Integrated coal-fired power plant heavy metal-containing wastewater treatment system

Abstract

The utility model relates to an integrated coal-fired power plant heavy metal-containing sewage treatment system and belongs to the technical field of water pollution control. The system is connected with a grit chamber, a microfiltration membrane filter, an ozone catalytic oxidation unit, a photocatalytic oxidation unit, an electrochemical oxidation unit, an ion exchange unit, a magnetic nano adsorption unit and an anaerobic biological filter in sequence through a water inlet through a grid. The anaerobic biological filter is connected with a membrane biological reactor and a reverse osmosis system through an aerobic biological reactor. The utility model system adopts compact design, has small land occupation, low operation cost, stable and efficient treatment effect, and the effluent quality reaches the national discharge standard or reuse requirement. The utility model not only significantly improves the removal efficiency of heavy metal ions, but also realizes energy recovery through sludge anaerobic digestion and biogas power generation, having remarkable environmental benefits and economic value.

Description

Technical Field

[0001] This utility model belongs to the field of industrial wastewater treatment technology, specifically relating to a wastewater treatment system and method for coal-fired power plants containing heavy metals that integrates intelligent control and multi-stage treatment technology. It is applicable to the treatment of industrial wastewater containing heavy metals such as mercury, cadmium, lead, and chromium. By integrating multiple advanced treatment technologies, this system achieves efficient purification and resource utilization of wastewater containing heavy metals, while reducing operating costs, thus possessing significant environmental and economic value. Background Technology

[0002] Wastewater from coal-fired power plants has a complex composition, containing high concentrations of suspended solids, organic matter, and heavy metal ions (such as Hg). 2+ Cd 2+ Pb 2 + Cr 6+ In existing technologies, traditional processes (such as chemical precipitation and single biological treatment) have the following drawbacks: low heavy metal removal efficiency; large sludge production, high disposal costs, and easy secondary pollution; high energy consumption and lack of resource recovery mechanisms. CN109650600A discloses an electrochemical-membrane coupled treatment system, but it does not solve the problems of sludge resource utilization and intelligent control; CN110563172A uses photocatalytic oxidation technology, but it does not integrate multi-stage synergistic oxidation and precise separation modules.

[0003] Traditional wastewater treatment processes suffer from low efficiency, unstable effluent parameters, and high energy consumption. In recent years, with the development of intelligent technologies, combining intelligent control systems with wastewater treatment processes has become a new research direction. Intelligent control systems can monitor various parameters during wastewater treatment in real time and automatically adjust the treatment process based on data feedback, thereby improving treatment efficiency, reducing energy consumption, and minimizing manual intervention. However, the market currently lacks a wastewater treatment system for heavy metal-containing wastewater that can deeply integrate multiple advanced treatment technologies with an intelligent control system. Therefore, this invention aims to fill this technological gap, urgently requiring a highly efficient, low-carbon, and intelligent integrated treatment solution. Utility Model Content

[0004] The purpose of this invention is to provide an integrated wastewater treatment system and method for heavy metal-containing wastewater, which integrates multiple advanced treatment technologies and intelligent control systems to achieve efficient purification and resource utilization of wastewater containing heavy metals.

[0005] The objective of this utility model can be achieved through the following technical solutions:

[0006] An integrated wastewater treatment system for coal-fired power plants containing heavy metals is provided. The system consists of an inlet connected in sequence to a grit chamber, a microfiltration membrane filter, an ozone catalytic oxidation unit, a photocatalytic oxidation unit, an electrochemical oxidation unit, an ion exchange unit, a magnetic nano-adsorption unit, and an anaerobic biological filter via a bar screen. The anaerobic biological filter is connected to a membrane bioreactor and a reverse osmosis system via an aerobic bioreactor.

[0007] In this utility model's technical solution, the output end of the upper part of the anaerobic biological filter is connected in sequence to the anaerobic digester and the sludge drying equipment via a sludge thickening tank.

[0008] In this utility model, the gas output end of the sludge anaerobic digester is connected to a biogas purification device, and the biogas purification device is connected to a generator set.

[0009] In this utility model, the distance between the anode and cathode of the electrochemical oxidation unit is 10-15 mm, and the electrolyte is wastewater containing 0.1-0.3 mol / L Na2SO4.

[0010] In this utility model, the sludge drying equipment is a solar-heat pump coupled drying system.

[0011] In this utility model, the photocatalytic oxidation unit uses a UV-C band ultraviolet lamp to excite the TiO2 nano-coating.

[0012] In the technical solution of this utility model, the reverse osmosis system adopts a multi-stage membrane module connected in series.

[0013] In this invention, the ultrafiltration membrane of the membrane bioreactor has a pore size of 0.01-0.1 μm.

[0014] The specific descriptions of each module in this practical new technology solution are as follows:

[0015] Physical filtration technology

[0016] 1. Bar screen: Mechanical or rotary bar screens are used to intercept large suspended particles (such as coal slag, fibers, etc.) to prevent blockage of subsequent equipment.

[0017] 2. Grit chamber: Removes heavy particles such as sand and metal shavings through gravity settling, reducing wear on pipes.

[0018] Microfiltration membrane filter: Uses microfiltration membranes with pore size of 0.1-10μm to intercept fine suspended solids and colloidal substances, reducing wastewater turbidity.

[0019] Multi-level synergistic oxidation module

[0020] 1. Ozone catalytic oxidation

[0021] Catalyst packing layer: Supported metal oxide catalysts (such as TiO2, Fe2O3) are used to work synergistically with ozone to decompose large molecular organic compounds (such as phenols and polycyclic aromatic hydrocarbons).

[0022] Ozone generator: generates ozone through high-voltage discharge or water electrolysis, with a dosage of 10-50 mg / L.

[0023] 2. Photocatalytic oxidation

[0024] Ultraviolet light emitting device: Uses UV-C band (200-280nm) ultraviolet lamps to excite photocatalysts (such as TiO2 nano-coatings) to generate active free radicals (·OH) to oxidize organic matter and heavy metal ions.

[0025] Photoreactor design: Use tubular or flat-plate reactors to ensure full contact between wastewater and catalyst.

[0026] 3. Electrochemical oxidation

[0027] Electrode materials: Titanium-based coated electrodes (such as Ti / RuO2-IrO2) or boron-doped diamond (BDD) electrodes are selected, and heavy metal ions (such as Cr) are enhanced through electrochemical reactions (anodic oxidation, cathodic reduction). 6+ →Cr 3+ The transformation and removal of ).

[0028] Current density control: Optimize current density (10-50 mA / cm²) 2 To balance oxidation efficiency and energy consumption.

[0029] Heavy metal ion precision separation module

[0030] 1. Ion exchange unit

[0031] Selective resins: Chelating resins (such as iminodiacetic acid resins) or thiourea resins are used to target specific heavy metals (Hg). 2+ Cd 2+ Pb 2+ To achieve highly selective adsorption.

[0032] Dynamic adsorption process: The flow rate (2-5 BV / h) is controlled in a fixed bed or fluidized bed reactor to improve the adsorption capacity.

[0033] 3. Magnetic nano-adsorption unit

[0034] Adsorbent preparation: Fe3O4@SiO2 core-shell structured magnetic nanoparticles were synthesized and their surface was modified with thiol (-SH) or amino (-NH2) functional groups to enhance their affinity for heavy metals.

[0035] Magnetic separation device: A high gradient magnetic field separator (HGMS) is used to quickly recover and recycle the adsorbent, reducing reagent consumption. The adsorbent dosage of the magnetic nano-adsorption unit (9) is 0.5-1.5 g / L, and the adsorbent can be recycled ≥10 times.

[0036] Bio-enhanced treatment module

[0037] 1. Anaerobic biological filter

[0038] Packing material selection: Use porous ceramsite or activated carbon as a biological carrier to enrich methanogenic bacteria (such as Methanosaeta) and acid-producing bacteria, decompose organic matter and produce biogas (CH4 content 60-70%).

[0039] Hydraulic retention time (HRT): Control the HRT to 12-24 hours to balance treatment efficiency and gas production.

[0040] 2. Aerobic bioreactor

[0041] Aeration system: Microporous aerators or jet aeration are used to maintain dissolved oxygen (DO) at 2-4 mg / L, which promotes the degradation of ammonia nitrogen by nitrifying bacteria (such as Nitrosomonas).

[0042] Biofilm technology: Forming a biofilm (such as polyurethane foam) on the surface of the filler to increase the amount of microbial adhesion and enhance the resistance to shock loads.

[0043] sludge resource utilization module

[0044] 1. Sludge thickening tank

[0045] Gravity thickener: Reduces sludge volume through natural settling (moisture content drops from 99% to 95%).

[0046] Centrifugal concentrator: A horizontal screw centrifuge is used to further reduce the moisture content to 90-92%.

[0047] 2. Sludge Anaerobic Digestion Tank

[0048] Mesophilic digestion process: Temperature controlled at 35-37℃, pH 6.8-7.2, and residence time 15-20 days, achieving an organic matter degradation rate >40%.

[0049] Biogas collection and purification: H2S is removed through a desulfurization tower (biological desulfurization or chemical absorption) to ensure biogas purity (CH > 55%).

[0050] 3. Sludge drying

[0051] Solar-powered drying sheds: Utilize natural light and ventilation to reduce the moisture content to 60-70%.

[0052] Thermal drying equipment: It adopts an indirect heat exchanger and uses biogas as a heat source to further dry the product to a moisture content of <30%.

[0053] Deep purification module

[0054] 1. Membrane Bioreactor (MBR)

[0055] Ultrafiltration membrane module: Polyvinylidene fluoride (PVDF) hollow fiber membrane with a pore size of 0.01-0.1μm is selected to retain microorganisms and colloidal substances.

[0056] Operating mode: Intermittent aeration (e.g., aeration for 10 minutes / pause for 2 minutes) is adopted to delay membrane fouling.

[0057] 2. Reverse Osmosis (RO) System

[0058] Multi-stage membrane module: brackish water membrane (low-pressure RO) and seawater membrane (high-pressure RO) in series, desalination rate >98%, effluent TDS <50mg / L.

[0059] Chemical cleaning: Regularly clean the membrane surface with citric acid or sodium hypochlorite to restore flux.

[0060] Energy recovery module

[0061] 1. Biogas power generation

[0062] Generator set: Select gas internal combustion engine or micro gas turbine, with cogeneration efficiency >35%.

[0063] Waste heat utilization: Recovering waste heat (such as hot water or steam) from generator sets for sludge drying or system insulation.

[0064] 2. Energy Management

[0065] Intelligent dispatching: Optimize power distribution through the energy management system (EMS) and prioritize power supply to high-energy-consuming units (such as RO systems).

[0066] All components involved in the above system can be achieved using existing technology or commercially available products to realize the purpose of this utility model.

[0067] The beneficial effects of this utility model are as follows:

[0068] Highly efficient removal of heavy metal ions

[0069] 1. Multi-stage synergistic oxidation: Through the synergistic effect of ozone catalytic oxidation, photocatalytic oxidation and electrochemical oxidation, it can efficiently decompose organic matter and heavy metal ions in wastewater, and significantly improve the removal efficiency of heavy metal ions;

[0070] 2. Precision separation technology: Utilizing ion exchange and magnetic nano-adsorption technology, heavy metal ions in wastewater are precisely separated and recovered, ensuring that the effluent quality consistently meets national discharge standards or reuse requirements.

[0071] Deep water purification

[0072] 4. Bio-enhanced treatment: Combining anaerobic biofilters and aerobic bioreactors, it deeply degrades organic matter in wastewater, removes pollutants such as ammonia nitrogen, and further purifies water quality.

[0073] 5. Deep purification module: Through membrane bioreactor (MBR) and reverse osmosis (RO) system, residual suspended solids and organic matter are further removed to ensure that the effluent water quality meets the high standard of reuse requirements.

[0074] Resource utilization and energy recovery

[0075] 1. Sludge Resource Utilization: Through sludge thickening, anaerobic digestion, and drying, sludge volume is reduced, achieving sludge reduction and resource utilization. The biogas produced from digestion can be used for power generation, reducing operating costs.

[0076] 2. Energy recovery: The biogas produced by the anaerobic digestion of sludge is used to generate electricity, providing energy support for part of the system's operation, achieving energy self-sufficiency, and further reducing operating costs.

[0077] Environmental friendliness and economy

[0078] 1. Reduce secondary pollution: By reducing the volume of sludge and utilizing it for resource recovery, the environmental pressure from sludge disposal can be reduced, and secondary pollution can be avoided.

[0079] 2. Reduced operating costs: Through energy recovery and resource utilization, the system's operating costs are significantly reduced, resulting in good economic efficiency.

[0080] 3. Water conservation: The treated water can be reused for industrial production or landscaping, reducing dependence on fresh water resources and alleviating water shortage problems.

[0081] Compact design and flexibility

[0082] 1. Modular design: The system adopts a modular design, which can be flexibly configured and expanded according to actual needs to adapt to the treatment needs of different scales and water qualities.

[0083] 2. Small footprint: The compact design makes the system occupy a small area, making it suitable for various complex water quality treatment scenarios.

[0084] Wide applicability

[0085] 1. Multiple application scenarios: The system is suitable for the treatment of various wastewater containing heavy metals, especially complex water quality treatment such as wastewater from coal-fired power plants, electroplating wastewater, and mining wastewater.

[0086] 2. High adaptability: The system can adapt to different influent water quality and treatment requirements, and has wide applicability and good scalability. Attached Figure Description

[0087] Figure 1 Schematic diagram of an integrated wastewater treatment system containing heavy metals

[0088] 1. Inlet, 2. Bar screen, 3. Grit chamber, 4. Microfiltration membrane filter, 5. Ozone catalytic oxidation unit, 6. Photocatalytic oxidation unit, 7. Electrochemical oxidation unit, 8. Ion exchange unit, 9. Magnetic nano-adsorption unit, 10. Anaerobic biological filter, 11. Aerobic bioreactor, 12. Sludge thickening tank, 13. Sludge anaerobic digestion tank, 14. Sludge drying equipment, 15. Membrane bioreactor (MBR), 16. Reverse osmosis (RO) system, 17. Biogas purification device, 18. Generator set, 19. Outlet. Detailed Implementation

[0089] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto:

[0090] like Figure 1 As shown, the integrated wastewater treatment system for heavy metals from a coal-fired power plant has an inlet 1 connected sequentially to a grit chamber 3, a microfiltration membrane filter 4, an ozone catalytic oxidation unit 5, a photocatalytic oxidation unit 6, an electrochemical oxidation unit 7, an ion exchange unit 8, a magnetic nano-adsorption unit 9, and an anaerobic biological filter 10 via a screen 2. The anaerobic biological filter 10 is connected to a membrane bioreactor 15 and a reverse osmosis system 16 via an aerobic bioreactor 11. The output end of the anaerobic biological filter 10 is connected sequentially to a sludge anaerobic digestion tank 13 and a sludge drying device 14 via a sludge thickening tank 12. The gas output end of the sludge anaerobic digestion tank 13 is connected to a biogas purification device 17, which is connected to a generator set 18. The anode and cathode distance of the electrochemical oxidation unit 7 is 10-15 mm. The sludge drying device 14 is a solar-heat pump coupled drying system. The photocatalytic oxidation unit 6 uses a UV-C band ultraviolet lamp to excite a TiO2 nano-coating. The reverse osmosis system 16 employs a multi-stage membrane module connected in series. The ultrafiltration membrane of the membrane bioreactor 15 has a pore size of 0.01-0.1 μm.

[0091] Working Principle: The system's workflow begins with wastewater entering through inlet 1. First, it passes through screen 2 to remove large suspended solids, then enters grit chamber 3 to remove heavy suspended solids such as sand. Next, it passes through microfiltration membrane filter 4 to further reduce turbidity. The pretreated wastewater then enters a multi-stage synergistic oxidation module. In ozone catalytic oxidation unit 5, ozone and catalysts decompose large organic molecules. Subsequently, in photocatalytic oxidation unit 6, ultraviolet light and photocatalysts further oxidize and decompose organic matter and heavy metal ions. Finally, electrochemical oxidation unit 7 enhances the oxidation-reduction reaction of heavy metal ions. The oxidized wastewater flows into a heavy metal ion precision separation module. In ion exchange unit 8, specific heavy metal ions are adsorbed by selective ion exchange resin, then enters magnetic nano-adsorption unit 9, where an external magnetic field and magnetic nano-adsorbents efficiently separate and recover heavy metal ions. After heavy metal ion separation, the wastewater enters a biological enhancement treatment module. In anaerobic biological filter 10, anaerobic microorganisms decompose organic matter and produce biogas. Then, in aerobic bioreactor 11, aerobic microorganisms further degrade organic matter and remove pollutants such as ammonia nitrogen. The sludge generated during the biological treatment process is sent to the sludge resource utilization module. In the sludge thickening tank 12, the sludge volume is reduced through gravity settling. The thickened sludge then enters the anaerobic digestion tank 13, where organic matter is decomposed under anaerobic conditions to produce biogas. The biogas is then purified by a purification device 17 to remove impurities before entering the generator set 18 to be converted into electrical energy, providing partial energy support for system operation. The digested sludge is then dried by a sludge drying device 14 to reduce its moisture content, achieving resource utilization. The deep purification module further ensures that the water quality meets standards. Wastewater first passes through a membrane bioreactor (MBR) 15 to remove residual suspended solids and organic matter, and then undergoes deep purification through a reverse osmosis (RO) system 16 to ensure that the effluent meets reuse standards.

[0092] Working Process: Wastewater first passes through an intelligent pretreatment module (bar screen, grit chamber, microfiltration membrane) to gradually remove large suspended solids, sand, and colloidal substances, reducing turbidity and providing stable water quality for subsequent treatment. It then enters a multi-stage synergistic oxidation module, where ozone catalytic oxidation decomposes large organic molecules, ultraviolet photocatalytic oxidation further degrades pollutants and converts heavy metals, and electrochemical oxidation enhances the redox reaction of heavy metals, making them easier to separate. The oxidized wastewater then enters a heavy metal ion precision separation module, where selective ion exchange resins adsorb specific heavy metals (such as mercury and cadmium), and magnetic nano-adsorbents rapidly separate and recover heavy metal ions under an external magnetic field, reducing residual pollution. The separated wastewater then enters a biological enhancement treatment module, where microorganisms in an anaerobic biological filter decompose organic matter and produce biogas, while an aerobic bioreactor further degrades remaining organic matter and removes ammonia nitrogen, achieving deep water purification. The sludge produced by biological treatment is concentrated, anaerobic digested (producing biogas), and dried, significantly reducing its volume and converting it into usable resources (such as building material raw materials). The biogas produced from sludge digestion is purified and used to drive a generator set. Part of the electricity is recycled for system operation (such as aeration and membrane cleaning), forming a self-sufficient energy closed loop. In the deep purification stage, the membrane bioreactor (MBR) retains suspended solids and microorganisms, and the reverse osmosis (RO) system desalinates and removes hardness, so that the final effluent meets industrial reuse or discharge standards.

[0093] This invention utilizes a synergistic process across the entire chain of "oxidative decomposition - precise separation - bio-enhancing - energy closed loop - intelligent regulation" to efficiently purify wastewater containing heavy metals into reusable water. Simultaneously, it achieves heavy metal recovery, sludge resource utilization, and energy self-sufficiency, providing an efficient, low-carbon, and economical integrated solution for industrial wastewater treatment.

[0094] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to preferred embodiments, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model's technical solution. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the content of the present utility model's technical solution shall still fall within the scope of the present utility model's technical solution.

[0095] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this utility model can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

Claims

1. An integrated wastewater treatment system for coal-fired power plants containing heavy metals, characterized in that, The inlet (1) is connected in sequence to the grit chamber (3), microfiltration membrane filter (4), ozone catalytic oxidation unit (5), photocatalytic oxidation unit (6), electrochemical oxidation unit (7), ion exchange unit (8), magnetic nano-adsorption unit (9) and anaerobic biological filter (10) through the bar screen (2); the anaerobic biological filter (10) is connected to the membrane bioreactor (15) and reverse osmosis system (16) through the aerobic bioreactor (11).

2. The integrated wastewater treatment system for heavy metal-containing coal-fired power plants according to claim 1, characterized in that, The upper output end of the anaerobic biological filter (10) is connected to the anaerobic digester (13) and the sludge drying equipment (14) in sequence through the sludge thickening tank (12).

3. The integrated wastewater treatment system for heavy metals from a coal-fired power plant according to claim 1, characterized in that, The gas output end of the sludge anaerobic digester (13) is connected to the biogas purification device (17), which is connected to the generator set (18).

4. The integrated wastewater treatment system for heavy metals from a coal-fired power plant according to claim 1, characterized in that, The distance between the anode and cathode in the electrochemical oxidation unit (7) is 10-15 mm.

5. The integrated wastewater treatment system for heavy metals from a coal-fired power plant according to claim 2, characterized in that, The sludge drying equipment (14) is a solar-heat pump coupled drying system.

6. The integrated wastewater treatment system for heavy metals from a coal-fired power plant according to claim 1, characterized in that, The photocatalytic oxidation unit (6) uses a UV-C band ultraviolet lamp to excite the TiO2 nano-coating.

7. The integrated wastewater treatment system for heavy metals from a coal-fired power plant according to claim 1, characterized in that, The reverse osmosis system (16) uses multi-stage membrane modules connected in series.

8. The integrated wastewater treatment system for heavy metals from a coal-fired power plant according to claim 1, characterized in that, The ultrafiltration membrane of the membrane bioreactor (15) has a pore size of 0.01-0.1 μm.

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