Dissolved oxygen consumption measuring device and dissolved oxygen consumption measuring method

Abstract

There is a need for a dissolved oxygen consumption rate measuring device that can predict BOD with little error. [Solution] A dissolved oxygen consumption measuring device comprising a container for holding liquid, a dissolved oxygen sensor, a nozzle for supplying air, an arm that operates to insert the dissolved oxygen sensor and the nozzle into the container, and a lid that is attached to the container to make it airtight and has an insertion portion into the container, wherein the operation of the arm causes the liquid in the container to overflow, and when the lid is attached, the liquid in the container overflows further and the underside of the insertion portion into the container comes into close contact with the liquid surface.

Description

[Technical Field]

[0001] The present invention relates to a dissolved oxygen consumption measuring device and a dissolved oxygen consumption measuring method that can predict the biochemical oxygen demand (BOD) of a sample. [Background technology]

[0002] Biochemical oxygen demand (BOD) is a commonly known water quality index. BOD represents the amount of organic matter in water as the amount of dissolved oxygen consumed by microorganisms in the water. Generally, the higher the BOD value, the worse the water quality is evaluated to be.

[0003] BOD values ​​vary depending on the type of sample, and if the analytical value of the diluted sample (the difference between the first and second dissolved oxygen concentration measurements) falls outside the specified concentration range, it becomes necessary to adjust the dilution and repeat the measurement again. As a result, not only does it take extra time to obtain BOD measurement results, but it also forces the use of samples that have been stored for a long time, which results in the problem of not being able to obtain the true BOD value.

[0004] A technique for obtaining BOD measurement results in a short period of time has been disclosed. The method and device for measuring biochemical oxygen demand disclosed in Patent Document 1 obtains the amount of dissolved oxygen consumed by aerobic microorganisms in a sample over a short period of time (for example, two hours), and predicts the BOD value of the sample based on the obtained amount of dissolved oxygen consumed.

[0005] Patent document 2 discloses a BOD measuring instrument and its control method that uses a microbial electrode and a flow cell in which the sample is placed in contact with the microbial electrode, thereby eliminating noise caused by air contamination, which can cause errors in BOD measurement.

[0006] Patent Document 3 discloses a dissolved oxygen consumption measuring device that includes a container, a sample liquid supply flow path for supplying sample liquid, an air supply flow path for supplying aeration air, a supply nozzle for supplying fluid selectively supplied from the sample liquid supply flow path and the air supply flow path into the container, and a dissolved oxygen sensor for detecting the dissolved oxygen concentration of the sample liquid supplied to the container, and shows that the BOD value can be predicted from the dissolved oxygen consumption rate measured by this device. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2000-046823 [Patent Document 2] Patent Publication No. 2000-121627 [Patent Document 3] Patent No. 7531877 Summary of the Invention [Problem to be solved by the invention]

[0008] In the device disclosed in Patent Document 3, aeration by air supply and dissolved oxygen measurement are performed by separate arms, so the configuration of this device makes it impossible to measure dissolved oxygen immediately after aeration. Therefore, the initial value for calculating the dissolved oxygen consumption rate is calculated based on a preset saturated oxygen concentration (see paragraph

[0072] of the same document). However, depending on the sample, the initial value can be a value that is far from the saturated oxygen amount, which can cause errors.

[0009] Furthermore, the device configuration disclosed in Patent Document 3 cannot eliminate the influence of oxygen in the air dissolving into the specimen from the time of supplying the aeration air until the time of measuring the dissolved oxygen, and is therefore insufficient to measure the dissolved oxygen consumption rates of multiple specimens using a single dissolved oxygen sensor.

[0010] That is, the problem to be solved by the present invention is to provide a dissolved oxygen consumption measuring device and a dissolved oxygen consumption measuring method that can predict the BOD value of a sample with high accuracy. [Means for solving the problem]

[0011] That is, the present invention provides a dissolved oxygen consumption measuring device comprising a container for holding a liquid, a dissolved oxygen sensor, a nozzle for supplying air, an arm that operates to insert the dissolved oxygen sensor and the nozzle into the container, and a lid that is attached to the container to make it airtight and has a portion that is inserted into the container, wherein operation of the arm causes the liquid in the container to overflow, and after operation of the arm, when the lid is attached, the liquid in the container further overflows, and the underside of the portion that is inserted into the container comes into close contact with the surface of the liquid.

[0012] Another present invention may be a dissolved oxygen consumption measuring device in which the dissolved oxygen sensor and the nozzle are inserted into the container to measure the amount of dissolved oxygen in the liquid after air is supplied by the nozzle, and the lid is attached after the dissolved oxygen sensor and the nozzle are pulled out from the container.

[0013] Another aspect of the present invention may be the dissolved oxygen consumption measuring device, wherein a displacement volume of the insertion portion of the lid into the container is equal to or greater than a displacement volume caused by the insertion movement of the arm.

[0014] In another aspect of the present invention, the dissolved oxygen amount in the liquid can be measured by inserting the dissolved oxygen sensor into the container using the arm after a predetermined time has elapsed since the lid was attached.

[0015] The arm may include a plate-like member that closes the opening of the container when the arm completes the insertion operation of the dissolved oxygen sensor.

[0016] Another aspect of the present invention may be a dissolved oxygen consumption measuring device comprising a plurality of the containers, a turntable that holds the containers in a ring shape, and a drainage channel that drains liquid that overflows from the containers radially outward from the turntable.

[0017] Another aspect of the present invention may be a dissolved oxygen consumption measuring device that includes a first lid that is attached to the container until the dissolved oxygen sensor and the nozzle are inserted into the container, and a second lid that is attached to the container after the dissolved oxygen sensor and the nozzle are removed, wherein the displacement volume of the container insertion portion of the first lid is smaller than the displacement volume due to movement of the arm, and the displacement volume of the container insertion portion of the second lid is equal to or larger than the displacement volume due to movement of the arm.

[0018] Yet another aspect of the present invention may be a dissolved oxygen consumption measuring device that includes a plurality of second lid mounting portions arranged in a ring on the turntable for mounting the second lids, and the second lid mounting portions are arranged in a radial direction connecting the corresponding containers and the center of the turntable.

[0019] The present invention provides a method for measuring dissolved oxygen consumption using a dissolved oxygen consumption measuring device comprising: a container for holding a liquid, a dissolved oxygen sensor, a nozzle for supplying air, an arm that operates to insert the dissolved oxygen sensor and the nozzle into the container, and a lid that is attached to the container to airtightly seal the container and has a container insertion portion, the method comprising the steps of: causing the liquid in the container to overflow by operating the arm; measuring the amount of dissolved oxygen in the liquid after air is supplied by the nozzle; attaching the lid to the container after measuring the amount of dissolved oxygen; and measuring the amount of dissolved oxygen in the liquid in the container after a predetermined time has elapsed; wherein, when the lid is attached, the liquid in the container overflows and the underside of the container insertion portion comes into close contact with the liquid surface. [Effects of the Invention]

[0020] The present invention allows for accurate measurement of the dissolved oxygen content (initial value) immediately after aeration by inserting the dissolved oxygen sensor and nozzle into the container. Furthermore, by overflowing the liquid twice from the container, the influence of the gas phase on the sample liquid during the waiting period is minimized, allowing for accurate measurement of the dissolved oxygen content (final value) after the waiting period. Therefore, the present invention allows for highly accurate prediction of the BOD value of a liquid. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a front view schematically showing the overall configuration of a dissolved oxygen consumption measuring device according to an embodiment of the present invention. [Figure 2] 1 is a plan view showing a schematic diagram of the overall configuration of a dissolved oxygen consumption measuring device according to the present embodiment. To simplify the drawing, only representative elements among the fitting hole 20, the liquid receiving portion 22, the drain pipe 24, and the second lid mounting portion 46 are labeled with reference numerals, and other elements are omitted. [Figure 3] 1 is a perspective view showing a schematic diagram of another configuration of the drainage channel of the turntable according to the present embodiment. Note that, for the sake of simplicity, only representative elements among the multiple fitting holes 20, the liquid receiving portion 22, and the drainage pipe 24 are labeled with reference numerals, and other elements are omitted. [Figure 4] 1 is a schematic diagram illustrating the operation of each step (from opening the first lid to attaching the second lid) of the method for measuring dissolved oxygen consumption of the present invention. [Figure 5] 2 is a schematic diagram showing the operation of each step of the method for measuring dissolved oxygen consumption of the present invention (from opening the second lid to measuring the final value). FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] The dissolved oxygen consumption measuring device of the present invention will be described in detail below based on embodiments of the invention, but the present invention should not be construed as being limited to the following embodiments.

[0023] A dissolved oxygen consumption measuring device 10 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view of the dissolved oxygen consumption measuring device 10, and FIG. 2 is a plan view of the dissolved oxygen consumption measuring device 10. The dissolved oxygen consumption measuring device 10 includes a plurality of containers 12. The containers 12 contain sample liquids. The dissolved oxygen consumption measuring device 10 of this embodiment includes 20 containers 12. These containers 12 are arranged at equal intervals in a circle and are held on a turntable 14.

[0024] 1, only two representative containers 12 arranged diagonally are shown, and the other containers are omitted, in order to simplify understanding of the configuration of the dissolved oxygen consumption measuring device 10. Also, in FIG. 2, the configuration is shown excluding the containers 12 and the second lid 18, in order to simplify understanding of the configuration other than the containers 12 and the second lid 18.

[0025] As shown in Figures 4 and 5, the container 12 in this embodiment has a substantially hemispherical bottom and a cylindrical body. The container 12 is also provided with a lid that closes an opening formed at the upper edge of the body. In this embodiment, two types of lids, a first lid 16 and a second lid 18, are used. The first lid 16 and the second lid 18 are attached to the container 12 so as to airtightly seal it, as will be described in detail below. The number of containers 12 in the dissolved oxygen consumption measuring device is not limited to the above and can be changed as appropriate.

[0026] The turntable 14 is formed in a disk shape and has fitting holes 20 into which a plurality of containers 12 are individually fitted and held. The containers 12 are fixed on the turntable 14 by being fitted vertically into the fitting holes 20. In this embodiment, there are 20 fitting holes 20; however, like the number of containers 12, the number of fitting holes 20 may be changed as appropriate. Note that in FIG. 1 , the containers 12 are arranged by being fitted into the fitting holes 20, and therefore the fitting holes 20 are hidden by the containers 12 and are difficult to illustrate. Therefore, for the specific arrangement of the fitting holes 20, please refer to FIGS. 2 and 3, in which the containers 12 are omitted.

[0027] A liquid receiving portion 22 that receives liquid that overflows from the container 12 is provided on the outer periphery of the fitting hole 20. The opening diameter of the liquid receiving portion 22 is larger than the diameter of the fitting hole 20, and the fitting hole 20 is contained within the liquid receiving portion 22. A drain pipe 24 is provided in the liquid receiving portion 22 to drain the received liquid radially outward from the turntable 14. The drain pipe 24 extends radially from the turntable 14 and is positioned so that it can transfer the liquid to a liquid discharge portion 26 when the turntable 14 reaches a specific rotational position. The liquid discharge portion 26 discharges the liquid transferred from the drain pipe 24 to the outside of the device.

[0028] 3, an annular drain channel 29 is provided around the outer periphery of the turntable 14 to receive the wastewater from each drain pipe 24. The annular drain channel 29 is inclined to guide the wastewater to one location, and the guided wastewater is discharged outside the device. In this embodiment, the wastewater can be drained from locations other than the specific rotational position.

[0029] Also provided on the turntable 14 are second lid placement portions 46 for placing second lids 18 to be attached to the containers 12. The second lid placement portions 46 are arranged in a ring shape, and the number of second lid placement portions 46 is the same as the number of containers 12 (and the fitting holes 20 into which the containers 12 fit). The second lid placement portion 46 corresponding to one container 12 is arranged in the radial direction connecting the center of the turntable 14 and that container 12, and as can be seen from FIG. 2, in this embodiment, the second lid placement portion 46 is arranged radially inward from the container 12 (and the fitting holes 20).

[0030] The arm support column 28 holds the sensor arm 30, the opening / closing arm 32, and a horizontal arm 33 that transports both arms horizontally. The sensor arm 30 and the opening / closing arm 32 can be raised and lowered independently in the vertical direction (up and down in FIG. 1). The horizontal arm 33 transports the sensor arm 30 and the opening / closing arm 32 horizontally (left and right in FIG. 1) and selectively moves each arm above a predetermined working position.

[0031] The sensor arm 30 holds a dissolved oxygen sensor 34, an agitator blade 36, and an air supply nozzle 38. The dissolved oxygen sensor 34 is a sensor for measuring the dissolved oxygen concentration of the sample liquid and is equipped with an electrode for measuring dissolved oxygen. The air supply nozzle 38 is connected to an electric air pump (not shown) via a tubular air supply path (not shown). When the electric air pump is driven, aeration air is discharged from the air supply nozzle 38.

[0032] The sensor arm 30 moves up and down vertically (up and down in FIG. 1) at a predetermined position, thereby inserting the dissolved oxygen sensor 34, stirring blade 36, and air supply nozzle 38 into the container 12 when the container 12 is at a specific rotational position on the turntable 14. After supplying aeration air and measuring the dissolved oxygen, the sensor arm 30 operates to withdraw the dissolved oxygen sensor 34, stirring blade 36, and air supply nozzle 38 from the container 12.

[0033] The sensor arm 30 is equipped with a splash guard 40, which is a plate-like member that protrudes horizontally. The splash guard 40 is positioned so that it comes into contact with the opening of the container 12 when the dissolved oxygen sensor 34, the stirring blade 36, and the air supply nozzle 38 are inserted to a predetermined depth into the container 12. Because the splash guard 40 closes the opening of the container 12, even when aeration air is supplied into the container 12, splashes of the sample liquid in the container 12 are prevented from scattering outside the container 12, and the sample liquid can be kept within the container 12.

[0034] The cleaning container 39 contains cleaning water for cleaning the dissolved oxygen sensor 34, the stirring blade 36, and the air supply nozzle 38. After the dissolved oxygen measurement of the sample liquid is completed, the sensor arm 30 moves horizontally above the cleaning container 39 by the operation of the horizontal arm 33, and then descends vertically at a predetermined position to insert the dissolved oxygen sensor 34, the stirring blade 36, and the air supply nozzle 38 into the cleaning container 39, thereby immersing them in the cleaning water. In this cleaning process, the stirring blade 36 stirs the cleaning water, thereby enhancing the cleaning effect. Note that pure water or distilled water is used as the cleaning water contained in the cleaning container 39.

[0035] The horizontal arm 33 moves the position of the opening / closing arm 32 in the horizontal direction (left and right direction in FIG. 1), and the opening / closing arm 32 moves up and down in the vertical direction (up and down direction in FIG. 1). The tip of the opening / closing arm 32 is provided with a suction part 42 that suction-holds the lid (first lid 16 and / or second lid 18).

[0036] The opening / closing arm 32 is transported by the horizontal arm 33 and performs the following operations: adsorbing the lid (first lid 16 and / or second lid 18) of the container 12 at a specific rotational position on the turntable 14 and opening the container 12; retracting the adsorbed lid (first lid 16 and / or second lid 18) by releasing the adsorption on the lid retraction section 44; adsorbing and holding the second lid on the second lid placement section 46; and attaching the adsorbed second lid to the container 12 at a specific rotational position to airtightly seal the container 12.

[0037] A magnetic stirrer 47 is provided below a specific rotation position of the turntable 14. In addition to the sample liquid, a stirring bar (not shown) is previously placed in the container 12. Before measuring the initial value of the dissolved oxygen amount, which will be described later, the stirring bar is rotated by the magnetic stirrer 47 for a certain period of time to stir the sample liquid until it becomes homogeneous.

[0038] 4 and 5, a method for measuring dissolved oxygen consumption using the dissolved oxygen consumption measuring device 10 will be described. The arrows in the figures indicate the direction of movement of the sensor arm 30 or the open / close arm 32 in each step. The container 12 containing the sample liquid has its opening closed by the first lid 16 and is held on the turntable 14 in an airtight state.

[0039] When the operation of the dissolved oxygen consumption measuring device 10 is started, the opening / closing arm 32 descends vertically toward the container 12 (FIG. 4(A)). When the suction part 42 is joined to the upper surface of the first lid 16, the suction part 42 adsorbs and holds the first lid 16. The opening / closing arm 32 then rises, removing the first lid 16 from the container 12 (FIG. 4(B)). Next, the opening / closing arm 32 is moved horizontally by the horizontal arm 33, and releases the suction from the first lid 16 on the lid retraction part 44, retracting the first lid 16 (this step is not shown).

[0040] Next, the sensor arm 30 descends vertically toward the container 12, and the dissolved oxygen sensor 34 and the air supply nozzle 38 are inserted together into the container 12 containing the sample liquid (FIG. 4(C)). At this point, a volume of sample liquid equivalent to the displacement volume caused by the insertion of the dissolved oxygen sensor 34 and the air supply nozzle 38 overflows from the container 12. That is, the container 12 is designed to previously contain a volume of sample liquid that will overflow when the dissolved oxygen sensor 34 and the air supply nozzle 38 are inserted. Furthermore, the displacement volume of the first cover container insertion portion 48 is smaller than the displacement volume caused by the operation of the sensor arm 30, i.e., the insertion of the dissolved oxygen sensor 34 and the air supply nozzle 38. The overflowing sample liquid is temporarily received in the liquid receiving portion 22 and then discharged through the drainage channel 24.

[0041] When the dissolved oxygen sensor 34 and air supply nozzle 38 reach a predetermined depth in the sample liquid, aeration air is supplied from the air supply nozzle 38 into the sample liquid for a certain period of time. At this time, a splash prevention plate 40 fits into the opening of the container at the insertion position of the sensor arm 30, preventing the sample liquid from dissipating during aeration. Immediately after the supply of aeration air is stopped, the dissolved oxygen sensor 34 measures the amount of dissolved oxygen (initial value) in the sample liquid, and the measurement value is recorded by a recording device (not shown).

[0042] Next, the sensor arm 30 rises, and the dissolved oxygen sensor 34 and the air supply nozzle 38 are pulled out of the container 12 (this step is not shown). Next, the opening / closing arm 32 is carried by the horizontal arm 33 to above the second lid mounting portion 46 and descends toward the second lid mounting portion 46 corresponding to the container 12, and the suction portion 42 suctions the upper surface of the second lid 18 (this step is not shown). Furthermore, the opening / closing arm 32 is carried by the horizontal arm 33 to above the container 12 and descends toward the container 12 (FIG. 4(D)). The opening / closing arm 32 descends, and the second lid 18 is attached to the container 12, making the container 12 airtight (FIG. 4(E)).

[0043] Here, the second lid 18 has a second lid container insertion part 50 that is inserted into the container, and the displacement volume of the second lid container insertion part 50 is set to be larger than the displacement volume due to the insertion of the dissolved oxygen sensor 34 and the air supply nozzle 38. Therefore, when the second lid 18 is closed, a volume of sample liquid equivalent to the difference in displacement volume overflows from the container 12. The overflowing sample liquid is temporarily received in the liquid receiving part 22 and then discharged through the drainage channel 24.

[0044] As a result of the overflow of the sample liquid due to the closing of the second lid 18, the second lid container insertion portion 50 comes into close contact with the liquid surface of the sample liquid. In other words, this overflow removes air above the sample liquid from the container 12, minimizing the gas phase within the container 12. The container 12 is left standing for a predetermined time in an airtight state with the second lid 18. After the predetermined time has elapsed, the opening / closing arm 32 descends vertically (FIG. 5(H)), and then rises with the suction portion 42 still suction-holding the second lid 18, thereby removing the second lid 18 from the container 12 (FIG. 5(I)).

[0045] Next, the sensor arm 30 descends again, inserting the dissolved oxygen sensor 34 into the container 12. When the dissolved oxygen sensor 34 reaches a predetermined depth in the sample liquid, it measures the amount of dissolved oxygen in the sample liquid (final value). The amount of dissolved oxygen consumed by the sample liquid is calculated from the difference between the initial value and the final value. The calculated amount of dissolved oxygen consumed minimizes the influence of the gas phase in the container 12, allowing an accurate understanding of the amount of dissolved oxygen consumed by the sample liquid.

[0046] While the container 12 is left stationary for a predetermined time in an airtight state with the second lid 18, the turntable 14 rotates, and the container to be measured next moves to the lowered position of the open / close arm 32 and the sensor arm 30. After the container 12 is moved, the open / close arm 32, the sensor arm 30, etc. perform the above-mentioned process, i.e., the process illustrated in Figures 4(A) to (E). In this way, the predetermined time spent waiting for the dissolved oxygen consumption of the sample liquid in one container can be used to measure the initial value of the next sample liquid. In this way, continuous processing of multiple specimens is performed.

[0047] The dissolved oxygen consumption measuring device 10 includes a control device 52. The control device 52 includes, for example, a computer in which an OS (operating system) and a predetermined application program are installed, and the computer includes a user interface such as a touch panel 54 and a storage device (not shown) such as a memory or a hard disk.

[0048] The control device 52 comprehensively controls the operations of the turntable 14, sensor arm 30, open / close arm 32, horizontal arm 33, etc., based on various input information (including sensor information that detects the position of each operating member) and a predetermined procedure (application program). These operational controls execute the above-described dissolved oxygen consumption measurement method. [Explanation of symbols]

[0049] 10. Dissolved oxygen consumption measuring device 12 containers 14 Turntable 16 1st lid 18 Second lid 20 mating holes 22 Liquid receiving section 24 Drain pipe 26 Liquid drain 28 Arm support column 29 Circular Drainage Channel 30 Sensor arm 32 Opening and closing arm 33 Horizontal arm 34 Dissolved oxygen sensor 36 Mixing blade 38 Air supply nozzle 39 Cleaning container 40 Splash prevention plate 42 Adsorption part 44 Lid retraction section 46 2nd lid placement part 47 Magnetic Stirrer 48 First lid container insertion part 50 Second lid container insertion part 52 Control device 54 Touch Panel

Claims

1. a container for containing a liquid; a dissolved oxygen sensor; a nozzle for supplying air; an arm operable to insert the dissolved oxygen sensor and the nozzle into a container; a lid attached to the container so as to seal the container, the lid having an insertion portion into the container; The movement of the arm causes the liquid in the container to overflow, After the arm is moved, when the lid is attached, the liquid in the container further overflows, and the lower surface of the container insertion portion comes into close contact with the liquid surface. Dissolved oxygen consumption measuring device.

2. The dissolved oxygen sensor and the nozzle are inserted into the container to measure the amount of dissolved oxygen in the liquid after air is supplied by the nozzle; The lid is attached after the dissolved oxygen sensor and the nozzle are removed from the container. The dissolved oxygen consumption measuring device according to claim 1 .

3. The displacement volume of the insertion portion of the lid into the container is equal to or greater than the displacement volume caused by the insertion movement of the arm. The dissolved oxygen consumption measuring device according to claim 2 .

4. When a predetermined time has elapsed since the lid was attached, the dissolved oxygen sensor is inserted into the container by the arm, thereby measuring the amount of dissolved oxygen in the liquid. The dissolved oxygen consumption measuring device according to claim 2 .

5. the arm includes a plate-like member that closes the opening of the container when the arm completes the insertion operation of the dissolved oxygen sensor. The dissolved oxygen measuring device according to claim 1 .

6. A plurality of said containers; a turntable that holds the container in a circular shape; a drainage channel for draining liquid overflowing from the container to the radially outer side of the turntable, The dissolved oxygen consumption measuring device according to claim 1 .

7. a first lid that is attached to the container until the dissolved oxygen sensor and the nozzle are inserted into the container; a second lid that is attached to the container after the dissolved oxygen sensor and the nozzle are removed, a displacement volume of the container insertion portion of the first lid is smaller than a displacement volume caused by the movement of the arm; The displacement volume of the container insertion portion of the second lid is equal to or greater than the displacement volume caused by the movement of the arm. The dissolved oxygen consumption measuring device according to any one of claims 1 to 6.

8. A first lid attached to the container until the dissolved oxygen sensor and the nozzle are inserted into the container; a second lid that is attached to the container after the dissolved oxygen sensor and the nozzle are removed, a plurality of second lid placement portions on which the second lids are placed are provided in an annular arrangement on the turntable; The second lid placement portion is disposed in a radial direction connecting the corresponding container and the center of the turntable. The dissolved oxygen consumption measuring device according to claim 6.

9. a container for containing a liquid; a dissolved oxygen sensor; a nozzle for supplying air; an arm operable to insert the dissolved oxygen sensor and the nozzle into a container; a lid attached to the container so as to airtightly seal the container and having a container insertion portion; The movement of the arm causes the liquid in the container to overflow; measuring the amount of dissolved oxygen in the liquid after air is supplied through the nozzle; attaching the lid to the container after measuring the amount of dissolved oxygen; and measuring the amount of dissolved oxygen in the liquid in the container after a predetermined time has elapsed; When the lid is attached, the liquid in the container overflows and the lower surface of the container insertion portion comes into close contact with the liquid surface. Dissolved oxygen consumption measurement method.

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