JP6941452B2 - Dismantling and decontamination methods for workplaces where PCB contaminants are handled - Google Patents

Description

The present invention relates to a method of dismantling and decontaminating a workplace where contaminants contaminated with PCB are handled.

PCB (polychlorinated biphenyl) has been used as an insulating oil for electrical equipment such as capacitors and transformers in the past because it has excellent stability, nonflammability, and electrical insulation. It has become clear that it is toxic and its use is currently restricted.
Then, the use of the contaminants is regulated, and the contaminants contaminated with PCB (hereinafter, also referred to as "PCB contaminants") are recovered and a controlled area is provided as shown in Patent Document 1 below. Detoxification is done in the special facility.

By the way, the number of PCB pollutants to be treated has decreased due to the treatment of PCB pollutants for many years, and some of the facilities for detoxification treatment are completing their missions.
However, if a facility that has a workplace where PCB contaminants have been handled up to that point is dismantled as it is, it will be installed on the walls (side walls, floor walls, ceiling walls, etc.) of the workplace that have been exposed to the environment including PCBs. It will expose the installed object to the uncontrollable outside air.
In the workplaces that handle PCB contaminants as described above, the working environment is maintained by controlling the PCB concentration in the air below a certain level by ventilation, etc., but there is a risk that PCBs may adhere to unexpected locations. There is.
Therefore, if the workplace is inadvertently disassembled, the PCB may spread to the surrounding environment.
In addition, it is conceivable to continue to effectively use the above-mentioned workplace as a treatment workplace for harmful substances without dismantling it.
However, even in that case, if the PCB is attached to the wall surface or the like, a problem arises.

Japanese Unexamined Patent Publication No. 2003-035044

For the above reasons, it is desirable for a workplace where PCB contaminants have been handled to sufficiently reduce the amount of PCB adhering to the installation objects and wall surfaces in the workplace after completing its mission.
However, there are many areas in the workplace where PCBs are not attached at all or the amount of PCBs is at a level where there is no problem at all, and PCBs are reduced for walls and installations even when there is no need for decontamination. It is not preferable from the viewpoint of work efficiency to perform the treatment for the above.

That is, there is a demand for efficient decontamination of workplaces where PCB contaminants are handled.
However, a specific method for grasping the amount of PCB adhered to the wall surface of a work place or the like has not been sufficiently studied so far.
Therefore, the above requests have not yet been satisfied.
Therefore, in view of such a situation, it is an object of the present invention to provide a decontamination method for a workplace and a dismantling method thereof that satisfy the above requirements.

As a result of diligent studies by the present inventor in order to solve the above problems, it has been found that the PCB concentration in the air is relatively high in the vicinity of the portion where the PCB is attached as compared with the other portions.
Then, the present inventor can grasp the change in the PCB concentration in the air after ventilation by measuring the PCB concentration in the air in the workplace after ventilating the workplace, and specify the necessity of decontamination of the workplace. We have found that we can obtain it and have completed the present invention.

That is, in order to solve the above problems, the present invention is a method of dismantling a workplace in which contaminants contaminated with PCBs are handled, that is, a ventilation step for ventilating the workplace and air in the workplace after the ventilation step. Provided is a method of dismantling a workplace in which a concentration measuring step of measuring the PCB concentration in the workplace is carried out before the dismantling of the workplace.

Further, the present invention is a method for decontaminating a workplace in which a decontamination step for decontaminating a workplace in which contaminants contaminated with PCB is handled is carried out, and is a ventilation step for ventilating the workplace and the ventilation. Provided is a concentration measuring step of measuring the PCB concentration in the air in the workplace after the step, and a method of decontaminating the workplace, which is carried out before the decontamination step.

According to the present invention, since it is possible to grasp the state of contamination of the PCB in the workplace to be decontaminated, it is possible to prevent the work of removing the PCB from becoming inefficient.

Schematic three-view view (plan view (a), front view (b), side view (c)) showing an example of a workplace where contaminants contaminated with PCBs are handled. The schematic plan view which showed the state of the concentration measurement process. The schematic plan view which showed the state of the workplace (state of the division process) divided into a plurality by a partition. A schematic perspective view showing a specific example of a partition used for dividing a workplace. FIG. 6 is a schematic plan view showing a state in which the workplace is divided by the partition shown in FIG. Schematic plan view showing the state of the decontamination process for the wall surface. The schematic plan view which showed the state which the once divided area is further divided (the state of the re-dividing process). FIG. 6 is a schematic plan view showing a state (state of the decontamination process) in which decontamination by ventilation is performed on the finely divided areas shown in FIG. 7.

Embodiments of the present invention will be described below.
In the following, a case where the facility to be decontaminated has only a single workplace will be described as an example.
As shown in FIG. 1, the workplace 10 where decontamination is performed in the present embodiment includes a floor wall 11 having a horizontally long rectangular shape in a plan view, and a side wall 12 rising vertically from each of the four sides of the floor wall 11. A ceiling wall 13 arranged above the floor wall 11 is provided.
The shape of the ceiling wall 13 in a plan view is substantially the same as that of the floor wall 11.
The ceiling wall 13 and the floor wall 11 are arranged so that the wall surfaces are substantially parallel to each other and the contour shapes in a plan view are substantially the same.
That is, the work space 10 of the present embodiment has a rectangular parallelepiped-shaped work space in which six surfaces are defined by a floor wall 11, a ceiling wall 13, and four side walls 12a, 12b, 12c, and 12d, respectively.

Examples of PCB contaminants handled in the workplace 10 include capacitors and transformers containing insulating oil containing PCB.
The workshop 10 of the present embodiment is provided in a treatment facility for detoxifying PCB contaminants, and a treatment apparatus 20 for treating the contaminants is arranged in the central portion.
Specific examples of the processing apparatus 20 include, for example, a cutting machine for cutting PCB contaminants, a transporter for transferring PCB contaminants and their cut pieces, and cleaning for cleaning PCB contaminants and their cut pieces. Machines and the like can be mentioned.
The work place 10 is further provided with a ventilation device 30 for ventilating the inside of the work place.
As the ventilation device 30, for example, one configured to attract the outside air A into the field by treating the air in the work place to a state where it can be discharged to the outside of the system and performing exhaust E can be adopted.
The ventilation device 30 may form, for example, an air flow F (downward flow) from the ceiling wall 13 to the floor wall 11 by the attracted outside air A in the field.

The workplace 10 can be disassembled by carrying out the steps shown in (A) to (C) below, for example.

(A) Decontamination target identification process In the decontamination target identification process, the location in the workplace where the PCB is attached is specified, and the specific decontamination method to be adopted in the subsequent decontamination process is determined. ..
(B) Decontamination step In the decontamination step, decontamination is performed on the place where PCB adhesion is recognized in the decontamination target identification step, and the PCB adhesion amount is reduced to a level that is practically no problem. NS.
(C) Dismantling step In the dismantling step, a workplace that has been sufficiently decontaminated in the decontamination step is dismantled.

Workplaces usually have installations such as worktables, shelves, and equipment, and PCBs may be attached to these installations or the walls of the worksite.
In the present embodiment, the adhesion state of PCB is grasped based on the amount of PCB contained in the surrounding air (PCB concentration).
Here, the wall surface of the work place usually has a large area, and it is necessary to measure the PCB concentration at many places in order to grasp the adhesion state of PCB.
On the other hand, with respect to the above-mentioned installed object, it is usually possible to grasp the adhesion state of PCB by sampling air at one or two places in the vicinity.
However, while the wall surface of the workplace is relatively two-dimensional, the shape of the installed object is three-dimensional, and the PCB is not always attached only to the surface, but is attached to the inside. There may be.
Therefore, although it is easier to confirm the adhesion of PCBs on the installed object than on the wall surface, it is difficult to grasp in advance how much time and effort is required to reduce the amount of PCBs attached to the installed object.
On the other hand, it is relatively easy to reduce the amount of PCB attached to the wall surface if the PCB attached portion can be specified, but it is difficult to pinpoint the PCB attached portion.
Therefore, in the present embodiment, it is preferable to carry out the decontamination target specifying step and the decontamination step a plurality of times, and to alternately carry out the decontamination target specifying step and the decontamination step.
In this case, since the PCB concentration measuring step (concentration measuring step) is carried out in the decontamination target specifying step, the concentration measuring step is carried out before and after the decontamination step in the present embodiment.
That is, in the preferred embodiment as described above, the decontamination step is carried out a plurality of times while confirming the degree of decontamination by the concentration measuring step.
Then, in the present embodiment, it is preferable to measure and confirm the PCB concentration in the air in the vicinity of the installed object or the wall surface to confirm whether or not the amount of PCB adhered to the installed object or the wall surface is finally sufficiently reduced.
Therefore, in the present embodiment, it is possible to efficiently grasp the PCB contamination status of the workplace where the PCB contaminants are handled, and it is possible to efficiently evaluate the decontamination.

Next, a specific method of each of the above steps will be described.
(A _-1 ) Decontamination target identification process (first time)
When identifying the decontamination target, first, a step of measuring the PCB concentration in the air in the workplace (concentration measurement step) is carried out.
The concentration measuring step can be carried out by using one or more concentration measuring instruments capable of measuring the PCB concentration.
In the concentration measuring step, as shown in FIG. 2, a plurality of concentration measuring instruments DT1 and DT2 are used, and the concentration measuring instruments DT1 and DT2 are arranged vertically and horizontally so as to be arranged at equal intervals in the workplace, and the respective concentrations are arranged. It is preferable to simultaneously measure the PCB concentration with the measuring instruments DT1 and DT2.

The concentration measuring step may be carried out by one concentration measuring device instead of the above-mentioned preferable method.
In this case, the measurement is performed at a plurality of locations while sequentially changing the installation location of the concentration measuring device.
That is, in this case, in the concentration measurement step, the measurement is carried out at one place, the concentration measuring device is moved to another place after the measurement is completed, and the measurement is carried out again at another place after the movement. It will be carried out in a progressive manner.
Therefore, in this case, one measurement and another measurement are performed at different time zones.
As a specific embodiment of the concentration measuring step, it is usually more advantageous to operate a plurality of concentration measuring devices in parallel as described above than to reuse one such concentration measuring device. be.
That is, since it usually takes several hours or more to measure the PCB concentration in the air, if the location where the PCB is attached can be roughly identified and the number of measurements is small, one concentration measuring device is used. Although the turning method can be advantageous, it generally takes a considerable amount of time to complete the measurement.
Further, the method in the first stage is advantageous in that it can prevent the measurement environment such as room temperature from being significantly different depending on the measurement point as compared with the method in the second stage, and can exhibit high reliability in the relative comparison of the measurement results.

In the concentration measuring step, if PCB diffused in the air from a specific place in the work place is detected by a concentration measuring device installed in another place, it becomes difficult to make an accurate determination.
Therefore, when carrying out the concentration measurement step, it is preferable to ventilate the site (ventilation step) by operating the ventilation device 30 in advance.
The ventilation frequency in the ventilation step can be, for example, 1 to 10 times / h.
It is preferable that such ventilation in the workplace is continuously performed even after the concentration measurement step is started, and it is preferable that the ventilation is continued at least until the concentration measurement step is completed.

In the concentration measurement step, for example, the concentration measuring device DT1 arranged along the side wall 12 confirms the adhesion state of PCB on the wall surface, and the concentration measuring device DT2 arranged near the installation object such as the processing device 20 confirms the installation object. The state of PCB adhesion to the surface is confirmed.
The PCB concentration in the air should be obtained, for example, according to "3. POPs monitoring survey in the air" of "Part II Analysis Method" of the "Monitoring Survey Manual" published by the Environment and Safety Division, Environment and Health Department, Ministry of the Environment. Can be done.
Specifically, the PCB concentration in the air is sampled by a method of sucking the air to be measured through the collecting material for a certain period of time, and the amount of PCB collected by the collecting material is measured by gas chromatography / high. It can be determined by quantifying with a resolution mass spectrometer (GC / HRMS).
When a certain amount or more of PCB is attached to the wall surface of the work place 10, the concentration of PCB in the air in the vicinity increases due to the diffusion of PCB.
Therefore, in the process, it is possible to grasp how much PCB is attached to the surrounding wall surface by the amount of PCB collected by the collecting material.

The concentration measurement step may be carried out after moving the installation object.
That is, the concentration measuring step may be carried out after a plurality of installed objects are put together at one or two or more places in the workplace.
In this case, if the installation object provided near the wall is moved to the central portion of the hall, the concentration measuring device DT1 for checking the adhesion state of PCB on the wall surface can be arranged near the side wall 12.
Further, by collecting a plurality of installed objects, it is possible to check the adhesion state of PCB with one concentration measuring device DT2 for the plurality of installed objects.
In this case, although it is difficult to determine whether the PCB is attached to one of the installed objects or the other installed objects, if the decontamination process is continuously performed for these, these should be used. It has the effect of being able to decontaminate all at once.

The installation may be disassembled.
Even if the amount of PCB attached to the installed object is the same, the value of the PCB concentration in the air is lower when the PCB has entered the inside than when the PCB is attached to the surface of the installed object. Can be observed.
In addition, it is usually more difficult to remove PCBs in the decontamination process in an installed object in which PCBs have entered the inside than in the case where PCBs are attached to the surface.
Therefore, for installations that have PCBs inside, dismantling improves the detection sensitivity of the concentration measuring instrument and is expected to have the effect of efficiently removing PCBs in the decontamination process. can.

As described above, in the process of specifying the decontamination target, the adhesion state of PCB on the installed object or the wall surface is confirmed.
If it is clear that PCBs are attached to some of the installation objects or parts of the wall surface, or conversely, if it is clear that PCBs are not attached, it is necessary to measure the PCB concentration in the air in the vicinity of these. There is no.
In the present embodiment, as will be described later, a decontamination step for reducing the amount of PCB adhered to the wall surface or the installation object to which the PCB is attached is carried out, and the wall surface or the installation after the decontamination step is performed. Judgment (graduation judgment) is made as to whether or not sufficient decontamination has been performed on the object.
Therefore, if it is clear that PCBs are attached, the decontamination step may be performed without measuring the PCB concentration in the nearby air, and if it is clear that PCBs are not attached, the decontamination step is also performed. Instead, it may be the target of the graduation judgment.

Further, in the decontamination target specifying step, after grasping the PCB adhesion state as described above, a detailed investigation may be carried out for a part of the regions.
When the investigation target is a plurality of installation objects whose PCB adhesion amount has been collectively determined in the decontamination target identification step, these may be divided into two or more and the PCB adhesion status of each may be confirmed again.
When the target of the detailed investigation is a wall surface, a partitioning step may be performed in the workplace to divide the site, and the PCB concentration may be measured in a region separated from other regions by the dividing step.
By separating a part of the region from the other region in this way, it is possible to prevent a small amount of PCB diffused into the air from the PCB adhering to the wall surface or the like from diffusing to other regions. ..
Therefore, by providing the sorting step, it is possible to obtain more accurate information regarding the presence or absence of adhesion of the PCB to the wall surface in the region and the amount of adhesion thereof.

The narrower the area to be divided by providing a partition in the dividing process, the more accurate information can be obtained about the adhesion state of the PCB to the wall surface.
On the other hand, in order to reduce the number of divisions and simplify the division process, it is preferable that the area is wide.
Therefore, the region divided by segmentation step is preferably divided over the wall or ceiling so that 10 to 30 m ³ approximately as the volume by a partition.

The partition provided in the partitioning step may be provided so as to create a gap on the ceiling wall side or the floor wall side, but in order to prevent air replacement due to convection or the like with another adjacent region. Is preferably provided so as to be in contact with at least one of the floor wall side and the ceiling wall side, and particularly preferably is provided so as to be in contact with both the floor wall side and the ceiling wall side.
The partition can be formed by installing a counter with a resin sheet on a rectangular frame, or by suspending the resin sheet alone from the ceiling wall.

The sorting step can be carried out by, for example, the method shown in FIG.
That is, the dividing step can be carried out by a method of dividing the space in the work place into a plurality of regions 10a so that the arrangement state of the partitions 40 in the plan view is "lattice-like".
By re-performing the concentration measurement step for each region 10a divided in this way as a measurement target, it is possible to grasp in detail how much PCB is attached to which part of the workplace.
That is, in the present embodiment, a part of the divided plurality of regions 10a can be excluded from the decontamination target, or a part can be decontaminated by a simpler method than the other regions.

For the division as shown in FIG. 3, for example, as shown in FIG. 4, a plurality of members 40x having a “U-shaped” shape in a plan view are prepared, and the members 40x are as shown in FIG. It can be arranged and done.
By specifying the adhesion location of the PCB in a narrower range in this way, more efficient decontamination can be performed in the decontamination step.

(B _-1 ) Decontamination process (first time)
In the decontamination step, a process of reducing the amount of PCB adhered to the installed object or wall surface determined to be decontaminated in the decontamination target specific step is performed.
In the decontamination step, it is preferable that decontamination is performed by a method selected from a plurality of predetermined methods.
Moreover, it is preferable that the plurality of methods are predetermined methods according to the measurement result (high or low of the measured PCB concentration) in the concentration measuring step performed immediately before the decontamination step.
That is, in the present embodiment, "when the PCB concentration measured in the concentration measuring step is 0 (μg / Nm ³ ) or more and x (μg / Nm ³ ) or less, a decontamination method called" X "is adopted. When the PCB concentration exceeds x (μg / Nm ³ ) and is y (μg / Nm ³ ) or less, a decontamination method called “Y” is adopted, and the PCB concentration exceeds y (μg / Nm ³ ) and z ( It is preferable to predetermine that "a decontamination method called" Z "is adopted in the case of μg / Nm ³ ) or less", and to determine the method for decontaminating each region based on this prior agreement (however, : 0 <x <y <z).

Examples of the method for reducing the amount of PCB adhering to the object to be treated such as an installation object or a wall surface include a method of cleaning and removing the PCB and a method of evaporating and removing the PCB adhering to the object to be treated.
More specifically, as the method, for example, a plurality of methods such as the following can be mentioned.
-A method of replacing the air around the object to be treated with air having a PCB concentration lower than that of the air to evaporate and remove the PCB adhering to the object to be treated (simple ventilation method).
-While heating the object to be treated and promoting the diffusion of the attached PCB into the air, the air around the object to be treated is replaced with air having a PCB concentration lower than that of the air and adheres to the object to be treated. Method of evaporating and removing PCB (heat ventilation method)
-A method of cleaning the object to be treated with a cleaning agent to remove PCB adhering to the object to be treated (simple cleaning method)
-A method of cleaning the object to be treated while heating it to remove PCB adhering to the object to be treated (heat cleaning method).

When the installed object is to be treated in the decontamination step, it is preferable to evaporate and remove the PCB by a simple ventilation method or a heat ventilation method.
The method of evaporating and removing PCB is preferable in that it can be easily carried out as compared with the method of cleaning the object to be treated.
As a specific embodiment of the method, the installation object is covered with a covering member capable of covering the installation object in the field to be treated, and one area in which the installation object is arranged and another area in the workplace are arranged. A method of providing a partition with the covering member between the air and the air and supplying air having a PCB concentration lower than the PCB concentration of the air in the one region to the one region can be mentioned.
The covering member used in this method may be the one shown in FIG. 4, or may be a simple sheet (for example, a resin sheet, a rubber sheet, a cloth) or the like.
Further, as the air (air for reducing PCB) supplied into the region in order to reduce PCB, the PCB concentration ^{is preferably 1 μg / Nm 3} or less.

As the PCB reducing air, for example, it is preferable to use outside air, but if necessary, air outside the region or air inside the region in the workplace can also be used.
To explain this point in more detail, for example, when the PCB concentration around the region covered with the covering member is sufficiently lower than the air in the region (for example, when the PCB concentration is 1 μg / Nm ³ or less). If there is, this air can be supplied into the region and used as PCB reduction air.
At this time, it is necessary to exhaust the air containing the PCB from the region, but the exhaust may be discharged to another region in the field through a filter capable of capturing the PCB.
Exhaust gas after passing through the filter may be exhausted outdoors if the conditions are met.

The PCB reduction air may be generated using the air in the region as described above.
More specifically, for example, a ventilator having the filter is installed in or out of the region, and the ventilator is used to pass air in the region through the filter to reduce the PCB concentration. , The air after passing through the filter may be supplied to the region again to reduce the amount of PCB adhered to the object to be treated.

In these methods, it is preferable to heat the inside of the region in order to promote the evaporation of PCB from the object to be treated.
Examples of the heating method in the region include installing a heating device such as a heater in the region, or making the PCB reduction air higher than the air temperature in the region and supplying it into the region. Can be mentioned.
Among them, as a heating method of the region, a method of supplying PCB reducing air having a temperature higher than the temperature in the region (for example, 30 ° C. to 80 ° C., preferably 40 ° C. to 60 ° C.) into the region is used. It is preferable in that it is simple.

This decontamination step is preferably carried out while monitoring the PCB concentration of the air in the region in order to determine whether sufficient decontamination has been carried out.
Specifically, in the decontamination step, for example, a method of supplying air having a ^{PCB concentration of less than 1 μg / Nm 3} into the region and continuing ventilation until the ^{PCB concentration in the exhaust becomes less than 10 μg / Nm 3.} It is preferable to adopt.

On the other hand, in the cleaning and removal, a method of immersing the object to be treated in a bath containing a cleaning liquid, a method of steam cleaning or a method of spray cleaning can be adopted.

In the decontamination step, it is preferable to adopt a method by evaporation removal such as a simple ventilation method or a heat ventilation method even when the object to be treated is not an installed object but a side wall 12 or the like.
In these methods, a larger ventilation rate is advantageous in reducing the amount of PCB.
Therefore, even when decontaminating the wall surface, it is preferable to use a covering member as described for decontaminating the installed object.
That is, by arranging the covering member so as to cover the wall surface to be decontaminated, a region separated from other regions can be formed between the covering member and the wall surface.
Then, by reducing the volume of the region, the ventilation frequency can be increased even when ventilation is performed using a ventilation device having the same air volume.

This point will be described in detail with reference to FIG.
Here, a member 40x as illustrated in FIG. 4 is used as a covering member to form a plurality of regions 10a including individual wall surfaces to be decontaminated.
Then, in the step of specifying the decontamination target, the PCB concentration in the air near the first side wall 12a of the four side walls 12a, 12b, 12c, 12d is near the other three side walls 12b, 12c, 12d. When observed higher than the PCB concentration in the air, the covering member (40x') used for the first side wall 12a is more than the covering member (40x) used for the other side walls 12b, 12c, 12d. The volume of the region 10a'formed along the side wall 12a can be made smaller than that of the region 10a formed along the other side walls 12b, 12c, 12d.

For each of the regions 10a and 10a'formed along the side wall 12, PCB reduction air is supplied from the outside in the same manner as in the method described for the above-mentioned installation, and the air in the region is passed through a filter to be used as PCB reduction air. After that, it can be returned to the area to reduce PCB.
At this time, the amount of PCB reduction air (ventilation volume) supplied to the region 10a'formed along the first side wall 12a and the region 10a formed along the other side walls 12b, 12c, 12d is determined. Even if they are made common, decontamination will be performed with a larger ventilation frequency because the region 10a'formed along the first side wall 12a is narrower.
Therefore, according to the preferred embodiment as described above, it is possible to prevent the period of ventilation for achieving the desired reduction of PCB from being significantly prolonged only in the region 10a'along the first side wall 12a. ..

In such a decontamination step, it is preferable to carry out decontamination by the above-mentioned heating and ventilation method, it is preferable to heat the wall surface so that the temperature of the wall surface is 30 ° C. or higher, and heating is performed so that the temperature of the wall surface is 40 ° C. or higher. It is more preferable to carry out the heating, and it is particularly preferable to carry out the heating so as to reach 50 ° C. or higher.
However, in the heating / ventilation method, excessive heating of the wall surface may cause ignition. Therefore, the heating temperature of the wall surface is preferably 80 ° C. or lower even at the hottest part, and more preferably 60 ° C. or lower. preferable.
Examples of the method for heating the wall surface include light irradiation by a floodlight and the like, and a method of heating by a heater such as a radiant heater and a warm air heater.
In the present embodiment, the heating temperature in the region 10a'along the first side wall 12a may be higher than the heating temperature in the region 10a along the other side walls 12b, 12c, 12d.

In the process of decontaminating the wall surface as well as the process of decontaminating the installed object, the PCB concentration of the air in the region is monitored to determine whether or not sufficient decontamination has been performed. It is preferable to adopt a method in which air having a PCB concentration of less than 1 μg / Nm ³ is supplied into the region and ventilation is continued until the PCB concentration in the exhaust ^{becomes less than 10 μg / Nm 3.}

As mentioned above, decontamination by the simple ventilation method or the heat ventilation method is excellent in that it does not cause complicated labor, but when the amount of PCB adhering to the wall surface of the workplace is relatively large, the number of ventilations can be adjusted or within the area. It may take a long time to complete the decontamination process even if the heating temperature is adjusted.
On the other hand, the simple cleaning method and the heat cleaning method are excellent in that decontamination can be performed in a short time even when the amount of PCB adhered is relatively large.
Therefore, in the present embodiment, when the shortening of the decontamination step is prioritized on the first side wall 12a where the amount of PCB adhered is relatively large, a cleaning agent such as a simple cleaning method or a heat cleaning method is used. The method may be adopted.
That is, in the above case, a cleaning step of removing the PCB adhering to the wall surface can be carried out by cleaning the wall surface with a cleaning agent.

When cleaning the wall surface as described above, a coloring step of coloring the wall surface with a colorant that can be washed and removed with the cleaning agent can be further performed before the cleaning step.
By carrying out the coloring step, the washed part and the unwashed part can be visually distinguished.
That is, by carrying out the coloring step before the washing step, it is possible to suppress the occurrence of a portion where the washing is insufficient, and more uniform and reliable decontamination can be carried out.

In the coloring step, for example, a coloring liquid containing a coloring agent and a liquid serving as a dispersion medium for the coloring agent is prepared, and the coloring liquid is applied to a wall surface to be decontaminated to form a coating film on the wall surface. It can be carried out in the following way.
The liquid is preferably selected from liquids in which PCB is soluble.
When such a liquid is applied to the wall surface, PCB that has entered into fine gaps or the like is extracted before the cleaning step, so that the cleaning efficiency (PCB removal efficiency) in the cleaning step can be improved.
Therefore, it is preferable to secure a certain amount of time for extracting PCB with the coloring liquid between the completion of the coloring step and the start of the washing step (for example, 1 hour or more and 48 hours or less).

The coloring liquid preferably has a low viscosity in consideration of ease of application to the wall surface.
On the other hand, it is preferable to have a viscosity of a certain level or more in consideration of ensuring a certain amount of adhesion to the wall surface and exerting a sufficient function for extracting PCBs and the like.
Therefore, the viscosity of the liquid itself or the coloring liquid at 30 ° C. is preferably 10 mPa · s or more and 150 mPa · s or less.

Examples of the liquid that is the base of the coloring liquid include insulating oil and liquid paraffin.
It is preferable that the coloring liquid is maintained in a wet state without forming a dry film when applied to the wall surface.
Therefore, when an insulating oil is used as the liquid, the insulating oil preferably has a low raw material value as required based on JIS K0070: 1992, and the raw material value is preferably 100 or less. More preferably, the value is 50 or less.
Further, as the liquid, liquid paraffin is suitable in that it does not substantially contain an unsaturated component that can cause a high molecular weight.

The colorant preferably adheres to the wall surface until the PCB is sufficiently removed.
Therefore, considering the case where the decontamination step is carried out by a heat cleaning method or the like, the liquid preferably has a high boiling point.
Specifically, the boiling point (initial distilling point) of the liquid is preferably 250 ° C. or higher and 600 ° C. or lower, and more preferably 300 ° C. or higher and 550 ° C. or lower.
The colorant constituting the colorant together with the liquid is preferably one having excellent lipophilicity, and for example, an aromatic organic compound called Sudan Red or the like is preferable.

The coating of such a coloring liquid on the wall surface can be carried out by a general method such as brush coating, roller coating, or spray coating.
It is preferable that the coloring step using the coloring liquid is carried out so that the difference in color tone can be sufficiently recognized on the wall surface after coloring with respect to the wall surface before coloring.
Specifically, the coloring step is carried out so that the color difference (ΔE ^* ) is 0.5 or more when the color difference of the wall surface before and after coloring is ^{represented by the L *} , a ^* , b ^{* color system.} It is more preferable that the color difference (ΔE ^* ) is 1.5 or more, and ^{it is particularly preferable that the color difference (ΔE *} ) is 3.0 or more.

Here, in the cleaning step (decontamination step), it is preferable that the coloring liquid can be utilized as an index of whether or not the PCB adhering to the wall surface is sufficiently washed and removed.
For that purpose, it is preferable that the colorant adheres to the wall surface at least until the target decontamination level is reached in the cleaning step.
However, how the coloring liquid applied to the wall surface in the coloring step is washed and removed depends on the thickness of the coating film formed in the coloring step and the cleaning conditions in the washing step.
Therefore, in the present embodiment, a part of the wall surface to which the PCB is attached is used as a test body, or a test body to which the PCB is attached is prepared separately from the wall surface, and the test body is washed with the cleaning agent. It is preferable to carry out the test cleaning step to be performed before the cleaning step.
In the test cleaning step, by cleaning the test piece colored with the colorant, it is possible to find cleaning conditions for leaving the colorant on the wall surface until the PCB is sufficiently washed and removed.

Specific examples of the test cleaning process are shown below.
As the cleaning performed in the test cleaning process, in principle, the same method as in the subsequent cleaning process is adopted.
The wall surface cleaning performed in the test cleaning step and the cleaning step can be performed using, for example, a high pressure washer equipped with a nozzle gun.
The high-pressure washer has a nozzle that sprays the cleaning agent on the cleaning target, a hood that surrounds the nozzle to prevent the cleaning agent sprayed from the nozzle from scattering to the surroundings, and a cleaning agent immediately after being sprayed on the cleaning target. Those provided with a suction mechanism for sucking (sewage) are preferable.
Examples of the cleaning agent used in the test cleaning step and the cleaning step include water containing a surfactant and superheated steam.

The test cleaning step of the present embodiment is carried out by selecting the wall surface of the region where the highest PCB concentration is measured among the plurality of regions where the PCB concentration is measured in the concentration measuring step.
That is, in the present embodiment, the test cleaning step is carried out using the wall surface of this region as a test body.
Further, as the test body, one colored by the same method as the coloring method carried out in the coloring step is used.

In the test cleaning step, the first cleaning is performed on a part of the colored wall surface (test piece) so that the colorant remains.
Then, in the wiping survey on the portion where the first cleaning was performed, it is investigated whether or not the amount of PCB is less than the target amount.
If the amount of PCB is less than the target amount as a result of the wiping survey, in the subsequent cleaning step, all the conditions performed in this first cleaning are set to the minimum cleaning conditions and are to be cleaned. Clean the walls of the wall.
That is, in the cleaning step, the wall surface can be sufficiently decontaminated by cleaning so that no colorant remains.

If, as a result of the wiping investigation, the amount of PCB exceeds the target amount, a second cleaning is performed on another part of the previous wall surface.
In the second cleaning, the cleaning conditions are strengthened by lengthening the cleaning time, changing the type and temperature of the cleaning agent, and increasing the spraying pressure of the cleaning agent as compared with the first cleaning.
In addition, this second cleaning is also carried out under the condition that the colorant remains on the wall surface after cleaning.
Then, the decontamination status of the PCB is investigated by a wiping survey in the same manner as after the first cleaning, and if there is no problem, the cleaning step is carried out based on the conditions of the second cleaning.
If it is judged that the decontamination of PCB is insufficient even with the second cleaning, perform the third cleaning, the fourth cleaning and the cleaning with enhanced conditions in multiple stages to the extent desired. Find out the cleaning conditions where the PCB is decontaminated and the colorant remains on the wall surface after cleaning.

If the above conditions are not found, the conditions of the coloring process are reviewed, and the colorant is more difficult to be washed and removed than the first washed test piece (first test piece) (second test). The body) will be remade and the cleaning conditions will be examined again.
The second test piece can be prepared, for example, by applying a colorant thicker than that of the first test piece, or changing the colorant to be used to one that is difficult to wash with a detergent.
In this way, in the test cleaning step, a cleaning condition is found in which the amount of PCB adhered is sufficiently reduced and the colorant remains on the wall surface.
As described above, depending on the result of the test cleaning step, it may be necessary to review the conditions of the coloring step. Therefore, it is preferable to carry out the test cleaning step before the coloring step.

Further, in the test cleaning step, cleaning is performed so that the colorant remains, and the degree of adhesion of PCB is confirmed. However, in the test cleaning step, the first cleaning is performed until the colorant is exhausted, and the first cleaning is performed. A wiping survey may be performed on the cleaned portion to investigate whether or not the amount of PCB is less than the target amount.
In this case, if the amount of PCB is not less than the target amount, the condition of the colorant is changed, the first cleaning is performed again, and the amount of PCB adhered is confirmed again. By repeating this, it may be confirmed whether or not the amount of PCB adhered is sufficiently reduced when the colorant is removed.

It is preferable that the colorant remaining on the wall surface can be determined only by appearance, and the color difference (ΔE ^* ) between the wall surface after cleaning and the wall surface before coloring is preferably 0.5 or more. The color difference (ΔE ^* ) is more preferably 1.5 or more, and the color difference (ΔE ^* ) is particularly preferably 3.0 or more.
Then, if the cleaning step is carried out under the conditions found in this way, the decontamination status of the wall surface to be decontaminated can be visually grasped.

In the present embodiment, since the conditions of the cleaning step are set by the test in the region where the highest PCB concentration is measured among the plurality of regions where the PCB concentration is measured in the concentration measuring step, the other regions are also colored. Sufficient decontamination will be carried out by cleaning so that no agent remains.
It should be noted that, of the plurality of regions where the PCB concentration was measured in the concentration measuring step, the region where the highest PCB concentration was measured (first region) was the region where the second highest PCB concentration was measured (second region). ), When the PCB concentration is measured to be much higher than that of), if the conditions of the cleaning process are set with reference to the first region, excessive cleaning will be performed in other regions including the second region. become.
In such a case, the test cleaning step may be carried out using the wall surface of the second region as a test body, and the cleaning conditions of the first region may be set to conditions different from those of the other regions.
Even in such a case, reliable decontamination can be performed in a region other than the first region without requiring excessive labor.
That is, if the wall surface to be cleaned in the cleaning step is divided into a plurality of regions and the test cleaning step is performed using the region where the amount of PCB adhered per unit area is larger than that of at least one region as a test piece, the efficiency in the cleaning step is increased. Can be improved.
In addition, there is a possibility that the condition setting of the cleaning process may be inaccurate if the test cleaning process is performed using a part of the wall surface to be cleaned in the cleaning process because the adhesion of PCB is extremely local. , The test cleaning step may be carried out using a test body prepared separately from the wall surface (a test body in which PCB is more uniformly adhered to the wall surface).

(A- ₂ ) Decontamination target identification process (second and subsequent times)
After the above decontamination process is carried out, it is possible to carry out the decontamination target identification step again in order to extract the parts where the PCB residue is not reached the target level due to insufficient reduction of PCB. preferable.
In the second and subsequent decontamination target identification steps, in principle, the necessity of decontamination is determined by the concentration measurement step of measuring the PCB concentration in the air in the same manner as the first decontamination target identification step.
It is preferable to utilize the partition 40 in measuring the PCB concentration in the air and identifying the attachment location of the PCB.
Therefore, if the partition 40 that was not provided in the first decontamination target identification step is provided in the decontamination step, this partition 40 is used in the concentration measurement steps performed in the second and subsequent decontamination target identification steps. It is preferable to utilize it.
Then, in this concentration measuring step, it is preferable to confirm the presence or absence of residual PCB in each of the regions 10a and 10a'divided by the partition 40.
If PCB residue is confirmed in a part of the area in the concentration measurement step at this time, a reclassification step is carried out to divide the area where the PCB concentration was measured in the concentration measurement step into a narrow area narrower than the area. , It is preferable to measure the PCB concentration in the narrow region.
That is, in the present embodiment, after the decontamination step, the concentration measuring step including the first concentration measuring step and the second concentration measuring step is carried out two or more times, and the first concentration measuring step is performed. The concentration measurement step is carried out before the second concentration measurement step, and a reclassification step of dividing the region where the PCB concentration was measured in the first concentration measurement step into a narrow region narrower than the region is carried out. It is preferable to do so.
Then, in the second concentration measuring step, it is preferable to measure the PCB concentration in the narrow region.
This makes it possible to identify the PCB adhesion location (location requiring decontamination) in a narrower range.
Decontamination of this narrow region can be carried out in the same manner as in the above-mentioned decontamination step.
In the region where the PCB concentration is sufficiently low in the concentration measuring step and it is determined that further decontamination is not required, the partition 40 or the like is no longer necessary and may be removed.

(B- ₂ ) Decontamination process (second and subsequent times)
The decontamination steps at the locations where decontamination is determined to be necessary in the second and subsequent decontamination target identification steps will be described with reference to FIGS. 7 and 8.
In the second and subsequent decontamination steps, it is preferable to adopt a predetermined method as a specific treatment method as in the first decontamination step.
That is, the decontamination method adopted here is a method classified by case based on the measurement result of the PCB concentration in the immediately preceding concentration measurement step, and is a predetermined method as in the initial decontamination step. ..

FIG. 7 shows the state of the narrow region 10b after the reclassification step in which decontamination is performed in this decontamination step.
Then, the simple ventilation method and the heating ventilation method in the narrow region 10b will be described more specifically with reference to FIG.
FIG. 8 shows the portion shown by the broken line X in FIG. 7, and shows how decontamination is performed by ventilation in the narrow region 10b after reclassification.
_{Further, FIG. 8 shows four narrow regions 10b 1} , 10b ₂ , 10b ₃ , 10b ₄ arranged along the side wall 12b that separates the outdoor OTD and the indoor IND, and adjacent to these narrow regions on the opposite side of the side wall 12b. It shows the arrangement status of a total of eight narrow regions, 10b ₅ , 10b ₆ , 10b ₇ , and 10b ₈ , and the outline of the decontamination method in each region.

_{In the decontamination step for the first} narrow region 10b 1, a ventilation device EX different from the existing ventilation device 30 for ventilating the workplace 10 is arranged to decontaminate the narrow region.
The ventilation device EX newly provided in the decontamination step is provided with a filter capable of removing PCB such as an activated carbon filter before discharging the sucked air.
That is, the ventilation device EX can suck the air in the work place and generate an exhaust having a PCB concentration lower than that of the air.
Then, in the first narrow region 10b ₁ , decontamination is performed by ventilating the region with the ventilation device EX installed in the region.

When the heating ventilation method is carried out _{, as illustrated for the second} narrow region 10b 2, a heating device HT for heating the surface of the wall (floor wall 11, side wall 12, ceiling wall 13) of the narrow region is provided. It may be installed together with the ventilation device EX, and the wall surface may be heated by the heating device HT together with the ventilation.

Decontamination by such simple ventilation or heat ventilation may be carried out while introducing the outside air A into the narrow region as shown in _{the third narrow region 10b 3} and the fourth narrow region 10b _4.
In this case, since outside air that does not substantially contain PCB is introduced into the region, decontamination can be performed promptly.
However, in this case, it is necessary to carry out exhaust gas commensurate with the amount of outside air A introduced into _{these narrow areas 10b 3} and 10b _4.
This exhaust can be treated using, for example, the existing ventilation device 30.

Two or more of the ventilation devices EX may be installed in one narrow area requiring ventilation.
On the contrary, one ventilation device EX may be also used for ventilation of a plurality of areas.
For example, FIG. 8 illustrates how one ventilator EX arranged between _{the fifth narrow region 10b 5} and the sixth narrow region 10b _{6 decontaminates these narrow regions 10b 5} and 10b _6. Has been done.
In this case, the _{ventilation of the fifth narrow region 10b 5} and the sixth narrow region 10b ₆ may be simultaneously promoted by one ventilation device EX, and the decontamination by ventilation of the _{fifth narrow region 10b 5 is completed.} After that, the decontamination step may be carried out in such a manner that ventilation of the sixth narrow region 10b _{6 is started.}

Further, when decontaminating a plurality of narrow regions with one ventilation device EX as shown for the 7th narrow region 10b ₇ and the 8th narrow region 10b _{8, the wall surface is heated in one narrow region.} However, the wall surface may not be heated in a narrow region other than the narrow region.
In the above, the narrow region 10b after the re-division is described, but the decontamination as described above can be carried out for each region 10a before the re-division or the entire workplace before the re-division.
Further, the above decontamination can be applied to a decontamination method for an installed object.

In the present embodiment, the third decontamination target specifying step and the third decontamination step can be further carried out as needed.
After the decontamination step as described above and before the dismantling step, a graduation determination may be carried out to confirm whether or not sufficient decontamination is carried out, if necessary.
Specifically, when it is judged that decontamination is completed in all areas, the PCB concentration of the whole area is measured with the partition removed as shown in FIG. 2, and the graduation judgment is performed. Is preferable.
In this case, it is preferable to measure the concentration of PCB in the air without operating the ventilation device 30 (while restricting the generation of airflow).
The graduation determination can also be carried out by wiping the wall surface or the surface of the installed object.
Then, the dismantling step can be carried out by the same method as the dismantling method of a general facility.

In the present embodiment, in the method of dismantling a workplace where PCB-contaminated contaminants are handled, a ventilation step for ventilating the workplace and a concentration measurement for measuring the PCB concentration in the air in the workplace after the ventilation step. Since the process and the process are carried out before the dismantling of the workplace, it is possible to grasp the parts requiring decontamination and efficiently dismantle the workplace.

In the concentration measurement step of the present embodiment, since the measurement of the PCB concentration is performed at a plurality of locations in the workplace, it is possible to efficiently confirm the locations requiring decontamination.

In the present embodiment, a partitioning step is performed in which a partition is provided in the work place to divide the work place before the concentration measurement step, and in the concentration measurement step, the measurement of the PCB concentration is performed in the region divided by the division step. Therefore, the amount of PCB in the area can be grasped more accurately.

In the present embodiment, the concentration measurement step is carried out two or more times including the first concentration measurement step and the second concentration measurement step, and the first concentration measurement step is performed on the second concentration. The second concentration measurement step is carried out prior to the measurement step, and a reclassification step of dividing the region where the PCB concentration was measured in the first concentration measurement step into a narrow region narrower than the region is carried out. Since the PCB concentration is measured in the narrow region, it is possible to more reliably determine the presence or absence of PCB adhesion and to remove even a small amount of PCB adhesion without overlooking it.

In the present embodiment, the decontamination step for decontaminating the workplace is carried out before the dismantling of the workplace and after the concentration measurement step, and in the decontamination step, a plurality of predetermined methods are selected. The decontamination is carried out by the above method, and since the plurality of the methods are predetermined methods according to the level of the PCB concentration measured in the concentration measuring step, more reliable decontamination can be performed efficiently. It can be done.

In the decontamination step, decontamination is easily performed because air having a PCB concentration lower than that in the work place is supplied to the work place to carry out the decontamination.

Further, in the present embodiment, since the object to be treated is arranged in one area separated from other areas in the workplace and decontamination is performed, the PCB concentration of the air in the one area is measured in advance. It is possible to grasp the initial PCB adhesion status of the object to be processed.
Further, in the present embodiment, since air having a PCB concentration lower than that of the air in the one region is supplied to the region and the PCB is evaporated and removed from the object to be processed, the initial PCB adhesion state of the object to be processed can be grasped. At the same time, it is possible to grasp the adhesion state of the PCB after the evaporation and removal of the PCB.
Therefore, in the present embodiment, it is possible to grasp how much the amount of PCB adhered to the object to be treated has been reduced by the evaporation removal.
Therefore, the present embodiment has an advantage that the required amount of the air (air for reducing PCB) to be supplied into the region can be grasped in order to sufficiently reduce the amount of PCB adhered to the object to be treated. ..

That is, in the present embodiment, a target value is set in advance for the PCB concentration in the air in the region, which is an index of the amount of PCB adhered to the object to be treated, and a certain amount of PCB reduction air is supplied into the region. By obtaining the PCB concentration in the air (after performing a certain amount of evaporation and removal), the difference between the PCB concentration and the initial PCB concentration, the difference between the PCB concentration and the target value, and the like are obtained. In the future, the amount of PCB reduction air to be supplied to the region can be grasped.

In the present embodiment, the above-mentioned advantageous effects are exhibited by providing the above-mentioned preferable configuration. Therefore, the embodiment of the present invention has been described based on a specific case. It is not limited in any way.
That is, in carrying out the present invention, various modifications may be made to the above examples.

10: Workplace
10a: (Divided) area 10b: Narrow area 11: Floor wall 12: Side wall 13: Ceiling wall 30: Ventilation device 40: Partition

Claims (7)

A method of dismantling a workplace where PCB-contaminated contaminants were handled.
Ventilation process to ventilate the workplace and
A concentration measuring step of measuring the PCB concentration in the air in the workplace after the ventilation step, and a concentration measuring step.
The decontamination step of decontaminating the workplace is carried out before the dismantling of the workplace.
The decontamination step is carried out after the concentration measurement step,
In the decontamination step, the decontamination is carried out by a method selected from a plurality of predetermined methods, and the decontamination step is performed.
A method of dismantling a workplace, wherein the plurality of methods are predetermined methods according to the level of PCB concentration measured in the concentration measuring step. The method for disassembling a workplace according to claim 1, wherein in the concentration measuring step, the measurement of the PCB concentration is performed at a plurality of locations in the workplace. Before the concentration measurement process, a partition is provided in the workplace to divide the workplace.
The method for disassembling a workplace according to claim 1 or 2, wherein in the concentration measuring step, the measurement of the PCB concentration is carried out in the region divided by the dividing step. The concentration measurement step is carried out two or more times including the first concentration measurement step and the second concentration measurement step, and the concentration measurement step is carried out.
The first concentration measuring step is performed before the second concentration measuring step.
A re-sorting step was carried out to divide the region where the PCB concentration was measured in the first concentration measuring step into a narrow region narrower than the region.
The method for disassembling a workplace according to claim 3, wherein in the second concentration measuring step, the PCB concentration is measured in the narrow region. Performed before Kijo dyeing process prior SL after the second density measuring step, the method of multiple is, is in a predetermined manner according to the level of the PCB concentration measured by the second concentration measuring step The method for disassembling the workplace according to claim 4. The method for dismantling a workplace according to any one of claims 1 to 5 , wherein in the decontamination step, air having a PCB concentration lower than that in the workplace is supplied to the workplace to carry out the decontamination. It is a decontamination method for workplaces where a decontamination process is carried out to decontaminate workplaces where PCB-contaminated contaminants are handled.
A ventilation step of ventilating the workplace and a concentration measuring step of measuring the PCB concentration in the air in the workplace after the ventilation step are performed before the decontamination step .
In the decontamination step, the decontamination is carried out by a method selected from a plurality of predetermined methods, and the decontamination step is performed.
A method for decontaminating a workplace, wherein the plurality of methods are predetermined methods according to the PCB concentration step measured in the concentration measuring step.

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