JP2003071428A - Method and apparatus for treating polluted soil or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To treat polluted soil or sludge without causing pollutants, treated water, odors, etc., to escape or leak therefrom. SOLUTION: In an apparatus 10 for treating polluted soil, the polluted soil or the like is heated to at least 450 deg.C in a reducing atmosphere in a heat treatment furnace 12 to treat dioxins, etc.; the treated soil or the like is suspended in diluting water in a dilution apparatus 14; the earth or the like is separated and recovered from the slurry by being passed through a separator 16; ozone is added from an ozone addition apparatus 18; electrolysis and reduction are simultaneously performed by an electrolytic reduction apparatus 20 to separate the water from various substances; and the remainder of the treated water is sent again to the apparatus 14 and is used as diluting water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for treating contaminated soil contaminated with dioxin or the like, or sludge as industrial waste.

[0002]

2. Description of the Related Art It is known that soil and ash contaminated with dioxins and the like can be decomposed by causing a dechlorination chemical reaction when heated to 450 ° C. or higher in a reducing atmosphere.

Further, it is known that sludge of various organic industrial wastewater discharged from food factories, organic wastewater sludge made of manure of cattle, pigs, etc. is dehydrated to reduce its volume. There is.

[0004]

As described above, the dioxin can be decomposed by heating the contaminated soil to some extent, but the contaminated soil often contains heavy metals, and therefore the dioxin is directly contained in the contaminated soil. There is a problem that it cannot be returned or discarded.

[0005] Further, even if the sludge of various organic industrial wastewater is dehydrated, it is necessary to incinerate it at the end, and further to treat the incinerated ash by melting and solidifying.

In any of the above cases, a large amount of energy is required for the treatment, the odor control is insufficient, and further, the water content after sludge separation is reused,
There was a problem that it could not be discharged to the river as it was.

Furthermore, in order to treat the contaminated soil and sludge, these must be transported to a treatment facility, and in the process, a large transportation cost is required, and leakage or odor during transportation is required. There are various problems that may occur.

The present invention has been made in view of the above-mentioned problems of the prior art, and does not consume much energy, has a low running cost, and the polluted soil after decomposing dioxins and the like contains heavy metals. The object of the present invention is to provide a method and an apparatus for treating contaminated soil, etc., which can be reused except for sludge and whose water content can be reused.

Another object of the present invention is to provide a method and an apparatus for treating contaminated soil or the like, which does not require transportation of the contaminated soil or the like to the treatment device during treatment.

[0010]

The present invention provides a heat treatment step of heating at least one of sludge soil and sludge to 450 ° C. or higher in a reducing atmosphere, and a product of the heat treatment step in diluted water. A charging step of charging, a discharging step of discharging a cooled solid matter from the diluted water, a precipitation step of precipitating particles suspended in the diluted water after exposing the solid matter, and the precipitation An ozone addition step of adding ozone to the dilution water after separating the precipitate in the step to generate emulgen particles, and electrolyzing the ozone-added dilution water to generate metal ions and hydroxide ions, and The emulsion particles in water are neutralized with a metal ion, and the metal ion is reduced with the hydroxide ion to produce a metal hydroxide, and the neutralized emulsion. Electrolytic reduction step of aggregating particles and metal hydroxide, a separation step of separating the agglomerates in this electrolytic reduction step, and the treated water after separating the agglomerates in this electrolytic reduction step is diluted as described above. The above object is achieved by a method for treating contaminated soil and the like, which comprises a circulation step of supplying as a part of water.

In the method for treating contaminated soil or the like, the electrolytic reduction step includes an electrolysis step of applying a direct current to the dilution water, and an ozone removal step of removing ozone from the dilution water that has undergone the electrolysis step. An aggregation step of aggregating the emulsion particles in the diluted water and the metal hydroxide that have undergone the ozone removal step may be included.

Furthermore, in the method for treating contaminated soil, etc.,
The agglomerates in the electrolytic reduction step and the separation step may be put into the heat treatment step and heated together with at least one of the contaminated soil and sludge.

Further, in the method for treating contaminated soil, etc.,
The heat treatment step, the charging step and the discharging step are performed in the first container loaded on the first trailer, and the precipitation step, the ozone addition step, the electrolytic reduction step and the separation step are adjacent to the first trailer. Is carried out in a second container loaded on a second trailer, the dilution water in the charging step is sent to a precipitation step carried out in the second container, and the circulating step is carried out in the second container. You may make it execute from the container of 1 to the 1st container.

Further, in the method for treating contaminated soil or the like, the electric power required in each of the steps may be supplied from a generator mounted on a vehicle separate from the first and second trailers. good.

The apparatus of the present invention comprises a heat treatment furnace capable of heating contaminated soil, sludge and the like in a reducing atmosphere at 450 ° C. or higher, and a water tank filled with dilution water, and heated in the heat treatment furnace. A solid material after is charged, at least a part of the charged processed material is suspended in particles in the dilution water, and a diluting device adapted to take out unsuspended solid matter from the dilution water, A separation device for separating a part of the suspended particles from the dilution water after taking out the solid matter, and adding ozone to the dilution water from the separation device, or adding water to which ozone is added. An ozone addition device that generates emulsion particles and electrolysis is performed by applying a direct current to the ozone-added dilution water, eluting metal ions in the electrolyzed water and generating hydroxide ions, and electrolyzing with the metal ions. Emma in the water Electrolysis reduction apparatus for neutralizing John particles and neutralizing metal ions with the hydroxide ions to generate metal hydroxides, and an aggregating apparatus for aggregating the neutralized emulsion particles and metal hydroxides And a treated water circulation system for circulating treated water separated from agglomerates in the aggregating device to a water tank of the diluting device, thereby further achieving the above object by a treating device for contaminated soil or the like. .

In the apparatus for treating contaminated soil or the like, the electrolytic reduction apparatus comprises perforated electrodes arranged at both axial ends of a tubular perforated plate made of an insulating material, and the electrodes are provided between these electrodes. It may be configured to accommodate a metal pellet which is a material of metal ions.

Further, in the above-mentioned apparatus for treating contaminated soil,
The metal pellet may be an aluminum pellet.

Furthermore, in the apparatus for treating contaminated soil or the like, the electrolytic reduction apparatus has the electrodes in the vertical direction,
The upper electrode is used as an anode and the lower electrode is used as a cathode and is placed in an electrolytic cell. This electrolytic cell has a lower position than the lower electrode, an inlet for the dilution water to flow in, and an overflow at the upper end. Each mouth may be provided.

Further, in the apparatus for treating contaminated soil or the like, the aggregating apparatus may include an ozone removing apparatus for removing ozone in the diluting water that has passed through the electrolytic reduction apparatus.

Furthermore, in the treatment apparatus for the contaminated soil, etc.,
The ozone removing device may include activated carbon, and the activated carbon may adsorb ozone.

Further, in the apparatus for treating contaminated soil and the like, the first container is loaded on the first trailer, the first container is loaded with the heat treatment furnace and the diluter, and the second container is loaded on the second container. A second container equipped with a separation device, the ozone addition device, the electrolytic reduction device, and the aggregating device is provided, and the first and second devices are provided.
The diluting water pipe and the treated water circulating system that interlock the diluting device and the separating device may be detachably arranged between the containers.

In the present invention, by heating the contaminated soil or the like to 450 ° C. or higher in a reducing atmosphere to decompose dioxins, the treated product is put into the diluting water to obtain a solid substance which is not suspended in the diluting water. There are separated stones, sand, glass, metal pieces, etc.

Further, the earth suspended in the form of particles in the diluting water is recovered by being precipitated and separated in the precipitation step. The remaining dilution water is deodorized by the addition of ozone, and by applying a DC voltage to the ozone-added dilution water, metal ions and hydroxide ions are generated by electrolysis, and metal ions and hydroxide ions are used to generate metal ions. The treated water after forming the hydroxides, aggregating them and separating the agglomerates is circulated to the first step as dilution water. During electrolysis, even if heavy metals are dissolved in the diluted water, they become metal ions and are further aggregated and recovered as metal hydroxides.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, in a contaminated soil treatment apparatus 10 according to an example of this embodiment, a superheat treatment furnace 12 and a processed material after being heat-treated in the superheat treatment furnace 12 are charged. Diluting device 14 and separating device 16 for separating particles suspended in the diluting water from the diluting device 14.
An ozone addition device 18 for adding ozone to the dilution water from the separation device 16; an electrolytic reduction device 20 for applying a direct current to the dilution water to which ozone is added by the ozone addition device 18 for electrolysis; An aggregating device 21 for aggregating and separating metal hydroxides and the like generated in the electrolytic reduction device 20, and a treated water circulation system 22 for returning the treated water after removing the agglomerates to the diluting device 14 as dilution water.
And are provided.

As shown in FIG. 2, the heat treatment furnace 12 and the diluting device 14 are mounted in a first container 26 loaded on a first trailer 24, and the separating device 16, Ozone addition device 18, electrolytic reduction device 20
Are loaded in the second container 30 loaded on the second trailer 28.

The treated water circulation system 22 includes a pipe 23B provided with a pump 23A for pumping the treated water and a valve 23C provided in the middle of the pipe 23B. The pipe 23B, which is mounted on the container 26 and includes the valve 23C, is provided between the first container 26 and the second container 32.

Reference numeral 32 in FIGS. 2 and 3 indicates a tractor for towing the first and second trailers 24, 28, respectively. Reference numeral 34 in FIGS. 2 and 3 indicates a charging hopper. Contaminated soil and sludge are charged into the charging hopper 34 by a shovel car 36, and the heat treatment is performed by a conveyor 38 from the lower end of the charging hopper 34. The furnace 12 is designed so that it can be conveyed to the charging port 12A (see FIG. 1) and charged.

Further, as shown in FIG. 2, a generator 40 for supplying necessary electric power and compressed air to the polluted soil treatment apparatus 10 mounted on the first and second containers 26 and 30. The compressor 41 is mounted on a truck 42 separate from the first and second trailers 24, 28 and the tractor 32.

Next, the furnace and each device constituting the contaminated soil treatment device 10 will be described in detail.

As shown in FIGS. 4 and 5, the heat treatment furnace 12 is a rotary kiln type heat treatment furnace having a horizontally arranged cylindrical rotary cylinder 44.

The rotary cylinder 44 is supported by six support rollers so as to be rotatable about a horizontal center axis of rotation.
While rotating the contaminated soil and the like introduced from above the one end of the cylinder through the charging port 12A to the opposite end, while heating it to 450 ° C. or higher by the electric heater 46,
The rotary cylinder 44 is discharged from an outlet 12B provided on the lower side of the end opposite to the inlet 12A.

Both ends of the rotary cylinder 44 are substantially closed so that contaminated soil or the like is heated in a reducing atmosphere inside.

In the electric heater 46, the central portion of the cylindrical rotary cylinder 44 is fixed to the rotary cylinder 44.
And a pipe 46A made of, for example, stainless steel, which is rotatably mounted through the pipe and the pipe 4A.
A heating element 46 that is provided inside 6A and that generates heat when energized
B and a slip ring 46C attached to the pipe 46A at a position projecting from the rotary cylinder 44 so that electric power can be introduced while rotating with the rotary cylinder 44.
And is configured.

Inside the rotary cylinder 44, a feed screw 45B is provided spirally around the electric heater 46 so that the rotary cylinder 44 rotates together with the electric heater 46.
The polluted soil and sludge put into the inside are sent while rotating toward the outlet 12B.

Reference numerals 45C in FIGS. 4 and 5 are ring-shaped rails mounted on the outer periphery of the rotary cylinder 44 so as to be in rolling contact with the support rollers 45A, and 45D is a rotary rail other than the ring-shaped rail 45C. The heat insulating material which is attached so as to cover the outside of the cylindrical body 44 is shown. Further, reference numeral 48 in FIG. 4 denotes a gas vent for recovering a gas component generated from the treated contaminated soil or the like by covering the outlet 12B and the axial end surface of the rotary cylinder 44 adjacent to the outlet 12B. Indicates a space. A condenser 48B and a drain tank 48C are connected to the degassing space 48 via a degassing pipe 48A so that water vapor or the like generated in the rotary cylinder 44 can be condensed and collected as drain in the drain tank 48C. Has been done.

Reference numeral 49 in FIGS. 4 and 5 indicates a support roller 4 for supporting the intermediate position of the rotary cylinder 44 in the axial direction.
5A shows a motor for driving 5A to apply a rotational force to the rotary cylinder 44.

The diluting device 14 includes a water tank 14A and a cylinder having both ends opened, which is rotatably provided around a horizontal center axis of rotation in a state where the lower half of the diluting water in the water tank 14A is submerged. And a diluting rotary 14B having a shape.

The dilution rotary 14B has a diameter of 0.
The wire net is formed with a large number of 3 mm pores, and is horizontally driven by the support roller 15A and about the horizontal rotation center axis.

Further, from the opening on one side in the axial direction of the cylindrical dilution rotary 14B, by the conveyor 15B,
Heat-treated contaminated soil, sludge and the like discharged from the outlet 12B of the heat treatment furnace 12 are carried into the dilution rotary 14B.

Further, a water sprinkling pipe 15C is axially long at the upper end position in the dilution rotary 14B, and the treated water supplied from the treated water circulation system 22 can be sprinkled in the dilution rotary 16B as dilution water. Is being done.

Reference numeral 15D in FIG. 1 denotes a drive roller provided so as to be in rolling contact with the upper end position of the dilution rotary 14B. The drive roller 15D is rotated by a motor 15E so as to drive the dilution rotary 14B to rotate. Has become.

Reference numeral 15F in FIG. 1 indicates stones, gravel, glass, etc. accumulated in the water tank 14A without being suspended in the dilution water.
1 shows a discharge conveyor for discharging solid matter such as metal pieces.

The separating device 16 is a water cyclone 16A.
And a settling tank 16B.
The dilution water in which the heat-treated particle-like contaminated soil and the like are suspended from the water tank 14A is supplied to the water cyclone 16A through the pipe 16C.

An on-off valve 15G and a pump 16D are arranged in this order in the pipe 16C between the water tank 14A and the water cyclone 16A. A pump 16E is also arranged in a pipe 16C between the water cyclone 16A and the settling tank 16B.

The water cyclone 16A rotates the dilution water in a vortex inside thereof to separate the particulate solid matter by centrifugal force, and the separated solid matter can be discharged from the lower discharge valve 15F. Is being done.

The settling tank 16B has a water cyclone 16
The dilution water containing the particulate solid matter not separated in A is fed by the pump 16E.

In the settling tank 16B, while the diluting water slowly flows through the inside of the settling tank 16B, the particulate solid matter is settled downward and discharged from the discharge valve 16G below.

The ozone addition device 18 is used in the precipitation tank 1
Ozone is added by blowing ozone gas into the diluted water from 6B, and when the concentration of the suspension in the diluted water from the settling tank 16B is high and the water content is low, the ozone addition is insufficient. After fresh water is added to the dilution water from the water tank 50, ozone is added in the ozone addition device 18, whereby emulsion particles are generated.

The dilution water containing ozone is cooled by the cooler 19
The heat is dissipated, the temperature is raised to room temperature, and then the temperature is sent to the electrolytic reduction apparatus 20.

This electrolytic reduction device 20 applies direct current to the ozone-added dilution water to electrolyze it, elutes metal ions in the electrolyzed water and produces hydroxide ions, which are electrolyzed by the metal ions. The emulsion particles in water are neutralized, and at the same time, the metal ions are neutralized by the hydroxide ions to produce metal hydroxide.

In this electrolytic reduction apparatus 20, perforated plate-shaped electrodes 20C and 20D are arranged at both ends of a vertically long cylindrical member 20B provided in an electrolytic cell 20A, and an upper electrode 2
DC is applied from the DC power supply 21 so that 0C serves as an anode and the lower electrode 20D serves as a cathode.

The cylindrical member 20B is formed by forming a large number of holes in a plate-shaped insulating material such as vinyl chloride, and a metal pellet 20E such as alumina is housed between the perforated plate-shaped electrodes 20C and 20D. is doing. An inlet 20F into which the ozone-added dilution water flows into the electrolytic cell 20A at a position lower than the electrode 20D, and the back electrode 2
At the upper end of the electrolytic cell 20A, which is located at a position higher than 0C, outlets 20G are provided for the electrolytically diluted water to overflow.

Further, a sludge discharge valve 20H is provided at the lower end of the electrolytic cell 20A.

From the upper end of the electrolytic cell 20A, the first flocculation-precipitation tank 53A and the second flocculation-precipitation tank 53B of the flocculation device 52 are provided.
It is supposed to flow down to.

The ozone removing device 21 is arranged in the first coagulating sedimentation tank 53A, and the second coagulating sedimentation tank 53B.
As the material, zeolite, carbonized ceramics, or the like is used.

These first and second coagulating sedimentation tanks 53A, 5
3B is a partition wall 5 extending downward from the upper end.
3C, the dilution water flowing from the upper end passes through the lower end of the partition wall 53C, returns to the upper end on the opposite side, overflows, and is discharged.

Furthermore, these first and second coagulating sedimentation tanks 53
Sludge discharge valves 53D are provided at the lower ends of A and 53B, respectively. The ozone removing device 21 is made of, for example, activated charcoal charcoal or bamboo charcoal and adsorbs ozone.

The first coagulation and sedimentation tank 50B of the first
From the upper end on the side opposite to the coagulation-sedimentation tank 53A, oil, sludge, dust, etc. floating from the dilution water overflows from the sludge collection port 53E and is collected in the sludge tank 53F.

Further, a pipe 23B of the treated water circulation system 22 is connected to a position slightly lower than the upper end of the second coagulating sedimentation tank 53B, and the diluting water is treated by the pump 23A as the treated water. It is adapted to be supplied to the water sprinkling pipe 15C.

The sludge collected from the sludge discharge valve 53D and the sludge recovery port 53E in the flocculation device 52, or sludge and dust, and oil are charged into the charging port 12A of the heat treatment furnace 12 for processing.

Further, when the treated water flowing out from the second flocculation-precipitation tank 53B is excessive, it is sent to the treatment tank 54 by the pump 23A, and here, the first and second flocculation-precipitation tank 53.
In the same manner as in A and 53B, the remaining particulate matter is suspended in the treated water to be precipitated, and the precipitate is collected from the sediment collecting valve 54A at the lower end, and is in a state close to the remaining fresh water. The water is discharged or is returned to the upstream side of the ozone adding device 18 through the valve 54B if necessary.

Next, the process of treating contaminated soil, sludge, etc. by the contaminated soil treatment apparatus 10 according to the above-described embodiment will be described.

Usually, soil contaminated with dioxins or the like, or oil sludge as industrial waste is dispersed in various places, and these need to be transported to a treatment plant for treatment, but in the case of the present invention, The entire contaminated soil treatment device 10 is loaded on the first and second trailers 24 and 28 and can be transported by a tractor 32. These are carried together with a truck 42 equipped with a generator 40 and a compressor 41 together with contaminated soil and sludge. It can be installed and run on the spot as it is.

At the time of installation, the first and second trailers 24 and 28 are arranged side by side as shown in FIG. 2, and pipes 16C and 23B are connected between them.

Further, as shown in FIG. 1, a water tank 50 is connected to the first container 26, and the charging hopper 34 is charged into the heat treatment path 12 via a conveyor 38. Installed by connecting to the mouth 12A.

In this state, for example, when treating contaminated soil, the shovel car 36 introduces the contaminated soil into the charging hopper 34 and the conveyor 38 into the charging port 12A of the superheat treatment furnace 12.

In the heat treatment path 12, as the rotary cylinder 44 rotates, the feed screw 45B integrated with the rotary cylinder 44 feeds the contaminated soil and the like from the inlet 12A toward the outlet 12B.

During this period, the electric heater 46 is energized from the slip ring 46C to generate heat from the heating element 46B.
It is heated to 50 ° C or higher. At this time, the rotary cylinder 4
Unless air or the like is supplied to the inside of 4, the inside becomes a reducing atmosphere in which oxygen is blocked, so that dioxins contained in contaminated soil are decomposed by heating.

The contaminated soil and the like thus heat-treated are discharged from the outlet 12B of the heat treatment path 12 by the conveyor 15B.
It is carried into the diluting rotary 14B in the diluting device 14.

The lower half of the diluting rotary 14B is immersed in the diluting water in the water tank 14, and
4B is suspended in the dilution water from the water sprinkling pipe 15C in the upper part of 4B in the form of fine particles.

At this time, since the dilution rotary 14B is made of a wire mesh material, the dilution water and contaminated soil suspended in the dilution water flow out from the dilution rotary 14B into the water tank 14A.

Gravel, pebbles, glass contained in contaminated soil, etc.
Solids such as metal pieces fall without being suspended in dilution water,
This is discharged to the outside by the discharge conveyor 15F.

Suspended contaminated soil and sludge, or oil contained in the sludge, which has flowed out from the dilution rotary 14B into the water tank 14A, is sent to the water cyclone 16A by the pump 16D through the opening / closing valve 15G.

In the water cyclone 16A, the diluting water makes a swirling motion by centrifugal force, whereby it is separated into a liquid portion and a solid matter, and solid matters such as soil are separated from the water cyclone 16A.
It is appropriately discharged from the discharge valve 16F at the lower end. The remaining dilution water is sent to the settling tank 16B by the pump 16E.

In the settling tank 16B, the diluting water slowly flows through the settling tank 16B, so that soil and the like are settled downward and separated, and discharged from the discharge valve 16G at the lower end.

The soil and the like discharged from the discharge valves 16F and 16G are returned to the original state because the contaminants have been removed.

On the other hand, the separated dilution water is sent to the ozone addition device 18, where the ozone gas is added. At this time, when the water content of the diluted water from the settling tank 16B is small, fresh water is supplied from the water tank 50 to secure the optimum water content for ozone addition.

Here, in the ozone adding device 18,
The ozone concentration is 200 to 50,000 ppm.

When ozone is added, emulsion particles are generated in the treated water and the odor is removed by ozone. The dilution water containing the emulsion particles is
Heat is radiated by the next cooler 19 and cooled to the atmospheric temperature.

Next, the dilution water is supplied to the electrolytic cell 20A in the electrolytic reduction apparatus 20. Electrodes 20C and 20B are arranged at both ends of the cylindrical member 20B in the electrolytic cell 20A,
A DC voltage is applied with the upper electrode 20C as an anode and the lower electrode 20D as a cathode, and the metal pellets 20E made of alumina are filled in the interior. It is decomposed and aluminum ions are eluted in the electrolyzed water. Further, hydroxide ions are generated on the cathode (electrode 20D) side.

Furthermore, the generated aluminum ions neutralize the emulsion particles in the electrolyzed water, and at the same time,
The hydroxide ions generated at the cathode neutralize the metal ions to produce metal hydroxide (aluminum hydroxide). That is, electrolysis and reduction are performed in the electrolytic cell 20A.

Even if heavy metals are dissolved in the diluted water, they are converted to metal ions by electrolysis and treated in the same manner as aluminum ions to form metal hydroxides.

The process of ozone addition and electrolytic reduction will be described in more detail. When diluting water (sewage) is mixed with ozone-treated water or ozone is directly added to the diluting water, electrolysis is performed with a direct current, whereby substances in the solution are dissolved. Are separated by giving and receiving electrons at the cathode and the electrode, respectively, and the redox product generated at that time causes a secondary reaction with the hydroxide eluted from the electrode to generate an aggregating action.

Trivalent ions Al ³⁺ eluted from the cathode by electrolysis neutralize emulsion particles which are negatively charged by the addition of ozone and are stable in water, while
It reacts with OH ions generated by electrolysis of water to grow particles and become nuclei to generate Al (OH) ³ , which promotes separation and electrolytic reduction.

As a result of this electrolytic reduction, for example, neutralized emulsion particles and metal hydroxide aggregates are generated.
If it occurs in 0A, it causes precipitation and is discharged from the lower sludge discharge valve 20H.

Dilution water is supplied to the electrolytic cell 20A from a position lower than the lower electrode 20D, and the upper end of the electrolytic cell 20A serves as an outlet 20G. The diluted water overflows and flows in from the upper end of the first coagulating sedimentation tank 53A of the adjacent coagulating device 52.

Here, the electrolytically reduced dilution water is
After ozone is adsorbed and removed by the ozone removing device 21 in the first coagulating sedimentation tank 53A, the second coagulating sedimentation tank 53B
During the sequential flow of the above, the neutralized emulsion particles and the metal hydroxide as described above are aggregated and precipitated.
It is discharged from the sludge discharge valve 53D at the lower ends of the first and second coagulating sedimentation tanks 53A and 53B.

Further, the upper end of the final second coagulation-sedimentation tank 53B serves as a sludge recovery port 53E, and the pipe 23B of the treated water circulation system is connected to a position lower than the upper end to coagulate sedimentation from the dilution water. Oil, sludge, dust, etc., floating on the treated water that has been treated, sludge recovery port 53E
Overflows from the sludge and is collected in the sludge tank 53F.

The sludge, oil, dust and the like collected in the sludge discharge valves 20H and 53D and the sludge tank 53F are introduced into the inlet 12A of the heat treatment furnace 12 and are treated again, and are not leaked to the outside. . When the amount of collected oil is large, it is collected in the processed oil tank 56 and separately processed.

The treated water that has flowed out of the second coagulating sedimentation tank 53B is supplied by the pump 23A of the treated water circulation system 22.
It is supplied to the sprinkling pipe 15C in the dilution rotary 14B via the pipe 23B and is used again as dilution water. Therefore, the dilution water does not leak outside. Further, even if the suspension remains in the treated water, it is reused as dilution water, so there is no problem.

If the treated water from the second coagulating sedimentation tank 53B is sprinkled even further from the sprinkling pipe 15C of the dilution rotary 14B, it is supplied to the treating tank 54,
Here, the soil, aggregates, and the like contained therein are slowly precipitated and become treated water that is close to fresh water, and this is recycled to the upstream side of the ozone addition device 18 if necessary.

Further, the precipitate deposited downward in the processing tank 54 is recovered from the precipitation recovery valve 54A and is charged into the charging port 12A of the heat treatment furnace 12 in the same manner as described above.

Therefore, in the contaminated soil treatment apparatus 10 according to the present invention, solid matters such as sand, stones and metals which are not contaminated are separated in the diluting apparatus 14 and the soil and sludge are dissolved or suspended. Treated water is electrolyzed and reduced by direct current voltage in an electrolytic reduction device after sediments such as soil are sequentially separated, various pollutants are treated and recovered as aggregated solids, and treated water is highly treated and then diluted. Since it is reused as water, the pollutant does not leak outside, and the harmless part of the contaminated soil and sludge can be reliably recovered and reused.

In particular, in the example of this embodiment, various devices constituting the contaminated soil treatment device 10 are separately mounted in two containers, and are directly brought to the treatment site for contaminated soil or sludge, and the contaminated soil is treated. Since the soil and sludge can be treated on the spot, it is possible to prevent the contaminated soil and sludge from scattering to the outside during transportation.

In the example of the above-mentioned embodiment, each device constituting the contaminated soil treatment device 10 is mounted on two containers, but the present invention is not limited to this, and for example, all of them can be mounted on a ship. Alternatively, a part thereof may be installed, and further, it may be installed in a processing factory. However, if it is installed in a processing plant, there is a disadvantage associated with transporting contaminated soil.

[0097]

[Example] The BOD value before and after the addition of ozone and the electrolytic reduction of the dilution water was measured using the ozone addition device and the electrolytic reduction device in the polluted soil treatment device, and the results are shown in Table 1.

[0098]

[Table 1]

This was a treatment of sewage from the Onna Village Reservoir in Okinawa Prefecture, and as can be seen from Table 1, a significant improvement was observed in all cases.

When the pig urine in the pig farm was treated in the same manner, the BOD value and the like were significantly reduced as shown in Table 2.

[0101]

[Table 2]

[0102]

Since the present invention is configured as described above, it is excellent in that it is possible to reliably treat contaminated soil and sludge at low cost without leaking pollutants or contaminated treated water to the outside. Have the effect.

[Brief description of drawings]

FIG. 1 is a pipeline diagram including a partial side view showing a contaminated soil treatment device according to an example of an embodiment of the present invention.

FIG. 2 is a schematic plan view showing a state in which the contaminated soil treatment device is mounted on two trailers and a truck.

FIG. 3 is a side view of the same.

FIG. 4 is a sectional view showing a heat treatment device in the contaminated soil treatment device.

5 is a sectional view taken along line VV of FIG.

[Explanation of symbols]

10-Contaminated soil treatment device 12 ... Heat treatment furnace 12A ... Inlet 12B ... Exit 14 ... Diluter 14A ... water tank 14B: Dilution rotary 15B ... Conveyor 15F ... Discharge conveyor 16 ... Separation device 16A ... water cyclone 16B ... Settling tank 16C ... Piping 16D, 16E ... Pump 16F, 16G ... Discharge valve 18 ... Ozone addition device 20 ... Electrolytic reduction device 20A ... electrolytic cell 20B ... Cylindrical member 20C, 20D ... Electrode 20E ... Metal pellets 20F ... Entrance 20G ... Exit 20J ... Direct power supply 21 ... Ozone removal device 22 ... Treated water circulation system 23A ... pump 23B ... Piping 23C ... Valve 24 ... the first trailer 26 ... first container 28 ... second trailer 30 ... second container 32 ... tractor 34 ... Input hopper 36 ... excavator car 38 ... Conveyor 40 ... Generator 41 ... Compressor 44 ... Rotary cylinder 45B ... Feed screw 46 ... Electric heater 52 ... Aggregator 53A ... 1st coagulating sedimentation tank 53B: Second coagulating sedimentation tank 53D: Sludge discharge valve 53E: Sludge collection port 53F ... sludge tank 54 ... Treatment tank 54A ... Sediment recovery valve 54B ... Valve

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 1/465 C02F 1/46 101B 1/78 102 11/00 F term (reference) 4D004 AA02 AA41 AB03 AB07 AC07 CA13 CA22 CA40 CB09 CB32 CB44 CB50 CC03 DA03 DA06 4D050 AA12 AB07 BB02 BD06 CA06 CA10 CA16 4D059 AA03 BB03 BB14 BE31 BE39 BE51 BK06 CA28 CB30 EB06 4D061 DA08 DB15 DB19 DC06 DC20 EA04 EA14 FA16 EB06 FA04 EB06 FA22

Claims (12)

[Claims] 1. A heat treatment step of heating at least one of contaminated soil and sludge to 450 ° C. or higher in a reducing atmosphere, a step of introducing the product of this heat treatment step into diluted water, and a step of introducing the product from the diluted water. From the discharging step of taking out the cooled solid matter and the dilution water after taking out the solid matter,
A precipitation step of precipitating particles suspended in this, an ozone addition step of generating ozone particles by adding ozone to the dilution water after separating the precipitate in the precipitation step, and ozone-added dilution water To generate metal ions and hydroxide ions, neutralize emulsion particles in water with the metal ions, reduce the metal ions with the hydroxide ions to generate metal hydroxide, and An electrolytic reduction step of aggregating the neutralized emulsion particles and a metal hydroxide, a separation step of separating the agglomerates in the electrolytic reduction step, and a step of separating the agglomerates in the electrolytic reduction step A circulating step of supplying treated water as a part of the dilution water, and a method for treating contaminated soil or the like. 2. The electrolytic reduction step according to claim 1,
An electrolysis step of applying a direct current to the dilution water, an ozone removal step of removing ozone from the dilution water that has undergone the electrolysis step, and an aggregation that aggregates emulsion particles and metal hydroxide in the dilution water that has undergone the ozone removal step. A method for treating contaminated soil or the like, which comprises: 3. The pollution according to claim 1, wherein the agglomerates in the electrolytic reduction step and the separation step are put into the heat treatment step and heated together with at least one of the contaminated soil and sludge. How to dispose of soil. 4. The heat treatment step, the charging step, and the discharging step according to claim 1, 2 or 3, which are carried out in a first container loaded on a first trailer, and the precipitation step, the ozone addition step, The electrolytic reduction step and the separation step are executed in a second container loaded on a second trailer adjacent to the first trailer, and the dilution water in the charging step is executed in the second container. A method for treating contaminated soil or the like, which comprises sending to a settling step and performing the circulating step from the second container to the first container. 5. The electric power required for each of the steps is supplied from a generator mounted on a vehicle separate from the first and second trailers. How to treat contaminated soil. 6. Contaminated soil, sludge, etc. in a reducing atmosphere at 450 ° C.
A heat treatment furnace that can be heated as described above, and a water tank is filled with dilution water, and a solid matter after being heated in the heat treatment furnace is charged, and at least a part of the charged treatment product, Suspending particles in the dilution water in the form of particles, a diluting device adapted to remove unsuspended solid matter from the dilution water,
A separation device for separating a part of the suspended particles from the dilution water after taking out the solid matter, and adding ozone to the dilution water from the separation device, or adding water to which ozone is added. An ozone addition device for generating emulsion particles,
A direct current is applied to the dilution water to which ozone is added to cause electrolysis, and metal ions are eluted in the electrolyzed water to generate hydroxide ions, and the emulsion particles in the electrolyzed water are neutralized by the metal ions, An electrolytic reduction device that neutralizes metal ions by the hydroxide ions to produce metal hydroxides, an aggregating device that aggregates the neutralized emulsion particles and metal hydroxides, and an aggregate in the aggregating device And a treated water circulation system for circulating the treated water separated from the above into a water tank of the diluting device. 7. The electrolytic reduction device according to claim 6,
A cylindrical perforated plate made of an insulating material is provided with perforated electrodes at both ends in the axial direction, and metal pellets serving as a material of the metal ions are housed between the electrodes. Equipment for processing contaminated soil. 8. The apparatus for treating contaminated soil according to claim 7, wherein the metal pellet is an alumina pellet. 9. The electrolytic reduction apparatus according to claim 7, wherein the electrodes are arranged in a vertical direction, and the upper electrode is an anode,
The lower electrode is disposed in the electrolytic cell as a cathode, and the electrolytic cell is provided with an inflow port into which the dilution water flows, and an overflow port at the upper end, which are located below the lower electrode. A device for treating contaminated soil, which is characterized in that 10. The polluted soil according to claim 6, wherein the aggregating device includes an ozone removing device that removes ozone in the dilution water that has passed through the electrolytic reduction device. Etc. processing equipment. 11. The apparatus for treating contaminated soil according to claim 10, wherein the ozone removing device includes activated carbon, and the activated carbon adsorbs ozone. 12. The method according to any one of claims 6 to 11,
A first container loaded on a first trailer and equipped with the heat treatment furnace and the diluting device, and loaded on a second trailer, the separation device, the ozone addition device, and the electrolytic reduction device. , A second container on which the aggregating device is mounted is provided, and a dilution water pipe and a treated water circulation system that connect the diluting device and the separating device to each other are provided between the first and second containers. A device for treating contaminated soil, which is characterized by being detachably arranged.