Odor suppression method and odor suppression system

Abstract

To provide an odor suppression method and an odor suppression system which can effectively deactivate urease.SOLUTION: An odor suppression method radiates ultraviolet light whose main emission wavelength belongs to a wavelength band of 200 to 235 nm, to an object surface where urease is left. An odor suppression system has a light source for radiating the ultraviolet light whose main emission wavelength belongs to the wavelength band of 200 to 235 nm, the light source radiates the ultraviolet light to the object surface where urease is left. The light source is incorporated in the object forming the object surface, or in a place adjacent to the object.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and system for odor control. [Background technology]

[0002] In public toilets, etc., odors caused by products such as ammonia and amines due to residual urea can be a problem. For example, it is known that ammonia is produced by the reaction of urea with urease, a metabolic product of bacteria. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-255290 A Summary of the Invention [Problem to be solved by the invention]

[0004] Urease cannot be inactivated by ethanol, hypochlorous acid, etc. Also, surfactants capable of inhibiting urease activity are known (for example, Patent Document 1 below), but these surfactants are not effective unless they are in contact with urease for a long period of time, and are therefore not practical.

[0005] The present invention has been made in consideration of the above problems, and has an object to provide an odor suppression method and an odor suppression system that can effectively deactivate urease. [Means for solving the problem]

[0006] The odor suppression method according to the present invention is characterized in that the surface of an object on which urease remains is irradiated with ultraviolet light having a main emission wavelength in the wavelength band of 200 to 235 nm.

[0007] By irradiating with ultraviolet light whose main emission wavelength is in the wavelength range of 200 to 235 nm, urease can be effectively deactivated, which results in suppression of ammonia production and odor.

[0008] In this specification, the term "surface of an object on which urease remains" refers to a surface of an object on which urease exists and which may react with urea to generate ammonia.

[0009] In this specification, the term "main emission wavelength" refers to a wavelength λi in a wavelength range Z(λi) that shows an integrated intensity of 40% or more of the total integrated intensity in an emission spectrum, when a wavelength range Z(λ) of ±10 nm from a certain wavelength λ is defined on an emission spectrum.

[0010] In the odor suppression method according to the present invention, the integrated irradiation amount of the ultraviolet light on the surface of the object is 50 mJ / cm 2 It is preferable that the amount is equal to or more than that.

[0011] The cumulative dose of ultraviolet light is 50 mJ / cm 2 By doing so, the urease remaining on the surface of the object can be effectively deactivated.

[0012] In the odor suppression method according to the present invention, the integrated dose of the ultraviolet light on the surface of the object is 50 mJ / cm 2 one week after the start of the ultraviolet light irradiation. 2 It is preferable to determine the ultraviolet light irradiation operation so as to satisfy the above.

[0013] From the viewpoint of suppressing odors early, it is preferable to irradiate a large amount of ultraviolet light in a short period of time, but considering the case where it is desired to limit the amount of irradiation to the human body to a predetermined standard or less, it is preferable to set the light intensity and lighting time so that the amount of ultraviolet light irradiation is low when people are present, or to control so that irradiation is not performed, while setting the light intensity and lighting time so that more ultraviolet light is irradiated when people are absent. In this case, operation control can be performed based on the detection signal from the human detection unit. In this case, it is preferable to set the integrated irradiation amount of ultraviolet light to 50 mJ / cm2 in a short period of time when people are absent. 2 The above may be achieved.

[0014] In the odor suppression method according to the present invention, the integrated irradiation amount of the ultraviolet light on the surface of the object is 100 mJ / cm 2 It is preferable that the amount is equal to or more than that.

[0015] The cumulative dose of ultraviolet light is 100 mJ / cm 2 By doing so, the urease remaining on the surface of the object can be more effectively deactivated.

[0016] In the odor suppression method according to the present invention, the surface of an object on which urease remains is formed in the space within a toilet, and may be the inner surface of a toilet bowl. Since urea derived from urine is present on the inner surface of a toilet bowl that is placed in the space within a toilet, the odor suppression method according to the present invention is useful.

[0017] In the odor suppression method according to the present invention, the surface of an object on which urease remains is formed in the space within a toilet and may be a surface around the toilet bowl. The odor suppression method according to the present invention is useful because urea derived from scattered urine is present on surfaces around the toilet bowl that are located in the space within a toilet, specifically, on the surfaces of the floor and walls.

[0018] In the odor suppression method according to the present invention, the surface of an object on which urease remains may be formed in the space of a bathroom. The odor suppression method according to the present invention is useful because urea derived from urine and sweat, and urea contained in cosmetics, is present on the surfaces of objects placed in a bathroom, specifically, the surfaces of a bathtub, floor, wall, etc.

[0019] In the odor suppression method according to the present invention, the surface of an object on which urease remains is formed in the space within a washroom, and may be the inner surface of a washbowl. The odor suppression method according to the present invention is useful because urea derived from urine and sweat, and urea contained in cosmetics, is present on the inner surface of a washbowl placed in a washroom.

[0020] In the odor suppression method according to the present invention, the surface of the object on which urease remains may be formed inside a waste treatment chamber. Since urea derived from urine is present on the surface of the object placed in the waste treatment chamber, the odor suppression method according to the present invention is useful.

[0021] The odor suppression system according to the present invention includes a light source that irradiates ultraviolet light having a main emission wavelength in a wavelength band of 200 to 235 nm, The light source irradiates ultraviolet light onto the surface of the object on which urease remains, The light source is characterized in that it is incorporated in the object constituting the object surface or in a location adjacent to the object.

[0022] By irradiating with ultraviolet light whose main emission wavelength is in the wavelength range of 200 to 235 nm, urease can be effectively deactivated, which results in suppression of ammonia production and odor.

[0023] In the odor suppression system according to the present invention, the object may be any one of a toilet, a unit bath, a washbowl, and a waste sink. Since urea is present on the surfaces of a toilet, a unit bath, a washbowl, and a waste sink, the odor suppression system according to the present invention is useful.

[0024] In the odor control system according to the present invention, the object may be a wall or a floor, and the light source may be embedded in the wall or floor. With this configuration, the surface of the object on which urease remains can be irradiated with ultraviolet light more effectively than in the case where the light source is installed on, for example, a ceiling. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic diagram showing an example of a public restroom in which the odor suppression method and odor suppression system according to the present invention are expected to be implemented. [Diagram 2] Graph showing the light absorption characteristics of urease [Diagram 3] Graph showing the inactivation characteristics of urease [Figure 4] FIG. 13 is a schematic diagram showing a public toilet according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The odor suppression method and odor suppression system according to the present invention will be described with reference to the drawings. Note that the drawings are schematic illustrations, and the dimensional ratios in the drawings do not necessarily match the actual dimensional ratios, and the dimensional ratios between the drawings do not necessarily match.

[0027] 1 is a schematic diagram of an example of a public restroom in which the odor suppression method and odor suppression system according to the present invention are expected to be implemented. The odor suppression method and odor suppression system irradiates ultraviolet light L from a light source 1 onto an object surface.

[0028] A urinal 11, for example, is provided on the wall surface of the toilet 10. A gutter 12 is provided below the urinal 11. The upper part of the gutter 12 is covered with a grating 13. A stained stone 14 is attached to the floor below the urinal 11. A floor tile 15 is attached to the floor of the toilet 10. A light source 1 is installed on the ceiling of the toilet 10.

[0029] The odor generated in toilets comes from feces or urine. In particular, in toilets in train stations, which are used by many people, ammonia generated from urine is often a problem. The mechanism by which ammonia is generated is as follows.

[0030] First, urea in urine is broken down into ammonium ions by urease, a metabolic product of bacteria. Then, the pH rises due to the increase in the concentration of ammonium ions. Next, when p rises and the pH exceeds 7, for example, the ammonium ions turn into ammonia, causing an odor.

[0031] Urease is produced by urease-producing bacteria. Examples of urease-producing bacteria include Pseudomonas aeruginosa, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Klebsiella pneumoniae, Klebsiella oxytoca, and the like. In other words, the amount of ammonia produced can be suppressed by reducing the amount of urease and urease-producing bacteria involved in the production of ammonia. This can suppress the problem of ammonia odor in places that are not well cleaned, such as public toilets.

[0032] Pseudomonas aeruginosa is a bacterium present in familiar living environments, but as described above, the urease produced by Pseudomonas aeruginosa reacts with urea to generate ammonia, which becomes a problem. Places where ammonia can be generated by residual urease include toilets, bathrooms, washrooms, waste treatment rooms in hospitals, etc. In toilets, urea derived mainly from urine can be the source of ammonia, while in bathrooms and washrooms, urea derived from urine and sweat or urea contained in cosmetics can be the source of ammonia, and in waste treatment rooms, urea derived mainly from urine can be the source of ammonia. Therefore, by inactivating the urease remaining on the surfaces of objects placed in the space inside the toilet, bathroom, washroom, or waste treatment room, the generation of ammonia can be suppressed as a result.

[0033] If the amount of urease that produces 1 μmol of ammonium ion from urea in 1 minute under conditions of 25° C. and pH 7 is defined as 1 unit, then, although it varies depending on ventilation conditions, for example, when there are 1000 units or more of urease in the toilet 10, the ammonia odor is easily perceived. The amount of urease remaining on the surface of an object can be measured, for example, by using a commercially available urease activity measurement kit.

[0034] In the course of conducting research into odor suppression methods, the present inventors have found that ultraviolet light whose main emission wavelength is in the wavelength band of 200 to 235 nm is not only less harmful to the human body, but also has a high effect of inactivating urease. Moreover, ultraviolet light whose main emission wavelength is in the wavelength band of 200 to 235 nm also has the effect of sterilizing urease-producing bacteria. Therefore, the odor suppression method according to the present invention irradiates the surface of an object on which urease remains with ultraviolet light L whose main emission wavelength is in the wavelength band of 200 to 235 nm. The odor suppression method preferably irradiates the surface of an object on which urease remains with ultraviolet light L whose main emission wavelength is in the wavelength band of 200 to 230 nm.

[0035] Figure 2 is a graph showing the light absorption characteristics of urease, and shows the absorbance ratio when the absorbance at 254 nm, known as the bactericidal line, is set to "1". Figure 3 is a graph showing the inactivation characteristics of urease. As shown in Figure 2, urease has the property of absorbing light better at shorter wavelengths. In particular, it is known that the absorbance of proteins is significantly higher for ultraviolet light in the wavelength band shorter than 240 nm, and it can be seen from Figure 2 that the absorbance of urease, an enzyme, is also significantly higher. It can also be seen that the absorbance of ultraviolet light with a wavelength of 240 nm is 1.2 times higher than that of 254 nm. It is also shown that the absorbance is 1.3 times higher at a wavelength of 235 nm and 1.4 times higher at a wavelength of 230 nm.

[0036] Moreover, as shown in Figure 3, it is clear that ultraviolet light with a main emission wavelength of 222 nm has an extremely high inactivation effect compared to ultraviolet light with a main emission wavelength of 254 nm. This is because urease absorbs light better at shorter wavelengths, with the absorbance ratio at the peak wavelength of 222 nm being 1.6 times higher, and furthermore, shorter wavelengths have higher photon energy, so that ultraviolet light at 222 nm has a significantly improved urease inactivation property compared to ultraviolet light at 254 nm.

[0037] It is known that ultraviolet light with a wavelength of less than 240 nm has a low effect on the human body. From the viewpoint of further reducing the effect on the human body, it is more preferable that the main emission wavelength of the ultraviolet light L emitted from the light source 1 belongs to the wavelength band of 200 to 235 nm, and more preferably the main emission wavelength belongs to the wavelength band of 200 to 230 nm. This is also preferable from the viewpoint of more effectively inactivating the remaining urease.

[0038] As shown in Figure 3, ultraviolet light with a main emission wavelength of 222 nm has an integrated irradiation dose of 30 mJ / cm 2 Approximately 87% of urease was inactivated at an accumulated irradiation dose of 50 mJ / cm 2 Approximately 93% of urease was inactivated at an accumulated irradiation dose of 100 mJ / cm 2 Approximately 100% of the urease is inactivated at this dose. Therefore, the cumulative dose of ultraviolet light is 30 mJ / cm 2 More preferably, it is 50 mJ / cm or more. 2 More preferably, it is 100 mJ / cm or more. 2 It is particularly preferable that the ultraviolet light having a main emission wavelength of 222 nm has an integrated irradiation dose of 5 mJ / cm2 or more. 2 It is possible to inactivate urease-producing bacteria to such an extent that new production of urease can be suppressed.

[0039] The odor suppression system of this embodiment includes a light source 1 that irradiates ultraviolet light L. The ultraviolet light L is irradiated from the light source 1 to an object surface on which urease remains. In the example of Fig. 1, the object surface is formed in the space within a toilet 10, and is the inner surface of a urinal 11 or surfaces around the urinal 11 (surfaces of a gutter 12, a grating 13, a soiling stone 14, a floor tile 15, a wall, etc.).

[0040] 1, the light source 1 is attached to the ceiling, but the light source 1 may be embedded in the ceiling or wall. If embedded, at least the surface from which the ultraviolet light L is extracted may be covered with a material that is transparent to the ultraviolet light L.

[0041] The light source 1 is configured to emit ultraviolet light L whose main emission wavelength belongs to a wavelength band of 200 to 235 nm. As an example, the light source 1 is configured with an excimer lamp. The excimer lamp has a discharge vessel in which a light emitting gas is sealed. The light emitting gas is made of a material that emits ultraviolet light L whose main emission wavelength is 190 to 240 nm during excimer emission. As an example, the light emitting gas includes KrCl. When the light emitting gas includes KrCl, the excimer lamp emits ultraviolet light L whose main peak wavelength is 222 nm or thereabouts.

[0042] In this specification, the term "main peak wavelength" refers to the wavelength at which the light intensity in the emission spectrum is at its maximum value. In addition, in this specification, the term "main emission wavelength" refers to the wavelength at which the light intensity in the emission spectrum is at least 50% of the light intensity at the main peak wavelength.

[0043] However, the light source 1 is not limited to a specific embodiment as long as it emits ultraviolet light whose main emission wavelength is in the wavelength range of 200 to 235 nm. That is, the light source 1 may be a solid-state light source such as an LED or a laser diode instead of an excimer lamp.

[0044] The odor suppression system includes a lighting control unit (not shown) that controls the operation of light source 1. The odor suppression system may also include a human detection unit (not shown) that detects a human body present in the space of toilet 10. The human detection unit is, for example, an optical sensor or a camera.

[0045] As mentioned above, ultraviolet light with a main emission wavelength in the 200-235 nm wavelength band has a relatively high absorbance for urease compared to 254 nm ultraviolet light, which is a sterilizing radiation, and it is expected that irradiating the surface of an object with ultraviolet light in this wavelength band will promote the inactivation of urease. In this case, the cumulative irradiation dose of ultraviolet light L on the surface of the object is 50 mJ / cm2 one week after the start of irradiation with ultraviolet light L. 2 In this manner, it is preferable to determine the irradiation operation of the ultraviolet light L. Here, the irradiation operation of the ultraviolet light L refers to the illuminance, irradiation time, and the like of the ultraviolet light. For example, the effective irradiation operation may be based on the lighting operation cycle when a person is present, assuming that the daytime activity time is 8 hours. Specifically, the illuminance X [mW / cm 2 ], the ON duty ratio Y of the lighting cycle [lighting time / lighting cycle], and the activity time Z [28,800 seconds] are multiplied to obtain the estimated daily exposure [mJ / cm 2 ] is 7.2 mJ / cm 2 By setting the irradiation operation to above 50 mJ / cm after one week, 2 The above can be achieved. In addition, for example, the effective irradiation operation when the lighting operation cycle when no one is present may be adopted, assuming that the absence of people is for 5 hours, such as at night. Specifically, the illuminance X [mW / cm of ultraviolet light irradiated onto the surface of an object may be expressed as 2 ], the ON duty ratio Y [lighting time / lighting cycle] of the lighting operation cycle when no one is present, and the estimated daily irradiation amount [mJ / cm2] multiplied by the downtime Z [18,000 seconds] 2 ] is 7.2 mJ / cm 2 By setting the irradiation operation to above 50 mJ / cm after one week, 2 The above can be achieved. The desired dose is 100 mJ / cm 2 If this is the case, the expected daily exposure is 14.3 mJ / cm 2 By performing the above-described irradiation operation, an effective irradiation operation can be performed.

[0046] The cumulative dose of ultraviolet light L on the object surface was 50 mJ / cm 48 hours after the start of irradiation with ultraviolet light L. 2 It is more preferable to determine the irradiation operation of the ultraviolet light L so that the above is satisfied. From the viewpoint of not only inactivating urease but also inhibiting the proliferation of urease-producing bacteria, it is desirable to irradiate a sufficient amount of ultraviolet light L within 48 hours. For example, the effective irradiation operation may be based on the lighting operation cycle when a person is present, assuming that the daytime activity time is 8 hours. Specifically, the illuminance X [mW / cm 2 ], the ON duty ratio Y of the lighting cycle [lighting time / lighting cycle], and the activity time Z [28,800 seconds] are multiplied to obtain the estimated daily exposure [mJ / cm 2 ] is 25 mJ / cm 2 By setting the irradiation operation to above, the result is 50 mJ / cm after 48 hours. 2 The above can be achieved. In addition, for example, the effective irradiation operation when the lighting operation cycle when no one is present may be adopted, assuming that the absence of people is for 5 hours, such as at night. Specifically, the illuminance X [mW / cm of ultraviolet light irradiated onto the surface of an object may be expressed as 2 ], the ON duty ratio Y [lighting time / lighting cycle] of the lighting operation cycle when no one is present, and the estimated daily irradiation amount [mJ / cm2] multiplied by the downtime Z [18,000 seconds] 2 ] is 25 mJ / cm 2 By setting the irradiation operation to above, the result is 50 mJ / cm after 48 hours. 2 The above can be achieved. The desired dose is 100 mJ / cm 2 If this is the case, the expected daily exposure is 50 mJ / cm 2 By performing the above-described irradiation operation, an effective irradiation operation can be performed.

[0047] It is also desirable to inactivate urease in a shorter time, and the cumulative dose of ultraviolet light L on the object surface is set to 50 mJ / cm 24 hours after the start of irradiation with ultraviolet light L. 2 The irradiation operation of the ultraviolet light L may be determined so as to achieve the above. This makes it possible to inactivate most of the produced urease within a day, and more effectively prevents the perception of an unpleasant odor. For example, the effective irradiation operation may be based on the lighting operation cycle when a person is present, assuming that the daytime activity time is 8 hours. Specifically, the illuminance X [mW / cm 2 ], the ON duty ratio Y of the lighting cycle [lighting time / lighting cycle], and the activity time Z [28,800 seconds] are multiplied to obtain the estimated daily exposure [mJ / cm 2 ] at 50 mJ / cm 2 The above is the irradiation operation. In addition, the effective irradiation operation when the lighting operation cycle when no one is present may be adopted, assuming that the absence of people during the night is 5 hours. Specifically, the illuminance X [mW / cm 2 ], the ON duty ratio Y [lighting time / lighting cycle] of the lighting operation cycle when no one is present, and the estimated daily irradiation amount [mJ / cm2] multiplied by the downtime Z [18,000 seconds] 2 ] at 50 mJ / cm 2 The above is the irradiation operation. The desired dose is 100 mJ / cm 2 If it is more than this, the expected daily exposure is 100mJ / cm2, as above. 2 The above irradiation operation is set.

[0048] In addition, the ultraviolet light L does not need to be continuously irradiated, and may be irradiated intermittently. In addition, the ultraviolet light L may be irradiated in a predetermined manner when no one is present, and the illuminance of the ultraviolet light L may be reduced when a person is present. Furthermore, when no one is present, a predetermined irradiation operation may be continued until the integrated irradiation amount of the ultraviolet light L reaches a target value, and after the target value is reached, the light source 1 may be turned off.

[0049] Although the embodiments of the present invention have been described above based on the drawings, the specific configuration should not be considered to be limited to these embodiments. The scope of the present invention is indicated not only by the description of the above embodiments but also by the claims, and further includes all modifications within the meaning and scope of the claims.

[0050] The structures employed in the above-described embodiments can be employed in any other embodiment. The specific configurations of each part are not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. Furthermore, one or more of the configurations, methods, etc. relating to the various modified examples described below may be arbitrarily selected and employed in the configurations, methods, etc. relating to the above-described embodiments.

[0051] In the above embodiment, a urinal 11 is provided in the toilet 10, but a toilet bowl may also be provided.

[0052] In the above embodiment, the light source 1 is attached to the ceiling, but the present invention is not limited to this. The light source 1 may be embedded in the ceiling.

[0053] Furthermore, the light source 1 may be incorporated in the urinal 11 or a location adjacent to the urinal 11. For example, the light source 1 may be disposed on the bottom surface of the urinal 11, as shown in Fig. 4. This allows the ultraviolet light L to be effectively irradiated onto the surface of the gutter 12 or the grating 13.

[0054] Also, for example, the light source 1 may be embedded in the floor as shown in FIG. 4. Here, the light source 1 is embedded in a stain dripping stone 14, but it may be embedded in a floor tile 15. Also, for example, the light source 1 may be embedded in a wall, although not shown. Furthermore, for example, the light source 1 may be embedded in a urinal 11, although not shown. When embedded, at least the surface from which the ultraviolet light L is extracted may be covered with a material that is transparent to the ultraviolet light L. At least one light source 1 is provided in the toilet 10.

[0055] In the above embodiment, a toilet 10 is shown as a place where the odor suppression method and odor suppression system are assumed to be implemented, but the present invention is not limited thereto. The odor suppression method and odor suppression system may be implemented, for example, in a bathroom, washroom, waste disposal room, etc. Examples of objects in which urease remains include a unit bath (including a bathtub), a wash basin, and a waste sink. [Explanation of symbols]

[0056] 1:Light source 10: Toilet 11: Urinal 12: Gutter 13: Grating 14: Dirty stone 15:Floor tiles L: Ultraviolet light

Claims

1. An odor control method comprising irradiating an object surface on which urease remains with ultraviolet light having a main emission wavelength in the wavelength range of 200 to 235 nm.

2. The integrated irradiation dose of the ultraviolet light on the object surface is 50 mJ / cm ２ 2. The odor control method according to claim 1, wherein the odor control method comprises the steps of:

3. The cumulative dose of the ultraviolet light on the surface of the object is 50 mJ / cm 1 week after the start of the ultraviolet light irradiation. ２ 3. The odor control method according to claim 2, wherein the ultraviolet light irradiation operation is determined so as to satisfy the above.

4. The integrated irradiation dose of the ultraviolet light on the object surface is 100 mJ / cm ２ 2. The odor control method according to claim 1, wherein the odor control method comprises the steps of:

5. The surfaces on which urease remains are formed in the space inside the toilet, 5. The odor control method according to claim 1, wherein the odor control method is applied to the inner surface of a toilet bowl.

6. The surfaces on which urease remains are formed in the space inside the toilet, 5. The odor control method according to claim 1, wherein the odor control method is applied to a surface around a toilet bowl.

7. 5. The odor control method according to claim 1, wherein the surface of the object on which urease remains is formed in a space within a bathroom.

8. The surfaces on which urease remains are formed in the space inside the washroom.

5. The odor suppression method according to claim 1, wherein the odor suppression method is applied to the inner surface of a wash basin.

9. 5. The odor control method according to claim 1, wherein the surface of the object on which urease remains is formed inside a waste treatment chamber.

10. The present invention includes a light source that irradiates ultraviolet light having a main emission wavelength in a wavelength band of 200 to 235 nm, The light source irradiates ultraviolet light onto the surface of the object on which urease remains, The odor control system is characterized in that the light source is incorporated into an object that constitutes the object surface or in a location adjacent to the object.

11. 11. The odor control system according to claim 10, wherein the object is one of a toilet, a unit bath, a wash basin, and a waste sink.

12. 11. The odor control system of claim 10, wherein the object is a wall or a floor, and the light source is embedded in the wall or floor.

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