FR3115463A1 - METHOD AND INSTALLATION FOR DISINFECTING SURROUNDING AIR - Google Patents

Abstract

To disinfect surrounding air (1a), (a) capturing from the surrounding air (1a) an airflow (F1) that may be contaminated by microorganisms, (b) subjecting this airflow ( F1) to a disinfection treatment by bringing this air flow (F1) into contact with a biocidal liquid (203) containing at least one biocidal agent, so as to obtain an intermediate air flow (F2) at least partially disinfected, then (c) this intermediate air flow (F2) is subjected to washing by bringing this intermediate air flow (F2) into contact with a washing liquid (213), and (d) surrounding air (1a) all or part of said disinfected and washed air flow (F3). Figure 1

Description

PROCESS AND FACILITY FOR DISINFECTING SURROUNDING AIR

This invention is the result of a contract signed by the Ministry of Defence, which has certain rights over it.

The present invention relates to the field of disinfection of surrounding air which may be contaminated by microorganisms, said surrounding air possibly being, for example, air in a closed or closed space or possibly being free air outdoors, and the disinfection being able to be carried out without danger for a living being, and in particular a human being breathing said surrounding air.

Prior art

To disinfect surrounding air which may be contaminated by microorganisms, it is known to treat this surrounding air by spraying it with biocidal products, such as for example hydrogen peroxide or ozone and/or by treating the surrounding air by ozonization of the air by means of corona discharge and/or by UV irradiation. A disadvantage of these methods however lies in the fact that these biocidal products are toxic for living beings, in particular for human beings, present in the surrounding air.

It is also known to disinfect surrounding air by UV irradiation so as to have an action of destroying microorganisms by UV radiation, or even by using the plasma technique. A disadvantage of these methods lies in the fact that they can be accompanied by physico-chemical reactions in the surrounding air resulting in the uncontrolled generation in the surrounding air of by-products, which can be toxic for a living being. , and in particular for a human being present in the surrounding air. In addition, UV radiation can also be dangerous for a living being, and in particular for a human being present in the surrounding air.

It is also known to date, to disinfect the air inside a closed space, as well as the surfaces present in a closed space, to implement a disinfection process by air, described for example in European patent application EP 0 774 263 and comprising two successive main phases: a first phase of disinfection of the enclosed space followed by a second phase of reconditioning of the enclosed space.

The confined space can be any type of enclosed space susceptible to contamination.

During the first disinfection phase, at least one biocidal agent in the gaseous state is dispersed in said enclosed space , then this biocidal agent is allowed to act for a sufficient period of time. Said biocidal agent is selected according to the type of pathogenic microorganisms to be destroyed or neutralized during disinfection. The biocidal agent can thus be, for example, a bactericide and/or fungicide and/or sporicide and/or virucide, etc.

An example of a biocidal agent commonly used for the disinfection of closed spaces is more particularly hydrogen peroxide in the vapor state.

By way of non-limiting example, in the processes known to date, hydrogen peroxide in the vapor state is used, obtained by evaporation of an aqueous solution of hydrogen peroxide at a concentration of 35% at 50% by weight of hydrogen peroxide.

During the second phase of reconditioning the enclosed space, a gas stream, and generally an air stream, containing a quantity of biocidal agent is captured in the enclosed space, said gas stream is subjected to a treatment allowing to reduce the concentration of the biocidal agent present in said gas stream and all or part of the treated gas stream is dispersed in the enclosed space, said reconditioning phase of the enclosed space being carried out until the concentration of biocidal agent in the enclosed space is low enough, and more particularly until the concentration of biocidal agent in the enclosed space is low enough to no longer be toxic to humans. Typically, it is sought to obtain, at the end of the reconditioning phase of the confined space, a concentration of biocidal agent in the confined space which is less than 1ppm.

Biocidal agents, and in particular hydrogen peroxide in the vapor state, are toxic products for humans. It follows that the aforementioned process must necessarily be carried out without human presence in the enclosed space.

There is thus today a need to be able to carry out a disinfection of surrounding air which may be contaminated by microorganisms, which is without danger for a living being, and in particular a human being breathing this surrounding air, said surrounding air being able indifferently be air in an enclosed or enclosed space or may be open air outdoors.

Presentation of the invention

The main objective of the present invention is thus to propose a new technical solution for disinfection of surrounding air which may be contaminated by pathogenic microorganisms, said disinfection being advantageously able to be implemented in the presence of living being(s), and in particular in the presence of human being(s), without danger for the living being(s) present in this surrounding air.

The first object of the invention is thus a process for disinfection of surrounding air, during which (a) an air flow which may be contaminated by microorganisms is captured in the surrounding air (1a), (b) subjects this flow of air to a disinfection treatment by bringing this flow of air (F1) into contact with a biocidal liquid containing at least one biocidal agent, so as to obtain an intermediate flow of air (F2) at least in disinfected part, then (c) this intermediate air flow (F2) is subjected to washing by bringing this intermediate air flow (F2) into contact with a washing liquid (213), so as to obtain a flow of disinfected and washed air (F3) and (d) all or part of said disinfected and washed air flow (F3) is rejected into the surrounding air (1a).

When the intermediate air flow from the disinfection step (b) contains biocidal agent(s) sampled in contact with the biocidal liquid, the washing step (c) makes it possible to capture at least part of the biocidal agent(s) present in the intermediate air flow and to obtain a disinfected and washed air flow in which the concentration of biocidal agent(s) is lower than that in said intermediate air flow, and preferably is nothing.

In addition, most of the time the chemical composition of the surrounding air is not controlled, so that the surrounding air can also contain toxic compounds, such as in particular, and not exhaustively, alcoholic compounds, aldehydes , ketones, hydrocarbons, BTEX (Benzene, Toluene, Ethylbenzene and Xylenes), Terpenes, chlorinated compounds or derivatives of these various toxic compounds. When the intermediate air flow from the disinfection step (b) contains such toxic compounds or their derivatives, the washing step (c) can also advantageously make it possible to capture at least some of these toxic compounds or their derivatives. derivatives present in the intermediate air flow.

More particularly, the method of the invention may comprise the following additional and optional characteristics, taken in isolation, or in combination with each other:

• The biocidal liquid is obtained by adding at least one biocidal agent to a liquid solution.
• The concentration of said at least one biocidal agent in the biocidal liquid is between 1% and 20% by weight, and preferably between 5% and 10% by weight.
• The biocidal agent is hydrogen peroxide.
• The biocidal liquid is obtained by treating a liquid so as to confer on said liquid biocidal properties or to reinforce the biocidal properties of said liquid.
• The biocidal liquid is obtained by irradiation of a liquid and in particular by UV irradiation.
• The disinfected and washed air flow is filtered, before rejecting it into the surrounding air in order to lower the concentration of at least biocide in said air flow, preferably by passing the disinfected and washed air flow through at least one catalytic filter or one activated carbon filter.
• The washing liquid is automatically renewed, so as to maintain the concentration of biocide in this liquid below a predefined threshold.
• The biocidal liquid is automatically renewed so as to maintain in this biocidal liquid a concentration of biocide within a predefined concentration range.
• The biocide concentration in the disinfected and washed air stream that is released into the surrounding air is less than or equal to 1ppm.
• The biocidal liquid is an aqueous solution containing at least one biocidal agent.
• The washing liquid is water or an aqueous solution.
• The step (b) of disinfection of the airflow is carried out by passing the airflow through a bath of biocidal liquid, preferably by injecting the airflow into this bath of biocidal liquid, below of the surface of this bath of biocidal liquid.
• The step (c) of washing the intermediate air flow is carried out by passing the intermediate air flow through a bath of washing liquid, preferably by injecting the air flow into this bath of washing liquid , below the surface of this washing liquid bath.
• The temperature of the biocidal liquid is lower than the temperature of the air flow at the inlet of the disinfection device.

The invention also relates to a disinfection installation comprising a disinfection device comprising a biocidal liquid which contains at least one biocidal agent, a washing device comprising a washing liquid, means for the forced circulation of a flow of air, which in operation make it possible (a) to capture in the surrounding air a flow of air which may be contaminated by microorganisms, (b) to pass said flow of air through the disinfection device and into contact with the biocidal liquid, so as to obtain, at the outlet of the disinfection device, an intermediate air flow which is at least partly disinfected, (c) passing said intermediate air flow through the washing device and in contact with the washing liquid, so as to produce at the outlet of the washing device a flow of disinfected and washed air (F3) and (d) to reject all or part of this flow of disinfected and washed air into the surrounding air.

More particularly, the installation of the invention may comprise the following additional and optional characteristics, taken separately, or in combination with each other:

• The biocidal liquid is an aqueous solution containing said at least one biocidal agent.
• The biocidal agent is hydrogen peroxide.
• The installation comprises a treatment device, which is adapted to act on a liquid, in order to confer said liquid biocidal properties or to reinforce the biocidal properties of said liquid, so as to obtain said biocidal liquid.
• Said processing device comprises one or more sources of emission of electromagnetic radiation, and in particular of UV radiation, said source or sources of emission of electromagnetic radiation preferably being immersed in said liquid.
• The concentration of said at least one biocidal agent in the biocidal liquid is between 1% and 20% by weight, and preferably between 5% and 10% by weight.
• The installation comprises at least one filter capable of lowering the concentration of at least biocide in the disinfected and washed air flow, before its discharge into the surrounding air, and preferably at least one catalytic filter or a charcoal.
• The washing liquid is water or an aqueous solution.
• The disinfection device comprises supply means capable of automatically renewing the biocidal liquid so as to maintain in this biocidal liquid a concentration of biocide within a predefined concentration range.
• The washing device comprises washing liquid supply means making it possible to automatically renew the washing liquid, so as to maintain the concentration of biocide in this washing liquid below a predefined threshold.
• The disinfection device comprises a bath of biocidal liquid and injection means suitable for causing the air flow to pass through said bath of biocidal liquid, preferably by injecting the flow of air into this bath of biocidal liquid, below the surface of this bath of biocidal liquid.
• The washing device comprises a bath of washing liquid and injection means making it possible to pass said intermediate air flow through said bath of washing liquid, preferably by injecting the intermediate air flow into this bath of washing liquid, below the surface of this bath of washing liquid.
• The installation includes a cooling device capable of cooling the flow of air captured in the surrounding air, before its disinfection by means of the biocidal liquid.

The invention also relates to a use of the above-mentioned installation for disinfecting surrounding air, where appropriate in the presence of living being(s), and in particular of human being(s).

Brief description of figures

The characteristics and advantages of the invention will appear more clearly on reading the detailed description below of several particular variant embodiments of the invention, which particular variant embodiments are described by way of non-limiting and non-exhaustive examples of the invention, and with reference to the accompanying drawings in which:

There is a schematic representation of a first particular embodiment of a disinfection installation of the invention;

There schematically represents a preferred example of a disinfection device and a washing device in cascade;

There is a schematic representation of a second particular embodiment of a disinfection installation of the invention.

Detailed description of the invention

With reference to the , there is shown schematically an installation 2 for disinfection of the surrounding air 1a in a space 1, this surrounding air 1a being likely to be contaminated by pathogenic microorganisms, and in particular bacteria, viruses, fungi, which can be dangerous for a living being, and in particular a human being, in case of inhalation of the surrounding air 1a.

In the context of the invention, the space 1 can be a closed space such as for example a room of a building or be an open or semi-open space. The invention can also be implemented to disinfect open air outdoors.

The disinfection of the surrounding air 1a can advantageously be carried out by means of this installation 2 of the invention with the presence of a living being, and in particular of a human being, in the surrounding air 1a, without any danger for a living being. inhaling the surrounding air 1a.

The disinfection installation 2 can either according to the invention be installed permanently or temporarily.

This disinfection installation 2 mainly comprises a disinfection device 20 and a washing device 21 mounted in cascade one behind the other, and means 22 for the forced circulation of an air flow, which makes it possible to capture in the surrounding air 1a a flow of air F1 likely to be contaminated by pathogenic microorganisms, to circulate this flow of air F1 successively through the two devices 20 and 21 and to reject in the surrounding air a flow of disinfected and washed air.

In the particular example illustrated, the disinfection device 20 and the washing device 21 are positioned outside the space 1. In another variant embodiment, the disinfection device 20 and the washing device 21 could be positioned inside space 1.

More particularly, the disinfection device 20 comprises an air flow inlet opening 200 and an air flow outlet opening 201 . The washing device 21 comprises an air flow inlet opening 210 and an air flow outlet opening 211. The means 22 for the forced circulation of an air flow comprise:

• a duct or set of ducts 220 which allows the inlet opening 200 of the washing device to communicate with the surrounding air 1a,
• a duct 221 connecting the discharge opening 201 of the disinfection device 20 to the inlet opening 210 of the washing device 21,

• a fan or air compressor 224,
• a duct 222 connecting the exhaust opening 211 of the washing device 21 to the inlet of the fan or air compressor 224, and
• a duct or set of ducts 223 allowing the outlet of the fan or air compressor 224 to communicate with the surrounding air 1a.

In operation, when the fan or air compressor 224 is running, an air flow F1, likely to be contaminated by pathogenic microorganisms, is captured by suction in the surrounding air 1a, with an air flow given, preferably adjustable.

This airflow F1 is conveyed by suction to the inlet opening 200 of the disinfection device 20 and is disinfected during its passage through this disinfection device 20.

To this end, the disinfection device 20 comprises a biocidal liquid, which contains at least one biocidal agent capable of eliminating or neutralizing the pathogenic microorganisms likely to contaminate the air flow F1. The disinfection device 20 can generally be constituted by any type of exchanger making it possible to bring into contact, by any means, said air flow F1 passing through the device 20 with the biocidal liquid, so as to obtain, in outlet of the disinfection device 20, an intermediate air flow F2 which is disinfected and no longer contaminated. This disinfected air flow F2 contains biocide at a concentration which depends in particular on the concentration of biocide in the biocidal liquid.

Preferably, but not necessarily, the biocidal agent is hydrogen peroxide (H ₂ O ₂ ), it being specified that the invention is however not limited to this particular biocide.

More particularly, the biocidal liquid can be an aqueous solution containing the biocidal agent and in particular hydrogen peroxide (H ₂ O ₂ ).

In another variant, the biocidal agent could for example be peracetic acid or the biocidal liquid could be bleach.

Depending on the application, the concentration by weight of biocide, and in particular of hydrogen peroxide (H ₂ O ₂ ), in the biocidal liquid can vary greatly from one application to another.

Preferably, the concentration by weight of biocide, and in particular of hydrogen peroxide (H ₂ O ₂ ), in the biocidal liquid is nevertheless between 1% and 20% by weight, and more preferably between 5 and 10% by weight .

Below 1% by weight of biocide, and in particular of hydrogen peroxide (H ₂ O ₂ ), the disinfection of the air flow F1 risks not being sufficient. Above 20% by weight of biocide, and in particular hydrogen peroxide (H ₂ O ₂ ), in the biocide liquid, the concentration of biocide in the disinfected air flow F2, at the outlet of the disinfection device 20 , risks being too high and complicating the washing of this air flow F2 in the washing device 21.

The disinfected air flow F2 is discharged through the discharge opening 201 of the disinfection device 20, is conveyed by suction to the inlet opening 210 of the washing device 21 and circulates through the washing device 21 by being brought into contact with a washing liquid.

The washing device 21 can generally be constituted by any type of exchanger making it possible to bring the air flow F2 into contact, by any means, with a washing liquid, so as to wash this air flow. F2 by capturing in the washing liquid at least part of the biocide contained in this air flow F2.

Whatever the type of washing device 21, the washing liquid can preferably be water or an aqueous solution.

More particularly and optionally, the washing liquid may also comprise one or more agents making it possible to neutralize the biocide or to transform it into a non-toxic product, and for example one or more catalysts promoting the catalytic decomposition of the biocide captured in the washing liquid. washing. For example, when the biocide is hydrogen peroxide, the catalyst can make it possible to obtain a decomposition reaction of hydrogen peroxide (H ₂ O ₂ ) in the form of water (H ₂ O) and oxygen (O ₂ ) and is for example a heavy metal or heavy metal salt (copper, cobalt, manganese, chromium, nickel, molybdenum, lead, iron, etc.).

At the outlet of the washing device 21, an air flow F3 is obtained which is disinfected and washed, with a concentration of biocide in the air flow F3 lower than the concentration of biocide in the intermediate air flow F2.

In addition, most of the time the chemical composition of the surrounding air 1a is not controlled, so that the surrounding air 1a can also contain toxic compounds, such as in particular, and not exhaustively, alcoholic compounds, aldehydes, ketones, hydrocarbons, BTEX (Benzene, Toluene, Ethylbenzene and Xylenes), Terpenes, chlorinated compounds or derivatives of these various toxic compounds. When the intermediate air flow F2 contains such toxic compounds or their derivatives, the washing of the intermediate air flow F2 also advantageously makes it possible to capture in the washing liquid at least a part of these toxic compounds or their derivatives present in the intermediate air flow F2.

The disinfected and washed air flow F3 is discharged through the discharge opening 211 of the washing device 21, passes through the fan or air compressor 224 and, at the outlet of the fan or air compressor 224, is released into the surrounding air 1a.

Preferably, the airflow F3 which is released into the surrounding air no longer contains biocide or contains biocide in a concentration low enough not to be toxic for a living being inhaling the surrounding air 1a, i.e. i.e. typically a biocide concentration of less than 1ppm when the biocide is hydrogen peroxide.

When the washing device 21 does not make it possible to sufficiently lower the concentration of biocide in the air flow F3, it is possible, optionally within the framework of the invention, to add downstream of the washing device 21 , one or more additional filtering devices 24, such as for example one or more activated carbon filters 24 making it possible to trap the biocide or one or more catalytic filters 24.

A catalytic filter, also commonly called a “catalyst”, is suitable for destroying the biocidal agent present in the air flow F3 by air by breaking down the biocidal agent into non-toxic products. For example, for an F3 air flow containing hydrogen peroxide, it is possible to use a catalytic filter containing as catalyst at least one heavy metal or heavy metal salt (copper, cobalt, manganese, chromium, nickel, molybdenum, lead , iron, etc.), and making it possible to obtain a decomposition reaction of hydrogen peroxide (H ₂ O ₂ ) in the form of water (H ₂ O) and oxygen (O ₂ ).

In the context of the invention, the disinfection device 20 can be any device making it possible to bring into contact, by any means, said air flow F1 passing through the device 20 with the biocidal liquid, so as to obtain at the outlet of the device disinfection 20 an intermediate air flow F2, which is disinfected and which is no longer contaminated.

Nevertheless, in a preferred variant embodiment, this disinfection device 20 is preferably a device of the type comprising ( ) an enclosure E1 containing a bath 202 of biocidal liquid 203 and injection means 204, which are adapted to introduce said flow of air F1 to be disinfected below the surface S1 of the bath 202 of biocidal liquid 203.

These injection means 204 may more particularly comprise a duct 204a comprising, for example in its upper part 204c, an inlet opening 204b corresponding to the aforementioned inlet opening 200 of the disinfection device 20. The lower part 204d of the injection conduit 204a is immersed in bath 202 of biocidal liquid 203 and has an evacuation opening 204e immersed in bath 202 of biocidal liquid 203.

In operation, the fan or compressor 224 extracts the air flow F1 from the surrounding air 1a and introduces it into the injection duct 204a through the intake opening 204b (200). This flow of air F1 escapes from the injection duct 204a through the evacuation opening 204e, and is therefore forced into the bath 202 of biocidal liquid 203, below the surface S1 of the bath 202 of biocidal liquid 203, rises towards the surface S1 of the bath of biocidal liquid, then escapes from the enclosure E1 through the evacuation opening 201, in the form of a flow of disinfected air F2.

In a particular variant embodiment, the disinfection device 20 may also comprise means 205 for supplying biocidal liquid ( - reserve 205a of biocidal liquid - hydraulic pump 205b for supplying enclosure E1 with biocidal liquid, hydraulic pump 205c for the evacuation of liquid outside of enclosure E), which in general are suitable to automatically renew the biocidal liquid 203 in the device 20, so as to maintain in this biocidal liquid 203 a concentration of biocide in a predefined concentration range.

In the context of the invention, the washing device 21 can be any device making it possible to bring into contact, by any means, said flow of air F2 passing through the device 21 with the washing liquid, so as to obtain at the outlet of the device disinfection 21 said air flow F3 disinfected and washed.

Nevertheless, in a preferred variant embodiment, this disinfection device 21 is preferably a device of the same type as the aforementioned disinfection device 20, that is to say comprising ( ) an enclosure E2 containing a bath 212 of washing liquid 213 and injection means 214, which are adapted to introduce said flow of air F2 to be washed below the surface S2 of the bath 212 of washing liquid 213.

These injection means 214 may more particularly comprise a duct 214a comprising, for example in its upper part 214c, an inlet opening 214b corresponding to the aforementioned inlet opening 210 of the washing device 21. The lower part 214d of the injection conduit 214a is immersed in the bath 212 of washing liquid 213 and comprises an evacuation opening 214e immersed in the bath 212 of washing liquid 213.

In operation, the fan or compressor 224 draws in the disinfected airflow F2 at the outlet of the disinfection device 20 and introduces it into the injection duct 214a through the inlet opening 214b (210). This flow of air F2 escapes from the injection duct 214a through the discharge opening 214e, and is therefore forced into the bath 212 of washing liquid 213, below the surface S2 of the bath 212 of washing liquid 213, rises towards the surface S2 of the bath of washing liquid, then escapes from the enclosure E2 through the evacuation opening 211, in the form of a flow of disinfected air and washed F3.

The bath 212 of washing liquid 213 can be the same throughout the treatment or can be renewed automatically, during the treatment, with uncontaminated washing liquid in order to maintain a low concentration of biocide captured in the bath 212 of washing liquid 213.

In another alternative embodiment, the air compressor or fan 224 could be mounted upstream of the disinfection device 20, so as to circulate by blowing the flow of air to be treated through the disinfection device 20 and through the washing device 21.

In the context of the invention, the flow rate of the fan or compressor 224 can be very different from one application to another and is not limiting of the invention.

Preferably, the temperature of the biocidal liquid 203 and the temperature of the washing liquid 213 are substantially at the same temperature and at a temperature lower than the temperature of the air flow F1 at the inlet of the disinfection device 20, so as to avoid overloading the air flow F3 with humidity which is discharged into the surrounding air 1a.

As the installation of the , during its passage through the disinfection device 20, the air flow F1 cools by taking on moisture, part of the biocidal liquid 203, evaporating in the device 21.

In a particular variant embodiment, in order to reduce the evaporation of the biocidal liquid 203, the installation can optionally ( ) include a cooling device 23, for example of the heat pump type or Pelletier effect cooling device, allowing the air flow F1 to be cooled (for example cooling from 3° C. to 6° C.) before its introduction into the disinfection device 20. The calories recovered by the cooling device 23 can optionally be reused to heat the surrounding air 1a.

We represented on the , another variant of a disinfection installation 2' which differs from the disinfection installation 2 of the by the implementation of a treatment device 206, which is adapted to act on the liquid 203 contained in the disinfection device 20, so as to confer in situ biocidal properties on this liquid 203, when the liquid coming from of the reserve 205a of liquid has no biocidal property, or in such a way as to reinforce the biocidal properties of this liquid 203 in situ, when the liquid coming from the reserve 205a already has biocidal properties.

For example, the liquid 203 can be water or an aqueous solution and the treatment device 206 can comprise one or more lamps immersed in the liquid 203 and capable of irradiating the liquid 203 with electromagnetic radiation, and in particular UV radiation. , making it possible to generate, in situ in the liquid, biocidal agents, such as for example ozone and/or free radicals such as for example hydroxyl radicals (OH•).

In this particular variant embodiment, the washing of the intermediate air flow F2 in the washing device 21 makes it possible to capture in the washing liquid at least part of the ozone present, where appropriate, in the intermediate air flow F2 , and preferably all of the ozone present, where appropriate, in the intermediate air flow F2.

In addition, in this particular variant embodiment, when the surrounding air 1a contains toxic compounds, such as in particular, and in a non-exhaustive manner, alcoholic compounds, aldehydes, ketones, hydrocarbons, BTEX (Benzene, Toluene , Ethylbenzene and Xylenes), Terpenes, chlorinated compounds or derivatives of these various toxic compounds, free radicals, such as for example hydroxyl radicals (OH•), which are created by means of UV radiation in the liquid of the device disinfection 21, in addition to their biocidal action, can also react chemically in this liquid with these toxic compounds and transform these toxic compounds into toxic by-products which can be found in the intermediate air flow F2. In this case, the washing of the intermediate air flow F2 also advantageously makes it possible to capture in the washing liquid at least a part of these toxic by-products and preferably all of these toxic by-products present where appropriate in the intermediate air flow F2.

Claims (30)

Process for disinfecting surrounding air (1a), during which (a) an air flow (F1) which may be contaminated by microorganisms is captured in the surrounding air (1a), (b) this flow is subjected of air (F1) to a disinfection treatment by bringing this air flow (F1) into contact with a biocidal liquid (203) containing at least one biocidal agent, so as to obtain an intermediate air flow (F2) at least partly disinfected, then (c) this intermediate air flow (F2) is subjected to washing by bringing this intermediate air flow (F2) into contact with a washing liquid (213), and (d) all or part of said disinfected and washed airflow (F3) is rejected into the surrounding air (1a). Process according to Claim 1, in which the biocidal liquid is obtained by adding at least one biocidal agent to a liquid solution. Method according to any one of the preceding claims, in which the concentration of the said at least one biocidal agent in the biocidal liquid (203) is between 1% and 20% by weight, and preferably between 5% and 10% by weight. A method according to any preceding claim, wherein the biocidal agent is hydrogen peroxide. A method according to any preceding claim, wherein the biocidal liquid (203) is obtained by treating a liquid so as to impart biocidal properties to said liquid or to enhance the biocidal properties of said liquid. Method according to any one of the preceding claims, in which the biocidal liquid (203) is obtained by irradiation of a liquid and in particular by UV irradiation. Method according to any one of the preceding claims, in which the flow of disinfected and washed air (F3) is filtered, before rejecting it into the surrounding air (1a) in order to lower the concentration of at least biocide in said disinfected and washed air flow (F3), preferably by passing the disinfected and washed air flow (F3) through at least one catalytic filter (24) or an activated carbon filter (24). Method according to any one of the preceding claims, in which the washing liquid (213) is automatically renewed, so as to maintain the concentration of biocide in this liquid below a predefined threshold. Method according to any one of the preceding claims, in which the biocidal liquid (203) is automatically renewed so as to maintain in this biocidal liquid a concentration of biocide within a predefined concentration range. Method according to any one of the preceding claims, in which the concentration of biocide in the stream of disinfected and washed air which is discharged into the surrounding air (1a) is less than or equal to 1ppm. A method according to any preceding claim, wherein the biocidal liquid (203) is an aqueous solution containing at least one biocidal agent. A method according to any preceding claim wherein the washing liquid (213) is water or an aqueous solution. A method according to any preceding claim, wherein step (b) of disinfecting the airflow (F1) is performed by passing the airflow (F1) through a bath (202) of liquid biocide (203), preferably by injecting the flow of air (F1) into this bath of biocidal liquid, below the surface (S1) of this bath of biocidal liquid. A method according to any preceding claim, wherein step (c) of washing the intermediate air stream (F2) is performed by passing the intermediate air stream (F2) through a bath (212) of washing liquid (213), preferably by injecting the flow of air into this bath of washing liquid, below the surface (S2) of this bath of washing liquid. Method according to any one of the preceding claims, in which the temperature of the biocidal liquid (203) is lower than the temperature of the air flow (F1) at the inlet of the disinfection device (20). Method according to any one of the preceding claims, in which the flow of air (F1) captured in the surrounding air (1a) is cooled, before its disinfection by means of the biocidal liquid (203). Disinfection installation comprising a disinfection device (20) comprising a biocidal liquid (203) which contains at least one biocidal agent, a washing device (21) comprising a washing liquid (213), means (22) for forced circulation of a flow of air, which in operation make it possible (a) to capture in the surrounding air (1a) a flow of air (F1) which may be contaminated by microorganisms, (b) to pass said flow of air (F1) through the disinfection device (20) and in contact with the biocidal liquid (203), so as to obtain, at the outlet of the disinfection device (20), an intermediate air flow (F2) at least partly disinfected, (c) passing said intermediate air flow (F2) through the washing device (21) and in contact with the washing liquid (213), so as to produce at the outlet of the device washing (21) a flow of disinfected and washed air (F3) and (d) rejecting all or part of this flow into the surrounding air (1a) of disinfected and washed air (F3). Installation according to claim 17, in which the biocidal liquid (203) is an aqueous solution containing the said at least one biocidal agent. Plant according to any one of Claims 17 to 18, in which the biocidal agent is hydrogen peroxide. Installation according to any one of Claims 17 to 19, comprising a treatment device (206), which is adapted to act on a liquid, in order to confer on said liquid biocidal properties or to reinforce the biocidal properties of said liquid, so as to obtaining said biocidal liquid (203). Installation according to claim 20, in which said processing device (206) comprises one or more sources of emission of electromagnetic radiation, and in particular of UV radiation, said source or sources of emission of electromagnetic radiation being preferably immersed in said liquid. Installation according to any one of claims 17 to 21, in which the concentration of said at least one biocidal agent in the biocidal liquid (203) is between 1% and 20% by weight, and preferably between 5% and 10% by weight. Installation according to any one of claims 17 to 22, comprising at least one filter (23) capable of lowering the concentration of at least biocide in the disinfected and washed air flow (F3), before its discharge into the surrounding air (1a), and preferably at least one catalytic filter (24) or an activated carbon filter (24). Installation according to any one of Claims 17 to 23, in which the washing liquid (213) is water or an aqueous solution. Installation according to any one of Claims 17 to 24, in which the disinfection device (20) comprises supply means (205) capable of automatically renewing the biocidal liquid (203) so as to maintain in this biocidal liquid a concentration of biocide in a predefined concentration range. Installation according to any one of Claims 17 to 25, in which the washing device (21) comprises washing liquid supply means making it possible to automatically renew the washing liquid (213), so as to maintain the concentration of biocide in this washing liquid below a predefined threshold. Installation according to any one of claims 17 to 26, in which the disinfection device (20) comprises a bath (202) of biocidal liquid (203) and injection means (204) able to cause the flow of air (F1) through said bath (202) of biocidal liquid (203), preferably by injecting the flow of air (F1) into this bath of biocidal liquid, below the surface (S1) of this bath of biocidal liquid. Installation according to any one of Claims 17 to 27, in which the washing device (21) comprises a bath (212) of washing liquid (213) and injection means (214) allowing said flow of intermediate air (F2) through said bath (212) of washing liquid (213), preferably by injecting the intermediate air flow (F2) into this bath of washing liquid, below the surface (S2 ) of this washing liquid bath. Installation according to any one of claims 17 to 28, comprising a cooling device (23) capable of cooling the flow of air (F1) captured in the surrounding air (1a), before its disinfection by means of the biocidal liquid ( 203). Use of the installation of any one of claims 17 to 29 to disinfect surrounding air, where appropriate in the presence of living being(s), and in particular human being(s).