Method for predicting disinfectant dosage of aerosol air

Abstract

The invention discloses a method for predicting the air disinfectant dosage of aerosol. The method comprises the following steps: S1, sending biological aerosol into a disinfection chamber; s2, disinfecting the interior of the disinfection chamber; s3, in the disinfection process, collecting the naturally settled biological aerosol; s4, culturing the collected biological aerosol, counting colony formation units, and calculating the concentration of the biological aerosol to obtain the disinfection efficiency; s5, the conditions of the disinfection process and the disinfection efficiency are substituted into a disinfection mechanical formula for fitting to obtain all parameter values, and finally a disinfection dynamic formula under certain disinfectant concentration and disinfection action time is obtained and used for predicting the dosage of the used disinfectant when certain air disinfection efficiency is achieved. The method can standardize the use of an air disinfection mode and discuss the optimal use amount of a disinfectant, and can safely and efficiently remove pathogenic microorganisms in air.

Description

Technical Field

[0001] The invention relates to the field of air disinfection, and more particularly to a method for predicting aerosol air disinfection dosage. Background Art

[0002] Physical disinfection and chemical disinfection are the more commonly used disinfection methods. In this disinfection process, commonly used chemical disinfectants include peroxide disinfectants and chlorine-containing disinfectants, which are widely used due to their high disinfection efficiency and simple operation. However, excessive use of disinfectants will lead to disinfectant residues and produce disinfection by-products, which will cause ecological and health hazards. Therefore, it is necessary to standardize the use of air disinfection methods and explore the optimal dosage of disinfectants to safely and efficiently remove airborne pathogens.

[0003] At present, the research on predicting the disinfection dosage of disinfectants under a certain disinfection efficiency is mainly focused on water media, such as "Research on the kinetics of ultraviolet disinfection reaction under different biological loads" published by Gou Shuting, Ning Nan, Zhang Jiku, Yang Shan, etc. (Energy Conservation Basic Science, 2018, No. 2). Another example is "Ultraviolet disinfection kinetic model and influencing factors" published by Feng Haining, Xu Dongyu, Dong Yilin, Zhang Lin, Wang Pengfei, Ren Zhijun, etc. (Water Purification Technology, 2018, No. 2).

[0004] 2020,39(6):83-89).

[0005] However, there is no research on predicting the disinfection dosage of disinfectants in the air medium at a certain disinfection efficiency. Summary of the invention

[0006] In view of the defects existing in the prior art, the purpose of the present invention is to provide a method for predicting the dosage of aerosol air disinfection, which can standardize the use of air disinfection methods and explore the optimal dosage of disinfectants, and can also safely and efficiently remove airborne pathogenic microorganisms.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] A method for predicting aerosol air disinfection dosage comprises the following steps:

[0009] S1. Send the bioaerosol into the disinfection chamber;

[0010] S2, disinfecting the disinfection chamber;

[0011] S3. During the disinfection process, collecting the naturally settled bioaerosol;

[0012] S4. Cultivating the collected bioaerosol, counting colony forming units, calculating the concentration of the bioaerosol, and obtaining the disinfection efficiency;

[0013] S5. Substitute the conditions of the disinfection process and the disinfection efficiency into the disinfection mechanics formula for fitting to obtain the values ​​of various parameters, and finally obtain the disinfection kinetics formula under a certain disinfectant concentration and disinfection action time, which is used to predict the disinfectant dosage used to achieve a certain air disinfection efficiency.

[0014] Preferably, in step S1, the disinfection chamber is a glass-enclosed aerosol disinfection chamber of 0.3m×0.3m×0.3m.

[0015] Preferably, the bioaerosol is delivered to the disinfection chamber through an atomizer for 75 seconds and then left to stand for 30 seconds.

[0016] Preferably, in step S2, the disinfectant is atomized and sprayed into the disinfection chamber by the atomizer for disinfection.

[0017] Preferably, the disinfectant dose is calculated as follows:

[0018]

[0019] Where C is the concentration of the disinfectant; T is the time of spraying the disinfectant; u is the flow rate, which is equal to 0.2 mL min -1 ; V is the chamber volume of the disinfection chamber.

[0020] Preferably, in step S2, disinfection is performed by irradiating with an ultraviolet lamp in the disinfection chamber.

[0021] Preferably, the UV dose of the UV lamp is calculated as follows:

[0022] UV dose=UV intensity*T

[0023] Where UV intensity is the intensity of ultraviolet radiation; T is the ultraviolet radiation time.

[0024] Preferably, the step S3 specifically includes:

[0025] The disinfection chamber is disinfected for 5, 6, 8, 10 or 15 minutes, and during the disinfection process, the naturally settled bioaerosol is collected for 5 minutes.

[0026] Preferably, the step S4 specifically includes:

[0027] The bioaerosol is collected on a nutrient agar medium plate, and after culturing at 37° C. for 48 hours, the colony forming units are counted to calculate the concentration of the bioaerosol;

[0028] Three parallel experiments are set up in the process of step S1 to step S4, and the disinfectant rate is calculated as follows:

[0029]

[0030] Wherein, N0 is the colony forming unit before disinfection; N is the colony forming unit after disinfection.

[0031] Preferably, the fitting process in step S5 is as follows:

[0032] The Chick-Watson model is used to express the kinetics of disinfection by disinfectants, and is also applicable to ultraviolet radiation disinfection. Its first-order kinetic expression is:

[0033]

[0034] The integral of the first-order kinetic expression is:

[0035]

[0036] In the formula, N0 is the colony forming unit before disinfection; N is the colony forming unit after disinfection; C is the concentration of the disinfectant; K is the coefficient of the lethal potential of disinfection; N is the dilution factor, which is 1; t is the exposure time of the disinfectant;

[0037] In order to reflect the initial reduction when the disinfectant first comes into contact with the bioaerosol, the coefficient A needs to be introduced. At this time, the Chick-Watson model expression is:

[0038]

[0039] When n=1, the Chick-Watson model becomes:

[0040]

[0041] During ultraviolet radiation disinfection, the Chick-Watson model is modified by replacing the concentration C of the disinfectant with the intensity I of ultraviolet radiation. At this time, the Chick-Watson model expression is:

[0042]

[0043] The method for predicting the dosage of aerosol air disinfection provided by the present invention uses air as the disinfection medium, fills the gap in the air disinfection prediction model, and can predict the disinfection efficiency of various disinfection methods, including various chemical disinfectants and ultraviolet disinfection, and can also give different disinfection dosages for various microorganisms, thereby providing protection for the disinfecting of airborne pathogenic microorganisms and air health and safety. At the same time, by comparing the disinfectant dosage predicted by different disinfectant concentrations and disinfection times, the minimum dosage used can be given to reduce the chemical and ecological hazards of the disinfectant. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic flow chart of a method for predicting aerosol air disinfection dosage of the present invention;

[0045] Figure 2 Schematic diagram of the disinfection system in the method for predicting aerosol air disinfection dosage of the present invention, (a) is a chemical disinfection system, (b) is a physical disinfection system;

[0046] Figure 3 It is a schematic diagram of the disinfecting kinetic fitting curve of sodium hypochlorite disinfecting air bacteria for 15 minutes in Example 1 of the method for predicting the aerosol air disinfection dosage of the present invention;

[0047] Figure 4 It is a schematic diagram of the disinfecting kinetic fitting curve of hydrogen peroxide disinfecting air bacteria for 15 minutes in Example 2 of the method for predicting the aerosol air disinfection dosage of the present invention;

[0048] Figure 5 It is a schematic diagram of the disinfecting kinetic fitting curve of ultraviolet disinfection of air bacteria for 15 minutes in Example 3 of the method for predicting aerosol air disinfection dosage of the present invention. DETAILED DESCRIPTION

[0049] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0050] Combination Figure 1 As shown, a method for predicting aerosol air disinfection dosage provided by the present invention can predict the disinfection dosage required when chemical disinfection methods and physical disinfection methods reach a certain air efficiency, comprising the following steps:

[0051] S1. Send the bioaerosol into the disinfection chamber;

[0052] S2. Disinfect the disinfection room;

[0053] S3. Collect naturally settled bioaerosols during the disinfection process;

[0054] S4. Cultivate the collected bioaerosol, count the colony forming units, calculate the concentration of the bioaerosol, and obtain the disinfection efficiency;

[0055] S5. Substitute the conditions and efficiency of the disinfection process into the disinfection mechanics formula to fit the values ​​of each parameter, and finally obtain the disinfection kinetics formula under a certain disinfectant concentration and disinfection action time, which is used to predict the disinfectant dosage used to achieve a certain air disinfection efficiency.

[0056] Combination Figure 2 As shown, the disinfection chamber 1 is a glass-enclosed aerosol disinfection chamber of 0.3m×0.3m×0.3m. The atomized bioaerosol and disinfectant generated by the atomizer 2 are uniformly sprayed into the disinfection chamber 1 through the holes on the side wall of the disinfection chamber 1.

[0057] Ultraviolet lamp 3 was used as the UV light source, and all experimental operations were performed in a closed environment to avoid light.

[0058] In order to average the UV irradiation intensity, a symmetrical 9-point grid measurement was performed in the disinfection chamber 1 cavity. The irradiance at three equidistant vertical levels of the aerosol chamber was measured. The UV intensity tester was used to scan and measure 27 points covering the entire interior space. The measured UV irradiance was averaged and used for the calculation of the UV inactivation rate constant.

[0059] The bioaerosol is sent to the disinfection chamber 1 through the atomizer 2 for 75 seconds, and then left to stand for 30 seconds to allow the microorganisms to be evenly dispersed. The disinfectant is then atomized and sprayed into the disinfection chamber 1 through the atomizer 2 for disinfection. For disinfection with disinfectants, the amount of disinfectant is controlled according to the initial concentration of the disinfectant and the spraying time. The disinfectant dose is calculated as follows:

[0060]

[0061] Where C is the concentration of the disinfectant; T is the time of spraying the disinfectant; u is the flow rate, which is equal to 0.2 mL min -1 ; V is the chamber volume of the disinfection chamber.

[0062] For disinfection by UV lamp 3, the UV radiation dose is controlled by controlling the UV irradiation time. The UV dose of the UV lamp is calculated as follows:

[0063] UV dose=UV intensity*T

[0064] Where UV intensity is the intensity of ultraviolet radiation; T is the ultraviolet radiation time.

[0065] Afterwards, disinfection was performed in the disinfection chamber 1 for 5, 6, 8, 10 or 15 minutes. During the disinfection time, the naturally settled bioaerosols were collected for 5 minutes, the bioaerosols were collected on nutrient agar culture plates, and after culturing at 37°C for 48 hours, the colony forming units (CFU) were counted and the concentration of the bioaerosols was calculated;

[0066] Three parallel experiments were set up in the process from step S1 to step S4, and the disinfectant rate was calculated as follows:

[0067]

[0068] Wherein, N0 is the colony forming unit before disinfection; N is the colony forming unit after disinfection.

[0069] The fitting process in step S5 is as follows:

[0070] The Chick-Watson model is used to express the kinetics of disinfection by disinfectants, and is also applicable to ultraviolet radiation disinfection. Its first-order kinetic expression is:

[0071]

[0072] The integral of the first-order kinetic expression is:

[0073]

[0074] In the formula, N0 is the colony forming unit before disinfection; N is the colony forming unit after disinfection; C is the concentration of the disinfectant; K is the coefficient of the lethal potential of disinfection; N is the dilution factor, which is 1; t is the exposure time of the disinfectant;

[0075] In order to reflect the initial reduction when the disinfectant first comes into contact with the bioaerosol, the coefficient A needs to be introduced. At this time, the Chick-Watson model expression is:

[0076]

[0077] When n=1, the Chick-Watson model becomes:

[0078]

[0079] During ultraviolet radiation disinfection, the Chick-Watson model is modified by replacing the concentration C of the disinfectant with the intensity I of ultraviolet radiation. At this time, the Chick-Watson model expression is:

[0080]

[0081] This formula is a disinfection kinetics formula under a certain disinfectant concentration and disinfection action time. This formula can be used to predict the disinfectant dosage used to achieve a certain air disinfection efficiency.

[0082] Example 1

[0083] In this embodiment 1, sodium hypochlorite disinfectant is used, the disinfection time is 15 minutes, and the disinfectant concentration is 3%, 1.5%, 0.75%, and 0.375%. The predicted kinetic curve and disinfectant dosage are as follows: Figure 3 As shown, the bacteria used are mixed bacteria of air culturable bacteria.

[0084] By using the method for predicting the aerosol air disinfection dosage of this embodiment 1, it is predicted that the disinfectant dosage used for sodium hypochlorite disinfection to achieve a disinfection efficiency of 90%, 99% and 99.9% is as shown in the following table:

[0085]

[0086] Example 2

[0087] In Example 2, hydrogen peroxide disinfectant was used, the disinfection time was 15 minutes, and the disinfectant concentrations were 3%, 1.5%, and 0.75%. The predicted kinetic curves and disinfectant dosages were as follows: Figure 4 shown.

[0088] By using the method for predicting the aerosol air disinfection dosage of this embodiment 2, it is predicted that the disinfectant dosage used for hydrogen peroxide disinfection to achieve a disinfection efficiency of 90%, 99% and 99.9% is as shown in the following table:

[0089]

[0090] Example 3

[0091] In Example 3, ultraviolet disinfection was used for 15 minutes, and the ultraviolet irradiation intensity was 78.11 μw·cm-2. The predicted kinetic curve and disinfectant dosage were as follows: Figure 5 shown.

[0092] By using the method for predicting the aerosol air disinfection dosage of this embodiment 3, it is predicted that the disinfectant dosage used for ultraviolet disinfection to achieve a disinfection efficiency of 90%, 99% and 99.9% is as shown in the following table:

[0093]

[0094] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A method for predicting aerosol air disinfection dosage, characterized in that: The following steps are involved: S1. Send the bioaerosol into the disinfection chamber; S2, disinfecting the disinfection chamber; S3. During the disinfection process, collecting the naturally settled bioaerosol; S4. Cultivating the collected bioaerosol, counting colony forming units, calculating the concentration of the bioaerosol, and obtaining the disinfection efficiency; S5. Substitute the conditions of the disinfection process and the disinfection efficiency into the disinfection mechanics formula for fitting to obtain the values ​​of various parameters, and finally obtain the disinfection kinetics formula under a certain disinfectant concentration and disinfection action time, which is used to predict the disinfectant dosage used to achieve a certain air disinfection efficiency.

2. The method for predicting aerosol air disinfection dosage according to claim 1, characterized in that: In step S1, the disinfection chamber is a glass-enclosed aerosol disinfection chamber of 0.3m×0.3m×0.3m.

3. The method for predicting aerosol air disinfection dosage according to claim 2, characterized in that: The bioaerosol is delivered to the disinfection chamber through an atomizer for 75 seconds and then left to stand for 30 seconds.

4. The method for predicting aerosol air disinfection dosage according to claim 3, characterized in that: In the step S2, the disinfectant is atomized and sprayed into the disinfection chamber by the atomizer for disinfection.

5. The method for predicting aerosol air disinfection dosage according to claim 4, characterized in that: The disinfectant dose is calculated as follows: Where C is the concentration of the disinfectant; t is the time of spraying the disinfectant; u is the flow rate, which is equal to 0.2 mL min -1 ; V is the chamber volume of the disinfection chamber.

6. The method for predicting aerosol air disinfection dosage according to claim 3, characterized in that: In the step S2, disinfection is performed by irradiating with ultraviolet light in the disinfection chamber.

7. The method for predicting aerosol air disinfection dosage according to claim 6, characterized in that: The UV dose of the UV lamp is calculated as follows: UV dose=UV intensity*T Where UV intensity is the intensity of ultraviolet radiation; T is the ultraviolet radiation time.

8. The method for predicting aerosol air disinfection dosage according to claim 5 or 7, characterized in that: The step S3 specifically includes: The disinfection chamber is disinfected for 5, 6, 8, 10 or 15 minutes, and during the disinfection process, the naturally settled bioaerosol is collected for 5 minutes.

9. The method for predicting aerosol air disinfection dosage according to claim 8, characterized in that: The step S4 specifically includes: The bioaerosol is collected on a nutrient agar medium plate, and after culturing at 37° C. for 48 hours, the colony forming units are counted to calculate the concentration of the bioaerosol; Three parallel experiments are set up in the process of step S1 to step S4, and the disinfectant rate is calculated as follows: Wherein, N0 is the colony forming unit before disinfection; N is the colony forming unit after disinfection.

10. The method for predicting aerosol air disinfection dosage according to claim 9, characterized in that: The fitting process in step S5 is as follows: The Chick-Watson model is used to express the kinetics of disinfection by disinfectants, and is also applicable to ultraviolet radiation disinfection. Its first-order kinetic expression is: The integral of the first-order kinetic expression is: In the formula, N0 is the colony forming unit before disinfection; N is the colony forming unit after disinfection; C is the concentration of the disinfectant; K is the coefficient of the lethal potential of disinfection; N is the dilution factor, which is 1; t is the exposure time of the disinfectant; In order to reflect the initial reduction when the disinfectant first comes into contact with the bioaerosol, the coefficient A needs to be introduced. At this time, the Chick-Watson model expression is: When n=1, the Chick-Watson model becomes: During ultraviolet radiation disinfection, the Chick-Watson model is modified by replacing the concentration C of the disinfectant with the intensity I of ultraviolet radiation. At this time, the Chick-Watson model expression is:

Images