Combined treatment device for semi-coke wastewater

Abstract

The utility model discloses a combined treatment device for semi-coke wastewater, which comprises a pretreatment module, a two-stage biochemical module and an advanced oxidation module which are arranged in sequence, and a backwashing module is arranged on the advanced oxidation module; the two-stage biochemical module comprises a first-stage anaerobic tank, a first-stage aerobic tank and a first-stage sedimentation tank which are sequentially connected, a first-stage reflux pipeline is arranged on the first-stage sedimentation tank and connected to the first-stage anaerobic tank, and the output end of the first-stage sedimentation tank is connected with a second-stage anaerobic tank, a second-stage aerobic tank and a second-stage sedimentation tank which are sequentially arranged; a second-stage reflux pipeline is arranged on the second-stage sedimentation tank and is connected to the second-stage anaerobic tank; the advanced oxidation module comprises a catalytic ozonation device and an internal circulation biological aerated filter, and an ozone generator is arranged on one side of the catalytic ozonation device. According to the semi-coke wastewater treatment device, the biodegradability of semi-coke wastewater is improved, the property of the semi-coke wastewater is changed, and a good foundation is laid for subsequent operation through the stage.

Description

Technical Field

[0001] The utility model relates to the technical field of wastewater treatment devices, in particular to a combined treatment device for semi-coke wastewater. Background Art

[0002] Semi-coke wastewater, also known as semi-coke wastewater, is industrial wastewater generated during the medium- to low-temperature dry distillation (approximately 600-800°C) of low-grade coal (non-caking coal, slightly caking coal, and long-flame coal), as well as during gas purification and semi-coke steam quenching. This wastewater has a complex composition and contains a large number of difficult-to-degrade and highly toxic pollutants, including organic pollutants such as benzene, phenols, polycyclic aromatic hydrocarbons, and nitrogen-oxygen heterocyclic compounds, as well as inorganic pollutants such as heavy metals. It is a typical highly polluting and toxic industrial wastewater.

[0003] After the Ministry of Industry and Information Technology included lignite (semi-coke) in the industrial catalogue in 2008, the lignite industry has developed rapidly due to huge market demand. However, environmental workers have not kept up with the pace of research on lignite wastewater. Most lignite production enterprises that have been put into production still use ordinary biochemical treatment or incineration methods for wastewater treatment.

[0004] The carbonization furnaces currently used by semi-coke (or semi-coke) producers are primarily internally heated vertical furnaces. Because the tar and water produced in these vertical furnaces are difficult to separate, the wastewater has a COD of up to 30,000-40,000 mg / L and contains a large amount of toxic substances that inhibit microbial growth, making biochemical treatment difficult to meet standards. Incineration, due to its high energy consumption, is only suitable for small enterprises with limited water resources. Furthermore, during incineration, harmful substances in the wastewater are released into the atmosphere as vapor, causing secondary pollution.

[0005] At the same time, due to the incomplete oxidation of coal during the semi-coke production process, semi-coke wastewater contains a large amount of coal tar and low-molecular organic matter. The organic matter is of various types, including phenols, polycyclic aromatic hydrocarbons, benzene series, and heterocyclic compounds containing nitrogen, oxygen, and sulfur. It is a typical organic refractory industrial wastewater.

[0006] In the past, there was no mature lignite wastewater treatment process at home and abroad. The treatment method mainly borrowed from the coking wastewater treatment process with similar water quality. The typical treatment process flow includes oil removal process, phenol and ammonia recovery process, biochemical treatment process, deep treatment process, desalination treatment process and evaporation crystallization process.

[0007] However, the water quality of lignite wastewater is 10 times worse than that of coking wastewater, and the biodegradability of the wastewater is even worse. At the same time, various treatment processes currently have some serious problems in their promotion and application, such as high one-time investment cost, high operating costs, harsh reaction conditions, extractant poisoning, fouling or scaling, ammonia vapor pipeline blockage, and unstable operation. These are also problems that urgently need to be solved in the field of lignite wastewater treatment. Utility Model Content

[0008] The technical problem to be solved by the utility model is to provide a combined treatment device for semi-coke wastewater, which improves the biodegradability of semi-coke wastewater and changes the properties of semi-coke wastewater. After this stage, a good foundation is laid for subsequent operations.

[0009] In order to solve the above technical problems, the utility model provides a combined treatment device for semi-coke wastewater, comprising a pretreatment module, a two-stage biochemical module and an advanced oxidation module arranged in sequence, wherein the advanced oxidation module is provided with a backwash module; the two-stage biochemical module comprises a primary anaerobic tank, a primary aerobic tank and a primary sedimentation tank connected in sequence, the primary sedimentation tank is provided with a primary return pipe connected to the primary anaerobic tank, the output end of the primary sedimentation tank is connected to a secondary anaerobic tank, a secondary aerobic tank and a secondary sedimentation tank arranged in sequence, the secondary sedimentation tank is provided with a secondary return pipe connected to the secondary anaerobic tank; the advanced oxidation module comprises an ozone catalytic oxidation device and an internal circulation aerated biological filter, and an ozone generator is provided on one side of the ozone catalytic oxidation device.

[0010] Furthermore, the pretreatment module includes a grease trap and a hydrolysis tank, and the output end of the hydrolysis tank is connected to the primary anaerobic tank.

[0011] Furthermore, the backwash module includes an air compressor, and the air compressor is provided with a backwash gas pipeline connected to the ozone catalytic oxidation device and the internal circulation aerated biological filter.

[0012] Furthermore, a backwash water pipe is provided at the water outlet of the internal circulation biological aeration filter, and the backwash water pipe is connected to the bottom of the ozone catalytic oxidation device and the internal biological module of the internal circulation biological aeration filter.

[0013] Furthermore, coagulants and coagulant aids are added into the primary sedimentation tank and the secondary sedimentation tank.

[0014] Furthermore, the coagulant is polyferric sulfate and the flocculant is polyacrylamide.

[0015] Beneficial effects of the utility model: 1. The utility model patent adopts hydrolysis pretreatment and two-stage biochemical technology according to the characteristics of semi-coal wastewater;

[0016] 2. This new patent uses a process flow of ozone catalytic oxidation process + internal circulation aerated biological filter IRBAF + Fenton process to treat the high chroma and high content of difficult-to-degrade substances in semi-coke wastewater. It improves the biodegradability of semi-coke wastewater and changes its properties. After this stage, it lays a good foundation for subsequent operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1It is a schematic diagram of the overall structure of the utility model.

[0018] Explanation of the numbers in the figure: 1. Grease trap; 2. Hydrolysis tank; 3. Primary anaerobic tank; 4. Primary aerobic tank; 5. Primary sedimentation tank; 6. Primary return pipe; 7. Secondary anaerobic tank; 8. Secondary aerobic tank; 9. Secondary sedimentation tank; 10. Secondary return pipe; 11. Ozone catalytic oxidation device; 12. Internal circulation aerated biological filter; 13. Ozone generator; 14. Air compressor; 15. Backwash water pipe; 16. Backwash air pipe. DETAILED DESCRIPTION

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0022] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0023] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0024] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0025] Reference Figure 1 As shown, an embodiment of a combined treatment device for semi-coke wastewater of the present invention comprises a pretreatment module, a two-stage biochemical module and an advanced oxidation module arranged in sequence, and a backwash module is provided on the advanced oxidation module; the two-stage biochemical module comprises a primary anaerobic tank 3, a primary aerobic tank 4 and a primary sedimentation tank 5 connected in sequence, the primary sedimentation tank 5 is provided with a primary return pipe 6 connected to the primary anaerobic tank 3, the output end of the primary sedimentation tank 5 is connected to a secondary anaerobic tank 7, a secondary aerobic tank 8 and a secondary sedimentation tank 9 arranged in sequence, and the secondary sedimentation tank 9 is provided with a secondary return pipe 10 connected to the secondary anaerobic tank 7; the advanced oxidation module comprises an ozone catalytic oxidation device 11 and an internal circulation aerated biological filter 12, and an ozone generator 13 is provided on one side of the ozone catalytic oxidation device 11.

[0026] The pretreatment module includes a grease trap 1 and a hydrolysis tank 2, the output end of the hydrolysis tank 2 is connected to the primary anaerobic tank 3; the backwash module includes an air compressor 14, and the air compressor 14 is provided with a backwash gas pipe 16 connected to the ozone catalytic oxidation device 11 and the internal circulation aerated biological filter 12; the water outlet end of the internal circulation aerated biological filter 12 is provided with a backwash water pipe 15, and the backwash water pipe 15 is connected to the bottom of the ozone catalytic oxidation device 11 and the internal biological module of the internal circulation aerated biological filter 12; coagulant and flocculant aid are added to the primary sedimentation tank 5 and the secondary sedimentation tank 9, the coagulant is polyferric sulfate, and the flocculant is polyacrylamide.

[0027] During use, the semi-coke wastewater enters the hydrolysis tank 2 for pretreatment after oil removal pretreatment in the grease trap 1, and then enters the two-stage biochemical module again. After multiple experimental adjustments, the best effect is achieved when the overall residence time is 100 hours. In this stage, special bacterial agents are used. The strains contained in the bacterial agents have strong resistance to toxic pollutants such as chlorine, salt, cyanide, phenol, and sulfur, and have good degradation capabilities for pollutants such as organic matter, nitrogen, and phosphorus in the sewage.

[0028] After the effluent from the biochemical system, it is subjected to coagulation and sedimentation treatment. The coagulant and flocculant aid used are polyferric sulfate and PAM (polyacrylamide) respectively. After treatment by the biochemical system and coagulation and sedimentation, the water color changes significantly and the effluent COD is significantly reduced.

[0029] After the coagulation and sedimentation process, it enters the advanced oxidation treatment, using the ozone catalytic oxidation process. The porous inorganic material-supported catalyst used in the ozone catalytic oxidation technology produces hydroxyl radicals (·OH) by catalyzing ozone. The hydroxyl radical oxidation is non-selective and has high oxidation efficiency. The catalyst has the advantages of long catalyst service life and stable efficiency; less equipment, fewer control points, simple process and simple operation; low project investment and low operating costs. After treatment by this process, the semi-coke wastewater has basically become clear and the COD has dropped to less than 100mg / L.

[0030] After the previous several steps of process treatment, COD has been greatly reduced and the appearance of the wastewater has changed significantly, but the residual refractory COD in the water has not yet reached the discharge standard. The utility model adopts an internal circulation aerated biological filter 12 (IRBAF) plus Fenton process to treat the residual refractory COD. The main principle of the internal circulation aerated biological filter 12 IRBAF is developed on the basis of traditional biological aeration filter BAF technology. It overcomes the two bottleneck factors in the original BAF technology, namely: it overcomes the problem of unbalanced distribution of the three phases of gas, water and membrane in the original BAF, thereby improving the filler utilization rate of BAF; adopts a new backwashing technology to reduce backwashing energy consumption, improve backwashing efficiency, extend the backwashing cycle, and prevent the filler compaction phenomenon that is easy to occur in BAF when treating industrial wastewater, thereby further improving the working capacity of BAF. The characteristic of the technology is that by adopting new isolation aeration technology and lightweight, high-cavity and high-specific-surface-rate characteristic biological fillers, a large-flow internal circulation water flow is formed inside the biological filter. In this internal circulation flow, the biological filter material filler bed can utilize the characteristics of the sewage itself to quickly cultivate a superior microbial phase with good adaptability to the sewage, forming a biological oxidation bed with exclusive good performance. During long-term operation, it is supplemented by a proprietary technology of high-efficiency gas filter bed backwashing to maintain the activity of the biological phase, thereby forming a biological filter with high efficiency and good stability. In the process of this utility model, the overall residence time of this process section is less than 90 minutes, the COD decreases slightly, and the properties of the wastewater change, which lays a good foundation for the subsequent use of the Fenton process.

[0031] After adjusting the wastewater's properties using the internally circulating aerated biological filter (12IRBAF), it was treated using the Fenton process. The Fenton process is based on the principle that under acidic conditions, Fe2+ and H2O2 react to generate highly oxidizing hydroxyl radicals (·OH), which can oxidize and decompose difficult-to-degrade organic pollutants. The generated hydroxyl radicals (·OH) are the second strongest oxidants (E°=2.87V, relative to the normal hydrogen electrode (NHE), second only to fluoride (E°=3.06V). Hydroxyl radicals can rapidly react with various organic pollutants (RH) through hydrogen abstraction, electrophilic addition, and electron transfer, mineralizing them into CO2, H2O, and inorganic ions. Ultimately, the organic pollutants (RH) are completely degraded. In the final Fenton process, the wastewater becomes essentially colorless and transparent, the odor is significantly eliminated, and the COD drops to 40mg / L, meeting relevant emission standards.

[0032] In view of the poor biodegradability and high toxicity of lignite wastewater, this device proposes a biochemical treatment method of hydrolysis pretreatment plus secondary biochemical process. This treatment method slightly improves the biodegradability of lignite wastewater and changes its properties. After this stage, a good foundation is laid for subsequent processes.

[0033] The biodegradability of semi-coke wastewater is poor. In previous processes, after slightly improving the biodegradability of semi-coke wastewater, a series of deep treatment methods were used, which had a significant effect on difficult-to-degrade organic matter. The focus of this utility model process is mainly due to the poor biodegradability of semi-coke wastewater. If conventional biochemical processes are used to solve the biodegradability problem, large amounts of domestic sewage, sugars, and urea must be added to adjust the process, which invisibly increases operating costs. This semi-coke wastewater treatment device uses unique COD removal technology and equipment, mainly advanced oxidation + BAF + Fenton process, which can reduce COD values to 50mg / L, solving the problem without adjusting the front-end biodegradability. In comparison, it has significant advantages in both treatment capacity and operating costs.

[0034] The above-described embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are within the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

Claims

1. A combined treatment device for semi-coal wastewater, characterized in that: It comprises a pretreatment module, a two-stage biochemical module and an advanced oxidation module which are arranged in sequence, wherein the advanced oxidation module is provided with a backwash module; The two-stage biochemical module comprises a primary anaerobic tank (3), a primary aerobic tank (4) and a primary sedimentation tank (5) connected in sequence, the primary sedimentation tank (5) is provided with a primary return pipe (6) connected to the primary anaerobic tank (3), the output end of the primary sedimentation tank (5) is connected to a secondary anaerobic tank (7), a secondary aerobic tank (8) and a secondary sedimentation tank (9) arranged in sequence, and the secondary sedimentation tank (9) is provided with a secondary return pipe (10) connected to the secondary anaerobic tank (7); The advanced oxidation module comprises an ozone catalytic oxidation device (11) and an internal circulation aeration biological filter (12), and an ozone generator (13) is provided on one side of the ozone catalytic oxidation device (11).

2. The combined treatment device for blue carbon wastewater according to claim 1, characterized in that: The pretreatment module comprises a grease trap (1) and a hydrolysis tank (2), and the output end of the hydrolysis tank (2) is connected to the primary anaerobic tank (3).

3. The combined treatment device for blue carbon wastewater according to claim 1, characterized in that: The backwash module comprises an air compressor (14), and the air compressor (14) is provided with a backwash gas pipeline (16) connected to the ozone catalytic oxidation device (11) and the internal circulation aerated biological filter (12).

4. The combined treatment device for blue carbon wastewater according to claim 1, characterized in that: A backwash water pipe (15) is provided at the water outlet of the internal circulation biological aeration filter (12), and the backwash water pipe (15) is connected to the bottom of the ozone catalytic oxidation device (11) and the internal biological module of the internal circulation biological aeration filter (12).

5. The combined treatment device for semi-coal wastewater according to claim 1, characterized in that: Coagulant and flocculant are added into the primary sedimentation tank (5) and the secondary sedimentation tank (9).

6. The combined treatment device for semi-coal wastewater according to claim 5, characterized in that: The coagulant is polyferric sulfate, and the flocculant is polyacrylamide.

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