JPH05115540A - Sterilizing device by ozone for infective waste and sterilizing treatment using this device - Google Patents

Abstract

PURPOSE:To provide an infective waste sterilizing device and sterilizing method for easily, effectively and perfectly sterilizing infective bacteria adhered to a medical waste. CONSTITUTION:A sterilizing device is formed of a sealed sterilizing chamber 1, an ozone generating device 2, a humidifying device 3, a gas suction pump 4, a sterilizing-bacteria removing device 5 such as ultraviolet ray or a membrane filter, and an exhaust ozone treating device 6. The ozone generating device 2 is directly connected to the sealed sterilizing chamber 1 in the form allowing the humidification from the humidifying device 3. The humidifying device 3 and the gas suction pump 4 are directly connected to the sealed sterilizing chamber 1, and the sterilizing-bacterial removing device 5 and the exhaust ozone treating device 6 are directly connected to the gas suction pump 4. The sterilization is conducted by using ozone as a sterilizing agent in a phase having the ozone concentration at the time of sterilization of 50mg/l or more keeping a relative humidity of 90 or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infectious waste sterilization apparatus and a sterilization method using this apparatus.

[0002]

2. Description of the Related Art Infectious waste is often treated as general waste without being sterilized, and there are many cases of violation of the Industrial Waste Management Law. The Ministry of Health and Welfare has already established the “medical waste treatment guidelines” to properly dispose of infectious waste, and has been implementing it from April 1, 1990. Requires a simple sterilization device. In other words, in principle, incineration or autoclave is used for the treatment in the facilities of medical institutions (Medical waste treatment guidelines P.2).
3) The incineration method is not always a preferable method because of problems such as generated gas. For example, plastics, which are often used in disposable medical devices, have problems of damage to the incinerator due to high heat during incineration and environmental pollution due to exhaust gas during incineration, and infectious waste with a high protein content. In such cases, there are problems such as foul odor and emission of nitrogen oxides when incinerated. Therefore, in many cases it is not desirable to operate the incineration facility from the viewpoint of conservation of the surrounding living environment, and it is a cause of concern for the people involved in operating the guideline. Sterilization methods other than incineration include autoclave, dry heat, boiling sterilization, etc., but the former two are expensive because they require a long time for processing, and boiling sterilization is not always a simple method. Absent. Due to such circumstances, it is often the case that the treatment company is outsourced, but the treatment company cannot adopt the cost-expensive method such as small-volume boiling sterilization. encounter.

[0003]

In order to respond to such a social situation, the present invention provides a simple, efficient and complete method for processing large amounts or small amounts in facilities of processors or medical institutions. It is an object of the present invention to provide a device for sterilization.

[0004]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, the apparatus of the present invention includes an infectious waste treatment chamber that seals and treats infectious waste, an ozone gas generator, a device that humidifies the treatment chamber, an exhaust system that makes the treatment chamber a negative pressure, and an exhaust system. It consists of an ozone decomposing device, and each of the latter four devices is connected to an infectious waste treatment room. Negative pressure in the treatment chamber is to ensure that ozone gas is introduced into a small space such as a syringe, but the air in the infectious waste treatment chamber discharged when negative pressure is applied is It is also a feature of the apparatus of the present invention that the apparatus of the present invention is provided with a sterilizer for bacteria contained therein, for example, an ultraviolet sterilizer or a membrane filter.

In the method of the present invention, the sterilization treatment of infectious waste with ozone is performed by using the above apparatus.
The feature is that it is performed in a gas phase of 0% or more.

Next, the sterilization apparatus and sterilization method of the present invention will be described in detail with reference to the drawings. In FIG. 1, 1 is a closed sterilization processing chamber, 2 is an ozone generator, 3 is a humidifier,
Reference numeral 4 is a gas suction pump, 5 is a sterilization / sterilization device for ultraviolet rays or membrane filters, and 6 is an exhaust ozone treatment device.

The closed sterilization processing chamber 1 made of ozone-resistant metal or the like has an opening / closing port for accommodating an ozone-resistant metal basket filled with infectious waste. The opening / closing port is sealed with ozone-resistant silicone rubber or the like so that ozone gas does not leak outside. Processing room 1
In order to ensure that ozone gas sufficiently enters a small space such as the inside of a syringe to be treated, the pump 4 is used to lightly reduce the pressure to a negative pressure beforehand, but to sterilize the exhaust air at that time, 25
By connecting the sterilization / disinfection device 5 such as ultraviolet rays having a main wavelength of 4 nm ultraviolet rays or a membrane filter to the processing chamber 1, the exhaust air is ultraviolet-sterilized or sterilized and is discharged to the outside. When the processing chamber 1 becomes negative pressure, ozone gas is supplied to the processing chamber 1
And sterilize by introducing into the above at normal pressure or positive pressure. As the ozone generator 2, a known one such as a corona discharge type or an electrolysis type is used.

The inventors of the present invention have made extensive studies on the sterilization method using the above sterilization apparatus, and found that the relative humidity is 9%.
It was found that ozone treatment was effective at 0% or more, and the sterilization method of the present invention was completed.

According to the experiments by the present inventors, the relationship between the survival rate of spores in the ozone atmosphere and the relative humidity is as shown in Table 1.

[0010]

[Table 1]

Table 1 shows Baci used as an index of sterilization.
llus subutilis (IFO 3134) Ozone was introduced after adjusting the relative humidity of the treatment room where the spores are alive, and Bacillus subutilis
The survival rate of Bacillus subutilis was determined using the contact time of utilis (IFO 3134) spores and ozone and the relative humidity in the treatment room as parameters. From this table, relative humidity 90
It can be seen that effective sterilization is difficult unless it is at least%. It is also clear from Table 1 that it is more effective to increase the humidity in the sterilization chamber before introducing ozone. That is, almost all spores die over a long time without humidification before introducing ozone (see Table 1), but the humidity before introduction is 8%.
When it is 0% -preferably 90% or more, the sterilization time is significantly shortened. Various ozone concentrations suitable for sterilization using the closed ozone sterilization apparatus of the present invention were also examined, and the following results were obtained. That is, blood, blood products, etc. as shown in Table 2 are mixed in actual medical waste, and since these contain proteins and the like that are rapidly decomposed by ozone, the added ozone is absorbed by these and lowers the concentration. Therefore, in actual operation, it is necessary to have an ozone concentration of 50 mg / l or more at a relative humidity of 90% or more.

The present inventors determined the sterilization method as follows based on the experimental results. That is, the hermetically sealed processing chamber 1 is set to a normal pressure or a slight negative pressure at a relative humidity of 80 to 90%, an ozone-containing gas having a relative humidity of 90% or more is introduced therein, and ozone is exposed for a certain period of time at an ozone concentration of 50 mg / l or more. After doing
Ozone is excluded from the closed processing chamber 1. The air containing ozone is released to the outside through the exhaust ozone decomposing device 6, and the ozone decomposing method may be a known method using activated carbon, a catalyst, or the like. Next, Table 2 shows the types and specific examples of infectious waste.

[0013]

[Table 2]

In Table 2, since blood-related substances, culture media and the like react with ozone and the like, the ozone concentration is 1 to 5 mg / hr in a steady state (after the completion of the reaction of proteins and ozone with ozone). Therefore, it is necessary to set the introduced ozone concentration high. In addition, when disposing of waste instruments with cavities such as waste syringes and needles, these instruments form a narrow cavity. It is better to adopt a method in which the inside of the sterilization chamber 1 is slightly negative pressure before introducing ozone.

No conventional example has been found in which the vapor phase sterilization method using ozone described above is applied to the treatment of infectious wastes. The conventional vapor phase sterilization method is a medical device to which ethylene oxide or γ-ray irradiation is applied. In addition to sterilization methods (including disposable medical equipment), sterilization methods for safety cabinets for microbiological experiments and clean rooms in hospitals using formalin fumigation and UV irradiation are only known.

The present inventors have found in the basic study shown in Table 1 that the spores can be easily sterilized at an ozone concentration of 1 to 5 mg / l (relative humidity 90%). Compared with other sterilant concentrations, ethylene oxide 400-1000 mg / l (relative humidity 30-50%
), 3-10 mg / l for formalin (80% relative humidity)
.About.90%), with β-propiolactone 0.2-
It is 2 mg / l (when the relative humidity is 70% or more). Therefore, when the strength of spore sterilizing action is compared based on the concentration, the order is β-propiolactone> ozone ≧ formalin >> ethylene oxide. That is, ozone has a sterilizing power that is not inferior to that of currently used gas phase sterilants, and this is also an example showing that the infectious waste treatment method of the present invention has more advantages than other treatment methods. See.

Conventional gas phase sterilants include: Complexity of sterilization operation ,. It takes a long time to ventilate after use. There are problems such as danger to workers derived from. On the other hand, ozone, which is used as a gas phase sterilizer in the present invention, has some advantages in terms of simplicity of sterilization operation. That is, since the ozone generation system is easy to electrically control, most of the operations can be automated. It also reduces the risk of worker exposure to germicides. Further, since formalin and ethylene oxide have strong adsorptivity, ozone can be easily removed while the bactericide remains for a long time even after ventilation after sterilization treatment. Therefore, the method of the present invention has advantages such as higher safety than other conventional methods and a shorter total time required for processing.

[0018]

According to the present invention, infectious bacteria and the like attached to medical waste can be completely sterilized. That is, these sterilizers are completely sterilized by contact with ozone gas under a constant temperature condition, and the remaining ozone used is decomposed by an exhaust ozone decomposer. When the exhaust of ozone is completed, the waste inside can be taken out immediately. Since ozone has a large destructive power, it causes deterioration of waste other than sterilization, but this is completely out of the question for waste, so the method of applying the strong destructive decomposition power of ozone is infectious waste. The industrial significance of processing objects is enormous.

[Brief description of drawings]

FIG. 1 is a system diagram of a sterilization apparatus according to the present invention.

[Simple explanation of symbols]

1 Closed Sterilization Treatment Room 2 Ozone Generator 3 Humidifier 4 Gas Suction Pump 5 Sterilization-Bactericidal Device such as Ultraviolet or Membrane Filter 6 Waste Ozone Treatment Device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kotaro Yamane, 315 1 Minamihanashima Mukomachi, Matsudo City, Chiba Prefecture, Japan Medex Co., Ltd. (72) Inventor Tatsutoshi Hayashi, 315 1 Minamihanashima Mukomachi, Matsudo City, Chiba Prefecture In Japan Medex Co., Ltd. (72) Inventor Hiroshi Suzuki 315 1 Mukomachi, Minamihanajima, Matsudo City, Chiba 1 Shares in Nippon Medex Co., Ltd.

Claims (7)

[Claims] 1. A sterilization treatment of infectious waste by ozone, which comprises connecting an ozone gas generator, a humidifier, an exhaust system for making a negative pressure in the treatment chamber, and an exhaust ozone decomposing device to a sealable infectious waste treatment chamber. apparatus. 2. The apparatus according to claim 1, wherein an ultraviolet sterilizer or a membrane filter is provided at the outlet of the exhaust system for making the inside of the infectious waste treatment chamber a negative pressure. 3. A pipe is provided which mixes water supplied from the humidifier with ozone-containing gas supplied from the ozone gas generator and supplies the mixed water to the infectious waste treatment device. 1 or 2 devices. 4. In the sterilization treatment of infectious waste by ozone using the apparatus according to any one of claims 1 to 3, the sterilization treatment is performed in a gas phase having a relative humidity of 90% or more. A method for sterilizing substances with ozone. 5. The method according to claim 4, wherein the infectious waste treatment chamber is set to a negative pressure in advance before introducing ozone. 6. The method according to claim 4 or 5, wherein the relative humidity in the infectious waste treatment chamber is raised to 80% or more in advance just before the introduction of ozone. 7. The method according to claim 4, wherein the exhaust gas for making the inside pressure of the infectious waste treatment chamber negative is treated by an ultraviolet sterilizer or a membrane filter.