KR20110026828A - Treatment system for acid mine drainage and treatment method using thereof - Google Patents

Abstract

PURPOSE: An acidic mine drainage processing system and a processing method using thereof are provided to reduce the usage amount of a neutralizing agent, by reusing the non-reactive neutralizing agent inside a neutralizing tank. CONSTITUTION: An acidic mine drainage processing system comprises the following: a first reactor(20) including a neutralization tank for forming metal precipitates by adding a neutralizing agent to acidic mine drainage; a second reactor(30) connected to the neutralization tank for receiving the acidic mine drainage with the metal precipitates, including a reaction tank for maintaining the dissolution of the non-reactive neutralizing agent inside the mine drainage to precipitate metallic ions; and a sedimentation device(50) including a sludge collector(54) for collecting sludge from the mine drainage to separate water with the sludge.

Description

Acid mine drainage treatment system and treatment method using same {TREATMENT SYSTEM FOR ACID MINE DRAINAGE AND TREATMENT METHOD USING THEREOF}

The present invention relates to a treatment system and method for treating acid mine drainage, and more particularly, to an acid mine drainage treatment system and treatment method capable of economically treating acid mine drainage using neutralizing agents effectively.

Mine was developed to obtain various minerals necessary for human industrial activities. However, due to lack of economics and profitability, a large number of mines are abandoned or abandoned, and there are about 2,000 dormant and abandoned mines in Korea. However, these ore mines are easily left unattended without the installation of appropriate mine prevention facilities, causing serious environmental problems in the surrounding environment. In particular, acid mine drainage, which occurs even in runaway mines, contains low pH and high concentrations of metals, making it a serious source of pollution to surrounding rivers and agricultural land.

Polluted rivers cannot be used as drinking water, agricultural water, or industrial water, and crops harvested from polluted farmland are dangerous because they contain a large amount of metals that are harmful to the human body. Thus, economic losses of farms around the mines may occur.

Global warming is causing abnormal climates, especially droughts and severe water shortages. Therefore, it is necessary to purify and reuse contaminated water.

In general, acid mine drainage is derived from minerals containing sulfur. For example, pyrite is present in coal mines and metal mines, and acid mine drainage is generated by contact with air and contact with rainwater or groundwater by mining activities.

2 FeS₂+ 7O₂+ 2H₂O → 2 Fe²⁺+ 4SO₄ ^2-+ 4H⁺ (One)

4 Fe ²⁺ + O ₂ + 4H ⁺ → 4 Fe ³⁺ + 2H ₂ O (2)

4 Fe³⁺+ 12H₂O → 4 Fe (OH)₃+ 12H⁺ (3)

FeS₂+ 14Fe²⁺+ 8H₂O → 15 Fe²⁺+ 2SO₄ ^2-+ 16H⁺ (4)

4 FeS₂+ 15O₂+ 14H₂O → 4 Fe (OH)₃+ 8H₂SO₄ (5)

The above reaction scheme shows the formation of acid mine drainage and is faster by iron oxidizing bacteria or sulfated bacteria.

In addition, ferrous ions (Fe ²⁺ ) and hydrogen ions are generated when sulfides such as pyrite are dissolved in water while being oxidized as in Scheme (1). The produced ferrous ions are oxidized to ferric ions (Fe ³⁺ ) by reacting with dissolved oxygen as shown in Scheme (2). Because dissolved oxygen is consumed in these reactions, dissolved oxygen in the drainage is reduced, creating anaerobic conditions in which the fauna and flora of the river cannot live.

When the produced ferric ion is introduced into the stream, hydrogen ions are generated as in Scheme (3) to increase the pH of the solution. Iron hydroxide (4 Fe (OH) ₃ ) precipitates according to this reaction, and the bottom of the river becomes red and causes aesthetic problems as well as the health of the river.

Hydrogen ions produced in Schemes (1) and (3) lower the pH of the mine drainage and make the drain acidic. Lower pH accelerates the dissolution of metals in the mineral and increases the metal content of the drains.

Reaction equations (4) and (5) show a process in which iron sulfide and ferrous ions react together with water to generate hydrogen ions and iron hydroxide precipitates, and even through this scheme, drainage becomes acidic and red precipitates are formed. It can be seen that.

As described above, the method for treating oxidized mine drainage is divided into active treatment and passive treatment depending on power and continuous use of chemicals.

Among the passive treatment methods, the most frequently used method in Korea is firstly treated with sulfate reducing bacteria and limestone in SAPS (Sucessive Alkalinity Producing System), and then has the structure of secondary and tertiary treatment through oxidizing tank and marsh. However, the initial installation costs are high, and large sites are required to discharge the wastewater to an appropriate level. In the case of mines located in the mountains, there is a problem of damaging the mountains in order to prepare a large-scale site for passive treatment, and flooding or typhoons due to the need to install oxidizing tanks or marshes on mountain slopes that are not easily accessible. There is a vulnerable problem.

In addition, the active treatment method can treat the mine drainage in a short time by using chemicals, but a large amount of chemicals are used because the amount of chemicals required when the pH is low or the iron content is high There is a problem that the wastewater treatment cost is very high. In addition, a large amount of sludge is generated by the use of excessive chemicals, there is a problem that must be treated.

In particular, in the active treatment, mainly used slaked lime injected into the slurry or powder as a chemical, due to the low solubility of the slaked lime is not used a large amount of slaked lime is discharged to the sludge has a problem of high treatment cost.

In the present invention, when the large-scale site composition is difficult and the active treatment method should be used, the oxidizer and the first reaction device to increase the oxidation degree of the drainage so that the unreacted neutralizing agent can be used continuously, and the second reaction is continued. It is an object of the present invention to provide an acid mine drainage treatment system and treatment method capable of minimizing the use of chemicals by reducing the unreacted neutralizer in the discharged sludge by continuously providing a second reaction device and a precipitation device.

In order to achieve the above object, the present invention comprises a first reaction device including a neutralization tank for forming a metal precipitate by adding a neutralizer to the acid mine drainage; A second reactor connected to the neutralization tank of the first reactor and including a reactor for introducing the wastewater in which the metal precipitate is formed and continuing dissolution of the unreacted neutralizer in the wastewater to precipitate metal ions remaining in the wastewater; ; And a precipitation device connected to the reaction tank of the second reactor, the sedimentation tank having a sludge collector for separating the sludge and the water by collecting the sedimentation tank and the precipitated sludge into which the drainage of the reactor flows and precipitates the sludge of the metal deposit of the drainage. It provides a mine drainage treatment system comprising a.

Preferably, the first reactor further includes an air injector for aeration of the wastewater in the neutralization tank, and the second reactor further includes an air injector for aeration of the wastewater in the reactor.

The first reactor further comprises a stirring device for stirring the inside of the neutralization tank to maintain the slurry state, the second reactor is preferably further comprises a stirring device for stirring the inside of the reactor to maintain the slurry state Do.

A pH measuring device including a first sensor installed in the neutralization tank and measuring a pH in the neutralization tank and a second sensor installed in the reaction tank and measuring pH in the reaction tank; The control unit may further include a control unit for adjusting the amount of the neutralizing agent injected into the neutralization tank according to the pH of the neutralization tank and the reaction tank measured by the pH meter, wherein the control unit adjusts the neutralizing agent injection amount so that the pH of the neutralization tank is 6 to 10. I can regulate it.

The sludge collected in the sludge collector of the precipitation apparatus is preferably returned to the first reactor and reused.

A flocculant is added to the precipitation tank to accelerate the precipitation rate of the metal precipitate.

The sludge collected in the sludge collector of the precipitation apparatus is preferably returned to the first reactor and reused in the first reactor.

The neutralizing agent preferably comprises at least one from the group consisting of hydrated lime, quicklime, calcium carbonate, sodium hydroxide, potassium hydroxide, magnesium hydroxide, sodium carbonate, concrete, carbonic acid, starfish, ash and dolomite.

An oxidation tank further located upstream of the neutralization tank of the first reactor so that the reaction of the neutralizing agent in the first reactor is oxidized to oxidize the acid mine drainage before the acid mine drainage enters the neutralization tank. It is preferred to further comprise means.

Preferably, the oxidizing means further includes an air injector for aeration of the drainage inside the oxidizing tank and a stirring means for stirring the inside of the oxidizing tank.

In addition, the present invention is an oxidation step of aeration by oxidizing the incoming mine drainage; A neutralization step of injecting a neutralizing agent into the oxidized mine drainage; A reaction step of continuously reacting the unreacted neutralizing agent and the remaining metal ions remaining in the drained water after the neutralization step; A mine drainage treatment method comprising a precipitation step of separating the water and sludge from the wastewater undergoing the reaction step.

It is preferable to further include a sludge reuse step of returning the sludge precipitated in the precipitation step to the multiple of the neutralization step.

In order to accelerate the precipitation rate in the precipitation step, it is preferable to inject a flocculant into the drainage after the reaction step and before the precipitation step.

According to the present invention, it is possible to treat the mine drainage in a short period of time without adding a neutralizer to form a large-scale site, while having a second reactor for continuously reacting the first reactor using the neutralizer and the unreacted neutralizer. By minimizing the amount of use by increasing the use efficiency of the unreacted neutralizing agent, the cost of mine drainage treatment can be significantly reduced.

In addition, the final precipitated sludge is returned to the neutralization tank to reuse the unreacted neutralizing agent, thereby reducing the amount of neutralizing agent used.

In addition, there is another effect of minimizing the precipitate by the use of neutralizers because the amount of neutralizer used is reduced.

Hereinafter, an acid mine drainage treatment system and an acid mine drainage treatment method using the same will be described in detail with reference to FIGS. 1 to 5.

1 is a schematic diagram showing an acid mine drainage treatment system according to the present invention. As shown in FIG. 1, this embodiment includes an oxidation apparatus 10 having an oxidizing tank for oxidizing a mine drainage 1 to oxidize ferrous iron (Fe ²⁺ ) ions present in the mine drainage to ferric iron (Fe ³⁺ ). )Wow; The first reactor 20 having a neutralization tank connected with an oxidizing tank of the oxidizing apparatus 10 to inject oxidized wastewater from the oxidizing tank, and a neutralizing agent 61 is added to neutralize the mine drainage and generate a precipitate of metal. ; A second reactor 30 connected to the neutralization tank and having a reaction tank for continuously reacting the unreacted neutralizing agent present in the sludge type mine drainage including the precipitate produced in the neutralization tank; It comprises a precipitation device 50 having a precipitation tank for separating the sludge from the slurry produced in the reaction tank.

The oxidizing apparatus 10 further includes an air injector 13 which increases the amount of dissolved oxygen by aeration of the drainage in the oxidizing tank to promote oxidation, and an agitator 12 which stirs the supplied oxygen and the drainage. The air injector 13 or the stirrer 12 may be selectively provided according to the consumption amount of oxygen or the volume of the oxidizer. That is, if oxygen is evenly distributed in the oxidizer by only air injection, the air injector 13 may be excluded, and when the amount of oxygen consumed is small, the air injector 13 may be excluded.

The proper air injection speed of the air injector 13 varies depending on the capacity of the drainage and the properties of the mine drainage, but is preferably 0 to 3 m ³ / min. .

Metals present in acid mine drainage include common materials such as iron, manganese and aluminum and heavy metals such as zinc, copper, cadmium, lead, arsenic, mercury, and radioactive materials such as uranium. Most metals combine with hydroxide ions at pH 5-7 to form insoluble precipitates. Therefore, in order to remove the metal in the acid mine drainage, the acid mine drainage must be neutralized to form a metal precipitate. Therefore, the neutralizing agent for precipitating the metal is adjusted by adjusting the pH of the acid mine drainage in the first reactor 20. The neutralizing agent used may be an alkaline substance that consumes acidity such as slaked lime, quicklime, calcium carbonate, sodium hydroxide, potassium hydroxide, magnesium hydroxide, sodium carbonate, concrete, magnesium carbonate, starfish, ash and dolomite, and is also used as a mixture. This is possible. There is also a method of directly injecting the neutralizing agent into the reaction tank of the first reactor 20, there is also a method of injecting in a sludge state.

The first reactor 20 is connected with a neutralizer feeder 60 that supplies a neutralizer. The neutralizing agent feeder 60 is prepared in a slurry state by mixing the neutralizing agent 61 and the fresh water 91 in a weight ratio of 0.5 to 20% neutralizing agent. The neutralizing agent feeder 60 may be provided with a stirring device 62 to uniformly mix the fresh water 91 and the neutralizing agent 61 to maintain a slurry state without separating solids.

In the first reaction device 20, the pH is less than 6 and the precipitation effect drops sharply, and in the case of 10 or more, an excessive amount of neutralizing agent is added to generate a considerable amount of unreacted neutralizing agent, so that the pH measuring device 80 may include the first reaction device (20). It is preferable to adjust the pH inside the neutralization tank of 6) to 6-10. It is connected to the pH meter 80 for measuring the pH of the neutralization tank of the first reactor (20). In the neutralization tank, the first sensor 81 of the pH meter 80 is installed.

In the first reactor 20, an agitation device 22 and an air injector 23 are installed to accelerate an oxidation reaction or a neutralization reaction and maintain a slurry state in the neutralization tank. When the ferric ion content of acid mine drainage is high (30 mg / L or more), dissolved oxygen is rapidly consumed when a neutralizing agent is added. Thus, a completely unoxidized precipitate is produced, such as cyan ferrous hydroxide. When the precipitate is not completely oxidized as described above, the continuous consumption of oxygen is made in the reactor of the second reactor 30 and the precipitation tank of the precipitation device 50, and the precipitation efficiency in the precipitation device 50 is lowered. Therefore, the neutralization tank of the first reactor 20 is also provided with an air injector 23 for aeration inside the neutralization tank to assist oxidation of the drainage water.

Since the sludge generated in the precipitation apparatus 50 contains a considerable amount of unreacted neutralizing agent, the reused sludge 94 may be returned to the neutralization tank of the first reactor 20 for injection.

When using slaked lime or quicklime used as a neutralizing agent for treating the mine drainage, the neutralizing agent is continuously injected into the first reactor 20 to adjust the required pH. However, in the first reactor 20, the mine drainage is continuously introduced from the oxidizer 10, and the produced sludge reacted with the neutralizer is continuously discharged. Therefore, since the mixed reaction does not occur in the first reactor, the unreacted neutralizing substance remains in the effluent flowing out of the first reactor 20 in a considerable amount.

In the second reactor 30, the pH may be increased without additional neutralizer through the unreacted neutralizer present in the effluent of the first reactor 20. Like the oxidizer 10 or the first reactor 10, the second reactor 30 also includes an air injector 33 and an agitator that aeration conditions inside the reactor in order to create oxidation conditions and maintain the inside of the reactor in a slurry state. 32).

The amount of neutralizing agent to be injected into the first reactor 20 may be determined by measuring the pH in the reactor of the second reactor 30. The pH in the reactor is to minimize the amount of unreacted neutralizing agent. Therefore, a second sensor 82 connected to the pH meter 80 and measuring the pH in the reactor of the second reactor 30 is installed in the reactor. The pH meter 80 is connected to a control unit (not shown) to control the operation of the neutralizing agent supply 60 to adjust the injection amount of the neutralizing agent.

The drainage residence time in the first reactor 20 and the second reactor 30 is determined according to the characteristics of the mine drainage, that is, the pH of the mine drainage, ferrous ions, total metal concentration and the kind of neutralizing agent. If the pH of the mine drainage is low or the ions of the dissolved metal are high, a long residence time is required. If the pH of the mine drainage is high or the amount of dissolved metal is small, a small residence time is required. This may vary depending on the nature of the mine drainage and the type of neutralizer. The residence time of the mine drainage of the first reactor 20 may be about 1 minute to 30 minutes, and the residence time of the mine drainage of the second reactor 30 may be about 10 minutes to 240 minutes. Among the neutralizing agents, neutralizing agents having a relatively fast solubility and high reactivity such as sodium hydroxide, slaked lime and potassium hydroxide need a relatively short residence time, while a low solubility and low reactivity neutralizing agents such as magnesium hydroxide and potassium carbonate have a relatively long residence time. This is necessary.

Coagulant 71 may be administered to increase the sedimentation of sludge generated in the mine drainage treatment system. The coagulant 71 is manufactured in the coagulant injector 70, and the fresh water 91 is supplied to the coagulant injector 70, and the coagulant and the fresh water are mixed by the stirrer 72. The flocculant 71 is introduced into the effluent of the second reactor 30 to promote precipitation in the precipitation device 50. Coagulant dosing device 70 is connected to the coagulation chamber 40 between the second reactor 30 and the precipitation device 50, the coagulant mixed with fresh water in the coagulation chamber 40 is the second reaction device 30 Mixed with the effluent flowing out of the reactor. The coagulation chamber 40 is to have a residence time sufficient to separate the sludge from the precipitation device 50 to increase the sedimentation of the sludge. Therefore, it can be excluded when the metal concentration of the effluent is sufficiently reduced.

Precipitation apparatus 50 is a means for separating the sludge from the slurry generated in the second reactor 30 and the coagulation chamber 40, to separate the sludge and discharge the effluent. The sludge collector 54 is installed in the precipitation device 50 to collect the sludge. The sludge collector 54 of the sedimentation device 50 is a device such as a central rotary shaft sedimentation basin, a rectangular sedimentation basin, and a high speed sedimentation basin according to the collection method thereof. The sludge produced in the precipitation device 50 is reused sludge 94 and sludge treatment means (not shown) returned to the first reactor 20 to the oxidizer 10 in order to continuously use the unreacted neutralizing agent. The final sludge to be sent is divided into 93. In this way, the final drainage 95 from which the sludge is removed is discharged.

When the sludge generated in the precipitation apparatus 50 is returned to the reaction tank of the first reactor 20 to reuse the sludge and increase the oxidation rate of ferrous ions, the returned sludge is within 20% of the solid content. It is preferable to contain. This is because the volume of the precipitation device 50 must be very large in order for the solid content of the sludge to exceed 20%.

Figure 2 shows another embodiment of the acid mine drainage treatment system according to the present invention. 2 is an example in which the oxidizer is excluded from the embodiment of FIG. 1.

When the acidity of acid mine drainage is very high or the concentration of metals is very high and the alkalinity of mine drainage is low, the net acidity becomes high. In this case, the oxidation efficiency is very low without the addition of a neutralizing agent, which lowers the utility of the oxidizer. Therefore, since the oxidizer 20 alone does not exert its utility, the neutralizer is added to the first reactor 20 without the oxidizer, and the rest of the process is the same as that of the embodiment of FIG.

The gangsu water generated in the Yeongdong coal mine located in Imgok-myeon, Gangneung-si, Gangwon-do, Korea was treated using the acid mine drainage treatment system designed by the present invention. The pH of the mine water was between 4.5 and 6.2 and the net acidity was between 350 and 450 mg CaCO ₃ / L. The concentration of ferric ions dissolved in the mine water was 175 to 275 mg / L, the total iron concentration was 209 to 284 mg / L, the total aluminum concentration was 5 to 28 mg / L, and the total manganese concentration was 2 to 5 mg / L.

The acid mine drainage treatment system for treating the mine water includes an oxidizing device 10 having an oxidation tank of 1 m ³ , a first reaction device 20 for separating a 230 L neutralization tank, and a second reaction having a reaction tank of 230 L. A device 30 and a 1 m ³ settling device 50. The oxidizer 10 is provided with an air injector 13 capable of injecting air at 600 L / min, and the first and second reactors 20 and 30 are provided with an air injector through diffuser stones. It was installed to enable aeration of 300 L / min.

Neutralizer feeder (60) is a hydrated lime at 6% by weight in a 200L capacity tank to produce the slaked lime sludge through continuous stirring. The neutralizing agent was added to the first reactor 20 to produce the slaked lime sludge thus prepared, and the acid mine drainage of the neutralization tank of the first reactor 20 and the reactor of the second reactor 30 was maintained at 6 to 10 pH. To control.

The precipitation device 50 used a circular sedimentation battery with a sludge collector 54. The first reactor 20 and the second reactor 30 are attached with a stirrer for rapid reaction, the oxidizer 10 is agitated through the aeration of air without a separate stirrer.

The drainage residence time in the oxidizer 10 was set to 1 hour, and the drainage residence time in the first reactor 20 and the second reactor 30 was 13.8 minutes, respectively. The residence time was set to 1 hour.

Adjusting the pH of the neutralization tank to 7, 7.5, 8 is shown in Figures 3 to 5.

Figure 3 is a graph showing the pH change of the waste water in the process of processing through the acid mine drainage treatment system as described above, Figure 4 is a graph showing the content of ferric ions (Fe ^{2 +} ) in the drain, 5 is a graph showing the total iron ion content in the wastewater.

When the air is injected into the first reactor 20 and the second reactor 30 and the aeration is not performed, the experiment was performed by dividing the pH of the first reactor 20 into three groups of 7.5, 8, and second. The pH of the reactor 30 was 0.3 to 0.9 higher than that of the first reactor 20, and the iron removal capacity was 95% to 98% in the first reactor 20, but 98 in the second reactor 30. % To 100%. Since the pH of the wastewater discharged from the reaction tank and the settling tank is higher than the pH of the neutralizing tank, the amount of neutralizing agent can be reduced by reusing it.

On the other hand, when air is injected into the first reactor 20 and the second reactor 30 at 150 L / min, as a result of adjusting the first reactor 20, the pH of the second reactor is 1 0.7 to 1.2 was higher than the reaction device, iron removal capacity was 98% to 99% in the first reactor 20, but was 100% in the second reactor (30).

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and it is common in the field of the present invention that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

1 is a block diagram schematically showing an embodiment of a mine drainage treatment system according to the present invention;

2 is a block diagram schematically showing another embodiment of the mine drainage treatment system according to the present invention;

Figure 3 is a graph showing the pH change in the drain in the process of processing mine drainage using the mine drainage treatment system according to the present invention,

Figure 4 is a graph showing the change in the content of the first iron ion in the drain in the process of processing mine drainage using the mine drainage treatment system according to the present invention,

Figure 5 is a graph showing the change in the total iron ion content in the drain in the process of processing mine drainage using the mine drainage treatment system according to the present invention,

<Description of the symbols for the main parts of the drawings>

10: oxidizer 20: first reactor

30: second reaction autonomous 40: coagulation chamber

50: precipitator 60: neutralizer feeder

70: flocculant administration 80: pH meter

91: fresh water 93: final sludge

94: reused sludge 95: final drainage

Claims (16)

A first reactor comprising a neutralization tank for introducing a neutralizer into an acid mine drainage to form a metal precipitate; A second reaction device connected to the neutralization tank of the first reaction device, the second reaction device including a reaction tank into which the waste water in which the metal precipitates are formed flows and continues dissolution of the unreacted neutralizing agent in the waste water to precipitate metal ions remaining in the waste water; ; And A precipitation device connected to the reaction tank of the second reactor, including a sedimentation tank into which the drainage of the reaction tank flows in and depositing the sludge of the metal precipitates of the drainage, and a sludge collector for separating the sludge and water; Mine drainage treatment system comprising a. The method of claim 1, The first reactor further comprises an air injector for aeration of the drainage in the neutralization tank. The method of claim 1, And the second reactor further comprises an air injector for aeration of wastewater in the reactor. The method of claim 1, The first reactor further comprises a stirring device for stirring the inside of the neutralization tank to maintain a slurry state. The method of claim 1, The second reactor is a mine drainage treatment system further comprises a stirring device for stirring the inside of the reactor to maintain a slurry state. The method of claim 1, A pH measuring device including a first sensor installed in the neutralization tank and measuring a pH in the neutralization tank and a second oath installed in the reaction tank and measuring pH in the reaction tank; Control unit for adjusting the amount of neutralizing agent injected into the neutralization tank according to the pH of the neutralization tank and the reaction tank measured by the pH meter Mine drainage treatment system further comprising. The method of claim 6, The control unit is a mine drainage treatment system for adjusting the injection amount of the neutralizer so that the pH of the neutralization tank is 6 to 10. The method of claim 1, The sedimentation tank is injected into the sedimentation tank mine drainage treatment system to accelerate the sedimentation rate of the metal precipitate. The method of claim 1, The sludge collected in the sludge collector of the precipitation apparatus is returned to the first reactor and reused in the first reactor. The method of claim 1, The neutralizing agent comprises at least one from the group consisting of hydrated lime, quicklime, calcium carbonate, sodium hydroxide, potassium hydroxide, magnesium hydroxide, sodium carbonate, concrete, carbonic acid, starfish, ash, dolomite. The method according to any one of claims 1 to 10, An oxidation tank further located upstream of the neutralization tank of the first reactor so that the reaction of the neutralizing agent in the first reactor is oxidized to oxidize the acid mine drainage before the acid mine drainage enters the neutralization tank. A mine drainage treatment system further comprising means. The method of claim 11, The oxidation means further comprises an air injector for aeration of the drainage in the oxidizing tank. The method of claim 11, The oxidation means further comprises a stirring means for stirring the inside of the oxidation tank. An oxidation step of aeration of the incoming mine drainage; A neutralization step of injecting a neutralizing agent into the oxidized mine drainage; A reaction step of continuously reacting the unreacted neutralizing agent and the remaining metal ions remaining in the drained water after the neutralization step; Precipitation step of separating the water and sludge from the wastewater undergoing the reaction step Mine drainage treatment method comprising a. The method of claim 14, And a sludge reuse step of returning the sludge precipitated in the precipitation step to the waste water of the neutralization step. The method of claim 14, And a step of injecting a flocculant into the wastewater after the reaction step and before the precipitation step in order to accelerate the precipitation rate in the precipitation step.

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