JP2002059119A - Method and device for disposing of medical waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device capable of efficiently and surely disposing of medial waste by using supercritical water. SOLUTION: The medical waste 11 is introduced into a pre-pressurizing chamber 20, the pre-pressurized chamber 20 is pressurized with water, the medical waste is transferred to a treating chamber 30, in which the supercritical water region 34 is continuously formed, is kept for a prescribed time to be decomposed, the residue of the medical waste 11 is transferred with water to a previously pressurized evacuating chamber 40, the evacuating chamber 40 is evacuated and the residue of the medical waste is discharged from the evacuated chamber 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating medical waste discharged from a hospital or the like.

[0002]

2. Description of the Related Art Medical waste discharged from medical facilities such as hospitals, clinics, sanitary laboratories, medical research institutions, etc.
Since it contains waste that can or may be infected by humans, such as used injection needles, scalpels, and gauze, it has conventionally been separated according to its type and properties, or placed in a plastic bag or the like without separation. After being collected, incineration is performed inside or outside the facility using an incinerator. By incineration, the infectious waste is sterilized and made harmless, and at the same time, the generation of offensive odor due to the waste is prevented.

However, in the conventional incinerator, uneven incineration of waste is apt to occur, and as a result, the combustion becomes incomplete and sterilization and harmlessness of the waste cannot be achieved. There were problems such as generation of gas and dioxin.

Although some measures such as using activated carbon to remove dioxins and odors, maintaining the incineration temperature at a high temperature, and performing sterilization before incineration, some measures have been taken. In addition, there is a problem that the processing efficiency is deteriorated when sterilization and incineration are performed. Moreover, even with such measures, it was impossible to completely prevent the emission of harmful substances to the outside.

Under these circumstances, a method has recently been devised for oxidatively decomposing medical waste in supercritical water in order to solve the above-mentioned drawbacks of the conventional incineration treatment technology.

That is, the method comprises mixing medical waste with water, freezing it and crushing it into a slurry,
After freezing and crushing medical waste, water is added and slurried, and this is oxidatively decomposed in a reaction vessel using supercritical water as a reaction solvent, and it is said that medical waste can be rapidly and completely decomposed. It has features (strictly speaking, metals and glasses are not decomposed and remain as residues).

However, the conventional processing technology using supercritical water uses a so-called batch-type reaction vessel or a vessel-type reactor as a reaction vessel, and is not always satisfactory in terms of efficiency and reliability. Did not. In addition, there is a problem that it is necessary to pulverize waste before processing.

[0008]

As described above, a method of decomposing medical waste using supercritical water has recently been devised. However, it is inefficient, lacks reliability, and requires a pre-processing method. There are problems such as the necessity of crushing waste, and the actual situation is that it has not yet been put to practical use.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to efficiently and reliably treat medical waste by using supercritical water. It is an object of the present invention to provide a method and an apparatus that do not require grinding of an object.

[0010]

According to a first aspect of the present invention, there is provided a method for treating medical waste using supercritical water, wherein the medical waste is treated using supercritical water. The waste is introduced into a precompression chamber, the precompression chamber is pressurized with water, and the medical waste is transferred to a treatment chamber in which a supercritical water region is continuously formed, held for a required time, and subjected to decomposition treatment, Transfer the decomposition residue of medical waste to a decompression chamber pre-pressurized by water, decompress the decompression chamber,
Discharging a decomposed residue of the medical waste from the decompression chamber.

According to a second aspect of the present invention, there is provided a method for treating medical waste, wherein the medical waste is accommodated in an airtight container which is decomposed or dissolved by supercritical water to become water permeable. And is introduced into the preload chamber.

According to a third aspect of the present invention, in the method for treating medical waste, the closed container has a decomposition residue receiving portion formed of a material that is not decomposed by supercritical water to receive the decomposition residue. It is characterized by the following.

[0013] In order to achieve the above object, the present invention is directed to claim 4.
The medical waste treatment apparatus according to the invention described in (1) is an apparatus for treating medical waste using supercritical water, wherein an introduction port for introducing the medical waste is opened at an upper end and the medical waste is disposed at a lower end. A preload chamber with an open outlet for discharging waste, and an upper end connected to the outlet of the preload chamber, opening an inlet for introducing the medical waste discharged from the outlet, At the lower end, a processing chamber having an opening for discharging the medical waste processed material, and at the upper end, connected to the discharging port of the processing chamber, the medical waste processed material discharged from the discharging port. A decompression chamber having an opening for introduction, an opening for discharging the treated material of the medical waste at the lower end, and a port for selectively opening and closing the respective inlets and the respective outlets. Opening and closing means for pressurizing the preload chamber with water Precompression chamber pressurizing means, supercritical water region forming means for continuously forming a supercritical water region in the treatment chamber, and decompression chamber pressurizing means for pressurizing the decompression chamber with water. It is characterized by the following.

The supercritical water referred to here is supercritical water in a strict sense, that is, a critical temperature of 374 ° C. and a critical pressure of 22.
It does not mean only supercritical water exceeding 1 MPa, but includes so-called subcritical water.

In the method and apparatus for treating medical waste according to the present invention, the medical waste is brought into contact with supercritical water in a treatment chamber to be decomposed. The introduction of medical waste or its decomposed residues into the treatment chamber and the discharge from the treatment chamber are pre-pressurized and depressurized intermittently when medical waste is introduced or its decomposed residues are discharged. This is performed through a chamber and a decompression chamber. Therefore, a supercritical water region is always formed and maintained in the treatment chamber, and medical waste can be treated continuously and reliably. As a result, the processing efficiency and reliability can be greatly improved as compared with the conventional method. In addition, the medical waste may be introduced into the preload chamber as it is, and therefore does not need to be crushed prior to treatment as in the conventional method.

In particular, as described in claim 2, the medical waste is housed in an airtight container that is decomposed or dissolved by supercritical water so as to be water-permeable, and is introduced into the preload chamber. In the case of, the hermeticity is maintained before the treatment, preventing infection and contamination by medical wastes of workers and working environment, while in the treatment process, it is decomposed by supercritical water and water permeable Therefore, the treatment of medical waste with supercritical water is not hindered.

Further, when the closed container has a decomposition residue receiving portion formed of a material which is not decomposed by supercritical water in order to receive the decomposition residue, the medical device may be configured as a medical device. Decomposition residues of waste can be easily and reliably discharged from the processing chamber and the decompression chamber, and there is no possibility that decomposition residues remain in the processing chamber or the like and hinder subsequent processing. In addition, handling after discharge becomes easy.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of a medical waste treatment apparatus according to the present invention.

In FIG. 1, reference numeral 10 denotes a cylindrical processing tower. The processing tower 10 has, in order from the top, inlets 21, 31, for introducing the medical waste 11 or its decomposition residue into the upper end thereof. 41 and medical waste 1 at the lower end
1 or an outlet 22 for discharging the decomposition residue thereof,
A precompression chamber 20, a processing chamber 30, and a decompression chamber 40 having openings 32 and 42 are provided. The outlet 22 of the preload chamber 20 and the inlet 31 of the processing chamber 30, and the outlet 22 of the processing chamber 30 and the inlet 41 of the decompression chamber 40 are common valves 51 and 52, respectively.
And an inlet 21 of the preload chamber 20;
The discharge port 42 of the decompression chamber 40 also has valves 51, 5 respectively.
2 are connected. A receiver 50 for receiving the decomposition residue of the medical waste 11 discharged from the discharge port 42 of the decompression chamber 40 is provided below the processing tower 10.

The processing chamber 30 is a processing chamber using supercritical water. The processing chamber 30 is vertically divided into approximately three equal parts, and a preheating region 33, a supercritical water region 34, and a cooling region 35 are formed in this order from the top. ing. That is, a heater 36 is disposed below the preheating region 33 and on the outer periphery of the supercritical water region 34, and a cooling pipe 37 is provided on the outer periphery of the cooling region 35. The cooling pipe 37 is connected to the processing chamber 30.
And a part of a pipe 60 for supplying pure water into the inside. The pure water passes through a cooling pipe 37 by a pump 62 from a pure water tank 61 containing the pure water, and is substantially in the preheating region 33. The water is supplied into the processing chamber 30 through a pure water supply port opened at an intermediate portion. Note that a preheater 38 for preheating the pure water is provided near the pure water supply port of the pipe 60.

In the lower part of the processing chamber 30, a processing chamber 30 is provided.
A pipe 63 for discharging heated and pressurized pure water, gas and liquid generated by the processing, and the like is connected. That is, the other end of the pipe 63 is connected to the gas-liquid separator 65 via the cooler 64, and the heated and pressurized water discharged from the processing chamber 30 is cooled by the cooler 64 and condensed. Then, the gas component and the liquid component are separated by the gas-liquid separator 65, and are respectively discharged or collected to the outside. In the figure, 66 is a pressure reducing valve.

The preload chamber 20 and the decompression chamber 40 are provided in the processing chamber 3
0, the medical waste 11 is introduced.
When the decomposition residue is discharged, the internal pressure is maintained, and the internal pressure is increased and reduced by pure water having a low temperature of normal temperature to about 40 ° C. That is, pipes 69a and 69b for supplying pure water from a pure water tank 67 containing pure water by a pump 68, and a pressure reducing valve 70a for discharging pure water are provided in the preload chamber 20 and the decompression chamber 40. , 70b are connected to pipes 71a, 71b. The preload chamber 20 is also supplied with pure water from a branch pipe 72 branched from the pipe 60.

Further, in this example, three regions constituting the preload chamber 20 and the processing chamber 30 as described above are further provided.
That is, the preheating area 33, the supercritical water area 34, the cooling area 35, and the decompression chamber 40 are provided with holding means 73, 74 for holding the medical waste 11 or its decomposition residue for a required time in those chambers or areas. 75, 76, and 77 are provided. Among them, the preloading chamber 20, the cooling area 35 of the processing chamber 30, and the holding means 73, 76, 77 located in the decompression chamber 40 are used to transfer the medical waste 11 or its decomposition residue to the valves 51, 52, 54. It also has the role of preventing its function from being impaired by direct contact.

Next, a method for continuously treating medical waste 11 with supercritical water using the above apparatus will be described.

First, the valve 53 connected to the inlet 21 of the preload chamber 20 is opened, the other valves 51, 52 and 54 are closed, and the processing chamber 30 and the decompression chamber 40 are closed. Next, while the heater 36 is energized, the pump 62
To supply the pure water heated by the preheater 38 from the pure water tank 61 to the processing chamber 30, and into the processing chamber 30,
A preheating region 33, a supercritical water region 34, and a cooling region 35 are formed. In addition, the pump 68 is started, and the pure water tank 6 is started.
From 7, pure water at a low temperature of about normal temperature to about 40 ° C. is supplied to increase the internal pressure of the decompression chamber 40 to the same pressure as the internal pressure of the processing chamber 30.

In this state, the medical waste 11 is stored in the preload chamber 20.
Input. At this time, the preload chamber 20 is at normal temperature and normal pressure. The inserted medical waste 11 is held by the holding means 73 at a position in the preload chamber 20 that is separated from the valve 51.

After the medical waste 11 has been charged, the valve 53 is closed, the pump 68 is started, and pure water 21 at a low temperature of normal temperature to about 40 ° C. is supplied from the pure water tank 67 to increase the internal pressure of the preload chamber 20. Let it. When the internal pressure of the preload chamber 20 becomes substantially the same as the internal pressure of the processing chamber 30, the valve 51 is opened and the holding by the holding means 73 is released.

The medical waste 11 falls under its own weight from the preloading chamber 20 into the processing chamber 30 and is held by the holding means 74 in the preheating area 3.
Once held in 3 and preheated. Thereafter, the holding means 7
When the holding by the medical waste 11 is released, the medical waste 11 falls into the supercritical water area 34 and is held for a required time by the holding means 75, and the metal and glass such as an injection needle contained in the medical waste 11 are contained by the supercritical water. Organic substances (resins, blood, pathogens, etc.) except for those are decomposed. Thereafter, the holding means 75
As a result, the residue of the medical waste 11 such as metal and glass remaining without being decomposed further falls into the cooling area 35 and is held by the medical waste holding means 76. When the valve 52 is opened and the holding by the holding means 76 is released when the temperature is cooled to a temperature close to the normal temperature in the cooling area 35, the residue of the medical waste 11 is pre-pressurized to the same pressure as the internal pressure of the processing chamber 30. It falls under its own weight into the reduced pressure chamber 40, and is held by the holding means 77.

When the residue of the medical waste 11 falls into the decompression chamber 40 in this way, the valve 52 is closed,
The pure water in the decompression chamber 40 is discharged to reduce the pressure. When the internal pressure of the decompression chamber becomes normal pressure, the valve 54 is opened and the holding means 77
Is released, the residue of the medical waste 11 falls from the decompression chamber 40 into the receiver 50 by its own weight and is collected.

On the other hand, in the preload chamber 20, after the medical waste 11 falls into the processing chamber 30, the valve 51 is closed and the pressure is reduced. And when the internal pressure is almost normal pressure,
The valve 53 is opened, the next medical waste 11 is charged,
The above operation is repeated.

In this way, the medical waste 11 is put into the preload chamber 20 one after another, and the above operation is repeated.
Medical waste is treated continuously.

During this time, the decomposition products of the medical waste 11 generated in the processing chamber 30 are discharged from the processing chamber 30 through the pipe 63 together with the pure water introduced into the processing chamber 30, and then are cooled by the cooler 64. Cooled, depressurized, gas-liquid separator 65
Is separated into gas and liquid.

In such an apparatus and method, the medical waste 11 can be charged and discharged while maintaining the temperature and the internal pressure in the processing chamber 30, that is, while maintaining the processing conditions of the medical waste 11. Medical waste 1
1 can be processed continuously, thereby
As compared with the conventional method, the treatment efficiency is greatly improved, and a large amount of medical waste can be treated in a short time. Also,
The medical waste 11 may be introduced into the preload chamber 20 as it is, and therefore does not need to be crushed prior to treatment as in the conventional method.

Further, since the preheating region 33 is provided in the processing chamber 30, it is possible to avoid a rapid expansion of water generated when the medical waste 11 at normal temperature is directly introduced into the supercritical water region 34. The safety of the device can be increased.

Further, since the cooling area 35 is provided in the processing chamber 30, it is possible to prevent the sealing performance of the valve 52 from being lowered, and to enhance the reliability of the apparatus.
That is, when such a cooling region 35 is not provided, the residue of the medical waste 11 having an extremely high temperature, which is a supercritical temperature, passes through the valve 52, and the valve 5
2 may impair the sealing performance, whereas if a cooling area is provided, the cooled medical waste 11
Since the residue passes through, the valve 52 is prevented from being damaged or its performance is reduced.

In the present invention, the medical waste 11
Is previously collected in a sealed container having a size and a shape that can smoothly pass through each chamber in the treatment tower 10 and configured to be decomposed or dissolved by supercritical water to become water permeable, Into the preload chamber 20.
Such a container is kept hermetically sealed before the treatment and can prevent infection and contamination by medical wastes of workers and working environment, while being charged into the treatment tower 10 and transferred to the treatment chamber 30. Thereafter, the medical waste 11 is decomposed by the supercritical water and becomes water-permeable, so that the treatment of the medical waste 11 with the supercritical water is not hindered.

Further, it is more preferable that the closed container is capable of receiving a metal, glass, or the like which remains as a residue without being decomposed by supercritical water. This is because not only the decomposition residue such as metal can be easily and reliably discharged from the processing chamber 30 and the decompression chamber 40, but also the handling after the discharge becomes easy. If the residue remains in the processing chamber 30 or the like, there is a possibility that the subsequent processing will be hindered.

More specifically, for example, as shown in FIG. 3, a metal such as polyethylene, polypropylene, polyethylene terephthalate or the like, as shown in FIG. A container provided with a sub-container 103 made of a mesh, or a container having such a sub-container 103 buried in a container main body 101; Plastics such as polyethylene, polypropylene and polyethylene terephthalate, and those formed with inorganic salts such as sodium chloride and potassium chloride. The sub-container 103 may be made of metal or ceramic provided with a large number of through-holes or fine slits. The plastic container body 10
1 has a multi-layered structure made of different types of plastics, or a diagonally stuck string of carbon fiber, nylon fiber, polyester fiber, etc. with good slipperiness on the inner surface to make it less susceptible to damage by injection needles or scalpels. Or
The side wall may be corrugated.

In the present invention, the valve 5
1, 52, 53, 54, heater 36, pump 62,
Control means for operating the holding means 73, 74, 75, 76, 77 as described above may be provided. By providing such a control means, the processing operation becomes easy, and the human burden of the operation can be reduced, which is more advantageous.

Further, since the decomposition conditions of the medical waste 11 are different depending on the type and amount thereof, a confirmation means for confirming the decomposition state of the medical waste 11 is provided in the supercritical water region 34 of the treatment chamber 30. Alternatively, a monitoring window may be provided so that the disassembly state can be visually checked. By providing such a checking means, the medical waste 11 can be reliably decomposed regardless of its type and amount, and the reliability of the treatment can be improved.

In the present invention, if necessary,
A catalyst for promoting decomposition by supercritical water, such as cobalt molybdenum tetroxide (CoMoO ₄ ), may be introduced into the supercritical water region 34 in the processing chamber 30. The introduction may be performed directly into the processing chamber 30, but it is more convenient if the above-described closed container is used.

In the example described above, a valve is used as the opening / closing means. However, it goes without saying that other known opening / closing means having a high sealing property can be used in place of the valve.

[0044]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example A 2.5 ml disposable syringe of medical waste (material: polypropylene) was treated using the treatment apparatus shown in FIG.

First, 0.2 m shown in FIG. 3 is placed in a cylindrical PET container (capacity: about 150 ml, wall thickness: 3 mm) 101 shown in FIG.
An m-mesh stainless steel container 103 was accommodated therein, and the two syringes were placed therein. The container was sealed with a PET lid 102, and then put into the preload chamber 20. After the charging, the valve 53 at the upper part of the preload chamber was closed, and the internal pressure in the preload chamber 20 was increased with pure water at normal temperature. When the internal pressure reaches 40 MPa, the preload chamber 2
0 and the processing chamber 30 by opening the valve 51,
The sample was dropped by its own weight to the preheating region 33 of the processing chamber 30 in which the supercritical water region 34 of 40 ° C. and 40 MPa was formed, and held for 10 minutes.

Next, it is dropped by its own weight into the supercritical water region 34.
After holding for 10 minutes, it was confirmed from the monitoring window provided on the side wall of the supercritical water area 34 that only the metal container 103 containing the injection needle remained, dropped into the cooling area 35 and held for 10 minutes.
After that, the valve 52 between the processing chamber 30 and the decompression chamber 40 is opened, and after its own weight is dropped into the decompression chamber 40 whose internal pressure has been increased to 40 MPa with pure water at normal temperature, the valve 52 is closed,
The internal pressure in the decompression chamber 40 was reduced. When the internal pressure reached normal pressure, the valve 54 below the decompression chamber 40 was opened, and the metal container 103 containing the injection needle was collected in the receiver 50.

[0048]

As described above, according to the present invention,
Using supercritical water, medical waste can be efficiently and reliably treated, and the step of pulverizing the medical waste during treatment can be omitted.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing an example of a medical waste treatment apparatus according to the present invention.

FIG. 2 is a perspective view showing an example of a closed container used in the present invention.

FIG. 3 is a perspective view showing an example of a sub-container used in the present invention.

[Explanation of symbols]

 11 Medical waste 20 Preload chamber 21, 31, 41 Inlet 22, 32, 42 Outlet 30 Processing chamber 33 Preheating area 34 Ultra Critical water area 35 Cooling area 36 Heater 40 Decompression chamber 51, 52, 53, 54 Valves 61, 67 Pure water tank 62, 68 Pump 73 74, 75, 76, 77 Holding means 101 Container main body 102 Sealing lid 103 Sub-container

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kiyoji Furumura 20-1 Kitakanyama, Odaka-cho, Midori-ku, Nagoya-shi, Aichi Prefecture Inside the Electric Power Research Laboratory, Chubu Electric Power Co., Inc. 2-1, 1-1 Oda Sakae-ku, Showa Electric Wire & Cable Co., Ltd. (72) Inventor Hiroaki Morita 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture F-term in Showa Electric Wire & Cable Co., Ltd. 4D004 AA48 AB03 AB10 AC04 CA32 CA34 CA39 CA50 CB04 CB31 CB32 CC03 CC09 DA02 DA06 DA07 DA12

Claims (4)

[Claims] 1. A method of treating medical waste using supercritical water, comprising introducing the medical waste into a preload chamber, pressurizing the preload chamber with water, and converting the medical waste into a supercritical water region. Transfer to a treatment chamber that is formed continuously, decompose and hold for a required time, transfer the decomposition residue of the medical waste to a decompression chamber pre-pressurized with water, and decompress the decompression chamber, A method for treating medical waste, comprising a step of discharging a decomposition residue of the medical waste from the decompression chamber. 2. The medical waste is introduced into the precompression chamber by being housed in a sealed container configured to be decomposed or dissolved by supercritical water to become water permeable. The medical waste treatment method described in the above. 3. The treatment of medical waste according to claim 2, wherein the closed container has a decomposition residue receiving portion formed of a material that is not decomposed by supercritical water to receive the decomposition residue. Method. 4. An apparatus for treating medical waste using supercritical water, wherein an inlet for introducing the medical waste is opened at an upper end, and an outlet for discharging the medical waste is provided at a lower end. A preload chamber having an opening, an upper end connected to an outlet of the preload chamber, an inlet for introducing the medical waste discharged from the outlet being opened, and a processed material of the medical waste at a lower end. A treatment chamber having an opening for discharging the wastewater, an upper end connected to the discharge port of the processing chamber, and an opening for introducing the processed material of the medical waste discharged from the discharge opening. A pressure reducing chamber having an opening at the lower end for discharging the treated medical waste, an opening / closing means for selectively opening / closing each of the inlet and each of the outlets, and Pressurizing chamber pressurizing means for pressurizing by means of A supercritical water region forming means for continuously forming a supercritical water region in a scientific room, and a medical waste comprising: a decompression chamber pressurizing means for pressurizing the decompression chamber with water. Processing equipment.