A method and device for monitoring dissolved greenhouse gases in sewage

Abstract

The present invention discloses a monitoring method and device for dissolved greenhouse gases in sewage, comprising the following steps: S1, collecting sewage, and performing mud and water separation, collecting the supernatant of mud and water separation; S2, adding dilute sulfuric acid solution to the supernatant collected by using a headspace bottle to adjust the pH of the supernatant to 1-4, and tightening the bottle cap; S3, inverting the headspace bottle to check whether there are bubbles in the headspace bottle; S4, injecting 5-10mL pure nitrogen into the headspace bottle with a syringe, and discharging 5-10mL of sewage in the bottle through a catheter; S5, placing the headspace bottle in a water bath constant temperature shock box, shaking for 20-30 minutes; S6, extracting the gas on the top of the headspace bottle in S7, and measuring the concentration of the gas; S7, quantitatively calculating the concentration of dissolved greenhouse gases in the sewage of S1. The present invention can obtain the generation and release mechanism of greenhouse gases in the sewage treatment process, which is convenient for controlling and treating the greenhouse gases generated in the sewage treatment process.

Description

Technical Field

[0001] The present invention relates to the technical field of greenhouse gas monitoring, and in particular to a method and device for monitoring dissolved greenhouse gases in sewage. Background Art

[0002] Extreme climate changes such as global warming, rainfall, and high temperatures caused by excessive greenhouse gas emissions are threatening human survival. Greenhouse gas emissions from sewage treatment plants have become a key focus of environmental monitoring systems. Greenhouse gases including CH4 and N2O are intermediate products that are continuously produced and consumed during the biochemical reaction of sewage treatment. They are affected by sewage treatment process operating parameters (such as DO, aeration intensity, SRT, etc.), changes in influent water quality conditions (such as influent NH4 + , COD, etc.) and environmental factors (temperature, extreme weather, etc.) have different degrees of influence. Dissolved greenhouse gases are the transition state from the generation to the release of greenhouse gases. It is also one of the indicators to judge whether the biochemical reaction in the sewage treatment process is in the best reaction conditions. It is of great significance to the greenhouse gas emission reduction research of sewage treatment plants. A reasonable method is needed to monitor dissolved greenhouse gases in sewage. Summary of the invention

[0003] The purpose of the present invention is to provide a method and device for monitoring dissolved greenhouse gases in sewage to solve the problems existing in the prior art.

[0004] To achieve the above object, the present invention provides the following solution: The present invention provides a method for monitoring dissolved greenhouse gases in sewage, comprising the following steps:

[0005] S1, using a sewage collection device to collect sewage, and perform mud-water separation, and using a headspace bottle to collect the supernatant of the mud-water separation;

[0006] S2, adding a dilute sulfuric acid solution to the supernatant collected by the headspace bottle to adjust the pH of the supernatant to 1-4, and then tightening the bottle cap;

[0007] S3, invert the headspace bottle and check whether there are bubbles in the headspace bottle. If there are bubbles, discard the water sample and repeat steps S1-S2 to resample; if there are no bubbles, place the headspace bottle in a refrigerator for storage;

[0008] S4, inject 5-10 mL of pure nitrogen into the headspace bottle with a syringe, and discharge 5-10 mL of sewage in the bottle through the catheter;

[0009] S5, placing the headspace bottle in a water bath constant temperature shaking box, shaking for 20-30 minutes, so that the gas-liquid two phases in the headspace bottle reach headspace equilibrium;

[0010] S6, extracting the gas from the headspace bottle in S7, and measuring the concentration of the gas using gas chromatography;

[0011] S7, based on Henry's law and the gaseous greenhouse gas concentrations measured in S6, quantitatively calculate the dissolved greenhouse gas concentrations in the S1 wastewater.

[0012] According to the method for monitoring dissolved greenhouse gases in sewage provided by the present invention, in S2, the mass fraction of the dilute sulfuric acid solution is 20%.

[0013] According to the method for monitoring dissolved greenhouse gases in sewage provided by the present invention, in S3, the refrigeration temperature of the refrigerator is 0°C-4°C.

[0014] According to the method for monitoring dissolved greenhouse gases in sewage provided by the present invention, in S5, the headspace bottle is placed in a water bath constant temperature shaking box and shaken at 25° C. and 150-200 rpm for 20-30 minutes.

[0015] According to the method for monitoring dissolved greenhouse gases in sewage provided by the present invention, in S7, the dissolved greenhouse gases mainly include N2O and CH4.

[0016] According to the method for monitoring dissolved greenhouse gases in sewage provided by the present invention, the N2O concentration calculation equation is:

[0017]

[0018]

[0019] Where, C0 is the N2O concentration in the water sample (μmol·L-1), C g is the N2O concentration in the gas phase after headspace equilibrium (ppm, μmol / mol), C l is the N2O concentration in the liquid phase after headspace equilibrium (μmol·L-1), P and R are atmospheric pressure (101.325 kPa) and gas constant (8.314), respectively; T is absolute temperature (K), V g and V l are the volumes of the gas phase and liquid phase in the headspace bottle (mL), respectively. A1, A2, A3, A4 are constants of -165.8806, 222.8743, 92.0792 and -1.48425, respectively.

[0020] According to the monitoring method of dissolved greenhouse gases in sewage provided by the present invention, the dissolved CH4 concentration calculation equation is:

[0021]

[0022] Where, C0 is the CH4 concentration in the water sample (μmol·L-1), C gis the CH4 concentration in the gas phase after headspace equilibrium (μmol·L-1), β is the CH4 solubility coefficient (0.03096L·L-1·atm-1), R is the gas state constant (0.08206L·atm·mol-1·K-1), T is the absolute temperature (K), V m is the molar volume of CH4 under standard conditions (22.356 L·mol-1), V g and V l are the volumes of the gas phase and liquid phase in the headspace balancer (mL), respectively.

[0023] A monitoring device for dissolved greenhouse gases in sewage, characterized by comprising:

[0024] An open container, wherein two bottom plates are symmetrically slidably arranged at the bottom of the open container, and a slide seat is fixedly connected to the top surface of the two bottom plates respectively, and the slide seat is arranged at one end of the two bottom plates close to each other, and a slide rod is horizontally slidably connected to the slide seat, and one end of the slide rod is fixedly connected to the inner wall of the open container, and a spring is fixedly connected between the slide seat and the inner wall of the open container, and the spring is sleeved on the slide rod;

[0025] A long rod, the long rod is vertically arranged in the open container, the bottom end of the long rod is hinged with two hinged rods, the two hinged rods are respectively hinged with the sliding seats on the top surfaces of the two bottom plates, the upper limit position of the long rod is slidably connected with a filter screen, the filter screen is slidably matched with the inner wall of the open container; the outer wall of the long rod is threadedly connected with a threaded sleeve, and the threaded sleeve is rotatably connected to the top of the filter screen;

[0026] A connecting pipe is horizontally fixedly connected to the side wall of the open container, and a valve is arranged on the connecting pipe.

[0027] According to the monitoring device for dissolved greenhouse gases in sewage provided by the present invention, scale lines are arranged on the long rod.

[0028] According to the monitoring device for dissolved greenhouse gases in sewage provided by the present invention, an identification ring is sleeved on the long rod.

[0029] The present invention discloses the following technical effects:

[0030] The present invention fills the gap in dissolved greenhouse gas monitoring methods. Through the collection and quantification method of dissolved CH4 and N2O in the sewage treatment system of the present invention, the generation and release mechanism of greenhouse gases in the sewage treatment process can be understood, which is convenient for controlling and treating the greenhouse gases generated in the sewage treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 It is a schematic diagram of the structure of the monitoring device for dissolved greenhouse gases in sewage of the present invention;

[0033] Among them, 1. long rod; 2. filter screen; 3. open container; 4. valve; 5. connecting pipe; 6. bottom plate; 7. sliding seat; 8. sliding rod; 9. spring; 10. identification ring. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] The present invention provides a method for monitoring dissolved greenhouse gases in sewage, comprising the following steps:

[0037] S1, using a sewage collection device to collect sewage, and perform mud-water separation, and using a headspace bottle to collect the supernatant of the mud-water separation;

[0038] S2, adding dilute sulfuric acid solution to the supernatant collected by the headspace bottle to adjust the pH of the sewage to 1-4, and then tightening the bottle cap; the dilute sulfuric acid solution is used to inhibit the activity of nitrifying and denitrifying microorganisms;

[0039] S3, invert the headspace bottle and check whether there are bubbles in the headspace bottle. If there are bubbles, discard the water sample and repeat steps S1-S2 to resample; if there are no bubbles, place the headspace bottle in a refrigerator for storage;

[0040] S4, use a syringe to inject 5-10mL of pure nitrogen into the headspace bottle, and discharge 5-10mL of sewage in the bottle through the catheter; the volume of the headspace bottle is 20mL, use a 10mL syringe (with a 1.2*30 needle) to inject 10mL of pure nitrogen into the S5 headspace bottle,

[0041] S5, placing the headspace bottle in a water bath constant temperature shaking box, shaking for 20-30 minutes, so that the gas-liquid two phases in the headspace bottle reach headspace equilibrium;

[0042] S6, extracting the gas from the headspace bottle in S7, and measuring the concentration of the gas using gas chromatography;

[0043] S7, based on Henry's law and the gaseous greenhouse gas concentrations measured in S6, quantitatively calculate the dissolved greenhouse gas concentrations in the S1 wastewater.

[0044] The scheme is further optimized, in S2, the mass fraction of the dilute sulfuric acid solution is 20%.

[0045] Further optimizing the solution, in S3, the refrigerator refrigeration temperature is 0℃-4℃.

[0046] To further optimize the scheme, in S5, the headspace bottle was placed in a water bath constant temperature shaking box and shaken at 25°C and 150-200r for 20-30 minutes.

[0047] In the further optimized scheme, in S7, dissolved greenhouse gases mainly include N2O and CH4.

[0048] Further optimization scheme, the N2O concentration calculation equation is:

[0049]

[0050]

[0051] Where, C0 is the N2O concentration in the water sample (μmol·L-1), C g is the N2O concentration in the gas phase after headspace equilibrium (ppm, μmol / mol), C l is the N2O concentration in the liquid phase after headspace equilibrium (μmol·L-1), P and R are atmospheric pressure (101.325 kPa) and gas constant (8.314), respectively; T is absolute temperature (K), V g and V l are the volumes of the gas phase and liquid phase in the headspace bottle (mL), respectively. A1, A2, A3, A4 are constants of -165.8806, 222.8743, 92.0792 and -1.48425, respectively.

[0052] Further optimization scheme, dissolved CH4 concentration calculation equation is:

[0053]

[0054] Where, C0 is the CH4 concentration in the water sample (μmol·L-1), C gis the CH4 concentration in the gas phase after headspace equilibrium (μmol·L-1), β is the CH4 solubility coefficient (0.03096L·L-1·atm-1), R is the gas state constant (0.08206L·atm·mol-1·K-1), T is the absolute temperature (K), V m is the molar volume of CH4 under standard conditions (22.356 L·mol-1), V g and V l are the volumes of the gas phase and liquid phase in the headspace balancer (mL), respectively.

[0055] refer to Figure 1 The present invention also discloses a monitoring device for dissolved greenhouse gases in sewage, comprising:

[0056] An open container 3, the bottom of the open container 3 is horizontally and symmetrically slidably provided with two bottom plates 6, the top surfaces of the two bottom plates 6 are respectively fixedly connected with slide seats 7, the slide seats 7 are arranged at one end of the two bottom plates 6 close to each other, a slide rod 8 is horizontally slidably connected to the slide seat 7, one end of the slide rod 8 is fixedly connected to the inner wall of the open container 3, a spring 9 is fixedly connected between the slide seat 7 and the inner wall of the open container 3, and the spring 9 is sleeved on the slide rod 8; it needs to be considered that in actual use, the bottom plate 6 will be deflected during the sliding process, so it is necessary to open a slide groove at the bottom of the open container 3, and limit the bottom plate 6 by the slide groove, so as to ensure stable sliding between it and the open container 3.

[0057] A long rod 1 is vertically arranged in an open container 3. Two hinged rods are hinged at the bottom end of the long rod 1. The two hinged rods are respectively hinged to the slide seats 7 on the top surfaces of the two bottom plates 6. The upper limit position of the long rod 1 is slidably connected to a filter screen 2. The filter screen and the inner wall of the open container 3 are slidably matched. A threaded sleeve is threadedly connected to the outer wall of the long rod 1. The threaded sleeve is rotatably connected to the top of the filter screen 2.

[0058] A connecting pipe 5 is horizontally fixedly connected to the side wall of the open container 3 , and a valve 4 is provided on the connecting pipe 5 .

[0059] The open container 3 is provided with a portable handle. When in use, the portable long pole 1 is used to push the device deep into the sewage treatment pool so that the sewage fills the open container 3. The long pole 1 is provided with a width, and the rigidity of the water sample is preset by the identification ring 10, so as to facilitate the clear judgment of the depth of sewage collection. When the sewage in the open container 3 reaches the preset water level, the device is taken out of the sewage pool, and the threaded sleeve is rotated to push the filter screen 2 to move to a position below the water outlet 5 to achieve rapid mud and water separation. Then the valve 4 is opened, and the headspace bottle is used to collect sewage from the water outlet 5. After the supernatant is collected, close the valve 4, hold the portable handle with one hand, and push the long rod 1 with the other hand, so that the slide seat 7 slides relative to the slide rod 8, thereby pushing the bottom plate 6 to separate, and the mud and water at the bottom of the open container 3 are discharged from the device, so as to facilitate subsequent collection, and the filter screen 2 can continue to move downward to the bottom of the open container 3 to scrape off the sludge that may be attached to the side of the open container 3; after completing the above operations, reset the long rod 1 and the filter screen 2, and at the same time, a sealing member needs to be set on the bottom plate 6 to ensure the sealing effect of the device.

[0060] To further optimize the solution, scale lines are set on the long rod 1. The setting of the scale lines can control the depth of sewage collection.

[0061] According to a further optimized solution, a marking ring 10 is sleeved on the long rod 1 .

[0062] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0063] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For ordinary technical users in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for monitoring dissolved greenhouse gases in sewage, characterized in that: The steps include: S1, using a sewage collection device to collect sewage, and perform mud-water separation, and using a headspace bottle to collect the supernatant of the mud-water separation; S2, adding a dilute sulfuric acid solution to the supernatant collected by the headspace bottle to adjust the pH of the supernatant to 1-4, and then tightening the bottle cap; S3, invert the headspace bottle and check whether there are bubbles in the headspace bottle. If there are bubbles, discard the water sample and repeat steps S1-S2 to resample; if there are no bubbles, place the headspace bottle in a refrigerator for storage; S4, inject 5-10 mL of pure nitrogen into the headspace bottle with a syringe, and discharge 5-10 mL of sewage in the bottle through the catheter; S5, placing the headspace bottle in a water bath constant temperature shaking box, shaking for 20-30 minutes, so that the gas-liquid two phases in the headspace bottle reach headspace equilibrium; S6, extracting the gas from the headspace bottle in S5, and measuring the concentration of the gas using gas chromatography; S7, quantitatively calculate the concentration of dissolved greenhouse gases in the wastewater in S1 based on Henry's law and the gas phase greenhouse gas concentrations measured in S6; In S7, dissolved greenhouse gases include N2O and CH4; The N2O concentration calculation equation is: Where C0 is the concentration of N2O in the water sample, C g is the N2O concentration in the gas phase after headspace equilibrium, C l is the N2O concentration in the liquid phase after headspace equilibrium, P and R are atmospheric pressure and gas constant, respectively; T is absolute temperature, V g and V l are the volumes of the gas phase and liquid phase in the headspace bottle, respectively. A1, A2, A3, and A4 are constants of -165.8806, 222.8743, 92.0792, and -1.48425, respectively; The dissolved CH4 concentration calculation equation is: Where C0 is the CH4 concentration in the water sample, C g is the CH4 concentration in the gas phase after headspace equilibrium, β is the CH4 solubility coefficient, R is the gas state constant, T is the absolute temperature, V m is the molar volume of CH4 under standard conditions, V g and V l are the volumes of the gas phase and liquid phase in the headspace balancer, respectively.

2. The method for monitoring dissolved greenhouse gases in sewage according to claim 1, characterized in that: In S2, the mass fraction of the dilute sulfuric acid solution is 20%.

3. The method for monitoring dissolved greenhouse gases in sewage according to claim 1, characterized in that: In S3, the refrigerator refrigeration temperature is 0℃-4℃.

4. The method for monitoring dissolved greenhouse gases in sewage according to claim 1, characterized in that: In S5, the headspace bottle is placed in a water bath constant temperature shaking box and shaken at 25°C and 150-200r for 20-30 minutes.

5. A monitoring device for dissolved greenhouse gases in sewage, based on the monitoring method for dissolved greenhouse gases in sewage according to any one of claims 1 to 4, characterized in that: include: An open container (3), wherein the bottom of the open container (3) is provided with two bottom plates (6) in a horizontally symmetrical sliding manner, and the top surfaces of the two bottom plates (6) are respectively fixedly connected with a slide seat (7), and the slide seat (7) is arranged at one end of the two bottom plates (6) close to each other, and a slide rod (8) is horizontally slidably connected to the slide seat (7), and one end of the slide rod (8) is fixedly connected to the inner wall of the open container (3), and a spring (9) is fixedly connected between the slide seat (7) and the inner wall of the open container (3), and the spring (9) is sleeved on the slide rod (8); A long rod (1), the long rod (1) is vertically arranged in the open container (3), the bottom end of the long rod (1) is hinged with two hinged rods, the two hinged rods are respectively hinged with the sliding seats (7) on the top surfaces of the two bottom plates (6), the upper limit position of the long rod (1) is slidably connected with a filter screen (2), the filter screen is slidably matched with the inner wall of the open container (3); the outer wall of the long rod (1) is threadedly connected with a threaded sleeve, and the threaded sleeve is rotatably connected to the top of the filter screen (2); A connecting pipe (5) is horizontally fixedly connected to the side wall of the open container (3), and a valve (4) is provided on the connecting pipe (5).

6. The monitoring device for dissolved greenhouse gases in sewage according to claim 5, characterized in that: The long rod (1) is provided with scale lines.

7. The monitoring device for dissolved greenhouse gases in sewage according to claim 5, characterized in that: The long rod (1) is sleeved with a marking ring (10).

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