An anaerobic reactor for treating chromium-containing wastewater

Abstract

This utility model belongs to the field of wastewater treatment technology, and particularly relates to an anaerobic reactor for treating chromium-containing wastewater, comprising: a pretreatment component for introducing and pretreating chromium wastewater; a spray system disposed within the pretreatment component for circulating and spraying the chromium wastewater within the pretreatment component; an anaerobic treatment component, with its inlet end connected to the outlet end of the pretreatment component and its outlet end connected to the inlet end of the pretreatment component; a circulation component disposed within the anaerobic treatment component for circulating the chromium wastewater within the anaerobic treatment component; and a sedimentation component, with its inlet end connected to the outlet end of the anaerobic treatment component. This utility model solves the problems of high sludge production and high total chromium effluent index in the original process of removing total chromium and hexavalent chromium using chemical precipitation.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, and in particular relates to an anaerobic reaction device for treating chromium-containing wastewater. Background Technology

[0002] Chromium (Cr) is a common pollutant, primarily originating from electroplating, mining, wood preservation, and the leather tanning industry. Cr exists in the environment mainly in two forms: hexavalent chromium (Cr(VI)) and trivalent chromium (Cr(III)). Trivalent chromium exists in water as CrO. 2- Cr 3+ Hexavalent chromium is represented as Cr2O7. 2- and CrO4 2- Chromium ions are highly mobile and toxic; if chromium-containing wastewater is improperly treated and discharged into the environment, it poses a serious threat to human health and the ecological environment. Currently, most methods for treating chromium-containing wastewater involve chemical precipitation to remove total chromium and hexavalent chromium, resulting in sludge containing large amounts of organic matter and generating a massive amount of hazardous waste.

[0003] Therefore, it is necessary to design an anaerobic reactor for treating chromium-containing wastewater to solve the above problems. Utility Model Content

[0004] The purpose of this invention is to provide an anaerobic reactor for treating chromium-containing wastewater, in order to solve the problems of large sludge production and high total chromium effluent index caused by the original process of removing total chromium and hexavalent chromium by adding chemicals and precipitation.

[0005] To achieve the above objectives, this utility model provides the following solution: an anaerobic reactor for treating chromium-containing wastewater, comprising:

[0006] A pretreatment component for introducing and pretreating chromium wastewater;

[0007] A spraying system is installed within the pretreatment assembly, the spraying system being used to circulate and spray chromium wastewater within the pretreatment assembly.

[0008] The anaerobic treatment component has its inlet end connected to the outlet end of the pretreatment component, and its outlet end connected to the inlet end of the pretreatment component.

[0009] A circulation component is provided within the anaerobic treatment component, the circulation component being used to circulate the chromium wastewater within the anaerobic treatment component.

[0010] The sedimentation component has its inlet end connected to the outlet end of the anaerobic treatment component.

[0011] According to this utility model, an anaerobic reactor for treating chromium-containing wastewater includes a pretreatment component comprising a pretreatment tower filled with packing material. The pretreatment tower is provided with a first air inlet, a first water inlet, and a first water outlet. The air outlet of the anaerobic treatment component is connected to the pretreatment tower through the first air inlet. An aeration system is also provided inside the pretreatment tower, located below the packing material and connected to the first air inlet. The first water inlet is located above the packing material, and the first water outlet is located below the packing material and connected to the liquid inlet of the anaerobic treatment component. A first discharge outlet is provided at the bottom of the pretreatment tower, and a first gas collection section is provided at the top of the pretreatment tower.

[0012] According to this utility model, an anaerobic reaction device for treating chromium-containing wastewater is provided, wherein the inlet end of the spray system is located below the packing material, and the outlet end of the spray system is located above the packing material.

[0013] According to the present invention, an anaerobic reaction device for treating chromium-containing wastewater is provided. The first gas collection section includes a first gas collection device, which is connected to the top of the pretreatment tower. The first gas collection device is provided with a first gas outlet.

[0014] According to this utility model, an anaerobic reactor for treating chromium-containing wastewater includes an anaerobic treatment tower filled with anaerobic sludge. A second inlet is located at the bottom of the anaerobic treatment tower and communicates with a first outlet. A second gas collection section is located at the top of the anaerobic treatment tower and communicates with the first gas inlet. A circulation component is located inside the anaerobic treatment tower, and a second outlet is also located at the top of the anaerobic treatment tower.

[0015] According to the present invention, an anaerobic reactor for treating chromium-containing wastewater is provided. The second gas collection section includes a second gas collection device, which is connected to the top of the anaerobic treatment tower. The second gas collection device is provided with a second gas outlet, which is connected to the first gas inlet.

[0016] According to this utility model, an anaerobic reactor for treating chromium-containing wastewater includes a circulation component comprising a circulation system and a reflux device. The reflux device is disposed within the anaerobic sludge, and its outlet is connected to a three-phase separator. The three-phase separator is disposed above the interior of the anaerobic treatment tower. The inlet of the circulation system is located at the bottom of the anaerobic sludge, and the outlet of the circulation system is located above the three-phase separator.

[0017] According to the present invention, an anaerobic reaction device for treating chromium-containing wastewater is provided. The precipitation component includes a precipitation tower, which is provided with a third inlet and a third outlet. The third inlet is connected to the second outlet, and a second discharge outlet is provided at the bottom of the precipitation tower.

[0018] Compared with the prior art, the present invention has the following advantages and technical effects:

[0019] This invention employs an anaerobic process to treat chromium-containing wastewater separately. Organic matter is converted into biogas containing hydrogen sulfide. Pretreatment reduces hexavalent chromium to trivalent chromium, which is then removed in the anaerobic reactor. This reduces the amount of hazardous chromium sludge and lowers treatment costs. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall design of this utility model.

[0022] The components are as follows: 1. First air inlet; 2. Aeration system; 3. First water inlet; 4. Packing material; 5. Spray system; 6. First air collection device; 7. First air outlet; 8. First discharge outlet; 9. First water outlet; 10. Second water inlet; 11. Circulation system; 12. Second air collection device; 13. Second air outlet; 14. Three-phase separator; 15. Reflux device; 16. Anaerobic sludge; 17. Second water outlet; 18. Third water inlet; 19. Third water outlet; 20. Second discharge outlet. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Reference Figure 1 As shown, this utility model provides an anaerobic reactor for treating chromium-containing wastewater, comprising:

[0026] A pretreatment component for introducing and pretreating chromium wastewater;

[0027] Spray system 5 is installed inside the pretreatment component. Spray system 5 is used to circulate and spray chromium wastewater inside the pretreatment component.

[0028] The anaerobic treatment component has its inlet end connected to the outlet end of the pretreatment component, and its outlet end connected to the inlet end of the pretreatment component.

[0029] A circulation component is installed inside the anaerobic treatment component. The circulation component is used to circulate the chromium wastewater within the anaerobic treatment component.

[0030] The inlet of the sedimentation unit is connected to the outlet of the anaerobic treatment unit.

[0031] Furthermore, the pretreatment component includes a pretreatment tower, which is filled with packing material 4. The pretreatment tower is provided with a first air inlet 1, a first water inlet 3, and a first water outlet 9. The air outlet of the anaerobic treatment component is connected to the pretreatment tower through the first air inlet 1. An aeration system 2 is also provided in the pretreatment tower. The aeration system 2 is located below the packing material 4 and is connected to the first air inlet 1. The first water inlet 3 is located above the packing material 4. The first water outlet 9 is located below the packing material 4 and is connected to the liquid inlet of the anaerobic treatment component. A first discharge outlet 8 is opened at the bottom of the pretreatment tower, and a first gas collection section is provided at the top of the pretreatment tower.

[0032] The liquid level inside the pretreatment tower is located between the first outlet 9 and the packing 4.

[0033] Furthermore, the inlet of the spray system 5 is located below the packing 4, and the outlet of the spray system 5 is located above the packing 4.

[0034] Furthermore, the first gas collection section includes a first gas collection device 6, which is connected to the top of the pretreatment tower, and a first gas outlet 7 is provided on the first gas collection device 6.

[0035] Furthermore, the anaerobic treatment component includes an anaerobic treatment tower, which is filled with anaerobic sludge 16. A second inlet 10 is provided at the bottom of the anaerobic treatment tower and is connected to a first outlet 9. A second gas collection section is provided at the top of the anaerobic treatment tower and is connected to a first air inlet 1. A circulation component is provided inside the anaerobic treatment tower, and a second outlet 17 is also provided at the top of the anaerobic treatment tower.

[0036] The liquid level inside the anaerobic treatment tower is located above the second outlet 17.

[0037] Furthermore, the second gas collection section includes a second gas collection device 12, which is connected to the top of the anaerobic treatment tower. The second gas collection device 12 is provided with a second gas outlet 13, which is connected to the first gas inlet 1.

[0038] Furthermore, the circulation component includes a circulation system 11 and a reflux device 15. The reflux device 15 is disposed within the anaerobic sludge 16. The outlet end of the reflux device 15 is connected to a three-phase separator 14, which is disposed above the interior of the anaerobic treatment tower. The inlet end of the circulation system 11 is located at the bottom of the anaerobic sludge 16, and the outlet end of the circulation system 11 is located above the three-phase separator 14.

[0039] Furthermore, the sedimentation assembly includes a sedimentation tower, which is provided with a third inlet 18 and a third outlet 19. The third inlet 18 is connected to the second outlet 17, and a second discharge outlet 20 is provided at the bottom of the sedimentation tower.

[0040] The liquid level inside the sedimentation tower is located above the third outlet 19.

[0041] The process flow of this utility model is as follows:

[0042] The anaerobic treatment tower produces biogas containing hydrogen sulfide. This biogas then enters the pretreatment tower, where, under the action of aeration system 2 and spray system 5, the chromium water and hydrogen sulfide react thoroughly, completely converting hexavalent chromium in the water into trivalent chromium. The biogas still contains a small amount of hydrogen sulfide, which can be utilized as a resource after desulfurization in the alkali scrubbing tower. The pretreated chromium water then enters the anaerobic treatment tower, where a biological reaction occurs to remove organic matter and produce biogas. Simultaneously, trivalent chromium is removed through biotransformation and fixation by anaerobic microorganisms, as well as co-precipitation and adsorption. The biologically treated chromium water then enters the sedimentation tower for further treatment. Alkali is added to adjust the pH to 8-10, completely precipitating the remaining trivalent chromium before the precipitate is discharged, reducing the total chromium in the water to below 0.5 mg / L.

[0043] Cr(VI) is significantly toxic to microorganisms in bioreactors, far exceeding the toxicity of Cr(III). It severely inhibits microbial activity and metabolic function; when the Cr(VI) concentration exceeds 1 mg / L, the respiration rate of activated sludge may decrease by more than 50%. Therefore, pretreatment of chromium-containing wastewater before it enters the anaerobic treatment tower is necessary to ensure the complete conversion of Cr(VI) to Cr(III), reducing the toxicity of the wastewater and protecting the activity and ecological function of the sludge microorganisms. In the pretreatment tower, H2S gas reacts with Cr(VI) ions in a redox reaction to form elemental sulfur precipitate. The chemical reaction equation is as follows: 2Cr 6+ +3S 2- →2Cr 3+ +3S↓.

[0044] During the metabolism of anaerobic sludge 16 in the anaerobic treatment tower, SO4 is utilized. 2- As an electron acceptor, it uses organic matter as a carbon source and electron donor for cellular synthesis, producing hydrogen sulfide gas. The chemical reaction equation is as follows: In the equation, the reaction condition 'm' above the equal sign represents the SRB bacterial community. This process consumes a large amount of organic matter. Simultaneously, the microbial cell surfaces in anaerobic sludge 16 contain numerous negatively charged functional groups, such as hydroxyl, carboxyl, and amino groups, which can bind to Cr(III) in the solution through electrostatic interactions and ion exchange, adsorbing it onto the cell surface. Furthermore, the EPS in anaerobic sludge 16 contains polysaccharides and proteins, which can combine with Cr(III) to form complexes and further induce precipitation. Simultaneously, some anaerobic microorganisms, such as certain sulfate-reducing bacteria and methanogens, can convert Cr(III) into a more stable form through enzymatic reactions, or bind it to intracellular substances, fixing it within the cell or sludge structure. Through the synergistic effect of these mechanisms, most of the Cr(III) can be removed in the anaerobic treatment tower.

[0045] The precipitation tower is a deep purification device to ensure complete removal of Cr(III). The chemical reaction equation is as follows: Cr 3+ +3OH - →Cr(OH)3↓.

[0046] The pretreatment tower, anaerobic treatment tower, and sedimentation tower are used in series to simultaneously remove hydrogen sulfide gas from biogas and chromium ions from chromium sludge. This also significantly reduces the production of hazardous chromium sludge.

[0047] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0048] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements to the technical solutions of the present utility model made by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope of the present utility model.

Claims

1. An anaerobic reactor for treating chromium-containing wastewater, characterized in that, include: A pretreatment component for introducing and pretreating chromium wastewater; A spray system (5) is provided in the pretreatment assembly, and the spray system (5) is used to circulate and spray chromium wastewater in the pretreatment assembly. The anaerobic treatment component has its inlet end connected to the outlet end of the pretreatment component, and its outlet end connected to the inlet end of the pretreatment component. A circulation component is provided within the anaerobic treatment component, the circulation component being used to circulate the chromium wastewater within the anaerobic treatment component. The sedimentation component has its inlet end connected to the outlet end of the anaerobic treatment component.

2. The anaerobic reactor for treating wastewater containing chromium according to claim 1, wherein The pretreatment component includes a pretreatment tower, which is filled with packing material (4). The pretreatment tower is provided with a first air inlet (1), a first water inlet (3), and a first water outlet (9). The air outlet of the anaerobic treatment component is connected to the pretreatment tower through the first air inlet (1). The pretreatment tower is also provided with an aeration system (2). The aeration system (2) is located below the packing material (4) and is connected to the first air inlet (1). The first water inlet (3) is located above the packing material (4). The first water outlet (9) is located below the packing material (4) and is connected to the liquid inlet of the anaerobic treatment component. The bottom of the pretreatment tower is provided with a first discharge outlet (8). The top of the pretreatment tower is provided with a first gas collection section.

3. The apparatus according to claim 2, wherein the apparatus is characterized by: The inlet end of the spray system (5) is located below the packing (4), and the outlet end of the spray system (5) is located above the packing (4).

4. The anaerobic reactor for treating wastewater containing chromium according to claim 2, wherein The first gas collection section includes a first gas collection device (6), which is connected to the top of the pretreatment tower, and a first gas outlet (7) is provided on the first gas collection device (6).

5. The anaerobic reactor for treating wastewater containing chromium according to claim 2, wherein The anaerobic treatment component includes an anaerobic treatment tower, which is filled with anaerobic sludge (16). A second inlet (10) is provided at the bottom of the anaerobic treatment tower and is connected to the first outlet (9). A second gas collection section is provided at the top of the anaerobic treatment tower and is connected to the first air inlet (1). The circulation component is provided inside the anaerobic treatment tower. A second outlet (17) is also provided at the top of the anaerobic treatment tower.

6. The anaerobic reactor for treating wastewater containing chromium according to claim 5, wherein The second gas collection section includes a second gas collection device (12), which is connected to the top of the anaerobic treatment tower. The second gas collection device (12) is provided with a second gas outlet (13), which is connected to the first gas inlet (1).

7. The apparatus according to claim 5, wherein the apparatus is characterized by: The circulation assembly includes a circulation system (11) and a reflux device (15). The reflux device (15) is located inside the anaerobic sludge (16). The outlet end of the reflux device (15) is connected to a three-phase separator (14). The three-phase separator (14) is located inside the anaerobic treatment tower. The inlet end of the circulation system (11) is located at the bottom of the anaerobic sludge (16), and the outlet end of the circulation system (11) is located above the three-phase separator (14).

8. The apparatus according to claim 5, wherein the apparatus is characterized by: The precipitation assembly comprises a precipitation tower, a third water inlet (18) and a third water outlet (19) are arranged on the precipitation tower, the third water inlet (18) is communicated with the second water outlet (17), and a second discharge port (20) is arranged at the bottom end of the precipitation tower.

Images