JPH0678983A - Method and device for disposing medical waste - Google Patents

Abstract

PURPOSE:To provide a method and device particularly suitable for hospital internal disposal capable of surely sterilizing and volume-reducing medical waste at a relatively low temperature within a short time. CONSTITUTION:A medical waste put in a vessel 1 is sterilized by filling the vessel with a high pressure steam of 110 deg.C to 150 deg.C for 10 minutes or more. Prior to this, the waste is pulverized by a rotary knife 5 provided in the vessel 1 to form splinters 6, so that the capacity can be reduced, and steam can be delivered to fine parts. The wall in the vessel 1 and the rotary knife 5 are also sterilized together with the splinters 6. Since the exhaust air from the vessel 1 is also sterilized by a sterilizing filter 11 before release, no infective material is present after a series of treatments is finished, and there is no possibility of secondary contamination.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for sterilizing and reducing the volume of infectious waste discharged by medical activities.

[0002]

2. Description of the Related Art Many of the wastes discharged by medical activities have infectious pathogens attached to them, and careless handling of them causes medical institutions to play an important role in maintaining human health. Since the discharged waste can cause illness, medical waste, particularly infectious waste, is conventionally separated in a medical institution and collected, transported and incinerated by a specialized waste disposal company.

[0003]

However, there are not many processors who handle wastes that pose a risk of infection,
On the other hand, as is typical of disposable syringes, from the viewpoint of safety and efficiency of medical treatment, so-called disposable medical devices have been increasingly used in recent years, and infectious agents discharged from medical institutions have become more frequent. The amount of medical waste is increasing year by year. For this reason, the contracted disposal price of infectious wastes by medical waste disposal companies is unstable and high, which leads to an increase in medical activity costs.

Further, in the case of collection, transportation and processing by a processing company, there is a possibility that infectious waste may be scattered due to an accident on the way, and a method of monitoring by a manifest system etc. is also available. Has been adopted,
There remains concern about whether or not the final processing was done reliably.

Therefore, the treatment cost of the infectious medical waste in the discharged medical institution is stable and inexpensive, and there is no danger of transportation and the infectivity can be surely eliminated (hereinafter referred to as " There is a strong demand for a method and device for "in-hospital treatment".

Various methods such as crushing, incineration, heating, and sterilization with a chemical solution have been considered as in-hospital treatment methods, and some proposals for an apparatus for realizing them have been made. However, these in-hospital treatment methods have the following problems.

That is, the crushing process is suitable as a volume reduction process before being handed over to a processor, but since sterilization is not performed at all, the crushed infectious waste is still infectious, and special treatment therefor is necessary. is necessary. In addition, there is a possibility that infectious pathogens may be attached to the device used for crushing infectious wastes, and special handling is required when handling them.

Although the incineration process is the most reliable from the viewpoint of sterilization, since most medical waste is made of plastic, the exhaust gas generated when the plastic is decomposed during incineration contains harmful substances. Therefore, secondary pollution becomes a problem and large equipment is required for exhaust gas treatment. In addition, the incinerator that emits high heat requires a large installation space,
In particular, it is unsuitable for equipment in hospitals in urban areas.

In the case of heating that does not result in incineration, the sterilizing effect cannot be expected unless the inside of the waste is heated to a temperature of about 200 ° C. or more in dry heat for 1 hour or more, and many plastics are harmful at that temperature. Since it generates a large amount of decomposed gas, the gas treatment becomes a problem again. According to the moist heat sterilization method using high-pressure steam, sterilization is said to be completed when exposed to the steam at 121 ° C. for 20 minutes, for example, and at that temperature, plastic used as a medical instrument is stable, so there is no problem of gas treatment. However, infectious medical waste may include syringe barrels with blood, artificial dialysis equipment,
There are many pipe-like or tube-like things with closed end faces and complicated shapes such as blood piping systems, and in such medical waste, high-pressure steam cannot reach its inner surface,
It is hard to say that sterilization by wet heat is completed even if the above temperature and time are taken.

In the sterilization method using a chemical solution, the chemical solution used is harmful to the human body and may cause secondary contamination in the handling of the chemical solution or the treatment of the waste chemical solution after use, which is costly for safety measures and waste solution treatment. However, as in the case of using high-pressure steam, the chemical solution does not reach the inner surface of the pipe or tubular waste, and safe sterilization is difficult.

The present invention is intended to solve the problem of in-hospital treatment of infectious medical waste, and an object of the present invention is to sterilize medical waste at a relatively low temperature in a short time and reliably. In addition, the present invention provides a method and an apparatus that can be used for volume reduction treatment and are particularly suitable for in-hospital treatment.

[0012]

The method for treating medical waste according to the present invention comprises crushing the waste in a closed container,
Next, the air in the container is exhausted to the outside, and the exhausted air is sterilized or sterilized before being released to the atmosphere.
By sterilizing the waste that has become fragments and the inner wall of the container and the structure inside the container that have been in contact with it by filling the inside of the container with high-pressure steam at 0 ° C or more and 150 ° C or less for 10 minutes or more,
The method is characterized by taking one cycle of processing steps including the above steps in this order.

In this method, the temperature of the high-pressure steam used is set to 110 ° C. or higher because it takes a long time for the treatment to obtain a sufficient sterilizing effect at a temperature lower than that, which is not practical. Further, the temperature is set to 150 ° C. or less because the pressure resistance required for the container is too large to obtain the steam having a temperature higher than that, so that the manufacturing cost of the container is too high. Further, at a temperature exceeding 150 ° C, some plastic medical waste may start to decompose, which may cause a problem of secondary pollution. That is the reason why it was limited to. Further, in the high-pressure steam sterilization method in this temperature range, sterilization is not sufficient unless the temperature is held for at least 10 minutes, so the time for filling the container with high-pressure steam was set to 10 minutes or more in the present invention.

In the method of the present invention, the crushing treatment and the high-pressure steam sterilization treatment are carried out in this order for the following reason, which is an important component of the present invention. That is, among medical treatment wastes, there are pipe cylinders or tube-shaped ones with closed ends or complicated shapes, such as syringe cylinders, artificial dialysis instruments, blood piping systems, etc. with blood adhered to the inner surface. However, even if high-pressure steam sterilization is carried out, steam cannot reach the inner surfaces of them, and it is hard to say that sterilization by moist heat has been completed even if the above temperature and time are taken. This is because it is necessary to perform a crushing process and ensure that the blood adhered parts on the inner surfaces of the parts are also directly contacted with the high pressure steam.

Since the crushing process is carried out before the sterilization process, the inner surface of the container and the crushing blade in the container used for the crushing may have become infectious, and these parts were also crushed. Needs to be sterilized with waste. Therefore, in order to carry out high-pressure steam sterilization of these objects to be sterilized in a short time efficiently and without risk of scattering of infectious microorganisms, in the present invention, the waste fragments are not taken out from the crushed container, Sterilize in autoclave. Therefore, a crushing mechanism such as a crushing blade is incorporated in the container, and the container has a structure that can be hermetically sealed so as to fill the inside with high-pressure steam.

In order to introduce high-pressure steam into the container, it is necessary to exhaust the air inside the container. However, the exhausted air may contain infectious microorganisms scattered in the container by the crushing process. Therefore, in the present invention, the sterilization or sterilization process is performed before the exhaust air is released to the atmosphere. This sterilization treatment includes methods such as filtration, heating, and chemical oxidation, but is not limited to these methods.

On the other hand, the medical waste treatment apparatus according to the present invention is characterized by realizing the above-mentioned treatment method.
As a configuration of the device for that, as a pressure vessel having a crushing blade inside, which is provided with an opening portion that has a structure that can be hermetically closed and an opening that doubles as an outlet, and to introduce steam into the pressure vessel. And a pump for exhausting the air inside the pressure vessel, a mechanism for sterilizing or sterilizing the air before releasing the air to the atmosphere, and a mechanism additionally attached to these. To do. Here, the mechanism for introducing steam into the pressure vessel may be a mechanism having a heater for heating inside the pressure vessel, or may be connected by a pipe communicating with the pressure vessel. However, the mechanism may be provided with another pressure vessel dedicated to steam generation having a heating heater for steam generation inside, or a valve for introducing steam produced by an external boiler into the pressure vessel. It may be a mechanism provided with.

The present invention is provided with a pressure vessel having a structure capable of being sealed, and has a mechanism for crushing waste inside thereof.
Further, it should be apparent from the above description that a mechanism for introducing steam into the pressure vessel must be provided.
Further, a pump for exhausting the air in the container is also necessary for taking the above-mentioned treatment process, and the reason why a mechanism for sterilizing or sterilizing the exhaust is indispensable is also clear from the explanation of the treatment method.

By the way, as a mechanism for crushing waste, a mechanism having a mixer-like blade, a mechanism such as a ball mill, a mechanism for shearing between a uniaxial rotary blade and a fixed blade, and a biaxial rotary blade are used. A variety of shearing mechanisms are conceivable, and any of them can be selected in the device according to the present invention. The performance required for the crushing mechanism section of the device according to the present invention is that even infectious medical waste that is pipe-shaped or tube-shaped and has a closed end surface or a complicated shape is subjected to high-pressure steam sterilization treatment. Capable of crushing debris large enough to reach the inner surface of the steam, low noise, suitable for hospital treatment of medical waste, simple mechanism for crushing in a closed container It is suitable, the structure is robust and the equipment is easy to maintain, and the time required to complete crushing is short.

[0020]

According to the method and apparatus of the present invention, since the high-pressure steam sterilization method is adopted, it is possible to surely sterilize infectious medical waste in a short time at a relatively low temperature. Also, there is no concern about secondary pollution due to the decomposition gas of plastics, which are often contained in medical waste. In addition, since the crushing process of the input waste is before the high-pressure steam sterilization process, even if it is a pipe-shaped or tube-shaped waste with a closed end or a complicated waste, the high-pressure steam sterilization process At times, it is possible to carry out a reliable crushing process so that the steam reaches the inner surfaces of them sufficiently, and there is also an effect of volume reduction due to the crushing.

Furthermore, since the exhaust air accompanying degassing of the container after the crushing process for introducing the high-pressure steam into the container is opened to the atmosphere through the sterilization or sterilization mechanism, the infectiousness scattered in the container by the crushing. Will not be released into the atmosphere and cause secondary pollution.

Since crushing of infectious medical waste and steam sterilization by the method and apparatus of the present invention are performed in the same container,
The inner wall of the container and the structure inside the container that may become infectious as a result of touching infectious medical waste are sterilized together with the crushed waste, and the infectious microorganisms when the container is opened after treatment are sterilized. There is no scattering problem and it is safe to touch inside the container. Further, by using the same container, the treatment process and the apparatus are simplified, and the equipment cost and the treatment cost are reduced.

After the treatment of the infectious waste is completed by the method and apparatus of the present invention, the debris, the inner surface of the container, the structure in the container, and the water remaining in the container are removed. Both are sterilized. Thus, the waste debris removed is no longer infectious and can be treated as normal industrial waste. Therefore, even if the final treatment is outsourced to a waste treatment company, the treatment cost will be much lower than that for infectious waste, and the medical activity cost will be reduced. There is no possibility that infectious waste will be scattered due to the accident in Japan.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows an embodiment of a medical waste treatment apparatus according to the present invention. An example of the configuration of the medical waste treatment apparatus and an example of the medical waste treatment method according to the present invention will be described below with reference to this drawing.

[0025]

Example 1 Waste discharged from medical activities is introduced into the container 1 through an inlet 2 which is one of the openings of the container 1 made to withstand the pressure of high-pressure steam. The container 1 is also provided with a discharge port 3 which is another opening, and each opening has a structure capable of maintaining airtightness even if high-pressure steam is introduced into the container 1. The thrown waste is guided to the hopper 4 in the container 1 and is deposited on the rotary blade 5 for biaxial rotary shearing and crushing which is also installed in the container 1. After that, when the input port 2 is closed to prevent the waste from scattering outside the container 1 and the rotary blade 5 is rotated by a prime mover outside the container 1 not shown in the figure, the input waste is The crushed pieces 6 are accumulated on the saucer 7 placed on the saucer stand 8.

Here, the biaxial rotary shearing and crushing mechanism means that the blades for shearing and crushing are provided on the surfaces of two rollers having rotating shafts that are parallel or substantially parallel to each other, and the blades of both rollers that mesh with each other while rotating. Although it is a mechanism for shearing or crushing an object to be crushed between, the mechanism of this crushing unit in the device according to the present invention is not limited to the biaxial shearing crushing mechanism. Further, the receiving tray 7 and the receiving tray base 8 are both made of punching metal (perforated plate) in order to facilitate passage of high-pressure steam, but punching metal is one embodiment, and this is not always the case. It is not limited.

Next, the pump 9 installed outside the container 1 and connected to the container 1 by a pipe is operated, and the container 1
Aspirate the air inside. At this time, the opening and closing of the valve 10 arranged as necessary on the piping path is performed according to the purpose. Since the opening and closing of the valve 10 as necessary is the same in the following process steps, the description thereof will be omitted below. Since the sucked air is released to the atmosphere through the sterilization filter 11 installed on the piping path, even if the air in the container 1 contains infectious microorganisms due to crushing, it is released to the atmosphere. Will not cause secondary pollution.

Although the sterilization filter 11 is used here, as described above, various methods such as filtration, heating and chemical oxidation can be used for the sterilization or sterilization treatment here.
It is not limited to the sterilization filter. The deodorizer 12 is, for example, a deodorizing device using an activated carbon adsorption method,
The installation on the way of the pipe is optional, and if the gas sucked from the container 1 has an odor before or after the high-pressure steam sterilization process, install it and deodorize it before releasing the exhaust gas to the atmosphere. . By replacing the sterilization filter 11 with a sterilizer by heating, for example, sterilization and deodorization of the air passing therethrough can be performed at the same time.

Subsequently, the heater 14 heats the water 14 in the container 1 which is introduced from an external water supply source (not shown in the figure) and whose water level is adjusted by the level controller 13.
The container is filled with high-pressure steam by heating by 5, and the contents and inner wall of the container 1 are completely sterilized after, for example, 20 minutes at 121 ° C. put it here,
The temperature inside the container 1 is controlled by the temperature controller 16.

After the steam sterilization treatment is completed, water is jetted from the nozzle 17 installed in the container 1 to cool the container 1 and its contents, and the outside air is introduced through the air filter 18 to enlarge the inside of the container 1. Atmospheric pressure is maintained, the outlet 3 is opened, the tray 7 is taken out, and the waste fragments 6 that have been sterilized are discharged, and the water 14 in the container 1 is also discharged through a pipe. The container 1 is naturally constructed to withstand the pressure of high-pressure steam, but a safety valve 19 is provided so as to cope with an abnormal rise in pressure.

In the apparatus of this embodiment, the above series of steps constitutes one cycle of processing steps. In this embodiment, as a mechanism for introducing steam into the pressure vessel 1, a mechanism having a heater 15 for heating therein is adopted. However, the mechanism for introducing steam is not limited to this, and as shown in FIG. 2, the steam generation is connected to the pressure vessel 1 by a pipe and has a heater 15 for generating steam inside. The mechanism may be provided with another dedicated pressure vessel 20, or as shown in FIG. 3, the mechanism may be provided with a valve 10 or the like for introducing steam produced by an external boiler into the pressure vessel 1. Good. Further, an embodiment carried out for the purpose of verifying whether or not sterilization, which is the maximum purpose of the treatment of infectious medical waste, is properly performed by the medical waste treatment method and apparatus according to the present invention will be described below. .

[0032]

Example 2 In this example, cell spores were encapsulated in a dialyzer used for artificial dialysis in patients with renal failure,
20 lots were treated as 1 lot, and 3 lots were processed by using the apparatus and method described in the above embodiment. In each lot, one cycle of treatment process including a process of filling the container 1 with high-pressure steam at the following temperature for each time was carried out. Lot number 1 2 3 Temperature 115 ° C 121 ° C 126 ° C Time 30 minutes 20 minutes 15 minutes

The determination of sterilization after the treatment was carried out according to the Japanese Pharmacopoeia sterility test method using a thioglycolic acid medium at 37 ° C.
After culturing for one day, it was judged by the turbidity of the medium. As a result, in all of the three lots, no bacteria were detected in the dialyzer debris, the discharged air and the water. Therefore, the medical waste treatment method and device according to the present invention can perform an appropriate treatment even for medical waste having a pipe-like end face with a closed end face and infectious blood adhering thereto as in a dialyzer. It was confirmed that it was possible. The volume of the dialyzer after this treatment was about one half of that before treatment.

[0034]

As described above, according to the method and apparatus of the present invention, an inexpensive treatment facility that can install infectious medical waste discharged from a medical institution in a hospital without transporting it to another place is used. As a result, non-infectious industrial waste can be surely sterilized and reduced in volume at a relatively low temperature in a short time. There is no concern about secondary pollution due to exhaust of the treatment, and the treatment cost is low.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of a medical waste treatment device of the present invention.

FIG. 2 is a schematic diagram in the case where a mechanism for introducing steam into a pressure vessel is connected with a pipe communicating with the pressure vessel and is provided with another pressure vessel having a heater for generating steam therein. Is.

FIG. 3 is a schematic diagram when the mechanism for introducing steam into the pressure vessel is one for introducing steam produced by an external boiler.

[Explanation of symbols]

 1 Container 2 Input Port 3 Discharge Port 4 Hopper 5 Rotating Blade 6 Fragment 7 Saucepan 8 Saucepan Stand 9 Pump 10 Valve 11 Sterilization Filter 12 Deodorizer 13 Level Controller 14 Water 15 Heater 16 Temperature Controller 17 Nozzle 18 Air Filter 19 Safety Valve 20 Pressure vessel for steam generation

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahiro Dono, 1-30 Oyama-cho, Sagamihara-shi, Kanagawa Inside the Sagamihara Plant of Nippon Kinzoku Kogyo Co., Ltd. (72) Kazutaka Fujihira, 1-30 Oyama-machi, Sagamihara-shi, Kanagawa No. Japan Metal Industry Co., Ltd. Sagamihara Factory (72) Inventor Takashi Nakamura 2-1-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Japan Metal Industry Co., Ltd. 86-2, Nishimae-Nitta (72) Inventor Toshiro Asaoka, Inuyama City, Aichi Prefecture, Hashizume, Aichi Prefecture 46 (72) Inventor Akio Oya 1-22, Kirito-cho, Atsuta-ku, Nagoya City, Aichi Prefecture

Claims (5)

[Claims] 1. Crushing waste in a closed container,
Next, the air in the container is exhausted to the outside, and the exhausted air is sterilized or sterilized before being released to the atmosphere.
By sterilizing the waste that has become fragments and the inner wall of the container and the structure inside the container that have been in contact with it by filling the inside of the container with high-pressure steam at 0 ° C or more and 150 ° C or less for 10 minutes or more,
A method for treating medical waste, characterized by comprising a cycle of treatment steps including the above steps in this order. 2. A pressure vessel having an inlet and an outlet having a structure capable of being hermetically closed, or an opening serving as both of them, and having a crushing blade inside, and a mechanism for introducing steam into the pressure vessel. And a pump for exhausting the air inside the pressure vessel, a mechanism for sterilizing or sterilizing the air before releasing the air to the atmosphere, and a mechanism incidental thereto. Waste treatment equipment. 3. A pressure vessel having an inlet and an outlet having a structure capable of being hermetically closed, or an opening serving as both of them, and having a blade for crushing and a heater for generating steam therein, and the inside of the pressure vessel. An apparatus for treating medical waste, comprising a pump for exhausting air, a mechanism for sterilizing or sterilizing the air before releasing the air to the atmosphere, and a mechanism additionally associated therewith. 4. A pressure vessel having a hermetically-sealing inlet and outlet, or an opening serving as both of them, and having a crushing blade inside, and a pressure vessel and a pipe communicating with the pressure vessel. Other pressure vessels having a heater for generating steam inside, a pump for exhausting the air inside the pressure vessels, a mechanism for sterilizing or sterilizing the air before releasing the air to the atmosphere, and A medical waste treatment device comprising a mechanism associated with the above. 5. A pressure vessel provided with an opening and a discharge port having a structure capable of being hermetically closed, or an opening serving as both of them, and having a crushing blade inside, and a pressure vessel made of an external boiler. It consists of a mechanism for introducing steam, a pump for exhausting the air inside the pressure vessel, a mechanism for sterilizing or sterilizing the air before releasing the air to the atmosphere, and a mechanism incidental to these. An apparatus for treating medical waste characterized by: