JP2016215112A - Contaminated soil cleaning equipment and cleaning method for contaminated soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide contaminated soil cleaning equipment capable of efficiently performing operation of cleaning heavy metal contaminated soil using an iron powder by simple equipment, and to provide a cleaning method for contaminated soil using the contaminated soil cleaning equipment.SOLUTION: A heavy metal removal apparatus comprises: a heavy metal adsorption tank in which contaminated muddy water and an iron powder are stirred and mixed to prepare iron powder added muddy water; and a centrifugal separator that is disposed downstream of the heavy metal adsorption tank to gravity separate the iron powder added muddy water into cleaned muddy water and an iron powder-containing separated material containing the iron powder adsorbing heavy metals. A circulation passage of the iron powder is formed by arranging three or more of the heavy metal removal apparatuses so that the iron powder-containing separated material gravity separated by the centrifugal separator of the heavy metal removal apparatus located upstream is directly charged down to the heavy metal adsorption tank of the heavy metal removal apparatus located downstream.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a contaminated soil cleaning facility used when cleaning heavy metal contaminated soil using iron powder, and a method for cleaning contaminated soil using the contaminated soil cleaning facility.

  For example, naturally-derived heavy metal-contaminated soil generated by shields and tunnel construction is often viscous soil containing a large amount of fine particles. Therefore, the inventors have developed a method for cleaning heavy metal contaminated soil using iron powder as a method for efficiently removing heavy metals including arsenic contained in cohesive soil.

  As disclosed in Patent Document 1, the method for cleaning heavy metal-contaminated soil using iron powder is after stirring and mixing mud containing arsenic and iron powder for a predetermined time in an arsenic adsorption tank to produce iron powder-added mud water Then, this is subjected to specific gravity separation in a centrifuge into muddy water containing iron powder adsorbing arsenic and muddy water not containing arsenic.

  The arsenic-free muddy water is supplied to the slurry tank, volume-reduced and dehydrated to become a cake, which is carried out as healthy industrial waste. On the other hand, the muddy water containing the iron powder adsorbing arsenic was once stored in the iron powder pretreatment tank in order to reuse the iron powder.

JP 2014-188408 A

  However, if mud containing iron powder adsorbed arsenic stored in the iron powder pretreatment tank is supplied to the arsenic adsorption tank as it is to be reused, it is separated by a centrifuge and has a specific gravity and viscosity. Since both are large, pumping cannot be performed.

  For this reason, in patent document 1, an iron powder stock tank is installed in the downstream of an iron powder pretreatment tank, and the muddy water containing the iron powder which adsorb | sucked the arsenic stored in the iron powder pretreatment tank is made into an iron powder stock tank. The iron powder mixture that can be pumped by performing appropriate water addition is prepared and supplied to the arsenic adsorption tank, which requires a great deal of cost and labor.

  Further, in Patent Document 1, since a plurality of arsenic adsorption tanks are installed, the same number of iron powder stock tanks as the number of arsenic adsorption tanks are used so that the iron powders used in each arsenic adsorption tank do not mix with each other. It was necessary not only to increase the equipment cost but also to secure a vast site for the equipment.

  The present invention has been made in view of such a problem, and its main purpose is contamination that can efficiently carry out an operation of washing heavy metal-contaminated soil using iron powder with simple equipment. It is to provide a soil cleaning facility and a method for cleaning contaminated soil using the contaminated soil cleaning facility.

  In order to achieve such an object, the contaminated soil cleaning facility of the present invention stores a contaminated mud containing viscous soil contaminated with heavy metals, and manages and adjusts the specific gravity of the contaminated mud, and is supplied from the mud tank. Three or more heavy metal removing devices for cleaning the contaminated mud water with iron powder and producing the washed mud water from which the heavy metals have been removed, and a washing mud tank for storing the washing mud water discharged from each of the heavy metal removing devices And the heavy metal removing device stirs and mixes the contaminated mud water and the iron powder and adsorbs the heavy metal in the contaminated mud water to the iron powder, Specific gravity separation of the heavy metal adsorption tank to be prepared and the iron powder-added muddy water separated into the washing muddy water and the iron powder-containing separation containing the iron powder adsorbed with the heavy metal, disposed on the downstream side of the heavy metal adsorption tank A centrifuge, The iron powder-containing separation obtained by separating the specific gravity of two or more heavy metal removal devices by the centrifugal separator of the heavy metal removal device located upstream is directly dropped into the heavy metal adsorption tank of the heavy metal removal device located downstream. It arrange | positions so that the circulation path of the said iron powder may be formed.

  In the contaminated soil cleaning equipment of the present invention, among the three or more heavy metal removal devices, the heavy metal adsorption tank provided in at least one heavy metal removal device is connected to a waste sludge water tank for discarding the iron powder-containing separation. It is characterized by being.

  The contaminated soil cleaning equipment of the present invention is for supplying the iron powder-added muddy water from the muddy water tank to the heavy metal adsorbing tank and supplying the contaminated mud water to the centrifuge from the heavy metal adsorbing tank. An automatic valve and a pump are respectively provided in the drainage pipe, and an automatic valve is provided in the drainage pipe for supplying the cleaning mud water from the centrifuge to the cleaning mud tank. The terminal device which controls the action | operation of the said pump accompanying is provided, It is characterized by the above-mentioned.

  According to the contaminated soil washing facility of the present invention, the iron powder-containing separation separated by specific gravity in the centrifuge of the heavy metal removal device located on the upstream side is directly dropped into the heavy metal adsorption tank of the heavy metal removal device located on the downstream side. it can. This eliminates the need for an iron powder pretreatment tank that temporarily stores the iron powder separated by the centrifuge, and even if the iron powder is contained in muddy water having a large specific gravity and viscosity, Since there is no need to recreate the solution as possible, an iron powder stock tank can be dispensed with. Not only can the equipment cost be greatly reduced, it is also possible to install contaminated soil cleaning equipment in a narrow site. It becomes.

  Moreover, since the diluting water required for recreating the iron powder-containing separated product into a solution that can be pumped is not necessary, the material cost can be greatly reduced.

  In addition, there is no need to re-create the iron powder-containing separation into a solution that can be pumped, so not only the work time is greatly reduced, but also problems related to pumping such as clogging of piping are taken into account. Since it is not necessary, the efficiency of the entire work can be greatly improved.

  The contaminated soil cleaning method of the present invention is the first step of mixing the muddy water and the iron powder or the iron powder-containing separated material in the heavy metal adsorption tank in each of the heavy metal removing devices, the muddy water and the iron. Secondly, the iron powder-added muddy water is produced by mixing and stirring the powder or the iron powder-containing isolate to adsorb heavy metals in the contaminated muddy water to the iron powder contained in the iron powder or the iron powder-containing isolate. And the step of supplying the iron powder-added muddy water from the heavy metal adsorption tank to the centrifuge and repeatedly performing the specific gravity separation into the washing muddy water and the iron powder-containing separator, and at least 3 The work process performed simultaneously in each of the two heavy metal removal apparatuses is a process that precedes the process of performing the work process performed in the heavy metal removal apparatus located on the downstream side with respect to the heavy metal removal apparatus located on the upstream side. The specific gravity is separated from the heavy metal removal device located upstream in the third step in the heavy metal adsorption tank in the heavy metal removal device located downstream in the first step. It is characterized by dropping a separated product containing iron powder.

  The contaminated soil cleaning method of the present invention is characterized in that the second step is continuously performed a plurality of times and then the third step is performed.

  According to the method for cleaning contaminated soil of the present invention, the iron powder circulates through three or more heavy metal removal devices in order, without sleeping, while adsorbing heavy metals contained in the washing mud water in each heavy metal removal device. This eliminates the time temporarily stored in the iron powder pretreatment tank as in the prior art and the time for performing the water addition work so as to obtain a solution that can be pumped, thereby improving work efficiency and reducing work time. It can be greatly shortened.

  According to the present invention, when separating iron powder adsorbed heavy metal with a centrifuge from iron powder added mud prepared by stirring and mixing iron powder and contaminated mud, the centrifuge of the heavy metal removal device located upstream is used. The iron powder separated in this way can be dropped directly into the heavy metal adsorption tank of the heavy metal removal device located downstream without temporarily storing it, so that the iron powder is contained in the iron powder-containing isolate with both high specific gravity and viscosity. Even if it does, an excessive installation is not required and it becomes possible to repeatedly carry out the purification work of the contaminated soil efficiently with a plurality of heavy metal removing devices.

It is a figure which shows the outline of a contaminated soil washing | cleaning equipment. It is a figure which shows the outline of a muddy water treatment facility. It is a flowchart which shows the flow of the washing | cleaning method of heavy metal contaminated soil. It is a figure which shows the flow of the iron powder at the time of implementing the washing | cleaning method of heavy metal contaminated soil. It is a flowchart which shows the flow of the washing | cleaning method of heavy metal contaminated soil when the flow of iron powder is made into 2 systems. It is a figure which shows the operation | work condition of the washing process process (s2) of contaminated mud water (the 1). It is a figure which shows the operation | work condition of the washing process process (s2) of contaminated mud water (the 2). It is a figure which shows the operation | work condition of the washing process process (s2) of contaminated mud water (the 3). It is a figure which shows the operation | work condition in the washing process process (s2) of contaminated mud water at the time of using four heavy metal removal apparatuses with which a contaminated soil washing | cleaning equipment is equipped.

  The present invention is a method for cleaning heavy metal-contaminated soil using iron powder having the property of efficiently adsorbing and immobilizing heavy metals such as arsenic, fluorine, boron, selenium, hexavalent chromium, cadmium, lead, and cyanide By adding iron powder to the muddy water containing heavy metal contaminated soil, stirring and mixing, adsorbing the heavy metal fine particles adhering to the soil particles in the muddy water to the iron powder surface and immobilizing them, the heavy metal contaminated soil is It is to be washed. Also, paying attention to the fact that iron powder has a limit on the amount of heavy metals that can be adsorbed and immobilized per fixed amount, and can be used repeatedly until the ability to adsorb and immobilize is lost, the initially dropped iron powder is contaminated with heavy metals. It is used repeatedly for soil washing.

  Below, the contaminated soil washing | cleaning method used when wash | cleaning heavy metal-contaminated soil using iron powder and the cleaning method of contaminated soil using a contaminated soil washing | cleaning equipment are demonstrated using FIGS.

<Contaminated soil cleaning equipment>
First, the contaminated soil washing | cleaning equipment 1 used when wash | cleaning heavy metal contaminated soil using iron powder is demonstrated with reference to FIGS. In describing the contaminated soil cleaning facility 1, the upstream side and the downstream side are defined from the moving direction of the iron powder 10.

  As shown in FIG. 1, the contaminated soil cleaning facility 1 includes a mud tank 2 and three heavy metal removing devices 3.

  The muddy water tank 2 is a tank in which contaminated muddy water 100 containing viscous soil containing heavy metals is stored, and a specific gravity detector 21 that detects the specific gravity of the stored contaminated muddy water 100 and a heavy metal removing device 3 described later. A first mud discharge pipe 22 provided with an electromagnetic valve for supplying the contaminated mud water 100 is provided. Specific gravity management is adjusted by the specific gravity detector 21 so that the stored contaminated mud 100 is always supplied to the heavy metal removing device 3 with a stable specific gravity.

  The muddy water tank 2 in the present embodiment is a surplus muddy water tank 503 provided in the muddy water treatment facility 50 employed in the muddy water shield method. As shown in FIG. 2, the muddy water treatment facility 50 separates the excavated sediment from the mud discharged from the muddy water type shield excavator 60 and supplies the mud water from which the excavated sediment has been removed to the pressure chamber 61 of the shield excavator 60. Thus, it is an apparatus for circulating and reusing for stabilizing the face and fluid transport of excavated soil.

  Specifically, it includes a solid-liquid separation device 501 that is a primary processing plant, an adjustment tank 502 and an excess mud tank 503 that constitute the secondary processing plant, and the exhaust discharged from the pressure chamber 61 of the shield excavator 60. As for the muddy water, soil particles of 75 μm or more are separated as a primary treatment by the solid-liquid separator 501, and the separated sandy matter is carried out as the primary treatment soil. On the other hand, the drained water from which the soil particles of 75 μm or more have been removed is supplied to the adjustment tank 502, adjusted for specific gravity and viscosity, and then sent to the pressure chamber 61 of the shield excavator 60 again.

  Then, of the muddy water containing soil particles of less than 75 μm generated by the adjustment of the adjustment tank 502, surplus muddy water that has become surplus in order to suppress an increase due to the inflow of groundwater and an increase in the specific gravity of the muddy water is supplied to the excess muddy water tank 503. Is done. In the present embodiment, since the surplus muddy water tank 503 is the muddy water tank 2, the surplus muddy water containing soil particles of less than 75 μm is washed as the contaminated muddy water 100.

  In addition, the muddy water treatment facility 50 is not necessarily limited to that employed in the muddy water type shield method, for example, a muddy water method such as a continuous underground wall method, or a muddy water state by adding water to the excavated soil. It may be employed in a classification and cleaning facility that purifies contaminated soil. Further, the muddy water tank 2 does not necessarily have to be used as the excess muddy water tank 503 provided in the muddy water treatment facility 50, and may be installed independently.

  As shown in FIG. 1, each heavy metal removing device 3 includes a heavy metal adsorbing water tank 4 and a centrifugal separator 5 disposed on the downstream side thereof.

  The heavy metal adsorbing water tank 4 is a tank for producing the iron powder-added mud water 101 while stirring and mixing the contaminated mud water 100 and the iron powder 10 supplied from the mud water tank 2 and adsorbing the heavy metal in the contaminated mud water 100 to the iron powder 10. Yes, a stirring device 41 is provided, and a second mud discharge pipe 42 provided with an electromagnetic valve for supplying the iron powder-added mud water 101 to the centrifuge 5 is provided. In addition, the heavy metal adsorption water tank 4 may be appropriately provided with a liquid level meter, a specific gravity meter, a viscometer, or the like as necessary.

  The centrifuge 5 is a device that separates the specific gravity of the iron powder-added mud water 101 supplied from the heavy metal adsorption water tank 4 and employs a cyclone in the present embodiment. The cyclone throws a solid mixed liquid or the like into the cylindrical container so as to draw a vortex from the circumferential direction, so that the iron powder 10 having a high specific gravity collides with the inner wall of the cylindrical container by the centrifugal separation and separates downward. In addition, it has a function of discharging other muddy water upward from the center of the cylinder. As a result, the iron powder-added muddy water 101 is separated into the iron powder 10 and the iron powder-containing separated product 102 containing soil particles that could not be separated, and the cleaning muddy water 103 from which heavy metals have been removed.

  The heavy metal removing device 3 configured as described above is arranged such that the centrifuge 5 of the heavy metal removing device 3 located on the upstream side is located above the heavy metal adsorbing water tank 4 of the heavy metal removing device 3 located on the downstream side. . Thereby, for example, the iron powder-containing separated product 102 separated by the centrifugal separator 5 of the heavy metal removing device 3 located on the leftmost side is not used by a pumping device such as a pump, and the heavy metal removing device 3 located in the center is used. The heavy metal adsorption water tank 4 can be directly dropped.

  Further, the three heavy metal removing devices 3 are continuously formed so as to form a circulation path in which the iron powder 10 dropped from the iron powder tank 7 described later to the heavy metal adsorption water tank 4 circulates through all the heavy metal removing devices 3. Is arranged. In other words, the iron powder-containing separated product 102 separated by the centrifugal separator 5 of the heavy metal removal device 3 located on the rightmost side is used without using a pumping device such as a pump, and the heavy metal of the heavy metal removal device 3 located on the leftmost side. It can be dropped directly into the adsorption water tank 4. Thereby, all the three heavy metal adsorption water tanks 4 produce the iron powder-added mud water 101 while adsorbing the heavy metals in the contaminated mud water 100 to the iron powder 10 when the electromagnetic valve of the second mud pipe 42 is closed. The iron powder 10 is contained in the heavy metal adsorption water tank 4 of the heavy metal removing device 3 located downstream when the electromagnetic valve of the second mud pipe 42 is open, functioning as a tank for adsorbing the iron powder 10. It functions as a tank for stocking the iron powder 10 for supplying the iron powder-containing separated product 102.

  In the embodiment shown in FIG. 1, three heavy metal removing devices 3 and four in the embodiment shown in FIG. 8 are installed. However, the number of heavy metal removing devices 3 is not limited as long as the number is three or more. It is not a thing.

  Moreover, the contaminated soil washing | cleaning equipment 1 is equipped with the washing | cleaning mud water tank 6, the iron powder tank 7, the waste sludge water tank 8, the iron powder separation apparatus 9, and the waste iron powder processing pit 91, as shown in FIG.

  The cleaning mud tank 6 is connected to the centrifuge 5 via a third drain pipe 51 provided with an electromagnetic valve, and is supplied with the cleaning mud 103 from which heavy metals have been removed.

  The iron powder tank 7 stores iron powder 10 for adsorbing heavy metals contained in the contaminated mud water 10, and performs an initial drop to the heavy metal adsorption water tank 4 of the heavy metal removal device 3. Further, even when the amount of the iron powder 10 is reduced from the specified amount by circulating the heavy metal removing device 3, the iron powder 10 is additionally charged from the iron powder tank 7 to the heavy metal adsorption water tank 4.

  On the other hand, the waste sludge water tank 8 is connected to the heavy metal adsorbing water tank 4 through the fourth exhaust pipe 43 provided with an electromagnetic valve, and the iron powder-containing separated product 102 is supplied from the heavy metal adsorbing water tank 4. is there. The iron powder separator 9 separates the iron powder-containing separation 102 supplied from the waste sludge water tank 8 into the iron powder 10 and the final iron powder-containing separation 104 containing earth and sand that could not be separated, and the cleaning mud water 103. Is. The waste iron powder processing pit 91 is a pit into which the final iron powder-containing separation 104 discharged from the iron powder separation device 9 is dropped.

  In the present embodiment, a screw decanter is adopted as the iron powder separation device 9, but the present invention is not limited to this. For example, in the iron powder-containing separated material 102 such as an underwater specific gravity sorter or a magnetic sorter. As long as the iron powder 10 can be separated from the steel, any of them may be adopted. Further, any one of the above-described iron powder separation devices 9 may be adopted, but a plurality of them may be used together to more reliably separate the iron powder 10 from the iron powder-containing separated product 102.

  As described above, the contaminated soil washing facility 1 has the heavy metal adsorption tank of the heavy metal removing device 3 located on the downstream side of the iron powder-containing separated material 102 separated by specific gravity in the centrifugal separator 5 of the heavy metal removing device 3 located on the upstream side. 4 to drop directly. This eliminates the need for temporary storage of the iron powder 10 separated by the centrifugal separator 5 as in the prior art, and even if the iron powder 10 is contained in the iron powder-containing separated mud water 102, There is no need to recreate the solution for pumping. For this reason, not only can the work process be reduced, but also the equipment can be reduced in scale, equipment costs can be greatly reduced, and the contaminated soil cleaning equipment 1 can be installed in a narrow site. .

<How to clean heavy metal contaminated soil>
The contaminated soil cleaning method for cleaning the contaminated mud 100 with the iron powder 10 using the above-described contaminated soil cleaning facility 1 will be described in detail below with reference to FIGS.

  As shown in the flowchart of FIG. 3, the cleaning method for the contaminated soil 100 includes a pretreatment step s1, a cleaning treatment step s2 for the contaminated mud water 100, a disposal processing step s3 for the iron powder-containing material 102, and a dehydration treatment step for the cleaning mud water 103. It consists of four steps s4.

<Pretreatment process: s1>
Prior to washing the contaminated mud 100, the specific gravity is adjusted by adding water to the contaminated mud 100 stored in the mud tank 2, and the adjustment is performed so that the contaminated mud 100 does not always exceed the upper limit of the specific gravity. The upper limit of the specific gravity is such that when the iron powder-added mud water 101 prepared by adding the iron powder 10 to the contaminated mud water 100 is supplied to the centrifuge 5, there are few soil particles remaining in the iron powder-containing separated material 102, It may be set in advance by an indoor experiment or the like so that the iron powder 10 remaining in the cleaning mud 103 is reduced.

<Cleaning process of contaminated mud water: s2>
The contaminated mud water 100 whose specific gravity is controlled in the pretreatment step (s1) is washed by contacting with the iron powder 10 to obtain the iron powder-containing separated product 102 and the washed mud water 103. Cleaning of the contaminated mud water 10 consisting of the above steps is carried out by each of the three heavy metal removing devices 3. At this time, the three heavy metal removing devices 3 do not operate simultaneously, but operate one by one in order. The flow of processing will be described while following the movement of the iron powder 10 initially dropped from the iron powder tank 7 shown in FIG.

First, the following first to third steps are performed in the heavy metal removing device 3 located on the leftmost side.
The iron powder 10 stored in the iron powder tank 7 is dropped into the heavy metal adsorbing water tank 4 of the heavy metal removing device 3 located at the leftmost position. Then, the contaminated mud water 100 is supplied from the mud tank 2 and the contaminated mud water 100 and the iron powder 10 are mixed (first step). The contaminated mud water 100 and the iron powder 10 stored in the heavy metal adsorbing water tank 4 are stirred and mixed by the stirring device 41, and the iron powder-added mud water 101 is produced while adsorbing the heavy metal in the contaminated mud water 100 to the iron powder 10 (first). Step 2). Thereafter, the iron powder-added muddy water 101 is supplied to the centrifuge 5 and separated into the iron powder-containing separated product 102 and the washed muddy water 103 (third step). The cleaning muddy water 103 is supplied to the cleaning muddy water tank 6, and the iron powder-containing separated product 102 is dropped into the heavy metal adsorption water tank 4 of the heavy metal removing device 3 located at the center. Thus, the heavy metal adsorbing water tank 4 of the heavy metal removing device 3 located on the leftmost side is in an empty state.

Next, in the heavy metal removing device 3 located in the center, the following first to third steps are performed.
Supplying the contaminated mud water 100 to the heavy metal adsorbing water tank 4 of the heavy metal removing device 3 located in the center where the iron powder-containing separated product 102 separated in the third step of the heavy metal removing device 3 located on the leftmost side is dropped, The contaminated mud water 100 and the iron powder-containing separated product 102 are mixed (first step). Thus, in the 1st process in each subsequent heavy metal removal apparatus 3, the iron powder 10 supplied from the iron powder tank 7 to the heavy metal adsorption | suction water tank 4 of the heavy metal removal apparatus 3 located in the leftmost is iron powder containing. It will be circulated and supplied in the state of being contained in the separated product 102.

  Then, the contaminated mud water 100 stored in the heavy metal adsorbing water tank 4 and the iron powder-containing isolate 102 are stirred and mixed by the stirring device 41, and the heavy metal in the contaminated mud water 100 is added to the iron powder 10 contained in the iron powder-containing isolate 102. While adsorbing, iron powder-added mud water 101 is produced (second step). Thereafter, when the third step described above is performed, the cleaning mud water 103 is supplied to the cleaning mud tank 6, and the iron powder-containing separated material 102 is placed in the heavy metal adsorption water tank 4 of the heavy metal removing device 3 located at the rightmost position. Dropped. Thus, the heavy metal adsorbing water tank 4 of the heavy metal removing device 3 located in the center becomes empty.

Then, the following 1st-3rd process is implemented in the heavy metal removal apparatus 3 located in the rightmost.
From the mud tank 2 to the heavy metal adsorbing water tank 4 of the heavy metal removing apparatus 3 located at the rightmost position where the iron powder-containing separated product 102 separated in the third step of the heavy metal removing apparatus 3 located in the center is dropped. 100 is supplied, and the contaminated mud water 100 and the iron powder-containing separator 102 are mixed (first step). Next, the second step is performed, and then the third step is performed. The cleaning mud water 103 is supplied to the cleaning mud tank 6 and the iron powder-containing separation 102 is removed from the leftmost heavy metal. It is dropped into an empty heavy metal adsorption water tank 4 in the apparatus 3. Thus, the heavy metal adsorbing water tank 4 of the heavy metal removing device 3 located on the rightmost side becomes empty.

  In this way, the iron powder 10 initially dropped in the heavy metal adsorption water tank 4 of the heavy metal removing device 3 located on the leftmost side is repeatedly used in each of the three heavy metal removing devices 3. The upper limit value of the number of diversions is calculated, and the number of warnings before reaching the upper limit value of the diversion number in consideration of the safety factor may be set.

  Then, as described above, after the iron powder 10 makes a round while cleaning the contaminated mud water 100 in each of the three heavy metal removing devices 3, the number of diversions of the iron powder 100 contained in the iron powder-containing separated product 102 indicates the number of warnings. If it does not exceed and the contaminated mud 100 stored in the mud tank 2 remains, the process returns to the heavy metal removing device 3 located at the leftmost and the washing of the contaminated mud 100 is repeated.

  On the other hand, in the course of the contaminated mud washing process (s2), when the number of diversions of the iron powder 100 contained in the iron powder-containing separated product 102 exceeds the number of warnings, or the contaminated mud 100 stored in the mud tank 2 is exhausted. In this case, the iron powder-containing separated product 102 is supplied to the waste sludge water tank 8.

<Disposal process of iron powder-containing separated product 102: s3>
This is a process for discarding the iron powder-containing separated product 102 supplied to the waste sludge water tank 8 through the above-described contaminated mud water cleaning process (s2).
The iron powder-containing separated substance 102 stored in the waste sludge water tank 8 is adjusted to have a specific gravity suitable for being separated by the iron powder separator 9 by being appropriately hydrated in the waste sludge water tank 8. Then, it is supplied to the iron powder separation device 9 and separated into a final iron powder-containing separation 104 containing the iron powder 10 and the earth and sand that could not be separated and the cleaning mud water 103. Then, the final iron powder-containing separated product 104 is dropped into the waste iron powder processing pit 91 and then reduced in volume and dehydrated to become a cake, which is carried out as industrial waste containing heavy metals.

<Dehydration process of cleaning mud 103: s4>
This is a step of dehydrating the cleaning mud 103 supplied to the cleaning mud tank 6 through the cleaning step (s2) of the contaminated mud or the disposal step (s3) of the iron powder-containing separated product 102.
The cleaning muddy water 103 stored in the cleaning muddy water tank 6 is supplied to a slurry tank (not shown), undergoes volume reduction and dehydration, becomes a cake, and is carried out as healthy industrial waste or purified soil.

  In the present embodiment, after the iron powder 10 makes a round while washing the contaminated mud water 100 in each of the three heavy metal removing devices 3, the number of times of diversion of the iron powder 10 contained in the iron powder-containing separated product 102, and Although the amount of the contaminated mud water 100 stored in the mud tank 2 is confirmed, the present invention is not necessarily limited to this. Each time the cleaning process of the contaminated mud water 100 is completed in each heavy metal removal device 3, the above confirmation is performed. May be performed.

  By the way, in the contaminated mud water washing step (s2), the iron powder 10 stored in the iron powder tank 7 or the iron powder-containing separated material 102 that is separated by the centrifugal separator 5 in the third step is used. Then, after dropping into the empty heavy metal adsorption water tank 4, the contaminated mud water 100 was supplied, and the contaminated mud water 100 and the iron powder 10 or the iron powder-containing separated substance 102 were mixed, which was defined as the first step. However, the first step is not necessarily limited to this method, and the iron separated in the iron powder tank 7 or the centrifuge 5 stored in the iron powder tank 7 with respect to the heavy metal adsorption water tank 4. The first step may be performed by simultaneously dropping the powder-containing separated material 102 and supplying the contaminated mud water 100 and mixing the contaminated mud water 100 and the iron powder 10 or the iron powder-containing separated material 102.

  That is, paying attention to the dropping of the iron powder-containing separated product 102, the third step in the heavy metal removing device 3 located at the leftmost and the first step in the heavy metal removing device 3 located in the center are simultaneously performed. Similarly, the third step in the heavy metal removing device 3 located at the center and the first step in the heavy metal removing device 3 located at the rightmost, and the third step and the leftmost in the heavy metal removing device 3 located at the rightmost Each of the first steps in the heavy metal removing device 3 located at the same time is performed simultaneously. If it carries out like this, the 3rd process of the heavy metal removal apparatus 3 located in an upstream, and the 1st process of the heavy metal removal apparatus 3 located in a downstream will be performed simultaneously, and the cleaning process process (s2) of contaminated mud water The work time can be shortened, and the work efficiency can be improved.

  Therefore, as another embodiment of the method for cleaning heavy metal contaminated soil, the supply of contaminated mud water 100 to the heavy metal adsorption tank 4 of the heavy metal removal device 3 located on the downstream side of the above-described empty state, and the upstream side A method of simultaneously dropping the iron powder-containing separated material 102 separated in the third step of the heavy metal removing device 3 that is located, mixing the contaminated mud water 100 and the iron powder-containing separated material 102, and setting this as the first step. Show.

  Moreover, in this embodiment, the flow of the iron powder 10 shown in FIG. 4 (b) is added to the flow of the iron powder 10 shown in FIG. 4 (a), and the flow of the iron powder 10 as shown in FIG. An example in which three heavy metal removing devices 3 are operated more efficiently is shown.

Hereinafter, another embodiment of the contaminated soil cleaning method will be described with reference to FIGS.
Note that the pretreatment step s1, the waste treatment step s3 of the iron powder-containing material 102, and the dehydration treatment step s4 of the cleaning mud water 103 are omitted because they are the same as those in the above-described embodiment, and two types of iron powder 10 Focusing on the cleaning process step s2 of the contaminated mud 100 with the flow of the above, detailed description will be made in units of processing time of the first batch to the ninth batch.

  The first to third batches are preparation steps for operating all three heavy metal removing devices 3.

<First batch: Fig. 6 (a)>
At the leftmost heavy metal removing device 3, iron powder 10 (first iron powder 10) stored in the iron powder tank 7 is added, and at the same time, the contaminated muddy water 100 from the mud tank 2 to the heavy metal adsorption water tank 4. And contaminated mud water 100 and iron powder 10 are mixed (first step).
At this time, the heavy metal removing device 3 located at the center and the heavy metal removing device 3 located at the rightmost are not in operation.
<Second batch: FIG. 6B>
In the heavy metal removing device 3 located on the leftmost side, the contaminated mud water 100 and the iron powder 10 stored in the heavy metal adsorbing water tank 4 are stirred and mixed by the stirring device 41, and the heavy metal in the contaminated mud water 100 is adsorbed to the iron powder 10. The iron powder-added mud water 101 is prepared (second step).
The heavy metal removing device 3 located in the center is not in operation.
In the heavy metal removal device 3 located on the rightmost side, the iron powder 10 (second iron powder 10) stored in the iron powder tank 7 is added, and at the same time, the contaminated mud water 100 from the mud tank 2 is added to the heavy metal adsorption tank 4. Supply and mix the contaminated mud water 100 and the iron powder 10 (first step).
<Third batch: FIG. 6 (c)>
In the heavy metal removal device 3 located on the leftmost side, the iron powder-containing separation product 102 is separated from the iron powder-added mud water 101 by the centrifugal separator 5 (third step), and the heavy metal adsorption device 3 located in the center absorbs the heavy metal. Drop into the aquarium 4. As a result, the heavy metal removing device 3 located on the leftmost side is in an empty state.
In the heavy metal removing device 3 located in the center, the iron powder-containing separated product 102 separated in the third step in the heavy metal removing device 3 located on the leftmost side is dropped into the heavy metal adsorbing water tank 4 and at the same time from the muddy water tank 2. The contaminated mud water 100 is supplied, and the contaminated mud water 100 and the iron powder containing separated material 102 are mixed (first step).
In the heavy metal removing device 3 located on the rightmost side, the contaminated mud water 100 and the iron powder 10 stored in the heavy metal adsorbing water tank 4 are stirred and mixed by the stirring device 41, and the heavy metal in the contaminated mud water 100 is adsorbed to the iron powder 10. The iron powder-added mud water 101 is prepared (second step).

Thus, all the three heavy metal removal apparatuses 3 will start operation in the third batch.
From the 4th batch to the 6th batch shown below, the number of diversions of the iron powder 100 contained in the iron powder-containing separated product 102 does not exceed the number of warnings, and the contaminated mud water 100 stored in the mud tank 2 remains. In this case, the cleaning of the contaminated mud 100 is repeated.

<Fourth batch: FIG. 7 (a)>
At the leftmost heavy metal removing device 3, the iron powder-containing separated material 102 separated in the third step in the rightmost heavy metal removing device 3 is dropped into the empty heavy metal adsorption water tank 4. Then, the contaminated mud water 100 is supplied from the mud tank 2, and the contaminated mud water 100 and the iron powder-containing separated substance 102 are mixed (first step).
In the heavy metal removal device 3 located in the center, the contaminated mud water 100 stored in the heavy metal adsorption water tank 4 and the iron powder-containing separated material 102 are stirred and mixed by the stirring device 41, and the iron powder 10 contained in the iron powder-containing separated material 102 is mixed. The iron powder-added mud water 101 is produced while adsorbing heavy metals in the contaminated mud water 100 (second step).
In the heavy metal removing device 3 located on the rightmost side, the third step is performed, and the iron powder-containing separation 102 separated by the centrifugal separator 5 is placed in the heavy metal adsorption water tank 4 of the heavy metal removing device 3 located on the leftmost side. Drop it. As a result, the heavy metal removing device 3 located on the rightmost side is in an empty state.

<Fifth batch: FIG. 7 (b)>
In the heavy metal removing device 3 located on the leftmost side, the second step is performed.
In the heavy metal removal device 3 located in the center, the third step is performed, and the iron powder-containing separation 102 separated by the centrifuge 5 is dropped into the heavy metal adsorption water tank 4 of the heavy metal removal device 3 located in the rightmost position. To do. Thereby, the heavy metal removal apparatus 3 located in the center will be in an empty state.
In the heavy metal removal device 3 located on the rightmost side, the iron powder-containing separation product 102 separated in the third step in the heavy metal removal device 3 located in the center is dropped into the empty heavy metal adsorption water tank 4, The contaminated mud water 100 is supplied from the mud tank 2 and the contaminated mud water 100 and the iron powder-containing separated material 102 are mixed (first step).

<6th batch: FIG. 7 (c)>
In the heavy metal removal device 3 located on the leftmost side, the third step is performed, and the iron powder-containing separation 102 separated by the centrifuge 5 is dropped into the heavy metal adsorption water tank 4 of the heavy metal removal device 3 located in the center. To do. As a result, the heavy metal removing device 3 located on the leftmost side is in an empty state.
In the heavy metal removal device 3 located in the center, the iron powder-containing separation 102 separated in the third step in the heavy metal removal device 3 located on the leftmost side is dropped into the empty heavy metal adsorption water tank 4, The contaminated mud water 100 is supplied from the mud tank 2 and the contaminated mud water 100 and the iron powder-containing separated material 102 are mixed (first step).
In the heavy metal removing device 3 located on the rightmost side, the second step is performed.

  Hereinafter, in the seventh batch to the ninth batch, when the number of diversions of the iron powder 10 included in the iron powder-containing separated product 102 reaches the upper limit, or when the contaminated mud 100 to be processed is exhausted, the iron powder-containing separated product is used. This is a disposal preparation stage in which 102 is supplied from the heavy metal removing device 3 to the disposal sludge water tank 8.

<Seventh batch: FIG. 8 (a)>
In the heavy metal removal device 3 located on the leftmost side, after the third step is finished, the empty heavy metal adsorption water tank 4 contains the iron powder separated in the third step in the heavy metal removal device 3 located on the rightmost side. The separated product 102 is dropped (first step).
In the heavy metal removing device 3 located in the center, the second step is performed.
In the heavy metal removing device 3 located on the rightmost side, the third step is performed, and the iron powder-containing separation 102 separated by the centrifugal separator 5 is placed in the heavy metal adsorption water tank 4 of the heavy metal removing device 3 located on the leftmost side. Drop it. As a result, the heavy metal removing device 3 located on the rightmost side is in an empty state.

<Eighth batch: FIG. 8 (b)>
In the heavy metal removing device 3 located on the leftmost side, the waste sludge tank 8 containing the iron powder-containing separated material 102 (including the first iron powder 10) stored in the heavy metal adsorption tank 4 is passed through the fourth sludge pipe 43. To discharge. At this time, when the iron powder-containing separated product 102 cannot be pumped, it is appropriately added to make a solution to adjust the viscosity.
In the heavy metal removal device 3 located in the center, the third step is performed, and the iron powder-containing separation 102 separated by the centrifuge 5 is dropped into the heavy metal adsorption water tank 4 of the heavy metal removal device 3 located in the rightmost position. To do. Thereby, the heavy metal removal apparatus 3 located in the center will be in an empty state.
In the heavy metal removing device 3 located on the rightmost side, the iron powder-containing separated product 102 separated in the third step in the heavy metal removing device 3 located in the center is dropped into the empty heavy metal adsorption water tank 4. In the case where the dropped iron powder-containing separated product 102 has such a viscosity that it cannot be pumped, it is appropriately hydrated to form a solution to adjust the viscosity.

<9th batch: FIG. 8 (c)>
In the heavy metal removal device 3 located on the rightmost side, the iron powder-containing separated product 102 is supplied to the heavy metal adsorption water tank 4 of the heavy metal removal device 3 located on the leftmost side through the centrifugal separator 5. As a result, the heavy metal removing device 3 located on the rightmost side is in an empty state.

  Finally, in the heavy metal removing device 3 located on the leftmost side, the iron powder-containing separated material 102 (including the second iron powder 10) stored in the heavy metal adsorption water tank 4 is discharged to the waste sludge water tank 8.

  In the present embodiment, since only the heavy metal adsorption water tank 4 of the heavy metal removing device 3 located on the leftmost side is connected to the waste sludge water tank 8 via the fourth sludge pipe 43, the processing of the ninth batch is required. However, the heavy metal adsorbing water tank 4 of all heavy metal removing devices 3 may be connected to the waste sludge water tank 8, and in this case, the processing of the ninth batch is unnecessary.

  In this way, three or more heavy metal removing devices 3 are arranged so that the step performed by the heavy metal removing device 3 located on the downstream side with respect to the heavy metal removing device 3 located on the upstream side is a step preceding one step. Shift the work processes to be performed one by one. By carrying out like this, from the heavy metal removal apparatus 3 located in the upstream which is implementing the 3rd process to the heavy metal adsorption tank 4 of the heavy metal removal apparatus 3 located in the downstream which is implementing the 1st process in the same batch The iron powder-containing separated product 102 separated by specific gravity can be dropped, and the working time can be shortened by efficiently circulating the iron powder 10 while repeatedly using it.

  When two flows of iron powder 10 are provided in the contaminated soil cleaning facility 1 and this operation is continued in each system, all three heavy metal removing devices 3 can be operated simultaneously, and iron powder is more efficiently processed. It becomes possible to purify the contaminated mud water 10 using 10. Moreover, even if two flows of the iron powder 10 are provided in the contaminated soil cleaning equipment 1, the two iron powders 10 are not mixed with each other as can be seen from FIGS.

  In the present embodiment, the case where there are three heavy metal removal devices 3 is taken as an example, but in the case of four, as shown in FIG. 9, the contaminated mud water 100 and the iron powder-containing separator 102 are stirred and mixed. A method of ensuring a long time for adsorbing heavy metal in the contaminated mud water 100 to the iron powder 10 contained in the iron powder-containing separated product 102 can be adopted.

  That is, paying attention to the heavy metal removing device 3 located at the leftmost in FIG. 9, in FIG. 9A, the heavy metal located at the rightmost is simultaneously supplied to the heavy metal adsorption water tank 4 from the mud tank 2 at the same time. The 1st process in which the iron powder containing separated substance 102 isolate | separated at the 3rd process of the removal apparatus 3 is dropped is implemented.

  Next, in FIG. 9B, the contaminated mud water 100 stored in the heavy metal adsorption water tank 4 and the iron powder-containing separator 102 are stirred and mixed by the stirring device 41, and the iron powder 10 contained in the iron powder-containing separator 102 is mixed. A second step is performed in which the heavy metal in the contaminated mud water 100 is adsorbed to produce the iron powder-added mud water 101. Further, in FIG. 9C, the second step is continued.

  Then, in FIG. 9 (d), a third step is performed in which the iron powder-added mud water 101 is supplied to the centrifuge 5 and separated into the iron powder-containing separated product 102 and the cleaning mud water 103. In this case, as can be seen from FIG. 9, the iron powder 10 is added to three of the four heavy metal adsorption water tanks 4, and therefore there are three flows of the iron powder 10. ing.

  As described above, when the second step is performed continuously for two batches, it is possible to ensure a long time for the heavy metal in the contaminated mud water 100 to be adsorbed on the iron powder 10 without reducing the overall work efficiency. Therefore, if the number of heavy metal removal devices 3 is increased or decreased according to the type of heavy metal contained in the contaminated mud water 10 to be cleaned and the properties of the contaminated mud water 10 and the number of continuous times of the second process is adjusted, the second step is more reliably performed. It becomes possible to adsorb and fix fine particles of heavy metal on the iron powder 10.

  By the way, the contaminated soil washing | cleaning equipment 1 has the structure in which an administrator can perform remote operation with the terminal device 90 installed in the management office etc. of a construction site.

  As shown in FIG. 1, the terminal device 90 is a so-called personal computer including at least an information processing device 91, an input device 92, and an output device 93. The information processing device 91 includes hardware such as an arithmetic processing device and a storage device, It consists of software that runs on hardware. The mud tank 2, the three heavy metal removing devices 3, the cleaning mud tank 6, the iron powder tank 7, the waste sludge water tank 8, and the iron powder separator 9 are connected in communication.

  And in the information processing apparatus 91 of the terminal device 90, the program which assists operation for performing four processes (s1-s4) for implementing the cleaning method of the contaminated soil mentioned above in the contaminated soil cleaning equipment 1 Is stored. At the same time, an automatic control unit 911 that controls the contaminated soil cleaning facility 1, an iron powder management unit 912 that manages the iron powder 10 supplied from the iron powder tank 7, and a batch processing time in the cleaning process step (s2) of contaminated mud water are notified. And a muddy water monitoring unit 914 for monitoring the contaminated muddy water 100 in the muddy water tank 2.

  The automatic control unit 911 includes at least a valve control function for controlling the opening and closing of the electromagnetic valves provided in each of the first to fourth drainage pipes 22, 42, 51 and 43, and the operation of the pump accompanying the opening and closing of the electromagnetic valves. And a stirring control function for controlling the operation of the stirring device 42 provided in the heavy metal adsorption water tank 4. And according to the four processes (s1 to s4) described above, the opening and closing of the electromagnetic valve, the operation of the pump, and the operation of the stirring device 42 are controlled. In the present embodiment, each of the first to fourth drainage pipes 22, 42, 51, 43 is provided with an electromagnetic valve. However, the present invention is not limited to this, and an automatic valve such as an electric valve or an air valve may be used. Any valve may be used.

  The iron powder management unit 912 counts, for example, the number of times of performing the second step in each of the three heavy metal removing devices 3 as the number of times of diversion of the iron powder 10 in the contaminated mud washing process (s2). It has a function. In addition, a preset number of warnings related to diversion of the iron powder 10 is stored, and a diversion number warning signal is output to the output device 93 when the number of diversions of the iron powder 10 reaches the number of warnings.

  The time notification unit 913 stores a processing time necessary for one batch of the first to ninth batches in the contaminated mud water cleaning process (s2). Then, every time the processing time elapses from the start of processing of the first batch, a time notification signal is output to inform the output device that the processing time has elapsed. The processing time for one batch may be set according to any standard, but the second of the first to third steps performed by each of the three heavy metal removing devices 3 during one batch. Since this process takes the most time, the time required to implement the second process may be set as the processing time for one batch.

  The muddy water monitoring unit 914 has a specific gravity detection function for detecting the specific gravity of the contaminated mud water 100 and a liquid level detection function for detecting the liquid level of the contaminated mud water 100 in the muddy water tank 2. Then, an upper limit value of the specific gravity related to the contaminated mud 100 set in advance is stored, and a specific gravity warning signal is output to the output device 93 when the specific gravity exceeds the upper limit value. Further, the lower limit liquid level of the contaminated mud water 100 in the mud tank 2 is set and stored, and when the liquid level in the mud tank 2 reaches the lower limit liquid level, a liquid level warning signal is output to the output device 93.

  As a result, when the automatic control unit 911 detects the operation start signal of the contaminated soil cleaning facility 1 from the input device 92, the automatic control unit 911 executes the pretreatment step s1, and the muddy water monitoring unit 914 manages the specific gravity of the contaminated mud water 100 and the contamination. The liquid level management of the muddy water 100 is started, and if the specific gravity warning signal and the liquid level warning signal are not output, the process proceeds to the contaminated mud water cleaning process step s2.

Then, the automatic control unit 911 starts the first batch process (FIG. 6A) in the contaminated mud water cleaning process step s 2, manages the number of diversions of the iron powder 10 by the iron powder management unit 912, and reports the time. The processing time management by the unit 913 is started.
Specifically, with the valve control function and the pump control function, the electromagnetic valve of the first mud drain pipe 22 connecting the mud tank 2 and the heavy metal adsorption water tank 4 located at the leftmost is opened and the pump is operated. To do. Further, iron powder is dropped from the iron powder tank 7 into the heavy metal adsorbing water tank 4 located at the leftmost position. Thereafter, when the time notification signal is output from the time notification unit 913 to the output device 93, this is detected, and the valve control function and the pump control function are used to close the electromagnetic valve and stop the pump operation. The process for one batch is terminated and the process for the second batch is started.

  In the processing of the second batch (FIG. 6B), the automatic control unit 911 uses the valve control function and the pump control function to connect the muddy water tank 2 and the heavy metal adsorption water tank 4 positioned at the rightmost position. The electromagnetic valve of the mud pipe 22 is opened and the pump is operated. Moreover, the iron powder 10 is dropped from the iron powder tank 7 into the heavy metal adsorption water tank 4 positioned at the rightmost position. Furthermore, the stirring device 41 of the heavy metal adsorption water tank 4 in the heavy metal removing device 3 located at the leftmost is operated by the stirring control function. Thereafter, when the time notification signal is output from the time notification unit 913 to the output device 93, this is detected, and the valve control function and the pump control function are used to close the electromagnetic valve and stop the pump operation. The operation of the stirring device 41 is stopped by the stirring control function. Then, the process of the second batch is finished and the process of the third batch is started.

  In the processing of the third batch (FIG. 6C), the automatic control unit 911 uses the valve control function and the pump control function to connect the mud tank 2 and the heavy metal adsorption water tank 4 located in the center to the first waste mud. The solenoid valve of the pipe 22 is opened and the pump is operated. Moreover, while opening the electromagnetic valve of the 2nd waste mud pipe 42 which connects the heavy metal adsorption water tank 4 and the centrifuge 5 located in the leftmost, a pump is operated. Further, the electromagnetic valve of the third mud drain pipe 51 connecting the centrifugal separator 5 and the washing mud tank 8 is opened and the pump is operated. Moreover, the stirring apparatus 41 of the heavy metal adsorption | suction water tank 4 located in the rightmost is operated with a stirring control function.

  Thus, every time the time management signal output from the time notification unit 913 is detected, the process proceeds to the sixth batch (FIG. 8C), and thereafter, the process from the fourth batch to the sixth batch ( FIG. 8A to FIG. 8C are repeated.

  And when the automatic control part 911 detects the diversion frequency warning signal of the iron powder 10 or the liquid level warning signal of the muddy water tank 2 in the middle of the above process, the fourth process is performed to end the process of the contaminated muddy water cleaning process s2. The repetition of the processing from the batch to the sixth batch is finished, and the processing according to the processing from the seventh batch to the ninth batch is advanced. After this, the iron powder-containing separated disposal process s3 for discarding the iron powder 10 as the final iron powder-containing separated 104 is started.

  As described above, the contaminated soil cleaning facility 1 can be automatically controlled by the terminal device 90, but at least the control performed by the automatic control unit 911 is performed by the administrator via the input device 92. It goes without saying that it can be carried out manually.

  According to the method for cleaning contaminated soil of the present invention, the iron powder 10 circulates through the three or more heavy metal removing devices 3 in order, without sleeping, while adsorbing the heavy metals contained in the washing mud 100 in each heavy metal removing device 3. To do. As a result, work efficiency can be improved and work time can be greatly shortened.

  The contaminated soil cleaning facility 1 and the contaminated soil cleaning method 1 using the contaminated soil cleaning facility 1 are not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. Needless to say.

DESCRIPTION OF SYMBOLS 1 Contaminated soil washing | cleaning equipment 2 Mud tank 21 Specific gravity detector 22 1st drainage pipe 3 Heavy metal removal apparatus 4 Heavy metal adsorption tank 41 Stirrer 42 2nd drainage pipe 43 4th drainage pipe 5 Centrifuge 51 1st 3 Mud pipe 6 Cleaning mud tank 7 Iron powder tank 8 Waste sludge tank 9 Iron powder separator 10 Iron powder 100 Contaminated mud water 101 Iron powder added mud water 102 Iron powder containing separator 103 Cleaning mud water 104 Final iron powder containing separator 50 Mud treatment facility 501 Solid-liquid separator 502 Adjustment tank 503 Surplus mud tank 60 Shield excavator 61 Pressure chamber 90 Terminal device 91 Information processing device 92 Input device 93 Output device 911 Automatic control unit 912 Iron powder management unit 913 Time notification unit 914 Mud water Monitoring unit

Claims (5)

The contaminated mud containing contaminated soil contaminated with heavy metals is stored, the mud tank that manages and adjusts the specific gravity of the contaminated mud, and the contaminated mud supplied from the mud tank is washed with iron powder to remove the heavy metals A contaminated soil cleaning facility comprising three or more heavy metal removing devices for producing the washed mud, and a washing mud tank for storing the washed mud discharged from each of the heavy metal removing devices,
A heavy metal adsorption tank in which the heavy metal removing device stirs and mixes the contaminated mud water and the iron powder to adsorb the heavy metal in the contaminated mud water to the iron powder, and the heavy metal adsorption tank A centrifuge that separates the iron powder-added muddy water into the washing muddy water and the iron powder-containing separated containing the iron powder that has adsorbed the heavy metal, and a centrifuge.
Three or more heavy metal removal devices having the specific gravity separated by the centrifugal separator of the heavy metal removal device located on the upstream side are directly dropped into the heavy metal adsorption tank of the heavy metal removal device located on the downstream side. The contaminated soil cleaning facility is characterized by being arranged to form a circulation path for the iron powder. In the contaminated soil cleaning facility according to claim 1,
Of the three or more heavy metal removing devices, the heavy metal adsorption tank provided in at least one heavy metal removing device is connected to a waste sludge water tank for discarding the iron powder-containing separation. Cleaning equipment. The contaminated soil cleaning equipment according to claim 1 or 2,
An automatic valve and a pump for supplying a polluted mud from the mud tank to each of the heavy metal adsorbing tanks and a mud pipe for supplying the iron powder added mud from the heavy metal adsorbing tanks to the centrifuge, respectively. However, an automatic valve is provided in the mud pipe for supplying the washing mud from the centrifuge to the washing mud tank,
A contaminated soil washing facility, comprising a terminal device for controlling the opening and closing of the automatic valve and the operation of the pump associated therewith. A method for cleaning contaminated soil using the contaminated soil cleaning facility according to any one of claims 1 to 3,
In each of the heavy metal removing devices, in the heavy metal adsorption tank, the first step of mixing the muddy water and the iron powder or the iron powder-containing separated material, mixing the muddy water and the iron powder or the iron powder-containing separated material. The second step of producing the iron powder-added mud while stirring and adsorbing the heavy metal in the contaminated mud to the iron powder or the iron powder contained in the iron powder-containing isolate, and the iron powder-added mud While supplying to the centrifuge from the heavy metal adsorption tank, repeatedly performing a third step of specific gravity separation into the washing muddy water and the iron powder-containing separation,
The work process performed simultaneously in each of the at least three heavy metal removing apparatuses is performed so that the process performed in the heavy metal removing apparatus located on the downstream side with respect to the heavy metal removing apparatus located on the upstream side is a process preceding one process. Shift one by one,
The iron powder-containing separation separated by specific gravity from the heavy metal removal device located upstream in the third step is dropped into the heavy metal adsorption tank in the heavy metal removal device located downstream in the first step. A method for cleaning contaminated soil, characterized by In the cleaning method for contaminated soil according to claim 4,
After performing the said 2nd process continuously several times, it transfers to a 3rd process, The cleaning construction method of the contaminated soil characterized by the above-mentioned.