KR102263085B1 - Method for Removing of Heavy Metals and Oil from Contaminated Soils and Reusing the Washingwater - Google Patents

Abstract

Provided is a method for removing heavy metal and oil from complex contaminated soil and reusing washing water. The present invention has excellent separation and removal power of heavy metal and oil for contaminated soil in which the soil is complexly contaminated by highly concentrated heavy metal and oil, can increase the separation and removal efficiency of heavy metal and oil by using a magnetic separator, an oil-water separator and a peat moss filter, satisfies the standards of the soil environment conservation act by sequentially performing separation and removal of heavy metal contained in contaminated soil and oil contained in washing water, and can repeatedly recycle and reuse reused water from which heavy metal and oil have been efficiently separated and removed as washing water.

Description

Method for Removing of Heavy Metals and Oil from Contaminated Soils and Reusing the Washingwater

The present invention relates to a method of recycling wastewater generated while separating and removing heavy metals and oils contained in complex contaminated soil as washing water, and more particularly, to a method for recycling contaminated soil in which the soil is complexly contaminated by high concentrations of heavy metals and oil. It relates to a method of removing heavy metals and oils from complex contaminated soil and reusing wash water, which can satisfy the soil contamination concern standards due to its excellent removal ability, and increase process efficiency while recycling wastewater generated during the treatment of contaminated soil as washing water.

In general, soil contamination refers to a case in which harmful substances emitted by industrial activities are accumulated in the soil, and as a result, agricultural and livestock products harmful to human health are produced or the growth of crops is inhibited.

Such soil pollution is not only caused by soil dumping of industrial and household wastes and agricultural materials, but also mostly air or water pollution. The main causes of soil pollution include cadmium, zinc, copper, There are heavy metals such as lead, mercury, nickel, and chromium, light metals such as vanadium and beryllium, and non-metals such as arsenic and antimony, pesticides, fertilizers, and PCBs.

In recent years, pollution sources by oil such as oil leaking from oil storage facilities buried underground have become a problem, and heavy metal pollution sources include mines, smelters, factories using heavy metals, cement factories, and the like.

Among these, secondary pollution problems occur in the treatment of soil and wastewater contaminated by heavy metals. Therefore, it is necessary to study purification methods and introduce eco-friendly water treatment technology.

Accordingly, the separation and removal power of heavy metals on the contaminated soil, which is soil contaminated with heavy metals, is excellent, and the soil from which heavy metals are separated and removed through the process is beneficial for plant growth by purifying the wastewater generated when washing the contaminated soil for the separation and removal of heavy metals. It shows the effect, and wastewater is reused, and it is meaningful to develop an environment-friendly technology and a secondary environmental pollution problem.

On the other hand, methods for treating and restoring soil contaminated with soil include physicochemical methods such as soil washing, incineration, solidification, stabilization and solvent extraction, soil cultivation, composting, bioventing, and plant restoration. Biological methods and the like are known.

(Patent Document 1) KR10-0534067 B1

(Patent Document 2) KR10-1301218 B1

(Patent Document 3) KR10-2078534 B1

Patent Document 1 discloses, starting from the first dry sorting of the contaminated soil, wet sorting by high-pressure watering, the first washing, the second washing, and the dehydration process consisting of a purification process of contaminated soil; Restoration of contaminated soil including sludgeization and washing solution circulation process comprising the steps of collecting and first precipitating the contaminated washing solution generated in the wet sorting step and the first and second washing steps, then coagulating, secondary precipitation, neutralization, and re-supplying Disclosed are a method and apparatus for washing soil for the and screening treatment.

In Patent Document 2, a washing system that separates pollutants by washing soil contaminated with heavy metals or organic matter in several stages according to the size of particles, and soil contaminated only with organic matter introduced into the washing system or discharged from the washing system Disclosed is a soil decontamination system, comprising a thermal desorption system for thermally desorbing sludge to be used.

However, in the case of Patent Document 1 and Patent Document 2, the heavy metal remaining contained in the wastewater, which is the washing contaminated water generated while removing contaminants such as heavy metals contained in the contaminated soil as washing water, cannot be completely removed. When discharging wastewater containing heavy metals, water pollution is caused, and there are problems in that treatment costs are excessive.

In addition, in Patent Document 3, it is possible to increase the separation and removal efficiency of heavy metals remaining in wastewater generated during separation and removal of heavy metals by using water treatment facilities such as MF and RO, satisfy the soil environment conservation law standards, and include them in contaminated soil Although it has the advantage of being able to sequentially perform the separation and removal of heavy metals contained in wastewater and heavy metals contained in wastewater, the process of sedimenting wastewater, treating wastewater with chemicals, and treating chemically treated wastewater with water is complicated, increasing management and maintenance costs. and it was difficult to completely separate the oil contained in the wastewater.

Accordingly, the present invention is to solve the above-mentioned problems, and the purpose is to have excellent heavy metal removal ability for contaminated soil contaminated with heavy metals, and residual residuals included in wastewater generated during washing for separation and removal of heavy metals. By separating and removing heavy metals so that they can be reused as washing water for contaminated soil, they meet the soil environment conservation law standards, are eco-friendly, and remove heavy metals and oils from complex contaminated soils that can purify contaminated soil and increase the reuse efficiency of wastewater, and reuse washing water We want to provide a way

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. will be able

As a specific means for achieving the above object, a preferred embodiment of the present invention purifies the soil by washing the contaminated soil contaminated with oil and heavy metals as washing water, and treating the wastewater generated during the washing of the contaminated soil with water. In the method of reuse as washing water, the contaminated soil discharged from the hopper is supplied with washing water to the drum crusher and washed while primary crushing, and the contaminated soil first crushed in the drum crusher is supplied together with the washing water to the primary separator. A preliminary step of pretreatment with contaminated soil having a particle size of 35 mm or less; By supplying the contaminated soil having a particle size of 35 mm or less discharged from the primary sorter together with the washing water to the log washer, and supplying the secondly crushed and washed contaminated soil in the log washer along with the washing water to the first dewatering screen, a first particle size separation step of sorting and separating the washed contaminated soil into aggregates having a particle size of 35 mm or less to 2 mm or more; a secondary particle size separation step of separating the washed contaminated soil into purified soil having a particle size of less than 2 mm to 0.15 mm or more by supplying the contaminated soil discharged from the primary sorter together with washing water to the secondary sorter; a tertiary particle size separation step of sorting and separating the washed contaminated soil into fine soil having a particle size of less than 0.15 mm to 0.045 mm or more by supplying the contaminated soil discharged from the secondary sorter together with washing water to the tertiary sorter; By supplying and storing the washing water discharged from the tertiary separator to the reaction tank, each supplying a coagulant, a settling agent, and a neutralizing agent to the reaction tank and mixing them with the washing water, and supplying and storing the washing water treated with the chemical reaction in the reaction tank to the settling tank, A chemical treatment and precipitation step of coagulating and sedimenting ultra-fine particles having a particle size of less than 0.045 mm in the washing water of the settling tank, neutralizing the washing water in which ultra-fine particles are agglomerated and sedimenting, and precipitating the ultra-fine particles into sludge; a sludge treatment step of supplying the sludge deposited on the bottom surface of the settling tank to a filter press, forming a cake, and discharging to the outside; The washing water containing the oil suspended in the settling tank is supplied to the pressurization flotation tank to remove the floating substances generated during pressurization, and the washing water from which the floating substances are removed is supplied to the oil-water separator to separate the oil contained in the washing water to obtain the oil-separated washing water. Including; oil-water separation step of storing in a reused water tank to enable circulation and reuse;
The secondary particle size separation step is performed so that contaminated soil having a particle size of less than 2 mm continuously passing through the upper and lower mesh networks provided in the primary sorter does not pass through the mesh network of the secondary sorter. After being supplied to the screen tank side, pumping and supplying to the first hydro cyclone; Drop-supplying contaminated soil having a particle size of less than 2 mm to 0.15 mm or more, which is separated and discharged through the lower outlet of the first hydrocyclone, to the mesh network of the secondary sorter along with washing water; And supplying the contaminated soil having a particle size of less than 0.15mm separated and discharged through the upper outlet of the first hydrocyclone to the tertiary separator; including,
Between the first hydro cyclone and the secondary separator includes a wet magnetic separator through which the contaminated soil selectively discharged through the lower outlet of the first hydro cyclone passes along with the washing water, and in the wet magnetic separator containing heavy metals The contaminated soil from which the magnetic material is separated is supplied by falling into the mesh network of the secondary separator along with the washing water, and the magnetic material separated in the wet magnetic separator is supplied to the second dehydration screen together with the washing water to be dehydrated while being washed and then sorted by the mesh network. and discharged to the outside,
Between the first hydro cyclone and the tertiary separator includes a first buffer tank in which contaminated soil selectively discharged through the upper outlet of the first hydro cyclone is temporarily stored, and the first buffer tank is the tertiary separator. At the same time communicating with the screen tank of the second separator and the second dewatering screen, respectively, the contaminated soil having a particle size of less than 0.15 mm is washed with the washing water to prevent overload of the third separator and the second separator and the second separator. 2Optionally supplied to the dehydration screen,
In the tertiary particle size separation step, the polluted soil having a particle size of less than 0.15 mm discharged from the secondary sorter is supplied to the screen tank of the tertiary sorter so that it does not pass through the mesh network of the tertiary sorter, and then the second hydro pumping and supplying the cyclone; Drop-supplying contaminated soil having a particle size of less than 0.15 mm to 0.045 mm or more, which is separated and discharged through the lower outlet of the second hydro cyclone, to the mesh network of the tertiary separator along with washing water; And supplying the ultra-fine setto having a particle size of less than 0.045 mm separated and discharged through the upper outlet of the second hydro cyclone to the reactor; includes,
Between the second hydro cyclone and the reaction tank includes a second buffer tank for temporarily storing contaminated soil selectively discharged through the upper outlet of the second hydro cyclone, and the second buffer tank is connected to the reaction tank in communication At the same time, it is connected to the tertiary separator and selectively supplies contaminated soil having a particle size of 0.045 mm or less to the tertiary separator to prevent the load on the reactor,
The washing water discharged from the first dewatering screen is circulated to the inlet side of the drum crusher from which the reused water is pumped and supplied from the reused water tank together with the contaminated soil having a particle size of less than 2mm passing through the mesh network of the first dewatering screen. The washing water discharged from the second dewatering screen is circulated and supplied to the drum crusher to which the reused water is pumped from the reused water tank,
It provides a method for removing heavy metals and oil from complex contaminated soil and recycling washing water, characterized in that the reused water from which the heavy metals and oils are separated is circulated and supplied as washing water to the drum crusher and the first, second, and tertiary separators. do.

At this time, the first particle size separation step is a dry type provided on the exit side of the conveyor belt in the process of sorting and discharging the contaminated soil having a particle size of 35 mm or less to 2 mm or more selected by the first dewatering screen as an aggregate by a conveyor belt. It is possible to separate and remove the magnetic material contained in the aggregate by the magnetic separator.

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According to the preferred embodiment of the present invention as described above, there are the following effects.

Contaminated soil with a particle size of 35 mm or less containing heavy metals and oil is sequentially subjected to a primary particle size separation process, a secondary particle size separation process, and a tertiary particle size separation process. Aggregates having a particle size of 35 mm or less to 2 mm or more, less than 2 mm to It is possible to increase the restoration efficiency for contaminated soil by sorting and separating into purified soil having a particle size of 0.15 mm or more and fine soil having a particle size of less than 0.15 mm to 0.045 mm or more.

Magnetic materials such as iron pieces contained in aggregates having a particle size of 35 mm or less to 2 mm or more are separated and removed by a dry magnetic separator, and magnetic materials such as heavy metals used for washing water of purified soil having a particle size of less than 2 mm to 0.15 mm or more are separated by a wet magnetic separator. By separating and removing, it is possible to increase the quality of aggregates and fine soil that are separated and discharged after washing and sorting.

When washing contaminated soil, the washing water containing oil is sequentially passed through a pressurized flotation tank, an oil-water separator and a peat moss filter to increase the removal efficiency of the oil contained in the washing water to satisfy the Soil Environment Conservation Act standards. Since wastewater can be reused as washing water, it is possible to prevent water pollution and obtain environmentally friendly beneficial effects.

1 is a schematic diagram showing the overall configuration of applying the heavy metal and oil removal and washing water reuse method of complex contaminated soil according to an embodiment of the present invention.
Figure 2 is a process flow chart of applying the heavy metal and oil removal and washing water reuse method of complex contaminated soil according to an embodiment of the present invention.
3 is a schematic diagram illustrating a preliminary process, 1,2, and tertiary particle size separation processes in the heavy metal and oil removal and washing water reuse method of complex contaminated soil according to an embodiment of the present invention.
Figure 4 is a schematic diagram showing a chemical treatment, precipitation process, oil-water separation process in the heavy metal and oil removal and washing water reuse method of complex contaminated soil according to an embodiment of the present invention.
5 is a schematic view showing a sludge treatment process in the heavy metal and oil removal and washing water reuse method of complex contaminated soil according to an embodiment of the present invention.
6 is a schematic view showing an oil-water separator applied to a heavy metal and oil removal and washing water reuse method of complex contaminated soil according to an embodiment of the present invention.
7 is a schematic view showing a peat moss filter unit applied to the heavy metal and oil removal and washing water reuse method of complex contaminated soil according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment in which a person of ordinary skill in the art to which the present invention pertains can easily practice the present invention will be described in detail. However, in the detailed description of the structural principle of a preferred embodiment of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, the same reference numerals are used throughout the drawings for parts having similar functions and functions.

In addition, throughout the specification, when a part is 'connected' with another part, it is not only 'directly connected' but also 'indirectly connected' with another element interposed therebetween. include In addition, 'including' a certain component does not exclude other components unless otherwise stated, but means that other components may be further included.

As shown in FIGS. 1 to 5, the heavy metal and oil removal and washing water reuse method of the complex contaminated soil according to a preferred embodiment of the present invention washes the contaminated soil containing heavy metals and oil in the soil as washing water to separate the heavy metals Preliminary step (S1), 1st particle size separation step (S2), 2nd particle size separation so that the reused water from which the removed aggregate, purified soil and fine soil are discharged and separated and removed can be recycled and reused as washing water It includes a step (S3), a tertiary particle size separation step (S4), a chemical treatment and settling step (S5), a sludge treatment step (S6)), and an oil-water separation step (S7).

In the preliminary step (S1), as shown in FIGS. 1, 2 and 3, the polluted soil having a particle size of 35 m or less discharged from the hopper 111 is washed and pre-treated to obtain a particle size of 35 mm or less. It is a preliminary treatment by washing the contaminated soil with the first crushing so that it can be supplied to the post-process.

That is, the contaminated soil, the object to be treated, stored in a certain amount in the hopper 111 is discharged from the outlet, and the contaminated soil having a particle size of about 35 mm or less is supplied with washing water into the drum crusher 112 through the conveyor belt 117. , the contaminated soil supplied to the inside of the drum crusher 112 is washed with washing water to separate and remove heavy metals and oils, and is subjected to primary crushing treatment into contaminated soil having a smaller particle size.

At this time, it is preferable that only the contaminated soil pulverized to have a particle size of 35 mm or less by the pretreatment process is put into the hopper 111 and stored, and the drum crusher 112 contains the contaminated soil having a particle size of 35 mm or less. It is necessary to increase the moisture content by supplying a large amount of washing water so that it is washed while pulverizing to have a small particle size and at the same time, the particle size selection for the contaminated soil in the post-process, the primary sorter, can be smoothly performed.

The contaminated soil washed while being primary crushed in the drum crusher 112 is discharged from the exit side of the drum crusher and has an upper mesh network 113a of approximately 12 mm and a lower mesh network 113b of approximately 2 mm in a primary separator ( 113) by supplying with washing water, contaminated soil having a particle size of 12 mm or more caught on the upper mesh network 113a, and contamination having a particle size of 2 mm or more that passes through the upper mesh network and is caught on the lower mesh network 113b The soil is supplied to the log washer 114, which will be described later, to perform a secondary crushing and washing process.

In addition, the contaminated soil having a particle size of less than 2 mm that passes through the lower mesh network 113b of the primary sorter is washed with the washing water discharged from the screen tank of the primary sorter 113 and washed to the secondary sorter 121 side to be described later. supplied with

The first particle size separation step (S2) is, as shown in Figs. 1, 2 and 3, the contaminated soil having a particle size of 2 mm or more discharged from the primary sorter 113 at the entrance of the log washer 114. By supplying it together with washing water, it washes the contaminated soil with a particle size of 2mm or more while secondly pulverizing it.

By supplying the secondly pulverized contaminated soil discharged from the exit side of the log washer 114 to the first dewatering screen 115 having an approximately 2mm mesh network 115a together with the washing water, heavy metals and oil are separated by the washing water. It is the primary separation by selecting the washed contaminated soil into aggregates having a particle size of 35 mm or less to 2 mm or more.

That is, the contaminated soil supplied to the first dewatering screen 115 is washed by washing water and at the same time, the contaminated soil having a particle size of 35 mm or less to 2 mm or more is selected as aggregate by the mesh network 115a to which vibration is given and separated and , the separated and sorted aggregates are placed in the yard through the conveyor belt 118 .

In the process of sorting and discharging contaminated soil having a particle size of 35 mm or less to 2 mm or more to the yard by the conveyor belt 118 as an aggregate, which is selected and dehydrated by the first dewatering screen 115, the conveyor belt 118 It is preferable to separate and remove magnetic materials, which are waste metals, such as scraps or metal fragments, included in the aggregate by the dry magnetic separator 116 provided on the exit side for discharging treatment.

And, the contaminated soil having a particle size of less than 2mm passing through the mesh network 115a of the first dewatering screen 115 is 35mm or less contaminated soil with the washing water discharged from the screen tank of the first dewatering screen 115. It is circulated and supplied to the inlet side of the drum crusher 112 for primary crushing and washing.

Here, the washing water discharged from the first dewatering screen 115 is a drum crusher that requires a large amount of washing water in the process of primary pulverizing and washing contaminated soil of 35 mm or less as well as contaminated soil having a particle size of less than 2 mm ( 112) by the pump member, it is possible to reduce the amount of washing water that is treated and reused as a whole, so that the overall process efficiency can be increased.

The secondary particle size separation step (S3), as shown in FIGS. 1, 2 and 3, is less than 2 mm continuously passing through the upper and lower mesh networks 113a and 113b of the primary sorter 113. By supplying the contaminated soil having a particle size to the secondary separator 121 together with the washing water discharged from the primary separator 113, the washed contaminated soil to be separated from heavy metals and oil by the washing water has a particle size of less than 2 mm to 0.15 mm or more. Separation with purified soil.

That is, the contaminated soil supplied to the secondary sorter 121 is washed by washing water and at the same time, the contaminated soil having a particle size of less than 2 mm to 0.15 mm or more is separated into purified soil by the mesh network 121a to which vibration is given. , the separated and sorted purified soil is stored in the yard through the conveyor belt 122 .

Contaminated soil having a particle size of less than 2 mm that is selected by successively passing through the upper and lower mesh networks 113a and 113b provided in the primary sorter 113 is directly supplied to the mesh network 121a of the secondary sorter. It is supplied to the screen tank of the secondary sorter 121 along with the washing water, and then pumped and supplied to the first hydrocyclone 123 .

That is, the first hydro cyclone 123 has a structure in which the diameter of the lower outlet can be adjusted so that the particle size of the contaminated soil can be selectively separated, and the contaminated soil particles supplied by turning the contaminated soil supplied together with the washing water at a high speed It is to efficiently separate up and down based on the specific gravity and particle size of

The polluted soil discharged through the lower outlet of the first hydro cyclone 123 is sorted into purified soil having a particle size of less than 2 mm to 0.15 mm or more in the mesh network 121a of the secondary separator 121. The secondary separator ( 121), the contaminated soil having a particle size of less than 0.15 mm discharged through the upper outlet of the first hydrocyclone 123 due to its relatively light specific gravity and small particle size than the purified soil is a tertiary separator ( 131) is supplied.

Contaminated soil having a particle size of less than 2 mm to 0.15 mm or more discharged from the lower outlet of the first hydro cyclone 123 is supplied to the wet magnetic separator 124 together with the washing water to separate the magnetic material which is a heavy metal contained in the washing water, and the Contaminated soil from which heavy metals are separated is supplied by falling to the mesh network 121a of the secondary separator 121 together with washing water, and the magnetic material, which is a heavy metal separated from the wet magnetic separator 124, is supplied with washing water along with a second dehydration screen 125. ) is supplied to, and then dehydrated while being washed, and then selected by the mesh network 125a and discharged to the outside.

At this time, the contaminated soil having a particle size of less than 2 mm discharged from the screen tank of the primary sorter 113 along with the washing water is not directly supplied to the mesh network 121a of the secondary sorter 121, but rather of the secondary sorter. After being temporarily stored in the screen tank, the first hydrocyclone 123 is pumped and supplied to the mesh network of the secondary sorter via this, thereby preventing overload and damage to the secondary sorter 121 and increasing the classification efficiency.

The washing water discharged from the screen tank of the second dewatering screen 125 is a drum crusher 112 that requires a large amount of washing water in the process of first crushing and washing contaminated soil of 35 mm or less by means of a pump member. By circulating supply, it is possible to reduce the amount of washing water that is treated and reused, so that overall process efficiency can be increased.

And, between the first hydro cyclone 123 and the tertiary separator 131, a first buffer tank 126, such as a dirty tank, in which contaminated soil discharged through the upper outlet of the first hydro cyclone is temporarily stored. Including, the first buffer tank may be connected to the screen tank of the tertiary separator 131 to supply contaminated soil having a particle size of less than 0.15 mm together with the washing water.

At the same time, the first buffer tank 126 is connected to the screen tank of the secondary separator 121 and the screen tank of the second dewatering screen 125, respectively, to remove contaminated soil having a particle size of less than 0.15 mm. An overload of the tertiary separator can be prevented by re-supplying the secondary separator or selectively supplying each to the second dewatering screen.

At this time, the contaminated soil having a particle size of less than 0.15 mm discharged at high speed from the upper outlet of the first hydro cyclone 123 is the upper outlet of the first hydro cyclone 123 and the screen tank of the tertiary separator 131 and It is temporarily stored together with the washing water in the first buffer tank 126 provided between the and then supplied at atmospheric pressure to the screen tank of the tertiary separator 131, thereby increasing the internal pressure of the screen tank of the tertiary separator 131 to increase the tertiary It is possible to prevent deterioration of the efficiency of classifying contaminated soil in the mesh network of the sorter 131 .

The tertiary particle size separation step (S4) is, as shown in FIGS. 1, 2 and 3, the contaminated soil having a particle size of less than 0.15 mm discharged from the secondary sorter 121 with the tertiary sorter 131. By supplying it together with washing water, the washed contaminated soil is separated into fine soil having a particle size of less than 0.15 mm to 0.045 mm or more so that heavy metals and oil are separated by the washing water.

That is, the contaminated soil supplied to the tertiary separator 131 is washed by washing water and at the same time, the contaminated soil having a particle size of less than 0.15 mm to 0.045 mm or more is separated into fine soil by the mesh network 131a to which vibration is given. Then, the fine soil to be separated and sorted is placed in the yard through the conveyor belt 132 .

Contaminated soil having a particle size of less than 0.15 mm discharged from the screen tank of the secondary sorter 121 does not pass through the mesh network 131a of the tertiary sorter and is supplied to the secondary sorter 131 along with the washing water. It is then pumped and supplied to the second hydro cyclone 134 .

The second hydro cyclone 134, like the first hydro cyclone 123, has a structure capable of adjusting the diameter of the lower outlet so as to selectively separate the particle size of the contaminated soil, so that the contaminated soil supplied together with the washing water is discharged at a high speed. It is to efficiently separate up and down according to the specific gravity and particle size of polluted soil particles through rotation.

The tertiary sorter so that the contaminated soil discharged through the lower outlet of the second hydrocyclone 133 is sorted into fine soil having a particle size of less than 0.15 mm to 0.045 mm or more in the mesh network 131a of the tertiary separator 131. Contaminated soil having a particle size of less than 0.045 mm, which is supplied by falling through the mesh network of 131, and is discharged with washing water through the upper outlet of the second hydro cyclone 133 due to its relatively light specific gravity and smaller particle size than the fine soil, is It is supplied to the reaction tank 210 for precipitating the foreign substances contained in the washing water.

At this time, the contaminated soil having a particle size of less than 0.15 mm discharged from the screen tank of the secondary sorter 121 together with the washing water is not directly supplied to the mesh network 131a of the tertiary sorter 131, but is not supplied by the tertiary sorter. After being temporarily stored in the screen tank of the second hydro cyclone 134 is pumped and supplied to the mesh network of the tertiary sorter 131 via this drop supply, thereby preventing overload and damage to the tertiary separator 121 while improving the classification efficiency. can be raised

And, between the second hydro cyclone 133 and the reaction tank 210, a second buffer tank 136 such as a dirty tank in which the contaminated soil discharged through the upper outlet of the second hydro cyclone 134 is temporarily stored. may include, and the contaminated soil having a particle size of less than 0.045 mm temporarily stored in the second buffer tank 136 may be supplied together with the washing water to the reaction tank 210 or may be circulated to the tertiary separator 131. have.

The second buffer tank 136 is connected to the reaction tank 210 so as to supply ultrafine soil, which is contaminated soil having a particle size of less than 0.045 mm, to the reaction tank 210, and at the same time is connected to the screen tank of the tertiary separator to connect the reactor and the third separator. It is possible to prevent overload of the reactor by selectively supplying ultra-fine setto and washing water having a particle size of less than 0.045 mm to

At this time, the contaminated soil having a particle size of less than 0.045 mm discharged at high speed from the upper outlet of the second hydro cyclone 134 is provided between the upper outlet of the second hydro cyclone 134 and the reaction tank 210. The second buffer tank 136 is temporarily stored together with the washing water and then supplied to the reaction tank at atmospheric pressure, thereby increasing the internal pressure of the reaction tank to prevent deterioration of the reaction efficiency in the reaction tank.

In the chemical treatment and precipitation step (S5), as shown in FIGS. 1, 2, and 4, the washing water discharged from the tertiary separator 131 is supplied to the reaction tank 210 and stored, and is less than 0.045 mm. A coagulant, a settling agent, and a neutralizing agent are respectively supplied to the reaction tank 210 in which the wash water containing the contaminated soil having a particle size is mixed, and a predetermined amount is mixed with the washing water, and the washing water treated with the chemical reaction in the reaction tank 210 is added to the settling tank 220. By supplying and temporarily storing the sedimentation tank 220, ultra-fine soil, which is contaminated soil having a particle size of less than 0.045 mm, contained in the washing water is aggregated and sedimented, and the ultra-fine soil is neutralized in the washing water in which the ultra-fine set soil is aggregated and settled, and the ultra-fine soil is converted into sludge. precipitation treatment with

That is, the washing water pumped out by the pump member from the lower side of the tertiary separator and discharged through the upper outlet of the second hydro cyclone is in the reaction tank 210 with ultra-fine soil, which is contaminated soil having a particle size of less than 0.045 mm. supplied and stored in a certain amount.

The reaction tank 210 is individually supplied with a predetermined amount of the coagulant of the first chemical tank 231, the settling agent of the second chemical tank 232, and the neutralizing agent of the third chemical tank 233 to react with the washing water filled in the reaction tank. By doing so, the ultra-fine setto contained in the washing water is aggregated by the coagulant, and the aggregated ultra-fine sediment is precipitated by the precipitating agent, while the washing water in which the ultra-fine setto is chemically treated by the coagulant and the settling agent is neutralized with a neutralizing agent. will be.

The first chemical tank 231 is a tank member for storing chemical water in which a coagulant such as alum is mixed with a predetermined amount of water and a predetermined ratio, and the second chemical tank 232 is settling such as FLOC. I am a tank member for storing a certain amount of water and other chemical water mixed in a certain ratio, and the third chemical tank 233 is a tank in which a neutralizing agent such as caustic soda (sodium hydroxide: NaOH) is mixed with a certain amount of water in a certain ratio. It is a tank member in which other chemical water is stored.

The chemical water stored in the first, second, and third chemical tanks 231,232,233 is pumped and supplied to the reaction tank 210 by a pump member, so that it is mixed with the washing water stored in the reaction tank and agglomerates the ultra-fine setto contained in the washing water, It is reacted to neutralize the washing water while sedimenting the agglomerated ultrafine grains.

At this time, it is preferable that the first, second and third chemical tanks 231,232 and 233 are provided with agitating blades rotated by a driving source so that chemicals such as coagulant, settling agent, and neutralizing agent and water can be smoothly mixed with each other, It is preferable to provide a water level sensor, respectively, so as to replenish the chemical water in real time while measuring the level of the chemical water filled in the first, second and third chemical tanks in real time.

The reaction tank 210 includes a first reaction tank in which the chemical water pumped from the first chemical tank 231 in which a predetermined amount of water and chemical water mixed with a coagulant is stored in a predetermined ratio and washing water, which is wastewater, react, and a predetermined amount of water and Another chemical water pumped from the second chemical tank 232 in which other chemical water mixed with a settling agent is stored in a predetermined ratio and a second reaction tank in which a predetermined amount of water and a neutralizing agent are mixed in a predetermined ratio are reacted with other chemical water pumped and supplied It may consist of a third reaction tank in which another chemical water pumped and supplied from the third chemical tank 233 in which the chemical water is stored and the washing water, which is wastewater, react.

The first, second, and third reaction tanks may be independently provided so as to be adjacent to each other inside one reaction tank each divided by a separation partition wall, and another reaction tank adjacent to the upper end of the separation partition wall separating the reaction tanks from each other It may be provided with a weir that overflows only the supernatant of the chemically treated wastewater.

Preferably, the first, second and third reaction tanks constituting the reaction tank are provided with agitating blades rotated by a driving source so as to promote a chemical reaction between the washing water, which is wastewater, and chemicals, and chemicals are used with a coagulant, a settling agent and a neutralizing agent. It is preferable to have a pH meter each so as to measure and confirm the pH of the washing water to be treated in real time, and to control the amount of chemical input based on the confirmed measured value.

In addition, the chemically treated washing water in the reaction tank 210 is supplied to the settling tank 220, so that the ultra-fine setto contained in the chemically treated washing water aggregates and settles into sludge, and then is supplied to the filter press 260 to be described later. The washing water neutralized in the settling tank is supplied to the pressure flotation tank 320 and the oil-water separator 340 to be described later to perform an oil-water separation process of separating the washing water and oil to be reused.

In the sludge treatment step (S6), as shown in FIGS. 1, 2 and 5 , the sludge deposited on the bottom surface of the settling tank 220 is supplied to the filter press 260 and caked and discharged to the outside. will do

That is, the sludge deposited on the bottom surface of the settling tank 220 is pumped and supplied to a stirring tank 240 having stirring blades rotated by a motor member, stored first, and stirred for a certain period of time, and then the adjacent silo 250 ) and waits for a certain amount of time.

The sludge temporarily stored in the silo 250 is supplied to the inlet side of the filter press 260 and then compressed by the pressure of the pressure tank to form a sludge cake and discharged to the outside. A filter that is compressed water generated when the sludge is compressed. Press water is discharged from the filter press 260 to the outside and temporarily stored in the compressed water tank 280, and the filter press water temporarily stored in the compressed water tank is pumped by a pump member to be circulated and supplied to the settling tank 220. can

At this time, the supernatant water of the settling tank 220 is supplied to the process tank 310 side so that an oil-water separation process of separating washing water and oil from each other can be performed.

In the oil-water separation step (S7), as shown in FIGS. 1, 2 and 4, the washing water, which is the supernatant water containing the oil suspended in the settling tank 220, is supplied to the pressurized flotation tank 320 to remove the suspended matter 1 By supplying the washing water from which the tea is removed and the suspended matter is removed to the oil-water separator 340 to secondarily separate the oil contained in the washing water, the washing water from which the oil is separated can be circulated and used as the reused water. Stored in the reused water tank 360. will do

The washing water, which is the supernatant water, along with the oil floating on the surface of the settling tank 220, is temporarily stored in the process tank 310, and the washing water temporarily stored in the process tank is supplied to the pressurization flotation tank 320 by a pump member, so that the pressure tank 330 ), when pressure is applied to the washing water supplied to the pressurized flotation tank, the fine foreign substances contained in the washing water are attached to the fine bubbles generated when the air is dissolved in the washing water and left at atmospheric pressure, and it floats as a float, The suspended solids are separated and removed.

Then, the washing water from which the suspended matter is removed is supplied to the oil-water separator 340 to perform a process of separating oil such as waste oil included in the washing water.

As shown in FIG. 6, the washing water discharged from the pressurizing flotation tank 320 is supplied to and filled in the sludge treatment tank 341, and then overflows the partition wall dividing the sludge treatment tank and the oil-water separation tank 342 into the oil-water separation tank. Oil is suspended by the provided oil flotation separation pack, and the washing water from which the oil is separated sinks down and is discharged to the adjacent wear 345 side.

The oil caught by the oil flotation separation pack is separated and removed only by circulating the oil collection cloth which is provided on one side of the oil-water separation tank and is immersed by the motor member of the skimmer.

The washing water moving toward the wear 345 overflows the partition wall dividing the wear and the micro oil adsorption tank 346 and is supplied to the inside of the micro oil adsorption tank, and a porous distribution plate provided on the uppermost layer of the micro oil adsorption tank ( 137), the washing water uniformly discharged downward in the self-weight direction adsorbs the fine oil by the oil adsorbent 138, which is a fiber aggregate made of lipophilic polypropylene, to remove it secondarily, and then is discharged to the outside.

In addition, the washing water from which the oil containing the micro-oil is removed in the oil-water separator 340 is filled and stored in the reused water tank 360 so that it can be recycled and reused as the reused water, and the reused water stored in the reused tank is the drum crusher. 112, the log washer 114, the first, second and tertiary sorters 113, 121, 131, and the first and second dewatering screens 115, 125 can be pumped and supplied to be used as washing water for washing contaminated soil. have.

Here, the reused water tank 360 is communicated with a fresh water tank 370 in which a predetermined amount of fresh water is filled and stored, and the fresh water tank and the reused water tank are communicated with the make-up water tank 380, so that the reused water tank ( 360) is detected as a preset low water level, or when the water level of the reuse water tank and the fresh water tank is detected as a preset low water level, the make-up water filled in the make-up water tank is supplied to the reuse water tank and the fresh water tank, respectively. can do.

In addition, as shown in FIGS. 4 and 7 , between the oil-water separator 340 and the reused water tank 360, the reused water, which is the washing water from which the oil has been separated and removed in the oil-water separator 340 while communicating with each other, is provided. At least one peat moss filter unit 400 may be included in the connection line supplied to the reused water tank 360 .

The peat moss filter unit 400 includes a filter housing 410 , a porous supply pipe 420 , and a peat moss 430 , and the filter housing 410 has an interior in which the peat moss 430 can remove contaminants from the washing water. A space is provided, and a peat moss 430 is provided inside the filter housing 410 .

Accordingly, the washing water transferred from the oil-water separator 340 to the reused water tank is supplied to the inside of the filter housing 410 through the porous supply pipe 420 , purified by the peat moss 430 , and then the filter housing 410 . ) is transferred to and stored in the reused water tank 360 while being discharged through an outlet formed in the lower portion, so that the washing water discharged from the oil-water separator is restored to the best water quality and can be recycled and reused.

The present invention described above is not limited by the above-described embodiments and the accompanying drawings, and it is common in the technical field to which the present invention pertains that various substitutions, modifications and changes are possible without departing from the technical spirit of the present invention. It will be clear to those who have the knowledge of

111 : Hopper
112: drum crusher
113: primary sorter
114: log washer
115: first dehydration screen
116: dry magnetic separator
125: second dehydration screen
121: secondary sorter
123: first hydrocyclone
124: wet magnetic separator
131: tertiary sorter
210: reaction tank
220: settling tank
231,232,233: 1st, 2nd and 3rd chemical tanks
260: filter press
310: process tank
320: pressurized flotation tank
340: oil-water separator
400: peat moss filter unit

Claims (8)

In the method of washing contaminated soil contaminated with oil and heavy metals as washing water to purify the soil, and treating wastewater generated during washing of the contaminated soil to water and reuse it as the washing water,
Contaminated soil discharged from the hopper is supplied with washing water to the drum crusher and washed while primary crushing, and the contaminated soil first crushed in the drum crusher is supplied together with washing water to the primary separator. Contaminated soil having a particle size of 35 mm or less a preliminary step of pre-processing with
By supplying the contaminated soil having a particle size of 35 mm or less discharged from the primary sorter together with the washing water to the log washer, and supplying the secondly crushed and washed contaminated soil in the log washer along with the washing water to the first dewatering screen, a first particle size separation step of sorting and separating the washed contaminated soil into aggregates having a particle size of 35 mm or less to 2 mm or more;
a secondary particle size separation step of separating the washed contaminated soil into purified soil having a particle size of less than 2 mm to 0.15 mm or more by supplying the contaminated soil discharged from the primary sorter together with washing water to the secondary sorter;
a tertiary particle size separation step of sorting and separating the washed contaminated soil into fine soil having a particle size of less than 0.15 mm to 0.045 mm or more by supplying the contaminated soil discharged from the secondary sorter together with washing water to the tertiary sorter;
By supplying and storing the washing water discharged from the tertiary separator to the reaction tank, each supplying a coagulant, a settling agent, and a neutralizing agent to the reaction tank and mixing them with the washing water, and supplying and storing the washing water treated with the chemical reaction in the reaction tank to the settling tank, A chemical treatment and precipitation step of coagulating and sedimenting ultra-fine particles having a particle size of less than 0.045 mm in the washing water of the settling tank, neutralizing the washing water in which ultra-fine particles are agglomerated and sedimenting, and precipitating the ultra-fine particles into sludge;
a sludge treatment step of supplying the sludge deposited on the bottom surface of the settling tank to a filter press, forming a cake, and discharging to the outside;
The washing water containing the oil suspended in the settling tank is supplied to the pressurization flotation tank to remove the floating substances generated during pressurization, and the washing water from which the floating substances are removed is supplied to the oil-water separator to separate the oil contained in the washing water to obtain the oil-separated washing water. Including; oil-water separation step of storing in a reused water tank to enable circulation and reuse;
The second particle size separation step is,
Contaminated soil having a particle size of less than 2 mm that continuously passes through the upper and lower mesh networks provided in the primary sorter is supplied to the screen tank side of the secondary sorter so that it does not pass through the mesh network of the secondary sorter. pumping and supplying the hydrocyclone;
Drop-supplying contaminated soil having a particle size of less than 2 mm to 0.15 mm or more, which is separated and discharged through the lower outlet of the first hydrocyclone, to the mesh network of the secondary sorter along with washing water; and
supplying the contaminated soil having a particle size of less than 0.15 mm separated and discharged through the upper outlet of the first hydro cyclone to the tertiary separator; including,
Between the first hydro cyclone and the secondary separator includes a wet magnetic separator through which the contaminated soil selectively discharged through the lower outlet of the first hydro cyclone passes along with the washing water,
In the wet magnetic separator, the contaminated soil from which the magnetic material containing the heavy metal is separated is supplied to the mesh network of the secondary separator along with the washing water, and the magnetic material separated in the wet magnetic separator is supplied to the second dehydration screen together with the washing water for washing. After being dehydrated, it is sorted by a mesh network and discharged to the outside.
Between the first hydro cyclone and the tertiary selector includes a first buffer tank in which the contaminated soil selectively discharged through the upper outlet of the first hydro cyclone is temporarily stored,
The first buffer tank is communicated with the screen tank of the tertiary separator and at the same time is connected to the secondary separator and the second dewatering screen, respectively, to prevent overload of the tertiary separator. Contaminated soil having a particle size of less than 0.15 mm is selectively supplied to the second separator and the second dehydration screen along with the washing water,
The third particle size separation step is,
supplying the polluted soil having a particle size of less than 0.15 mm discharged from the secondary sorter to the screen tank of the tertiary sorter so that it does not pass through the mesh network of the tertiary sorter, and then pumping and supplying it to a second hydrocyclone;
Drop-supplying contaminated soil having a particle size of less than 0.15 mm to 0.045 mm or more, which is separated and discharged through the lower outlet of the second hydro cyclone, to the mesh network of the tertiary separator along with washing water; and
supplying the ultra-fine setto having a particle size of less than 0.045 mm that is separated and discharged through the upper outlet of the second hydro cyclone to the reactor; includes,
Between the second hydro cyclone and the reaction tank includes a second buffer tank in which the contaminated soil selectively discharged through the upper outlet of the second hydro cyclone is temporarily stored,
The second buffer tank is connected to the reactor and at the same time to the tertiary separator to selectively supply contaminated soil having a particle size of 0.045 mm or less to the tertiary separator to prevent a load on the reactor,
The washing water discharged from the first dewatering screen is circulated to the inlet side of the drum crusher from which reused water is pumped and supplied from the reused water tank together with the contaminated soil having a particle size of less than 2mm passing through the mesh network of the first dewatering screen.
The washing water discharged from the second dewatering screen is circulated and supplied to the drum crusher to which the reused water is pumped and supplied from the reused water tank,
The heavy metal and oil removal and washing water reuse method of complex contaminated soil, characterized in that the reused water from which the heavy metals and oils are separated is recycled and supplied as washing water to the drum crusher and the primary, secondary and tertiary separators. According to claim 1,
The first particle size separation step,
The magnetic material contained in the aggregate by the dry magnetic separator provided on the exit side of the conveyor belt in the process of sorting and discharging contaminated soil having a particle size of 35 mm or less to 2 mm or more selected by the first dehydration screen by a conveyor belt as an aggregate. A method of removing heavy metals and oil from complex contaminated soil and reuse of washing water, characterized in that it separates and removes.

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