Method for advanced treatment of acid mine drainage

Abstract

The application relates to the technical field of acid mine drainage treatment, in particular to a deep treatment method of acid mine drainage. The deep treatment method of acid mine drainage comprises the following steps: hydrogen sulfide generation and preliminary removal of heavy metals in the acid mine drainage; further removal of the heavy metals in effluent and synchronous removal of sulfates; and deep removal of residual pollutants in the effluent. The deep treatment method of acid mine drainage provided by the application solves the technical problems of high investment and operation cost caused by large demand of electron donors and carrier gas, complicated process, slow acid mine drainage treatment speed and poor treatment efficiency in the existing acid mine drainage treatment method.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of acid mine drainage treatment, and in particular to an acid mine drainage advanced treatment method. BACKGROUND

[0002] Acid mine drainage (AMD) is one of the most serious environmental problems faced by the mining industry, and untreated AMD will cause serious pollution and damage to the surrounding water, soil and biodiversity, so it is particularly important to develop an efficient AMD treatment technology.

[0003] In the prior art, a method for treating AMD can be an SRB method for treating AMD by using sulfate-reducing bacteria (SRB). The SRB can use various electron donors, such as lactic acid, formic acid, acetic acid, ethanol, H2, CH4, aliphatic hydrocarbons, polyaromatic hydrocarbons, solid carbon sources, etc., to reduce SO4 2- under anaerobic (or anoxic) conditions to produce sulfides to precipitate heavy metals, and to produce alkaline substances to increase the pH and reduce the SO4 2- concentration. However, in practice, the AMD usually lacks the electron donors required by the SRB, and if this method is used, a large amount of electron donors needs to be specially provided for the reaction, which not only has a large demand for the electron donors, but also has a high cost of the electron donors, and it is difficult to implement. In addition, when the content of heavy metals in the AMD is too high, the SRB activity will be inhibited, which may cause slow reaction speed, low treatment efficiency, and even reaction interruption and treatment system collapse in severe cases.

[0004] In the prior art, another method for treating AMD can be a biological reaction and chemical precipitation separation type multi-stage pH control process for treating AMD. SO4 2- is reduced to H2S in a sulfate-reducing anaerobic reactor (in a biological sulfide production system), and then H2S in the reactor is stripped by using a carrier gas (such as N2) to an AMD precipitation tank, and the multi-stage pH is controlled by adding alkali in the AMD precipitation tank (in a metal precipitation system), so as to realize the staged precipitation and selective recovery of various heavy metals. However, first, the separation type multi-stage pH control process is carried out in two independent units, namely the biological sulfide production system and the metal precipitation system, and the process is complicated; second, the separation type multi-stage pH control process needs to obtain and recycle the carrier gas (such as N2), which requires high energy input, has a high cost, and has a large demand, which is not suitable for long-term and large-scale special provision, and additional provision of electron donors required for sulfate reduction and step-by-step addition of alkali is also required, further increasing the cost. SUMMARY

[0005] The application aims to provide an acid mine drainage deep treatment method to solve the technical problems of large demand, high cost, slow AMD treatment speed, low AMD treatment efficiency and complex process in the existing AMD treatment method.

[0006] The application provides an acid mine drainage deep treatment method, which comprises the following steps:

[0007] In step S1, hydrogen sulfide is generated and heavy metals in the acid mine drainage are preliminarily removed, the acid mine drainage is introduced into a pyrite gas production tank in which pyrite and nitrogen are introduced, sulfide precipitate and hydrogen sulfide gas are generated, and then the water is discharged to the next step;

[0008] In step S2, heavy metals in the water are further removed and sulfates are simultaneously removed, the water is sequentially flowed through multiple units of a multiple-unit anaerobic reactor, each unit of which is a sulfate-reducing bacteria reaction zone uniformly inoculated with sulfate-reducing bacteria in a different pH environment, sludge fermentation liquor and alkali liquor are introduced into each unit, organic matter in the sludge fermentation liquor is used as an electron donor, hydrogen sulfide gas generated in step S1 and escaped by nitrogen stripping is added to each unit as needed to assist heavy metal precipitation, the sulfate-reducing bacteria stably reduce sulfates in the water and produce hydrogen sulfide gas, and heavy metal ions are precipitated in multiple units of the sulfate-reducing bacteria reaction zone in different pH values, and the pyrite-sulfide precipitate generated in one unit of the sulfate-reducing bacteria reaction zone is recycled to the pyrite gas production tank in step S1 for use, and then the water is discharged to the next step;

[0009] In step S3, deep purification treatment is performed to deeply remove residual pollutants in the water, the water is introduced into an anaerobic ammonia oxidation reactor inoculated with anaerobic ammonia oxidation bacteria, and the generated nitrogen is recycled to the pyrite gas production tank in step S1 for use.

[0010] Further, in step S2, the sulfate-reducing bacteria reaction zone comprises a first unit, a second unit and a third unit, the pH value of the first unit is controlled to be equal to 3, the pH value of the second unit is controlled to be between 5 and 5.5, the pH value of the third unit is controlled to be between 7 and 7.8, the temperature of the first unit, the second unit and the third unit is controlled to be 37℃, the ORP is lower than-150mV, the COD / SO4 2- ratio is 0.6-0.9, and the HRT is 1-3d, and the pyrite-sulfide precipitate generated in the third unit is introduced into the pyrite gas production tank in step S1 for use.

[0011] Further, in the step S2, the first unit, the second unit and the third unit are all double compartments, each comprising a front-end compartment and a rear-end compartment, each front-end compartment is provided with a first water quality measuring instrument for parameter measurement, each front-end compartment introduces sludge fermentation liquor and alkali liquor, and the amount of hydrogen sulfide generated in the step S1 and escaped by nitrogen blowing is controlled according to the parameter measurement results of the first water quality measuring instrument, when each parameter reaches the biological reaction requirement, the rear-end compartment is introduced for biological reaction, and stirring is carried out at the same time, the parameter measurement of the first water quality measuring instrument includes pH, ORP, COD, SO4 2- and heavy metals.

[0012] Further, the volume number of sulfate-reducing bacteria inoculated sludge in the front-end compartment of the first unit of the multi-unit anaerobic reactor is controlled to be 0-50% of the effective volume of the reaction cavity thereof;

[0013] The volume number of sulfate-reducing bacteria inoculated sludge in the rear-end compartment of the first unit, the double compartments of the second unit and the double compartments of the third unit of the multi-unit anaerobic reactor is controlled to be 25%-50% of the effective volume of the reaction cavity thereof;

[0014] The volume number of anaerobic ammonia oxidation inoculated sludge in the anaerobic ammonia oxidation reactor is controlled to be 75%-90% of the effective volume of the reaction cavity thereof.

[0015] Further, after the step S2, there is also a step S21 of removing the remaining ferrous ions and phosphorus introduced by the sludge fermentation liquor, flowing through the multiple units of the sulfate-reducing bacteria reaction zone of the multi-unit anaerobic reactor and then flowing into the phosphorus removal and iron removal unit of the multi-unit anaerobic reactor, the phosphorus removal and iron removal unit is a double compartment comprising a front-end compartment and a rear-end compartment, the pH value of the front-end compartment of the phosphorus removal and iron removal unit is controlled to be between 6 and 8, so that the ferrous ions and the phosphate generate blue vitriol precipitate and are discharged and collected, if there are still ferrous ions remaining after precipitation, the pH value of the rear-end compartment of the phosphorus removal and iron removal unit is controlled to be between 8.5 and 10 by adding alkali liquor, so that ferrous hydroxide precipitate is generated and discharged and collected, and then the effluent is discharged to the next step.

[0016] Further, after the step S21, there is also a step S22 of water quality adjustment, the effluent of the step S21 flows into the water quality adjustment chamber of the multi-unit anaerobic reactor, the water quality adjustment chamber is provided with a second water quality measuring instrument, the water quality adjustment chamber introduces alkali liquor, and the domestic sewage and the effluent of the aerobic tank are introduced to adjust the water quality of the effluent of the step S21, the measurement parameters of the second water quality measuring instrument include pH, COD, ORP, NH4 + , NO2 - , NO3 - and SO4 2-, control the water quality conditions: pH value is controlled between 6.8-8.3, and the best is 7.27-7.32, ORP control is: -150mV>ORP>-300mV, then the effluent to the next step.

[0017] Further, the step S22 introduced the deployment method of including the main stream of the phosphorus removal domestic sewage and the effluent of the aerobic tank:

[0018] Method one: if the molar ratio of NH4 + and SO4 2- in the effluent is greater than 2, the effluent of the aerobic tank is introduced, the molar ratio of excess NH4 + and NO3 - is controlled to be 1, and the carbon-nitrogen ratio of COD and NO3 - is controlled to be between 0.43-0.75;

[0019] Method two: if the molar ratio of NH4 + and SO4 2- in the effluent is equal to 2, the effluent of the aerobic tank is introduced, and the carbon-nitrogen ratio of COD and NO3 - is controlled to be between 1.07-1.67;

[0020] Method three: if the molar ratio of NH4 + and SO4 2- in the effluent is less than 2, the phosphorus removal domestic sewage is introduced, the molar ratio of NH4 + and SO4 2- is controlled to be 2, and the effluent of the aerobic tank is introduced, and the carbon-nitrogen ratio of COD and NO3 - is controlled to be between 1.07-1.67.

[0021] Further, the deployment of the main stream of the water is precisely controlled by the intelligent water system according to the following molar ratio: reaction one: NH4 + :SO4 2- =2:1; reaction two: NH4 + :NO3 - :TOC=2:2:1; reaction three: NO3 - :TOC=4:5, through equation fitting calculation, the best main stream of water deployment scheme is obtained.

[0022] Further, in the step S3, the internal environmental conditions of the anammox reactor are controlled, the temperature is controlled to be between 30-37℃, and the HRT is controlled to be between 4-8h.

[0023] Further, in the step S1, the pyrite filled in the pyrite gas production tank is obtained from abandoned pyrite tailings of a surrounding mine or the pyrrhotite precipitate generated by the third unit of the multi-unit anaerobic reactor, the particle size of the pyrite is controlled to be 50-200 mesh, and the pyrite is added when the ferrous generation rate is reduced for the second time.

[0024] Compared with the prior art, the acid mine wastewater deep treatment method provided by the present application at least sequentially undergoes the hydrogen sulfide generation and preliminary removal of heavy metals in the acid mine wastewater in step S1, further removal of heavy metals and simultaneous removal of sulfate in the effluent in step S2, and deep removal of residual pollutants in the effluent in step S3, thereby improving the purification degree of the acid mine wastewater and strengthening the treatment of the acid mine wastewater; the pyrite referred to in the pyrite gas production tank in step S1 can be obtained in the heavy metal precipitation in one of the units of the sulfate reducing bacteria reaction zone of the multi-unit anaerobic reactor in step S2 and reused, which is low in cost, free of secondary pollution, and can recover useful metals to realize resource recycling; the nitrogen referred to in the pyrite gas production tank in step S1 can also be obtained and recycled in the anaerobic ammonia oxidation reactor in step S3, which reduces the source cost and realizes resource recycling; the hydrogen sulfide generated in step S1 and stripped by nitrogen can be added to the multiple units of the sulfate reducing bacteria reaction zone in step S2 to assist the sulfate reducing bacteria reaction, and then the multi-unit anaerobic reactor in step S2 can reasonably and efficiently simplify and integrate the biological sulfur production system and the heavy metal precipitation system into one, forming a reaction line, which not only solves the problem of complicated process, but also effectively proliferates the organisms and greatly reduces the investment and operating costs; the organic matter in the sludge fermentation liquid introduced in step S2 is used as an electron donor, the source of the electron donor is wide and the cost is low, and the sludge fermentation liquid and the acid mine wastewater can be treated simultaneously; the anaerobic ammonia oxidation process used in the anaerobic ammonia oxidation reactor in step S3 is an economical and efficient biological technology friendly to the environment, the substrate type of the anaerobic ammonia oxidation bacteria used in the process is diverse, the metabolic form is flexible, the environmental adaptability is strong, and nitrogen, carbon, sulfur and other pollutants can be removed at the same time, and the deep purification treatment capacity is significantly improved; the acid mine wastewater deep treatment method provided by the present application can realize self-production and self-use of nitrogen, hydrogen sulfide, electron donor, pyrite and other important resources required in the reaction, treat waste with waste, and independently recycle and reuse, which greatly reduces the cost of the above resources, and solves the problem of high cost caused by the large use of nitrogen, hydrogen sulfide, electron donor, pyrite and the like. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art of the present application, the drawings needed to be used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0026] Figure 1 Flow chart of the acid mine drainage water advanced treatment method provided by the embodiments of the present application;

[0027] Figure 2 Flow chart of the acid mine drainage water advanced treatment method provided by the embodiments of the present application in application. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art on the basis of the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0030] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0031] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the application is used, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0032] In addition, the terms "horizontal", "vertical", "overhang" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that it is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0033] In the description of the present application, it should be further pointed out that unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0034] Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The following examples and features in the examples can be combined with each other without conflict.

[0035] As shown in Figure 1 and Figure 2 The embodiment of the present application provides a method for deep treatment of acid mine drainage, which comprises the following steps:

[0036] Step S1, hydrogen sulfide generation and preliminary removal of heavy metals in acid mine drainage (hereinafter referred to as AMD), the AMD is introduced into the pyrite gas tank with pyrite and nitrogen, to generate sulfide precipitate and hydrogen sulfide gas, and then the water is discharged to the next step.

[0037] In the formula, the pyrite is dissolved in the acid mine drainage to generate ferrous ions and sulfur ions, part of the sulfur ions generate sulfide precipitate with part of the heavy metal ions in the acid mine drainage, and the sulfide precipitate is discharged and collected and treated, and can be discharged from the slag discharge port of the pyrite gas tank, and the other part of the sulfur ions generate hydrogen sulfide, which is released and saved after nitrogen stripping, and can be recovered and saved to the hydrogen sulfide storage tank, and then is used in the multiple units of the sulfate reducing bacteria reaction zone of the multiple unit anaerobic reactor in step S2 to assist the sulfate reducing bacteria (hereinafter referred to as SRB) reaction to remove heavy metals.

[0038] The pyrite filled in the pyrite gas production tank in step S1 can be obtained from abandoned pyrite tailings in surrounding mining areas, or from the pyrrhotite precipitate generated in the third unit of the sulfate-reducing bacteria reaction zone in the multi-unit anaerobic reactor in step S2. The source is wide and easy to obtain, and as a waste, it can be used to precipitate heavy metal ions or as a raw material to produce hydrogen sulfide after AMD treatment. Not only is there no secondary pollution, but also useful metals can be recovered, realizing waste treatment with waste and reducing costs. Preferably, the particle size of the pyrite is controlled to be 50-200 mesh. More preferably, when the ferrous ion generation rate is reduced for the second time, pyrite is added, which can be fed into the pyrite gas production tank from the solid inlet.

[0039] The nitrogen gas required in the pyrite gas production tank in step S1 can be obtained from the anaerobic ammonia oxidation reactor in step S3 and recycled, realizing waste treatment with waste, resource recycling, reducing source costs, and solving the problem of high nitrogen gas cost.

[0040] In step S1, not only can a part of the heavy metals in the acid mine drainage be precipitated and removed in this step S1, but also by transporting hydrogen sulfide to the first unit, the second unit and the third unit of the sulfate-reducing bacteria reaction zone of the multi-unit anaerobic reactor, a part of the heavy metal load can be shared and the SRB can be assisted to biologically remove the remaining part of the heavy metals in the acid mine drainage, thereby avoiding the serious damage to the operation of the multi-unit anaerobic reactor caused by the multiple types and high concentrations of heavy metals contained in the acid mine drainage.

[0041] Step S2, further removing heavy metals and synchronously removing sulfates from the effluent, the effluent treated in step S1 can flow through multiple units of a sulfate-reducing bacteria reaction zone inoculated with SRB under different pH environments in sequence, specifically, the sulfate-reducing bacteria reaction zone can include a first unit, a second unit and a third unit, and sludge fermentation liquor and alkali liquor are introduced into each unit (the first unit, the second unit and the third unit) to use the organic matter in the sludge fermentation liquor as the electron donor of SRB, and hydrogen sulfide generated in step S1 and escaped by nitrogen stripping is added to each unit to assist the SRB reaction, so as to stabilize the reduction of sulfates in the effluent, produce sulfides, and further precipitate heavy metal ions in the first unit, the second unit and the third unit of the sulfate-reducing bacteria reaction zone under different pH values, thereby reducing the difficulty of heavy metal separation and improving the recovery rate.

[0042] Specifically, the pH value of the first unit can be controlled to be equal to 3, the pH value of the second unit can be controlled to be between 5-5.5, the pH value of the third unit can be controlled to be between 7-7.8, and the temperature of the first unit, the second unit and the third unit can be controlled to be 37℃, the ORP can be controlled to be lower than-150mV, and the COD / SO4 2-is 0.6-0.9, and HRT is 1-3d, wherein the generated pyrite-magnetic precipitate in the third unit can be introduced into the pyrite gas production tank in the step S1, and then the effluent is discharged to the next step.

[0043] In the step S2, the biological sulfur production system and the heavy metal precipitation system are reasonably and efficiently simplified and integrated into one unit in the multi-unit anaerobic reactor, forming a reaction line, which not only solves the problem of complicated process, but also effectively proliferates the biological body, greatly reduces the investment and operating costs; at the same time, the organic matter in the introduced sludge fermentation liquid is used as the electron donor in the step S2, the source of the electron donor is wide and the cost is low, and the sludge fermentation liquid and the acid mine wastewater can be treated simultaneously.

[0044] In the step S3, the remaining pollutants in the effluent are removed, the effluent is introduced into the anaerobic ammonia oxidation reactor inoculated with anaerobic ammonia oxidation bacteria, and the generated nitrogen is recovered and introduced into the pyrite gas production tank in the step S1.

[0045] Preferably, in the step S3, the internal environmental conditions of the anaerobic ammonia oxidation reactor are controlled, the temperature is controlled at 30-37℃, and the HRT is controlled at 4-8h.

[0046] In the step S3, the anaerobic ammonia oxidation (Anammox) process used in the anaerobic ammonia oxidation reactor is an economical and efficient, environmentally friendly biological technology, the substrate type of the anaerobic ammonia oxidation bacteria used in the process is diverse, the metabolic form is flexible, the environmental adaptability is strong, and the process can simultaneously remove nitrogen, carbon, sulfur and other pollutants, and has a significant deep purification treatment capacity.

[0047] Compared with the prior art, the acid mine drainage deep treatment method provided by the embodiment of the application has the following advantages: the acid mine drainage at least sequentially undergoes the hydrogen sulfide generation and the preliminary removal of heavy metals in the acid mine drainage in step S1, the further removal of heavy metals and the simultaneous removal of sulfates in the effluent in step S2, and the deep removal of residual pollutants in the effluent in step S3, thereby improving the purification degree of the acid mine drainage and strengthening the treatment of the acid mine drainage; the pyrite used in the pyrite gas production tank in step S1 can be obtained in the heavy metal precipitation in one of the units of the sulfate-reducing bacteria reaction zone of the multi-unit anaerobic reactor in step S2 and reused, which is low in cost, free of secondary pollution, and capable of recycling useful metals and realizing resource recycling; the nitrogen used in the pyrite gas production tank in step S1 can be obtained in the anaerobic ammonia oxidation reactor in step S3 and recycled and reused, which reduces the source cost and realizes resource recycling; the hydrogen sulfide generated in step S1 and stripped by the nitrogen can be added to the multiple units of the sulfate-reducing bacteria reaction zone in step S2 to assist the sulfate-reducing bacteria reaction, so that the multi-unit anaerobic reactor in step S2 can reasonably and efficiently simplify and integrate the biological sulfur production system and the heavy metal precipitation system into one, forming a reaction line, which not only solves the problem of complicated process, but also effectively proliferates the organisms and greatly reduces the investment and operation cost; the organic matter in the introduced sludge fermentation liquid is used as an electron donor in step S2, the source of the electron donor is wide and the cost is low, and the sludge fermentation liquid and the acid mine drainage can be treated simultaneously; the anaerobic ammonia oxidation process used in the anaerobic ammonia oxidation reactor in step S3 is an economical and efficient biological technology friendly to the environment, the substrate type of the anaerobic ammonia oxidation bacteria used in the process is diverse, the metabolic form is flexible, the environmental adaptability is strong, and the process can simultaneously remove various pollutants such as nitrogen, carbon, and sulfur, and has a remarkable deep purification treatment capacity; the acid mine drainage deep treatment method provided by the application can realize self-production and self-use of nitrogen, hydrogen sulfide, electron donors, pyrite, and other important resources required in the reaction, waste treatment with waste, and independent recycling and reuse, thereby greatly reducing the cost of the above resources, and solving the problem of high cost caused by the large use of nitrogen, hydrogen sulfide, electron donors, pyrite, and the like.

[0048] A further embodiment, in the aforementioned step S2, the first unit, the second unit and the third unit of the sulfate-reducing bacteria reaction zone of the multi-unit anaerobic reactor can be provided as double compartments, each of which can include a front-end compartment and a rear-end compartment, each front-end compartment can be provided with a first water quality meter for parameter measurement, each front-end compartment introduces the aforementioned sludge fermentation liquid and alkali liquid, and the amount of hydrogen sulfide generated in the aforementioned step S1 and escaped by nitrogen stripping is controlled according to the parameter measurement results of the first water quality meter, when each parameter reaches the biological reaction requirement, the front-end compartment of each unit is introduced into the rear-end compartment for biological reaction, and stirring is carried out at the same time, the parameter measurement of the first water quality meter includes pH, ORP, COD, SO4 2- and heavy metals.

[0049] Because the presence of soluble heavy metal ions in the effluent solution can have a certain toxic effect on SRB, when the concentration is too high, the activity of SRB may even be completely inhibited. Therefore, the hydrogen sulfide generated by the aforementioned pyrite gas generation tank can be introduced into the front-end compartment of the first unit, the second unit and the third unit of the multi-unit anaerobic reactor, which can assist the front-end compartment to carry out stable heavy metal precipitation in a relatively harsh environment, and avoid serious damage to the operation of the biological reactor.

[0050] A preferred embodiment is that the volume number of SRB inoculated sludge in the front-end compartment of the first unit of the aforementioned multi-unit anaerobic reactor is 0-50% of the effective volume of its reaction cavity; the volume number of SRB inoculated sludge in the rear-end compartment of the first unit, the double compartments (including the front-end compartment and the rear-end compartment) of the second unit and the double compartments (including the front-end compartment and the rear-end compartment) of the third unit of the multi-unit anaerobic reactor is 25%-50% of the effective volume of its reaction cavity; and the volume number of anaerobic ammonia oxidation inoculated sludge in the aforementioned anaerobic ammonia oxidation reactor is 75%-90% of the effective volume of its reaction cavity, so as to ensure that the biological reaction involved in the present application has a high reaction rate.

[0051] A further embodiment is that, as Figure 1 and Figure 2As shown, after step S2, a further step S21 may be included to remove the remaining ferrous ions and phosphorus introduced by the sludge fermentation broth. The effluent flows through multiple units in the sulfate-reducing bacteria reaction zone of the multi-unit anaerobic reactor and then into the phosphorus and iron removal unit. This phosphorus and iron removal unit is a double-compartment unit, including a front compartment and a rear compartment. The pH value of the front compartment of the phosphorus and iron removal unit is controlled between 6 and 8, causing ferrous ions and phosphate to form lapis lazuli precipitate, which is then discharged and collected. If ferrous ions remain after precipitation, an alkaline solution is added to the rear compartment of the phosphorus and iron removal unit to control the pH value between 8.5 and 10, generating ferrous hydroxide precipitate, which is then discharged and collected, thereby removing the phosphorus introduced by the sludge fermentation broth and the remaining ferrous ions. The effluent then proceeds to the next step.

[0052] In step S21, lapis lazuli has the characteristics of low solubility, rapid formation, and slow degradation (such as oxidation). Especially in the presence of large amounts of Fe(II) and P, low oxygen environment and low sulfide concentration, the simultaneous removal of iron and phosphorus is very effective.

[0053] A further embodiment is, as follows: Figure 1 and Figure 2 As shown, step S22, water quality conditioning, may be included after step S21. The effluent from step S21 flows into the water quality conditioning chamber of the multi-unit anaerobic reactor. The water quality conditioning chamber is equipped with a second water quality analyzer. Alkaline solution and mainstream influent including phosphorus-removing domestic wastewater and aerobic tank effluent are introduced into the water quality conditioning chamber to condition the effluent from step S21. The parameters measured by the second water quality analyzer include pH, COD, ORP, and NH4. + NO2 - NO3 - and SO4 2- The water quality conditions are controlled as follows: pH value is controlled between 6.8 and 8.3, with 7.27 to 7.32 being optimal; ORP is controlled at -150mV > ORP > -300mV, and then the effluent is discharged to the next step.

[0054] In a preferred embodiment, the method for introducing the mainstream influent, which includes phosphorus-removing domestic sewage and aerobic tank effluent, in step S22 above can be as follows:

[0055] Method 1: If NH4 is released from the water + and SO4 2- If the molar ratio is greater than 2, the effluent from the aerobic tank is introduced to control excess NH4+. + With NO3 - The molar ratio is 1, while controlling COD and NO3. - The carbon-to-nitrogen ratio is between 0.43 and 0.75, and phosphorus-removing domestic wastewater can be introduced simultaneously if necessary;

[0056] Method two: if the molar ratio of NH4 + and SO4 2- in the effluent is equal to 2, the effluent from the aerobic tank is introduced, and the carbon-nitrogen ratio of COD and NO3 - is controlled between 1.07 and 1.67.

[0057] Method three: if the molar ratio of NH4 + and SO4 2- in the effluent is less than 2, phosphorus-removing domestic sewage is introduced to control the molar ratio of NH4 + and SO4 2- to be 2, and the effluent from the aerobic tank is introduced to control the carbon-nitrogen ratio of COD and NO3 - between 1.07 and 1.67.

[0058] The microbiological mechanism of the above-mentioned blending method of the main stream of the influent is as follows: when sulfate remains, anammox bacteria undergoes sulfate-type anammox reaction, which is a biological reaction in which anammox bacteria takes NH4 + as an electron donor and SO4 2- as an electron acceptor, and the reaction product is N2 and S, and the reaction equation is: 2NH4 + + SO4 2- → N2 + S. In method one, the molar ratio of NH4 + and SO4 2- is greater than the stoichiometric ratio, and anammox bacteria removes the excess NH4 + through short-range DNRA-Anammox reaction (i.e., dissimilatory nitrate reduction to ammonium, abbreviated as: DNRA), and the reaction equation is: 4NH4 + + 4NO3 - + CH3COO - → CO2 + HCO3 - + 4N2 + 9H2O, therefore, the effluent from the aerobic tank in the main stream of the influent can be blended to provide NO3 - , and when the carbon-nitrogen ratio of COD and the original excess NH4 + is greater than 0.43-0.75, phosphorus-removing domestic sewage can also be blended to provide a certain amount of external NH4 + , so as to ensure that the carbon-nitrogen ratio of COD and NO3 - is appropriate; the source of the phosphorus-removing domestic sewage is the effluent from the biological phosphorus removal unit or the chemical phosphorus removal unit of the main stream process of municipal sewage; in method three, the molar ratio of NH4 + and SO4 2- is less than the stoichiometric ratio, therefore, the phosphorus-removing domestic sewage in the main stream of the influent can be blended to provide insufficient NH4+ In the method two and the method three, for the convenience of deployment, the anaerobic ammonia oxidation bacteria can remove the residual COD through the DNRA-Anammox reaction, and the reaction equation is: 8NO3 - + 5CH3COO - + 8H + → 5CO2+ 5HCO3 - + 4N2+ 9H2O, so the effluent of the aerobic tank in the main stream water can be deployed to provide NO3 - .

[0059] Further, the deployment of the aforementioned main stream water can be accurately controlled by the intelligent water system according to the following molar ratio: reaction one: NH4 + : SO4 2- = 2:1; reaction two: NH4 + : NO3 - : TOC = 2:2:1; reaction three: NO3 - : TOC = 4:5, through equation adaptation accounting, the best main stream water deployment scheme is obtained.

[0060] The acid mine drainage deep treatment method provided by the embodiment of the application, wherein the pyrite gas tank makes the operation of the multi-unit anaerobic reactor more efficient and stable, and realizes waste treatment with waste; the multi-unit anaerobic reactor realizes the cooperative treatment of sludge fermentation liquid and acid mine drainage through hierarchical pH control, can realize hierarchical precipitation and selective recovery of various heavy metals, and also achieves the purpose of waste treatment with waste; the anaerobic ammonia oxidation reactor not only realizes the deep purification of the tail water of the multi-unit anaerobic reactor, but also bears part of the denitrification load of the main stream of the sewage plant, and reduces the denitrification pressure of the sewage plant.

[0061] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, but not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A method for advanced treatment of acid mine drainage, characterized in that, The method comprises the following steps: Step S1, hydrogen sulfide is generated and heavy metals in the acid mine drainage are preliminarily removed, the acid mine drainage is introduced into a pyrite gas tank in which pyrite and nitrogen are introduced, sulfide precipitate and hydrogen sulfide gas are generated, and then the water is discharged to the next step; Step S2, further removing heavy metals in the water and synchronously removing sulfates, the water is sequentially discharged through a plurality of units of a multi-unit anaerobic reactor, each unit of the multi-unit anaerobic reactor is a sulfate-reducing bacteria reaction zone in which sulfate-reducing bacteria are uniformly inoculated in different pH environments, sludge fermentation liquor and alkali liquor are introduced into each unit, organic matter in the sludge fermentation liquor is used as an electron donor, hydrogen sulfide gas generated in the step S1 and escaped by nitrogen stripping is added to each unit as needed to assist heavy metal precipitation, the sulfate-reducing bacteria stably reduce sulfates in the water and generate hydrogen sulfide gas, and heavy metal ions are precipitated in the plurality of units of the sulfate-reducing bacteria reaction zone in different pH environments, and the pyrite-magnetic pyrite precipitate generated in one unit of the sulfate-reducing bacteria reaction zone is recycled to the pyrite gas tank in the step S1, and then the water is discharged to the next step; Step S21, removing residual ferrous ions and phosphorus introduced by the sludge fermentation liquor, after flowing through a plurality of units of the sulfate-reducing bacteria reaction zone of the multi-unit anaerobic reactor, the water flows into a phosphorus-removing and iron-removing unit of the multi-unit anaerobic reactor, the phosphorus-removing and iron-removing unit is a double-compartment unit including a front-end compartment and a rear-end compartment, the pH value of the front-end compartment of the phosphorus-removing and iron-removing unit is controlled to be between 6 and 8, so that ferrous ions and phosphates generate blue vitriol precipitate and are discharged and collected, if there are residual ferrous ions after precipitation, the pH value of the rear-end compartment of the phosphorus-removing and iron-removing unit is controlled to be between 8.5 and 10 by adding alkali liquor, so that ferrous hydroxide precipitate is generated and discharged and collected, and then the water is discharged to the next step; Step S22, water quality adjustment, the water flow from step S21 to the water quality adjustment chamber of the single unit anaerobic reactor, the water quality adjustment chamber is provided with a second water quality measuring instrument, the water quality adjustment chamber introduces lye, and the phosphorus removal domestic sewage and the aerobic tank effluent are introduced to adjust the water quality of the water from step S21. The measured parameters of the second water quality measuring instrument include pH, COD, ORP, NH4 + , NO2 - , NO3 - and SO4 2- , and the water quality conditions are controlled as follows: the pH value is controlled between 6.8 and 8.3, the ORP is controlled between-150 mV and-300 mV, and then the effluent is discharged to the next step. Step S3, deep purification treatment, deeply removing residual pollutants in the water, the water is introduced into an anaerobic ammonia oxidation reactor inoculated with anaerobic ammonia oxidation bacteria, and nitrogen generated is recycled to the pyrite gas tank in the step S1.

2. The acid mine drainage advanced treatment method of claim 1, wherein, In the step S2, the sulfate-reducing bacteria reaction zone comprises a first unit, a second unit and a third unit, the pH value of the first unit is controlled to be equal to 3, the pH value of the second unit is controlled to be between 5 and 5.5, the pH value of the third unit is controlled to be between 7 and 7.8, and the temperature of the first unit, the second unit and the third unit is controlled to be 37℃, the ORP is lower than-150mV, the COD / SO4 2- is 0.6-0.9, and the HRT is 1-3d, wherein the generated pyrrhotite precipitate in the third unit is introduced into the step S1 for use.

3. The acid mine drainage advanced treatment method of claim 2, wherein, The first unit, the second unit and the third unit in the step S2 are double compartments, each comprising a front end compartment and a rear end compartment, each front end compartment is provided with a first water quality measuring instrument for parameter measurement, each front end compartment introduces sludge fermentation liquid and alkali liquid, and the amount of hydrogen sulfide generated in the step S1 and escaped by nitrogen blowing is controlled according to the parameter measurement result of the first water quality measuring instrument, when each parameter reaches the biological reaction requirement, the rear end compartment is introduced for biological reaction, and stirring is carried out at the same time, the parameter measurement of the first water quality measuring instrument includes pH, ORP, COD, SO4 2- and heavy metals.

4. The method for advanced treatment of acid mine drainage water according to claim 2, characterized in that, The volume number of sulfate-reducing bacteria inoculated sludge in the front-end compartment of the first unit of the multi-unit anaerobic reactor is controlled to be 0-50% of the effective volume of the reaction cavity; The volume number of sulfate-reducing bacteria inoculated sludge in the rear-end compartment of the first unit, the double-compartment of the second unit and the double-compartment of the third unit of the multi-unit anaerobic reactor is controlled to be 25%-50% of the effective volume of the reaction cavity; The volume number of anaerobic ammonia oxidation bacteria inoculated sludge in the anaerobic ammonia oxidation reactor is controlled to be 75%-90% of the effective volume of the reaction cavity.

5. The method for advanced treatment of acid mine drainage water according to claim 1, characterized in that, The matching method of introducing the main flow water including domestic sewage and effluent of the aerobic tank in the step S22 is as follows: Method one: if the molar ratio of NH4 + and SO4 2- in effluent is greater than 2, the effluent from aerobic tank is introduced, the molar ratio of excess NH4 + and NO3 - is controlled to be 1, and the carbon-nitrogen ratio of COD and NO3 - is controlled to be between 0.43 and 0.75; Method two: if the molar ratio of NH4 + and SO4 2- in effluent is equal to 2, the effluent from the aerobic tank is introduced, and the carbon-nitrogen ratio of COD and NO3 - is controlled between 1.07 and 1.

67. Method three: if the molar ratio of NH4 + and SO4 2- in effluent is less than 2, introduce phosphorus removal domestic sewage to control the molar ratio of NH4 + and SO4 2- to be 2, and introduce aerobic tank effluent to control the carbon-nitrogen ratio of COD and NO3 - to be between 1.07 and 1.

67.

6. The method for advanced treatment of acid mine drainage water according to claim 1, characterized in that, In the step S3, the internal environmental conditions of the anaerobic ammonia oxidation reactor are controlled as follows: the temperature is controlled to be 30-37℃, and the HRT is controlled to be 4-8h.

7. The method for advanced treatment of acid mine drainage water according to claim 2, characterized in that, The pyrite in the pyrite gas production tank in step S1 is from abandoned pyrite tailings in a surrounding mine or the pyrrhotite precipitate generated by the third unit of the multi-unit anaerobic reactor, and the particle size of the pyrite is controlled to be 50-200 mesh, and the pyrite is added when the ferrous ion generation rate is reduced for the second time, and the pyrite is fed from the solid inlet of the pyrite gas production tank.

Images