CN115165994A - A kind of measuring device and method of nitrous oxide emission from sewage treatment plant - Google Patents

Abstract

The invention discloses a device for measuring nitrous oxide emission of a sewage treatment plant, belonging to the technical field of biological sewage treatment technology and carbon emission monitoring, and comprising a reaction tank, a gas collecting chamber, a gas pump, a gas flowmeter, a dehumidification chamber, a PLC (programmable logic controller), a gas-phase nitrous oxide analyzer, a nitrous oxide microelectrode, a liquid-phase nitrous oxide measuring host and a computer; the gas collecting chamber is fixed above the liquid level of the reaction tank, the gas collecting chamber is connected with a gas pump, the gas pump is connected with a gas flowmeter, the gas flowmeter is connected with a dehumidifying chamber, the dehumidifying chamber is connected with a gaseous nitrous oxide analyzer, and the dehumidifying chamber is also electrically connected with a PLC (programmable logic controller); the nitrous oxide microelectrode is connected with the liquid phase nitrous oxide measurement host, and the nitrous oxide microelectrode is arranged below the liquid surface of the reaction tank; the invention realizes high automation by utilizing the PLC, and can realize the long-term continuous online monitoring of liquid phase and gas phase nitrous oxide in the reaction tank of the sewage treatment plant.

Description

A kind of measuring device and method of nitrous oxide emission from sewage treatment plant

technical field

The invention belongs to the technical field of sewage biological treatment technology and carbon emission monitoring technology, and particularly relates to a measuring device and method for nitrous oxide emission in a sewage treatment plant.

Background technique

Nitrous oxide is a strong greenhouse gas that persists in the atmosphere for up to 116 years, not only showing a strong greenhouse effect (265 times that of carbon dioxide), but also depleting stratospheric ozone. In the context of the current "dual carbon policy", the monitoring of nitrous oxide emissions and the formulation of relevant emission reduction policies are of great practical significance. Sewage treatment plants are a typical anthropogenic source of nitrous oxide, accounting for 3.7% of the global total annual nitrous oxide emissions. At the same time, nitrous oxide emissions are also an important part of the carbon footprint of sewage treatment plants (accounting for as high as 83%). For the monitoring of nitrous oxide emissions from sewage treatment plants, sampling off-line analysis is generally used at present. First, sampling is carried out at a fixed point in the reaction tank, and then a gas chromatograph equipped with an electron capture detector (ECD) is used to detect the nitrous oxide concentration of the sample. Liquid samples also require complex pretreatment to obtain dissolved nitrous oxide gas for concentration determination. Sampling off-line analysis requires high sampling cost, and the detection process is relatively complicated, which is only suitable for short-term monitoring. Moreover, due to the significant difference in the production of nitrous oxide in different operating periods of sewage treatment plants, the existing measurement methods cannot be used for continuous monitoring. This estimated total often has large errors and low data reliability. Therefore, it is very important to explore a stable, reliable, and labor-saving long-term online measurement device and method for nitrous oxide emissions from sewage treatment plants, which has high practical significance for quantifying and evaluating carbon emissions in sewage treatment plants. Therefore, how to provide a measuring device and method for nitrous oxide emission from a sewage treatment plant is an urgent problem to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a measuring device and method for nitrous oxide discharge in a sewage treatment plant, so as to solve the above-mentioned technical problems. The device and method can simultaneously carry out long-term continuous online monitoring of nitrous oxide in the liquid phase and gas phase in the reaction tank, the device has a simple structure, saves labor costs, the measurement results are accurate and reliable, and provides data for calculating the nitrous oxide discharge and output of a sewage treatment plant It has good application prospects.

In order to achieve the above object, the present invention adopts the following technical solutions:

A device for measuring nitrous oxide emissions in a sewage treatment plant, comprising a reaction pool, a gas collection chamber, an air pump, a gas flow meter, a dehumidification chamber, a PLC controller, a gas-phase nitrous oxide analyzer, a nitrous oxide microelectrode, and a liquid-phase oxidation device. Nitrous measurement host and computer; the gas collection chamber is arranged above the liquid surface of the reaction pool, the gas collection chamber is connected with an air pump, the air pump is connected with a gas flowmeter, and the gas flowmeter is connected with the air inlet of the dehumidification chamber , the gas outlet of the dehumidification chamber is connected to the gas phase nitrous oxide analyzer, the dehumidification chamber is also electrically connected to the PLC controller, and the gas phase nitrous oxide analyzer is connected to the gas outlet; the nitrous oxide microelectrode is connected to the liquid The phase nitrous oxide measurement hosts are connected to each other, the liquid phase nitrous oxide measurement hosts are electrically connected to the computer, and the nitrous oxide microelectrodes are arranged below the liquid surface of the reaction tank.

Further, the dehumidification chamber includes a vent, an exhaust fan, a thermometer, a color-changing silica gel desiccant, an observation window, a porous tray, an electric heating wire and a humidity sensor. A color-changing silica gel desiccant is arranged below the air fan, a porous tray is installed at the bottom end of the color-changing silica gel desiccant, an electric heating wire is installed at the bottom end of the porous tray, and a humidity sensor is installed at the air outlet of the dehumidification chamber, An observation window is installed in the dehumidification chamber, and a thermometer is installed inside the dehumidification chamber.

Further, the gas collection chamber includes a suction port, a fan, an upper floating ring, an air pressure balance hole, a gas collection box and a fixing ring. A fan is installed at the inner top of the gas collection box to ensure that the collected gas is mixed evenly, and the gas collected The top of the box is provided with an air suction port, the side of the gas collection box is equipped with an air pressure balance hole to ensure that the internal and external air pressures are consistent, and a fixing ring is installed outside the gas collection box to fix the gas collection chamber on the liquid surface of the reaction pool through a rope , an upper floating ring is installed on the outside of the gas collection box, and a suction port is arranged on the top to extract gas samples for subsequent analysis.

Further, the dehumidification chamber, the PLC controller, the gas phase nitrous oxide analyzer, the liquid phase nitrous oxide measurement host and the computer are all arranged indoors, the number of the dehumidification chambers is multiple, and the gas flowmeters are respectively associated with the multiple chambers. The air inlets of the dehumidification chambers are communicated with each other, and the gas-phase nitrous oxide analyzer is communicated with the air outlets of the dehumidification chambers respectively.

Further, during the operation of the device, a plurality of dehumidification chambers are used alternately, and at the same time, only one of the plurality of dehumidification chambers is used for dehumidification.

Further, the dehumidifying chamber is provided with a color-changing silica gel desiccant, which reduces the relative humidity of the gas to be measured from 90% RH to 42% RH-55% RH; when the humidity sensor in the dehumidifying chamber shows that the relative humidity value is higher than At 55% RH, immediately close the current dehumidification chamber passage, and open the electric heating wire, exhaust fan and vent valve to dry the discolored silica gel desiccant, restore the dehumidification function, and discharge the generated water vapor. Open another dehumidification chamber to continue dehumidifying the gas to be tested.

Further, the data of the humidity sensor will be transmitted to the PLC controller in real time, and the electric heating wire, the exhaust fan, the valve of the vent and the passage of the gas inlet and outlet of the dehumidification chamber are all controlled by the PLC controller to open. close.

Further, a gas sampling bag is connected to the gas outlet of the gas-phase nitrous oxide analyzer, gas samples are collected, and a nitrous oxide isotope analyzer is used to further analyze the generation path of nitrous oxide.

A method for measuring nitrous oxide discharge from a sewage treatment plant, comprising the following steps:

Step 1: Fix the nitrous oxide microelectrode below the liquid level of the water outlet of the reaction tank, fix the gas collection chamber above the liquid level of the reaction tank, and measure the connection of each part of the pipeline and circuit of the device; by fixing the nitrous oxide microelectrode and the liquid phase The nitrous oxide measuring host measures the liquid phase nitrous oxide concentration, and the gas collection chamber is used to extract gas samples to detect the gas phase nitrous oxide concentration;

Step 2: use a computer to read the concentration of liquid nitrous oxide in the reaction tank;

Step 3: measure the concentration of gas-phase nitrous oxide by a gas-phase nitrous oxide analyzer;

Step 4: After the measuring device is connected, the gas flow meter is set to 1-5L/min, the gas pump is turned on, and the gas collected in the gas collection chamber first enters the dehumidification chamber to reduce the gas humidity to between 42%RH-55%RH , and then enter the gas phase nitrous oxide analyzer for concentration measurement.

Further, the measurement steps of gas phase nitrous oxide in the reaction tank are as follows: the gas flow meter is set to 1-5L/min, the air pump is turned on, the gas sample in the gas collection chamber is drawn into the dehumidification chamber to reduce the gas humidity, and then the gas phase nitrous oxide is entered. The analyzer performs concentration determinations.

Compared with the prior art, the present invention has the following beneficial effects:

In the invention, the dehumidification chamber is arranged to significantly reduce the humidity of the gas to be measured, the interference of water vapor on the detection of nitrous oxide is eliminated, and the measurement accuracy is improved, and at the same time, the PLC controller is used to realize on-line continuous monitoring of the gas phase and liquid phase nitrous oxide in the reaction tank. , high degree of automation, saving labor costs, and providing a reliable data basis for estimating nitrous oxide emissions and production in sewage treatment plants.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to the provided drawings without creative work.

FIG. 1 is a schematic structural diagram of the present invention.

2 is a schematic cross-sectional view of a gas collection chamber.

Figure 3 is a schematic diagram of a gas-phase nitrous oxide determination process and device.

Among them, 1-reaction tank, 2-gas collection chamber, 2.1-air extraction port, 2.2-fan, 2.3-upper floating ring, 2.4-air pressure balance hole, 2.5-gas collection box, 2.6-fixing ring, 3-air pump, 4- Gas flow meter, 5-dehumidification chamber, 5.1-vent, 5.2-exhaust fan, 5.3-thermometer, 5.4-color-changing silica gel desiccant, 5.5-observation window, 5.6-porous tray, 5.7-electric heating wire, 5.8-humidity Sensor, 6-PLC controller, 7-gas phase nitrous oxide analyzer, 8-gas outlet, 9-nitrous oxide microelectrode, 10-liquid phase nitrous oxide measurement host, 11-computer.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

As shown in FIG. 1 , the present invention provides a measuring device for nitrous oxide emission in a sewage treatment plant. The measuring device includes a reaction cell 1, a gas collection chamber 2, an air pump 3, a gas flow meter 4, a dehumidification chamber 5, a PLC controller 6, a gas-phase nitrous oxide analyzer 7, a nitrous oxide microelectrode 9, and a liquid-phase nitrous oxide. Nitrogen measurement host 10 and computer 11 .

As shown in Figure 2, the gas collection chamber 2 is composed of a gas collection box 2.5 and an upper floating ring 2.3. The gas collection box 2.5 is provided with an air pressure balance hole 2.4 on the side to ensure the same air pressure inside and outside. To ensure that the collected gas is mixed evenly, a fixing ring 2.6 is installed on the outside, and a rope is used to fix the gas collection box 2.5 on the liquid surface of the reaction tank 1 through the fixing ring 2.6. The top is provided with a suction port 2.1 for extracting gas samples for subsequent analysis. The fan 2.2 is a small fan.

In this embodiment, the upper floating ring 2.3 has good air tightness, is made of lightweight materials, and is bonded to the outside of the gas collection box 2.5 to ensure that the gas collection chamber 2 can float on the liquid surface.

In this embodiment, the lower part of the gas collection box 2.5 is a cylindrical body, and the upper part is a conical body, forming an inner cavity for collecting gas.

As shown in Figure 3, the dehumidification chamber 5 is provided with a gas inlet at the top and a gas outlet at the bottom. The gas inlet of the dehumidification chamber 5 is communicated with the gas flow meter 4, and the gas outlet is connected with the gas phase nitrous oxide. Analyzer 7 is connected. The top of the dehumidifying chamber 5 is provided with a vent 5.1, an exhaust fan 5.2 and a thermometer 5.3, and the bottom end is provided with a humidity sensor 5.8 and an electric heating wire 5.7, a porous tray 5.6 is arranged above the electric heating wire 5.7, and a discoloration is placed above the porous tray 5.6. Silica gel desiccant 5.4, an observation window 5.5 is provided on the side of the dehumidification chamber 5 so that the color of the discolored silica gel desiccant 5.4 can be observed at any time to judge its dehumidification capability.

In this embodiment, the number of the dehumidification chambers 5 is multiple, the gas inlets of the multiple dehumidification chambers 5 are respectively communicated with the gas flow meter 5, and the gas outlets of the multiple dehumidification chambers 5 are respectively communicated with the gas-phase nitrous oxide analyzer 7 .

In this embodiment, during the operation of the system, a plurality of dehumidification chambers 5 are used alternately, and at the same time, only one of the plurality of dehumidification chambers 5 is used for dehumidification.

In this embodiment, when the humidity sensor 5.8 of the dehumidification chamber 5 shows that the relative humidity value is higher than 55% RH, the current passage of the dehumidification chamber 5 is closed immediately, and the electric heating wire 5.7, the exhaust fan 5.2 and the valve of the vent 5.1 are opened to dry Dry discolored silica gel desiccant 5.4 to restore the dehumidification function, discharge the generated water vapor, and open the passage of another dehumidification chamber to continue to dehumidify the gas to be measured.

In this embodiment, the data of the humidity sensor 5.8 will be transmitted to the PLC controller 6 in real time, and the electric heating wire 5.7, the exhaust fan 5.2, the valve of the vent 5.1 and the gas inlet and outlet of the dehumidification chamber 5 are all controlled by the PLC The controller 6 controls the opening and closing; the PLC controller is used to achieve a high degree of automation, saving labor costs, and can realize long-term continuous online monitoring of the liquid phase and gas phase nitrous oxide in the reaction tank of the sewage treatment plant at the same time, in order to estimate the nitrogen oxide in the sewage treatment plant. Nitrogen emissions provide a reliable data basis with good practical significance and application prospects.

A method for measuring nitrous oxide discharge from a sewage treatment plant, comprising the following steps:

Step 1: Fix the nitrous oxide microelectrode 9 below the liquid level of the water outlet of the reaction tank 1, fix the gas collection chamber 2 above the liquid level of the reaction tank 1, and measure the connection of each part of the pipeline and circuit of the device; The electrode 9 and the liquid phase nitrous oxide measuring host 10 measure the liquid phase nitrous oxide concentration, and the gas collection chamber 2 is used to extract gas samples to detect the gas phase nitrous oxide concentration;

Step 2: use the computer 11 to read the concentration of liquid nitrous oxide in the reaction tank 1;

Step 3: measure the concentration of gas-phase nitrous oxide by gas-phase nitrous oxide analyzer 7;

Step 4: After the measuring device is connected, the gas flow meter 4 is set to 1-5L/min, the gas pump 3 is turned on, and the gas collected in the gas collection chamber 2 first enters the dehumidification chamber 5 to reduce the gas humidity to 42% RH-55 %RH, and then enter the gas phase nitrous oxide analyzer 7 for concentration measurement.

Example 1:

This example is an example of nitrous oxide emission measurement in a sewage treatment plant. According to previous research, there are two main ways of nitrous oxide emission in mainstream processes of sewage treatment plants: gas-phase nitrous oxide escapes from the water surface with aeration, and dissolved nitrous oxide enters the environment with the effluent. The gas phase nitrous oxide in the aeration tank and the liquid phase nitrous oxide in the effluent are used to estimate the nitrous oxide emission of the sewage treatment plant. The nitrous oxide microelectrode 9 is fixed below the effluent liquid level, and the liquid phase nitrous oxide concentration in the effluent water is directly measured by the nitrous oxide microelectrode 9 and the liquid phase nitrous oxide measuring host 10, and the measured concentration is read on the computer 11. value. The measurement process of gas-phase oxidation subconcentration in the aeration tank is as follows: the gas collected in the gas collection chamber 2 above the liquid surface of the aeration reaction tank is extracted by the air pump 3, and the gas flow meter 4 is adjusted to 1-5L/min. The gas to be tested enters the first dehumidification chamber 5 through a1 and a2 of the three-way valve, and the humidity of the gas to be tested after absorbing moisture by the color-changing silica gel desiccant drops to between 42%RH-55%RH, and then passes through the three-way valve b1 and b3 enter the gas phase nitrous oxide analyzer 7 for concentration detection, and the detected gas is discharged from the gas outlet 8 . The color-changing silica gel desiccant 5.4 of the first dehumidification chamber 5 will gradually lose its dehumidification ability with the extension of the dehumidification time. When the humidity sensor 5.8 shows that the relative humidity of the gas to be measured is higher than 55%RH, the PLC controller 6 will automatically shut down a2 access and b1 access, and open the electric heating wire 5.7, the exhaust fan 5.2 and the first valve of the vent 5.1 to dry the discolored silica gel desiccant, restore the dehumidification function, and discharge the generated water vapor, and open the a3 access and b2 at the same time. The gas to be tested enters the second dehumidification chamber 5 to continue its dehumidification. The dehumidified gas to be tested enters the gas phase nitrous oxide analyzer 7 through b2 and b3 of the three-way valve for concentration detection. The nitrous oxide discharge amount of the sewage treatment plant can be estimated by processing and summing the obtained continuous concentration values of the gas phase nitrous oxide in the aeration tank and the effluent liquid phase nitrous oxide in a period of time.

By setting the dehumidification chamber, the interference of water vapor on the detection of nitrous oxide is avoided, and the continuous online monitoring of nitrous oxide in the sewage treatment plant is realized by using the PLC controller 6, and the dynamic nitrous oxide emission data that changes with the operation cycle can be obtained. , to provide a reliable data basis for the estimation of nitrous oxide production in sewage treatment plants and the formulation of emission reduction measures.

Example 2:

This example is an example of the measurement of nitrous oxide production in different treatment units of a sewage treatment plant. This embodiment is basically the same as Embodiment 1, the difference is that the nitrous oxide microelectrode 9 and the gas collection chamber 2 are arranged in the same processing unit. The placement and flow of the measuring device are shown in Figure 1-3. The nitrous oxide output of the treatment unit can be estimated by processing and summing the continuous concentration values of nitrous oxide in the gas phase and liquid phase of a certain treatment unit within a certain period of time.

By simply adjusting the setting positions of the nitrous oxide microelectrode 9 and the gas collection chamber 2, the nitrous oxide output of different treatment units in the sewage treatment plant can be obtained, which is beneficial to analyze the main sources of nitrous oxide and investigate the carbon footprint of the sewage treatment plant. Important practical significance and application prospects.

Example 3:

This example is an example of the measurement of nitrous oxide accumulation in an anoxic tank of a sewage treatment plant. Basically the same as Example 1, the difference is that the gas-phase nitrous oxide measuring device is no longer used, and the nitrous oxide microelectrode 9 only needs to be set below the liquid surface of the anoxic tank. The liquid-phase nitrous oxide concentration in the anoxic tank is measured by the nitrous oxide microelectrode 9 and the liquid-phase nitrous oxide measuring host 10 , and the measured concentration value is read on the computer 11 . According to the obtained long-term continuous data, the accumulation of nitrous oxide in the anoxic pool and its dynamic law with the change of the operating cycle can be analyzed.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. The device for measuring the nitrous oxide emission of the sewage treatment plant is characterized by comprising a reaction tank (1), a gas collecting chamber (2), an air pump (3), a gas flow meter (4), a dehumidifying chamber (5), a PLC (programmable logic controller) (6), a gas phase nitrous oxide analyzer (7), a nitrous oxide microelectrode (9), a liquid phase nitrous oxide measuring host (10) and a computer (11);

the device comprises a reaction tank (1), a gas collecting chamber (2), a gas flow meter (4), a dehumidifying chamber (5), a gas outlet of the dehumidifying chamber (5), a gas phase nitrous oxide analyzer (7), a PLC (programmable logic controller) controller (6), a gas collecting chamber (2), a gas pump (3), a gas flow meter (4), a gas inlet of the dehumidifying chamber (5), a gas outlet (8), a gas-phase nitrous oxide analyzer and a gas collecting chamber (2), wherein the gas collecting chamber (2) is fixed above the liquid level of the reaction tank (1) through a rope; the nitrous oxide microelectrode (9) is connected with a liquid phase nitrous oxide measuring host (10) in an interconnection mode, the liquid phase nitrous oxide measuring host (10) is electrically connected with a computer (11), and the nitrous oxide microelectrode (9) is arranged below the liquid level of the reaction tank (1).

2. The device for measuring nitrous oxide emission of sewage treatment plant according to claim 1, characterized in that: dehumidification room (5) are including vent (5.1), air discharge fan (5.2), thermometer (5.3), color-changing silica gel drier (5.4), observation window (5.5), porous tray (5.6), electric heating wire (5.7) and humidity transducer (5.8), air discharge fan (5.2) is installed to vent (5.1) bottom, air discharge fan (5.2) below is provided with color-changing silica gel drier (5.4), porous tray (5.6) are installed to the bottom of color-changing silica gel drier (5.4), electric heating wire (5.7) are installed to the bottom of porous tray (5.6), the department of gas outlet of dehumidification room (5) installs humidity transducer (5.8), install observation window (5.5) except that dehumidification room (5), except that dehumidification room (5) internally mounted has thermometer (5.3).

3. The device for measuring nitrous oxide emission of sewage treatment plant according to claim 1, characterized in that: the gas collection chamber (2) comprises an air suction opening (2.1), a fan (2.2), an upper floating ring (2.3), a gas pressure balance hole (2.4), a gas collection box (2.5) and a fixing ring (2.6), wherein the fan (2.2) is installed at the top end of the inside of the gas collection box (2.5) to ensure that the collected gas is uniformly mixed, the top end of the gas collection box (2.5) is provided with the air suction opening (2.1) for sucking a gas sample for subsequent analysis, the gas pressure balance hole (2.4) is installed at the side part of the gas collection box (2.5) to ensure that the internal and external gas pressures are consistent, the fixing ring (2.6) is installed outside the gas collection chamber (2) and used for fixing the gas collection chamber (2) on a reaction liquid level pool through a rope, and the upper floating ring (2.3) is installed outside the gas collection box (2.5).

4. The device for measuring nitrous oxide emission of sewage treatment plant according to claim 2, characterized in that: dehumidification room (5), PLC controller (6), gaseous phase nitrous oxide analysis ware (7), liquid phase nitrous oxide measure host computer (10) and computer (11) all set up indoor, dehumidification room (5) quantity is a plurality of, gas flowmeter (4) communicate with the air inlet of a plurality of dehumidification rooms (5) respectively, gaseous phase nitrous oxide analysis ware (7) communicate with the gas outlet of a plurality of dehumidification rooms (5) respectively.

5. The device for measuring nitrous oxide emission of sewage treatment plant according to claim 4, characterized in that: during the operation of the measuring device, the plurality of dehumidifying chambers (5) are used alternately, and only one of the plurality of dehumidifying chambers (5) is used for dehumidifying at the same time.

6. The device for measuring nitrous oxide emission of sewage treatment plant according to claim 5, characterized in that: a chromophoric silica gel desiccant (5.4) is provided in the dehumidification chamber (5) to reduce the relative humidity of the gas to be measured from 90% RH to 42% RH-55% between RH; when the humidity sensor (5.8) in the dehumidification chamber (5) displays that the relative humidity value is higher than 55 percent RH, the current path of the dehumidification chamber (5) is closed immediately, and the electric heating wire (5.7), the exhaust fan (5.2) and the valve of the ventilation opening (5.1) are opened to dry the allochroic silica gel desiccant (5.4), so that the dehumidification function is recovered, the generated water vapor is exhausted, and simultaneously the path of the other dehumidification chamber (5) is opened to continue to dehumidify the gas to be tested.

7. The device for measuring nitrous oxide emission of sewage treatment plant according to claim 6, characterized in that: the data of the humidity sensor (5.8) are transmitted to the PLC controller (6) in real time, and the electric heating wire (5.7), the exhaust fan (5.2), the valve of the vent (5.1) and the passage of the gas inlet and outlet of the dehumidification chamber (5) are controlled to be opened and closed by the PLC controller (6).

8. A method for measuring nitrous oxide emission of a sewage treatment plant, which is realized by using the measuring device of any one of claims 1 to 7, and is characterized by comprising the following steps:

step 1: fixing a nitrous oxide microelectrode (9) below the liquid level of effluent of the reaction tank (1), fixing a gas collection chamber (2) above the liquid level of the reaction tank (1), and determining the connection of pipelines and lines of each part of the device; the concentration of the liquid-phase nitrous oxide is measured through a fixed nitrous oxide microelectrode (9) and a liquid-phase nitrous oxide measuring host (10), and a gas collecting chamber (2) is used for extracting a gas sample to detect the concentration of the gas-phase nitrous oxide;

step 2: reading the concentration of liquid-phase nitrous oxide in the reaction cell (1) by using a computer (11);

and step 3: determining the concentration of gaseous nitrous oxide by means of a gaseous nitrous oxide analyzer (7);

and 4, step 4: after the measurement device is connected, the gas flow meter (4) is set to 1-5L/min, the gas pump (3) is opened, and the gas collected in the gas collection chamber (2) first enters the dehumidification chamber (5) to reduce the gas humidity to 42-55% RH, and then enters the gas phase nitrous oxide analyzer (7) to perform concentration measurement.

9. The method for measuring nitrous oxide emission of sewage treatment plant according to claim 8, characterized in that the step of measuring gaseous phase nitrous oxide in the reaction tank (1) is as follows: the gas flow meter (4) is set to be 1-5L/min, the gas pump (3) is opened, the gas sample in the gas collection chamber (2) is pumped into the dehumidification chamber (5) to reduce the humidity of the gas, and then the gas sample enters the gas phase nitrous oxide analyzer (7) to be subjected to concentration measurement.

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