A bioaerosol and volatile organic compound generation, equilibration, and co-exposure system and methods of use thereof

Abstract

The application discloses a bioaerosol and volatile organic compound generation, equilibrium and co-exposure system and a use method thereof. The system comprises a co-exposure equilibrium box, a volatile organic compound gas equilibrium box and a bioaerosol equilibrium box connected with the co-exposure equilibrium box through a pipeline system, a bioaerosol collecting device and the like. By using the system, the generation and equilibrium of multi-component and multi-gradient VOCs and multi-species and multi-concentration bioaerosols can be rapidly and real-timely controlled by regulating the gas path ratio of VOCs gas and bioaerosol, changing the types and concentrations of microorganisms and VOCs in the bioaerosol and the like, real-time regulation of VOCs exposure bioaerosol is realized, the release of different concentrations, different types and multi-type VOCs and the generation of different types of bioaerosols in different natural scenes are simulated, the interaction between VOCs and bioaerosols is evaluated, and the subsequent treatment of VOCs and bioaerosols is facilitated.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ecological environment. More particularly, it relates to a biological aerosol and volatile organic compound generation, equilibrium and co-exposure system and a method of using the same. BACKGROUND

[0002] Biological aerosol refers to aerosol containing biological ions such as bacteria and viruses, which, in addition to the characteristics of general aerosol, is also prone to cause a variety of respiratory diseases. Volatile organic compounds (VOCs) include industrial halogenated hydrocarbons, unsaturated hydrocarbons and benzene series caused by incomplete combustion, which can damage the nervous system and organs such as liver and kidney.

[0003] Both biological aerosol and VOCs pollution are the focus of researchers in the field of atmospheric environmental science. However, the field currently usually only evaluates the emission characteristics of biological aerosol or VOCs, and assesses the health risks of biological aerosol and VOCs through the emission content and species of single biological aerosol and VOCs, and the interaction mechanism of biological aerosol and VOCs is unknown, and there are few reports on the interaction of VOCs exposure in biological aerosol. However, in the fields of municipal solid waste disposal, sewage treatment and industrial production, biological aerosol and VOCs are usually released simultaneously. For example, in the processes of aeration treatment in sewage treatment plants and decomposition of waste in waste landfills, not only a large amount of VOCs with irritating odor will be produced, but also a large amount of biological aerosol containing pathogenic bacteria such as Staphylococcus aureus, Escherichia coli, Legionella, Salmonella and Mycobacterium tuberculosis will be released. Such mixed pollutants will spread to the surrounding environment with the diffusion of the atmosphere and the influence of meteorological conditions, which will bring adverse effects on human health, etc.

[0004] When biological aerosol and VOCs coexist, on the one hand, microorganisms and VOCs will influence each other, and exploring the mutual influence of the two is conducive to the subsequent treatment of their mixed pollutants; on the other hand, VOCs will act as an environmental stress source to select and cause microorganisms to evolve, thereby leading to more serious health risks. In addition to short-term observation of the mutual influence of the two, long-term effects of the two also need to be evaluated to avoid greater safety hazards. Although there are reports of devices that can capture aerosol and VOCs at the same time, they can only be used for collection and cannot be used to observe the mutual influence of biological aerosol and VOCs. That is, there is currently a lack of a biological aerosol and volatile organic compound co-generation, equilibrium and exposure system. SUMMARY

[0005] The present application provides a biological aerosol and volatile organic compound co-generation, equilibrium and exposure system and a method of using the same to solve the technical problems in the prior art.

[0006] The first object of the present application is to provide a system for generating, balancing and co-exposing bioaerosols and volatile organic compounds.

[0007] The second object of the present application is to provide an application of the system.

[0008] The above objects of the present application are achieved by the following technical solutions.

[0009] The present application provides a system for generating, balancing and co-exposing bioaerosols and volatile organic compounds (VOCs). The system can simulate the co-generation and dynamic balance of different types and concentrations of bioaerosols and VOCs, and can flexibly adjust the types, exposure concentrations and exposure times of VOCs, construct a VOCs exposure bioaerosol interaction system, and realize the physiological state activity evaluation of bioaerosols under VOCs exposure, so as to facilitate the treatment of bioaerosol and VOCs mixed pollutants.

[0010] Specifically, the system for generating, balancing and co-exposing bioaerosols and volatile organic compounds comprises a co-exposure balancing box, a volatile organic compound gas balancing box and a bioaerosol balancing box connected to the co-exposure balancing box through a pipeline system, and a control device for controlling the operation of the system.

[0011] The pipeline system comprises an input path connected to the volatile organic compound gas balancing box and the bioaerosol balancing box, respectively, and an output path connecting the volatile organic compound gas balancing box and the bioaerosol balancing box to the co-exposure balancing box; the input path is sequentially provided with an air compressor, a flow controller and an air filter, and the input path connected to the volatile organic compound gas balancing box is further provided with a volatile organic compound generator, and the input path connected to the bioaerosol balancing box 3 is further provided with a bioaerosol generator.

[0012] The co-exposure balancing box is further connected to a bioaerosol collection device; the volatile organic compound gas balancing box is further connected to a volatile organic compound detector; and the bioaerosol balancing box 3 is further connected to a bioaerosol particle real-time monitor.

[0013] Specifically, the input path and / or output path in the pipeline system contains at least one branch. That is, in the most basic pipeline system of the present application, the input path and the output path contain only one passage, but for the purpose of increasing flow, etc., the skilled person can add branches.

[0014] As in the specific embodiments of the present application, the input path in the pipeline system comprises at least one branch. Specifically, the branch of the input path is branched from the air compressor, and a flow controller and an air filter are arranged in sequence on the branch, and clean air is input into the balance tank connected thereto through the branch for dilution or adjustment of the concentration of bio-aerosol or VOCs gas.

[0015] Optionally, the addition of the branch in the pipeline system is realized by using a multi-way pipe and a connector connected to the multi-way pipe, and the number of channels of the input path or the output path can be flexibly adjusted to construct a dendritic pipeline system.

[0016] Specifically, the pipeline system is further provided with an air valve for controlling the entry and exit of aerosol or gas.

[0017] Optionally, the air valve is a ball valve.

[0018] Specifically, each pipeline in the pipeline system is connected to the tank body through a fluid inlet and outlet.

[0019] Specifically, the co-exposure balance tank, the volatile organic compound gas balance tank and the bio-aerosol balance tank are each provided with a turbulence device.

[0020] Specifically, the co-exposure balance tank, the volatile organic compound gas balance tank and the bio-aerosol balance tank are each provided with an exhaust pressure relief device.

[0021] Optionally, the turbulence device is a fan, which is arranged inside the balance tank, and the VOCs and bio-aerosol are quickly and uniformly distributed in the balance tank by disturbing the gas inside the balance tank.

[0022] Optionally, the fan is a magnetic fan.

[0023] Preferably, the fan blades are covered with an anti-sticking coating, which can reduce the adhesion / adsorption of microorganisms and VOCs, reduce the loss of bio-aerosol and VOCs, and maintain the activity of bio-aerosol.

[0024] Similarly, the inner wall of the tank body of each balance tank is covered with an anti-sticking coating.

[0025] Optionally, the coating is a polytetrafluoroethylene coating or a silicone coating.

[0026] Optionally, the exhaust pressure relief device is an exhaust pressure relief valve; the gas pressure in the balance tank is controlled by discharging a part of the gas through the exhaust pressure relief valve, and the discharged VOCs and bio-aerosol are discharged after harmless treatment.

[0027] Specifically, the bio-aerosol generator is a liquid microorganism aerosol generator.

[0028] Optionally, the liquid microorganism aerosol generator is a three-hole biological aerosol generator, a six-hole biological aerosol generator or a twenty-four-hole biological aerosol generator.

[0029] Specifically, the VOCs detector is connected with the box through the fluid inlet and outlet (used as a sampling port) provided on the box and used for monitoring the concentration of VOCs in the VOCs balance box in real time, monitoring whether the balance box is in a balanced state; similarly, the biological aerosol particle real-time monitor is also connected with the box through the fluid inlet and outlet provided on the box and used for monitoring the particle concentration of the biological aerosol in real time, for monitoring whether the balance box is in a balanced state.

[0030] Specifically, when the detection values of the VOCs detector at the multiple sampling ports equidistantly distributed on the vertical side of the box remain stable and consistent, it indicates that the balance box is in a balanced state. Similarly, when the detection values of the biological aerosol particle real-time monitor at the multiple sampling ports equidistantly distributed on the vertical side of the box remain stable and consistent, it indicates that the balance box is in a balanced state.

[0031] Specifically, the number of the sampling ports is at least 3.

[0032] Specifically, the control device is a circuit control switch.

[0033] The application also provides a method for using the system, or a method for testing the interaction between microorganism aerosol and volatile organic compounds by using the system, comprising the following steps:

[0034] S1. A solution of the volatile organic compound to be tested is added to the sampling needle of the volatile organic compound generator, and the pipeline system is used to make the volatile organic compound generator generate volatile organic compounds and enter the volatile organic compound gas balance box, after the box is filled with volatile organic compounds, the volatile organic compound generator is closed, and the volatile organic compounds in the box enter a dynamic balance;

[0035] S2. The suspension of the microorganism to be tested is placed in the liquid bottle of the biological aerosol generator, and the pipeline system is used to make the biological aerosol generator generate microorganism aerosol and enter the biological aerosol balance box, after the box is filled with microorganism aerosol, the biological aerosol generator is closed, and the aerosol in the box enters a dynamic balance;

[0036] S3. The volatile organic compounds and the microbial aerosol in dynamic balance are simultaneously introduced into the co-exposure balance box through the output path of the pipeline system for dynamic balance, the microbial aerosol sample is collected by using the biological aerosol collection device and is enriched, gradient dilution and plate culture are performed on the enriched microorganisms, the cultivable number of the microorganisms in the sample is calculated in combination with the dilution multiple, and the change in the cultivable number of the microorganisms is observed, so as to observe the influence of the volatile organic compounds on the microbial aerosol.

[0037] The calculation formula of the cultivable number is as follows:

[0038]

[0039] Wherein, C 液体浓度 is the cultivable number of the microorganisms counted by dilution and plate.

[0040] Specifically, the preparation method of the microbial suspension is as follows: the preserved microbial strain is inoculated into a culture medium and is cultured until the microorganisms enter the logarithmic growth phase, centrifugation is performed to discard the supernatant, the precipitate is washed with a buffer solution, and the microbial suspension is obtained again by vortexing with the buffer solution, and the concentration of the microbial suspension is 0-10 10 CFU / mL.

[0041] Specifically, the buffer solution is a phosphate solution.

[0042] Specifically, in S3, the collected microbial aerosol sample is enriched by using an ultrafiltration tube, and the enriched sample is eluted from the ultrafiltration membrane by using a physiological saline solution.

[0043] More specifically, the collected biological aerosol sample is enriched by using a centrifugal ultrafiltration tube, and the sample is eluted from the ultrafiltration membrane by using a 0.9% physiological saline solution.

[0044] Specifically, the microorganisms include bacteria, fungi and viruses.

[0045] Specifically, the bacteria are one or more of Escherichia coli, Bacillus, Pseudomonas aeruginosa and Staphylococcus aureus.

[0046] Specifically, the constant flow rate in S2 is 0-50 L / min, and the flushing time is 0-30 min.

[0047] Specifically, the VOCs are one or more of aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, oxygen-containing compounds and organic sulfur compounds.

[0048] Specifically, the temperature of the generator in S2 is 0-300℃, the sample injection flow rate is 0-500 μL / min, and the constant flow rate is 0-100 L / min.

[0049] Specifically, the common equilibrium time in S3 is 0 to 120 minutes, and the collection time is 0 to 200 minutes.

[0050] Specifically, the sampler in S3 may be a liquid impact sampler. After the liquid impact sampler collects the sample, the bioaerosol sample is diluted with a 0.9% saline solution in a continuous gradient and incubated on a nutrient agar plate at 37° C. for 1 to 24 hours.

[0051] Specifically, the gradient dilution is performed at a volume ratio of 1:10.

[0052] The present invention has the following beneficial effects:

[0053] 1. The present invention provides a bioaerosol and volatile organic compound co-existence equilibrium exposure system comprising a co-exposure equilibrium box, a volatile organic compound gas equilibrium box and a bioaerosol equilibrium box connected to the co-exposure equilibrium box through a pipeline system, and a bioaerosol collection device. The system can be used to evaluate the interaction between VOCs and bioaerosols, thereby facilitating the subsequent treatment of VOCs and bioaerosols.

[0054] 2. Based on the system described in the present invention, by regulating the gas path ratio of VOCs and bioaerosols, changing the type and concentration of VOCs and the release and atomization parameters of bioaerosols, the generation balance of multi-component and multi-gradient VOCs and multi-type and multi-concentration bioaerosols can be quickly controlled in real time, thereby achieving real-time regulation of VOCs exposure to bioaerosols, simulating the release of different concentrations, different types and multiple VOCs and the generation of different types of bioaerosols in natural scenes, and achieving real-time dynamic balance between bioaerosols and VOCs. It can also systematically and comprehensively evaluate the effects of VOCs on bioaerosols in natural environments.

[0055] 3. The system described in the present invention is simple to operate, and the results obtained are accurate and intuitive, which is convenient for simulating the interaction between VOCs and bioaerosols in natural scenarios (such as landfills, industrial emissions, sewage treatment plants, and nature). BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic diagram of the system described in Example 1 of the present invention; in the figure, 1 is a co-exposure balance box, 2 is a VOCs gas balance box, 3 is a bioaerosol balance box, 4 is a VOCs generator, 5 is a bioaerosol generator, 6 is a bioaerosol collection device, 7 is a VOCs detector, 8 is a bioaerosol particle real-time monitor, 9 is an air compressor, 10 is a flow disturbance device, 11 is a flow controller, 12 is an air filter, 13 is a fluid inlet and outlet, and 14 is an exhaust pressure relief valve.

[0057] Figure 2 Figure 1 is a schematic diagram of the system described in Example 2 of the present application; Figure 1 is a co-exposure balance tank, 2 is a VOCs gas balance tank, 3 is a bioaerosol balance tank, 4 is a VOCs generator, 5 is a bioaerosol generator, 6 is a bioaerosol collection device, 7 is a VOCs detector, 8 is a bioaerosol particle real-time monitor, 9 is an air compressor, 10 is a turbulence device, 11 is a flow controller, 12 is an air filter, 13 is a fluid inlet and outlet, and 14 is an exhaust pressure relief valve.

[0058] Figure 3 Figure 4 is a graph showing the cultivable number of E. coli bioaerosol exposed to different types of VOCs.

[0059] Figure 4 Figure 5 is a graph showing the cultivable number of E. coli bioaerosol exposed to different concentrations of dimethyl sulfide. DETAILED DESCRIPTION

[0060] The present application is further described in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present application in any form. Unless otherwise specified, the reagents, methods and equipment used in the present application are conventional reagents, methods and equipment in the technical field.

[0061] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0062] Example 1

[0063] This example provides a bioaerosol and VOCs generation, balance and co-exposure system, the schematic diagram of which is shown in Figure 1. As shown in Figure 1, the bioaerosol and VOCs generation, balance and co-exposure system comprises a co-exposure balance tank 1, a VOCs gas balance tank 2 and a bioaerosol balance tank 3 connected to the co-exposure balance tank 1 through a pipeline system, and a control device for controlling the operation of the system. Figure 1 Figure 1 The pipeline system comprises an input path connected to the VOCs gas balance tank 2 and the bioaerosol balance tank 3, respectively, and an output path connecting the VOCs gas balance tank 2 and the bioaerosol balance tank 3 to the co-exposure balance tank 1; the input path is sequentially provided with an air compressor 9, a flow controller 11 and an air filter 12, and the input path connected to the VOCs gas balance tank 2 is further provided with a VOCs generator 4, and the input path connected to the bioaerosol balance tank 3 is further provided with a bioaerosol generator 5.

[0064] The pipeline system comprises an input path connected to the VOCs gas balance tank 2 and the bioaerosol balance tank 3, respectively, and an output path connecting the VOCs gas balance tank 2 and the bioaerosol balance tank 3 to the co-exposure balance tank 1; the input path is sequentially provided with an air compressor 9, a flow controller 11 and an air filter 12, and the input path connected to the VOCs gas balance tank 2 is further provided with a VOCs generator 4, and the input path connected to the bioaerosol balance tank 3 is further provided with a bioaerosol generator 5.

[0065] ​The co-exposure balance box 1 is connected with a biological aerosol collection device 6 and an exhaust pressure relief valve 14, and the inside of the co-exposure balance box 1 is provided with a turbulence device 10; the volatile organic compound gas balance box 2 is connected with a volatile organic compound detector 7 and an exhaust pressure relief valve 14, and the inside of the volatile organic compound gas balance box 2 is provided with a turbulence device 10; the biological aerosol balance box 3 is connected with a biological aerosol particle real-time monitor 8 and an exhaust pressure relief valve 14, and the inside of the biological aerosol balance box 3 is provided with a turbulence device 10.

[0066] In the embodiment, the turbulence device is a magnetic fan. In order to reduce the adhesion / adsorption of microorganisms and VOCs, reduce the loss of biological aerosols and VOCs and maintain the activity of biological aerosols, the fan blades and the inner wall of the box body of each balance box are coated with a polytetrafluoroethylene coating.

[0067] According to the functional division, the system can be divided into a biological aerosol generation balance system, a VOCs gas generation balance system, a co-exposure balance system, a pipeline system for distributing air and a control system. Through the biological aerosol generation balance system, the VOCs gas generation balance system obtains controllable and stable biological aerosols and VOCs gas, and through the co-exposure balance system, the environmental behavior, exposure and prevention and control of biological aerosols under different concentrations, types and multiple VOCs exposure are realized.

[0068] The biological aerosol generation balance system comprises a biological aerosol generator 5, a pipeline system input path for delivering pure air to the biological aerosol generator 5, a biological aerosol balance tank 3 connected to the biological aerosol generator 5, a biological aerosol particle real-time monitor 8 connected to the biological aerosol balance tank 3, a turbulence device 10 arranged in the biological aerosol balance tank 3, and a control device connected to the biological aerosol generator 5, the pipeline system, and the biological aerosol balance tank 3. The pipeline system input path stably and uniformly delivers clean air filtered and sterilized to the biological aerosol generator 5, the biological aerosol generator 5 uniformly disperses the microorganism suspension with biological activity into the clean air to form active biological aerosol, the generated biological aerosol is introduced into the biological aerosol balance tank 3, and the biological aerosol generator 5 can adjust the particle size distribution, concentration, and population of the active biological aerosol in the system; the turbulence device 10 can make the aerosol in the biological aerosol balance tank 3 flow to form uniform and stable biological aerosol gas; the biological aerosol particle real-time monitor 8 connected to the biological aerosol balance tank 3 can monitor the stable balance of the particle concentration of the biological aerosol in the biological aerosol balance tank 3 in real time; and the control device system controls and adjusts the operation of the entire device. The vertical side of the biological aerosol balance tank 3 is provided with at least three equidistantly distributed fluid inlets and outlets 13 used as sampling ports, the biological aerosol particle real-time monitor 8 is connected to the biological aerosol balance tank 3 through the fluid inlets and outlets 13, and when the detection values of the biological aerosol particle real-time monitor 8 at each fluid inlet and outlet 13 are consistent, it indicates that the biological aerosol balance tank 3 is in a balanced state.

[0069] The VOCs generation and balance system comprises a VOCs generator 4, a pipeline system input path for supplying clean air to the VOCs generator, a VOCs balance tank 2 connected to the VOCs generator 4, a VOCs detector 7 connected to the VOCs balance tank 2, a turbulence device 10 arranged on the VOCs balance tank 2, and a control device connected to the VOCs generator 4, the pipeline system, and the VOCs balance tank 2. The pipeline system input path stably and uniformly supplies the clean air filtered and sterilized to the VOCs generator 4. The VOCs generator 4 can generate VOCs gas by heating and vaporizing liquid organic matter. The generated VOCs is supplied to the VOCs balance tank 2. The VOCs generator 4 can adjust the concentration and type of VOCs in the system by changing the amount, type, and sample amount of the liquid organic matter. The turbulence device 10 makes the aerosol in the VOCs balance tank 2 flow, forming a uniform and stable VOCs gas. The VOCs detector 7 connected to the VOCs balance tank 2 can monitor the stability of the concentration of VOCs in the VOCs balance tank in real time. The control device controls and adjusts the operation of the entire device. The vertical side of the VOCs balance tank 2 is provided with at least three equidistant fluid inlets and outlets 13, which are used as sampling ports. The VOCs detector 7 is connected to the VOCs balance tank 2 through the fluid inlets and outlets 13. When the detection values of the VOCs detector at each fluid inlet and outlet 13 are consistent, it indicates that the VOCs balance tank 2 is in a balanced state.

[0070] The co-exposure balance system comprises a co-exposure balance tank 1 connected to a biological aerosol balance tank 3 and a VOCs balance tank 2, a turbulence device 10 arranged on the co-exposure balance tank 1 for uniformly distributing the aerosol and VOCs in the balance tank, and a fluid inlet and outlet 13 arranged on the vertical side of the co-exposure balance tank 1. The biological aerosol collection device 6 connected to the fluid inlet and outlet 13 of the co-exposure balance tank 1 collects the biological aerosol after co-exposure for subsequent analysis.

[0071] The pipeline system comprises an air compressor 9, a flow controller 11 connected to the air compressor 9 in sequence, and a high-efficiency air filter 12 connected to the biological aerosol generator 5 and the VOCs generator 4 through an air quick connector. The air compressor 9 pumps air, and the air pressure provided by the air compressor 9 is stabilized by adjusting the air pressure through an exhaust pressure relief valve 14. The flow of air into the biological aerosol generator 5 or the VOCs generator 4 is changed through the flow controller 11, so as to adjust the concentration of the biological aerosol generator 5 and the VOCs generator 4. The air filter 12 filters out dust, microorganisms, VOCs, and other pollutants in the air to prevent pollution of the biological aerosol and VOCs in the biological aerosol balance tank 3 and the VOCs balance tank 2.

[0072] Example 2

[0073] On the basis of the system described in Embodiment 1, the present embodiment is further improved. Specifically, a branch with a flow controller 11 and a high-efficiency air filter 12 is added to the input path of the pipeline system connected with the VOCs balancing tank 2 and the bioaerosol balancing tank 3, respectively, which is used to input clean air into the balancing tank connected therewith to adjust the concentration of bioaerosol or VOCs gas. The schematic diagram of the bioaerosol and VOCs generation, balancing and co-exposure system described in the present embodiment is shown in Figure 2 .

[0074] Embodiment 3

[0075] The present embodiment uses the system described in Embodiment 2 to test the interaction between E. coli and different kinds of VOCs, and also illustrates the use method of the system described in the present application, which includes the following steps:

[0076] S1. The E. coli strain preserved in a -80°C ultra-low temperature refrigerator is inoculated into a prepared 50 mL nutrient broth medium, and placed in a 37°C, 140 rpm shaker to culture until the E. coli is in the logarithmic growth phase; the bacterial culture is centrifuged at 8000 rpm for 2 min, the supernatant is discarded, the bacterial precipitate is washed with 0.9% NaCl solution for 2 times, then the bacterial precipitate is resuspended, the bacterial concentration is adjusted by using a microplate reader, and the OD600 is 1.0, indicating that the E. coli concentration at this time is 10 9 CFU / mL.

[0077] S2. The E. coli suspension prepared in S1 is transferred to a bioaerosol generator (six-nozzle Collison) in a clean bench, the relative height of the internal device and the liquid surface of the generator is adjusted, the bacterial suspension is aerosolized into the balancing tank with clean air at a flow rate of 12.5 L / min, the tail gas is connected to an air microorganism sampling pump, and the tail gas is pumped to a fume hood at the same flow rate of 12.5 L / min, so that a stable and balanced state is maintained in the balancing tank, the generated bioaerosol is suspended in the balancing tank, and the entire system is continuously flushed with bioaerosol for 5 min until the tank is filled with bioaerosol.

[0078] S3. Take 5 mL of dimethyl trisulfide, dimethyl disulfide, formic acid and ethanethiol liquid with 99% purity from the 4℃ refrigerator, respectively, with the sampling needle of the VOCs generator, fix the sampling needle horizontally on the base, set the sampling needle aperture to 10 mm, set the VOC gas concentration to 140 ppm, connect the VOCs generator with the air pipeline of the air distribution system and check the air tightness and pipeline flow rate, set the reactor temperature to the VOC boiling point, atomize each VOC gas with clean air at a constant flow rate of 5 L / min, make the VOC gas suspended in the VOCs balance tank, and continuously flush the VOCs into the tank to fill the VOC gas and enter the dynamic balance;

[0079] S4. Pass the stable generated (after balance) bioaerosol and the stable generated VOC gas into the sterile co-exposure balance tank to perform dynamic balance, after 10 min of balance, collect the bioaerosol sample for 20 min with the liquid impact sampler, and enrich the collected bioaerosol sample in the centrifugal ultrafiltration tube, centrifuge at 4000 x for 30 min, and elute the sample from the ultrafiltration membrane with 0.9% physiological saline solution.

[0080] S5. Continuously dilute the enriched bioaerosol sample in S4 with 0.9% NaCl solution at a volume ratio of 1:10, record the dilution multiple, inoculate an equal amount of diluent on a nutrient agar plate, incubate at 37℃ for 24 h, and calculate the cultivable number of microorganisms in the sample in combination with the dilution multiple.

[0081] The calculation method of the cultivable number is as follows:

[0082]

[0083] Wherein, C 液体浓度 is the cultivable number of microorganisms counted by dilution plating, and 10000 is a fixed value in unit conversion.

[0084] The cultivable number statistics chart of the E. coli bioaerosol exposed to different types of VOCs is shown in Figure 3 During the experiment, the conditions are the same except that the types of VOCs used are different. As shown in the results in Figure 3 Compared with the blank control, the cultivable concentration of the E. coli bioaerosol exposed to dimethyl disulfide changes very little, indicating that it has little effect on the E. coli bioaerosol, while dimethyl trisulfide, ethanethiol and formic acid have a great effect on the E. coli bioaerosol, and the cultivable number decreases by 2-3 orders of magnitude; among them, formic acid has the greatest effect on the E. coli bioaerosol. As known from this embodiment, the system described in the application can realize autonomous adjustment of the exposure of VOCs types, and can meet the evaluation of the co-exposure of different types of VOCs and bioaerosol in different environmental sites.

[0085] Example 4

[0086] The difference between this embodiment and Example 3 is that, in this embodiment, the VOCs in S3 are set to an injection flow rate of 0.8, 8.9 and 17.7 μL / min, so as to calculate the VOCs concentration of 5 ppm, 50 ppm and 100 ppm, E. coli is selected as the test strain, dimethyl sulfide is selected as the VOCs, and the reactor temperature is set to 60℃, and clean air is used to atomize dimethyl sulfide gas and E. coli bioaerosol at a constant flow rate of 5 L / min to co-equilibrate in the co-exposure equilibrium box for 10 min.

[0087] The sample collection and cultivable number calculation include the following steps:

[0088] S1. The bioaerosol sample is collected into 10 mL of 0.9% physiological saline solution by using a bioaerosol sampler, and the collection time is 20 min.

[0089] S2. The bioaerosol sample is diluted by 10 times of 0.9% physiological saline solution, and the dilution multiple is recorded.

[0090] S3. 100 μL of the sample is coated on a nutrient agar plate, and placed in a constant temperature incubator at 37℃ for 24 h.

[0091] S4. The cultivable number of E. coli in the sample is calculated in combination with the dilution multiple, and expressed as CFU / mL. 3

[0092]

[0093] Wherein, C 液体浓度 is the cultivable number of microorganisms in the dilution plate count, and 10000 is a fixed value in unit conversion.

[0094] The cultivable number of E. coli bioaerosol exposed to different concentrations of dimethyl sulfide is shown in the figure. Figure 4 The detection results are similar to those of Example 3, and the cultivable number of bioaerosol decreases with the increase of the concentration of VOCs, which also shows that the system described in the present application can truly simulate the interaction between bioaerosol and malodorous waste gas in a landfill, and can automatically adjust the exposure concentration of VOCs, so as to analyze the environmental behavior of bioaerosol exposed to VOCs of different concentrations in different regions.

[0095] Example 5

[0096] The difference between this embodiment and Example 3 is that, in this embodiment S1, the bacterial solution is diluted by 10 times of 0.9% physiological saline solution, and 10 5 ​The bacteria suspension of CFU / mL, Bacillus was selected as the test strain, a three-nozzle Collison bioaerosol generator was selected, methanol was selected as VOC, the sampling flow rate was set to 0.2 μL / min, the VOC gas concentration was set to 0.5 ppm, the interaction exposure experiment was carried out, the liquid impact bioaerosol sampler was used to collect the bioaerosol sample for 20 min, and the ultrafiltration tube was used to concentrate the bioaerosol sample.

[0097] The sample collection and cultivable number calculation include the following steps:

[0098] S1. The bioaerosol sample was collected into 10 mL of 0.9% physiological saline solution by using the impact liquid bioaerosol sampler, and the collection time was 20 min.

[0099] S2. The collected bioaerosol sample was added to the centrifugal ultrafiltration tube for enrichment and concentration, 4000x centrifugation was carried out for 30 min, and the sample was eluted from the ultrafiltration membrane by using 0.9% physiological saline solution.

[0100] S3. The bioaerosol sample was diluted by 10 times by using 0.9% physiological saline solution, and the dilution multiple was recorded.

[0101] S4. 100 μL of the sample was coated on the nutrient agar plate, and placed in a constant temperature incubator at 37°C for 24 h.

[0102] S5. The cultivable number of E. coli in the sample was calculated according to the dilution multiple, and the cultivable number of E. coli in the sample was CFU / mL. 3

[0103]

[0104] Wherein, C 液体浓度 is the cultivable number of microorganisms counted by dilution plating, and 10000 is a fixed value in unit conversion.

[0105] The detection results show that methanol has an effect on the physiological state of Bacillus bioaerosol, and the cultivable number decreases slightly, indicating that the experimental simulation of the coequilibrium exposure of low-concentration methanol to Bacillus bioaerosol is feasible.

[0106] Example 6

[0107] ​The difference between the present embodiment and embodiment 4 is that, in the present embodiment, the VOCs in S3 are set to have an injection flow rate of 10.8, 21.7 and 37.4 μL / min, the calculated VOCs concentration is 40 ppm, 120 ppm and 200 ppm, Pseudomonas aeruginosa is selected as the test strain, dimethyl disulfide and dimethyl trisulfide are selected as the VOCs, the reactor temperature is set to 85℃, and clean air is used to atomize dimethyl disulfide and dimethyl trisulfide gas to generate a bioaerosol in the VOCs co-exposure balance box at a constant flow rate of 5 L / min for 30 min.

[0108] The sample collection and calculation of cultivable number include the following steps:

[0109] S1. The bioaerosol sample is collected into 10 mL of 0.9% physiological saline solution using a bioaerosol sampler, and the collection time is 20 min.

[0110] S2. The bioaerosol sample is diluted by 10 times with 0.9% physiological saline solution, and the dilution factor is recorded.

[0111] S3. 100 μL of the sample is spread on a nutrient agar plate and placed in a 37℃ constant temperature incubator for 22 h.

[0112] S4. The cultivable number of E. coli in the sample is calculated in combination with the dilution factor, and the result is expressed as CFU / mL. 3

[0113]

[0114] wherein C 液体浓度 is the cultivable number of microorganisms in the dilution plate count, and 10000 is a fixed value in unit conversion.

[0115] The detection results show that the mixed sulfide gas dimethyl disulfide and dimethyl trisulfide has an effect on the physiological state of Pseudomonas aeruginosa bioaerosol, and the cultivable number decreases by 2-3 orders of magnitude, indicating that the experimental simulation of co-balance exposure of mixed sulfide gas dimethyl disulfide and dimethyl trisulfide to Pseudomonas aeruginosa bioaerosol is feasible, and can be used to evaluate the effect of real landfill VOCs on bioaerosol and to evaluate the risk of VOCs and bioaerosol in the landfill.

[0116] Example 7

[0117] The difference between the present embodiment and embodiment 6 is that, in the present embodiment, Staphylococcus aureus is selected as the test strain, clean air is used to atomize xylene gas to generate a bioaerosol in the VOCs co-exposure balance box at a constant flow rate of 8 L / min for 30 min, and the VOC gas concentration is 20 ppm. ​

[0118] The sample collection and cultivable number calculation include the following steps:

[0119] S1. Collect the bioaerosol sample into 10 mL of 0.9% physiological saline solution using a bioaerosol sampler, and the collection time is 30 min.

[0120] S2. Dilute the bioaerosol sample by 10 times with 0.9% physiological saline solution, and record the dilution multiple.

[0121] S3. Take 100 μL of the sample and spread it on a nutrient agar plate, and place it in a 37°C constant temperature incubator for 22 h.

[0122] S4. Calculate the cultivable number of E. coli in the sample in combination with the dilution multiple, and express it as CFU / mL. 3

[0123]

[0124] Wherein, C 液体浓度 is the cultivable number of microorganisms in the dilution plate count, and 10000 is a fixed value in unit conversion.

[0125] The detection results show that the xylene gas has an effect on the physiological state of the Staphylococcus aureus bioaerosol, and the cultivable number decreases by 1-2 orders of magnitude, indicating that the experimental simulation of the co-equilibrium exposure of xylene gas to Staphylococcus aureus bioaerosol is feasible, and can be used to evaluate the effect of real printing and dyeing plant wastewater VOCs on bioaerosol and evaluate the risk of real scene VOCs and bioaerosol.

[0126] Example 8

[0127] The difference between this example and Example 7 is that in this example, Staphylococcus aureus and E. coli are selected as test strains, and clean air is used to atomize dimethyl disulfide gas at a constant flow rate of 5 L / min to co-equilibrate with bioaerosol in a VOCs co-exposure equilibrium box for 60 min, and the VOC gas concentration is 20 ppm.

[0128] The sample collection and cultivable number calculation include the following steps:

[0129] S1. Collect the bioaerosol sample into 10 mL of 0.9% physiological saline solution using a bioaerosol sampler, and the collection time is 30 min.

[0130] S2. Dilute the bioaerosol sample by 10 times with 0.9% physiological saline solution, and record the dilution multiple.

[0131] ​S3. Take 100 μL sample to spread on nutrient agar plate, and place in 37℃ constant temperature incubator for 22h.

[0132] S4. Calculate the cultivable number of E. coli in the sample according to the dilution factor, and express it as CFU / m 3

[0133]

[0134] wherein, C 液体浓度 is the cultivable number of microorganism by dilution plating, and 10000 is a fixed value in unit conversion.

[0135] The detection results show that dimethyl disulfide has a weak influence on the physiological state of S. aureus and E. coli bioaerosol, and the cultivable number decreases by 0-1 order of magnitude, indicating that the experimental simulation of co-equilibrium exposure of dimethyl disulfide to S. aureus and E. coli bioaerosol is feasible, and can be used to evaluate the effect of VOCs on bioaerosol in real sewage treatment plants, and to evaluate the risk of VOCs and bioaerosol in sewage treatment plants.

[0136] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods, and all shall be included in the protection scope of the present application.​

Claims

1. A system for the generation, balance and co-exposure of bioaerosols and volatile organic compounds, characterized in that: The system is used to simulate the release of VOCs of different concentrations, different types, and multiple types and the generation of different types of bioaerosols in natural scenes; the system comprises a co-exposure balance box (1), a volatile organic compound gas balance box (2) and a bioaerosol balance box (3) respectively connected to the co-exposure balance box (1) through a pipeline system, and a control device for controlling the operation of the system; The pipeline system includes input paths connected to the volatile organic compound gas balance box (2) and the bioaerosol balance box (3), respectively, and output paths connecting the volatile organic compound gas balance box (2) and the bioaerosol balance box (3) to the co-exposure balance box (1), respectively; an air compressor (9), a flow controller (11), and an air filter (12) are sequentially provided on the input paths; a volatile organic compound generator (4) is also provided in the input path connected to the volatile organic compound gas balance box (2); and a bioaerosol generator (5) is also provided in the input path connected to the bioaerosol balance box (3); The co-exposure balance box (1) is also connected to a bioaerosol collection device (6); the volatile organic compound gas balance box (2) is also connected to a volatile organic compound detector (7); and the bioaerosol balance box (3) is also connected to a bioaerosol particle real-time monitor (8); The input and output paths include branches; the branch of the input path is separated from the air compressor (9), and a flow controller (11) and an air filter (12) are sequentially provided on the branch of the input path; The co-exposure balance box (1), the volatile organic compound gas balance box (2), and the bioaerosol balance box (3) are all provided with a turbulence device (10); The co-exposure balance box (1), the volatile organic compound gas balance box (2), and the bioaerosol balance box (3) are all provided with an exhaust pressure relief device (14); The flow-turbulating device (10) is a fan; the fan blades and the inner wall of each balance box are covered with an anti-stick coating; The bioaerosol generator (5) evenly disperses the microbial suspension that maintains biological activity into clean air to form active bioaerosol, and the generated bioaerosol is introduced into the bioaerosol balance box (3). The bioaerosol generator (5) can adjust the particle size distribution, concentration and population of the active bioaerosol in the system; The vertical side of the bioaerosol balance box (3) is provided with at least three fluid inlets and outlets (13) distributed at equal intervals, which are used as sampling ports. The bioaerosol particle real-time monitor (8) is connected to the bioaerosol balance box (3) through the fluid inlets and outlets (13). When the detection readings of the bioaerosol particle real-time monitor (8) at each fluid inlet and outlet (13) are consistent, it indicates that the bioaerosol balance box (3) is in a balanced state. The volatile organic compound generator (4) can heat and gasify the liquid organic matter to form volatile organic compound gas, and the generated volatile organic compound gas is introduced into the volatile organic compound gas balance box (2). The volatile organic compound generator (4) can adjust the concentration and type of the volatile organic compound gas in the system by changing the amount, type and injection volume of the liquid organic matter; The vertical side of the volatile organic compound gas balance box (2) is provided with at least three fluid inlets and outlets (13) distributed at equal intervals, which are used as sampling ports. The volatile organic compound detector (7) is connected to the volatile organic compound gas balance box (2) through the fluid inlets and outlets (13). When the detection readings of the volatile organic compound detector (7) at each fluid inlet and outlet (13) are consistent, it indicates that the volatile organic compound gas balance box (2) is in a balanced state.

2. The system according to claim 1, characterized in that The pipeline system is also provided with an air valve for controlling the inflow and outflow of aerosol or gas.

3. The system according to claim 1, characterized in that The exhaust pressure relief device (14) is an exhaust pressure relief valve.

4. The method for using the system according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Adding a solution of volatile organic compounds to be tested into the injection needle of the volatile organic compound generator (4), using the pipeline system to make the volatile organic compound generator (4) generate volatile organic compounds and enter the volatile organic compound gas balance box (2), and after the box is filled with volatile organic compounds, the volatile organic compound generator (4) is turned off, and the volatile organic compounds in the box are allowed to enter dynamic equilibrium; S2. Place the suspension of the microorganism to be tested in the liquid bottle of the bioaerosol generator (5), use the pipeline system to make the bioaerosol generator (5) generate microbial aerosol and enter the bioaerosol balance box (3), and turn off the bioaerosol generator (5) after the box is filled with microbial aerosol, and wait for the microbial aerosol in the box to achieve dynamic equilibrium; S3. The dynamically balanced volatile organic compounds and microbial aerosols are simultaneously introduced into the co-exposure balance box (1) through the output of the pipeline system for dynamic balance. The microbial aerosol samples are collected and enriched using the bioaerosol collection device (6). The enriched microorganisms are subjected to gradient dilution and plate culture. The culturable number of microorganisms in the sample is calculated based on the dilution multiple, and the changes in the culturable number of microorganisms are observed to observe the effects of volatile organic compounds on microbial aerosols. The calculation formula for the culturable number is: ； Among them, C 液体浓度 The culturable number of microorganisms counted on a dilution plate.

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