An open oxygen channel

Abstract

The utility model belongs to acid mine wastewater treatment technical field, concretely relates to an open type oxygen channel. The drop water area is equipped with baffle; The water distribution area is equipped with limestone gradation filler with 20-40cm of particle size; The reaction area is filled with filter material; The water collecting area is equipped with cobble with 20-40cm of particle size; The sedimentation area carries out water guiding efficiency through the guide vane of inlet end, and the pollutants in the reaction area form the precipitate after physical and chemical action and are discharged here, and the sludge collecting hopper is arranged in the sludge collecting area of the lower part of sedimentation area, and the sludge is discharged regularly. The open type oxygen channel can alleviate the blockage of limestone and improve the treatment efficiency of limestone.

Description

Technical Field

[0001] This utility model relates to the field of acidic mine wastewater treatment technology, specifically to an open oxygen channel. Background Technology

[0002] The description of the background technology in this utility model pertains to related technologies and is used merely for illustration and to facilitate understanding of the utility model content. It should not be construed as the applicant explicitly believing or presuming that the applicant believes it to be prior art on the filing date of the first application.

[0003] Acid mine drainage (AMD) is mainly generated from the oxidation of sulfur-containing ores in closed coal mines. It is characterized by low pH, high iron ion concentration, and the presence of various heavy metals and sulfide minerals. It causes environmental pollution to downstream soil and water resource protection areas, and creates a series of ecological and environmental problems around the mining area, making it one of the most environmentally hazardous types of mine wastewater. The mainstream treatment processes for acid mine drainage are mainly divided into active and passive treatment methods. Active treatment technology primarily uses chemical neutralization, adding dissolved Ca(OH)₂ or NaOH. This method has a fast reaction rate and high treatment efficiency, but suffers from problems such as large dosage, high reagent costs, and excessive sediment. Therefore, many researchers currently use passive treatment technology, primarily employing carbonate rocks (CaCO₃ content higher than 90%) as the preferred filter media for neutralizing AMD. During the treatment process, Ca... 2+ With SO4 2- CaSO4 crystals are easily formed, causing a large amount of CaSO4 scale to form on pipes and pools. This "shell" formed on the rock surface blocks the continuous acid-base reaction, resulting in low limestone dissolution efficiency, poor sustainability, frequent replacement of limestone packing, high labor intensity, and low treatment efficiency of acidic mine wastewater. Utility Model Content

[0004] The purpose of this invention is to provide a novel open oxygen channel for treating acidic mine water from abandoned coal mines with low pH and high iron content. This reduces limestone clogging, improves limestone treatment efficiency, reduces manual labor intensity, and increases limestone solubility using a sustainable operation approach. This achieves effective treatment of acidic water from closed coal mines, resulting in significant economic, environmental, and social benefits.

[0005] An open oxygen channel, characterized in that it comprises, from top to bottom: a cascade zone, a water distribution zone, a reaction zone, a water collection zone, a sedimentation zone, and an outlet channel;

[0006] The cascading zone is equipped with baffles; the water distribution zone is equipped with limestone graded filler with a particle size of 20-40cm; the reaction zone is filled with filter media; the water collection zone is equipped with pebbles with a particle size of 20-40cm; the sedimentation zone guides water through a guide plate at the inlet end, and pollutants in the reaction zone form precipitates through physical and chemical reactions and are discharged here. A sludge collection hopper is installed in the sludge collection zone at the bottom of the sedimentation zone for periodic sludge discharge.

[0007] Furthermore, a baffle plate is provided in the drop zone, which is located in the middle of the drop zone. The baffle plate is 0.5-0.8m lower than the water inlet end of the drop zone, and the water outlet end of the drop zone is 0.5-0.8m lower than the baffle plate. The height of the baffle plate is 0.5m.

[0008] Furthermore, the filling height of the packing material in the water distribution area is 0.8-1.5m, and the bulk density is 1.3-1.8t / m³. 3 The effective content of calcium carbonate in the filter media of the reaction zone is >90%; the pebble filling height in the water collection zone is 0.8-1.5m, and the bulk density is 1.6-1.8t / m³. 3 .

[0009] Furthermore, the filter media in the reaction zone includes calcite, limestone, marble, or dolomite, wherein the effective calcium carbonate content is >90%; the filling height is 0.8-1.5m, and the bulk density is 1.3-1.8t / m³. 3 The bottom is designed with a slope of 3%-30%.

[0010] Furthermore, the packing layer in the reaction zone can be a homogeneous filter media or a composite filter media. The composite filter media, from bottom to top, consists of gravel, limestone φ200-250, limestone φ50-100, and limestone φ20-50. The composition of the packing in the reaction zone is shown in the table below.

[0011]

[0012] Furthermore, perforated aeration pipes are installed at the bottom of the reaction zone, employing intermittent aeration with an aeration rate of 0.5-3.0 L gas / m³. 3 Water·min, each aeration cycle lasts 2 hours of aeration followed by 0.5 hours of cessation; after a total of 4 consecutive aeration cycles, aeration is stopped; intermittent aeration lasts for a total of 10 hours, followed by 14 hours of cessation.

[0013] Furthermore, a mud collection hopper is provided in the mud collection area, and a mud discharge pipe is provided at the bottom of the mud collection hopper, with an electric valve installed on the mud discharge pipe.

[0014] The present invention has the following beneficial effects:

[0015] This invention addresses the problems of limestone clogging, low utilization efficiency, poor sustainability, and frequent replacement of limestone packing materials. It improves the treatment efficiency of acidic mine wastewater, reduces treatment costs, facilitates operation and maintenance, and enables continuous operation.

[0016] Open oxygen channels (OLDs) technology can be used for long-term treatment and can also be combined with other passive systems to maximize treatment and metal removal efficiency. This technology has a wide range of applications and is flexible in its use.

[0017] Through the above methods, this utility model can improve the service life of limestone with simple processes, inexpensive reagents, and a sustainable operating concept, and achieve effective treatment of acidic water in closed coal mines, resulting in significant economic, environmental, and social benefits. Attached Figure Description

[0018] Figure 1 A cross-sectional view of the open oxygen channel of this utility model;

[0019] Figure 2 This is a horizontal layout diagram of the open oxygen channel of this utility model;

[0020] Figure 3 This is a diagram showing the layout of the open oxygen channel pipeline of this utility model;

[0021] Figure 4 This is a schematic diagram of the structure of the open oxygen channel of this utility model;

[0022] Figure 5 This is a schematic diagram of the pipeline layout structure of the open oxygen channel of this utility model. Detailed Implementation

[0023] The present application will now be described in some embodiments of this utility model with reference to specific examples.

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, in the following description, different "an embodiment" or "an embodiment" do not necessarily refer to the same embodiment. Different embodiments can be substituted or combined, and for those skilled in the art, other implementation methods can be obtained based on these embodiments without creative effort.

[0025] Combined with appendix Figure 1-5 An open oxygen channel 100, from top to bottom, includes: a drop zone 1, a water distribution zone 2, a reaction zone 3, a water collection zone 4, a sedimentation zone 5, and an outlet channel 6;

[0026] The drop zone 1 is equipped with baffles (such as...) Figure 3As shown, the water flows into the drop well through the overflow weir 7 in the drop zone 1; the water distribution zone 2 is equipped with limestone graded filler with a particle size of 20-40cm, a filling height of 0.8-1.5m, and a bulk density of 1.3-1.8t / m³. 3 The reaction zone 3 is filled with filter media containing >90% effective calcium carbonate content; the water collection zone 4 contains pebbles with a particle size of 20-40cm, a filling height of 0.8-1.5m, and a bulk density of 1.6-1.8t / m³. 3 The sedimentation zone 5 is guided by a guide plate at the inlet end (forming a water guiding zone 8). Pollutants in the reaction zone 3 are discharged here after physical and chemical reactions to form precipitates. The upper part of the sedimentation zone 5 is the clear water zone 9, and the lower sludge collection zone 10 is equipped with a sludge collection hopper (with a sludge discharge pipe 11 at the bottom) for regular sludge discharge.

[0027] In some embodiments of this utility model, the filter media in the reaction zone 3 includes calcite, limestone, marble, or dolomite; the filter media filling height is 0.8-1.5m; and the slope is 3%-30%.

[0028] In some embodiments of this utility model, the packing layer of the reaction zone 3 is a relatively graded packing layer, and the particle size distribution of the packing is shown in the table below:

[0029]

[0030] In some embodiments of this utility model, a perforated aeration pipe 13 (with an aeration main pipe 12 connected to it in the vertical direction at the starting end) is provided at the bottom of the reaction zone 3. Intermittent aeration is adopted. Under the experimental conditions, the aeration volume is 0.5-3.0 L gas / m3 water·min, the aeration time is 2 hours of aeration, 0.5 hours of cessation, and so on, for a total of 4 consecutive aeration cycles before stopping aeration. The intermittent aeration lasts for 10 hours, followed by a 14-hour cessation of aeration. The equipment required for aeration is a blower. The power supply for the blower can be a solar power system. Solar energy is a clean and pollution-free energy source with the characteristics of good environmental protection, long sustainability, high flexibility, and low energy cost.

[0031] In some embodiments of this utility model, a mud collecting hopper is provided in the mud collecting area 10, and a mud discharge pipe 11 is provided at the bottom of the mud collecting hopper, with an electric valve provided on the mud discharge pipe 11.

[0032] An open oxygen channel 100 is applied in the field of mine wastewater treatment. Wastewater flows by gravity from the collection pipe to the drop well, and after being further oxygenated by the overflow weir, it enters the water distribution zone 2. After being evenly distributed, it enters the reaction zone 3 through the perforated flower wall. Here, pollutants are transformed into fine mud-water mixtures by the physicochemical action of the graded filter media. The mud-water mixture is quickly flushed to the collection zone 4 by the specific slope setting in the reaction tank and then enters the rear guide zone. After being guided by the baffle plate, the sediment settles into the sludge collection hopper under gravity, and the supernatant is discharged into the effluent channel 6. The sediment is collected in the sludge collection hopper and discharged into the sludge pipe for centralized treatment. Perforated aeration pipes are installed in the reaction zone 3 to remove pollutants through intermittent aeration.

[0033] Open limestone drains (OLDs) treatment technology involves filling ditches with limestone without sealing. Acidic, substandard water flows into the limestone-containing ditches, reacts with the limestone, and raises the pH of the water flow. During prolonged operation, a large amount of sediment accumulates on the limestone surface, resulting in metal precipitation. The main components of the precipitation are oxides, hydroxides, and solid phases of hydroxysulfates. This surface sediment affects the release of alkalinity from the limestone. When treating acidic, substandard water containing Fe and Al, the Fe produced during the neutralization process... 3+ And Al 3+ The hydroxide precipitates clog the pores of limestone, and this system is often used as a unit in an overall passive treatment system. OLDs can be used for long-term treatment. OLCs combined with other passive systems can maximize treatment and metal removal efficiency.

[0034] Limestone filter media is filled into the newly constructed open oxygen channel 100 or the river channel. To prevent limestone blocks from sliding downstream, a water-retaining sill 200 is added to a section of the river channel. The stream water is guided through the filler material inside the gabion, allowing the acidic water to be neutralized by the limestone, increasing the pH of the incoming water. Some iron and aluminum ions are neutralized by alkaline ions, forming precipitated compounds, which are periodically discharged through a sludge discharge pipe installed in the sludge collection area at the end of the structure. The open oxygen channel 100 is designed to regulate the inflow rate through the adjustment of inlet valves or gates. A drain pipe with a drain valve is installed at the outlet. By adjusting the opening of the valves, the system operates at the highest liquid level, which is level with the height of the filter media, when the inflow is large. The submerged liquid level varies with the inflow rate. When the water volume is small, the filter media operates at a low liquid level, which can still achieve the removal effect. During the high-water season, the liquid level operates at a high liquid level.

[0035] The open oxygen channel 100 system is divided into the following parts: 1. Drop zone; 2. Water distribution zone; 3. Reaction zone; 4. Water collection zone; 5. Sedimentation zone; 6. Outlet channel.

[0036] (1) In drop zone 1, AMD wastewater is dropped through a 0.5m high baffle plate, which can entrain some air, increase the dissolved oxygen (DO) concentration in the water, and facilitate Fe production. 2+ Converted to Fe 3+ ion.

[0037] (2) In the water distribution zone 2, AMD wastewater passes through a 20-40cm limestone graded packing material, so that the acidic wastewater entering the reaction zone 3 can flow evenly through the packing layer, so that each part of the filter material layer can participate in the neutralization reaction to the maximum extent, and so that the open oxygen channel 100 can exert its best treatment capacity.

[0038] (3) In reaction zone 3, in order to effectively alleviate the blockage problem of open oxygen channel 100, improvements can be made in terms of packing particle size and gradation ratio, slope, reaction time, packing flushing, and packing aeration.

[0039] In reaction zone 3, limestone-graded packing is used to maximize the participation of each component in the neutralization reaction, ensuring the open oxygen channel 100 achieves its optimal processing capacity and minimizing packing blockage. For the packing material selection, large-particle-size reaction packing is chosen to increase porosity and reduce blockage between packing elements.

[0040] Based on the natural advantages of the mine, without any power measures, high-speed water flow washes the sediment to sedimentation zone 5, restoring the activity of limestone and enabling continuous reaction.

[0041] Perforated aeration pipes are installed at the bottom of reaction zone 3, and intermittent aeration is adopted to improve the dissolved oxygen utilization rate and iron ion removal rate in reaction zone 3. At the same time, the filter media is backwashed regularly to increase the mutual friction between the filter media and effectively solve and prevent the clogging problem caused by calcium sulfate crystallization and metal ion precipitation.

[0042] Filter media selection: calcite, limestone, marble, dolomite, etc.;

[0043] Filter media effective component content: calcium carbonate effective content >90%; bulk density: 1.3-1.8 t / m³ 3 ;

[0044] Filter media filling height: 1-1.5m;

[0045] When the filter media filling height is too high, it is not convenient for the iron sludge to be discharged into the tail sludge discharge area in a timely manner. If the iron sludge cannot be discharged in time, it is easy for iron sludge to form caking in the filling area, which is not conducive to the further progress of the reaction. When the filter media filling height is too low, it will result in a large area occupied by the acidic water treatment tank, insufficient space utilization, and high infrastructure investment.

[0046] Design slope: 3%-30% (Optimal design slope: 20%, taking into account construction costs and the feasibility of the structure, the given range of design slope values)

[0047] If the design slope is too small, a thick layer of calcium sulfate and precipitates will quickly form on the surface of the filter media, hindering the interaction between the filter media and the AMD and reducing the reaction rate. If the design slope is too large, the packing material will be difficult to install, and its submersion depth will be insufficient, resulting in insufficient contact time between the filter media and the AMD, which is not conducive to the reaction.

[0048] After cascading aeration, the AMD flows through a relatively graded limestone packing layer. Well-graded limestone is used to minimize clogging; the packing particle size distribution is detailed in Table 1. Larger limestone particles are selected to increase porosity between packing materials and reduce clogging.

[0049] Table 1. Filter Media Composition, Particle Size, and Thickness

[0050]

[0051] By selecting and formulating suitable packing materials, and utilizing the complementary effects between them, the decontamination effect of the open oxygen channel 100 can be effectively improved while avoiding filter media clogging and extending the operating cycle. Furthermore, the research results on the treatment effect of AMD on acidic water from the surface, middle, and bottom layers are consistent. Since packing clogging mainly occurs in the surface packing, timely replacement of the surface packing can also improve the clogging problem to some extent.

[0052] The open oxygen channel 100, after simple modifications based on the river's course, can achieve a designed slope of 3%-30%, allowing for a high flow velocity. During neutralization, iron and aluminum react with limestone to form loose flocculent sediment and a film layer. This sediment remains suspended at high flow velocities, facilitating the scouring of the underlying iron oxide coating and ensuring the fresh limestone surface remains exposed. The limestone reaction can proceed continuously. Perforated aeration pipes are installed at the bottom of reaction zone 3, employing intermittent aeration to improve dissolved oxygen utilization and periodically backwash the filter media, oxidizing and degrading organic matter, and effectively solving and preventing clogging problems caused by calcium sulfate crystallization and metal ion precipitation.

[0053] Under the same experimental conditions, with the same filter media added to acidic AMD water, only the aeration condition was changed. At a retention time of 5 hours, the iron ion concentration in the effluent of the aerated and non-aerated media changed significantly. When limestone was intermittently aerated, the iron ion concentration in the effluent was 182.55 mg / L, with a removal rate of 30%. At this time, the iron ion concentration in the non-aerated limestone media remained at 239.25 mg / L, with a removal rate of only 10%. At a retention time of 24 hours, the change in iron ion concentration in the effluent of the aerated and non-aerated media was even more pronounced. When limestone was intermittently aerated, the iron ion concentration in the effluent was 70.04 mg / L, with a removal rate reaching 73%. At this time, the iron ion concentration in the non-aerated limestone media was 146.87 mg / L, with a removal rate of only 43.5%. Specific data are shown in Table 2.

[0054] Table 2. Iron ion concentration in effluent (mg / L) using limestone packing material under non-aeration and intermittent aeration conditions.

[0055]

[0056] (4) In the water collection area 4, considering that CaSO4 crystals and metal ion precipitates will cause blockage of the triangular weir, 20-40cm pebbles are used as the water collection area 4 to collect and store the AMD-treated water.

[0057] (5) In the sedimentation zone 5, the AMD wastewater is guided by the guide plate at the inlet end. The sediment formed in the reaction zone 3 is discharged here. A sludge collection hopper is set in the sedimentation zone 5 to discharge sludge regularly. An electric valve can be set on the sludge discharge pipe to discharge the settled sludge by opening the electric valve at regular intervals.

[0058] In sedimentation zone 5, the high-speed wastewater is guided and slowed down by the guide plate at the inlet end to prevent the bottom sediment from being washed away. Ferrous hydroxide and other precipitates settle and are discharged here. The precipitates are removed in time to prevent them from accumulating on the surface of the packing material and forming a scale film, thereby increasing the porosity of the packing material, restoring the activity of the limestone, and improving the service life of the limestone.

[0059] (6) The blower and electric valve are powered by solar panels, which not only solves the energy supply problem, but also reduces management costs. It is especially suitable for closed mining areas located in remote areas or areas with underdeveloped power grids.

[0060] Case study of the construction of open oxygen channels in a certain location:

[0061] The design flow rate for this project is 0.5 m³ / h.

[0062] Design influent water quality: Design influent pH value: 2.50-3.15; Total iron ions: 157-300 mg / L; Total manganese ions: 35.7-58.5 mg / L;

[0063] The equipment consists of an inlet pipe, a drop pool, an open oxygen channel, and filter media; the components are connected by stainless steel flexible hoses.

[0064] Structural dimensions: 10×0.5×0.5m, made of 316 stainless steel;

[0065] Filter media: limestone, filling height 300mm, particle size 20-50mm;

[0066] Aeration system: Water is introduced into the cascade pool for natural oxygenation;

[0067] Designed stay duration: 5 hours;

[0068] Design slope: 10%;

[0069] Open the bottom mud discharge valve every 3 days to discharge mud.

[0070] After three months of operation, the effects of treatment with open oxygen channels are as follows:

[0071] The removal rate is shown below:

[0072] The removal efficiency of the treatment equipment: effluent pH value: 4.0-4.5, total iron ions: 113.2-201.5 mg / L, total manganese ions: 30.4-46.8 mg / L, then the removal rate of total iron is approximately 27.8%-32.8%, and the removal rate of total manganese ions is approximately 14.8%-20.0%.

[0073] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of this utility model and is not intended to limit this utility model. For those skilled in the art, this utility model can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An open oxygen channel, characterized in that, From top to bottom, it includes: a drop zone, a water distribution zone, a reaction zone, a water collection zone, a sedimentation zone, and an outlet channel; The cascading zone is equipped with baffles; the water distribution zone is equipped with limestone graded filler with a particle size of 20-40cm; the reaction zone is filled with filter media; the water collection zone is equipped with pebbles with a particle size of 20-40cm; the sedimentation zone guides water through a guide plate at the inlet end, and pollutants in the reaction zone form precipitates through physical and chemical processes and are discharged here. A sludge collection hopper is installed in the sludge collection zone at the bottom of the sedimentation zone for periodic sludge discharge.

2. The open oxygen channel according to claim 1, characterized in that, The cascading water feature is equipped with a baffle plate located in the middle of the cascading water feature. The baffle plate is 0.5-0.8m lower than the inlet end of the cascading water feature and 0.5-0.8m lower than the outlet end of the cascading water feature. The height of the baffle plate is 0.5m.

3. The open oxygen channel according to claim 1, characterized in that, The filling height of the packing material in the water distribution area is 0.8-1.5m, and the bulk density is 1.3-1.8t / m³. 3 The effective content of calcium carbonate in the filter media of the reaction zone is >90%; the pebble filling height in the water collection zone is 0.8-1.5m, and the bulk density is 1.6-1.8t / m³. 3 .

4. The open oxygen channel according to claim 1, characterized in that, The filter media in the reaction zone includes calcite, limestone, marble, or dolomite, with an effective calcium carbonate content >90%; the filling height is 0.8-1.5m, and the bulk density is 1.3-1.8t / m³. 3 The bottom is designed with a slope of 3%-30%.

5. The open oxygen channel according to claim 1, characterized in that, The packing layer in the reaction zone can be made of homogeneous filter media or composite filter media. The composite filter media, from bottom to top, consists of gravel, limestone (φ200-250), limestone (φ50-100), and limestone (φ20-50). The composition of the packing in the reaction zone is shown in the table below.

6. The open oxygen channel according to claim 1, characterized in that, Perforated aeration pipes are installed at the bottom of the reaction zone, using intermittent aeration with an aeration rate of 0.5-3.0 L gas / m³. 3 Water·min, each aeration cycle lasts 2 hours of aeration followed by 0.5 hours of cessation; after a total of 4 consecutive aeration cycles, aeration is stopped; intermittent aeration lasts for a total of 10 hours, followed by 14 hours of cessation.

7. The open oxygen channel according to claim 1, characterized in that, The mud collection area is equipped with a mud collection hopper, and the bottom of the mud collection hopper is equipped with a mud discharge pipe, which is equipped with an electric valve.

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