KR100916842B1 - Improved alkali supplying tub for purifing acid mine drainage and constructring method thereof - Google Patents

Abstract

An improved alkali supply vessel for purifying acid mine drainage and a method for constructing the same are provided to process a large amount of mine water, and the mine water of high acidity, and to offer easy maintenance and repair property of the vessel. An improved alkali supply vessel for purifying acid mine drainage includes a stirring layer(10), a substrate material layer(20), and a perforated layer(30). The stirring layer removes iron with sulfate-reducing bacteria, and to supply alkalinity to neutralize the mine water. The substrate material layer prevent precipitation of iron oxides. The perforated layer is installed between the stirring layer and the substrate material layer. The alkali supply vessel further includes a carbon source supply part(40), a plurality of detection parts(50), a guide pipe(60), and a filtration net(70).

Description

IMPROVED ALKALI SUPPLYING TUB FOR PURIFING ACID MINE DRAINAGE AND CONSTRUCTRING METHOD THEREOF}

The present invention relates to an improved alkali supply tank for acid mine drainage purification and a construction method thereof, and more specifically, a mine having a high acidity in general as the pH is low and the concentration of sulfate and iron, aluminum, etc. is high. The present invention relates to an improved alkali supply tank for acid mine drainage purification and its construction method for treatment by maximizing the activity of sulfate reduction bacteria by adjusting the pH of acid drainage in the pit to near neutral.

In general, the conventional techniques for treating acid drainage in mine pit are divided into two types: physical and chemical treatment techniques and natural purification treatment techniques. First, the physical and chemical treatment technology is mainly used to treat large-scale mines and mines with high acidity and heavy pollution such as iron, which dissolves hydrated lime and sodium hydroxide in the mines, causing flocculation and sedimentation reactions to be contained in the mines. As a technology for processing heavy metals such as contaminated iron, there are disadvantages in that it takes a lot of costs from initial construction to subsequent maintenance such as initial facility cost, drug purchase cost, and manpower cost. Secondly, the natural purification treatment technology was developed to be applied as a low cost treatment technology considering the cost of physical and chemical treatment technology. Oxidative precipitation tanks, marshes, and Successive Alkalinity Producing System (SAPS) are commonly used for this purpose. .

Among the above water treatment technologies, the natural purification treatment technology installs pond-like ponds such as oxidative precipitates and marshes to precipitate oxidized precipitates in the case of pH higher than neutral or high alkalinity, so that the pit water stays in this space for a long time. On the other hand, natural purification treatment technology for the treatment of low pH and high acidity water has been studied to apply the method using microorganism and limestone. One example is SAPS, as shown in FIG. 1, a limestone layer is laid at a lower portion of about 1m, and a substrate material (compost, etc.) is laid at a height of 15 to 50 cm thereon, and then the mine water flows from the top to the bottom. By taking this, the mine water is treated by reaction with bacteria in the substrate material layer and alkalinity supply by dissolution of the limestone layer. The reason for laying the substrate material is that by removing the dissolved oxygen in the mine water, the lower limestone layer can be made anaerobic condition so that the dissolution of the limestone can be maintained to supply alkalinity. Although SAPS shows a high effect in some mine waters, the supply of alkalinity using only limestone is not only limited to the treatment of acid acid mine water with high acidity, but also requires a large land area, which is economical advantage over physical and chemical treatment. The incidence of the problem is difficult. In addition, when the aluminum concentration is high, aluminum may be coated and adsorbed on the limestone layer, so that the dissolution rate of the limestone may be lowered.

The improved RAPS (Reducing & Alkalinity Producing System) reactor to overcome the above disadvantages of SAPS is applied by stirring the compost layer and the limestone layer as shown in FIG. 2, but the limestone and the compost are agitated on the whole layer to the limestone. Due to the expanded voids, the depth of the upper layer is required to make anaerobic conditions deeper than SAPS, and as the iron precipitate is generated by the rise of the pH by limestone at the top, the overall permeability is lowered, and the maintenance cost for the removal is reduced. There are many problems compared to the SAPS group.

The present invention has been made to solve the above-mentioned problems of the prior art, by adjusting the pH of the water in the vicinity of the neutral to improve the activity of the sulfate reduction bacteria to improve the acidic mines that can optimally treat the high acidity of the mine water An object of the present invention is to provide an alkali supply tank for drainage purification and a construction method thereof.

It also improves acid mine drainage purification by preventing iron oxide deposits from accumulating inside the reactor, facilitating maintenance, enabling high acidity gangly water treatment, and ensuring excellent permeability to allow large-scale gangly water treatment. Its purpose is to provide an alkali feeder and its construction method.

In addition, it is an object of the present invention to provide an improved alkali supply tank for acid mine drainage purification and its construction method which facilitates the exchange of the upper substrate material layer during maintenance and refurbishment.

In order to achieve the above object, the present invention, the stirring is not only to supply the alkalinity to neutralize the acid mine drainage as the agitated mixture of the alkali feeder and the substrate material is disposed, it is possible to remove the iron by sulfate reducing bacteria A layer; It is installed 5 to 10cm high on the stirring layer to remove the dissolved oxygen of the incoming acid mine drainage to meet the anaerobic conditions to easily react with the acid mine drainage and to prevent iron oxide from being precipitated at the same time. Substrate material layer for; characterized in that consisting of.

Wherein the alkali supply is made of one or more of limestone, oyster shell, crab shell, steelmaking slag, the substrate material is made of one or more of compost, sawdust, crest, chicken dung, cow dung, wood chips, the stirring layer and the substrate Between the material layer is characterized in that the perforated plate is installed to prevent the stirring layer and the substrate material layer is mutually disturbed and to facilitate the replacement of the substrate material layer.

In addition, a carbon source supply unit for additionally providing a liquid carbon source to increase the heavy metal removal rate by the sulfate reducing bacteria is further included, the stirring layer and the substrate material layer a plurality of sensing for measuring the dissolved oxygen concentration along the vertical direction It is characterized in that the additional installation.

In addition, a guide pipe having a plurality of through holes is installed below the stirring layer to guide the introduced water to a predetermined path, and the stirring material of the stirring layer is introduced into the guide pipe between the stirring layer and the guide pipe. It is characterized in that the filtering net is further installed to prevent.

On the other hand, the present invention comprises the steps of installing a guide pipe having a plurality of through-holes to guide the water introduced into the predetermined path; Installing a filtering network on an upper side of the guide pipe to prevent foreign substances from entering into the guide pipe; Placing an agitated mixture of an alkali feeder and a substrate material on the upper side of the filter network to supply alkalinity to neutralize acid mine drainage, and to form a stirring layer to remove iron by sulfate reducing bacteria; Installing a perforated plate above the stirring layer; The substrate is installed on the perforated plate at a height of 5 to 10 cm to remove dissolved oxygen of the introduced acid mine drainage so as to satisfy the anaerobic conditions so that the stirred layer reacts easily with the acid mine drainage and prevent iron oxide from being precipitated. Forming a material layer; characterized in that consisting of.

As described above, the improved alkali supply tank for acid mine drainage purification and the construction method thereof according to the present invention form the substrate material layer of low height over the stirring layer where the alkali feeder and the substrate material are stirred, thereby forming a shaft through the stirring layer. The pH of the acid mine drainage is adjusted to near neutral to maximize the activity of the sulfate-reducing bacterium, and to satisfy the anaerobic conditions of the stirred layer through the substrate material layer to optimally treat the high acidity mine water.

In addition, since the dissolved oxygen of the acid mine drainage can be removed through the substrate material layer to prevent the iron oxide precipitates from accumulating in the reaction tank, the time required for the maintenance of the reaction tank is thus extended, and the stirring material and Acidic acid drainage shows a neutral pH from the beginning of the reaction, allowing iron removal by sulfate reduction bacteria in addition to alkalinity, enabling high acidity ganglion water treatment and improved water permeability between the substrate material layer and the stirring layer. It can secure a large amount of mine water.

In addition, by installing a perforated plate between the stirring layer and the substrate material layer, it is possible to facilitate the exchange of the substrate material layer during the maintenance and repair of the reactor.

Hereinafter, with reference to the drawings will be described an improved alkali supply tank for acid mine drainage purification (hereinafter referred to as MAPS (MIRECO Alkalinity Producing System) tank) and its construction method according to the present invention.

3 is a cross-sectional view showing an improved alkali supply tank for acid mine drainage purification according to the present invention.

The improved alkali supply tank for acid mine drainage purification according to the present invention basically comprises a stirring layer 10 in which an alkali supplier and a substrate material are stirred, and a substrate material layer 20 formed on the stirring layer 10.

The stirring layer 10 is formed of an agitated mixture of an alkali feeder and a substrate material, which not only neutralizes acid mine drainage introduced into the feeder but also removes iron by a sulfate reducing bacterium. As the alkali feeder, limestone, oyster shell, crab shell, steel slag, etc. may be used alone or in combination. As the substrate material, compost, sawdust, crest, chicken dung, cow dung, wood chips, etc. may be used alone or in combination. . On the other hand, when looking at the chemical reaction of the sulfate reduction bacteria organic matter contained in the substrate material and composed of CH ₂ O, SO ₄ ^2- and sulfate reduction bacteria contained in a large amount of acid mine drainage reacts H ₂ S and 2HCO ₃ ^- is reduced to hydrogen sulfide is a reduced back 2 is removed in the form of sulfide minerals in combination with the metal (M). The chemical formula for this is as follows.

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

H ₂ S + M ²⁺ → MS _(s) + 2H ⁺

Next, the reaction treatment according to the increase in alkalinity of the alkali feeder is CaCO ₃ , CO ₂ and H ₂ O reacted to form Ca ²⁺ and 2HCO ₃ ⁻ as shown in the following formula, and Fe ²⁺ contained in the acid mine drainage is HCO Reacts with ₃ ^- and is subsequently removed with iron hydroxide.

_{CaCO 3 + CO 2 + H 2} O → Ca 2+ + 2HCO 3 -

_{^{Fe 2+ + HCO 3 - → FeCO}} 3 + H +

Fe ²⁺ + 3H ₂ O → Fe (OH) ₂ + 2H ⁺

Fe ³⁺ + 3H ₂ O → Fe (OH) ₃ + 3H ⁺

The substrate material layer 20 is preferably placed on the stirring layer 10 to a height of 5 ~ 10cm, to remove the dissolved oxygen of the acid mine drainage flows to facilitate the stirring layer 10 reacts with the acid mine drainage. In order to meet the anaerobic conditions and to prevent the precipitation of iron oxide in the alkali feed tank (or reaction tank) is formed by depositing one or more of the substrate materials as described above.

Hereinafter, an embodiment of an improved alkali supply tank for acid mine drainage purification according to the present invention will be described.

4 is a graph showing the pH of raw water and effluent passed through each reactor, and FIG. 5 is a graph showing iron concentrations of raw water and effluent passed through each reactor.

In the embodiment of the present invention, the pH of the water, raw water in the mine containing 250 mg / L and 30 mg / L of iron, the flow rate of 3m ³ / day SAPS, RAPS, MAPS bath using the same amount of substrate material and limestone Pilot experiments were performed by adding to each. Table 1 shows the components of the effluent treated through each reaction tank, Figures 4 and 5 show the pH and iron concentrations of the raw water and the effluent through each reaction tank, the analysis point is the raw water and SAPS, RAPS, MAPS bath It is a place to collect the final discharged water after going through.

Table 1- Comparison of raw water and composition of SAPS, RAPS, MAPS tank effluent

enemy SAPS RAPS MAPS pH 3.5 3.6 5.3 6.3 Fe (mg / L) 250 30 20 0.9 Al (mg / L) 30 One 0.8 0.6 Alkalinity (mg / L CaCO ₃ ) 0 0 15 60

As shown in Table 1 and Figures 4 and 5, it can be seen that the improved alkali supply tank for acid mine drainage purification according to the present invention shows the best performance for acid mine drainage treatment.

On the other hand, as the stirring layer 10 and the substrate material layer 20 are sequentially stacked, each layer may be disturbed with each other, so that the perforated plate 30 made of plastic is installed to prevent this, and the perforated plate In addition to the effects as described above, the performance of the substrate material layer 20 over time since the stirring layer 10 and the substrate material layer 20 can be clearly distinguished by the perforated plate 30. This can provide ease of operation even when it is necessary to replace it due to degradation.

In addition, in order to maximize the effect of the sulfate reduction bacteria as described above, in the case where the carbon source provided by the substrate material is insufficient, a liquid carbon source, such as alcohol, separately through the carbon source supply unit 40 to the part where the MAPS tank receives acid mine drainage. You can also place it. The carbon source supply unit 40 normally stores the carbon source in the inner space, and when it is determined that the carbon source in the substrate material is insufficient, opens the valve and injects it into the MAPS tank. Mixing with drainage is not overwhelming.

In addition, by installing a plurality of sensing units 50 for measuring dissolved oxygen along the vertical direction in the stirring layer 10 and the substrate material layer 20, it is possible to confirm whether the MAPS tank is generally functionally abnormal. The sensing unit 50 is made of a sensor for measuring the oxygen concentration in a conventional liquid phase and the measured data value can be confirmed by being transmitted to the terminal in a wired or wireless manner. The reason why the plurality of sensing units 50 are installed in the vertical direction is to check and maintain the replacement cycle of the substrate material or the position of the parts to be replaced by measuring the oxygen concentration state for each level at which the sensing unit 50 is installed. In addition, it is to minimize the height of the substrate material layer 20 when forming. By simply limiting the measurable data in the sensing unit 50 to the dissolved oxygen concentration, the overall performance of the MAPS tank can be confirmed, but the concentration of sulfate reduction bacteria and the concentration of heavy metals can be measured directly or indirectly to provide a more clear MAPS. Joe's monitoring can be done.

In the existing SAPS or RAPS, the drain pipe is used at the end of the reactor to discharge the final discharged water, but in the MAPS tank of the present invention, a plurality of through holes are introduced to guide the purified water through the stirring bed 10 to a predetermined path. As the guide pipe 60 having the bottom is further provided under the stirring bed 10, it is possible to minimize the absorption of the discharged water in the reaction tank of the uppermost layer to the basement position of the reactor in the MAPS tank having the stepped shape. have. Here, by installing a separate filter net 70 between the guide pipe 60 and the stirring layer 10, it is possible to prevent the stirring material of the stirring layer 10 through the through hole of the guide pipe 60 to be drawn in, The filter net 70 may be made of a material having fine pores such as fabrics, and the gap gap thereof includes water containing agitated material having a predetermined particle size introduced into the guide pipe 60 through the filter net 70. It may be enough to be discharged to the outside of the guide pipe 60 by the hydraulic pressure.

The improved construction method of the acid mine drainage purification alkali supply tank according to the present invention comprises the steps of installing a guide pipe 60 having a plurality of through holes to guide the water introduced into the predetermined path, and the guide pipe 60 ) Neutralizing the acid mine drainage by installing a filtration net 70 on the upper side of the filtration net 70 to prevent the introduction of foreign substances into the inside of the filtration medium, and placing an agitated mixture of the alkali feeder and the substrate material on the upper side of the filtration net 70. Forming a stirring layer 10 so as to not only supply the alkalinity for the iron removal by the sulfate reducing bacteria, and to install the perforated plate 30 above the stirred layer 10, and the perforated plate 30 Installed at a height of 5 to 10 cm above, by removing the dissolved oxygen of the acid mine drainage flows into the anaerobic tank so that the stirring layer 10 reacts easily with the acid mine drainage. Forming the substrate material layer 20 so as to satisfy the gun and prevent the iron oxide from being precipitated, and the sensing unit 50 in the step of forming the stirring layer 10 and the substrate material layer 20 ) May include installing a sensor 50 as described above for measuring the concentration of dissolved oxygen, sulfate reduction bacteria, heavy metals, and the like.

1 is a cross-sectional view showing a SAPS tank according to the prior art.

Figure 2 is a cross-sectional view showing a RAPS tank according to the prior art.

Figure 3 is a cross-sectional view showing an improved alkali supply tank for acid mine drainage purification according to the present invention.

Figure 4 is a graph measuring the pH of the raw water and the effluent through each reactor.

5 is a graph showing the iron concentration of raw water and effluent water passed through each reactor.

Claims (9)

delete delete delete A stirring layer 10 for supplying alkalinity for neutralizing acid mine drainage as well as for stirring the alkali feeder and the substrate material, and for removing iron by sulfate reducing bacteria; It is installed on the stirring layer 10, by removing the dissolved oxygen of the acid mine drainage flows to prevent the iron oxide is precipitated at the same time to meet the anaerobic conditions to easily react with the acid mine drainage. Consists of a substrate material layer 20 for The perforated plate between the stirring layer 10 and the substrate material layer 20 prevents the stirring layer 10 and the substrate material layer 20 from being mutually disturbed and facilitates the replacement of the substrate material layer 20. 30) is an improved alkaline supply tank for acid mine drainage purification, characterized in that the installation. The method according to claim 4, Improved acid mine drainage purification alkaline supply tank further comprises a carbon source supply unit 40 for additionally providing a liquid carbon source to increase the heavy metal removal rate by the sulfate reducing bacteria. The method according to claim 5, Improved acid mine drainage purification alkali supply tank, characterized in that the stirring layer (10) and the substrate material layer (20) is provided with a plurality of detection unit (50) for measuring the dissolved oxygen concentration along the vertical direction. The method according to any one of claims 4 to 6, Improved acid mine drainage purification alkali supply tank, characterized in that the guide pipe 60 having a plurality of through-holes are installed in the lower side of the stirring layer 10 to guide the introduced water in a predetermined path. The method according to claim 7, Improvement between the stirring layer 10 and the guide pipe 60, characterized in that the filtering net 70 for preventing the stirring of the stirring layer 10 is introduced into the guide pipe 60 is further improved Supply tank for purified acid mine drainage. In the method for constructing an improved alkali supply tank for acid mine drainage purification according to claim 8, Installing a guide pipe (60) having a plurality of through holes to guide the water introduced into the predetermined path; Installing a filtering network (70) on an upper side of the guide pipe (60) to prevent foreign substances from entering into the guide pipe (60); The stirring layer 10 is formed above the filter network 70 to provide an alkalinity to neutralize the acid mine drainage by arranging an agitated mixture of an alkali supply material and a substrate material, and to form an agitation layer 10 to remove iron by sulfate reducing bacteria. Making a step; Installing the perforated plate (30) above the stirring layer (10); By installing 5 to 10 cm high on the perforated plate 30, by removing the dissolved oxygen of the acid mine drainage flows to meet the anaerobic conditions so that the stirring layer 10 easily reacts with the acid mine drainage and iron oxide Forming a substrate material layer (20) to prevent the precipitation; Construction method of the improved acid supply tank for purification of acid mine drainage, characterized in that consisting of.

Images