JP2012172978A - Trihalomethane measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress variance in measured concentration of trihalomethane with the passage of time.SOLUTION: A trihalomethane measuring apparatus includes a reagent tank 22a which stores a sodium hydroxide solution, piping 22b which opens the inside of the reagent tank 22a into the atmosphere, and an adsorption device 22c which is provided in the piping 22b for removing carbon dioxide contained in the atmosphere introduced into the reagent tank 22a. Thus, carbon dioxide contained in the atmosphere introduced into the reagent tank 22a is removed, thereby suppressing variance in measured concentration of trihalomethane with the passage of time.

Description

  The present invention relates to a trihalomethane measuring apparatus for measuring the concentration of trihalomethane contained in water.

  Chloroform, bromodichloromethane, dibromochloromethane, and bromoform (hereinafter collectively referred to as trihalomethane) react with organic substances such as humic substances contained in tap water and disinfecting chlorine used in the water purification process of tap water. Is generated by This trihalomethane is known to be a carcinogen. For this reason, in the water purification plant, the concentration of trihalomethane contained in the water is managed as one of the water quality standard items.

  From such a background, the patent applicant has proposed the trihalomethane measuring apparatus described in Patent Document 1 so far. This trihalomethane measuring device dissolves and transfers the trihalomethane in the sample solution containing the sample water containing trihalomethane and the acidic reducing agent solution in the carrier solution in which the fluorescence analysis reagent and the sodium hydroxide solution are mixed. The concentration of trihalomethane is measured by generating a fluorescent substance from the trihalomethane and the fluorescence analysis reagent in the carrier liquid and measuring the fluorescence intensity of the carrier liquid containing the fluorescent substance.

JP 2009-14382 A

  The inventors of the present invention have found that according to the trihalomethane measuring apparatus described in Patent Document 1, the measured concentration of trihalomethane varies with the passage of time, even though the actual concentration of trihalomethane does not vary. did. For this reason, provision of the technique which can suppress the fluctuation | variation of the measurement density | concentration of trihalomethane with time passage was anticipated.

  This invention is made | formed in view of the said subject, The objective is to provide the trihalomethane measuring apparatus which can suppress the fluctuation | variation of the measurement density | concentration of the trihalomethane with time passage.

  As a result of intensive studies, the inventors of the present invention have found that the variation in the measured concentration of trihalomethane over time is that the atmosphere enters the reagent tank that stores the sodium hydroxide solution with the consumption of sodium hydroxide, It has been found that the sodium hydroxide solution absorbs carbon dioxide contained in the atmosphere, thereby causing the pH value of the sodium hydroxide solution to decrease.

  The trihalomethane device according to the present invention, which has been conceived based on the above knowledge, comprises a sample liquid feeding section for feeding a sample solution in which a sample water containing trihalomethane and an acidic reducing agent solution are mixed, a fluorescence analysis reagent, and a sodium hydroxide solution. A carrier liquid feeding part for feeding the mixed carrier liquid, a separation and dissolving part for feeding and transferring the trihalomethane in the sample solution into the carrier liquid, the sample solution and the carrier liquid being supplied, and the trihalomethane dissolving and transferring The carrier liquid is supplied, a reaction unit that generates a fluorescent substance from the trihalomethane and the fluorescence analysis reagent in the carrier liquid, a carrier liquid containing the fluorescent substance is supplied, and the fluorescence intensity of the fluorescent substance in the carrier liquid is increased. A trihalomethane measuring device comprising a detector for quantifying trihalomethane by measuring, A reagent tank for storing a thorium solution, an air introduction path for opening the inside of the reagent tank to the atmosphere, and carbon dioxide provided in the air introduction path for removing carbon dioxide contained in the atmosphere introduced into the reagent tank Removing means.

  According to the trihalomethane measuring apparatus according to the present invention, since carbon dioxide contained in the atmosphere introduced into the reagent tank is removed, fluctuations in the measured concentration of trihalomethane over time can be suppressed.

FIG. 1 is a schematic diagram showing an overall configuration of a trihalomethane measuring apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a configuration of an adsorption device according to an embodiment of the present invention. FIG. 3 is a diagram showing a change in measured concentration of trihalomethane with the elapsed days when carbon dioxide in the atmosphere is removed by the adsorption device and when it is not removed.

  Hereinafter, a configuration of a trihalomethane measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings.

〔overall structure〕
First, the overall configuration of a trihalomethane measuring apparatus according to an embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is a schematic diagram showing a configuration of a trihalomethane measuring apparatus according to an embodiment of the present invention. As shown in FIG. 1, a trihalomethane measuring apparatus according to an embodiment of the present invention includes a sample feeding unit 10 that sends out a sample solution in which sample water containing trihalomethane and an acidic reducing agent solution are mixed, and a fluorescence analysis reagent for trihalomethane. (Hereinafter abbreviated as "fluorescence analysis reagent") and a carrier solution mixture 20 for sending out a carrier solution mixed with sodium hydroxide solution, a separation and dissolution unit 30 for dissolving and transferring trihalomethane in the sample solution into the carrier solution, and trihalomethane A reaction unit 40 that generates a fluorescent substance from the trihalomethane and the fluorescence analysis reagent in the carrier solution into which the carrier has been dissolved and transferred, and a detection unit 50 that quantifies trihalomethane by measuring the fluorescence intensity of the carrier liquid containing the fluorescent substance. I have.

  The sample solution supply unit 10 includes a sample solution main tube 14 for supplying the sample solution to the sample solution flow path 33 of the separation and dissolution unit 30 and two branch pipes connected to the sample solution main tube 14, that is, trihalomethane. A branch pipe 11 for sample water and a branch pipe 12 for an acidic reducing agent solution are disposed. The two branch pipes 11 and 12 are provided with a liquid feed pump 13 for sending liquid to the main pipe 14 side, and open / close solenoid valves 15a and 15b. In addition, as an acidic reducing agent solution, the hydrazine sulfate solution can be illustrated, The density | concentration should just be about 1 [%], for example.

  The carrier liquid feeding unit 20 is provided with a branch pipe 21 for a fluorescence analysis reagent, a branch pipe 22 for a sodium hydroxide solution, and a sealed mixing tank 23 to which the branch pipes 21 and 22 are connected. A reagent tank 22 a for storing a sodium hydroxide solution is connected to the branch pipe 22, and the sodium hydroxide solution in the reagent tank 22 a is supplied into the mixing tank 23 through the branch pipe 22. As will be described in detail later, the reagent tank 22a includes a pipe 22b for releasing the inside of the reagent tank 22a to the atmosphere, and an adsorption device 22c for adsorbing and removing carbon dioxide contained in the atmosphere supplied to the reagent tank 22a. And are provided. The pipe 22b and the adsorption device 22c function as an air introduction path and a carbon dioxide removal unit according to the present invention, respectively.

  The mixing tank 23 is provided with a pipe 24 in which an air pump 25 for making the inside of the mixing tank 23 negative and a pressure gauge 16 for measuring the pressure in the mixing tank 23 are installed. A carrier liquid main pipe 26 is disposed between the lower portion of the side surface of the mixing tank 23 and the carrier liquid flow path 34 of the separation and dissolution section 30.

  The carrier liquid main pipe 26 is provided with a liquid feed pump 29 for sending a carrier liquid obtained by mixing a fluorescence analysis reagent and a sodium hydroxide solution to the separation and dissolution unit 30 side. In addition, as a reagent for fluorescence analysis, a nicotinamide solution can be illustrated, and it is preferable that the density | concentration exists in the range of 30-40 [%]. The concentration of the sodium hydroxide solution is preferably in the range of 0.2 to 0.4 [M].

  The mixing tank 23 is provided with a pipe 27 for opening the inside of the mixing tank 23 to the atmosphere, and an air blowing pipe 28 configured to blow out air from the bottom of the mixing tank 23. The pipes 27 and 28 and the branch pipes 21 and 22 are provided with open / close electromagnetic valves 15c to 15f, respectively.

  The separation and dissolution part 30 has a cylindrical shape, and a gas permeable tube 32 parallel to the axial direction is provided inside thereof. A gas-permeable flat membrane 31 is provided between the inner wall in the separation / dissolving portion 30 and the gas-permeable tube 32 in parallel therewith. A closed space is constituted by the inner wall of the separation and dissolution part 30 and the gas permeable flat membrane 31, and this closed space becomes the sample solution flow path 33. The inner space of the gas permeable tube 32 becomes the carrier liquid flow path 34, and the remaining space, that is, the space between the gas permeable tube 32 and the gas permeable flat membrane 31 and the inner wall of the separation / dissolution part 30 is air. It becomes a phase space.

  The separation and dissolution unit 30 is provided with a heater 35 for heating the sample solution to a temperature at which trihalomethane in the sample solution flowing through the sample solution channel 33 volatilizes. The gas phase space of the separation and dissolution unit 30 is provided with a cleaning air pipe 36 for supplying cleaning air into the gas phase space and an exhaust pipe 38 for discharging the cleaned air. Yes. The cleaning air pipe 36 is provided with an air pump 37 for sending cleaning air and an opening / closing electromagnetic valve 15g. The sample solution flow path 33 of the separation and dissolution unit 30 is provided with a drainage pipe 39 for discharging the sample solution from which trihalomethane has been separated and removed.

  Between the carrier liquid flow path 34 and the reaction part 40 of the separation and dissolution unit 30, a carrier liquid pipe 41 that connects them is disposed. The reaction unit 40 heats the carrier liquid to a temperature at which the trihalomethane in the carrier liquid reacts with the fluorescence analysis reagent to generate a fluorescent substance by heating the carrier liquid piping 41 using, for example, boiling water. A device (not shown) is provided.

  Between the reaction part 40 and the detection part 50, the piping 51 for carrier liquid which connects these is arrange | positioned. The detection unit 50 is provided with a device (not shown) that measures the fluorescence intensity of the fluorescent substance in the carrier liquid and calculates the concentration of trihalomethane in the sample water from the measured value and a preset calibration curve. Yes. The detection unit 50 is provided with a pipe 52 for discharging the carrier liquid after measurement. This pipe 52 joins the drainage pipe 39 of the separation and dissolution unit 30 and then goes to a waste liquid treatment facility (not shown). It is connected.

[Configuration of adsorption device]
Next, the configuration of the adsorption device 22c will be described with reference to FIG.

  FIG. 2 is a schematic diagram showing the configuration of the adsorption device 22c according to one embodiment of the present invention. As shown in FIG. 2, the adsorption device 22c according to an embodiment of the present invention includes a storage container 22c2 that stores soda lime (soda lime) 22c1 having a characteristic of adsorbing carbon dioxide inside, and a storage container 22c2. An air passage 22c3 that is formed and communicates with the pipe 22b is provided. According to the adsorption device 22c having such a configuration, the air is supplied into the reagent tank 22a through the air passage 22c3. For this reason, carbon dioxide contained in the atmosphere is adsorbed by the soda lime 22c1 in the process of passing through the ventilation path 22c3, and carbon dioxide contained in the atmosphere supplied into the reagent tank 22a is removed. In order to increase the contact area and contact time between the atmosphere and soda lime 22c1, it is desirable that the air passage 22c3 be formed by bending the inside of the storage container 22c2.

[Experimental example]
Next, with reference to FIG. 3, the change of the measured concentration of trihalomethane with the elapsed days in the case where carbon dioxide in the atmosphere is removed by the adsorption device 22c and in the case where it is not removed will be described.

  FIG. 3 is a diagram showing a change in the measured concentration of trihalomethane with the elapsed days when the carbon dioxide in the atmosphere is removed by the adsorption device 22c and when it is not removed. As shown in FIG. 3, when the adsorption device 22c was not provided, the measured concentration of trihalomethane (THM measured value) fluctuated greatly when the number of elapsed days was 15 days or more. On the other hand, when the adsorption device 22c was provided, the measured concentration of trihalomethane did not vary greatly even when the number of days elapsed was 15 days or more. From the above, it has been found that by removing carbon dioxide contained in the atmosphere supplied into the reagent tank 22a, variation in the measured concentration of trihalomethane over time can be suppressed.

  The embodiment to which the invention made by the present inventors is applied has been described above, but the present invention is not limited by the description and the drawings that constitute a part of the disclosure of the present invention. That is, other embodiments, examples, operational techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Sample liquid feeding part 20 Carrier liquid feeding part 22 Branch pipe 22a Reagent tank 22b Piping 22c Adsorption device 22c1 Soda lime 22c2 Container 22c3 Air passage 30 Separation / dissolution part 40 Reaction part 50 Detection part

Claims (2)

A sample feeding part for sending out a sample solution in which a sample water containing trihalomethane and an acidic reducing agent solution are mixed; a carrier liquid feeding part for sending out a carrier liquid in which a fluorescent analysis reagent and a sodium hydroxide solution are mixed; and the sample solution And the carrier liquid are supplied, a separation and dissolution part for dissolving and transferring the trihalomethane in the sample solution into the carrier liquid, and a carrier liquid in which the trihalomethane is dissolved and transferred are supplied, and the trihalomethane and fluorescence analysis in the carrier liquid are supplied. A trihalomethane measurement comprising: a reaction unit that generates a fluorescent substance from a reagent; and a detection unit that is supplied with a carrier liquid containing the fluorescent substance and that quantifies trihalomethane by measuring the fluorescence intensity of the fluorescent substance in the carrier liquid. A device,
A reagent tank for storing the sodium hydroxide solution;
An air introduction path for opening the inside of the reagent tank to the atmosphere;
Carbon dioxide removing means for removing carbon dioxide contained in the atmosphere provided in the atmosphere introduction path and introduced into the reagent tank;
A trihalomethane measuring device comprising:   2. The trihalomethane measuring apparatus according to claim 1, wherein the carbon dioxide removing means includes soda lime that adsorbs carbon dioxide contained in the atmosphere introduced into the reagent tank.

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