Sequential reaction device suitable for passive treatment of acid mine wastewater
By designing a sequential reaction device and utilizing multi-stage treatment with manganese oxidizing bacteria and sulfate-reducing bacteria, the problems of low manganese ion removal efficiency and high cost in traditional systems were solved, achieving efficient and low-cost purification of acidic mine wastewater.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HANGZHOU DADI ENVIRONMENTAL PROTECTION ENG CO LTD
- Filing Date
- 2025-05-11
- Publication Date
- 2026-05-08
AI Technical Summary
In the existing technology, the traditional AMD passive treatment system, which mainly uses sulfate-reducing bacteria, cannot effectively capture Mn(II), resulting in poor treatment efficiency of acidic mine wastewater with high manganese ion concentration. In addition, it requires a continuous supply of organic matter, which increases costs. High heavy metal concentrations may cause the system to crash.
A sequential reaction device is designed, including a water storage tank, a neutralization reaction tank, a MOB reactor, and an SRB reactor. It uses manganese-oxidizing bacteria to oxidize Mn(II) to generate Mn(III/IV) oxides to adsorb heavy metals, and combines multi-stage treatment, utilizing terrain drop and microbial reactors to achieve multi-stage purification.
It improves manganese ion removal efficiency, reduces operating costs, is suitable for treating acidic mine wastewater with high manganese ion concentrations, achieves multi-stage purification effects, has strong adaptability and flexibility, and is suitable for unattended operation.
Smart Images
Figure CN224212536U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of water, wastewater, sewage or sludge treatment, and in particular to a sequential reaction device suitable for the passive treatment of acidic mine wastewater. Background Technology
[0002] Waste rock dumps and mined-out areas from sulfur-containing metal mining often expose minerals such as pyrite (FeS2) to the natural environment. Under the combined action of oxygen, water, and microorganisms, this generates acidic mine wastewater (AMD). AMD typically has a pH below 4.0 and contains high concentrations of sulfates and heavy metal ions, such as iron (Fe), manganese (Mn), zinc (Zn), lead (Pb), cadmium (Cd), copper (Cu), and arsenic (As). Without collection and treatment, AMD can lead to rapid acidification of water bodies and soil in its basin, and excessive concentrations of heavy metal ions. These heavy metals can also accumulate in organisms through the food chain, posing a serious threat to the safety of the watershed's aquatic and soil ecosystems and the health of residents. Traditional physical and chemical treatment processes require expensive equipment for operation and maintenance. For mining areas requiring long-term remediation but lacking operational support, especially abandoned mining areas, developing passive AMD treatment technologies based on microbial processes is an inevitable trend.
[0003] The advantages of AMD passive treatment technology, which uses microbial methods as its basic process, are as follows: First, microbial methods remove pollutants from wastewater by utilizing the metabolic activities of specific microorganisms, reducing the risk of secondary pollution and making it more environmentally friendly than traditional chemical methods. Second, since microorganisms can self-reproduce and exert their effects under appropriate conditions, microbial treatment units are usually operated passively, resulting in lower operating costs, fewer maintenance requirements, and even unattended operation under certain conditions. In addition, microbial treatment technology has a synergistic effect, exhibiting greater flexibility and adaptability when treating wastewater with complex compositions.
[0004] In passive treatment technologies for acidic mine wastewater, common techniques include using sulfate-reducing bacteria (SRB) to reduce sulfate to hydrogen sulfide, and then utilizing S... 2-The combined action of these two types of microorganisms can effectively treat various pollutants in acidic mine wastewater, providing a more sustainable solution for the development of passive treatment technologies for acidic mine wastewater. These microorganisms form metal sulfides with extremely low solubility to remove heavy metals, and manganese-oxidizing bacteria (MOBs) oxidize Mn(II) to Mn(IV), forming insoluble manganese oxides, thereby removing manganese ions from wastewater.
[0005] However, existing technologies still have the following drawbacks:
[0006] (1) Due to the special chemical properties of manganese, the traditional passive treatment system of AMD, which is mainly based on sulfate-reducing bacteria (SRB), cannot effectively capture Mn(II), resulting in poor treatment efficiency of Mn(II) in AMD with high manganese ion concentration, thus causing manganese to harm the water environment and aquatic ecology of the basin.
[0007] (2) Metabolic reactions using SRB require a continuous supply of electron donors, which increases the demand for organic matter and results in high costs, making implementation challenging;
[0008] (3) When the concentration of heavy metals in AMD is too high, the activity of SRB will be inhibited, which may reduce the processing efficiency of the processing system, and in severe cases may even cause the system to crash. Utility Model Content
[0009] This invention solves the problems existing in the prior art and provides a sequential reaction device suitable for the passive treatment of acidic mine wastewater.
[0010] The technical solution adopted in this utility model is a sequential reaction device suitable for passive treatment of acidic mine wastewater. The device includes a water storage tank, a neutralization reaction tank, a MOB reactor, and an SRB reactor connected in sequence by pipelines. The outlet heights of the water storage tank, the neutralization reaction tank, the MOB reactor, and the SRB reactor decrease sequentially. It should be noted that the MOB reactor and the SRB reactor are presented as tanks.
[0011] The lower part of the neutralization reaction tank, MOB reactor and SRB reactor are respectively provided with corresponding liquid inlets, and the neutralization reaction tank, MOB reactor and SRB reactor are provided with corresponding reaction units.
[0012] Preferably, the distance between the outlet of the water storage tank and the inlet of the neutralization reaction tank is greater than a preset value, and an overflow port is provided above the outlet of the neutralization reaction tank.
[0013] Preferably, any of the pipes is equipped with a flow regulating valve.
[0014] Preferably, a water distribution pipe is provided on the inner bottom of the neutralization reaction tank, MOB reactor and SRB reactor. The inlet of the water distribution pipe is connected to the liquid inlet of the corresponding neutralization reaction tank, MOB reactor and SRB reactor, and the water distribution pipe is provided with a liquid outlet.
[0015] Preferably, the reaction unit inside the neutralization reaction tank includes several alkaline gravel layers for neutralizing acidic mine wastewater.
[0016] Preferably, the particle size of the alkaline gravel layer gradually decreases from bottom to top.
[0017] Preferably, the reaction units within both the MOB reactor and the SRB reactor include a carrier for inoculating a predetermined proportion of microbial cells.
[0018] Preferably, the reaction unit includes a plurality of bio-suspension spheres, and the carrier is filled inside the bio-suspension spheres.
[0019] Preferably, the bio-suspension spheres used in conjunction with the carrier are also filled with a carbon source donor.
[0020] Preferably, the SRB reactor is equipped with a sealing cover, and the sealing cover has an exhaust gas collection hole.
[0021] This utility model relates to a sequential reaction device suitable for the passive treatment of acidic mine wastewater. The device includes a water storage tank, a neutralization reaction tank, a MOB reactor, and an SRB reactor, which are connected sequentially by pipelines with progressively decreasing outlet heights. Corresponding inlets are provided at the lower parts of the neutralization reaction tank, MOB reactor, and SRB reactor, and corresponding reaction units are provided inside the neutralization reaction tank, MOB reactor, and SRB reactor.
[0022] The beneficial effects of this invention are as follows: by setting up a sequential reaction vessel, based on water quality characteristics, and by making reasonable use of terrain and oxygen supply conditions, the collected AMD is subjected to a three-stage treatment process of neutralization, microbial manganese removal, and microbial sulfate and heavy metal removal, thus completing passive treatment; by introducing manganese-oxidizing bacteria, the Mn(III / IV) manganese oxides generated by them promote the oxidation process of Mn(II) and further adsorb the remaining heavy metal ions, thereby significantly improving the manganese removal efficiency of the system. Combined with the multi-stage treatment of the neutralization reaction tank and SRB reactor, the pH of the effluent is increased while removing heavy metal ions and sulfate from AMD, thus completing the multi-stage purification of AMD; it is particularly suitable for acidic heavy metal mine wastewater with high manganese ion concentration. Attached Figure Description
[0023] Figure 1This is a schematic diagram of the structure of this utility model;
[0024] Figure 2 This is a top view structural diagram of the water distribution pipe in this utility model;
[0025] Figure 3 This is a cross-sectional view of the neutralization reaction vessel in this utility model.
[0026] Figure 4 This is a cross-sectional view of the MOB reactor or SRB reactor in this utility model. Detailed Implementation
[0027] The present invention will be further described in detail below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto.
[0028] This utility model relates to a sequential reaction device suitable for passive treatment of acidic mine wastewater. The device includes a water storage tank 1, a neutralization reaction tank 2, a MOB reactor 3 and an SRB reactor 4 connected in sequence by pipelines. The height of the outlet 5 of the water storage tank 1, the neutralization reaction tank 2, the MOB reactor 3 and the SRB reactor 4 decreases sequentially.
[0029] The lower parts of the neutralization reaction tank 2, MOB reactor 3 and SRB reactor 4 are respectively provided with corresponding liquid inlets 6, and the neutralization reaction tank 2, MOB reactor 3 and SRB reactor 4 are provided with corresponding reaction units.
[0030] In this invention, by setting up a water storage tank 1, a neutralization reaction tank 2, a MOB reactor 3, and an SRB reactor 4 connected in sequence, four-stage treatment operations are completed: water volume adjustment, neutralization treatment, manganese removal, sulfate removal, and heavy metal removal. For a specific embodiment:
[0031] Water storage tank 1 has a volume of 2000 L and can be used to regulate the water output. During the wet season, it can store some AMD to ensure water supply during the dry season.
[0032] Neutralization reaction vessel 2 is a 500 L vessel used to carry out a neutralization reaction to neutralize the highly acidic AMD;
[0033] MOB reactor 3 is a 500 L tank inoculated with manganese-oxidizing bacteria to ensure the system can handle the high Mn content in AMD. 2+ The effect of going there;
[0034] SRB reactor 4 is a 500 L tank inoculated with sulfate-reducing bacteria, used to remove sulfate and heavy metal ions from AMD and increase the pH of the effluent.
[0035] In this invention, to prevent backflow, the outlets 5 of the neutralization reaction tank 2, MOB reactor 3, and SRB reactor 4 are successively lowered from the ground. For example, in the implementation process, they are set to 1.0 meters, 0.8 meters, and 0.6 meters respectively. Generally speaking, the distance between the previous outlet 5 and the next outlet 5 can be between 0.1 and 0.6 meters, or can be set by those skilled in the art according to actual needs.
[0036] In this invention, manganese-oxidizing bacteria are introduced that can increase the rate of Mn(II) oxidation by several orders of magnitude through enzyme catalysis. The Mn(III) / Mn(IV) oxides generated by these bacteria can further adsorb free Mn(II), thereby greatly improving the manganese removal efficiency of the system. Combined with the multi-stage treatment of neutralization reaction tank 2 and SRB reactor 4, the pH of the effluent is increased while removing heavy metal ions and sulfate from AMD, thus completing the multi-stage purification of AMD.
[0037] The distance between the outlet 5 of the water storage tank 1 and the inlet 6 of the neutralization reaction tank 2 is greater than a preset value, and an overflow port 7 is provided above the outlet 5 of the neutralization reaction tank 2.
[0038] Each of the aforementioned pipelines is equipped with a flow regulating valve 8.
[0039] In the implementation of this utility model, the elevation difference of the site can be fully utilized, such as a 7.2-meter elevation difference, as the driving force of the water flow. There is no need to configure an additional power source. In practical applications, the elevation difference can be adjusted according to the needs. Considering the existence of water flow impact, an overflow port is set above the liquid outlet 5 of the neutralization reaction tank 2, such as 10 cm away, to mitigate the impact of large water flow.
[0040] In this invention, the tanks are obviously connected by pipe fittings, such as corrosion-resistant PVC rigid pipes, and multiple flow regulating valves 8 are provided. At least the pipes between the reactors are equipped with flow regulating valves 8 to facilitate control of the hydraulic residence time of each part.
[0041] To ensure that the liquid entering each tank can fully react with the packing material in the tank, a water distribution pipe 9 is provided on the inner bottom of the neutralization reaction tank 2, MOB reactor 3 and SRB reactor 4. The inlet of the water distribution pipe 9 is connected to the liquid inlet 6 of the corresponding neutralization reaction tank 2, MOB reactor 3 and SRB reactor 4. The water distribution pipe 9 is provided with a liquid outlet 10. To be precise, the water distribution pipe 9 is a rigid corrosion-resistant PVC pipe.
[0042] In this invention, a reaction unit is configured on the water distribution pipe 9 of each tank. The reaction unit generally exists in the form of packing material. The following description is for each tank.
[0043] The reaction unit inside the neutralization reaction tank 2 includes several alkaline gravel layers 11 for neutralizing acidic mine wastewater.
[0044] The particle size of the alkaline gravel layer 11 gradually decreases from bottom to top.
[0045] In the specific implementation process, the tank is filled from bottom to top with alkaline gravel with a particle size ranging from 900 mm to 5 mm. Considering that the wear rate of alkaline gravel of different particle sizes is different, four layers of alkaline gravel with different particle sizes are set, from bottom to top: 300 ± 30 mm alkaline gravel, with a volume of about 100 L; 100 ± 10 mm alkaline gravel, with a volume of about 250 L; 20 ± 2 mm alkaline gravel, with a volume of about 30 L; and 5 ± 0.5 mm alkaline gravel, with a volume of about 20 L. In practical applications, the gravel is generally directly filled into the tank, so the volume of gravel added is directly recorded using the scale on the tank itself.
[0046] The reaction units in both the MOB reactor 3 and the SRB reactor 4 include carriers for inoculating microbial cells at a predetermined ratio. Specifically, this involves inoculating 5% (v / v) of manganese-oxidizing bacteria and sulfate-reducing bacteria that have been domesticated in the laboratory.
[0047] Furthermore, the reaction unit includes a plurality of bio-suspension balls 12, and the carrier is filled inside the bio-suspension balls 12.
[0048] The bio-suspension sphere 12, which is used in conjunction with the carrier, is also filled with a carbon source donor.
[0049] Specifically, different carbon sources are selected for different stages. During the reactor start-up phase, to shorten the waiting time, ferric ammonium citrate and sodium lactate, the dominant carbon sources, are added to MOB and SRB reactor 4 at a recommended concentration of 5 g / L to assist the rapid static growth of MOB and SRB bacteria and obtain sufficient MOB and SRB bacterial solutions. After 28 days of adaptation, 2000 mg / L of sulfate (the sulfate concentration in the influent is about 7000 mg / L) and 10 mg / L of manganese ions can be removed from AMD every 24 hours, and the pH of the effluent is stable at about 7.3. When the Mn(II) content and sulfate concentration in MOB and SRB reactor 4 are observed to decrease rapidly, it indicates that the reactor start-up is complete and continuous operation of the reactor can be carried out. Under the premise of ensuring the quality of the effluent, the flow regulating valves of MOB reactor 3 and SRB reactor 4 are gradually opened to reduce the hydraulic retention time from 7 days to 3 days, and inexpensive sodium carboxymethyl cellulose is gradually added to MOB reactor 3 and SRB reactor 4 as an intermediate substitute for a long-lasting carbon source.
[0050] After the effluent quality returns to its original level, biological suspension balls 12 (film-coated small balls) are added to both MOB reactor 3 and SRB reactor 4. An equal volume of porous sponge and sawdust is placed inside the balls to serve as carriers for MOB and SRB, and as a long-term carbon source donor, respectively, to ensure the long-term unattended operation of the device (the small balls only need to be replaced every six months). Generally, it is also necessary to install wire between the biological suspension balls 12 and the water distribution pipe to fix them relatively in place.
[0051] The bio-suspension balls 12 here are generally biofilm-attached microspheres, i.e., hollow spherical outer frames filled with several porous sponges and several sawdust particles. In the specific implementation process, 150 bio-suspension balls 12 (biofilm-attached microspheres) with a diameter of 10 cm are placed in each container. Almost equal volumes of 1 cm*1 cm porous sponges and sawdust particles with a particle size of about 200 mesh are placed in a perforated woven bag and then placed inside the spherical outer frame. Both can provide attachment for bacterial growth. The former can also effectively retain bacterial cells and reduce the loss of system biomass, while the small-diameter sawdust is not only inexpensive but also provides a long-lasting carbon source for bacterial growth. During the setup process, the bio-suspension balls 12 are strung together with wire or fishing line and placed inside the tank.
[0052] Since SRB can only grow in anaerobic or hypoxic environments, the present invention includes a sealing cover (not shown in the figure) in conjunction with the SRB reactor 4. The sealing cover has a tail gas collection hole (not shown in the figure) to collect H2S in the gas phase and prevent the release of toxic and harmful substances.
[0053] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.
[0054] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.
Claims
1. A sequential reaction device suitable for the passive treatment of acidic mine wastewater, characterized in that: The device includes a water storage tank, a neutralization reaction tank, a MOB reactor, and an SRB reactor connected in sequence by pipes, with the outlet heights of the water storage tank, neutralization reaction tank, MOB reactor, and SRB reactor decreasing sequentially. The lower part of the neutralization reaction tank, MOB reactor and SRB reactor are respectively provided with corresponding liquid inlets, and the neutralization reaction tank, MOB reactor and SRB reactor are provided with corresponding reaction units.
2. The sequential reaction device for passive treatment of acidic mine wastewater according to claim 1, characterized in that: The distance between the outlet of the water storage tank and the inlet of the neutralization reaction tank is greater than a preset value, and an overflow port is provided above the outlet of the neutralization reaction tank.
3. A sequential reaction device for passive treatment of acidic mine wastewater according to claim 1, characterized in that: Each of the aforementioned pipelines is equipped with a flow regulating valve.
4. A sequential reaction device for passive treatment of acidic mine wastewater according to claim 1, characterized in that: Water distribution pipes are provided on the inner bottom of the neutralization reaction tank, MOB reactor and SRB reactor. The inlet of the water distribution pipe is connected to the liquid inlet of the corresponding neutralization reaction tank, MOB reactor and SRB reactor. The water distribution pipe is provided with a liquid outlet.
5. A sequential reaction device for passive treatment of acidic mine wastewater according to claim 1, characterized in that: The reaction unit inside the neutralization reaction tank includes several alkaline gravel layers for neutralizing acidic mine wastewater.
6. A sequential reaction device for passive treatment of acidic mine wastewater according to claim 5, characterized in that: The particle size of the alkaline gravel layer gradually decreases from bottom to top.
7. A sequential reaction device for passive treatment of acidic mine wastewater according to claim 1, characterized in that: Both the MOB reactor and the SRB reactor contain reaction units that include carriers for inoculating microbial cells at a predetermined ratio.
8. A sequential reaction device for passive treatment of acidic mine wastewater according to claim 7, characterized in that: The reaction unit includes several bio-suspension spheres, and the carrier is filled inside the bio-suspension spheres.
9. A sequential reaction device for passive treatment of acidic mine wastewater according to claim 8, characterized in that: The bio-suspension spheres, which are used in conjunction with the carrier, are also filled with carbon source donors.
10. A sequential reaction device for passive treatment of acidic mine wastewater according to claim 1, characterized in that: The SRB reactor is equipped with a sealing cover, which has an exhaust gas collection hole.