Mine water deep purification treatment system

Abstract

The application discloses a kind of mine water depth purification treatment systems, including sequentially communicating raw water homogenization regulating unit, modified coagulation precipitation unit, silicon carbide ceramic membrane precision filtration unit, nanofiltration grading desalination unit and sterile conditioning steady pressure water supply unit.The application is through silicon carbide inorganic ceramic membrane process flow, combined with modified coagulation enhanced removal of heavy metals, nanofiltration salt reduction reduces energy consumption and improves system recovery, realizes mine water efficient upgrading, can meet the dual needs of mine area living area direct drinking water supply and surrounding town water supply plant raw water supply, reduces system investment and operation cost, improves mine water resource utilization rate and regional water supply guarantee capacity.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, and in particular relates to a deep purification system for mine water. Background Technology

[0002] my country is rich in coal resources, but the mining process generates large amounts of mine water. This mine water is characterized by large volume, high concentration of suspended solids, high salt content, and high hardness. Its composition is complex, containing suspended solids such as coal dust and rock powder, as well as soluble salts such as calcium, magnesium, sodium, sulfate, and chloride ions. For a long time, large quantities of mine water have been discharged directly without effective treatment, resulting in a serious waste of water resources and pollution of the surrounding ecological environment.

[0003] With increasingly stringent national standards for water resource protection and mine water discharge, the resource utilization of mine water has become an urgent need for the sustainable development of coal mining enterprises. Especially in arid and semi-arid mining areas such as Shanxi, Shaanxi, and Inner Mongolia, where water resources are extremely scarce, purifying mine water for drinking or domestic use is of great significance in alleviating regional water shortages.

[0004] Existing mine water treatment processes mostly employ conventional methods such as coagulation sedimentation and filtration, resulting in effluent quality that fails to meet drinking water standards. Some solutions utilizing membrane treatment technology also suffer from problems such as unstable pretreatment effects, severe membrane fouling, low system recovery rates, and high energy consumption. Therefore, there is an urgent need to develop a mine water deep purification system with a rational process, stable operation, and high effluent quality. Summary of the Invention

[0005] The purpose of this invention is to provide a deep purification system for mine water. By simplifying the process flow through silicon carbide inorganic ceramic membranes, combined with modified coagulation to enhance the removal of heavy metals and nanofiltration to reduce energy consumption and improve system recovery rate, the system achieves efficient quality improvement of mine water. It can meet the dual needs of direct drinking water supply in mining areas and raw water replenishment for water supply plants in surrounding towns, reduce system investment and operation and maintenance costs, and improve the resource utilization rate of mine water and the regional water supply security.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: This invention is a deep purification system for mine water, comprising a raw water homogenization and conditioning unit, a modified coagulation and sedimentation unit, a silicon carbide ceramic membrane precision filtration unit, a nanofiltration staged desalination unit, and a sterile conditioning and pressure stabilizing water supply unit connected in sequence. The raw water homogenization adjustment unit is used to collect raw mine water, complete the homogenization and balance of water quality and quantity and pre-sedimentation of large particulate impurities, buffer the fluctuation of mine water quality and quantity, and adapt to large-scale continuous water supply load. The modified coagulation and sedimentation unit, by adding modified composite coagulants and coagulant aids, combined with a three-stage gradient flocculation and inclined tube sedimentation process, specifically removes water colloids, fine suspended solids, heavy metal ions and macromolecular organic pollutants, and stably controls the effluent turbidity to below 2 NTU. The silicon carbide ceramic membrane precision filtration unit adopts an external pressure cross-flow precision filtration mode. Relying on the rigid porous structure of the sintered silicon carbide inorganic membrane, it efficiently intercepts residual fine particles, flocculated residues, bacterial debris, macromolecular organic matter and fine colloidal impurities, and outputs stable clear water with low turbidity and low pollution index. The nanofiltration staged desalination unit is based on the dual principles of physical sieving and charge repulsion. It selectively removes excess calcium and magnesium ions, sulfates, heavy metal residues and excess inorganic salts from water, achieving precise staged desalination, reducing operating pressure and increasing energy consumption, while improving water recycling rate. The sterile conditioning and pressure stabilizing water supply unit uses ultraviolet light to inhibit bacteria in the purified water. It adopts a dual-path pressure stabilizing water supply structure, with one path supplying drinking water to the mining area's living quarters at constant pressure, and the other path delivering water to surrounding town water plants as raw water replenishment, thus realizing the large-scale and integrated resource utilization of mine water.

[0007] Furthermore, the modified coagulation and sedimentation unit is equipped with a fully automatic precision dosing device and a three-stage gradient stirring mechanism. It uses a self-made modified polyferric-aluminum composite coagulant, which is prepared by compounding and modifying polyaluminum chloride, ferric sulfate and nano-bentonite. The dosage of modified polyferric-aluminum is 15-30 mg / L, and the dosage of anionic polyacrylamide coagulant is 0.8-2.0 mg / L. The three-stage gradient stirring parameters are: first-stage rapid stirring 220-280 r / min, duration 1-1.5 min; second-stage medium-speed stirring 120-180 r / min, duration 2-3 min; and third-stage slow stirring 40-80 r / min, duration 8-12 min. The overall flocculation and sedimentation time is controlled at 30-45 min.

[0008] Furthermore, the silicon carbide ceramic membrane precision filtration unit adopts a porous sintered silicon carbide inorganic membrane module with a membrane pore size of 0.05–0.1 μm, which can withstand a wide range of water quality from pH 2 to 12. The operating pressure is controlled at 0.1–0.35 MPa, and a high-flow cross-flow filtration mode is adopted. The system integrates three regeneration mechanisms: high-pressure clean water backwashing, air-water combined flushing, and online chemical cleaning. Clean water backwashing is automatically performed every 15–30 minutes, and air-water combined deep flushing is carried out daily at regular intervals. The system has a continuous water recovery rate of ≥94% and can withstand the shock load of high turbidity and high organic matter water quality.

[0009] Furthermore, the nanofiltration staged desalination unit is sequentially equipped with a 5μm precision security filter, a low-pressure high-pressure pump, and a low-pressure selective polyamide nanofiltration membrane element. The nanofiltration system operates at a pressure of 0.5-1.2MPa and has an operating water temperature range of 12-38℃. The nanofiltration membrane has a removal rate of ≥95% for divalent harmful ions, a single nanofiltration system recovery rate of ≥85%, and a comprehensive water resource recovery rate of ≥88% for the entire purification system. The nanofiltration concentrate adopts a differentiated reuse mode, with high-salt concentrate being transported to the mine dust removal and underground grouting equipment for reuse, and low-salt concentrate being returned to the raw water homogenization and conditioning unit for recycling.

[0010] Furthermore, the raw water homogenization and conditioning unit is a closed anti-corrosion conditioning tank. The tank is equipped with an intermittent aeration and stirring device, a liquid level sensor, an online pH meter, and an online turbidity meter to monitor the influent water quality and quantity parameters in real time, so as to realize the adaptive homogenization and conditioning of the influent. The closed structure throughout the process prevents secondary pollution of the water body.

[0011] Furthermore, the aseptic conditioning and pressure stabilizing water supply unit includes an ultraviolet sterilization device, a pressure stabilizing constant flow water supply unit, and dual independent water supply interfaces. The two interfaces are respectively connected to the water supply network of the mining area's residential area and the water inlet pipeline of the surrounding town's water supply plant. The finished water end is equipped with a multi-parameter online water quality monitoring instrument to monitor key indicators such as turbidity, pH, conductivity, microorganisms, and heavy metals in real time.

[0012] Furthermore, the entire system is equipped with a PLC intelligent frequency conversion control system, which enables the electrical linkage of each unit to achieve adaptive operation. It can automatically adjust the dosage of chemicals, membrane operating pressure, membrane cleaning cycle and water supply flow according to the fluctuation of mine water influent quality and changes in water supply load. The system has automatic fault alarm, real-time storage of operating data and remote operation and maintenance control functions. The overall modular structure allows for flexible addition or reduction of equipment groups according to the scale of water supply in mining areas and towns, enabling rapid expansion and adaptation.

[0013] The present invention has the following beneficial effects: 1. The process is simple and reliable, the core components have excellent durability, and the operation and maintenance costs are low. The silicon carbide ceramic membrane has the characteristics of high strength, acid and alkali resistance, oxidation resistance, resistance to organic pollution, and can be cleaned with high-intensity water washing agents. It has low flux decline and a stable service life that is 3-5 times that of traditional organic ultrafiltration membranes. It does not require frequent shutdowns for chemical cleaning, which greatly reduces the operation and maintenance costs and downtime losses of large-scale water supply projects.

[0014] 2. Stable effluent quality, suitable for large-scale water supply in dual scenarios. After multiple treatments including silicon carbide membrane precision filtration, nanofiltration desalination, and photocatalytic terminal purification, the effluent has extremely low turbidity, controllable pollutant residue, and high biological safety. The uniformity and stability of the water quality not only meet the GB 5749-2022 standard for drinking water, but also fully meet the raw water requirements of surrounding town water supply plants, achieving water reuse and maximizing resource utilization.

[0015] 3. Energy-saving and high resource utilization rate. The overall water recovery rate of the entire system is ≥88%, and the concentrated water is reused separately according to quality, with no wastewater discharge or waste; nanofiltration is used instead of reverse osmosis, which significantly reduces the system's power consumption while ensuring the quality of the produced water. The energy-saving advantages are significant for long-term operation on a large scale, and the environmental and economic benefits are outstanding.

[0016] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; The attached diagram lists the components represented by each number as follows: 1. Raw water homogenization and conditioning unit; 2. Modified coagulation and sedimentation unit; 3. Silicon carbide ceramic membrane precision filtration unit; 4. Nanofiltration staged desalination unit; 5. Aseptic conditioning and pressure stabilizing water supply unit. Detailed Implementation

[0018] The technical solution of the present invention will be further described in detail below with reference to specific preferred embodiments.

[0019] Example 1: Purification treatment of ordinary complex mine water (high organic content, conventional mineralization) This embodiment targets conventional mine water in coal mines, with the following influent water quality: turbidity 80-120 NTU, COD ≤ 80 mg / L, total dissolved solids 600-900 mg / L, containing trace amounts of iron, manganese, and humic substances. The innovative process of this invention is used for drinking water treatment, and the specific steps are as follows: S1. Raw water homogenization and pre-sedimentation: The raw mine water is sent into the raw water homogenization and conditioning unit 1, with a hydraulic retention time of 10 hours. Intermittent aeration and stirring are used to naturally settle coarse impurities and balance the water quality and quantity.

[0020] S2, Modified Coagulation Enhanced Pretreatment: Water treated by S1 enters the modified coagulation sedimentation unit 2, and 22 mg / L modified polyferric-aluminum composite coagulant and 1.2 mg / L anionic polyacrylamide are added. After three-stage gradient stirring reaction, sedimentation is carried out for 40 min. The turbidity of the effluent is reduced to below 1.5 NTU, and the removal rate of heavy metals and macromolecular organic matter is ≥90%.

[0021] S3, Precision purification with silicon carbide ceramic membrane: The pretreated effluent is sent to the silicon carbide ceramic precision filter unit 3. The silicon carbide ceramic membrane has a pore size of 0.08μm and is set to an operating pressure of 0.22MPa. It adopts a continuous cross-flow filtration mode, with automatic water backwashing every 25 minutes and daily timed air-water combined deep flushing. It effectively intercepts residual micro-colloids, fine flocs, and trace amounts of residual organic matter, producing uniform and stable water with an SDI ≤ 0.4, which fully meets the high-precision water inlet requirements of the nanofiltration unit.

[0022] S4, Nanofiltration Staged Desalination: The S3 permeate enters the nanofiltration staged desalination unit 4. After passing through a 5μm precision filter, it is pressurized to 0.6MPa and enters the nanofiltration system. It selectively removes heavy metals and scale-causing ions such as calcium, magnesium, and sulfate. The nanofiltration recovery rate is 86%, and the overall comprehensive recovery rate is 92%.

[0023] S5. Aseptic conditioning and storage: The product water after S4 treatment enters the aseptic conditioning and pressure stabilizing water supply unit 5, and is stored in a sealed manner after ultraviolet sterilization treatment.

[0024] Tests showed that the effluent from this embodiment had a turbidity of ≤0.1 NTU, COD of ≤10 mg / L, no heavy metals detected, and zero microbial indicators, fully meeting and exceeding the GB 5749-2022 standard for drinking water. It had a sweet taste, and the equipment operated continuously for 6 months without significant membrane fouling, demonstrating stable operation.

[0025] Example 2: Purification Treatment of High-Mineralization and High-Pollution Mine Water This embodiment of the system is adapted for the treatment of highly polluted and highly fluctuating mine water in metal mines. The influent water quality parameters are: total dissolved solids 1800-2200 mg / L, COD≤110 mg / L, turbidity 150-200 NTU, and the water quality fluctuates greatly. The overall system architecture is the same as in Embodiment 1, and the operating parameters are optimized as follows: the dosage of modified coagulant is adjusted to 28 mg / L, and the dosage of coagulant aid is 1.8 mg / L; the operating pressure of silicon carbide ceramic membrane is increased to 0.3 MPa, the backwash interval is shortened, and the frequency of deep rinsing is increased; the operating pressure of nanofiltration system is adjusted to 1.0 MPa to enhance the selective desalination effect under high salinity conditions.

[0026] This embodiment employs a differentiated concentrate reuse strategy: 35% of the low-salinity concentrate produced by nanofiltration is recycled to a homogenization and equalization tank for further purification, while 65% of the high-salinity concentrate is collected and used for underground grouting and dust suppression in the mining area, achieving zero wastewater waste. Testing has shown that this system can stably treat highly polluted mine water over a long period, consistently meeting effluent quality standards, exhibiting excellent shock resistance, and showing no membrane clogging or water quality fluctuations. It can reliably provide large-scale raw water replenishment to surrounding town water plants.

Claims

1. A deep purification and treatment system for mine water, characterized in that, It includes a raw water homogenization and conditioning unit (1), a modified coagulation and sedimentation unit (2), a silicon carbide ceramic membrane precision filtration unit (3), a nanofiltration staged desalination unit (4), and a sterile conditioning and pressure stabilizing water supply unit (5), which are connected in sequence.

2. The mine water deep purification system according to claim 1, characterized in that: The modified coagulation sedimentation unit (2) is equipped with a fully automatic precision dosing device and a three-stage gradient stirring mechanism. It uses a self-made modified polyferric-aluminum composite coagulant, which is prepared by compounding and modifying polyaluminum chloride, ferric sulfate and nano-bentonite. The dosage of modified polyferric-aluminum is 15-30 mg / L, and the dosage of anionic polyacrylamide coagulant is 0.8-2.0 mg / L. The three-stage gradient stirring parameters are: first-stage rapid stirring 220-280 r / min, duration 1-1.5 min; second-stage medium-speed stirring 120-180 r / min, duration 2-3 min; third-stage slow stirring 40-80 r / min, duration 8-12 min. The overall flocculation sedimentation time is controlled at 30-45 min.

3. The mine water deep purification system according to claim 1, characterized in that: The silicon carbide ceramic membrane precision filtration unit (3) adopts a porous sintered silicon carbide inorganic membrane module with a membrane pore size of 0.05–0.1μm. It can withstand a wide range of water quality with pH 2–12 and the operating pressure is controlled at 0.1–0.35MPa. It adopts a high-flow cross-flow filtration mode. The system integrates three regeneration mechanisms: high-pressure clean water backwash, air-water combined flushing, and online chemical cleaning. It automatically performs clean water backwash every 15–30 minutes and performs air-water combined deep flushing on a daily schedule. The system has a continuous water recovery rate of ≥94% and can withstand the impact load of high turbidity and high organic matter water quality.

4. The mine water deep purification system according to claim 1, characterized in that: The nanofiltration staged desalination unit (4) is configured with a 5μm precision security filter, a low-pressure high-pressure pump and a low-pressure selective polyamide nanofiltration membrane element in sequence. The nanofiltration system operates at a pressure of 0.5-1.2MPa and the operating water temperature range is 12-38℃. The nanofiltration membrane has a removal rate of ≥95% for divalent harmful ions, a single nanofiltration system recovery rate of ≥85%, and a comprehensive water resource recovery rate of ≥88% for the entire purification system. The nanofiltration concentrate adopts a graded reuse mode. The high-salt concentrate is transported to the dust removal and underground grouting equipment in the mining area for reuse, while the low-salt concentrate is returned to the raw water homogenization adjustment unit for circulation treatment.

5. The mine water deep purification system according to claim 1, characterized in that: The raw water homogenization adjustment unit (1) is a closed anti-corrosion adjustment tank. The tank is equipped with an intermittent aeration and stirring device, a liquid level sensor, a pH online detector and a turbidity online detector to monitor the water quality and quantity parameters of the influent in real time, realize the adaptive homogenization adjustment of the influent, and the closed structure throughout the process prevents secondary pollution of the water body.

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