RU2602178C2 - Method of decontamination of soil, contaminated with anthrax - Google Patents

Abstract

FIELD: veterinary science.

SUBSTANCE: invention relates to veterinary science, namely to biological systems for decontamination of soil, contaminated with anthrax. Method of decontamination of soil, contaminated with anthrax, consists in the fact, that before installation of film over contaminated area, borders of this area and soil structure are determined by means of application, for example, of ground penetrating radar. Then this part is compacted, if necessary, with help of vibration actions, for example, by means of plate compactors or roller. Then tightness of installed film is checked with help of, for example, compressor plant, equipped with measuring instruments, which are connected with air-filled under-film space through valves, tightly installed in holes of film. Then air space and soil area under film are heated or cooled to temperature of +8…+10 °C. Then liquefied gas is supplied into open vessels, equipped with adjustable fire-explosion-proof heating device. After evaporation of liquefied gas, sorption of soil with its layers and exposure neutralization of gases in under-film area is made in emergency cases during decontamination, as well as at the end of this process by compressor, equipped with neutralization chamber and adsorbent container.

EFFECT: proposed method of soil decontamination provides effective and environmentally friendly method for eliminating biological contamination.

3 cl, 1 dwg

Description

The invention relates to veterinary medicine, in particular to biological systems for disinfecting the soil when it is contaminated with the causative agent of anthrax.

A known method of disinfecting soil, mainly contaminated with the causative agent of anthrax, involves the introduction into the soil of actinomycetes antagonists of the genus "Cinereas" (copyright certificate No. 528917, IPC A01N 7/04). The method makes it possible to use the natural processes of antagonism that occur in the microflora of the soil, for its disinfection.

The disadvantage of this method is its low efficiency, because a positive result is achieved only when disinfecting the surface layer of soil contaminated with anthrax. In addition, disinfection in this way requires a long time and creation of favorable conditions for soil actinomycetes antagonists.

There is a known method of disinfecting territories of old cattle cemeteries, in which these territories are watered with an aqueous solution of “SaBiDez” (article “Disinfection of territories of old cattle cemeteries”, authors: VV Pryanichnikova, I.Kh. Bikbulatov, EI Bakhonina. Magazine “Safety life activity ”No. 11, 2013, p. 16-20).

This method can be used only at positive temperatures of the soil and the environment and takes a long time (up to a year). The authors do not provide information about the possibility of using the developed method for the disinfection of soil contaminated with anthrax.

There is also a method of disinfecting the soil by exposing the soil to electromagnetic fields of ultrahigh frequency with heating the soil to temperatures up to 64-70 ° C at a rate of 0.04-0.5 ° C / s, followed by thermostating without supplying a coolant for at least 180 seconds ( patent RU No. 2125355, IPC АВВ 47/00). The cooling rate of the soil should be no more than 0.05 ° C / s. The use of electromagnetic fields can reduce the time for tillage.

The disadvantages of this method include its inefficiency in the deep soil foci of anthrax and the lack of laboratory data regarding the effectiveness of its application to the causative agent of anthrax.

The closest technical solution to the claimed object is a method of disinfecting the soil (copyright certificate No. 376074, IPC A01N 7/04), which consists in stretching a film over the infected area parallel to the surface of the earth, the edges of which are dug with earth, and open vessels are placed under the film, into which liquefied gas is poured, for example a gas mixture of ethylene oxide with methyl bromide (OKEBM). In order to increase the disinfection efficiency, this method proposes to dig open pits in the ground before installing the covering film.

The disadvantages of this method include:

- possible unreliability of the biological hazard of the site subjected to disinfection, because it does not provide for an additional study of the contaminated site in order to clarify its boundaries;

- lack of effectiveness of the disinfection process, because the process itself depends on external conditions (temperature, humidity and soil structure);

- uncontrolled tightness of the structure (condition of the film and its fixing in the soil), which can lead to an emergency (leak or release of toxic gases into the atmosphere);

- lack of monitoring of the disinfection process, which may disrupt the safe disinfection process itself;

- environmental pollution with toxic gases at the end of the disinfection process, as after removing the film there is a natural ventilation of the site.

The claimed method allows to increase the efficiency of the disinfection of biological objects (soil foci) when they are contaminated with anthrax and exclude environmental pollution by neutralizing the toxicity of the mixture of biocidal gases (a mixture of ethylene oxide with methyl bromide - OKEBM).

The task is achieved by the fact that at the beginning of the soil disinfection process, the boundaries of the anthrax contaminated area are examined and clarified by the method of deep radar sounding of the underlying surface, in order to clarify the size and location of the remains of animals and signs of a potential source of biological hazard in the form of bioorganic remains and change the integrity of structures the soil. A geophysical device, such as a georadar, can be used to probe the soil.

To exclude the spread of gas into soil voids (the presence of more than 5 earth passages from migrating earthworms, residues of root vegetation, etc. on a section with an area of about 25 cm ^{2 of the} underlying surface), the underlying surface is compacted using various vibration effects, for example, vibrating plates or rollers . Then, temperature sensors and open vessels are placed on the contaminated site, and pits are drilled.

In the claimed method of disinfection, as in the prototype, the infected area is covered with a film, drilled pits, use a mixture of OKEBM. In contrast to the prototype, in the inventive method, before starting work, the boundaries of the disinfection site are clarified, the tightness of the structure and the course of the disinfection process are checked and controlled, and conditions (temperature, tightness, soil density) are created that provide the most efficient course of the soil disinfection process and ensure safety from environmental pollution by toxic gases.

The proposed method of soil disinfection is illustrated in the drawing, where in FIG. 1 schematically shows the process of its implementation.

The application of the method of soil disinfection is as follows: before starting work, fencing and cleaning of the territory to be disinfected from shrubs, old buildings, etc., then establish the boundaries of the disinfection site and the soil structure using GPR, and if the site has a large area, then it is divided into separate sections, for example, with an area of not more than 200 m ² each.

After the boundaries of the site are determined, produce compaction of this site, for example with a plate or rollers (if there are earth passages or voids in the soil). Then, small grooves up to 40 cm deep are dug around the perimeter of the site. Alignment of open vessels 1 is performed over the entire area of the site (one vessel per 20-25 m2 ^of area). A pit 2 with a diameter of 15 cm is made near each vessel in the soil. The depth of pit 2 is determined by the estimated depth of disinfection. To improve the process of gas evaporation, the vessels 1 are equipped with an adjustable fire-explosion-proof heating device, which can be performed by any of the known methods. Then, temperature sensors 3 are placed on the plot. Next, the plot is covered with a gas-tight heat-resistant film 4 (disposable or reusable) so that there is at least 15-20 cm of air space above the soil surface, the edges of the film are lowered into grooves 5 formed along the boundaries of the plot 5 (at least 40 cm deep) into which the edges of the film are lowered and dug up with earth. In the film 4, holes 6 are preliminarily made with valves for connecting special equipment (hoses and wires). Then, using the compressor 7, the tightness and integrity of the structure are checked (air is removed from the sub-film space, i.e., a vacuum is created). Compressor 7 is equipped with a pressure gauge for monitoring pressure and is connected to the sub-film airspace through a sealed valve system of air passage hoses. The degree of process discharge is monitored using gauge devices of compressor 7. If there is no vacuum, then there is an air leak, i.e. the tightness is broken, which is eliminated before the start of the disinfection process with a mixture of biocidal gases.

In case of inconsistency of weather environmental conditions with the technical conditions of the disinfection process with a mixture of biocidal gases (soil temperature within 8 ... 10 ° C, humidity within 33%), the soil section to be disinfected is cooled or heated. For this, the sub-film space is filled with warm or cooling air flows using a compressor unit 8 equipped with an air conditioning system (Instructions for gas disinfection of anthrax cattle cemeteries. 1981, Moscow, Kolos). If the temperature is below the specified limit (8 ... 10 ° C), then the duration of the process of sorption of a mixture of biocidal gases by soil layers increases. If the temperature is above the specified limit, then there is a possibility of leakage of the gas mixture of biocidal gases (film rupture and leakage at the edges of the section are possible). At the indicated temperature limits, the optimal process of the transition of the mixture from liquid to gaseous state occurs. The pressure control of the air space under the film is carried out using the pressure gauge of the compressor unit 7, and in the case of excessive pressure, the air mixture is sucked and neutralized (keys 11 and 12). Alternatively, a pressure relief valve can be installed in the hose of the bore 6 to control the pressure. Infrared heaters can be used to maintain the temperature level for a long time. The air temperature below the film is monitored using temperature sensors 3.

OKEBM liquid gas (for example, a gas mixture: 1 part of ethylene oxide and 2.5 parts of methyl bromide) is supplied to the formed closed system from a cylinder 9 through a distributor 10, through hoses and special valves mounted in the holes 6 of the film coating 10 (for example, a tee) is distributed in the vessels 1 installed under the film 4.

Depending on the average temperature under the coating and the total surface area of the vessels, the evaporation of a given dose of the liquid phase of the preparation lasts from 6 to 24 hours (the main part of the biocidal gas mixture is adsorbed by the soil layers up to 12 hours).

Slowly evaporating gas fills the enclosed airspace and penetrates the soil through pits. The gas has an extremely high penetrating ability, as it evaporates, it gradually penetrates the soil to a depth of 200 cm, is evenly sorbed by all soil layers of the disinfected area and under certain conditions that are provided in the claimed object (concentration, exposure, temperature and soil moisture), disinfection effect.

The magnitude of the regimes that ensure disinfection of the soil in horizons with a depth of 0 to 200 cm is directly dependent on the required depth of disinfection. So, when using OKEBM gas at the rate of 0.5 kg and 1 kg per 1 sq. M. and exposure, respectively, for 10 and 5 days, disinfection of soil seeded with bac spores. Anthracis, achieved at a depth of 0 to 30 cm; at a flow rate of 2 kg and an exposure of 10 days - at a depth of 100 to 125 cm. Reliable disinfection of the soil at a depth of 200 cm is achieved after 10 days at a flow rate of 3 kg of OKEBM gas per 1 sq. m. area. The duration of the disinfection exposure according to the Instructions for gas disinfection of anthrax cattle burial grounds, 1981 Moscow, Kolos, should be no more than 30 days.

After completion of the disinfection exposure (or in case of emergency), the process of forced neutralization of a toxic mixture of biocidal gases (ethylene oxide with methyl bromide) in the underfilm space is carried out by means of mobile neutralizers (pos. 11 and 12) installed on the vehicle or in portable neutralizers, depending on the volume of the gas mixture and the area of the sites for disinfection.

The neutralization of a toxic gas mixture occurs as follows. Through a sealed system of air ducts, the exhaust gas mixture is aspirated by the compressor 7 and sequentially fed into the neutralization chamber 11, in which, with the addition of special chemical compounds, for example, ammonia solution, the process of rapid decomposition of the exhaust gas mixture occurs, i.e. it is neutralized. Then, through a sealed system of air ducts, the mixture of treated gases enters a container 12 containing an adsorbent. In the container 12 due to trapping and adsorption, the final stage of neutralizing the toxic effect of the mixture of biocidal gases occurs.

The cost-effectiveness of the method is to minimize costs and reduce the time for disinfecting the soil in comparison with the prototype. A positive effect of the proposed method is also the elimination of environmental pollution by neutralizing the toxicity of a mixture of biocidal gases (a mixture of ethylene oxide with methyl bromide in various proportions).

The invention is industrially applicable because it can be repeatedly implemented to achieve the specified technical result, and can also be used to disinfect soil contaminated with other less stable pathogens.

Claims (3)

1. The method of disinfecting soil contaminated with anthrax, including drilling pits, arranging open vessels, coating the infected area with a film, the edges of which are dug up with soil, characterized in that before installing the film over the contaminated area, the boundaries of the area and soil structure are determined by using, for example, GPR then, if necessary, compact this area with the help of vibration effects, for example with a vibrating plate or roller, then check the tightness of the installed film with , for example, a compressor unit equipped with measuring instruments that are connected to the air subfilm space through valves hermetically placed in the holes of the film, and then warm or cool the air space and the soil under the film to a temperature of + 8 ... + 10 ° C and only after this is served in open vessels liquefied gas. 2. The method according to p. 1, characterized in that after evaporation of the liquefied gas, its sorption by soil layers and exposure, or in urgent cases, the gases are neutralized from the sub-film air space both during the disinfection process and upon completion of this process using a compressor equipped with a neutralization chamber and an adsorbent container. 3. The method according to p. 1, characterized in that the open vessels are equipped with adjustable fire and explosion-proof heating devices.

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