KR20160102361A - Method of Hybridly Treating Acid Mine Drainage with Clay Minerals and Microalgae - Google Patents

Abstract

The present invention relates to a method for mine drainage treatment. According to the present invention, a strongly acidic element of mine drainage is neutralized first so that the mine drainage discharged in an abandoned mine or an idle mine can be efficiently treated. The purpose of the neutralization is to utilize microalgae to a larger extent with selection of the microalgae capable of performing a photobiological reaction in a strongly acidic solution being difficult. Once the mine drainage is primarily neutralized, a heavy metal present in the mine drainage is secondarily and biologically removed and biomass is obtained at the same time. The hybrid mine drainage treatment method according to the present invention is provided in this manner.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for treating an acidic mine drainage using a clay mineral and microalgae,

The present invention relates to a method for treating acid mine drainage using clay minerals and microalgae, and more particularly, to a method for neutralizing acid mine drainage discharged from abandoned mines or mines, using clay minerals harmless to the human body, The present invention relates to a method for treating acid mine drainage which proceeds in a hybrid manner by efficiently removing heavy metals present in mine drainage by microalgae and simultaneously obtaining biomass.

In Korea, the development of mines has been active in order to expand the energy demand due to the modernization of the 60s and 70s in the past. However, since the mid 1980s, the consumption pattern of energy has changed and since the 1989 rationalization project of the coal industry, Is abandoned.

Environmental pollution in these abandoned mines is a subject that is frequently being addressed. Environmental pollution problems from abandoned mines arise mainly from mine waste rock, tailing and acid mine drainage (AMD) associated with them.

AMD in the abandoned mine area refers to low-effluent water generated by the oxidation of sulfide and iron (Fe) in the wastewater and mine wastes. This is because pyrite (FeS ₂ ) and petroleum (FeS) Are formed by reacting with water and oxygen under aerobic conditions. It is known that hydrogen ions are generated during the reaction to produce AMD having a low pH value.

AMD in abandoned mines contains heavy metal ions such as aluminum, cations such as aluminum, iron, manganese, cadmium, arsenic, and high concentrations of sulphate, and because the pH is very low, these AMD contaminate the soil and groundwater in nearby areas Crops will be adversely affected. In addition, AMD flows into rivers and forms reddish brown deposits on the bottom of the stream, which has a negative impact on the ecological environment.

Today, AMD's processing methods can be roughly classified into two categories: first, preventing AMD formation; and second, inhibiting the activity of microorganisms.

The AMD formation prevention method is a method of preventing the formation of AMD by blocking the supply of oxygen to a specific region. This method is intended to prevent the oxidation of pyrite by oxygen by putting synthetic materials on the soil of abandoned mines or abandoned mines, or by blocking the supply of oxygen by blocking the mines of abandoned mines. However, such a method has a problem in that it is impossible to shut off a perfect oxygen supply, and thus the groundwater contamination area can be further diffused.

The method of inhibiting activity of the microorganisms is a method of inhibiting the oxidation of pyrite by sterilizing a microorganism (for example, Thiobacillus ferrooxidans) which determines the oxidation rate of pyrite. In order to sterilize the oxidizing microorganism of the pyrite, an additional microorganism sterilant should be administered. As such sterilant, sodium lauryl sulfate or sodium benzoate is mainly used. In West Virginia and Dawmont in the United States, this method was used to reduce the leakage of AMD. However, this method is not suitable for the acidification of mine drainage due to the fact that the sterilizing agent may cause further water pollution, maintain the continuous application of the sterilant, and the effective sterilant supply depends on the structural and hydraulic geology characteristics. There is a problem with the method of preventing.

On the other hand, since abandoned mines in Korea are mainly concentrated in mountainous areas, especially in Gangwon area, there is a problem that it is difficult to secure a site for a natural purification facility for AMD having a very high pollution load, And management of mine waste and the establishment and operation of facilities that can prevent pollution from mining areas are being neglected.

Although this problem is not limited to Gangwon area but it is a common phenomenon in the area where abandoned mines exist, there are very few researches and techniques to solve such problems.

Korean Patent No. 10-527336 "Method for Purifying and Purifying Acid Mine Drainage Using Sulfate Reducing Bacteria" (2005. 11. 2); Korean Patent No. 10-427774 "Method and apparatus for purifying abandoned mine drainage" (2004. 4. 7.); Korean Patent No. 10-667095 "Mine drainage treatment apparatus and mine drainage treatment method using same" (2007. 4. 4.); Korean Patent No. 10-649729 "Purification apparatus and purification method of acid wastewater" (Nov. 17, 2006); Korean Utility Model Registration No. 20-357173 "High Concentration Transfer Device for Acid Wastewater" (2004. 14. 14).

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for treating acidic mine drainage discharged from abandoned mines or mines by physically neutralizing them using a clay mineral adsorbent harmless to the human body, It is an object of the present invention to provide a method for treating acid mine drainage which proceeds in a hybrid manner by biologically removing heavy metals present in the secondary neutralized mine drainage and simultaneously obtaining biomass.

In order to accomplish the above object, the present invention provides a method of treating a mine drainage wastewater, comprising: a pre-treatment step of collecting acidic mine wastewater discharged from abandoned mines or fugitive mines, removing suspended matters and contaminants from the mines; Neutralizing the mineral wastewater by adding the clay mineral neutralization adsorbent to the pre-treated mineral wastewater at a ratio of 10: 1 to 10: 3 and kneading the mineral wastewater for 1 hour to 5 hours to neutralize the mineral wastewater; The selected microalgae are cultivated at a constant temperature and culture conditions and grown for 7 days to 12 days. The neutralized mine drainage and the culture of the microalgae are then mixed at a ratio of 10: 0.5-3 volume (v / v) and kneaded for 1 day to 6 days at room temperature while supplying air from the outside. In the course of the mixing, the micro-algae for drinking water feeds the nutrients in the mine drainage to the mine drainage A photobiological treatment step with microalgae removing heavy metal contaminants; A finishing treatment step of discharging the treated water through the biological treatment step with the microalgae and separately obtaining microalgae grown by absorbing heavy metal contaminants in the previous stage; .

The present invention primarily neutralizes acid mine drainage using clay minerals and then removes contaminants from mine drainage using microalgae, thereby effectively removing the final heavy metal material.

In addition, since the present invention treats AMD with clay minerals and microalgae, there is an advantage of being environmentally friendly and economical because no chemicals are used as in the prior art.

Further, since the present invention can use a simple device, it is advantageous in that it can be easily applied even to a small-scale mine company with a narrow space.

Further, since the present invention can remove heavy metals in mineral wastewater and additionally obtain biomass due to microalgae, it can be used for other purposes such as biodiesel using biomass, and thus it is an allotment.

1 is a schematic block diagram of a method for treating mine drainage according to the present invention,
2 is a conceptual diagram of a treatment apparatus suitable for carrying out a method of treating mine drainage according to the present invention,
3 is a graph showing the neutralization process of mine drainage by time zone,
4 is a graph showing the removal rate of heavy metal contaminants after the entire process of the present invention,
Figure 5 is a chart showing the amount of biomass obtained after the entire process of the invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be understood, however, that the drawings are for the purpose of describing the technical idea of the present invention in more detail and that the technical idea of the present invention is not limited thereto and that various modifications are possible. In the specification of the present invention, the same reference numerals are used for the same parts, and parts that can be easily created by those having ordinary skill in the art are omitted in the description of the present invention. .

In the present invention, the term "mine drainage" means drainage water or mine waste water flowing out from abandoned mines or mines. The mine drainage is usually acidic due to oxidation of sulfide and iron derived from waste wastes or mine waste and includes heavy metal ions such as aluminum, iron, manganese, cadmium and arsenic .

1 is a schematic block diagram of a method for treating mine drainage according to the present invention,

2 is a conceptual diagram of a treatment apparatus suitable for carrying out a method of treating mine drainage according to the present invention.

The present invention includes a pretreatment step (S 210) for removing suspended matters and contaminants from mine drainage.

The preprocessing step (S 210) collects the mine drainage generated in the mine or abandoned mine, and removes impurities such as float, soil, and fine dirt from them. The manner of removing the suspended matters and the contaminants in the mine drainage can be carried out by conventional methods and conventional means.

In the pre-treatment step (S 210), if the floating matters and the contaminants are removed in the mine drainage, it is preferable that the pre-treatment step (S 210) is put into a predetermined storage vessel and allowed to stand for a predetermined period. The waste water is supplied to the storage vessel to stabilize the pre-treated mine drainage, and to smoothly proceed to the next step. The storage vessel includes a commonly used flow rate regulator, and the screening operation may be performed thereafter or simultaneously.

The present invention includes a neutralization treatment step (S 220) of neutralizing the pre-treated mineral wastewater by neutralizing the clay mineral with the neutralizing adsorbent.

The present invention proceeds to the neutralization treatment step (S 210) of the mine drainage in two steps. First, a clay mineral neutralization adsorbent is prepared to neutralize the pre-treated mineral wastewater, and then the neutralization process is performed by injecting the clay mineral neutralization adsorbent into the mine drainage.

In order to neutralize mine wastewater, the present invention uses clay minerals having adsorption performance and appropriately processes the clay minerals to prepare neutralized adsorbents.

The clay mineral neutralization adsorbent may be selected from the group consisting of bentonite, carolin (kaolinite), dolomite, loess, quartzite, and sericite. The reason for using the clay mineral neutralization adsorbent in the present invention is that when the mine drainage has a strong acidity, it can survive in a strong acidic solution when proceeding with a photobioreaction, and at the same time, The present invention is intended to enable the photobioreaction to be carried out by using the micro-algae containing the common water by neutralizing the mine drainage, since there is a certain limit to the kinds of algae. In other words, by converting the strong acid mine drainage to the neutralized mine drainage, the photobioreaction can be carried out under much more favorable conditions by using the micro-algae.

Preferably, the clay mineral neutralization adsorbent is finely pulverized and used, or calcined sericite is calcined. The clay mineral neutralizing adsorbent has been mainly used in the field of ceramics due to its high plasticity, drying strength and green strength. In addition, it has been widely used in various fields such as paints, electric insulators, Have been used. The clay mineral neutralization adsorbent is finely pulverized and used. By finely grinding, the surface area can be further expanded. The finely pulverized clay mineral neutralization adsorbent is separated using a sieve vibrator and collected at a size of approximately 300 to 600 mesh.

The clay mineral neutralization adsorbent can be used in powder form, but it is more preferable to use it by activating by calcining at a high temperature. When used in powder form, it is more preferable to mix it with a predetermined binder component and make it into a predetermined immobilized shape since it is disturbed in the wastewater. The predetermined fixed shape is not particularly limited, but a dongle dongle shape is preferable. As a method of activation, it can be carried out in a manner that it is primarily mixed with a predetermined binder and is fixed in a fixed form, and thereafter, the immobilized sericite complex is secondarily fired at a high temperature and then cooled.

In order to produce the clay mineral neutralization adsorbent, 80% by weight to 90% by weight of the particulate clay mineral and 10% to 20% by weight of the binder component are uniformly mixed and then water is added and fixed in a predetermined shape. When the amount of the particulate clay mineral is less than 80 wt%, the neutralizing adsorbent component is relatively undesirable because the component is relatively small. When the particulate clay mineral is more than 90 wt%, the binding force of the binder component is weak, Is likely to be broken, which is not preferable.

The binder component allows the particulate clay mineral to be retained and retain its shape under high temperature calcination temperature conditions, thereby preserving the shape of the final neutralized adsorbent. As such a binder component, lime is most preferable, and titanium dioxide (TiO ₂ ) or magnesia (MgO) can be used together or separately. The fine clay minerals and the binder component are kneaded and then molded at a high pressure in a certain mold. The molded body is preferably a dongle-shaped body.

The clay mineral compact having the form of a dongle dongle is put into a high-temperature firing furnace, and then heat-treated at a temperature of 600 ° C to 700 ° C for a period of about 1 hour to 2 hours, and then heated again at a high temperature of 1100 ° C to 1200 ° C for 10 minutes to 20 minutes High temperature calcination treatment activates the clay mineral. This is because the heat treatment is first performed at a relatively low temperature in the high-temperature firing furnace, and then the high-temperature firing process is performed at a relatively high secondarily, thereby avoiding a sudden thermal shock to the clay mineral- So that the shape of the mineral compact can be maintained and at the same time the structure of the clay mineral can be effectively deformed.

Since the clay mineral usually has a very dense layered structure, it is presumed that the dense layered structure gradually deforms through the first and second heating processes, and forms a disordered and non-uniform non-layered structure Loses. In addition, in the case of conventional clay minerals, it has very small pores. When calcined at a high temperature, it is considered that the small pores are deformed into an expanded form or a large number of pores are newly formed. The firing time at the high temperature may vary depending on the temperature range, but generally requires a relatively long time at low temperature firing, while a relatively short time is required at high temperature firing.

When the activation work of the clay mineral is terminated in the high-temperature firing furnace, it is cooled and obtained as a clay mineral neutralization adsorbent at room temperature.

In the present invention, the clay mineral neutralization adsorbent is introduced into the above-mentioned pretreatment mine drainage, and the mine drainage: the clay mineral neutralization adsorbent is added at a ratio of 10: 1 to 10: 3, and the mixture is kneaded for 1 hour to 5 hours, Lt; / RTI > The input ratio is preferably based on volume. When the clay mineral neutralization adsorbent is added to the mineral wastewater at a ratio of 10: 1 or less, it takes a long time to neutralize the mineral wastewater, and it is difficult to obtain an adequate level of neutralization effect. On the other hand, when the clay mineral neutralization adsorbent is added to the mineral wastewater at a ratio of 10: 3 or more, it is possible to neutralize the clay mineral wastewater in a relatively short time, but it is not economically preferable due to excessive neutralization of the adsorbent.

When the clay mineral neutralization adsorbent is added to the mineral wastewater and continuously kneaded, the ionic substances present in the mineral wastewater are partially adsorbed on the clay mineral neutralization adsorbent, and the alkali components of the clay mineral neutralization adsorbent They tend to be neutralized. More specifically, it is as follows.

In general, clay minerals are hydrated aluminum silicate minerals that make potassium the primary cation. The basic crystal structure consists of three layers including smectite, two tetrahedral layers and one octahedron layer, and there are K ⁺ and OH ^- , Fe and Mg between the layers. For example, clay minerals alone have weak alkalis (pH 8 to 9), and the fine particles have a slightly higher pH. This is because the ion substitution ability acts proportionally to the particle surface area.

When clay minerals having such a substitution ability meet with AMD, OH ^- ions contained in the clay minerals are bound to H ⁺ ions in AMD and water is formed, The clay minerals are neutralized by increasing the pH of the AMD. In addition, since the clay mineral is in an atomized state and is in a calcined state at a high temperature, the ability to neutralize the pH of the natural clay mineral is excellent, and as the negative charge on the surface increases according to the increased specific surface area, Since the pulling force also increases, it functions as a more effective neutralizing agent.

The present invention includes a photo-biological treatment step (S 230) by selecting a micro-algae for microbial algae and removing microbial contaminants from the neutralized mine drainage using the microalgae.

The photobiological treatment step (S 230) by the microalgae comprises a first step of selecting microalgae for fermentation and culturing and propagating, and a step of adding a culture of the microalgae to the neutralized mine drainage, And then proceeds to the second step of removing heavy metal contaminants in the waste water.

In order to treat mine drainage, it is preferable to select micro-algae for the treatment of mine drainage, cultivate selected microalgae at a constant temperature and culturing condition, grow for 7 to 12 days, and then enter the photobioreactor.

The present invention is based on the selection of micro-algae from various microalgae. Unlike microalgae for seawater, the microalgae for drinking water contain microalgae that can survive well in water that does not contain salt and can proceed with photobiological reactions in such water. Since the micro-algae are neutralized at the stage of strong acidity in the mine drainage, the photobioreaction can proceed much more easily. Examples of the micro-algae for embankment include Chlorella vulgaris , Scenemus sp., Botryococcus braunii , Eudorina unicocca , Microcystis sp., Navicula sp. And the like may be exemplarily shown, but the present invention is not limited thereto.

Preferably, the microcavity is cultured in a JM medium (Jaworski's Medium, Thompson et al., 1988) and cultured for 7 to 12 days at a constant temperature of 22 ° C ± 2 ° C. Specific components of the JM medium are introduced in the following examples. It is preferable that the culture and propagation conditions of the microorganism containing the above-mentioned buffer solution are maintained at a pH (7.2 ± 0.3) and the period of the day (8 hours) and the night (16 hours).

The above-mentioned microorganism of the present invention can be used as it is after completion of the above-mentioned culture and propagation, but it is more preferable to use the microalgae by refining them. To this end, the cultured microalgae of the dipping microalgae are separated by a centrifuge into a supernatant and a culture, and then the supernatant is discarded by about 50% to 70% of the initial culture, and the remaining concentrated, It is advisable to use the microalgae culture as a 'purified microalgae culture for the water.'

In the present invention, the neutralized mine drainage and the culture of the microalgae are mixed at a volume ratio of 10: 0.5 to 3 (v / v) and kneaded at room temperature for 1 to 6 days while supplying air from the outside. In this process, the micro-algae-bearing microalgae are used as a feed for the heavy metal component in the mine drainage, and the heavy metal contaminants in the mine drainage are naturally removed.

In the present invention, 0.5 liters to 3 liters of the above-mentioned culture medium for microcavities for drinking water is added to 10 liters of the mine drainage inside the processing vessel and mixed. When the culture medium for microbial algae containing 10 liters of the mine drainage is fed at a rate of 0.5 liters or less, a long biological treatment period is required, which lowers pollutant removal efficiency of mine drainage, However, when the culture of the microalgae containing the above-mentioned microalgae is fed at a rate of 3.0 liters or more, the biological treatment period can be shortened. However, since the microalgae are required to bear an excessive cost for culturing the microalgae, Can not do it.

The present invention is characterized in that the mineral wastewater and the culture medium for microbial algae are slowly mixed in the processing vessel at room temperature for about 1 to 6 days, It feeds the material as a nutrient and induces it to grow. Such photobioreaction seems to be sufficient for about one to four days at room temperature. Typically, the room temperature may range from about 15 ° C to 30 ° C in summer, and from about 10 ° C to 25 ° C in winter, although there may be slight differences between summer and winter. In general, longer periods of incubation are required at lower temperatures, and higher nutrient removal efficiencies can be achieved even at shorter periods of incubation at higher temperatures.

Preferably, the photobioreaction introduces air and light from the outside into the inside of the processing vessel into which the microbes are introduced. The air serves as a means for supplying CO ₂ gas, and the light is used as an energy source for the micro-algae for photosynthetic action. When the air is supplied to the inside of the container, CO ₂ gas in the air is dissolved in the mine drainage, and the micro-algae are used for CO ₂ gas and light energy to perform a photosynthetic action. In addition, when air is supplied from the outside, the air bubbles up inside the processing vessel to rise upward, and the mineral wastewater is kneaded naturally in the process. In this kneading process, the micro-algae are continuously brought into contact with various contaminants in the mine drainage.

It is preferable that the photobioreaction utilizes a light supply medium that uniformly supplies light from the outside. The light supply medium can uniformly supply light generated from the outside to the mine drainage inside the container, thereby contributing greatly to the micro-algae present in the mine drainage performing the photosynthesis action together with the CO ₂ gas It is because. As such a light supply medium, a light guide plate (OP: Optical Panel) can be exemplified. The light guide plate may utilize those conventionally used in photobioreaction. Preferably, the light is provided through a light source, illuminated for 8 hours during the day, and blocked for 16 hours at night. (See Fig. 2).

The micro-algae are further grown in the inside of the container by using various kinds of salts remaining in the mine drainage as a nutrient source. Accordingly, the micro-algae can be proliferated exponentially in the mine drainage, thereby establishing a basis for biomass utilization. This means that when the heavy metal contaminants in the mine drainage are grown as a prey and the heavy metal components in the mine drainage are removed, the effect of the net gain is obtained.

In addition, since the micro-algae are grown by feeding various nutrients present in large quantities in general wastewater or industrial wastewater, even when these nutrients are simultaneously contained in the mine drainage, they can be effectively used as a removal means . Representative examples of such nutrients include dissolved inorganic nitrogen (N), dissolved inorganic phosphorus (P), ammonia, nitrite, nitrate, organic nitrogen compound, inorganic phosphate, organic phosphate, silicate and the like.

In the present invention, a finishing treatment step (S 240) for removing microbial algae grown by absorbing heavy metal contaminants after the photobiological treatment step (S 230) by the microalgae and discharging the treated water from which heavy metal contaminants have been removed, .

The present invention collects the microalgae grown from the heavy metal pollutants as a food in the processing vessel through the photobiological treatment step (S 230) by the microalgae. The collection method of the microalgae is not particularly limited. Iron oxide or the like which is commonly used in the interior of the treatment vessel is injected so that the microalgae are precipitated to the bottom and then the microalgae can be obtained through an outlet provided at the lower end of the treatment vessel. The microalgae have an advantage that they can be utilized as biological resources of new biomass.

In the present invention, the micro-algae are collected and then the treated water remaining in the treatment vessel is discharged to the outside while the heavy metal contaminants and the micro-algae are removed.

Hereinafter, the present invention will be described as a more specific example.

<< Example 1: Neutralization of AMD by Clay Mineral Neutralizing Adsorbent >>

The experiment was conducted by collecting AMD from Y mine in Kangwon province. As a result of the measurement of the mine drainage of the Y mine in Kangwondo, a large amount of heavy metal components were detected and are shown in Table 1 below.

Mine drainage (AMD) composition and measurement results of Y mine    The detected component        Measured value    pH     2.41 (2.28-2.50)    DO [mg / L]     4.35 (3.10-4.88)    Water Temp. [° C]     12.10 (10.80-14.7)    Eh [mV] (redox potential)     322.28 (305.1-351.40)    EC [uS / cm] (electrical conductivity)     2295.00 (2070-2570)    Cu     22.78 (20.11-26.78)    Fe     137.48 (140.83-225.80)    Zn     19.77 (17.39-23.57)    As     0.45 (0.16-0.67)    CD     0.27 (0.15-0.36)    Mn     10.35 (9.23-11.95)

(ISTEK, EC-40N), DO (ISTEK, pH-20N), water temperature and EC were measured using the EC / TDS / Salinity meter Was measured using a DO / O ₂ / air meter (ISTEK, DO-30N) and acidity using a pH meter (SevenGO pro, Mettler Toledo). Fe, Cu, Zn, Mn, As, and Cd in the mine drainage were analyzed using an inductively coupled plasma atomic emission spectrometer (Perkin-Elmer, Optima 3300XL). The concentration of heavy metal ion in the AMD was in the order of Fe>Cu>Zn>Mn>As> Cd, and the Fe content was the highest.

A montmorillonite binder (calcined lime) was mixed at a weight ratio of 85:15 to 10 liters of AMD of the Y mine and calcined at 650 ° C and 1150 ° C to cool the clay mineral neutralized adsorbent to 1.5 kg, Lt; / RTI &gt;

While stirring was carried out, the pH change state of AMD of the Y mine was measured at intervals of 30 minutes from the beginning. As a result of the measurement, it is believed that the above-mentioned AMD was rapidly proceeding the neutralization reaction from the beginning.

FIG. 3 is a graph showing the neutralization process of the mine drainage by time.

In fact, the pH of the solution was about 5.5 at 30 minutes, and the solution showed a neutral pH of 6.8 ± 0.76 at 90 minutes. Therefore, the acidity in the mine drainage was considered to be neutralized for at least 90 minutes, and it was considered sufficient to use conventional drinking water microalgae. There was no significant change after 90 minutes, but 7.3 +/- 0.87 after 180 minutes, indicating that the AMD could be almost completely neutralized.

<< Example 2: Absorption of heavy metals by AMD by clay mineral neutralization adsorbent >>

The procedure of Example 1 was carried out for 3 hours. More specifically, the Y mine drainage and the clay mineral neutralization adsorbent were kneaded for 3 hours, and then the adsorption of each heavy metal component was measured. The results are presented in Table 2 below.

  Removal rate of heavy metal adsorption in Y mine drainage     Fe     Cu     Zn     Mn     As    CD Initial
concentration
[mg / L]
137.48
22.78
19.77
10.35
0.45
0.27 End
concentration
[mg / L]
107.99
17.31
15.42
8.45
0.36
0.22 Removal [%]
 21.45  24.01  22.00  18.36  20.00  18.52

As a result of measurement, 21.45% of Fe, 24.01% of Cu, 22.00% of Zn, 18.36% of Mn, 20.00% of As, 18.00% of As, and 18.52% of As from the AMD of the Y mine according to the adsorption ability of the clay mineral neutralization adsorbent, Was adsorbed and removed.

The sericite consists mainly of SiO _{2 ,} Al ₂ O _{3 ,} Fe ₂ O ₃ , CaO, MgO and the like, among which SiO ₂ And Al ₂ O ₃ contain about 68 ~ 80% depending on the production area of sericite. SiO ₂ Components such as Al ₂ O ₃ are connected in the form of tetrahedrons or octahedrons in a chained form in the plate-like structure of the main component, and various alkali metals and alkaline earth metal ions are contained in this structure. In this case, K ⁺ may have a cation exchange ability, and because he becomes electrically negative if the the Si ^{4 +} in the tetrahedral positions Al ^{3 +} a certain amount of replacement, it becomes a combined cation here, addition surface area per unit mass Is very large and has a surface area of 500 to 1000 m ² per 1 g. Through these surface areas, it is presumed that the ion exchange group is generated and adsorbed and removed the heavy metal components in the process.

As a result, the present invention confirms that the use of the clay mineral neutralization adsorbent can neutralize the mineral wastewater and partially adsorb and remove the heavy metal components in the mineral wastewater.

<< Example 3: Cultivation and proliferation of microalgae >>

The present invention selected spherical chlorella ( Chlorella.sp : FC-16) having a size of 3 to 8 μm as microalgae . The Chlorella . sp was cultured in JM medium (Jaworski's Medium, Thompson et al., 1988), which was purchased from Korean Marine Microalgae Bank (KMMCC, Kores). Culturing conditions were proliferated for 7 days in a thermostat (23 ° C ± 1 ° C) with a cycle of pH (7.2 ± 0.3), day (8h) and night (16h).

The constituents of the JM medium were 4.0 g Ca (NO ₃ ) ₂ .H ₂ O, 2.48 g KH ₂ PO ₄ , 10.0 g MgSO ₄ .H ₂ O, 3.18 g NaHCO ₃ , 0.45 g _{EDTAFeNa, 0.45 g EDTANa 2, 0.496} g H 3 BO 3, 0.278 g MnCl 2 and _{H 2 O, 0.20 g (NH} 4) 6 Mo 7 O 24 and _{H 2 O, 0.008 g cyanocobalamin,} 0.008 g thiamine HCl, 0.008 g biotin, was 16.0 g NaNO ₃ and Na ₂ HPO ₄ and g 2H 7.2 O _2.

&Lt; Example 4: Treatment with microalgae of neutralized mine drainage &gt; >

The microbial cultures cultured and propagated according to Example 3 were mixed with the neutralized mine wastewater according to Example 2 to conduct the photobioreaction. Chlorella cultured for 7 days against 37 L of mine drainage at Y mine in Gangneung City . 3.7 liters of sp cultures were added to mix the mine drainage and microalgae at a volume ratio of 10: 1. Chlorella initially injected . The concentration of sp was 1.12 ± 0.6 g / L.

Mine drainage of said Y mine and said Chlorella . In order to treat the wastewater solution mixed with the sp culture, a treatment apparatus as shown in Fig. 2 was used.

The capacity of the processing vessel was 45 L [450 mm (width) * 300 mm (length) * 330 mm (height)]. The initial microalgae concentration was 1.12 ± 0.6 g L ^-1 and the neutral pH was maintained at 7.2 ± 0.3. The treatment temperature was 25 ° C ± 2 ° C and the cycle of day (8 hours) and night (16 hours) Respectively. A light guide plate (OP) was placed inside the processing container, and light was uniformly supplied using an LEDs lamp. At that time, the wavelength of the light was 430 to 670 nm and proceeded for 6 days. Since the light distribution inside the processing vessel was measured at a depth of 305 mm at 94%, it was found that at least 90% of light was uniformly diffused into the inside of the processing vessel. In addition, the treatment vessel was charged with 0.5 L of air per minute, and the amount of CO ₂ contained in the air was 0.02 vvm.

The processing vessel is connected to a plurality of measurement sensors connected to a computer to measure concentrations of heavy metal pollutants in the mine drainage, and circulation of mine drainage is continuously conducted through a circulation pump.

<< Example 5: Removal Efficiency of Heavy Metal Contaminants in Mineral Drainage >>

During the experiment according to Example 4, the concentration of heavy metal contaminants in the mine drainage of the Y mine was measured through a plurality of measuring sensors connected to a computer, and the following heavy metal pollutant removal phenomenon was confirmed .

That is, the mine drainage of the Y mine is neutralized, and then the Chlorella . The removal efficiency of heavy metals was 94.89% for Fe, 95.34% for Cu, 94.16% for Zn, 88.99% for Mn, 83.33% for As, and 80.59% for Cd, respectively. .

4 is Chlorella After neutralizing the mine drainage. The results of the photobioreactor using SP showed the removal rate of heavy metal contaminants.

The growth of plants requires 15 elements: inorganic nutrients (C, H, O, N, P, K, S, Ca, Mg, Fe, Mn, Cu, Zn, B and Mo) The removal rate of Fe, Cu, Zn and Mn was about 8 ~ 10% higher than that of As or Cd in Example 5, because Fe, Cu, Zn, and Mn were found to be in the growth of microalgae Because it is a necessary trace element, it is estimated that the removal rate is higher than that of As or Cd. Therefore, it can be seen that trace elements (Co, Mo, Ca, Mg, Cu, Zn, Cr, Pb and Se) which are harmful to human body can be removed when microalgae is used for removing heavy metals in mine drainage.

&Lt; Example 6: Amount of biomass obtained when treating mine drainage &gt; >

While the experiment according to Example 4, the Chlorella daily at the same time. sp. The biomass yield was 2.95 g / L at 6 days at the initial concentration of 1.12 g / L, which was 2.63 times higher than the initial concentration. Chlorella sp. Showed a continuous increase in production until day 4, but slowed down from day 4 and there was no significant change at day 5 or 6.

5 is a graph showing the production amount of the biomass obtained in the experiment according to the sixth embodiment.

While the present invention has been particularly shown and described with reference to the preferred embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, The range is determined and limited by the range.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

Claims (2)

A pretreatment step (S 210) of collecting acidic mine drainage of pH 2.28 to 2.50 discharged from abandoned mine or mine, removing floating matters and contaminants from the mine, and allowing the mine drainage to stand for a certain period of time in the flow control tank until moving to the next step;
A neutralization treatment step (S 220) of the mineral wastewater for neutralizing the mineral wastewater to pH 7.3 ± 0.87 by adding 15 kg of clay mineral neutralization adsorbent to 10 L of the pre-treated mineral wastewater and kneading for 3 hours;
Chlorella (sp . FC: 16), 3 ~ 8μm in size, was prepared from microalgae as a microalgae, and the microalgae cultures were prepared. The concentrations of neutralized mine drainage and initial chlorinated chlorella were 1.12 ± 0.6g / L was introduced into the treatment vessel at a volume ratio of 10: 1 (v / v), and the pH was adjusted to 7.2 ± 0.3 and the treatment temperature was maintained at 25 ± 2 ° C. Light having a wavelength of 430 nm to 670 nm using an LEDs lamp from outside and air having a CO ₂ amount of 0.02 vvm were supplied at a rate of 0.5 L / min, and light was emitted at room temperature for a period of 8 hours and a period of 16 hours The microalgae remove the heavy metal contaminants in the mine drainage by photobiological reactions in which the micro-algae are fed with nutrients in the mine drainage to remove heavy metal contaminants in the mine drainage, (S2 &lt; / RTI &gt;30); And
A finishing treatment step (S 240) of discharging the treated water through the photobiological treatment step (S 230) and separately obtaining microalgae grown by absorbing heavy metal contaminants in the previous step; Lt; / RTI &gt;
The clay mineral neutralization adsorbent was prepared before the photobiological treatment step (S 230), and 85 wt% of the sericite, which is a fine particle viscosity mineral of 300 to 600 mesh size, and 15 wt% of lime were uniformly mixed and then calcined at 650 ° C Firstly calcined, and secondarily calcined at 1150 ° C and then cooled,
In the microalgae treatment step (S 230) with the microalgae, the microalgae were cultured in a culture medium under the conditions of pH 7.2 ± 0.3 and 23 ± 1 ° C in a culture medium, (16h) for 7 days,
In the photobiological treatment step (S230), circulation of the mine drainage is induced by using a circulation pump, the concentration of heavy metal pollutants in the mine drainage is measured using a measurement sensor connected to a computer,
The removal rate of heavy metals contained in the mine drainage is 94.89% for Fe, 95.34% for Cu, 94.16% for Zn, 88.99% for Mn, 83.33% for As and 80.59% for Cd. Processing method. The method according to claim 1,
In the finishing step (S 240), iron oxide is injected into the processing vessel provided with the microalgae to precipitate the microalgae into the lower part of the processing vessel, and then the microalgae is obtained through an outlet provided at the lower end of the processing vessel and,
Wherein the treated water discharges the treated water remaining in the treatment vessel to the outside after removing the heavy metal contaminants and microalgae.

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