Internal circulation system and treatment method for treating acidic wastewater using SRB

Abstract

This invention discloses an internal circulation system and method for treating acidic wastewater using SRB (Self-Retaining Bioreactor), relating to the field of wastewater treatment technology. The internal circulation system for treating acidic wastewater using SRB includes a mixer, a physicochemical processor, and an SRB membrane reactor. The mixer is used to mix the acidic wastewater to be treated with H2S, and has a first discharge port for discharging the H2S-containing acidic wastewater. The physicochemical processor, from bottom to top, includes a second inlet connected to the first discharge port, a first sedimentation layer, an Fe filter layer, a second sedimentation layer, and a second discharge port, arranged sequentially. The SRB membrane reactor, from bottom to top, includes a third inlet connected to the second discharge port, an SRB membrane reaction zone, and a third discharge port, arranged sequentially. The technical solution provided by this invention can effectively remove heavy metals and SO4 from acidic wastewater from mines. 2‑ Furthermore, it requires no external chemical reagents and has low operating costs.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to an internal circulation system and treatment method for treating acidic wastewater using SRB. Background Technology

[0002] Acidic mine wastewater (AMD) is highly acidic, with a pH value generally ranging from 1 to 4, and contains high concentrations (approximately 2–800 mg / L) of various metal ions, such as Fe. 2+ Cu 2+ Pb 2+ And contains a high amount of SO4. 2- The concentration of particulate matter (AMD) can reach as high as 1000 mg / L, while the organic matter content is extremely low, usually below 10 mg / L. If AMD wastewater is not effectively treated, it will enter surface water with surface runoff and even seep into the soil, causing environmental damage.

[0003] Currently, the commonly used treatment methods for AMD wastewater are: (1) Neutralization method, such as adding lime to adjust the pH of the wastewater to 6-9, and heavy metals will form hydroxide precipitates and be removed; (2) Adsorption method, such as using fly ash to adsorb and remove heavy metals in AMD wastewater; (3) Sulfide precipitation method, such as adding sodium sulfide to form sulfide precipitates with heavy metals; (4) Membrane separation method, such as using nanofiltration membranes / reverse osmosis membranes to separate heavy metals in AMD wastewater by pressurized filtration.

[0004] However, the above treatment methods require the consumption of large amounts of chemical reagents or regular replacement of adsorbent / membrane materials, have poor operating conditions, high energy consumption, and high operating costs, and are also ineffective for high concentrations of SO4 in wastewater. 2- Without effective removal, large amounts of SO4 remained. 2- Continuous intrusion into water bodies can lead to blackening and foul odor. Summary of the Invention

[0005] The main objective of this invention is to propose an internal circulation system and method for treating acidic wastewater using SRB (Self-Retaining Biosorbent Assay), aiming to solve the problems of existing methods for treating acidic mine wastewater, which require the consumption of large amounts of chemical reagents or regular replacement of adsorbent materials, and are ineffective in removing SO4. 2- The problem.

[0006] To achieve the above objectives, this invention proposes an internal circulation system for treating acidic wastewater using SRB, comprising:

[0007] A mixer for mixing acidic wastewater to be treated with H2S, the mixer having a first drain outlet for discharging the acidic wastewater containing H2S.

[0008] The physical and chemical processor includes, from bottom to top, a second inlet connected to the first outlet, a first sedimentation layer, an Fe filter layer, a second sedimentation layer, and a second outlet, which are sequentially arranged and connected to the first outlet.

[0009] The SRB membrane reactor includes, from bottom to top, a third inlet connected to the second drain outlet, an SRB membrane reaction zone, and a third drain outlet, arranged sequentially.

[0010] In one embodiment, the mixer has a first liquid inlet, a first air inlet, and a mixing chamber communicating with the first liquid inlet and the first air inlet, and a first drain outlet communicating with the mixing chamber; and / or,

[0011] The SRB membrane reactor further includes a second exhaust port disposed above the SRB membrane reaction zone, and the second exhaust port is connected to the first air inlet.

[0012] In one embodiment, the SRB membrane reactor further includes a gas collection chamber disposed adjacent to the second exhaust port.

[0013] In one embodiment, the SRB membrane reactor further includes a second three-phase separation zone disposed between the SRB membrane reaction zone and the gas collection chamber; and / or,

[0014] The physical and chemical processor also includes a first three-phase separation zone disposed between the second precipitate layer and the second drain outlet.

[0015] In one embodiment, the internal circulation system for treating acidic wastewater using SRB further includes a membrane gas supply system, which includes a gas collection tank.

[0016] The physicalization processor also includes a first exhaust port disposed above the second precipitation layer;

[0017] The SRB membrane reactor also includes a fourth air inlet corresponding to the SRB membrane reaction zone;

[0018] The first exhaust port is connected to the inlet pipe of the gas collecting tank, and the fourth inlet port is connected to the outlet pipe of the gas collecting tank; and / or,

[0019] The internal circulation system for treating acidic wastewater using SRB also includes an aeration system, which includes a dissolved air tank.

[0020] The SRB membrane reactor also includes a supernatant discharge pipe corresponding to the third discharge port;

[0021] The gas inlet pipe of the dissolved gas tank is connected to the first exhaust port, the liquid inlet of the dissolved gas tank is connected to the supernatant discharge pipe, and the exhaust port of the dissolved gas tank is provided with a first exhaust pipe extending into the bottom of the physicochemical processor and a second exhaust pipe extending into the bottom of the SRB membrane reactor.

[0022] In one embodiment, the gas collecting tank includes a first gas collecting tank and a second gas collecting tank. The first gas collecting tank is provided with a first inlet pipe at its inlet and a first outlet pipe at its outlet.

[0023] The second gas collecting tank is provided with a second air inlet pipe at the air inlet and a second air outlet pipe at the air outlet.

[0024] Valves are installed on the first air inlet pipe, the first air outlet pipe, the second air inlet pipe, and the second air outlet pipe.

[0025] In one embodiment, the aeration system further includes a first aeration pipe disposed below the second liquid inlet, wherein the air inlet end of the first aeration pipe is connected to the first exhaust pipe.

[0026] The SRB membrane reactor also includes a second aeration pipe disposed below the third inlet, the inlet end of the second aeration pipe being connected to the second exhaust pipe.

[0027] In one embodiment, the first precipitation layer includes a plurality of parallel first inclined tubes, the length of the first inclined tubes being 1 to 1.5 m, the horizontal inclination angle of the first inclined tubes being 30 to 60°, and the inner diameter of the first inclined tubes being 35 to 80 mm; and / or,

[0028] The Fe filter layer includes a lower support mesh, an upper support mesh, and iron-containing particles disposed between the lower support mesh and the upper support mesh; and / or

[0029] The second sedimentation layer includes a plurality of parallel inclined tubes, the length of which is 1 to 1.5 m, the horizontal inclination angle of which is 30 to 60°, and the inner diameter of which is 35 to 80 mm.

[0030] In one embodiment, the internal circulation system for treating acidic wastewater using SRB further includes a sludge concentrate recovery system, which includes a sludge pump.

[0031] The physical and chemical processor also includes a first mud hopper disposed below the second liquid inlet, and a first mud discharge pipe is provided at the bottom of the first mud hopper;

[0032] The SRB membrane reactor also includes a second sludge hopper located below the third inlet, and a second sludge discharge pipe is provided at the bottom of the second sludge hopper.

[0033] Both the first sludge discharge pipe and the second sludge discharge pipe are connected to the inlet of the sludge pump.

[0034] The present invention also proposes a method for treating acidic wastewater using any of the above-described internal circulation systems for treating acidic wastewater with SRB.

[0035] The technical solution of this invention employs a mixer to mix the acidic mine wastewater (AMD) to be treated with H2S gas, forming an acidic mine wastewater containing H2S. This H2S-containing wastewater is discharged from the mixer through a first drain outlet. The first drain outlet is connected to a second inlet via a pipeline. The H2S-containing wastewater enters a physicochemical processor through the second inlet. Inside the physicochemical processor, heavy metals in the acidic mine wastewater react with H2S to form sulfide precipitates. After the precipitation reaction, the wastewater level rises within the physicochemical processor, reaching the first precipitation layer. This first precipitation layer causes the sulfide precipitates to slide down to the bottom of the physicochemical processor. The wastewater level continues to rise, reaching the Fe filter layer. The Fe filter layer removes H2S from the wastewater... + The generation of H2 and the Fe filter layer also cause some heavy metals in the wastewater to precipitate, and the Fe naturally present in the wastewater... 2+ And the Fe newly generated by the above reaction 2+ It can consume a large amount of O2 in the wastewater and generate Fe. 3+ H in wastewater + The wastewater is consumed in large quantities, causing its pH value to approach neutral. At this point, heavy metal ions in the wastewater react with OH-. - When the ion concentration product exceeds its solubility product, heavy metal precipitation begins. After treatment with an Fe filter layer, some heavy metals in the wastewater further precipitate, consuming a large amount of H₂. + It also generates a large amount of H2. As the wastewater level rises to the second sedimentation layer, the sediment slides down under the action of the second sedimentation layer. The upward-flowing H2 can wash the second sedimentation layer, causing the sediment attached to the second sedimentation layer to slide down to the bottom of the physical and chemical processor.

[0036] After treatment by the physicochemical processor, the pH of the acidic mine wastewater is adjusted to 6-7. O2 in the wastewater is largely consumed, and most heavy metals are reacted and consumed. Sediment or suspended solids are primarily retained at the bottom of the processor, forming a sludge layer. The treated wastewater flows out through a second drain outlet, which is connected to a third inlet via a pipe. The second drain outlet is located above the third inlet. The wastewater from the second drain outlet flows into the SRB membrane reactor through the third inlet, raising the water level to the SRB membrane reaction zone. This zone is inoculated with SRB (sulfate-reducing bacteria). Because the wastewater has a near-neutral pH and is anaerobic, it is suitable for SRB survival. Furthermore, the low concentration of heavy metals eliminates their toxicity to the SRB bacteria. The SRB growing on the membrane in the reaction zone can remove SO42- in the wastewater. 2- It is reduced to H2S, and H2S can react with residual heavy metals (such as Cu) in wastewater. 2+ Pb 2+ The reaction (etc.) forms metal sulfide precipitates. The precipitates fall to the bottom of the SRB membrane reactor under gravity, forming a sludge layer. After further treatment by the SRB membrane reactor, the acidic mine wastewater meets the discharge standards and can be discharged through the third drain outlet.

[0037] The technical solution of this invention can effectively remove heavy metals from acidic mine wastewater, and SO4 2- It can also be effectively removed. Microbial treatment of acidic mine wastewater does not require the addition of external chemical agents and has low operating costs. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of an embodiment of the internal circulation system for treating acidic wastewater using SRB provided by the present invention.

[0040] Explanation of icon numbers:

[0041] 100. Internal circulation system for treating acidic wastewater; 1. Mixer; 11. First inlet; 12. First air inlet; 13. First outlet; 14. Water pump; 2. Physicochemical processor; 2a. First shell; 21. Second inlet; 22. First sedimentation layer; 221. First inclined tube; 23. Fe filter layer; 231. Iron-containing particles; 24. Second sedimentation layer; 241. Second inclined tube; 25. First three-phase separation zone; 26. Second outlet; 27. First exhaust port; 28. First aeration pipe; 29. ​​First exhaust pipe; 210. First sludge hopper; 211. First sludge discharge pipe; 212. Eighth valve; 213. H2 discharge main pipe; 3. SRB membrane reactor; 3a. Second shell; 31. Third inlet; 32. SRB membrane reaction zone; 33. Second three-phase separation zone; Phase separation zone; 34. Third drain outlet; 35. Gas collection chamber; 36. Second exhaust outlet; 37. Second aeration pipe; 38. Second exhaust pipe; 39. Second sludge hopper; 310. Second sludge discharge pipe; 311. Ninth valve; 312. Supernatant discharge pipe; 313. Second valve; 314. Pressure pump; 315. Fourth air inlet; 4. Dissolved gas tank; 41. Air inlet pipe of dissolved gas tank; 42. Liquid inlet of dissolved gas tank; 43. Dissolved gas discharge main pipe; 44. Third valve; 45. First valve; 51. First gas collection tank; 511. First air inlet pipe; 512. First air outlet pipe; 513. Fourth valve; 514. Fifth valve; 52. Second gas collection tank; 521. Second air inlet pipe; 522. Second air outlet pipe; 523. Sixth valve; 524. Seventh valve; 6. Sludge pump.

[0042] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0044] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0045] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0046] Currently, the commonly used treatment methods for AMD wastewater are: (1) Neutralization method, such as adding lime to adjust the pH of the wastewater to 6-9, and heavy metals will form hydroxide precipitates and be removed; (2) Adsorption method, such as using fly ash to adsorb and remove heavy metals in AMD wastewater; (3) Sulfide precipitation method, such as adding sodium sulfide to form sulfide precipitates with heavy metals; (4) Membrane separation method, such as using nanofiltration membranes / reverse osmosis membranes to separate heavy metals in AMD wastewater by pressurized filtration.

[0047] However, the above treatment methods require the consumption of large amounts of chemical reagents or regular replacement of adsorbent / membrane materials, have poor operating conditions, high energy consumption, and high operating costs, and are also ineffective for high concentrations of SO4 in wastewater. 2- Without effective removal, large amounts of SO4 remained. 2- Continuous intrusion into water bodies can lead to blackening and foul odor.

[0048] In view of this, the present invention proposes an internal circulation system for treating acidic wastewater using SRB, aiming to solve the problems of existing methods for treating acidic wastewater in mines, which require the consumption of large amounts of chemical reagents or regular replacement of adsorbent materials, and cannot effectively remove SO4. 2- The problem.

[0049] Please see Figure 1 In one embodiment of the present invention, the internal circulation system 100 for treating acidic wastewater using SRB includes:

[0050] Mixer 1, the mixer 1 being used to mix acidic wastewater to be treated with H2S, the mixer 1 having a first drain outlet 13 for discharging acidic wastewater containing H2S;

[0051] The physical and chemical processor 2 includes, from bottom to top, a second inlet 21 connected to the first outlet 13, a first sedimentation layer 22, an Fe filter layer 23, a second sedimentation layer 24, and a second outlet 26, which are sequentially arranged.

[0052] The SRB membrane reactor 3 includes, from bottom to top, a third inlet 31 connected to the second outlet 26, an SRB membrane reaction zone 32, and a third outlet 34, which are arranged sequentially.

[0053] The technical solution of this invention uses a mixer 1 to mix the acidic mine wastewater (AMD) to be treated with H2S gas, forming an acidic mine wastewater containing H2S. The H2S-containing acidic mine wastewater is discharged from the mixer 1 through a first drain port 13. The first drain port 13 is connected to a second inlet port 21 via a pipeline. The H2S-containing acidic mine wastewater enters a physicochemical processor 2 through the second inlet port 21. In the physicochemical processor 2, the heavy metals in the acidic mine wastewater react with H2S to form sulfide precipitates, with Pb as the precipitate. 2+ For example, the reaction formula is: Pb 2+ +H₂S→PbS↓+2H + Other heavy metals can react with H2S to form sulfide precipitates, and the reaction formula is the same as that of Pb. 2+ Similarly, and not all will be listed here; after the precipitation reaction occurs, the wastewater level rises within the physicochemical processor 2, reaching the first sedimentation layer 22. The first sedimentation layer 22 causes the sulfide precipitates to slide down to the bottom of the physicochemical processor 2. The wastewater level continues to rise, reaching the Fe filter layer 23. The Fe filter layer 23 causes the H in the wastewater to... + H2 is generated; the reaction is: Fe + 2H+ + →Fe 2+ +H2↑; In addition, when H in the wastewater + When the wastewater pH is close to neutral and is largely consumed, the Fe filter layer 23 also causes some heavy metals in the wastewater to precipitate, with Cu being the most abundant. 2+ For example, the reaction formula is: Fe + Cu 2+ →Cu↓+Fe 2+ Fe naturally present in wastewater 2+ And the Fe newly generated by the above reaction 2+ It can consume a large amount of O2 in the wastewater and generate Fe. 3+ The reaction formula is: 4Fe 2+ +O2+4H + →4Fe 3+ + 2H₂O, H₂ in wastewater + After being consumed in large quantities, the pH value of the wastewater approaches neutral. At this point, heavy metal ions in the wastewater react with OH-. -When the concentration product of the ions exceeds their solubility product, heavy metal precipitates begin to form, such as Fe(OH)3 precipitate. The reaction formula is: Fe 3+ +3OH - →Fe(OH)3↓. After treatment by Fe filter layer 23, some heavy metals in the wastewater further form precipitates, consuming a large amount of H₂. + The wastewater generates a large amount of H2. As the wastewater level rises to the second sedimentation layer 24, the sediment slides down under the action of the second sedimentation layer 24. The upward-flowing H2 can flush the second sedimentation layer 24, causing the sediment attached to the second sedimentation layer 24 to slide down to the bottom of the physical and chemical processor 2.

[0054] After treatment by the physicochemical processor 2, the pH of the acidic mine wastewater is adjusted to 6-7. O2 in the wastewater is largely consumed, and most heavy metals are reacted and consumed. Sediment or suspended solids are mostly retained at the bottom of the physicochemical processor 2, forming a sludge layer. The wastewater treated by the physicochemical processor 2 flows out through the second drain outlet 26, which is connected to the third inlet via a pipe and is located above the third inlet. The wastewater flowing from the second drain outlet 26 flows into the SRB membrane reactor through the third inlet, raising the wastewater level to the SRB membrane reaction zone. The SRB membrane reaction zone is inoculated with SRB (sulfate-reducing bacteria). Because the wastewater has a near-neutral pH and is anaerobic, it is suitable for SRB survival. Furthermore, the low concentration of heavy metals eliminates their toxicity to the SRB bacteria. The SRB growing on the membrane in the SRB membrane reaction zone can remove SO42- in the wastewater. 2- It is reduced to H2S, and H2S can react with residual heavy metals (such as Cu) in wastewater. 2+ Pb 2+ (etc.) reaction, forming a metal sulfide precipitate, with Cu 2+ For example, the reaction formula is: Cu 2+ +H₂S→CuS↓+2H + The sediment, under gravity, falls to the bottom of the SRB membrane reactor to form a sludge layer. After further treatment by the SRB membrane reactor, the acidic mine wastewater meets discharge standards and can be discharged through the third outlet. It is understood that the physicochemical processor 2 includes a first housing 2a, a second inlet 21 and a second outlet 26 disposed on the side wall of the first housing, and the first sedimentation layer 22, the Fe filter layer 23, and the second sedimentation layer 24 disposed within the first housing. The SRB membrane reactor 3 includes a second housing 3a, a third inlet 31 and a third outlet 34 disposed on the side wall of the second housing, and the SRB membrane reaction zone 32 disposed within the second housing.

[0055] The technical solution of this invention can effectively remove heavy metals from acidic mine wastewater, and SO42- Effective removal is also possible. Microbial treatment of acidic mine wastewater eliminates the need for external chemical reagents and results in low operating costs. It should be noted that the SRB membrane reaction zone includes a fiber membrane and SRB grown on the fiber membrane. The fiber membrane can be a sheet membrane or a hollow fiber membrane, preferably a hollow fiber membrane with microfiltration pores. The hollow fiber membrane is made of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polypropylene (PP), or polyurethane (PU), preferably PVDF. The surface of the hollow fiber membrane is hydrophobically treated, exhibiting a water contact angle of 151.9–156.2° and a roll-off angle of 9.6–22.6°, making it easier for SRB to adhere and grow on the membrane.

[0056] To ensure thorough mixing of the acidic mine wastewater and H2S in mixer 1, mixer 1 includes a first liquid inlet 11, a first air inlet 12, and a mixing chamber connected to the first liquid inlet and the first air inlet; a first drain outlet 13 is connected to the mixing chamber; and / or,

[0057] The SRB membrane reactor 3 also includes a second exhaust port 36 disposed above the SRB membrane reaction zone 32, and the second exhaust port 36 is connected to the first air inlet 12 through a pipe.

[0058] By adopting the above technical solution, the acidic mine wastewater to be treated flows into the mixing chamber from the first inlet, and H2S gas flows into the mixing chamber through the first air inlet and mixes with the acidic mine wastewater to form acidic mine wastewater containing H2S. The acidic mine wastewater containing H2S is discharged through the first outlet 13. It should be noted that the mixer 1 in the above technical solution is a pipeline mixer, which can be a static baffle type pipeline mixer, an orifice plate type pipeline mixer, or a three-way pipeline mixer, preferably a static baffle type pipeline mixer; the shell structure of the static baffle type pipeline mixer is made of fiberglass, PP, or stainless steel, preferably PP. It can be understood that in the embodiments of the present invention, a water pump 14 is also included. The outlet of the water pump is connected to the first inlet 11 through a pipeline. The water pump pumps the acidic mine wastewater to be treated into the mixer 1. The water pump can be a diaphragm pump, a rotor pump, or a magnetic pump, preferably a diaphragm pump.

[0059] Because SRBs that grow on the SRB membrane reaction zone can remove SO42- from wastewater... 2-The H2S is reduced to H2S. Since the acidic mine wastewater to be treated needs to be mixed with H2S in mixer 1, in one embodiment of the present invention, the H2S generated in the SRB membrane reaction zone can be used as the source of H2S required in mixer 1. The H2S generated in the SRB membrane reaction zone is discharged through the second exhaust port and flows to the first air inlet through the pipeline, which is beneficial to the recycling of H2S. The material of the pipeline used to transport H2S is PVC, fiberglass, or PP, preferably PP.

[0060] In order to better collect the H2S generated in the SRB membrane reaction zone, the SRB membrane reactor 3 also includes a gas collection chamber 35 located adjacent to the second exhaust port 36.

[0061] By adopting the above technical solution, a gas collection chamber is provided in the second housing above the SRB membrane reaction zone. The gas collection chamber is located between the SRB membrane reaction zone and the second exhaust port, so as to better collect the H2S generated in the SRB membrane reaction zone and make full use of the H2S. It should be noted that the gas collection chamber is open at both ends, with the bottom diameter larger than the top diameter. The second exhaust port is located above the gas collection chamber and is connected to it. It can be understood that the second exhaust port is located at the top of the second housing.

[0062] To effectively separate gas, liquid, and solid phases, the SRB membrane reactor 3 further includes a second three-phase separation zone 33 disposed between the SRB membrane reaction zone 32 and the gas collection chamber; and / or,

[0063] The physical and chemical processor 2 also includes a first three-phase separation zone 25 disposed between the second precipitate layer 24 and the second drain port 26.

[0064] By adopting the above technical solution, the second three-phase separation zone can further intercept the precipitates in the wastewater, allowing them to slide to the bottom of the SRB membrane reactor. The second three-phase separation zone also allows for better separation of H2S gas from the wastewater, facilitating H2S collection. Furthermore, the wastewater treated in the SRB membrane reactor zone, after separation in the second three-phase separation zone, forms a supernatant that meets discharge standards. The first three-phase separation zone has the same function as the second three-phase separation zone, both serving as gas-liquid-solid three-phase separation zones. The wastewater treated in the second sedimentation layer, after separation in the first three-phase separation zone, further intercepts the precipitates, allowing H2 to overflow effectively, and the resulting waste liquid is discharged to the SRB membrane reactor for further treatment. It should be noted that the three-phase separators in the first and second three-phase separation zones are made of PVC, fiberglass, or PP, preferably fiberglass. The first three-phase separation zone 25 is located within the first shell 2a, and the second three-phase separation zone 33 is located within the second shell 3a.

[0065] In order to recycle the generated H2, the internal circulation system for treating acidic wastewater using SRB also includes a membrane gas supply system, which includes a gas collection tank.

[0066] The physical and chemical processor 2 also includes a first exhaust port 27 disposed above the second precipitation layer 24;

[0067] The SRB membrane reactor 3 also includes a fourth air inlet 315 corresponding to the SRB membrane reaction zone 32;

[0068] The first exhaust port 27 is connected to the air inlet pipe of the gas collecting tank, and the fourth air inlet 315 is connected to the air outlet pipe of the gas collecting tank.

[0069] By adopting the above technical solution, H2 overflowing from the second sedimentation layer can be discharged through the first exhaust port and flow into the gas collection tank, and then into the SRB membrane reaction zone. H2 and organic pollutants in the wastewater can serve as electron donors required for SRB growth and metabolism, thereby effectively removing SO4 from the wastewater. 2- The gas is reduced to H2S. After being utilized by the SRB, the gas escaping from the SRB membrane reaction zone contains almost no H2.

[0070] The generated H2 can also be used as a gas to strip H2S and to flush the precipitates attached to the sediment layer. The internal circulation system for treating acidic wastewater using SRB also includes an aeration system, which includes a dissolved air tank 4.

[0071] The SRB membrane reactor 3 also includes a supernatant discharge pipe 312 corresponding to the third discharge port 34;

[0072] The gas inlet pipe 41 of the dissolved gas tank is connected to the first exhaust port 27, the liquid inlet 42 of the dissolved gas tank is connected to the supernatant discharge pipe 312, and the exhaust port of the dissolved gas tank 4 is provided with a first exhaust pipe 29 extending into the bottom of the physicochemical processor 2 and a second exhaust pipe 38 extending into the bottom of the SRB membrane reactor 3.

[0073] By adopting the above technical solution, the H2 overflowing from the second sedimentation layer 24 can be discharged through the first exhaust port and flow to the dissolved gas tank. The supernatant formed in the SRB membrane reactor can flow to the dissolved gas tank through the supernatant discharge pipe and mix with H2 to form dissolved gas water. When the dissolved gas water is released, a large number of micro-nano-level H2 bubbles are generated and enter the physical and chemical processor 2 through the first exhaust pipe. They also enter the SRB membrane reactor through the second exhaust pipe. The H2 bubbles entering the physical and chemical processor can wash away the precipitates attached to the first sedimentation layer 22 and the second sedimentation layer 24, so that the precipitates can slide more fully to the bottom of the physical and chemical processor 2 and form a sludge layer. The H2 bubbles entering the SRB membrane reactor can effectively blow off the H2S generated in the SRB membrane reaction zone, so that the H2S can overflow more fully. It also helps to improve the toxicity of wastewater to SRB.

[0074] It should be noted that a pressure pump 314 is installed on the supernatant discharge pipe 312. The pressure pump not only facilitates pumping the supernatant into the dissolved gas tank, but also creates pressure to ensure that the supernatant and hydrogen are mixed more thoroughly, thus guaranteeing the aeration effect of the formed dissolved gas water. The pressure pump can be a self-priming pump, a centrifugal pump, or a rotary pump, preferably a self-priming pump. It is understood that, in order to better control the aeration effect, a first valve 45 is also installed on the air inlet pipe 41 of the dissolved gas tank, a second valve 313 is installed on the supernatant discharge pipe 312, and a dissolved gas discharge main pipe 43 is installed at the exhaust port of the dissolved gas tank 4. The outlet end of the dissolved gas discharge main pipe is connected to the first exhaust pipe and the second exhaust pipe, respectively, and a third valve 44 is installed on the dissolved gas discharge main pipe. Initially, the first valve is open, while the second and third valves are closed, allowing hydrogen to enter the dissolved gas tank. When the pressure inside the dissolved gas tank reaches 1.0 MPa, the first valve closes, and when the supernatant level in the SRB membrane reactor reaches a preset height, the second valve opens, and the pressurization pump starts, pumping the supernatant into the dissolved gas tank. When the pressure inside the dissolved gas tank reaches 4.5 MPa, the second valve and the pressurization pump close, and the third valve opens, supplying H2 bubbles to the physicochemical processor 2 and the SRB membrane reactor through the first and second exhaust pipes.

[0075] In order to provide H2 to the SRB membrane reaction zone more stably, the gas collection tank includes a first gas collection tank 51 and a second gas collection tank 52. The first gas collection tank 51 is provided with a first inlet pipe 511 at the inlet and a first outlet pipe 512 at the outlet.

[0076] The second gas collecting tank 52 is provided with a second air inlet pipe 521 at the air inlet and a second air outlet pipe 522 at the air outlet.

[0077] Valves are installed on the first air inlet pipe, the first air outlet pipe, the second air inlet pipe, and the second air outlet pipe.

[0078] The technical solution of this invention ensures a relatively stable reaction in the SRB membrane reaction zone by using two parallel gas collecting tanks, the first and second, to alternately supply H2. Specifically, an H2 discharge manifold 213 is provided on the first exhaust port 27. The outlet end of the H2 discharge manifold is connected to the inlet pipe of the dissolved gas tank, as well as to the first and second inlet pipes. Thus, the hydrogen discharged from the physical and chemical processor 2 can flow into the dissolved gas tank through the inlet pipe of the dissolved gas tank, into the first gas collecting tank through the first inlet pipe, and into the second gas collecting tank through the second inlet pipe. A fourth valve 513 is provided on the first inlet pipe 511, a fifth valve 514 is provided on the first outlet pipe 512, a sixth valve 523 is provided on the second inlet pipe 521, and a seventh valve 524 is provided on the second outlet pipe 522. Both the first outlet pipe 512 and the second outlet pipe 522 are connected to the fourth inlet port 315 via pipes. Initially, valves 5 and 7 are closed, while valves 4 and 6 are open, allowing H2 to enter the first and second gas collecting tanks. When the pressure in both tanks reaches 1.0 MPa, valves 4 and 6 close, and valve 5 opens, allowing the first gas collecting tank to begin supplying gas to the SRB membrane reaction zone. When the pressure in the first gas collecting tank drops to 0.1 MPa, valve 5 closes, valve 4 opens, and hydrogen continues to be added to the first gas collecting tank, while valve 7 remains open, allowing the second gas collecting tank to supply gas to the SRB membrane reaction zone. When the pressure in the second gas collecting tank drops to 0.1 MPa, valve 7 closes, valve 6 opens, and hydrogen continues to be added to the second gas collecting tank, while valve 4 closes, valve 5 opens, and the first gas collecting tank continues to supply gas to the SRB membrane reaction zone. This process begins the next gas supply cycle. The first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, and the seventh valve are electric ball valves, pneumatic ball valves, electric butterfly valves, pneumatic butterfly valves, electric gate valves, or pneumatic gate valves, preferably pneumatic ball valves.

[0079] The first gas collecting tank, the second gas collecting tank, and the dissolved gas tank of the present invention are made of carbon steel corrosion-resistant material, 304 stainless steel material, or 316 stainless steel material, preferably 304 stainless steel material.

[0080] In order to better aerate the physical and chemical processor 2 and the SRB membrane reactor 3, the aeration system further includes a first aeration pipe 28 disposed below the second liquid inlet 21, and the air inlet end of the first aeration pipe 28 is connected to the first exhaust pipe 29.

[0081] The SRB membrane reactor 3 also includes a second aeration pipe 37 disposed below the third liquid inlet 31, the air inlet end of the second aeration pipe 37 being connected to the second exhaust pipe 38.

[0082] By adopting the above technical solution, the H2 bubbles amplified in the first aeration pipe can flush away the sediments attached to the first sedimentation layer 22 and the second sedimentation layer 24, allowing the sediments to slide more fully to the bottom of the physicochemical processor 2 and form a sludge layer; the H2 bubbles amplified in the second aeration pipe can effectively blow off the H2S generated in the SRB membrane reaction zone, allowing the H2S to overflow more fully, which not only facilitates the recycling of H2S but also helps to reduce the toxicity of wastewater to SRB. It should be noted that the first and second aeration pipes are made of PVC, ABS, or PP, preferably PP. It is understood that the first aeration pipe 28 is located inside the first shell, and the second aeration pipe 37 is located inside the second shell.

[0083] To achieve more thorough physicochemical treatment of the wastewater, the first sedimentation layer 22 includes a plurality of parallel first inclined tubes 221. The length of each first inclined tube is 1–1.5 m, the horizontal inclination angle of each first inclined tube is 30–60°, and the inner diameter of each first inclined tube is 35–80 mm; and / or,

[0084] The Fe filter layer 23 includes a lower support mesh, an upper support mesh, and iron-containing particles 231 disposed between the lower support mesh and the upper support mesh; and / or

[0085] The second sedimentation layer 24 includes a plurality of parallel second inclined tubes 241, the length of the second inclined tube is 1 to 1.5 m, the horizontal inclination angle of the second inclined tube is 30 to 60°, and the inner diameter of the second inclined tube is 35 to 80 mm.

[0086] The technical solution of this invention optimizes the structure of the first sedimentation layer, allowing sulfides in the wastewater to precipitate and slide effectively to the bottom of the physicochemical processor 2, forming a sludge layer. Preferably, the first inclined tube is 1.2m long, has a horizontal inclination angle of 60°, and an inner diameter of 50mm. It should be noted that the first inclined tube is made of fiberglass, PVC, or PP, preferably PP.

[0087] The technical solution of this invention optimizes the structure of the Fe filter layer 23, enabling the wastewater to come into more sufficient contact with iron-containing particles, thus ensuring a more complete reaction. It should be noted that the iron-containing particles are iron shavings, iron particles, or iron filings, preferably iron particles; the diameter of the iron-containing particles is 3–20 mm, preferably 5–10 mm; and the height of the Fe filter layer 23 is 1–2 m, preferably 1 m.

[0088] The technical solution of this invention optimizes the structure of the second sedimentation layer, allowing the sediment in the wastewater to slide to the bottom of the physicochemical processor 2 and form a sludge layer. Preferably, the second inclined tube is 1.2m long, has a horizontal inclination angle of 30°, and an inner diameter of 35mm. It should be noted that the second inclined tube is made of fiberglass, PVC, or PP, preferably PP.

[0089] The sludge layer at the bottom of the physical and chemical processor 2 and the SRB membrane reactor 3 contains iron ore concentrate, which can be recycled. The internal circulation system for treating acidic wastewater using SRB also includes a sludge concentrate recovery system, which includes a sludge pump 6.

[0090] The physical and chemical processor 2 also includes a first mud hopper 210 disposed below the second liquid inlet 21, and a first mud discharge pipe 211 disposed at the bottom of the first mud hopper 210;

[0091] The SRB membrane reactor 3 also includes a second sludge hopper 39 disposed below the third inlet 31, and a second sludge discharge pipe 310 disposed at the bottom of the second sludge hopper 39.

[0092] Both the first sludge discharge pipe 211 and the second sludge discharge pipe 310 are connected to the inlet of the sludge pump 6.

[0093] In the technical solution of this invention, a first sludge hopper for collecting sludge is provided at the bottom of the physicochemical processor 2, and a second sludge hopper for collecting sludge is provided at the bottom of the SRB membrane reactor 3. An eighth valve 212 is provided on the first sludge discharge pipe 211, and a ninth valve 311 is provided on the second sludge discharge pipe 310. The eighth and ninth valves are normally closed. When it is necessary to discharge sludge to recover refined iron ore, the eighth and ninth valves are opened, and the sludge pump is started to discharge the sludge containing refined iron ore from the first and second sludge hoppers. It should be noted that the sludge pump is a diaphragm pump, a rotary pump, or a screw pump, preferably a screw pump; the eighth and ninth valves are electric ball valves, pneumatic ball valves, electric butterfly valves, pneumatic butterfly valves, electric gate valves, or pneumatic gate valves, preferably pneumatic butterfly valves. It can be understood that the first sludge hopper is located at the bottom of the first housing, and the second sludge hopper is located at the bottom of the second housing.

[0094] The present invention also proposes an acidic wastewater treatment method, which adopts the above-mentioned internal circulation system for treating acidic wastewater using SRB. The specific structure of the internal circulation system for treating acidic wastewater using SRB is as described in the above embodiments. Since this acidic wastewater treatment method adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0095] Performance test

[0096] The concentration of heavy metal ions and SO4 in the acidic wastewater from the mine to be treated 2- The concentrations are shown in Table 1 below.

[0097] The example group uses the above-described acidic wastewater treatment method of the present invention to treat the acidic mine wastewater to be treated. The mixer is a static baffle-type pipe mixer. The length of the first inclined tube in the first sedimentation layer is 1.2m, the horizontal inclination angle of the first inclined tube is 60°, and the inner diameter of the first inclined tube is 50mm. The diameter of the iron particles in the Fe filter layer is 5-10mm, the iron content in the iron particles is 91.8% by mass, and the height of the Fe filter layer is 1m. The length of the second inclined tube in the second sedimentation layer is 1.2m, the horizontal inclination angle of the second inclined tube is 30°, and the inner diameter of the second inclined tube is 35mm. The first inclined tube and the second... The inclined tubes are all made of PP; the three-phase separator in the first three-phase separation zone is made of fiberglass; the fiber membrane in the SRB membrane reaction zone is a PVDF hollow fiber membrane, exhibiting a water contact angle of 152.2° and a roll-off angle of 10.6°, with a volume ratio of SRB to fiber membrane of 1:10; the three-phase separator in the second three-phase separation zone is made of fiberglass; during wastewater treatment, aeration is carried out through the first and second aeration pipes, air supply from the gas collection tank, and H2S recycling; the hydraulic retention time of the wastewater in the physicochemical processor is 1.5 h, and the hydraulic retention time in the SRB reactor is 12 h. After the acidic wastewater to be treated is treated using the above method, the supernatant discharged from the third drain outlet is collected, and the concentration of heavy metal ions and SO4 in the supernatant (effluent) is detected. 2- The concentration.

[0098] Comparative Example 1: Based on the above example group, the difference is that it does not contain the Fe filter layer, and the rest is the same as the above example group.

[0099] Comparative Example 2: Based on the above example group, the difference is that it does not contain the SRB membrane reaction zone, and the rest is the same as the above example group.

[0100] After treating acidic mine wastewater, the above-described examples and comparative examples showed that the levels of metal ions and SO4 in the effluent were significantly reduced. 2-The concentration of [specific concentration] was measured, and the results are shown in Table 1 below.

[0101] Table 1. Metal ions and SO4 in the effluent of the Example Group and Comparative Group. 2- concentration

[0102]

[0103] As can be seen from the test results in Table 1, the embodiment group of the present invention can effectively remove Fe from wastewater. 2+ Cu 2+ Pb 2+ and SO4 2- The wastewater meets discharge standards after treatment, indicating that the technical solution of this invention combines the first precipitation layer, Fe filter layer, second precipitation layer, and SRB membrane reaction zone, which can effectively remove heavy metal ions and SO4 from the wastewater. 2- Comparative Example 1, lacking an Fe filter layer, and Comparative Example 2, lacking an SRB membrane reaction zone, both failed to effectively remove heavy metal ions and SO4 from the wastewater. 2- This indicates that the Fe filter layer and the SRB membrane reaction zone are key influencing factors in the treatment of acidic mine wastewater.

[0104] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An internal circulation system for treating acidic wastewater using SRB, characterized in that, include: A mixer for mixing acidic wastewater to be treated with H2S, the mixer having a first drain outlet for discharging the acidic wastewater containing H2S. The physical and chemical processor includes, from bottom to top, a second inlet connected to the first outlet, a first sedimentation layer, an Fe filter layer, a second sedimentation layer, and a second outlet, which are sequentially arranged and connected to the first outlet. The SRB membrane reactor includes, from bottom to top, a third inlet connected to the second drain outlet, an SRB membrane reaction zone, and a third drain outlet, arranged sequentially. The acidic wastewater to be treated contains Fe. 2+ Cu 2+ Pb 2+ and SO4 2- ; The mixer has a first liquid inlet, a first air inlet, and a mixing chamber connected to the first liquid inlet and the first air inlet, and the first liquid outlet is connected to the mixing chamber; the SRB membrane reactor further includes a second exhaust port disposed above the SRB membrane reaction zone, and the second exhaust port is connected to the first air inlet. It also includes a membrane gas supply system, which includes a gas collection tank; the physicochemical processor also includes a first exhaust port disposed above the second precipitation layer; the SRB membrane reactor also includes a fourth air inlet disposed corresponding to the SRB membrane reaction zone; the first exhaust port is connected to the air inlet pipe of the gas collection tank, and the fourth air inlet is connected to the air outlet pipe of the gas collection tank.

2. The internal circulation system for treating acidic wastewater using SRB as described in claim 1, characterized in that, The SRB membrane reactor also includes a gas collection chamber located adjacent to the second exhaust port.

3. The internal circulation system for treating acidic wastewater using SRB as described in claim 2, characterized in that, The SRB membrane reactor further includes a second three-phase separation zone disposed between the SRB membrane reaction zone and the gas collection chamber; and / or, The physical and chemical processor also includes a first three-phase separation zone disposed between the second precipitate layer and the second drain outlet.

4. The internal circulation system for treating acidic wastewater using SRB as described in claim 1, characterized in that, The internal circulation system for treating acidic wastewater using SRB also includes an aeration system, which includes a dissolved air tank. The SRB membrane reactor also includes a supernatant discharge pipe corresponding to the third discharge port; The gas inlet pipe of the dissolved gas tank is connected to the first exhaust port, the liquid inlet of the dissolved gas tank is connected to the supernatant discharge pipe, and the exhaust port of the dissolved gas tank is provided with a first exhaust pipe extending into the bottom of the physicochemical processor and a second exhaust pipe extending into the bottom of the SRB membrane reactor.

5. The internal circulation system for treating acidic wastewater using SRB as described in claim 1, characterized in that, The gas collecting tank includes a first gas collecting tank and a second gas collecting tank. The first gas collecting tank is provided with a first inlet pipe at its inlet and a first outlet pipe at its outlet. The second gas collecting tank is provided with a second air inlet pipe at the air inlet and a second air outlet pipe at the air outlet. Valves are installed on the first air inlet pipe, the first air outlet pipe, the second air inlet pipe, and the second air outlet pipe.

6. The internal circulation system for treating acidic wastewater using SRB as described in claim 4, characterized in that, The aeration system also includes a first aeration pipe disposed below the second liquid inlet, wherein the air inlet end of the first aeration pipe is connected to the first exhaust pipe. The SRB membrane reactor also includes a second aeration pipe disposed below the third inlet, the inlet end of the second aeration pipe being connected to the second exhaust pipe.

7. The internal circulation system for treating acidic wastewater using SRB as described in claim 1, characterized in that, The first sedimentation layer comprises a plurality of parallel inclined tubes, the length of which is 1–1.5 m, the horizontal inclination angle of which is 30–60°, and the inner diameter of which is 35–80 mm; and / or, The Fe filter layer includes a lower support mesh, an upper support mesh, and iron-containing particles disposed between the lower support mesh and the upper support mesh; and / or The second precipitation layer includes a plurality of parallel second inclined tubes, the length of which is 1 to 1.5 m, the horizontal inclination angle of which is 30 to 60°, and the inner diameter of which is 35 to 80 mm.

8. The internal circulation system for treating acidic wastewater using SRB as described in claim 1, characterized in that, The internal circulation system for treating acidic wastewater using SRB also includes a sludge concentrate recovery system, which includes a sludge pump. The physical and chemical processor also includes a first mud hopper disposed below the second liquid inlet, and a first mud discharge pipe is provided at the bottom of the first mud hopper; The SRB membrane reactor also includes a second sludge hopper located below the third inlet, and a second sludge discharge pipe is provided at the bottom of the second sludge hopper. Both the first sludge discharge pipe and the second sludge discharge pipe are connected to the inlet of the sludge pump.

9. A method for treating acidic wastewater using an internal circulation system for treating acidic wastewater according to any one of claims 1 to 8.

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