and the BOD. The method for determining the amount of BOD sample collected according to the second embodiment of the present invention is based on the method for determining the amount of diluted sample to obtain the normal BOD of the sample specified in JIS K 0102 21 “Biochemical Oxygen Consumption (BOD)”. This is a method for determining the amount of sample to be collected to achieve ``oxygen consumption (D ₁ - D ₂ ) is in the range of O 3.6 to 6.4 mg/L,'' as shown in Figure 2 (A). A step (B1) of measuring the absorbance of the sample, and a step (B2) of determining the sample collection amount V (mL) from the predicted BOD value E _BOD (mg/L) of the sample and equations (3) and (4). and, including.

Hereinafter, the method specified in JIS K 0102 21 "Biochemical oxygen consumption (BOD)" will be used as the official method, and the method specified in the official method as "dissolved oxygen consumption of a diluted sample to obtain a normal BOD of the sample" will be used. The appropriate amount of the sample that satisfies the condition "The amount (D ₁ - D ₂ ) is in the range of 3.6 to 6.4 mg/L" is referred to as the appropriate amount of the sample according to the official method.

To measure the absorbance of the sample in step (B1), a UV absorption photometer is used to irradiate the sample with light at a wavelength of 254 nm and measure the absorbance. The UV absorption photometer and the absorbance measurement method are not particularly limited, and any known UV absorption photometer and measurement method can be used.

In step (B2), the sample collection amount V (mL) is determined from the predicted BOD value E _BOD (mg/L) of the sample and equations (3) and (4). The predicted BOD value E _BOD (mg/L) of the sample is calculated using the absorbance of the sample measured in step (B1) and the correlation between the absorbance of the sample and BOD obtained in advance. An example of this correlation is shown in FIG. 2(B).

The horizontal and vertical axes in FIG. 2(B) are the absorbance of the sample measured with light at a wavelength of 254 nm using a UV absorption photometer, and the BOD (mg/L) obtained by analyzing the sample using the official method. FIG. 2(B) is a plot of absorbance and BOD obtained by measuring a plurality of samples, and it can be seen that BOD is directly proportional to absorbance. This is the correlation between the sample absorbance and BOD obtained in advance, and by applying the absorbance X obtained in step (B1) to the previous correlation, the predicted BOD value E _BOD (mg/L) of the sample can be obtained. It will be done. The correlation between the absorbance of the sample and the BOD can be expressed by a correlation equation as shown in FIG. 2(B), but may be expressed by other methods.

In Figure 2 (B), the absorbance and BOD of the samples were obtained and plotted using samples with different types of wastewater and discharge locations. A correlation between absorbance and BOD for each specific sample, such as wastewater discharged from the same location, may be derived. By deriving the correlation between the absorbance and BOD of a specific sample and using the correlation corresponding to that sample, a highly accurate predicted BOD value E _BOD (mg/L) can be obtained. Alternatively, a simulated sample may be prepared using a standard substance, and a correlation between absorbance and BOD may be obtained from the simulated sample.

Equations (3) and (4) are equations for calculating the sample collection amount V (mL) based on the predicted BOD value E _BOD (mg/L) of the sample, and are as follows. Equations (3) and (4) are also shown in official methods.
V=A×v/E _BOD ...(3)
A=5.0...(4)
Here, A is the median value (mg/L) of dissolved oxygen consumption (D ₁ - D ₂ ) of the diluted sample.
v is the volume of diluted sample (mL)

The basis for A in formula (4) is as follows. According to the official method, the consumption amount of dissolved oxygen (D ₁ - D ₂ ) of a diluted sample to obtain a normal BOD of the sample is in the range of 3.6 to 6.4 mg/L. The median value of dissolved oxygen consumption (D ₁ - D ₂ ) is 5.0 mg/L. A is the median dissolved oxygen consumption (D ₁ -D ₂ ) of this diluted sample, 5.0 mg/L.

As described above, the method for determining the amount of BOD sample collected according to the second embodiment of the present invention is based on the absorbance of a sample measured with light at a wavelength of 254 nm using a UV absorption photometer and the BOD ( This method uses the fact that there is a correlation between E BOD (mg/L) and obtains the predicted BOD value E _BOD (mg/L) of the sample from this to determine the amount of sample to be collected. The technical concept is the same as the COD sample collection amount determination method of the embodiment.

FIG. 3 is a configuration diagram of a COD automatic measuring device 1 according to a third embodiment of the present invention, in which FIG. 3(A) is an overall configuration diagram, and FIG. 3(B) is a functional configuration diagram of a control device 70. The automatic COD measurement device 1 includes a sample collection device 10 that automatically collects an appropriate amount of a sample according to an official method and sends it to a COD analysis device 50, and a COD analysis device 50 that measures the COD of the sample.

The sample collection device 10 includes a sample collection line 12 that sends a sample to the COD analyzer 50. A UV absorption photometer 18 into which a flow cell is inserted for measurement, and a preparative burette 20 for dispensing a determined sample amount are provided. The sample collecting device 10 is connected to a control device 70 so as to be able to transmit and receive data, and the control device 70 controls the operation.

The COD analyzer 50 is a COD analyzer having a configuration compliant with the official method, and includes a reagent storage tank 53 for storing reagents, and a reagent supply means 52 that automatically collects a certain amount of the reagent to be stored and supplies it to the reaction tank 56. , a reaction tank 56, a reaction means 55 comprising a heater 57 consisting of a water bath or an oil bath for heating the reaction tank 56, a titration means 60 comprising a titrator 62 and a detector 63 for detecting the end point, and a titration means 60 for processing data and for each device. - Equipped with a control means 70 that controls the operation of the device. In addition to the above-mentioned means, the COD analyzer 50 also includes cleaning means for cleaning the reaction tank 56 and the like, a waste liquid tank for storing waste liquid, and the like.

The control device 70 includes a data transmitting/receiving means 71 that connects to each device/equipment so as to be able to transmit and receive data, an input means 72 such as a touch panel or CD reader for inputting data, and an output means 73 such as a display or printer for outputting data. , a storage means 74 for storing various data and programs, a control means 75 for controlling each means, and a data processing means 76 for processing data.

The storage means 74 stores a program for collecting an appropriate amount of sample specified by the official method, a program for operating each device/means of the COD analyzer 50 according to the analysis procedure specified by the official method, and a program for calculating COD. Data processing programs such as are installed. The program for collecting the appropriate amount of sample specified in the official method is a program of the COD sample collection amount determining method according to the first embodiment of the present invention, and includes a correlation equation between the absorbance of the sample and COD, and It includes Equation (1) and Equation (2).

The control device 70 having the above configuration is realized by a computer in which the program is installed, a programmable logic controller, and peripheral devices such as a display.

The operation of the COD automatic measuring device 1 of the third embodiment will be explained. The control device 70 operates the sample collection device 10 and controls it to collect an appropriate amount of the official method sample. Specifically, the control device 70 transmits a wavelength of 254 nm to the UV absorption photometer 18 in the process of sending the sample from the autosampler 14 to the COD analyzer 50 and cleaning the sample collection line 12, which is performed prior to sample collection. Issue a command to measure the absorbance of the sample using the light of Upon receiving the command, the UV absorption photometer 18 measures the absorbance of the sample and sends the measured value to the control device 70.

The control device 70 uses the absorbance data from the UV spectrophotometer 18 and the program for collecting the appropriate amount of the official method sample stored in the storage means 74 to determine the appropriate amount of the sample and divide the amount into portions. The preparative burette 20 is controlled to collect the sample. The preparative buret 20 collects an appropriate amount of sample and sends it to the COD analyzer 50.

Subsequently, the control device 70 reads a program for operating each device/means of the COD analyzer 50 according to the analysis procedure prescribed in the official method stored in the storage means 74, and reads out a program for operating each device/means of the COD analyzer 50 according to the analysis procedure prescribed in the official method. Each device/means of the COD analyzer 50 is operated according to the following. An outline of the operation of the COD analyzer 50 is as follows.

The control device 70 controls the reaction means 55 and the reagent supply means 52 to add an appropriate amount of water to the sample sent from the sample collecting device 10, add a predetermined amount of sulfuric acid, and add a predetermined silver nitrate solution while stirring. and mask chloride ions in the sample. Subsequently, a predetermined potassium permanganate solution is added, stirred, and the reaction means 55 and reagent supply means 52 are controlled so that the reaction tank 56 is immediately heated with a heater 57 for 30 minutes.

Next, the control device 70 takes out the reaction tank 56 from the heater 57, adds a predetermined amount of sodium oxalate, stirs it, controls the reaction means 55 and the reagent supply means 52 to cause a reaction, and then increases the liquid temperature to 50 to 60°C. The titration means 60 is controlled to titrate with a predetermined potassium permanganate solution at . Separately, perform the same operation for water. The obtained results are processed by the data processing means 76 and the measurement results are outputted to the output means 73.

In the COD automatic measurement device 1 of the third embodiment having the above configuration, the sample collection device 10 automatically collects an appropriate amount of a sample according to the official method based on the absorbance measured by the UV absorption photometer 18, and the COD analyzer 50 automatically collects an appropriate amount of the sample according to the official method. Since the analysis is conducted in accordance with the law, an appropriate amount of sample can be collected for COD analysis, and the validity of the analysis results can be confirmed.

Next, a first modification of the automatic COD measuring device 1 of the third embodiment will be described. In the first modification, the control device 70 includes a COD database 81 that records data in which absorbance and COD are linked (hereinafter referred to as COD data) in the storage unit 74, and a data correction unit 82 in the data processing unit 76. The data correction means 82 is for correcting the correlation equation between the absorbance of the sample and the COD in the program for collecting an appropriate amount of the sample of the official method inputted in advance. Control device 70 operates as follows.

When the COD measurement of the sample by the COD analyzer 50 is completed, the control device 70 links the absorbance measured by the UV absorption photometer 18 and the COD measured by the COD analyzer 50, sets this as COD data, and stores it in the COD database. Recorded in 81. Further, the control device 70 periodically operates the data correction means 82 to read out COD data from the COD database 81, take in the data, and correct the correlation equation between the absorbance of the sample and the COD. After the correlation equation between absorbance and COD is corrected, the data processing means 76 determines the appropriate amount of sample for the official method based on the corrected correlation equation.

Next, a second modification of the COD automatic measuring device 1 of the third embodiment will be shown. In the second modification, similarly to the first modification, the storage means 74 of the control device 70 is provided with a COD database 81, and the data processing means 76 is provided with a data correction means 82.

Prior to sample collection and COD measurement, the control device 70 displays a request for input of the sample name to be analyzed on the output means 73, and after the sample name is input via the input means 72, the sample collection device 10 and the COD analyzer 50 are operated. When the measurement of the COD of the sample is completed, the control device 70 links the sample name, the absorbance measured by the UV absorption photometer 18, and the COD measured by the COD analyzer 50, sets this as COD data, and stores it in the COD database. Recorded in 81.

Further, the control device 70 periodically operates the data correction means 82 to read COD data from the COD database 81, take in data corresponding to each sample, and create or correct a correlation equation between absorbance and COD for each sample. After the correlation equation between absorbance and COD is corrected, the data processing means 76 determines the appropriate amount of the sample according to the official method based on the correlation equation corresponding to the sample.

The first modification of the automatic COD measuring device 1 of the third embodiment accumulates COD data, uses the data to review the correlation equation between the absorbance of the sample and the COD, and the automatic COD measuring device 1 of the third embodiment The second modification of the measuring device 1 accumulates COD data for each sample, and uses the data to review or create a correlation equation between the absorbance and COD for each sample, making it possible to collect an appropriate amount of a highly accurate sample. It is possible to confirm the validity of the analysis results.

The COD automatic measuring device according to the present invention has been described above using the COD automatic measuring device 1 of the third embodiment, the first modified example, and the second modified example. It is not limited to the form. The COD analyzer 50 of the automatic COD measuring device according to the present invention may have other configurations as long as the official method can be implemented.

In the COD automatic measuring device 1 of the third embodiment, the control device 70 is incorporated in the COD analyzer 50, but the control device 70 may be separated from the COD analyzer 50 and made independent, or it may be a part of the control device 70. may be separated from the COD analyzer 50 and made independent. Further, a control device for sample collection may be separately provided in the sample collection device 10, and the control device 70 may be mainly in charge of the COD analyzer 50.

The sample collection device 10 (including control means) constituting the automatic COD measurement device 1 of the third embodiment includes means for determining the appropriate amount of sample according to the official method, and automatically collecting the determined sample and sending it to the COD analyzer 50. It can be said that it consists of a means for discharging liquid. Therefore, the means (including control means) for determining the appropriate amount of sample in the former official method may be an independent sample collection amount determining device. By incorporating such a device into an existing COD analyzer, an automatic COD measuring device according to the present invention can be obtained.

FIG. 4 is a block diagram of an automatic diluter 100 according to a fourth embodiment of the present invention, in which FIG. 4(A) is an overall block diagram and FIG. 4(B) is a functional block diagram of a control device 165. The automatic diluter 100 is a device for preparing a diluted sample for BOD measurement, and includes a UV absorption photometer 118 that measures the absorbance of the sample, an automatic sample collection means 111 that collects an appropriate amount of the sample according to the official method, and a sample The apparatus includes a sample preparation means 130 for adding dilution water to prepare a predetermined diluted sample, and a control device 165 for connecting to each device and device and controlling their operations. The dilution water is as specified in the official method. In addition, if sample pretreatment is required or if inoculum dilution water is used, prepare each method according to official methods and perform operations according to official methods.

The control device 165 includes a data transmitting/receiving means 171 that connects each device/apparatus so as to be able to transmit and receive data, an input means 172 such as a touch panel or CD reader for inputting data, and an output means 173 such as a display or printer for outputting data. , a storage means 174 for storing various data and programs, a control means 175 for controlling each means, and a data processing means 176 for processing data.

The storage means 174 is installed with a program for collecting an appropriate amount of a sample specified by the official method and a program for preparing diluted samples with different dilution ratios in stages. The program for collecting the appropriate amount of sample specified in the official method is a program of the method for determining the amount of BOD sample collected according to the second embodiment of the present invention, and includes a correlation formula between the absorbance of the sample and BOD, and It includes equations (3) and (4).

The control device 165 having the above configuration is realized by a computer in which the program is installed, a programmable logic controller, and peripheral devices such as a display.

The UV absorption photometer 118 receives a command from the control device 165, measures the absorbance of the sample using light with a wavelength of 254 nm, and sends the measured value to the control device 165. The control device 165 uses the absorbance data from the UV spectrophotometer 118 and the program for collecting the appropriate amount of the sample according to the official method stored in the storage means 174 to determine the appropriate amount of the sample.

The automatic sample collection means 111 receives a command from the control device 165 and collects an appropriate amount of sample. The diluted sample preparation means 130 adds dilution water to the collected sample and stirs it to prepare a diluted sample, and further adds dilution water to a part of the diluted sample and stirs it to prepare diluted samples with different dilution ratios in stages. do.

In the automatic diluter 100 of the fourth embodiment having the above configuration, the automatic sample collection means 111 automatically collects an appropriate amount of the sample according to the official method based on the absorbance measured by the UV absorption photometer 118, and the diluted sample preparation means 130 automatically collects an appropriate amount of the sample according to the official method. Since diluted samples with different dilution ratios are prepared in stages, it is possible to collect an appropriate amount of sample for BOD analysis, and the validity of the analysis results can be verified.

The automatic diluter 100 of the fourth embodiment includes means for determining an appropriate amount of a sample using an official method, means for automatically collecting the determined sample, and means for diluting the sample to prepare a diluted sample. It can be said. Therefore, the means (including control means) for determining the appropriate amount of sample in the former official method may be an independent sample collection amount determining device. By incorporating such a device into an existing automatic diluter, the automatic diluter according to the present invention can be obtained.

FIG. 5 is a block diagram of a BOD automatic measuring device 2 according to a fifth embodiment of the present invention, in which FIG. 5(A) is an overall block diagram and FIG. 5(B) is a functional block diagram of a control device 170. The same components as the automatic diluter 100 according to the fourth embodiment of the present invention shown in FIG. 4 are given the same reference numerals, and the description thereof will be omitted. The automatic BOD measurement device 2 is a device that automatically collects an appropriate amount of a sample using the official method, adds dilution water to the sample to prepare a diluted sample, and analyzes BOD according to the official method. It includes a device 150 and a control device 170.

The automatic diluter 100 of the BOD automatic measuring device 2 according to the fifth embodiment has the same basic configuration as the automatic diluter 100 according to the fourth embodiment of the present invention. In the BOD automatic measurement device 2 of the fifth embodiment, the control device 170 controls the automatic dilution device 100. When sample pretreatment is required and when inoculum dilution water is used, each means is prepared according to the official method and operations are performed according to the official method, as in the automatic diluter 100.

The BOD analyzer 150 is a BOD analyzer having a configuration compliant with the official method, and includes a thermostat 157 that maintains a sealed flan bottle filled with a diluted sample at a predetermined temperature, and a storage stocker that stores the flan bottle. , a culture means 155 including means for extracting and transporting the flan bottle, a stopper opening/closing means for opening and closing the stopper of the flan bottle, and a DO measurement means 160 for measuring dissolved oxygen in the diluted sample.

The control device 170 includes a data transmitting/receiving means 171 that connects each device/apparatus so that data can be transmitted and received, an input means 172 such as a touch panel or CD reader for inputting data, and an output means 173 such as a display or printer for outputting data. , a storage means 174 for storing various data and programs, a control means 175 for controlling each means, and a data processing means 176 for processing data.

The storage means 174 stores a program for collecting an appropriate amount of sample specified by the official method, a program for operating each device/means of the BOD analyzer 150 in accordance with the analysis procedure specified by the official method, and a program for calculating BOD. and other data processing programs are installed. The program for collecting the appropriate amount of sample specified in the official method is a program of the method for determining the amount of BOD sample collected according to the second embodiment of the present invention, and includes a correlation formula between the absorbance of the sample and BOD, and It includes equations (3) and (4).

The control device 170 having the above configuration is realized by a computer in which the program is installed, a programmable logic controller, and peripheral devices such as a display.

The operation of the BOD automatic measuring device 2 of the fifth embodiment will be explained. The control device 170 controls the automatic diluter 100 to operate, collect an appropriate amount of the official method sample, and then prepare a diluted sample.

Specifically, the UV absorption photometer 118 receives a command from the control device 170, measures the absorbance of the sample using light with a wavelength of 254 nm, and sends the measured value to the control device 170. The control device 170 uses the absorbance data from the UV absorption photometer 118 and the program for collecting the appropriate amount of the official method sample stored in the storage means 174 to determine the appropriate amount of the sample, and uses the automatic sample collection means. An order is issued to 111 to collect an appropriate amount of sample. Subsequently, the control device 170 controls the diluted sample preparation means 130 to add dilution water to the collected sample, stir it, prepare a diluted sample, and fill it into a flan bottle.

Subsequently, the control device 170 reads a program for operating each device/means of the BOD analyzer 150 according to the analysis procedure prescribed in the official method stored in the storage means 174, and reads out a program for operating each device/means of the BOD analyzer 150 according to the analysis procedure prescribed in the official method. Each device/means of the BOD analyzer 150 is operated according to the following. An outline of the operation of the BOD analyzer 150 is as follows.

The control device 170 controls the DO measurement means 160 to measure dissolved oxygen 15 minutes after preparation of the diluted sample, and records the measured value in the storage means 174. The flan bottle filled with the diluted sample and sealed tightly is stored in a storage stocker and cultured for 5 days in the incubator 157 under predetermined conditions, and then the dissolved oxygen of the diluted sample is measured and recorded in the storage means 174. The obtained results are processed by the data processing means 176 and the measurement results are outputted to the output means 173.

In the BOD automatic measurement device 2 of the fifth embodiment having the above configuration, the automatic dilution device 100 automatically collects an appropriate amount of the sample of the official method based on the absorbance measured by the UV absorption photometer 118, and dilutes it with dilution water. Since diluted samples with different dilution ratios are prepared stepwise and analyzed by the BOD analyzer 150 according to the official method, it is possible to collect an appropriate amount of sample for BOD analysis, and to confirm the validity of the analysis results.

Next, a first modification of the BOD automatic measuring device 2 of the fifth embodiment will be described. In the first modification, the control device 170 includes a BOD database 181 that records data in which absorbance and BOD are linked (hereinafter referred to as BOD data) in a storage unit 174, and a data correction unit 182 in the data processing unit 176. The data correction means 182 is for correcting the correlation equation between the absorbance of the sample and the BOD in the program for collecting an appropriate amount of the sample of the official method inputted in advance. Control device 170 operates as follows.

When the measurement of the BOD of the sample by the BOD analyzer 150 is completed, the control device 170 links the absorbance measured by the UV absorption photometer 118 and the BOD measured by the BOD analyzer 150, sets this as BOD data, and stores it in the BOD database. 181. In addition, the control device 170 periodically operates the data correction means 182 to read BOD data from the BOD database 181, take in the data, and correct the correlation equation between the absorbance of the sample and the BOD. After the correlation equation between absorbance and BOD is corrected, the data processing means 176 determines the appropriate amount of sample for the official method based on the corrected correlation equation.

Next, a second modification of the BOD automatic measuring device 2 of the fifth embodiment will be shown. In the second modification, the storage means 174 of the control device 170 includes a BOD database 181, and the data processing means 176 includes a data correction means 182, as in the first modification.

Prior to sample collection and BOD measurement, the control device 170 displays on the output means 173 a request to input the name of the sample to be analyzed, and after the sample name is input via the input means 172, the automatic diluter 100 and BOD analyzer 150 are operated. When the measurement of the BOD of the sample is completed, the control device 170 links the sample name, the absorbance measured by the UV absorption photometer 118, and the BOD measured by the BOD analyzer 150, sets this as BOD data, and stores it in the BOD database. 181.

In addition, the control device 170 periodically operates the data correction means 182, reads BOD data from the BOD database 181, takes in data corresponding to each sample, and creates or corrects a correlation equation between the absorbance and BOD for each sample. After the correlation equation between absorbance and BOD is corrected, the data processing means 176 determines the appropriate amount of the sample according to the official method based on the correlation equation corresponding to the sample.

A first modification of the BOD automatic measuring device 2 of the fifth embodiment accumulates BOD data, uses the data to review the correlation equation between the absorbance of the sample and BOD, and also In the second modification of 2, BOD data is accumulated for each sample, and the correlation formula between absorbance and BOD for each sample is reviewed or created using the data, so that accurate collection of an appropriate amount of sample can be achieved. , and can support the validity of the analysis results.

The BOD automatic measuring device according to the present invention has been described above using the BOD automatic measuring device 2 of the fifth embodiment, the first modified example, and the second modified example. It is not limited to the form. The BOD analyzer 150 of the BOD automatic measuring device according to the present invention may have other configurations as long as the official method can be implemented. Furthermore, the configuration of the control device 170 is not limited to the above embodiment.

As mentioned above, the preferred embodiments have been described with reference to the drawings, but those skilled in the art will easily assume various changes and modifications within the obvious range after viewing this specification. It is therefore construed that such changes and modifications are within the scope of the invention as defined by the claims.

1 COD automatic measurement device 2 BOD automatic measurement device 10 Sample collection device 12 Sample collection line 18 UV absorption photometer 50 COD analysis device 70 Control device 81 COD database 82 Data correction means 100 Automatic dilution device 111 Automatic sample collection means 118 UV absorption light intensity Total 130 Diluted sample preparation means 150 BOD analyzer 155 Culture means 157 Incubator 160 DO measurement means 165 Control device 170 Control device 181 BOD database 182 Data correction means

Claims (2)

A UV absorption photometer with a flow cell installed in the middle of the sample collection line to measure the absorbance of the sample ;
Determine the sample collection amount V (mL) from the predicted COD value E _COD (mg/L) of the sample calculated using the correlation between the absorbance of the sample and COD, and equations (1) and (2). A sample collection amount determining means;
automatic sample collection means for collecting the determined sample collection amount V and sending it to the COD analyzer;
A COD analyzer comprising a reagent supply means, a reaction means comprising a heater and a reaction tank consisting of a water bath or a hot water bath, a titration means comprising a titrator and a detector for detecting an end point;
a control device that controls the operation of the UV absorption photometer, the automatic sample collection means, and the COD analyzer according to the analysis procedure specified in the official method ;
Equipped with
The automatic COD measurement device is characterized in that the control device controls the UV absorption photometer to measure absorbance during a process in which a sample is sent and the sample collection line is co-washed .
V=0.2×(a-b)×f×1000/E _COD ...(1)
a-b=4.5...(2)
However, when V≧100, V=100
Here, a-b is the median value (mL) of the titration value (titration amount - blank test value)
f is the factor of 5 mmol/L potassium permanganate solution a data storage means for storing COD data in which the absorbance of the sample measured by the UV absorption photometer and the COD of the sample measured by the COD analyzer are linked;
a correction means for correcting the correlation between the absorbance of the sample obtained in advance and the COD using the COD data;
Equipped with
2. The automatic COD measuring device according to claim 1 , wherein the sample collection amount determination means determines the sample collection amount V using a correlation between the corrected absorbance of the sample and the COD.

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