Combined advanced treatment device and method for acid mine drainage and municipal wastewater

Abstract

The application discloses a kind of acid mine drainage and urban sewage combined advanced treatment device and method, comprising: urban sewage storage area, homogeneous conditioning area, permeable reaction wall area and automation control area.The application couples and disposes acid mine drainage and urban sewage to achieve the purpose of "waste treatment with waste", simultaneously realizes the reduction and resource of acid mine drainage and urban sewage, has the significant advantages of low cost, high stability, efficient removal of multiple types of pollutants and waste resource allocation optimization and reuse, meets the sustainable development needs of water plant and permeable reaction wall technology, and is suitable for engineering popularization and application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of groundwater remediation, and relates to the treatment of acid mine drainage and municipal wastewater, in particular to a combined advanced treatment device and method for acid mine drainage and municipal wastewater. BACKGROUND

[0002] The development of mineral resources provides strong support for economic and social development, but mining activities have also caused ecological environmental problems to some extent, and acid mine drainage (AMD) is one of the most serious environmental problems. AMD is a kind of difficult-to-treat wastewater with low pH, high ferrous iron (Fe 2+ ) and sulfate (SO4 2- ) and coexistence of multiple heavy metal ions, which is generated by a series of chemical and biological oxidation processes when the main sulfide minerals of pyrite (FeS2) in coal mines or various non-ferrous mines are exposed to air and groundwater or surface water during mining activities or tailings stacking, and has the characteristics of wide pollution area, long pollution duration and serious harm degree.

[0003] At present, water quality neutralization method is generally used to treat AMD, and lime, limestone and other alkaline substances are used for treatment, and the process and technology are relatively simple, but this method has insufficient treatment depth, and a large amount of sludge is generated after neutralization, which is difficult to treat and is easy to cause secondary pollution to the environment; at the same time, the generation of AMD has a certain persistence, so the long-term operation cost is high.

[0004] In addition, sulfate reducing bacteria (SRB) is also used as the main working medium to treat AMD by biological method. SRB can reduce excess SO4 2- in AMD to hydrogen sulfide (H2S) by using organic matter or hydrogen (H2). The generated H2S is easy to combine with metals in AMD and precipitate as stable metal sulfides, which can be recycled and utilized again. However, the anaerobic degradation of SRB has the following major defects: 1) AMD lacks the electron donors required by SRB, such as organic matter, H2, etc.; 2) the metabolic product H2S of SRB is a highly toxic, corrosive and flammable gas with obvious odor, and the conversion of H2S to elemental sulfur (S) requires an additional oxidation stage; 3) SRB needs to form a symbiotic relationship with other microorganisms in the bioreactor; 4) SRB is sensitive to external environment, such as pH, temperature, hydraulic load and substrate load; 5) the biological degradation process of SRB is a multi-stage reaction, and the time required for complete mineralization of organic compounds is much longer than that of aerobic process; 6) the applicability and effectiveness of SRB are limited by the alkalinity production capacity of the system and the acidity of the water quality (or the acid production capacity of the wastewater). SUMMARY

[0005] To solve the above problems, the application provides a combined deep treatment device and method for acid mine wastewater and municipal wastewater, which couples and disposes the acid mine wastewater and the municipal wastewater to achieve the purpose of "waste treatment with waste", and simultaneously realizes the reduction and resource utilization of the acid mine wastewater and the municipal wastewater, has the advantages of low cost, high stability, efficient removal of multiple types of pollutants, optimal reuse of waste resources, and the like, meets the sustainable development needs of water plants and permeable reaction wall technology, and is suitable for engineering popularization and application.

[0006] To achieve the above purpose, the application adopts the following technical solutions:

[0007] The application provides a combined deep treatment device for acid mine wastewater and municipal wastewater, which comprises:

[0008] A municipal wastewater storage area for storing nitrate wastewater, waste lye and municipal domestic wastewater;

[0009] A homogenization adjustment area for uniformly mixing the acid mine wastewater and the nitrate wastewater, the waste lye and the municipal domestic wastewater;

[0010] A permeable reaction wall area for the collaborative purification of the acid mine wastewater and the municipal wastewater;

[0011] And an automatic control area for controlling the operation of the equipment of the municipal wastewater storage area.

[0012] The municipal wastewater storage area is provided with a first conveying pump, a second conveying pump and a third conveying pump and a plurality of water quality measuring instruments, and the first conveying pump, the second conveying pump and the third conveying pump are connected with the homogenization adjustment area respectively.

[0013] The homogenization adjustment area comprises a first homogenization adjustment pool and a second homogenization adjustment pool arranged adjacently.

[0014] The permeable reaction wall area comprises an anaerobic ammonia oxidation permeable reaction wall and a deep treatment permeable reaction wall arranged adjacently.

[0015] The second homogenization adjustment pool is arranged adjacently with the anaerobic ammonia oxidation permeable reaction wall.

[0016] As a preferred scheme of the present application, the municipal sewage storage area comprises a nitrate sewage storage tank, a waste lye storage tank and a municipal domestic sewage storage tank, the nitrate sewage storage tank is connected with the first homogenizing adjustment tank through the first delivery pump, the waste lye storage tank is connected with the second homogenizing adjustment tank through the second delivery pump, and the municipal domestic sewage storage tank is connected with the second homogenizing adjustment tank through the third delivery pump.

[0017] As a preferred scheme of the present application, the first homogenizing adjustment tank comprises a pebble wall and a first water distribution pipe, the pebble wall wraps the first water distribution pipe; the second homogenizing adjustment tank comprises a pebble wall and a second water distribution pipe, the pebble wall wraps the second water distribution pipe, and the first water distribution pipe and the second water distribution pipe are respectively provided with a water inlet pipe and a water distribution branch pipe; the first homogenizing adjustment tank is respectively provided with a first monitoring well and a second monitoring well at two ends.

[0018] As a preferred scheme of the present application, the water distribution branch pipe is provided with a water distribution opening, the water distribution openings are uniformly distributed and the opening direction is consistent with the seepage direction of the acid mine drainage pollution plume, and the axis of the water distribution opening and the horizontal direction form an angle of 45°.

[0019] As a preferred scheme of the present application, the anaerobic ammonia oxidation permeable reaction wall is respectively provided with a third monitoring well and a fourth monitoring well at two ends, and the advanced treatment permeable reaction wall is provided with a fifth monitoring well away from the homogenizing adjustment area.

[0020] As a preferred scheme of the present application, the automatic control area comprises a PLC and a computer, the PLC is provided with an interface and is connected with the first delivery pump, the second delivery pump, the third delivery pump and a plurality of water quality measuring instruments, and the PLC is connected with the computer to realize automatic control.

[0021] As a preferred scheme of the present application, the permeability coefficients of the first homogenizing adjustment tank, the second homogenizing adjustment tank, the anaerobic ammonia oxidation permeable reaction wall and the advanced treatment permeable reaction wall are more than 2 times of the permeability coefficient of the aquifer, and the permeability coefficients of the first homogenizing adjustment tank, the second homogenizing adjustment tank, the anaerobic ammonia oxidation permeable reaction wall and the advanced treatment permeable reaction wall are equal or gradually increase according to the seepage flow direction of the acid mine drainage pollution plume.

[0022] The present application also provides a combined advanced treatment method of acid mine drainage and municipal sewage by using the combined advanced treatment device.

[0023] As a preferred scheme of the present application, the treatment method comprises the following steps:

[0024] 1) The acid mine drainage is mixed with the nitrate wastewater to perform the first water quality adjustment: the nitrate wastewater is introduced into the first homogenizing adjustment tank to uniformly mix the nitrate wastewater and the acid mine drainage; the water quality of the effluent of the first homogenizing adjustment tank is determined, and the molar concentration ratio of total iron to nitrate in the acid mine drainage pollution plume flowing out of the first homogenizing adjustment tank is 2-6;

[0025] Sodium nitrate is the main raw material in the fields of enamel, glass, fertilizer, metallurgy, machinery, etc., and its demand in the market shows an increasing trend year by year. However, a considerable part of sodium nitrate exists in wastewater in the related use or production process, and direct discharge will cause water pollution. In addition, a large amount of pickling waste nitric acid will also be produced in the surface treatment process of stainless steel. At present, special treatment is needed for such nitrate wastewater, and the methods mainly include high-temperature calcination method, neutralization and recovery method, membrane filtration method, solvent extraction method, reduced pressure evaporation method, forced circulation evaporation, etc., all of which require a large treatment cost. In the present application, the nitrate wastewater is used to supplement nitrate for the acid mine drainage, and is jointly treated in the anaerobic ammonia oxidation permeable reaction wall.

[0026] 2) The acid mine drainage is mixed with the waste lye and the urban domestic wastewater to perform the second water quality adjustment: the waste lye and the urban domestic wastewater are introduced into the second homogenizing adjustment tank to uniformly mix the waste lye, the urban domestic wastewater and the acid mine drainage; the water quality of the effluent of the second homogenizing adjustment tank is determined, and the pH of the acid mine drainage pollution plume flowing out of the second homogenizing adjustment tank is 7.27-7.32, the molar concentration of ammonia nitrogen is 1 / 8-1 / 3 of the molar concentration of total iron and 2-8 times of the molar concentration of sulfate;

[0027] Hydrogen sulfide (H2S) is a toxic and irritating gas, which is commonly found in sewage treatment plants, steel mills, coking enterprises, chemical plants, oil fields and other industrial processes. Among them, the absorbent method is the main means for treating hydrogen sulfide, and the commonly used absorbents include ammonia water, calcium hydroxide solution and other alkaline liquids. The absorbent method will produce a large amount of sulfur-containing salt waste lye, and the current treatment methods include acid-base neutralization method, DTRO membrane concentration technology, hollow membrane + nanofiltration treatment process, etc., which require a large equipment investment and high operation cost, and a large treatment cost needs to be invested. In the present application, the waste lye is used to adjust the pH of the acid mine drainage, supplement ammonia nitrogen and remove heavy metals, and the urban domestic wastewater further supplements ammonia nitrogen and organic matter on the basis of the first ammonia nitrogen supplement by the waste lye to the acid mine drainage to meet the metabolic stoichiometry of anaerobic ammonia oxidation bacteria, and then is jointly treated in the anaerobic ammonia oxidation permeable reaction wall.

[0028] 3) Simultaneous denitrification, desulfurization and iron removal of acid mine drainage and municipal wastewater: the acid mine drainage pollution plume seeps into the anaerobic ammonium oxidation permeable reaction wall from the second homogenization adjustment tank, the medium is anaerobic ammonium oxidation biofilm or anaerobic ammonium oxidation granular sludge, the medium filling ratio is more than 75%, and the hydraulic retention time HRT is 4-8h;

[0029] Anaerobic ammonium oxidation (Anammox) process is an economic and efficient, environmentally friendly biological denitrification technology, which is particularly suitable for treating low-organic carbon and high-ammonia-nitrogen wastewater. The process relies on autotrophic Anammox bacteria, and under anoxic conditions, ammonia is used as the electron donor, and nitrite is used as the electron acceptor to generate nitrogen (N2) and part of nitrate (NH4 + +1.32NO2 - →N2+0.26NO3 - ). In recent years, research has found that Anammox bacteria have diverse metabolic pathways, in addition to the nitrite-type anaerobic ammonium oxidation reaction as described above, they can also occur sulfate-type anaerobic ammonium oxidation reaction, ferrous-type anaerobic ammonium oxidation reaction and iron ammonia oxidation reaction. Among them, the sulfate-type anaerobic ammonium oxidation is a biological reaction in which Anammox bacteria use ammonia as an electron donor and sulfate as an electron acceptor, and the reaction product is N2 and S (2NH4 + +SO4 2- →N2+S), the mixed wastewater of acid mine drainage and municipal wastewater flowing out of the homogenization adjustment zone in the present invention has the characteristics of low COD, high NH4 + and alkaline, which is very conducive to the occurrence of sulfate-type anaerobic ammonium oxidation reaction; the ferrous-type anaerobic ammonium oxidation is a biological reaction in which Anammox bacteria use Fe 2+ as an electron donor and (nitrate) as an electron acceptor, and the reaction product is N2 and trivalent iron (Fe 3+ )(NO3 - +5Fe 2+ →0.5N2+5Fe 3+ ), due to the adsorption and utilization of Anammox bacteria to Fe 3+ , the effluent Fe 3+ concentration is often below the detection limit; iron ammonia oxidation is a biological reaction in which Anammox bacteria use ammonia as an electron donor and Fe 3+ as an electron acceptor, and the reaction product is N2 and Fe 2+ (NH4 + +3Fe 3+ →0.5N2+3Fe 2+ ), due to the adsorption and utilization of Anammox bacteria to Fe 2+ , the effluent Fe 2+ concentration is often below the detection limit.

[0030] 4) The advanced treatment of acid mine drainage and municipal wastewater: the acid mine drainage pollution plume flowing out of the ANAMMOX PRB is infiltrated into the advanced treatment PRB with the modified bentonite and fly ash composite material as the medium, the hydraulic retention time (HRT) is 3-6h, and the effluent is re-infiltrated into the soil and then into the groundwater.

[0031] As a preferred scheme of the present application, in step 4), the preparation method of the modified bentonite and fly ash composite material is as follows: fly ash and calcium oxide with a mass ratio of 1:1 are calcined at a high temperature of 1200 DEG C for 3 hours, the temperature is lowered to 600 DEG C, bentonite is added in a volume ratio of 1:1-1:3 of fly ash and bentonite, and the calcination is continued for 1.5-2 hours to obtain the modified bentonite and fly ash composite material.

[0032] In the present application, fly ash is one of the industrial wastes with the largest discharge amount, and the annual discharge amount reaches nearly 160 million tons at present, however, the utilization rate is only about 50%, and a large amount of fly ash is stacked in ash fields, which not only occupies a large amount of land resources, but also easily causes environmental pollution. Fly ash, as a solid particle with porosity and large specific surface area, can be used as an adsorbent or coagulant in wastewater treatment, has the advantage of low price, has good adsorption effect between pH values of 4-7, the heavy metal adsorption rate can reach 80-90%, the organic matter removal rate can reach 60%, the removal rates of SS, total bacterial count and coliform group are more than 90%, and the removal of color and odor is particularly obvious. However, due to the low adsorption capacity of fly ash, the removal efficiency of pollutants is low. The modified bentonite and fly ash composite material by the calcination method can significantly improve the adsorption capacity and effect.

[0033] Compared with the prior art, the present application has the following beneficial effects:

[0034] The present application couples the disposal of acid mine drainage and municipal wastewater to achieve the purpose of "waste treatment with waste", and simultaneously realizes the reduction and resource utilization of acid mine drainage and municipal wastewater, has the advantages of low cost, high stability, high efficiency in removing multiple types of pollutants, optimal reuse of waste resources, and the like, meets the sustainable development needs of water plants and PRB technology, and is suitable for engineering popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a schematic diagram of the present application.

[0036] Figure 2 is a schematic diagram of the water distribution pipe of the present application.

[0037] Figure 3 is a schematic diagram of the water distribution branch pipe of the present application.

[0038] In the figure, 1. Urban sewage storage area; 1-1. Nitrate wastewater storage tank; 1-2. Waste lye storage tank; 1-3. Urban domestic sewage storage tank; 1-4. First delivery pump; 1-5. Second delivery pump; 1-6. Third delivery pump; 1-7. First water quality measuring instrument; 1-8. Second water quality measuring instrument; 1-9. Third water quality measuring instrument; 2. Homogeneous adjustment area; 2-1. First homogeneous adjustment tank; 2-2. Second homogeneous adjustment tank; 2-3. First monitoring well; 2-4. Second monitoring well; 2-5. Third monitoring well; 2-6. Gravel wall; 2-7. First water distribution pipe; 2-8. Second water distribution pipe; 2-9. Water inlet pipe; 2-10. Water distribution branch pipe; 2-11. Water distribution port; 2-12. Frame; 3. Permeable reaction wall area; 3-1. Anaerobic ammonia oxidation permeable reaction wall; 3-2. Advanced treatment permeable reaction wall; 3-3. Fourth monitoring well; 3-4. Fifth monitoring well; 4. Automatic control area; 4-1. PLC; 4-2. Computer; 5. Ground surface; 6. Aquiclude; 7. Water injection well; 8. Water pumping well; 9. Aquifer; 10. Groundwater level. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0040] Reference Figure 1 The present application provides a combined advanced treatment device and method for acid mine drainage and urban sewage, which comprises an urban sewage storage area 1, a homogeneous adjustment area 2, a permeable reaction wall area 3, and an automatic control area 4. The urban sewage storage area 1 is used to store nitrate wastewater, waste lye, and urban domestic sewage, to adjust the acid mine drainage, and to strengthen the growth and metabolism of anaerobic ammonia oxidation bacteria. The homogeneous adjustment area 2 comprises first and second homogeneous adjustment tanks 2-1 and 2-2 arranged adjacently, and is used to uniformly mix the acid mine drainage, the nitrate wastewater, the waste lye, and the urban domestic sewage. The first, second, and third delivery pumps 1-4, 1-5, and 1-6 are arranged between the urban sewage storage area 1 and the homogeneous adjustment area 2, and are used to pump the nitrate wastewater, the waste lye, and the urban domestic sewage into the homogeneous adjustment area 2 as needed. The permeable reaction wall area 3 is used for the collaborative advanced treatment of the acid mine drainage and the urban sewage, and comprises an anaerobic ammonia oxidation permeable reaction wall 3-1 using an anaerobic ammonia oxidation biofilm or an anaerobic ammonia oxidation granular sludge as a medium, and an advanced treatment permeable reaction wall 3-2 using a modified bentonite and fly ash composite material as a medium. The automatic control area 4 is used to realize the intelligent operation of the equipment in the urban sewage storage area 1.

[0041] The urban sewage storage area 1 comprises a nitrate sewage storage tank 1-1, a waste lye storage tank 1-2 and an urban domestic sewage storage tank 1-3. The nitrate sewage storage tank 1-1 is connected with the first homogenizing adjustment tank 2-1 through the first delivery pump 1-4. The waste lye storage tank 1-2 is connected with the second homogenizing adjustment tank 2-2 through the second delivery pump 1-5. The urban domestic sewage storage tank 1-3 is connected with the second homogenizing adjustment tank 2-2 through the third delivery pump 1-6.

[0042] The nitrate sewage storage tank 1-1 is provided with a first water quality measuring instrument 1-7. The waste lye storage tank 1-2 is provided with a second water quality measuring instrument 1-8. The urban domestic sewage storage tank 1-3 is provided with a third water quality measuring instrument 1-9.

[0043] The first homogenizing adjustment tank 2-1 comprises a pebble wall 2-6 and a first water distribution pipe 2-7. The pebble wall 2-6 wraps the first water distribution pipe 2-7. The second homogenizing adjustment tank 2-2 comprises a pebble wall 2-6 and a second water distribution pipe 2-8. The pebble wall 2-6 wraps the second water distribution pipe 2-8.

[0044] The homogenizing adjustment area 2 and the permeable reaction wall area 3 are arranged between the aquiclude 6 and the ground surface 5.

[0045] Referring to Figure 2 and Figure 3 The first water distribution pipe 2-7 and the second water distribution pipe 2-8 are both provided with an inlet pipe 2-9 and a water distribution branch pipe 2-10. The inlet pipe 2-9 is arranged at the center of the frame 2-12 of the first water distribution pipe 2-7 or the second water distribution pipe 2-8. The water distribution branch pipe 2-10 is uniformly arranged on the inlet pipe 2-9. The water distribution branch pipe 2-10 is provided with a plurality of water distribution openings 2-11. The water distribution openings 2-11 are uniformly distributed and the opening direction is consistent with the seepage direction of the acid mine drainage pollution plume. The axis of the water distribution opening 2-11 forms a 45° angle with the horizontal direction.

[0046] The first homogenizing adjustment tank 2-1 is respectively provided with a first monitoring well 2-3 and a second monitoring well 2-4 at two ends. The anaerobic ammonia oxidation permeable reaction wall 3-1 is respectively provided with a third monitoring well 2-5 and a fourth monitoring well 3-3 at two ends. The advanced treatment permeable reaction wall 3-2 is provided with a fifth monitoring well 3-4 away from the homogenizing adjustment area 2.

[0047] That is, the arrangement sequence of the homogenizing adjustment area 2 and the permeable reaction wall area 3 is: the first monitoring well 2-3, the first homogenizing adjustment tank 2-1, the second monitoring well 2-4, the second homogenizing adjustment tank 2-2, the third monitoring well 2-5, the anaerobic ammonia oxidation permeable reaction wall 3-1, the fourth monitoring well 3-3, the advanced treatment permeable reaction wall 3-2 and the fifth monitoring well 3-4.

[0048] The permeability coefficients of the first homogenization adjustment tank 2-1, the second homogenization adjustment tank 2-2, the anaerobic ammonia oxidation permeable reaction wall 3-1, and the deep treatment permeable reaction wall 3-2 are 2 times or more than the permeability coefficient of the aquifer, and the permeability coefficients of the first homogenization adjustment tank 2-1, the second homogenization adjustment tank 2-2, the anaerobic ammonia oxidation permeable reaction wall 3-1, and the deep treatment permeable reaction wall 3-2 are equal or gradually increase according to the seepage flow direction of the acid mine drainage pollution plume.

[0049] The water injection well 7 and the water pumping well 8 are arranged at the front end of the homogenization adjustment area 2 and embedded in the aquifer 9 below the ground surface 5, which is used to prevent the groundwater level 10 from fluctuating greatly and ensure the constant hydraulic retention time (HRT) of the permeable reaction wall area 3.

[0050] The medium of the anaerobic ammonia oxidation permeable reaction wall 3-1 is an anaerobic ammonia oxidation biofilm or anaerobic ammonia oxidation granular sludge, which is used to simultaneously remove ammonia nitrogen, nitrate, sulfate, ferrous iron, and ferric iron in acid mine drainage and municipal sewage; the medium of the deep treatment permeable reaction wall 3-2 is a modified bentonite and fly ash composite material, which is used to remove unreacted pollutants in the seepage flow of the acid mine drainage pollution plume. Both the anaerobic ammonia oxidation permeable reaction wall 3-1 and the deep treatment permeable reaction wall 3-2 are internally provided with a steel support, the top of the steel support is provided with a hoisting structure, and the steel support is externally coated with a water-permeable geotextile, and the overlap width of the geotextile is not less than 200 mm.

[0051] The modified bentonite and fly ash composite material is obtained by calcining fly ash and calcium oxide at a mass ratio of 1:1 at 1200°C for 3 hours, then cooling to 600°C, adding bentonite at a volume ratio of fly ash to bentonite of 1:1-1:3, and continuing to calcine for 1.5-2 hours.

[0052] The automatic control area 4 includes a PLC 4-1 and a computer 4-2, the PLC 4-1 is internally provided with an interface and is connected to the first delivery pump 1-4, the second delivery pump 1-5, and the third delivery pump 1-6, as well as the first water quality tester 1-7, the second water quality tester 1-8, and the third water quality tester 1-9, the PLC 4-1 is connected to the computer 4-2 for automatic control, which is used to realize the intelligent operation of the equipment in the municipal sewage storage area 1.

[0053] Embodiment

[0054] The embodiment provides a method for treating acid mine drainage and municipal sewage by using a combined deep treatment device:

[0055] (a) mixing acid mine drainage with nitrate sewage for the first water quality adjustment

[0056] The total iron concentration in the acid mine drainage determined according to the first monitoring well 2-3, the nitrate wastewater is pumped from the nitrate wastewater storage tank 1-1 by the first delivery pump 1-4 into the first homogeneous conditioning tank 2-1 as needed, so that the nitrate wastewater and the acid mine drainage are uniformly mixed; the water quality of the effluent from the first homogeneous conditioning tank 2-1 is determined by the second monitoring well 2-4, and the molar concentration ratio of total iron and nitrate in the acid mine drainage pollution plume seepage flowing out of the first homogeneous conditioning tank 2-1 is 2-6.

[0057] (b) The acid mine drainage is mixed with waste lye and municipal sewage for the second water quality conditioning

[0058] The pH of the acid mine drainage determined according to the second monitoring well 2-4, the waste lye is pumped from the waste lye storage tank 1-2 by the second delivery pump 1-5 into the second homogeneous conditioning tank 2-2 as needed, and the municipal sewage is pumped from the municipal sewage storage tank 1-3 by the third delivery pump 1-6 into the second homogeneous conditioning tank 2-2 as needed, so that the waste lye and the municipal sewage are uniformly mixed with the acid mine drainage; the water quality of the effluent from the second homogeneous conditioning tank 2-2 is determined by the third monitoring well 2-5, and the pH of the acid mine drainage pollution plume seepage flowing out of the second homogeneous conditioning tank 2-2 is 7.27-7.32, the molar concentration of ammonia nitrogen is 1 / 8-1 / 3 of the molar concentration of total iron and 2-8 times the molar concentration of sulfate.

[0059] c、Synchronous denitrification, desulfurization and iron removal of acid mine drainage and municipal sewage

[0060] The acid mine drainage pollution plume seepage flowing out of the second homogeneous conditioning tank 2-2 enters the anaerobic ammonia oxidation permeable reaction wall 3-1 with anaerobic ammonia oxidation biofilm or anaerobic ammonia oxidation granular sludge as the medium, the medium filling ratio is more than 75%, and the hydraulic retention time HRT is controlled at 4-8h. The anaerobic ammonia oxidation biofilm or anaerobic ammonia oxidation granular sludge is pre-cultured before being put in, and the pre-culturing conditions, including the concentrations of sulfate, total iron, ammonia nitrogen and nitrate, and pH, are all enlarged by 5%-15% based on the benchmarks of the relevant indicators of the mixed wastewater composed of the acid mine drainage and the municipal sewage.

[0061] The anaerobic ammonia oxidation bacteria remove the nitrate nitrogen in the nitrate wastewater and the ferrous iron in the acid mine drainage through the ferrous-type anaerobic ammonia oxidation reaction, and remove the ammonia nitrogen in the waste lye and the municipal sewage, and the sulfate and ferric iron in the acid mine drainage through the sulfate-type anaerobic ammonia oxidation reaction and the iron ammonia oxidation reaction, and the metabolic products of the above two iron-related reactions, ferrous iron and ferric iron, can be further biologically utilized by the anaerobic ammonia oxidation bacteria to strengthen their growth and metabolism, and thus the acid mine drainage and the municipal sewage can be jointly treated to achieve synchronous denitrification, desulfurization and iron removal.

[0062] The water quality of the anaerobic ammonia oxidation permeable reaction wall 3-1 is determined through the fourth monitoring well 3-3, and then the biological activity of the anaerobic ammonia oxidation bacteria can be immediately mastered, so that long-term substrate inhibition leading to complete inactivation of the anaerobic ammonia oxidation bacteria can be avoided.

[0063] d, advanced treatment of acid mine drainage and municipal wastewater

[0064] The acid mine drainage pollution plume seepage flowing out of the anaerobic ammonia oxidation permeable reaction wall 3-1 continues to flow through the advanced treatment permeable reaction wall 3-2 with a medium of modified bentonite and fly ash composite, and the hydraulic retention time HRT is controlled at 3-6h, for removing the remaining unreacted pollutants in the acid mine drainage and municipal wastewater pollution plume seepage, and then the water can re-enter the underground soil and flow into the groundwater; at the same time, the water quality of the advanced treatment permeable reaction wall 3-2 is determined through the fifth monitoring well 3-4, and the operation of the advanced treatment permeable reaction wall 3-2 can be simply and conveniently mastered through real-time monitoring of the water quality, and when the water quality is not good, the fault part can be found in time and the replacement of the failed or improper medium can be immediately carried out.

[0065] The above is only a preferred embodiment of the present application, and is not any form and substantial limitation of the present application. It should be noted that, for ordinary skilled persons in the art, without departing from the method of the present application, some improvements and supplements can be made, and these improvements and supplements should be considered as the protection range of the present application. For those skilled in the art, without departing from the spirit and scope of the present application, some changes, modifications and equivalent changes of the above disclosed technical content can be made, which are equivalent embodiments of the present application; at the same time, any equivalent change, modification and evolution of the above-mentioned embodiments according to the essential technology of the present application are still within the scope of the technical solutions of the present application.

Claims

1. A method for combined advanced treatment of acid mine drainage and municipal wastewater, characterized in that, The treatment method comprises the following steps: 1) the first water quality adjustment of mixing acid mine drainage with nitrate sewage: the nitrate sewage is introduced into the first homogenizing adjustment tank to uniformly mix the nitrate sewage and the acid mine drainage; the water quality of the effluent of the first homogenizing adjustment tank is determined, and the molar concentration ratio of total iron and nitrate in the acid mine drainage pollution plume flowing out of the first homogenizing adjustment tank is 2-6; 2) the second water quality adjustment of mixing the acid mine drainage with waste lye and urban domestic sewage: the waste lye and the urban domestic sewage are introduced into the second homogenizing adjustment tank to uniformly mix the waste lye, the urban domestic sewage and the acid mine drainage; the water quality of the effluent of the second homogenizing adjustment tank is determined, the pH of the acid mine drainage pollution plume flowing out of the second homogenizing adjustment tank is 7.27-7.32, the molar concentration of ammonia nitrogen is 1 / 3-1 / 8 of the molar concentration of total iron and 2-8 times of the molar concentration of sulfate; 3) the simultaneous denitrification, desulfurization and iron removal of the acid mine drainage and the urban sewage: the acid mine drainage pollution plume flowing out of the second homogenizing adjustment tank enters the anaerobic ammonium oxidation permeable reaction wall, the medium is anaerobic ammonium oxidation biofilm or anaerobic ammonium oxidation granular sludge, the medium filling ratio is more than 75%, and the hydraulic retention time HRT is 4-8h; 4) the advanced treatment of the acid mine drainage and the urban sewage: the acid mine drainage pollution plume flowing out of the anaerobic ammonium oxidation permeable reaction wall enters the advanced treatment permeable reaction wall with modified bentonite and fly ash composite material as the medium, the hydraulic retention time HRT is 3-6h, and the effluent reenters the underground soil and flows into the underground water.

2. The method according to claim 1, wherein the method is characterized by, In step 4), the preparation method of the modified bentonite and fly ash composite material is as follows: fly ash and calcium oxide with a mass ratio of 1:1 are calcined at 1200℃ for 3 hours, cooled to 600℃, bentonite is added in a volume ratio of 1:1-1:3 of fly ash and bentonite, and then calcined for 1.5-2 hours to obtain the modified bentonite and fly ash composite material.

3. The method for combined advanced treatment of acid mine drainage and municipal wastewater according to claim 1, characterized in that, The device used in the combined advanced treatment method comprises: a urban sewage storage area for storing nitrate sewage, waste lye and urban domestic sewage; a homogenizing adjustment area for uniformly mixing the acid mine drainage and the nitrate sewage, the waste lye and the urban domestic sewage; a permeable reaction wall area for the collaborative purification of the acid mine drainage and the urban sewage; and an automatic control area for controlling the operation of the equipment of the urban sewage storage area; wherein the urban sewage storage area is provided with a first conveying pump, a second conveying pump and a third conveying pump and a plurality of water quality determinators, and the first conveying pump, the second conveying pump and the third conveying pump are connected with the homogenizing adjustment area respectively; the homogenizing adjustment area comprises a first homogenizing adjustment tank and a second homogenizing adjustment tank arranged adjacently; the permeable reaction wall area comprises an anaerobic ammonium oxidation permeable reaction wall and an advanced treatment permeable reaction wall arranged adjacently; the second homogenizing adjustment tank is arranged adjacently with the anaerobic ammonium oxidation permeable reaction wall.

4. The method for combined advanced treatment of acid mine drainage and municipal wastewater according to claim 3, characterized in that, The urban sewage storage area comprises a nitrate sewage storage tank, a waste lye storage tank and an urban domestic sewage storage tank, the nitrate sewage storage tank is connected with the first homogenizing adjustment tank through the first delivery pump, the waste lye storage tank is connected with the second homogenizing adjustment tank through the second delivery pump, and the urban domestic sewage storage tank is connected with the second homogenizing adjustment tank through the third delivery pump.

5. The method for combined advanced treatment of acid mine drainage and municipal wastewater according to claim 3, characterized in that, The first homogenizing adjustment tank comprises a pebble wall and a first water distribution pipe, the pebble wall wraps the first water distribution pipe; the second homogenizing adjustment tank comprises a pebble wall and a second water distribution pipe, the pebble wall wraps the second water distribution pipe, and the first water distribution pipe and the second water distribution pipe are respectively provided with a water inlet pipe and a water distribution branch pipe; the first homogenizing adjustment tank is respectively provided with a first monitoring well and a second monitoring well at two ends.

6. The method for combined advanced treatment of acid mine drainage and municipal wastewater according to claim 5, characterized in that, The water distribution branch pipe is provided with a water distribution opening, the water distribution openings are uniformly distributed and have the same opening direction as the seepage direction of the acid mine drainage pollution plume, and the axis of the water distribution opening forms a 45° angle with the horizontal direction.

7. The method according to claim 3, wherein the method is characterized by, The anaerobic ammonia oxidation permeable reaction wall is respectively provided with a third monitoring well and a fourth monitoring well at two ends, and the deep treatment permeable reaction wall is provided with a fifth monitoring well away from the homogenizing adjustment area.

8. The method for combined advanced treatment of acid mine drainage and municipal wastewater according to claim 3, characterized in that, The automatic control area comprises a PLC and a computer, the PLC is provided with an internal interface and is connected with the first delivery pump, the second delivery pump, the third delivery pump and a plurality of water quality measuring instruments, and the PLC is connected with the computer to realize automatic control.

9. The method for combined advanced treatment of acid mine drainage and municipal wastewater according to any one of claims 3 to 8, characterized in that, The permeability coefficients of the first homogenizing adjustment tank, the second homogenizing adjustment tank, the anaerobic ammonia oxidation permeable reaction wall and the deep treatment permeable reaction wall are more than twice the permeability coefficient of the aquifer, and the permeability coefficients of the first homogenizing adjustment tank, the second homogenizing adjustment tank, the anaerobic ammonia oxidation permeable reaction wall and the deep treatment permeable reaction wall are equal or gradually increase according to the seepage direction of the acid mine drainage pollution plume.

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