GB2606659A

GB2606659A - Method and system for biologically treating acidic mine wastewater while recovering iron ion

Info

Publication number: GB2606659A
Application number: GB2209872.7A
Authority: GB
Inventors: Zhou Lixiang; Wang Xiaomeng
Original assignee: Nanjing Agricultural University
Current assignee: Nanjing Agricultural University
Priority date: 2019-12-16
Filing date: 2020-01-17
Publication date: 2022-11-16
Anticipated expiration: 2040-01-17
Also published as: GB2606659A9; WO2021120364A1; GB2606659B; CN111620444B; GB202209872D0; CN111620444A

Abstract

Disclosed is a method for biologically treating acidic mine wastewater while recovering iron ions. The method includes: (1) subjecting acidic mine wastewater to biomineralization by means of acidophilic iron-oxidizing bacteria, then subjecting same to a circulating biological reduction treatment by means of acidophilic iron-reducing bacteria, and then entering same into an alkali adjustment tank (8) for circulation adjustment of the pH, then discharging water and circulating same to a biomineralization unit (1) for a circulating treatment; and (2) after the reaction is carried out for a period of time, bringing the wastewater out from the end of an advection cistern (5), which subsequently can be connected with a lime neutralization treatment system, wherein in the biomineralization unit (1), a jarosite mineral or schwertmannite can be recovered. Also disclosed is a system for biologically treating acidic mine wastewater while recovering iron ions.

Description

METHOD AND SYSTEM FOR BIOLOGICALLY TREATING ACID

MINE DRAINAGE AND RECOVERING IRON IONS

TECHNICAL FIELD

The present invention belongs to the field of wastewater treatment and relates to a method and a system for biologically treating acid mine drainage and recovering iron ions.

BACKGROUND

Acid mine drainage (AMD) is a challenging environmental problem in the mining industry worldwide today. The low-pH and high-iron ion content drainage is generated after biological and chemical reactions in a process of mining or waste slag accumulation. The ANID is typically characterized by extreme acidity (pH: 2.0-3.5), high concentration of sulfate (S042-: 2,000-6,000 mg/L) and soluble iron (Fe 2-or Fe3+: 500-4,500 mg/L), and toxic metals (As, Cd, Cu, Pb, Ni, etc.). The direct discharge of the AMD seriously threatens water and soil environment and an ecological system around mining areas, and brings great loss to production and life of people.

A neutralization and precipitation method are relatively mature for treating the AMD. Briefly, alkaline reagents such as lime or limestone are used to neutralize acidity. Metal ions and sulfate in AIVID can be precipitated by acid-base neutralization reaction, thus the drainage is purified. However, there are still many problems in the method: (t) a large amount of the iron ions and sulfate existing in the AMD are easy to produce a flocculent precipitate to cover the surface of the lime in the neutralization process, such that neutralization efficiency is reduced and the required amount of lime used to neutralization is greatly increased; (2) a large amount of the iron ions and sulphate ions are directly co-precipitated and difficult to recycle, which lead to waste of resources; and (3) a large amount of the neutralized residue/sludge will be generated after lime neutralization treatment and it cannot be used to extract useful metal due to low content of metal. Thus, it is difficult to safely dispose sludge. Obviously, an high concentration of iron and sulfate in the AN/ID essentially limits the practical application of the lime neutralization method. The iron and sulfate ions in the in-situ AIV1D environment are removed through pretreatment, and the pre-treated drainage enters a lime neutralization treatment system, such that the defects existing in the traditional lime neutralization treatment can be fundamentally overcome.

The iron and sulfate ions in the AMD are precipitated in the form of minerals. As a result, useful ions are synchronously recovered and ANID is easily purified. In addition, the AMD treatment technology mainly based on sulfate reduction is widely studied in recent years. Sulfate-reducing bacteria can utilize hydrogen or organic matters as an electron donor and reduce sulfate into sulfide ions, while the pH value of the solution is increased. Meanwhile, the generated biogenic sulfide ions can form a corresponding sulfide precipitate with metal ions (Fe, Zn, Cu, etc.) in the ANID to be recovered. The Chinese patent 200910038782.7 disclosed a method for reducing sulfate in AN4D and precipitating metal ions by using Ofrobacter, thus metal ions were completely converted into a sulfide form and beneficial to recycling. The Chinese patent 200810054487.6 also disclosed a biological treatment process for AMD mainly by using sulfate-reducing bacteria, thus elemental sulfur was recovered and the drainage was treated. S' reduced from S01' can precipitate metal ions, thus the metals in ANID is recycled and AMD is subjected to harmless treatment. However, the stability of a biological treatment system based on sulfate reduction is not easy to control. Most sulfate-reducing bacteria are heterotrophic and obligate anaerobic microorganisms and extremely sensitive to the oxygen content, pH value, carbon source types, and metal ions in the system. It is reported that a large amount of iron ions in ANID can inhibit the activity of the sulfate-reducing bacteria and reduce sulfate-reducing capability by 39-100%. Although some enhancing methods can improve tolerance of a bioreactor, such as biological enhancement is conducted by using mixed bacteria, the methods cannot completely solve problems of carbon source addition, absolute anaerobic conditions, and neutral pH requirement (pH 5-7). In addition, the Chinese patent 201610153310.6 disclosed an AN4D treatment system based on biomineralization. The AMID passed through a bio-oxidation mineralization unit to generate secondary iron minerals to remove a part of iron ions and sulfate, so as to reduce a treatment burden of subsequent lime neutralization. The method realizes a mineralization process by using in-situ Acidithiobacilhis.ferrooridans, but has a relatively low biomineralization efficiency. Besides, when the microorganisms are directly used for AMD treatment, the microorganisms are easy to lose and difficult to be completely used in an actual ANID treatment process. Therefore, it is still a difficult problem to be solved in the current environmental field and necessary to develop a novel treatment process for recycling and harmlessly treating ANID.

SUMMARY

In view of the above-mentioned problems, the present invention provides a system for biologically treating acid mine drainage and recovering iron ions.

Another object of the present invention provides a method for biologically treating acid mine drainage and recovering iron ions.

The objective of the present invention may be achieved by the following technical solutions.

A system for biologically treating acid mine drainage and recovering iron ions includes a biomineralization unit, a bio-reduction tank unit, and an alkali adjustment tank unit. The biomineralization unit includes two parts: multi-stage water-drop aeration tanks at a front end and an advection water collecting tank at a rear end. The bio-reduction tank unit includes a water distribution tank and a bioreduction tank. The alkali adjustment unit includes an alkali adjustment tank and a water distribution tank. A water outlet of the alkali adjustment unit is connected with a top end of the biomineralization unit through a circulating pump and a pipeline to form a circulating acid mine drainage treatment system.

The biomineralization unit (1) may be preferably provided with an internal circulation: a tail end of the advection water collecting tank (5) may be circulated to a top end of the first-stage water-drop aeration tank (4) through a circulating pump and a pipeline.

As a preference of the system of the present invention, a bottom part of the bio-reduction tank (7) may communicate with a top part of the tank through a circulating pump and a pipeline.

As a preference of the system of the present invention, a tail end of the water distribution tank (9) and the alkali adjustment tank (8) may be provided with an internal circulation and connected through a circulating pump and a pipeline.

As a preference of the system of the present invention, the multi-stage water-drop aeration tanks and the advection water collecting tank of the biomineralization reaction unit may be all filled with an Acidithiobacdhis.ferrooxidans* biofilm, while the bio-reduction tank may be filled with an Acid/phi//urn ayptum biofilm As a preference of the system of the present invention, the biomineralization reaction tank may be wide and shallow, and the bio-reduction tank may be narrow and deep. ;As a preference of the system of the present invention, the number of water-drop aeration stages of the water drop aeration tanks may be greater than 3; and an S-shaped backflow plate may be arranged in the advection water collecting tank of the biomineralization unit. ;A method for biologically treating acid mine drainage and recovering iron ions includes the following steps: addtionally adding a certain amount of a culture medium for Acidithiobacillus ferrooxidans to acid mine drainage, introducing an obtained mixture into a system for cyclic biomineralization-bioreduction-biomineralization, and recovering jarosite or schwertmannite in the biomineralization unit. ;The method for biologically treating acid mine drainage and recovering iron ions may preferably include the following steps: introducing acid mine drainage into the system of the present invention for a cycle treatment to recover jarosite or the schwertmannite, where specifically a process is as follows: directly introducing drainage into the biomineralization unit, oxygenating the drainage through the water-drop aeration tanks, conducting biomineralization under the action of the Acidithiobacillus ferrooxidans, passing the drainage through the advection water collecting tank for further mineralization, constructing multiple cycles of the biomineralization through the tail end of the advection water collecting tank and the top end of the water drop aeration tank via a peristaltic pump to promote a mineralization precipitation rate; passing the drainage through the advection water collecting tank to consume a part of oxygen, smoothing the drainage through the water distribution tank, passing the drainage into the bioreduction tank, reducing unmineralized iron ions into ferrous ions under the action of the Acidiphdium crypium and improving reduction efficiency through the internal circulation of the bioreduction tank; passing the reduced drainage into the alkali adjustment tank to increase a pH of the solution to meet a solution requirement of the Acidithiobacillus lerrooxidans in a next cycle treatment process and fully adjusting the pH of the solution through an internal circulation process of the alkali adjustment tank; passing the drainage into a next batch of a treatment system from the water distribution tank; and after multiple cycle treatments, recovering jarosite or the schwertmannite from a bottom part of the biomineralization unit and an Acidithiobacillus.ferrooxidans biofiller. ;As a preference of the system of the present invention, Acidninobacillus.ferrooxidans may be aerobically cultured and colonized on a composite biofiller to prepare an Acidithiobacillus ferrooxidans biofilm. Specifically, Acidithiobacillus ferrooxidans is cultured by using a liquid medium containing 3.5 g/L of (N414)2SO4, 0.58 g/L of MgSO4.7H20, 0.055 g/L of KC1, 0.029 g/L of KH2PO4.3H20, 0.0168 g/L of Ca(NO3)2.4H20 and 22.4 g/L of FeSO4.7H20 with a pH of 2.5. A pure strain at 20% (volume/volume) inoculation amount is used for the first time, an effluent containing bacteria from the previous batch is directly used for inoculation subsequently, the inoculation volume is gradually reduced (20-5%), and the strain is colonized after 3-5 batches of culture for 3-5 days per one. ;coptum are statically cultured and colonized on a composite biofiller to prepare an Acidiphihum cryphun biofilm. A culture medium for Acidiphihum cryphun has a formula as: 0.15 g/L of (NH4)2SO4, 0.5 g/L of IVIgSO4.7H20, 0.05 g/L of KC1, 0.05 g/L of KH2PO4i3H20, 0.0144 g/L of Ca(NO3)24H20, 0.2 g/L of a yeast extract, 1 g/L of C6H1206 and 8.92 g/L of Fe2(SO4)3.3H20 with a pH of 2.8. An inoculation amount (volume/volume) is 20% each time. A pure strain is used for the first time, an effluent containing bacteria from the previous batch is directly used subsequently and the strain is colonized after 3-5 batches of culture for 7-12 days per one. ;As a preference of the system of the present invention, Acidilhiobacillus.ferrooxidaus may be Acidithiobacillus ferrooxidans LX5 and preserved in the China General Microbiological Culture Collection Center with the preservation number of CGMCC No. 0727; and Acidiphilium cryptum may be Acidiphilium.sp. JZ-6 and preserved in the China General Microbiological Culture Collection Center with the preservation number of CGMCC No. 11036. ;As a preference of the system of the present invention, the culture medium for Acidithiohacillus ferrooridans at a concentration of 1/10-1/2 may be additionally added into acid mine drainage to provide necessary nutrients for growth of the bacteria. ;As a preference of the system of the present invention, the number of water-drop aeration stages of the water drop aeration tanks may be greater than 3. ;As a reference of the system of the present invention, an S-shaped backflow plate may be arranged in the collecting tank of the biomineralization unit. ;As a reference of the system of the present invention, the drainage may be circulated from the tail end of the advection water collecting tank of the biomineralization unit to the top end of the water drop aeration tank at a backflow rate of 0.4-0.8 L/min. ;As a reference of the system of the present invention, the drainage may be circulated from a bottom part of the bioreduction tank to a top part of the tank at a backflow rate of 0.8-1.2 L/min As a reference of the system of the present invention, an effluent of the water distribution tank of the alkali adjustment unit may be recycled into the adjustment tank at a backflow rate of 0.05-0.2 L/min. ;As a reference of the system of the present invention, a circulating flow rate from the tail end of the alkali adjustment unit to the top end of the water drop aeration tank of the biomineralization unit may be set to 6-10 m L/min and a single biomineralizati on-bi oreducti on-alkali adjustment treatment process may be conducted for 3-7 days. As a reference of the system of the present invention, the alkali adjustment tank may be filled with 45-50 g/L of granular calcium carbonate at a particle size of 1-3 Rm. ;As a reference of the system of the present invention, in the treatment process, the biomineralization unit may have a pH maintained at 1.8-3.0 and an effluent of the alkali adjustment tank may have a pH of 2.0-3.0. ;As a reference of the system of the present invention, in the single biomineralization-bioreduction-alkali adjustment treatment process, 1 g/L of glucose may be added to the bi oreducti on tank and 1/3 of calcium carbonate in the alkali adjustment tank may be replaced. ;Beneficial effects: (1) The screened strains of the present invention which activity is not inhibited by metal ions and other substances in the drainage are suitable for a solution environment of acid mine drainage and can be used for directly treating drainage in an in-situ manner; (2) Acidithiobacillus ferrowridans is aerobic, Acidiphilium cryptum is facultatively aerobic, thus the strains are easy to culture and rapid to grow and a treatment process is not limited by strict anaerobism; (3) a removal rate of iron and sulfate in a single cycle can be obtained through a theoretical calculation, such that an operation period can be accurately regulated and controlled according to actual requirements; (4) the cycle treatment can greatly reduce the content of the metal ions and sulfate in acid mine drainage and obviously reduce a subsequent lime neutralization treatment burden. Consequently, the treated effluent meets the national discharge standard of class II of China (GB 8978-1996); and (5) recovered secondary iron minerals are a friendly-environmental material, which can be used as an adsorption material and a heterogeneous Fenton catalyst for water treatment and soil remediation. ;BRIEF DESCRIPTION OF THE DRAWINGS ;FIG. 1 is a schematic diagram of an experimental device of the present utility model. ;1: Biomineralization unit; 2: Bio-reduction tank unit; 3: Alkali adjustment tank unit; 4: Water-drop aeration tank; 5: Advection water collecting tank; 6: Water distribution tank; 7: Bio-reduction tank; 8: Alkali adjustment tank; and 9: Water distribution tank. ;Preservation information of biological material Aciditheobacillus ferrooxidans LX5 is preserved at China General Microbiological Culture Collection Center, Zhongguancun, Beijing, China on March 13, 2002 with the preservation number of CGMCC No. 0727. ;Acidiphiliwn,sp. JZ-6 is preserved at China General Microbiological Culture Collection Center, Institute of Microbiology, Chinese Academy of Sciences, NO. 3, Yard 1, West Beichen Road, Chaoyang District, Beijing, China on July 2, 2015 with the preservation number of CGMCC No. 11036 ;DETAILED DESCRIPTION ;Technical solutions in the present invention are described in detail with reference to the accompanying drawings and embodiments. ;Example 1 ;A method and a device for biologically treating acid mine drainage and recovering iron ions included the following specific steps: (1) Acidithiobacillms* .ferrooxidcms LX5 (CGMCC No. 0727) was aerobically cultured and colonized on a commercially available elastic hanging film composite filler (Yixing Sumeng Environmental Protection Filler Co., Ltd.) after batch culture: a formula of a liquid medium of Acidithiobucillu.s' jetroarithms LX5 was 3.5 g/L of (NH4)2504, 0.58 g/L of MgSO4.7H20, 0.055 g/L of KCl, 0.029 g/L of KH2PO4.3H20, 0.0168 g/L of Ca(NO3)2.4H20 and 22.4 g/L of FeSO4.7H20 with a pH of 2.5. the liquid medium for Acidithiobacillus.ferrooxidarts LX5 was used for a film hanging treatment, the Acidithiobac/lius ferrooxidans LX5 was cultured in the pure sterile medium at 180 rpm to a bacterial density of 108 cell s/mL and inoculated into an elastic hanging film composite filler in a biomineralization unit at an inoculation ratio of 20%. The first batch inoculation was conducted at an amount of 20% for 5 days, the second batch inoculation or more was conducted at an amount of 10% for 5 days by directly using an effluent, the third batch inoculation was conducted at an amount of 5% for 3 days, and after the 3 batches of the inoculation, Acidithiobacillus ferrooridans was colonized on a biofilm of the elastic hanging film combination filler to form a brown-red Acidithiobacillus ferrooridans biofilm.

(2) Acid:phut:1m ctypturn JZ-6 (CGMCC No. 11036) was statically cultured and colonized on an elastic hanging film composite filler after batch culture: A medium for the Acidiphilium crypt:1m JZ-6 had a formula as follows: 0.15 g/L of (NH4)2504, 0.5 g/L of MgSO4.7H20, 0.05 g/L of KCl, 0.05 g/L of KH2PO4.3H20, 0.0144 g/L of Ca(NO3)2.4H20, 0.2 g/L of a yeast extract, 1 g/L of C6F11206 and 8.92 g/L of Fe2(504)3.3H20 with a pH of 2.8; the Acidiphilium cryptum was statically cultured in the pure sterile medium to a bacterial density of 108 cells/mL and inoculated into a biofiller in a bioreduction unit, the inoculation was conducted for 3 batches with an inoculation amount of 20% for 10 days each time, a pure strain is used for a first batch, an effluent from the following two batches or more was directly used for the inoculation, and after the 3 batches of the inoculation, the Acidiphihum myptum was colonized on a biofilm to form a light yellowAcid/ph/limn cryptmn biofilm.

(3) Acidithiobacillus jerrooxidans biofilm was placed in the wide and shallow water-drop aeration tanks and the advection water collecting tank, the water-drop aeration tanks were arranged at a front end, the advection water collecting tank was arranged at a rear end of the multi-stage water-drop aeration tanks, a cycle of the biomineralization was constructed through a tail end of the advection water collecting tank and a top end of the water drop aeration tank via a peristaltic pump; and Acidiphiliwn ctyptum biofilm was placed in a shallow and deep bioreduction tank and a cycle bio-reduction process was constructed through a bottom end to a top end via a peristaltic pump; and the biomineralizati on unit consisted of five water-drop aeration tanks (with a volume of 3 L) and the collecting tank (with a volume of 15 L). Each water-drop tank was filled with 6 combined fillers and the collecting tank was filled with 30 fillers. A total of 60 combined fillers were filled. A total height of the water drop was 125 cm, an S-shaped backtlow plate was set in the collecting tank, a backflow rate at the tail end of the collecting tank and the top end of the water-drop aeration tank was set to 0.6 L/min and the biomineralization unit had a pH maintained at 1.8-3.0; and the bio-reduction unit had a volume of 30 L, 66 combined fillers were suspended and filled on average, and a flow rate from a bottom part to a top part was set to 1 L/min (4) A rear end of the reduction tank was connected to an alkali adjustment tank, an alkali adjustment unit was provided with an internal circulation, and a tail end of a water distribution tank of the alkali adjustment unit communicates with the top end of the water drop aeration tank to form a cycle treatment system; and the alkali adjustment tank had an effective volume of 3 L and was filled with 150 g of calcium carbonate with a particle size of 1-3 um, an effluent flew back at a rate of 116 mL/min and flew to the top end of the water drop aeration tank at a rate of 8.5 mL/min, a treatment system with a single cycle treatment time of 5 days was constructed, and the pH of the effluent from the alkali adjustment tank was maintained at 2.0-3.0.

(5) A certain concentration of a culture medium was added to acid mine drainageto be processed, an obtained mixture was introduced to a top end of the water drop aeration tank, and a treatment was started; and The composition of the actual acid mine drainage from an abandoned copper mine in Tongling, Jiangxi was shown in Table 1. The medium for Acidithiobacillus ferrooxidans at a half concentration was added to the actual acid mine drainage and the drainage was introduced into the treatment system for a cycle treatment. A single biomineralization-bioreduction-alkali adjustment treatment cycle was 5 days, 50 g of calcium carbonate in the alkali adjustment tank was replaced every 5 days, and 1 WL of glucose was supplemented in the bioreduction tank Table 1 Water quality of acid mine drainage Fe' Al" Zn' Cu' Ni" S042- (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) 2.5 4377 251.8 66.6 103.6 44.3 L96 12248 (6) After operation for several cycles, the drainage was drawn out from the tail end of the biomineralization unit for a subsequent lime neutralization treatment. Brown-red secondary iron minerals were recovered from a bottom part of a biomineralization unit reactor and a Moldier.

After 3 cycles for a total of 15 days, an effluent was neutralized by lime, thus the consumption of lime and the amount of a neutralized sludge can be significantly reduced, the required amount of the lime was reduced from 5.4 g/L to 2.6 g/L, and the amount of neutralized sludge was reduced from 23.8 g/L to 7.4 g/L.

When operation time continued to increase to 26 days (5 cycle treatments), the consumption of the lime and the amount of the neutralized sludge during the subsequent neutralization treatment were reduced to 1.3 g/L and 5.4 g/L respectively, and the content of ions in the neutralized effluent was shown in Table 2 and met the national discharge standard of Class If of China (GB 8978-1996). A reddish-brown precipitate on a bottom part of the biomineralization unit and the biofilm was collected and identified as jarosite with a yield of 16.4 g/L.

Table 2 Concentrations of ions after 26-day cycle treatment coupled with lime neutralization p1-1 Fe" (mg/L) 8.1 0.2 Avt mn2- (mg/L) (mg/L) <0.1 1.3 Zn" Cu" Ni" SW' (mg/L) (mg/L) (mg/L) (mg/L) 0.2 0.3 <0.1 1092

PH

Claims

C LA I M SWhat is claimed is.1. A system for biologically treating acid mine drainage and recovering iron ions, wherein the system comprises a biomineralization unit (1), a bio-reduction tank unit (2) and an alkali adjustment tank unit (3); and the biomineralization unit (1) comprises two parts: multi-stage water-drop aeration tanks (4) at a front end and an advection water collecting tank (5) at a rear end, the bio-reduction tank unit (2) comprises a water distribution tank (6) and a bioreduction tank (7), the alkali adjustment unit (3) comprises an alkali adjustment tank (8) and a water distribution tank (9), and a water outlet of the alkali adjustment unit (3) is connected with a top end of the biomineralization unit (1) through a circulating pump and a pipeline to form a circulating acid mine drainage treatment system.
2. The system according to claim 1, wherein the biomineralization unit (1) is provided with an internal circulation: a tail end of the advection water collecting tank (5) is circulated to a top end of the first-stage water drop aeration tank (4) through a circulating pump and a pipeline; a bottom part of the bioreduction tank (7) communicates with a top part of the tank through a circulating pump and a pipeline; and a tail end of the water distribution tank (9) and the alkali adjustment tank (8) are provided with an internal circulation and connected through a circulating pump and a pipeline.
3. The system according to claim 1, wherein the water-drop aeration tanks and the advection water collecting tank are all filled with Acidithiobacillus.ferrooxidans biofilm; and the bi o-reducti on tank is filled with Acidiphilium cryptum biofilm.
4. The system according to claim 3, wherein a biomineralization reaction tank is wide and shallow, and the bioreduction tank is narrow and deep.
5. The system according to claim 1, wherein the number of water-drop aeration stages of the water drop aeration tanks is greater than 3; and an S-shaped backflow plate is arranged in the advection water collecting tank of the biomineralization unit.
6. A method for biologically treating acid mine drainage and recovering iron ions, comprising the following steps: additionally adding a certain amount of a culture medium for Acidithiobacillus ferrooxidans to the acid mine drainage, introducing an obtained mixture into a system for cyclic biomineralization-bioreduction-biomineralization, and recovering j arosite or schwertmannite in the biomineralization unit.
7. The method according to claim 6, comprising the following steps: introducing the acid mine drainage into the system in any one of claims 1-5 for a cycle treatment to recover the jarosite or the schwertmannite, wherein specifically a process is as follows: directly introducing drainage into the biomineralization unit, oxygenating the drainage through the water drop aeration tanks, conducting biomineralization under the action of Acidithipbocillus jerrooxidans, passing the drainage through the advection water collecting tank for further mineralization, constructing multiple cycles of the biomineralization through the tail end of the advection water collecting tank and the top end of the water drop aeration tank via a peristaltic pump to promote a mineralization precipitation rate; passing the drainage through the advection water collecting tank to consume a part of oxygen, smoothing the drainage through the water distribution tank, passing the drainage into the bioreduction tank, reducing unmineralized iron ions into ferrous ions under the action of Acidiphihum crypt urn and improving reduction efficiency through the internal circulation of the bioreduction tank; passing the reduced drainage into the alkali adjustment tank to increase a pH of the solution to meet a solution requirement of Acidithiobacillus ftrrooxidans in a next cycle treatment process and fully adjusting the pH of the solution through an internal circulation process of the alkali adjustment tank; and passing the drainage into a next batch of a treatment system from the water distribution tank, and after multiple cycle treatments, recovering jarosite or schwertmannite from a bottom part of the biomineralization unit and Acidithiobacillus lerrooxidatts biofiller.
8. The method according to claim 7, wherein Acidithiobacithts.ferrooxidans are aerobically cultured and colonized on a composite biofiller to prepare Acidithiobacillus lerrooxidans biofilm; and Acidiphilium cryptum are statically cultured and colonized on a composite biofiller to prepare Acithphilittm crypttun biofilm.
9. The method according to claim 5, wherein Acidithinficwillits* .ferroaridans is Acidithiobacillus.ferrooxidans LX5 and preserved in the China General Microbiological Culture Collection Center with the preservation number of CGMCC No. 0727; and the Acidiphdium cryptum is Acidiphilitun sp. JZ-6 and preserved in the China General Microbiological Culture Collection Center with the preservation number of CGMCC No. 11036.
10. The method according to claim 7, wherein the culture medium for Acidithiobacillzts.ferrooxidans at a concentration of 1/10-1/2 is additionally added into acid mine drainage.
11. The method according to claim 7, wherein the number of water-drop aeration stages of the water drop aeration tanks is greater than 3.
12. The method according to claim 7, wherein an S-shaped backflow plate is arranged in the advection water collecting tank of the biomineralization unit.
13. The method according to claim 7, wherein the drainage is circulated from the tail end of the advection water collecting tank of the biomineralization unit to the top end of the water-drop aeration tank at a backflow rate of 0.4-0.8 L/min.
14. The method according to claim 7, wherein the drainage is circulated from a bottom part of the bio-reduction tank to a top part of the tank at a backflow rate of 0.8-1.2 L/min.
15. The method according to claim 7, wherein an effluent of the water distribution tank of the alkali adjustment unit is recycled into the adjustment tank at a backflow rate of 0.05-0.2 L/min.
16. The method according to claim 7, wherein a circulating flow rate from the tail end of the alkali adjustment unit to the top end of the water drop aeration tank of the biomineralization unit is set to 6-10 mL/min and a single biomineralizati on-bi oreducti on-alkali adjustment treatment process is conducted for 3-7 days.
17. The method according to claim 7, wherein the alkali adjustment tank is filled with 45-50 g/L of granular calcium carbonate at a particle size of 1-3 um.
18. The method according to claim 7, wherein in the treatment process, the biomineralization unit has a pH maintained at 1.8-3.0 and an effluent of the alkali adjustment tank has a pH of 2.0-3.0.
19. The method according to claim 7, wherein in the single biomineralization-bioreduction-alkali adjustment treatment process, 1 g/L of glucose is added to the bioreduction tank and 1/3 of calcium carbonate in the alkali adjustment tank is replaced.