KR102423206B1 - System for treating mining drainage using volume changeable agitator tank - Google Patents

Abstract

The present invention relates to a mine drainage treatment system.
In the photo-acid drainage treatment system according to the present invention, a coagulant is added to agglomerate the contaminants in the photo-acid drainage into flocs and then precipitate. In the present invention, the use of a slow stirring tank having a unique structure is characterized in that it is possible to keep the coagulant and the mineral acid drainage agitation time constant at all times even under the condition that the flow rate is not constant and varies widely.

Description

Mine drainage treatment system using variable agitation tank {SYSTEM FOR TREATING MINING DRAINAGE USING VOLUME CHANGEABLE AGITATOR TANK}

The present invention relates to a technology for reducing environmental pollution, and more particularly, to a mine drainage treatment system for environmentally friendly treatment of mine drainage discharged from a mine.

Environmental problems caused by abandoned mines and abandoned mines include ground subsidence, heavy metal contamination of rivers and soils due to loss of waste-rock and tailings (mineral residue), and water pollution by shaft runoff and waste-rock leachate. In particular, water pollution by so-called acid mine drainage from underground coal mine waste-rock heaps has been recognized as a fairly serious problem since the mid-1990s.

Acid mine drainage is formed when sulfide minerals such as pyrite (FeS ₂ ) and pyrite (FeS) exposed to the atmosphere react with oxygen and water and are oxidized. is characterized.

Although such acid mine drainage is a pollutant in itself, it elutes and moves heavy metals around it due to its low pH, thereby polluting the surrounding surface water and groundwater, thereby destroying the aquatic ecosystem. In addition, metal ions in the mine drainage are oxidized and precipitated as metal hydroxides such as Fe(OH) ₃ , which causes red-brown or white deposits at the bottom of the river (yellow boy phenomenon), impairing the aesthetics.

The purification method of such acid mine drainage is largely divided into an active treatment method and a passive treatment method. The active treatment method uses pH control using a neutralizing agent, ion exchange, adsorption, coagulation, filtration, and the like. Representative active treatment methods include reverse osmosis, ion exchange, and electrodialysis. However, although this active treatment method has excellent treatment efficiency, there is a problem that the maintenance cost is high because equipment, chemicals, manpower, and power must be continuously input. Natural remedies are widely used.

Meanwhile, recently, the so-called “semi-active” method is widely used as an intermediate step between the passive treatment method and the active treatment method. In the semi-active method, slaked lime is injected as a neutralizing agent without using electric energy to reduce mine drainage. Neutralize and precipitate the metal hydroxide in the form of sludge.

In a semi-active treatment system, a plurality of tanks are generally arranged in a line according to a process sequence, for example, a pH control tank, a stirring tank, and a settling tank are arranged in the order. The stirring tank may be operated separately as a rapid stirring tank and a slow stirring tank.

Many of these chemical treatment systems are basically designed based on a wastewater treatment system, but various problems occur because the objects of the sewage treatment system and the mine drainage treatment system are different.

Flow and processing capacity are issues.

The wastewater treatment system is mainly used in factories, and the amount of wastewater generated daily according to the process conditions is predictable and is maintained constant. However, the amount of mine drainage varies greatly depending on the season and precipitation conditions. Since the flow rate of treated water varies greatly, the design of the system becomes difficult, and if the system is designed with the maximum capacity, there is a problem that the mine drainage cannot be efficiently treated. In particular, in the stirring tank, a coagulant is injected and mixed with the photo-acid drainage. If the coagulation tank is designed to be large in case there is a lot of precipitation, if the time for the photo-acid drainage in the agglomeration tank is too long, the flocculation effect is rather reduced. have.

An object of the present invention is to solve the above problems, and it is an object of the present invention to provide a mine drainage treatment system with an improved structure so that the mine drainage can be stably treated even when the flow rate of the mine drainage is greatly changed.

On the other hand, other objects not specified in the present invention will be additionally considered within the range that can be easily inferred from the following detailed description and effects thereof.

A photo-acid drainage treatment system according to an embodiment of the present invention for achieving the above object includes: a pH adjusting tank for adjusting the pH of the acid mine drainage; a stirring tank disposed at the rear end of the pH adjusting tank to add a coagulant to the photo-acid drainage for stirring, and a stirring tank capable of controlling the time that the photo-acid drainage meets the coagulant and is stirred; and a sedimentation tank disposed at the rear end of the stirring tank to precipitate sludge from the mine drainage.

According to the present invention, it is preferable that the stirring tank is separated into a rapid stirring tank and a slow stirring tank according to the process sequence.

In particular, it is preferable that the acid drainage and the coagulant in the slow stirring tank be discharged into the settling tank after being stirred with each other for 15 to 20 minutes.

To this end, the stirring tank is disposed elongated in one direction, the main body having an inlet and an outlet formed on one side and the other side, respectively, so that the mine drainage is in and out, and between the inlet and the outlet so that the mine drainage forms a zigzag path. It includes a partition extending from the front and rear surfaces of the main body, a stirrer respectively installed in the space divided by the partition, and a coagulant injector installed in the divided space, respectively.

In another embodiment of the present invention, the agitation tank includes a first tank portion having an inlet portion and an outlet portion respectively formed on one side and the other side to enable the inflow and outflow of the mine drainage, and is installed inside the first tank portion to provide the first A second tank unit comprising: a second tank unit capable of elevating within the tank unit; and a flange unit extending from an upper periphery of the second tank unit to an inner peripheral surface of the first tank unit and capable of moving up and down together with the second tank unit; As it descends and descends, the volume in which the mine drainage is accommodated increases and decreases.

In the present invention, a flow sensor for measuring the flow rate of the photo-acid drainage, and a controller that receives a signal from the flow sensor and adjusts at least one of an injection amount and an injection position of the coagulant to adjust the time during which the photo-acid drainage and the coagulant are stirred provide more

In the present invention, even when the flow rate of the photo-acid drainage changes very significantly, it is possible to maintain a constant time during which the coagulant and the photo-acid drainage are stirred with each other in the slow stirring tank. There is an advantage in that by forming a floe with a sufficient size, contaminants can be easily precipitated and removed.

On the other hand, even if it is an effect not explicitly mentioned herein, it is added that the effects described in the following specification expected by the technical features of the present invention and their potential effects are treated as described in the specification of the present invention.

1 is a schematic diagram of a mine drainage treatment system according to an example of the present invention.
Figure 2 is a schematic perspective view of the slow stirring tank shown in Figure 1;
3 is a schematic plan view of the slow stirring tank of FIG.
4 is a schematic longitudinal cross-sectional view of a slow stirring tank employed in another example of the present invention.
5 is a view for explaining the operation of the slow stirring tank shown in FIG.
※ It is revealed that the accompanying drawings are exemplified as a reference for understanding the technical idea of the present invention, and the scope of the present invention is not limited thereby.

In the description of the present invention, if it is determined that the subject matter of the present invention may be unnecessarily obscured as it is obvious to those skilled in the art with respect to related known functions, the detailed description will be omitted.

Hereinafter, with reference to the accompanying drawings, an embodiment of the present invention will be described in more detail.

1 is a schematic diagram of a mine drainage treatment system according to an example of the present invention, FIG. 2 is a schematic perspective view of the slow stirring tank shown in FIG. 1, and FIG. 3 is a schematic plan view of the slow stirring tank of FIG.

1 to 3, the acid mine drainage treatment system 100 according to an embodiment of the present invention includes a pH control tank 10, a rapid stirring tank 20, a slow stirring tank 30, a settling tank 40, A flow sensor 50 and a controller 60 are provided.

The pH adjustment tank 10 is for neutralizing the acid mine drainage discharged from the abandoned mine M through the pipeline p. When the mine drainage is introduced into the pH adjusting tank 10, an alkali neutralizing agent such as slaked lime (solution) and ferrous sulfate is added through the supply line 11. The initial pH of the mine drainage varies depending on the condition of the mine, but it is very low at about pH 3 level. In the pH adjustment tank 10, the mine drainage is adjusted to a pH of 7 to 8.5 to satisfy the discharge standards.

The acid mine drainage neutralized in the pH adjustment tank 10 flows into the stirring tank, but only one stirring tank may be installed, but in this example, it is divided into a rapid stirring tank 20 and a slow stirring tank 30 and disposed sequentially.

In the rapid stirring tank 20, aeration and rapid stirring are performed to promote oxidation of dissolved iron and the like. This allows the soluble iron to be converted into individual particles through oxidation. Chemicals such as coagulant may be selectively introduced through the supply line 21 .

The mine drainage discharged from the rapid stirring tank 20 is introduced into the slow stirring tank 30 . The slow stirring tank 30 also injects the coagulant and the coagulant auxiliary through the supply line 31 , and is stirred slowly compared to the rapid stirring tank 20 . In the slow stirring tank 30, the individual particles generated in the rapid stirring tank 20 are aggregated with each other to form flocs, and the flocs are grown. This is because contaminants can be easily precipitated in a sedimentation tank, which will be described later, only when the flocs grow.

The most important point in the slow stirring process is the amount of time to drain and stir the acid after the coagulant is added. In general, it is most desirable to stir for about 15 to 20 minutes. If the time during which the coagulant and the photoacid drainage are stirred with each other is less than the above time, the flocs are not sufficiently large. On the other hand, if it exceeds 20 minutes, it is necessary to be careful because the large-grown flocs may break again.

However, the problem is that the flow rate of mine drainage changes every time. For example, in the rainy season or when heavy rain occurs, the difference in flow rate is up to 10 times higher than that during drought. Mine wastewater treatment facilities are designed based on a constant flow rate. That is, it is designed to be discharged after staying for about 15 to 20 minutes when the standard flow rate of slow agitation is introduced. Therefore, when the flow rate is less than the design value, the time the mine drainage stays in the slow stirring tank 30 is increased than the reference time, and conversely, when the flow rate is greater than the design cap, the residence time is reduced. As a result, the floc is not formed to a desired level, or the floc grows and then breaks.

In order to solve this problem, the present invention improves the structure of the slow stirring tank to a variable type so that the time for which the light acid drains stays in the slow stir tank, more precisely, the time for the light acid drainage and the stirring time after the coagulant is injected in the slow stir tank can be uniformly adjusted did.

Referring to FIG. 2 , the slow stirring tank 30 used in an example of the present invention includes a body part 31 . The main body 31 is formed to be elongated in one direction, and an inlet portion 37 through which the mine drainage is introduced is formed on one side, and an outlet portion 38 through which the mine drainage is discharged is formed on the other side. A pipeline p is connected to the inlet part 37 and the outlet part 38, respectively.

A plurality of partitions 33 , 34 , 35 are installed in the receiving portion inside the main body 30 . As shown in FIG. 3 , the partitions are alternately arranged in the form 33 and 35 extending from the front to the rear of the main body 30 , and in the form 34 extending from the rear toward the front. As the partitions 33, 34, and 35 are formed in the above shape, as indicated by the arrow in FIG. 3, the mine drainage flows along the zigzag path through the front and rear surfaces of the main body. Agitators 32 are installed in the spaces divided by partitions, respectively. In addition, a coagulant input line 31 is installed in each divided space.

In this embodiment, the coagulant input position is changed according to the flow rate. For example, if the flow rate is small, the mine drainage will be discharged after staying in the slow stirring tank 30 for a long time. In this case, if the coagulant is injected from the first space, it is not preferable because the coagulant and the photoacid drainage are stirred for a long time. Therefore, if the flow rate is small, inject the coagulant in the third or fourth space, and adjust the time for agitation of the coagulant and the photoacid drainage to a level of 15 to 20 minutes. Conversely, if the residence time of the light acid drainage in the slow stirring tank 30 is shortened due to a large flow rate, the stirring time can be adjusted to the level of 15 to 20 minutes by injecting the coagulant from the first space and stirring. In this example, three partitions are installed to form four spaces, but the number of partitions and the degree of division of the space can be determined by considering the maximum and minimum values of the flow rate.

In this example, by adjusting the injection position of the coagulant in the stirring tank, the time during which the photoacid drainage and the coagulant are mutually stirred.

In another example of the present invention, by varying the capacity of the slow stirring tank, it is possible to adjust the agitation time of the acid acid drainage and the coagulant. It will be described with reference to the drawings.

4 is a schematic longitudinal cross-sectional view of the slow stirring tank employed in another example of the present invention, and FIG. 5 is a view for explaining the operation of the slow stirring tank shown in FIG.

4 and 5, the slow stirring tank 70 is provided with a first tank portion 71 having an inlet portion and an outlet portion formed on one side and the other side, respectively. A pipeline (p) connected to the rapid stirring tank and the settling tank is installed at the inlet and outlet, respectively.

A second tank part 72 is installed inside the first tank part 71 . The flange portion 73 is formed in an annular shape from the upper periphery of the second tank portion 72 to the inner peripheral surface of the first tank portion 71 . The flange part 73 is coupled to the second tank part 72 , and a sealing member 74 is interposed between the flange part 73 and the inner peripheral surface of the first tank part 72 .

In this example, the second tank unit 72 is movable up and down in the vertical direction. For example, a piston 76 is coupled to the lower end of the second tank 72 , and a driving unit (not shown) such as a cylinder or a motor for driving the piston 76 is provided. The piston 76 is installed to penetrate the first tank 71 , and the sealing member 75 is also interposed between the piston 76 and the through hole of the first tank 71 .

When the driving unit is operated, the second tank part 72 and the flange part 73 may move up and down as shown in FIG. 5 . When the second tank part 72 is located on the upper part, the space that can accommodate the mine drainage becomes smaller, and on the contrary, when the second tank part descends, the space 79 where the mine drainage is accommodated as shown by the dotted line in FIG. get bigger

If the flow rate is small, the process is performed at the position where the second tank part 72 is raised. Since the second tank 72 is filled with a structure in which the photo-acid drainage is discharged, the time for which the light-acid drainage and the coagulant are stirred can be adjusted to 15 to 20 minutes.

Conversely, if the flow rate is large, the process is performed at the position where the second tank part 72 is lowered. Because the space for receiving the mine drainage becomes larger, the stirring time can be adjusted to 15-20 minutes even if the flow rate is high and the flow rate is high.

Of course, the coagulant injector 77 and the stirrer 78 are installed in the slow stirring tank 70 as well. The stirrer 78 is also movable up and down, so that the stirring position can be set.

In the slow stirring tank 70 employed in this example, the volume of the space in which the light-acid drainage is accommodated is varied to control the time during which the light-acid drainage is stirred with the coagulant. Of course, the injection amount of the coagulant can also be adjusted according to the flow rate.

One thing to consider is, if the purpose of simply changing the mine drainage accommodation space of the slow stirring tank 70 is to install a lifting plate that moves up and down in the first tank part 71 without a separate second tank part, it is considered can However, in this case, the stirring efficiency is reduced. That is, for example, if the flow rate is small and the lift plate is disposed on the upper part, the mine drainage does not form a certain depth and is accommodated in a thin and widely spread form, making it difficult to use the stirrer, as well as lowering the stirring efficiency. It is effective for the agitation to be carried out in a state in which the photo-acid drainage is formed at a constant depth and the stirrer is completely submerged in the light-acid drainage. Therefore, in this example, a second tank part 72 having a certain depth is separately installed to control the stirring time, and stirring efficiency is ensured.

As described above, in the present invention, by adjusting the position at which the coagulant is input in the slow stirring tank or by adjusting the capacity of the slow stirring tank, the time for which the photoacid drainage meets the coagulant and is stirred.

For this, the flow rate must be measured in real time, and the injection location and injection amount of the coagulant must be appropriately determined according to the flow rate. In the present invention, the flow rate sensor 50 is installed to measure the flow rate in real time before the mine drainage is discharged from the abandoned mine M and flows into the pH adjustment tank 10 . The flow rate measured by the flow sensor 50 is transmitted to the controller 60, and the controller causes the flow rate to be stirred with the coagulant for about 15 to 20 minutes in a slow stirring tank. In the case of the example shown in FIGS. 2 and 3 , it is determined from which space the coagulant is injected, and the coagulant feeder is operated. In the case of the example shown in FIGS. 4 and 5, the position of the second tank is adjusted so that the mine drainage can stay for about 15 to 20 minutes in the slow stirring tank. Of course, the amount of coagulant input is also determined.

The mine drainage that has passed through the slow stirring tanks 30 and 70 flows into the settling tank 40 . In the settling tank 40, the flocs (contaminants) formed in the slow stirring tanks 30 and 70 are precipitated as sludge. After the contaminants have settled, the supernatant is discharged to the outside under conditions that satisfy the water quality standards.

As described above, in the present invention, even when the flow rate of the photo-acid drainage changes very significantly, the time for mutually stirring the coagulant and the photo-acid drainage in the slow stirring tank can be kept constant. There is an advantage in that by forming a floe with a sufficient size, contaminants can be easily precipitated and removed.

The protection scope of the present invention is not limited to the description and expression of the embodiments explicitly described above. In addition, it is added once again that the protection scope of the present invention cannot be limited due to obvious changes or substitutions in the technical field to which the present invention pertains.

100... mine drainage treatment system
10 ... pH adjustment tank, 20 ... Rapid stirring tank
30,70 ... Slow stirring, 33,34,35 ... Partition
40 ... settling tank 50 ... flow sensor
60 ... controller 71 ... first tank part
72 ... second tank part, 73 ... flange part
M ... mine (closed mine) P ... pipeline
W ... mine drainage

Claims (6)

a pH adjusting tank for adjusting the pH of the acid mine drainage;
a stirring tank disposed at the rear end of the pH adjusting tank to add a coagulant to the photo-acid drainage to stir, and to adjust the time for the photo-acid drainage to meet the coagulant and stir; and
and a sedimentation tank disposed at the rear end of the stirring tank to precipitate sludge from the mine drainage;
The stirring tank,
A first tank part having an inlet part and an outlet part formed on one side and the other side, respectively, to enable the inflow and outflow of mine drainage;
a second tank unit installed inside the first tank unit and capable of ascending and descending within the first tank unit;
It extends from the upper periphery of the second tank part to the inner circumferential surface of the first tank part, and includes a flange part that can be raised and lowered together with the second tank part. Mine drainage treatment system, characterized in that the increase or decrease.
According to claim 1,
The agitation tank is a mine drainage treatment system, characterized in that it is separated into a rapid stirring tank and a slow stirring tank according to the process sequence. 3. The method of claim 2,
In the slow stirring tank, the acid mine drainage and the coagulant are mutually stirred for 15 to 20 minutes, and then discharged to the settling tank. According to claim 1,
The stirring tank
a body portion arranged long in one direction and having an inlet portion and an outlet portion respectively formed on one side and the other side so that the mine drainage flows in and out;
Partitions respectively extending from the front and rear surfaces of the main body between the inlet and outlet so that the mine drainage forms a zigzag path;
A stirrer installed in each space divided by the partition;
Mine drainage treatment system, characterized in that it comprises a coagulant injector installed in each of the divided spaces. delete According to claim 1,
a flow sensor for measuring the flow rate of the mine drainage;
The light-acid drainage treatment system, characterized in that it further comprises a controller that receives a signal from the flow sensor and adjusts at least one of the injection amount and the injection position of the coagulant to adjust the time during which the light-acid drainage and the coagulant are stirred with each other.

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