KR100618305B1 - In-Adit-Sulfate-Reducing System - Google Patents

Abstract

The present invention is disposed on the discharge path of the acid mine drainage discharged from the abandoned mine containing a large amount of heavy metal and sulfate ions to neutralize the acid mine drainage and to precipitate heavy metals contained therein (In- Adit-Sulfate-Reducing System (IASRS). In the mine sulphate reduction facility according to the present invention, the organic material layer is filled with the organic material consisting of CH ₂ O, and the sulfate ion contained in the acid mine drainage, the organic material is supported on the organic material, the organic material as an electron donor In order to maintain the temperature of the organic material layer which carries the said sulfate reducing bacterium, the sulfate reducing bacterium which functions to reduce this sulfate ion, produces | generates alkalinity, and neutralize this acid mine drainage is carried out. The organic layer is installed in the tunnel of the abandoned mine, and thus the temperature of the organic layer is kept constant so that the metabolic action of the sulfate reducing bacterium supported in the organic layer is active, thereby reducing the sulfate, precipitation of heavy metal ions, and neutralization of acid mine drainage. Will be done efficiently.

Acid Mine Drainage, Sulfate Reducing Bacteria

Description

In-Adit-Sulfate-Reducing System

1 is a schematic diagram of a conventional natural purification facility of acid mine drainage.

Figure 2 is a schematic diagram of a mine sulphate reduction facility according to a first embodiment of the present invention.

FIG. 3 is a schematic view for explaining the structure of the mine sulfate reduction facility shown in FIG.

4 is a cross-sectional view taken along the line IV-IV of FIG. 3.

5 to 9 show the experimental results of the mine shaft reduction facility according to the first embodiment of the present invention shown in Figure 2, Figure 5 relates to the neutralization efficiency, Figure 6 relates to the precipitation efficiency of the solid FIG. 7 relates to chemical oxygen demand, FIG. 8 relates to the loading efficiency of iron, and FIG. 9 relates to the precipitation efficiency of aluminum.

10 is a schematic view for explaining the structure of the sulphate reduction facility in the mine according to the second embodiment of the present invention.

11 to 14 show the experimental results of the mine shaft reduction facility according to the second embodiment of the present invention shown in Figure 10, Figure 11 relates to the neutralization efficiency, Figure 12 relates to the iron removal rate, Figure 13 relates to the aluminum removal rate, and FIG. 14 relates to the removal rate of the sulfate.

15 is a schematic view for explaining the structure of the sulphate reduction facility in the pit according to the third embodiment of the present invention.

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

M ... Abandoned Mine A ... Acid Mine Drainage

P ... tunnel 10 ... organic layer

11 ... organics 12,13,14,15 ... organic packed bed

32,33,34,35,36 ... bulkhead 42,43,44,45 ... vent hole

50 ... limestone 60 .. gravel layer

70 ... observer 80 ... limestone layer

90 ... sedimentation tank W ... discharge route of acid mine drainage

The present invention relates to an In-Adit-Sulfate-Reducing System (IASRS) for purifying acid mine drainage, and more particularly, by maintaining a constant temperature regardless of temperature change. The present invention relates to a mine sulphate reduction facility that is effective in preserving the environment and efficiently solves the lack of facility sites by efficiently performing precipitation of heavy metals contained in acid mine drainage and neutralization of acid mine drainage.

Environmental pollutions caused by mines and abandoned mines include ground subsidence, river burial due to loss of waste-rock and tailings, heavy metal contamination of soils, and water pollution by shaft runoff and waste-rock leachate. In particular, the problem of water pollution by acid mine drainage from underground coal mine waste-rock piles has started to be serious since the mid-1990s.

Acid mine drainage is formed when sulfide minerals such as pyrite (FeS ₂ ) and ferrite (FeS) exposed to the atmosphere are oxidized by reaction with oxygen and water, and have a low pH, resulting in acidity, iron, aluminum, and manganese sulfate. It is characterized by high metal content.

The oxidation of pyrite is given by the following equations.

FeS ₂ + 7 / 2O ₂ + H ₂ O → Fe ²⁺ + 2SO ₄ ^2- + 2H ⁺

Fe ²⁺ + 1/4 O ₂ + H ⁺ → Fe ³⁺ + 1/2 H ₂ O

Fe ³⁺ + 3H ₂ O → Fe (OH) _{3 (s)} + 3H ⁺

FeS ₂ + Fe ³⁺ + 8H ₂ O → 15Fe ²⁺ + 2SO ₄ ^2- + 16H ⁺

As shown in the above equation, pyrite is oxidized to generate iron ions and sulfate ions and to be acidified by hydrogen ions.

The acid mine drainage has high mobility of toxic heavy metals due to its low pH and contaminates the surrounding surface and groundwater, destroying the aquatic ecosystem, and the metal ions are oxidized and precipitated with metal hydroxides such as Fe (OH) ₃ . Reddish brown or white precipitates are generated (yellow boy phenomenon) to harm the aesthetics. This acid mine drainage purification method is largely divided into active treatment (active treatment) and passive treatment (passive treatment). Active treatment methods include pH adjustment using ionizing agents, ion exchange and adsorption, flocculation, and filtration. Representative active treatment methods include reverse osmosis, ion exchange, and electrodialysis. However, this active treatment method has a high treatment efficiency but requires a high amount of equipment, chemicals, personnel, and power. Therefore, the maintenance cost is high. Therefore, a passive treatment method that requires very little facility investment and maintenance costs compared to the active treatment method. It is used a lot. Such passive treatments include neutralization treatment using limestone, such as ALDs (anoxic limestone drains) and OLD (oxic limestone drains), aerobic and anaerobic artificial marshes, and advanced alkalinity-producing systems (SAPS) or RAPS that have developed them. There is this. The structure of SAPS among these passive treatment methods is shown in FIG.

Referring to Figure 1, the SAPS system forms a large pond-like tank (2, 상 에) on the discharge path of the acid mine drainage, laid a limestone layer (L) in the lower part of the tank (2) and the limestone layer ( The organic material layer (O) is stacked on top of L). The organic material layer (O) is filled with an organic material consisting of CH ₂ O. Such organic materials are used as mushroom compost, sawdust or sewage sludge. On the other hand, the organic material layer (O) is supported on the sulfate reducing bacteria (SRB: surfate reducing bacteria, not shown). The sulfate reducing bacterium is a microorganism commonly found in a reducing environment in which sulfates and organic matters around us are sufficient, and disulfate bacters (acetate oxidizers) that use fatty acids, especially acetic acid, as a carbon source while reducing sulfates to hydrogen sulfide ( Desulfabactor, Desulfosarcina, Desulfonema, etc. Desulfovibrio as a non-acetate oxidizers using lactate, pyruvate, ethanol, etc. , Desulfomonas, Desulfotomaculum and the like. In the SAPS system of the above configuration, the acid mine drainage is discharged from the tunnel to the outside and flows into the upper portion of the SAPS system to flow downward along the vertical direction. That is, the acid mine drainage flows into the limestone layer L through the organic material layer O, and is discharged along the conduit T connected to the limestone layer L. As the acid mine drainage passes through the SAPS system, by the metabolism of the sulfate reducing bacterium, the sulfate in the acid mine drainage is reduced to hydrogen sulfide and generates alkalinity, and the metal ions in the acid mine drainage combine with hydrogen sulfide to precipitate. The purification is performed.

However, the conventional SAPS system has a problem that the efficiency is different depending on the temperature conditions.

That is, the sulfate reducing bacteria can operate from -7 degrees Celsius to 75 degrees Celsius, but rarely reduce the sulfate in a low temperature environment. At 20 degrees Celsius or 36 degrees Celsius, up to 87% of sulfate ions in acid mine drainage were removed and the activity of sulfate reducing bacteria was very active. However, at 1 degrees Celsius, sulfate ions were hardly removed. Therefore, although the sulfate reducing bacterium may survive in a low temperature environment, the activity of reducing sulfate is almost stopped. In Korea, the average weather is less than 10 degrees Celsius from mid-October to early April, and the locations of the abandoned mines are all mountainous, and temperatures are much lower. Therefore, sulfate reducing bacteria in the domestic natural purification facilities using the SAPS system is difficult to function properly in winter, and thus the acid mine drainage is not purified at all and discharged to the outside causing serious environmental problems. have.

On the other hand, these natural purification facilities need a large space. The area of natural purification facilities currently in operation is approximately 500m ² ~ 6070m ² . In some of the abandoned mine areas, such facilities are not secured outside the mine shafts, and no purification facilities can be set up.In the abandoned mine areas, the natural affection of acid mine drainage is due to domestic sentiment for land. There is a problem with the installation.

The present invention is to solve the above problems, it is possible to generate a constant efficiency irrespective of the change in temperature conditions according to the season, and an object of the present invention is to provide a sulphate reduction facility in the gang designed to facilitate the installation site.

In-Adit-Sulfate-Reducing System (IASRS) according to the present invention for solving the above object is disposed on the discharge path of the acid mine drainage discharged from the abandoned mine containing a large amount of heavy metal and sulfate ions. To neutralize the acid mine drainage and precipitate heavy metals contained therein, wherein the organic material layer is filled with an organic material consisting of CH ₂ O and the organic material, and the organic material is an electron donor and the acid mine The organic material layer which carries the said sulfate reducing bacterium which contains the sulfate reducing bacterium which functions to reduce this sulfate ion and generate an alkali degree, and neutralize this acid mine drainage using the sulfate ion contained in wastewater as an electron acceptor. In order to maintain the temperature of the organic layer, the organic layer is installed in the tunnel of the abandoned mine. It is characterized by.

According to the present invention, the organic material layer is composed of a plurality of organic material filling layers arranged in sequence along the discharge path of the acid mine drainage, so that the plurality of organic material filling layers arranged in order to be isolated from each other, Partition walls are provided between the layers, and the discharge holes penetrating the partition walls are arranged along the plurality of partition walls arranged in order so that the discharge path of the acid mine drainage passing through the plurality of organic material filling layers becomes a wave shape. It is preferable to form alternately in the lower part.

In addition, according to the present invention, in order to neutralize the acid mine drainage flowing into the plurality of organic compound layers, the limestone is included in the organic material packed layer located on the most upstream side of the discharge path of the acid mine drainage of the plurality of organic matter filling layer. It is desirable to have.

In addition, according to the present invention, it is preferable that the organic material layer is further provided with a gravel layer under the organic material.

In addition, according to the present invention, in order to reinforce the neutralization treatment of the acid mine drainage, it is preferable that a limestone layer in which limestone is further filled on the downstream side of the organic material layer on the discharge path of the acid mine drainage is further provided.

Hereinafter, with reference to the accompanying drawings, it will be described in detail with respect to the sulphate sulfate reduction facility according to the first embodiment of the present invention.

FIG. 2 is a schematic view of a mine sulfate reduction facility according to the first embodiment of the present invention, FIG. 3 is a schematic view for explaining the structure of the mine sulfate reduction facility shown in FIG. 2, and FIG. 4 is IV of FIG. It is sectional view of line IV.

2 to 4, the natural purification facility of the acid mine drainage (A) according to the first embodiment of the present invention is composed of an organic material layer 10, sulfate reducing bacteria, the organic material layer 10 is a constant temperature It is installed in the tunnel P of the abandoned mine M so that it may remain in the range. The temperature in this tunnel P is maintained at 12 degrees Celsius to 15 degrees Celsius regardless of the change of the season.

The organic material layer 10 is filled with the organic material 11. The organic material 11 is represented by the chemical formula CH 2 O, and mushroom compost is used as the organic material 11 in this embodiment. In addition to mushroom compost can be a mixture of rice straw and manure, sawdust, oak compost, oak bark, pine needles, sewage sludge, paper sludge, dairy residues, etc., may be used a mixture of these. In addition, the organic material layer 10 is composed of a plurality of organic material filling layer, it consists of three in this embodiment. That is, along the discharge path W of the acid mine drainage A, the first organic packed layer 12, the second organic packed layer 13, and the third organic packed layer 12 are sequentially disposed from an upstream side of the discharge path W. The organic material filling layer 14 is disposed.

In addition, a limestone layer 80 is provided on the downstream side of the third organic matter filling layer 14 on the discharge path W of the acid mine drainage A. This limestone layer 80 is for neutralizing the acid mine drainage A, and is filled with limestone. The limestone layer 80 neutralizes the acid mine drainage (A) by consuming protons and producing HCO 3 − when limestone is dissolved. Expressed by the chemical formula is as follows.

_{^{CaCO 3 + H + → Ca 2+}} + HCO 3 -

Partition walls 32 and 33 are provided between the plurality of organic material filling layers 12, 13, and 14 so that the plurality of organic material filling layers 12, 13, and 14 are isolated from each other. That is, the first partition 32 is installed between the first organic filler layer 12 and the second organic filler layer 13, and between the second organic filler layer 13 and the third organic filler layer 14. Two partitions 33 are provided. In addition, a third partition 34 is provided between the third organic filler 14 and the limestone layer 80 so that the third organic filler 14 and the limestone layer 80 are isolated.

Meanwhile, discharge holes 42, 43, and 44 are formed in the partitions 32, 33, and 34. The discharge holes 42, 43, and 44 are for allowing acid mine drainage A to flow through the partitions 32, 33, 34, and between the two sides of the partitions 32, 33, 34. It is formed through. In addition, the discharge path (W) of the acid mine drainage (A) which sequentially passes through the plurality of organic material filling layers (12, 13, 14) and limestone layer 80 may be a wave (wave) type. The discharge holes 42, 43, and 44 are alternately disposed at upper and lower portions of the partition wall along the discharge path W. In the present embodiment, the acid mine drainage (A) flowing into the organic layer 10 is the first organic filler layer through the inlet hole 19 formed in one lower portion of the first organic filler layer 12. Since it flows into the lower part of the (12), so that the discharge path (W) of the acid mine drainage (A) is a wave shape, the discharge hole 42 is formed in the upper portion of the first partition 32, A discharge hole 43 is formed at a lower portion of the second partition 33, and a discharge hole 44 is formed at an upper portion of the third partition 34.

The plurality of organic material filling layers 12, 13, and 14 are provided with a gravel layer 60 in which gravel 61 is filled under the organic material 11 that is filled. The gravel layer 60 is to provide a space in which the metal precipitates can accumulate when the metal ions present in the acid mine drainage A are precipitated by reacting with hydrogen sulfide. It is formed by the voids.

An observation hole 70 is provided between the second organic filler layer 13 and the indicator of the abandoned mine M, and between the third organic filler layer 14 and the indicator of the abandoned mine M. The observation hole 70 is formed between the organic material filling layers 13 and 14 and the surface of the abandoned mine M. The observation hole 70 newly replenishes the organic material layer 10 to the organic material layer 10 from the surface, or changes the operating state of the facility. Used to check.

The sulfate reducing bacterium is supported on the organic material layer 10. This sulfate reducing bacterium takes the organic matter (11) consisting of CH ₂ O as a feed and progresses the metabolic reaction like the sulfate reducing bacterium of the conventional SAPS system. The sulfate ion (SO ₄ ^2- ) in acid mine drainage (A) becomes an electron acceptor. In this metabolic reaction, sulfates are reduced to produce hydrogen sulfide (H ₂ S) and alkaline (HCO ₃ ⁻ ). Sulfate reduction reaction is represented by the following formula.

^{_{2CH 2 O + SO 4 2- →}} H 2 S + 2HCO 3 -

Hydrogen sulfide (H ₂ S) and alkaline (HCO ₃ ⁻ ) generated by the metabolic reaction of sulfate reducing bacteria react with metal ions (M ²⁺ ) present in the acid mine drainage (A) to form metal sulfides (MS). Precipitate. The chemical equation is:

_{^{M 2+ + H 2 S + 2HCO}} 3 - → MS (↓) + 2H 2 O + 2CO 2

On the other hand, the proton (H ⁺ ) in the acid mine drainage (A) is neutralized by the alkalinity (HCO ₃ ⁻ ), thereby increasing the pH of the acid mine drainage (A). The sulfate reducing bacterium is supported on the organic material layer 10 installed in the tunnel P, and the tunnel P is maintained at 12 to 15 degrees Celsius regardless of the change of seasons and temperatures. Be able to be active.

Hereinafter, the operation of the sulfate reduction facility in the pit according to the first embodiment of the present invention will be described.

The intragranular sulfate reduction facility of the above-mentioned structure is installed in the tunnel P of the abandoned mine M. When the acid mine drainage (A) is discharged from the tunnel (P), the acid mine drainage (A) flows into the gravel layer (60) of the first organic packed layer (12) through the inlet hole (19) and flows upward. After passing through the organic material 11 is introduced into the second organic filler layer 13 through the discharge hole 42 of the first partition wall (32). The acid mine drainage (A) introduced into the second organic filling layer 13 is moved from the upper portion of the second organic filling layer 13 to the lower portion of the discharge hole 43 formed in the second partition wall 33. It is introduced into the lower portion of the third organic filler layer 14 through. Thereafter, the acid mine drainage A is moved upward from the lower gravel layer 60 of the third organic filler layer 14 through the organic material 11. Subsequently, the limestone layer 80 is introduced into the limestone layer 80 through the discharge hole 44 formed in the third partition wall 34, and then discharged to the outside of the sulphate reduction facility through the limestone layer 80. The acid mine drainage (A) passes through the plurality of organic material filling layers (12, 13, 14) and the limestone layer (80), and the discharge path becomes wave-shaped, so that the residence time in the sulphate reduction facility in the gang is increased. . In this process, the acid mine drainage (A) passes through the plurality of organic packing layers (12, 13, 14), as described in detail above, the acid mine drainage (A) is neutralized by the metabolic action of the sulfate reducing bacteria. The sulfate inside is reduced to hydrogen sulfide. The hydrogen sulfide and the metal ions react with each other to precipitate in the gravel layer 60. In addition, the acid mine drainage A is further neutralized in the limestone layer 80. When the organic material 11 needs to be replaced, the organic material 11 may be replaced or supplemented through the observation hole 70.

In order to determine the effect of the natural purification facility according to the first embodiment of the present invention having the above configuration, the first, second, third organic material filling layer 12 in the first embodiment of the present invention as shown in FIG. , 13,14) and the limestone layer 80, the height was 12cm (H), the width was 12Cm (D) and the length was 30Cm (F) to make a model 1 to the experiment. As described above, each of the organic material filling layers 12, 13, 14 and the limestone layer 80 are separated by the partitions 32, 33, 34, and the partition walls have acid mine drainage A flowing in a wave form. Discharge holes 42, 43, and 44 were alternately formed in the upper and lower portions of the 32, 33, and 34. The organic material layer 10 was filled with mushroom compost, and the lower part of the mushroom compost was laid with gravel at a height of 4 cm. The limestone layer 80 was filled with 3000 g of limestone. The packing density of mushroom compost is 1.33 g / Cm ³ , and the limestone packing density is 2.65 g / Cm ³ . The total volume of Model 1 is 17.28 liters. In addition, observation holes 70 were provided in the second organic packed layer 13 and the third organic packed layer 14 to observe changes in pH oxidation-reduction potential of the acid mine drainage (A). Acid mine drainage (A) was prepared by reacting wastewater of Samcheok charcoal Jeongam mining with water, total dissolution solids (TDS) of 1500mg / l, pH was adjusted to 2.8. The artificial acid mine drainage (A) prepared as described above had a mean pH of 2.78, 363.92 mg / l for iron (Fe _T ), 262.50 mg / l for aluminum (Al ³⁺ ), and sulfate (SO _4). ^2- ) contained 2362.01 mg / l. Model 1 thus manufactured was operated between 12 and 15 degrees Celsius to create an environment within the tunnel. In addition, the same model 2 as the model 1 was produced and compared with each other to produce a similar effect in the tunnel by operating in a room temperature environment of 25 degrees Celsius in which the sulfate reducing bacterium can be more active. The artificial acid mine drainage (A) was introduced into Model 1 and Model 2 respectively, and the artificial acid mine drainage (A) was continuously introduced into these models at regular intervals. It was designed to take 8 days to discharge through the model. Eight days after the first artificial acid mine drainage (A) was introduced, the acid mine drainage (A) was passed for the first time through this model, and then acid mine drainage (A) was continuously discharged at regular intervals. The experiment was performed for 80 days. Experimental data analyzing the change in the state of the artificial acid mine drainage (A) discharged through the model 1 and model 2, respectively, is shown in FIGS. 5 to 9. Figure 5 is to determine the neutralization efficiency of the acid mine drainage (A) is shown the pH change over time (date).

Figure 6 relates to the sedimentation efficiency of the solids, the concentration change of the total dissolution solids over time (date) in the acid mine drainage (A) discharged from the model is shown.

Figure 7 relates to the chemical oxygen demand, the change in the chemical oxygen demand with the passage of time (date) of acid mine drainage (A) discharged from the model.

FIG. 8 relates to the loading efficiency of iron and shows the change over time (date) of iron concentration in the acid mine drainage (A) discharged from the model.

 Figure 9 relates to the precipitation efficiency of aluminum, the change over time (date) for the concentration of aluminum in the acid mine drainage (A) discharged from the model is shown.

In the 80-day experiment, as shown in FIG. 5, the pH initially rose to 8 at both Model 1 and Model 2 and stabilized at around 6.5, indicating that even in the tunnel (Model 1), at room temperature (Model 2). Similarly, the neutralization was confirmed well. In the case of total dissolved solids, as shown in FIG. 6 and FIG. 7, the first 20 days showed a very high value, and a large amount of organic matter was initially dissolved in the mushroom compost and included in the acid mine drainage (A). However, as shown in FIG. 7, in the chemical oxygen demand, the concentration of model 1 is about half the level of model 2 at 25 degrees Celsius at the beginning of operation, so that the organic matter of high initial concentration is eluted. Rather, it appears less in Model 1. 8 and 9, iron and aluminum were removed more than 90% in both model 1 and model 2 showed the same efficiency. From these results, even when the natural purification facility is installed in the tunnel, the efficiency is lower than when the natural purification facility is installed in a room temperature environment outside the tunnel at 25 degrees Celsius where the sulfate reducing bacterium can work better. It can be seen that it remains similar. However, when the natural purification facility is installed outside the tunnel, a certain effect can be expected in the summer when the temperature is high, but when the sulfate reducing bacterium becomes inactive due to the rapid temperature drop in the winter, the treatment effect drops rapidly. As described above, there is a problem that can not work as. By utilizing the fact that the temperature in the tunnel remains constant regardless of the change of the season, when the natural purification facility is installed in the tunnel, it is possible to maintain a constant treatment efficiency regardless of the temperature change.

Hereinafter, the sulphate sulfate reduction facility according to the second embodiment of the present invention will be described in detail. On the other hand, the same reference numerals are assigned to the members or parts having the same configuration and function as those shown in FIG. 3 among the members or parts shown in FIG. 10, and the detailed description thereof is omitted.

10 is a schematic diagram for explaining a structure of a second embodiment of the present invention.

Referring to FIG. 10, in the second embodiment, the organic material layer 10 includes four organic material filling layers 12, 13, 14, and 15. That is, the fourth organic filler layer 15 is further provided between the third organic filler layer 14 and the limestone layer 80 of the first embodiment. The fourth organic filling layer 15 is also filled with an organic material (not shown) at the top, and a gravel layer (not shown) is provided below the organic material. In addition, a fourth partition 35 is disposed between the fourth organic filler layer 15 and the third organic filler layer 14 to mutually connect the fourth organic filler layer 15 and the third organic filler layer 14. Isolate. A discharge hole 45 penetrating both sides of the fourth partition wall 35 is formed in the upper portion of the fourth partition wall 35. A third partition 34 is provided between the fourth organic filler layer 15 and the limestone layer 80 so as to isolate the fourth organic filler layer 15 and the limestone layer 80 from each other. A discharge hole 44 penetrating both surfaces of the third partition wall 34 is also formed under the third partition wall 34.

On the other hand, the limestone 50 is included in the first organic packed layer 12 located on the most upstream side of the discharge path (W) of the acid mine drainage (A) of the organic layer (10). This limestone is for neutralizing the acid mine drainage (A) flowing into the first organic packed layer 12. In particular, when the pH of the acid mine drainage (A) is 3.5 or less, since the metabolism of the sulfate reducing bacterium supported on the organic material layer 10 is not actively performed, neutralization at the initial stage when the acid mine drainage (A) is introduced To increase the pH.

In order to determine the effect of the sulphate sulfate reduction facility according to the second embodiment of the present invention having the above configuration, in the second embodiment of the present invention as shown in Figure 10, the first, second, third, fourth Experiments were carried out on the organic packed layers (12, 13, 14, 15) and the limestone layer (80) with a height of 12 cm (H), a width of 12 cm (D), and a length of 30 cm (F). Was performed. Compared with Model 1, a fourth organic packed layer 15 was further installed, and limestone pieces 50 were added to the first organic packed layer 12, and the other experimental conditions were the same. 11 to 14 are shown so that the data obtained from the model 3 and the experimental data obtained from the model 1 are compared with each other.

FIG. 11 shows the change in pH over time (date) of acid mine drainage (A) discharged from Model 1 and Model 3 to determine the neutralization efficiency.

FIG. 12 relates to the loading efficiency of iron, and shows the change over time of the removal rate of iron in the acid mine drainage (A) discharged from Model 1 and Model 3, and FIG. 13 shows precipitation of aluminum. Regarding the efficiency, the change over time (date) of the removal rate of aluminum in the acid mine drainage (A) discharged from Model 1 and Model 3 is shown, Figure 14 relates to the removal rate of sulfate, Model 1 And the change over time (date) of the removal rate of sulfate in acid mine drainage (A) discharged from Model 3 is shown.

 Referring to FIG. 11, it can be seen that the pH of the acid mine drainage (A) is significantly higher in Model 3 than in Model 1, which is limestone added to the first organic packed layer 12 to enhance neutralization. Is the result. As shown in Figs. 12 and 13, the removal rate of iron and aluminum is better than 90% in both Model 1 and Model 3. Referring to FIG. 14, the sulfate removal rate is shown to be much superior to model 3 as compared to model 1. This is the result of sulphate reducing bacteria actively performing sulphate reduction through metabolic action by adding limestone to the first organic packed layer 12 to neutralize the acid mine drainage (A) at the beginning of its inflow to raise the pH. . As shown in the above experimental data, the natural purification chamber of the acid mine drainage according to the second embodiment of the present invention is very efficient in raising the pH and removing the sulfate.

Meanwhile, in the embodiments of the present invention, as shown in FIG. 15, the limestone layer 80 passes through the limestone layer 80 on the discharge path W of the acid mine drainage A. It may be further provided with a sedimentation tank 90 in the form of a pond in which the acid mine drainage (A) discharged temporarily. The sedimentation tank 90 is for depositing residual solids such as heavy metals or organic matters by their own weight in the acid mine drainage A discharged through the organic layer 10 and the limestone layer 80, and the abandoned mine (M). It can be installed outside the tunnel (P). The size of the settling tank 90 preferably has a size that the acid mine drainage (A) can stay 20 hours to 28 hours in the settling tank (90). If the residence time of the acid mine drainage (A) is less than 20 hours, it is difficult because the remaining solids are insufficient to precipitate, and if the residence time is more than 28 hours, the excessively long time without increasing the precipitation efficiency. By staying in the settling tank 90, there is a problem that the size of the settling tank 90 should be increased more than necessary. Accordingly, the size of the settling tank 90 may be set in consideration of the flow rate and flow rate of the acid mine drainage (A).

As described above, in the mine shaft sulfate reduction facility according to the present invention is disposed in the tunnel where the temperature is maintained in a certain range irrespective of the change of the season, the metabolic action of the sulfate reducing bacterium can be performed smoothly at this temperature range. Therefore, the purification efficiency of acid mine drainage can be kept constant, which can solve the problem of the acid mine drainage purification process in winter when the temperature drops sharply, and solve the problem of lack of site for installation of natural purification facilities. .

Claims (9)

It is disposed on the discharge path of acid mine drainage, which is discharged from the abandoned mine and contains a large amount of heavy metal and sulfate ions, to neutralize the acid mine drainage and to precipitate heavy metal contained therein. An organic material layer filled with an organic material composed of CH ₂ O, Sulfate supported on the organic substance, the organic substance is an electron donor and the sulfate ion contained in the acid mine drainage is used as an electron acceptor to reduce the sulfate ion and generate alkalinity to neutralize the acid mine drainage. In the mine sulphate reduction facility containing reducing bacteria, In order to maintain a constant temperature of the organic material layer carrying the sulfate reducing bacteria, the organic material layer is in the mine shaft reducing facility, characterized in that installed in the tunnel of the abandoned mine. The method of claim 1, The organic material layer is composed of a plurality of organic material packed layers arranged in sequence along the discharge path of the acid mine drainage, Partition walls are respectively provided between the organic packing layers so that the plurality of organic packing layers sequentially arranged are separated from each other. Characterized in that the discharge hole passing through the partition wall is formed alternately in the upper and lower portions along the plurality of partition walls arranged in sequence so that the discharge path of the acid mine drainage passing through the plurality of organic material packed bed is a wave shape. Sulfuric acid sulfate reduction facility. The method of claim 2, To neutralize the acid mine drainage flowing into the plurality of organic material layers, In the pit sulfate reduction facility, characterized in that limestone is included in the organic packing layer located on the most upstream side of the discharge path of the acid mine drainage among the plurality of organic packing layers. The method of claim 1, In the organic material layer, the shaft sulfate reduction facility, characterized in that the gravel layer is further provided on the lower portion of the organic material. The method of claim 1, Sulfate reduction facility in the shaft, characterized in that the observation hole penetrating further between the surface of the abandoned mine and the organic layer. The method of claim 1, In order to reinforce the neutralization treatment of the acid mine drainage, the limestone layer in which the limestone is filled downstream of the organic material layer on the discharge path of the acid mine drainage is further provided. The method of claim 1, In order to precipitate heavy metals present in the acid mine drainage, a precipitation tank for temporarily receiving the acid mine drainage is further provided outside the tunnel of the abandoned mine on the discharge side of the acid mine drainage. In-gang sulfate reduction facility. The method of claim 7, wherein The sedimentation tank is a sulphate reduction facility in the ganglia, characterized in that the acid mine drainage is made to be 20 to 28 hours in consideration of the flow rate of the acid mine drainage discharged through the organic material layer. The method of claim 1, The organic matter is a mushroom compost, a mixture of rice straw and manure, sawdust, oak compost, oak bark, pine needles, sewage sludge, paper sludge, dairy residues, characterized in that consisting of at least one residue.

Images