Sewage treatment device with low carbon nitrogen ratio
By combining electrocoagulation and MABR reactor technology, the problem of nitrogen and phosphorus removal in wastewater treatment with low C/N ratio was solved, achieving high-efficiency wastewater treatment and energy saving.
Patent Information
- Application Number
- CN202520010225.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-03
- Publication Date
- 2025-12-30
- Estimated Expiration
- 2035-01-03
AI Technical Summary
Low C/N ratios in urban wastewater lead to insufficient electron donors during microbial denitrification, limiting biological nitrogen removal performance. Furthermore, traditional biological processes struggle to achieve simultaneous nitrogen and phosphorus removal, increasing operating costs and excess sludge production.
A combined process of electrocoagulation reactor and membrane aerated bioreactor (MABR) was adopted to remove pollutants through electrocoagulation, control dissolved oxygen concentration, realize one-stage nitrification-anaerobic ammonia oxidation, construct a pure biofilm MABR system, and improve nitrogen removal efficiency.
It achieves efficient nitrogen and phosphorus removal from wastewater with low carbon-to-nitrogen ratio, reduces the production of residual sludge, lowers energy consumption, and simplifies the operation process.
Smart Images
Figure CN223737871U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of wastewater treatment technology, specifically relating to a wastewater treatment device with a low carbon-to-nitrogen ratio. Background Technology
[0002] Biological treatment processes have become the most commonly used technology in wastewater treatment plants worldwide due to their advantages such as strong adaptability to influent water quality, flexible operation, and stable process performance. However, due to the long-term use of low-cost combined sewer systems, urban wastewater in China often exhibits a low C / N ratio due to insufficient carbon sources. When the C / N ratio of wastewater is low, microorganisms lack electron donors during denitrification, limiting biological nitrogen removal performance and making it difficult to meet the standards for total nitrogen concentration in the effluent. Furthermore, due to electron competition between denitrifying and phosphorus-removing microorganisms, traditional biological processes struggle to achieve simultaneous nitrogen and phosphorus removal. The development goals of reducing excess sludge production, improving nitrogen and phosphorus removal efficiency, and saving energy and reducing consumption in wastewater treatment processes have also presented new challenges to the field of water pollution control, including technological innovation and operational cost control.
[0003] Electrocoagulation involves placing a metal electrode (iron or aluminum) in the water to be treated. Under the influence of an electric field, the metal anode undergoes an electrochemical reaction, releasing metal ions that hydrolyze in the water to generate hydroxyl complex flocculants, resulting in coagulation or flocculation. The electrocoagulation process is complex, involving simultaneous electrocoagulation, electroflotation, and electrooxidation. In electrocoagulation, the anode plate loses electrons after being energized, undergoing a series of hydrolysis reactions in the water to generate highly active flocculants with strong adsorption capacity. These flocculants adsorb and co-precipitate pollutants through adsorption bridging, charge neutralization, and entrapment. Electroflotation utilizes the air flotation effect created by microbubbles of H2 released from the cathode and O2 released from the anode during electrolysis, which carries flocs to the surface for removal. Electrooxidation primarily involves oxidation at the anode during electrolysis, which is beneficial for removing organic matter and inorganic reducing substances from wastewater and enhancing its biodegradability.
[0004] Partial nitrification-anaerobic ammonium oxidation is a fully autotrophic biological nitrogen removal process. Wastewater first undergoes nitrification, and part of the NH4+ is removed. + -N is oxidized to NO2 - -N, then the remaining NH4 + -N and the generated NO2 --N reactions produce N2. Compared to traditional biological nitrogen removal (nitrification / denitrification), the PN / A process can save approximately 60% of oxygen demand, 100% of carbon source addition, and 80% of excess sludge production. Despite the numerous advantages of the PN / A process, effectively inhibiting or eliminating nitrite-oxidizing bacteria to maintain stable nitrite production and reducing effluent TN concentration during domestic wastewater treatment remain key technical challenges in its mainstream application. A membrane aerated bioreactor (MABR) is used, with dissolved oxygen concentration controlled, to start and continuously operate a single-stage nitrite-anaerobic ammonium oxidation process using intermittent aeration. In this process, the MABR membrane module serves both as an oxygen mass transfer channel, directly supplying oxygen to microorganisms growing on the membrane surface, and as a carrier for microbial attachment. The counter-current mass transfer of oxygen and liquid pollutants creates an oxygen concentration gradient within the biofilm, achieving coexistence of aerobic and anaerobic environments within a single reactor and improving oxygen utilization efficiency. More importantly, membrane aeration facilitates control of the nitrite reaction and achieves a higher nitrogen removal load. Utility Model Content
[0005] In summary, this invention provides a wastewater treatment device with a low carbon-to-nitrogen ratio, mainly composed of an electrocoagulation reactor, a MABR reactor, a sedimentation tank, a DC power supply system, and an air supply system. The electrocoagulation reactor removes dissolved, colloidal, and suspended pollutants from the water through coagulation, oxidation, and flotation. The MABR reactor, by controlling the dissolved oxygen concentration, uses intermittent aeration to start and continuously operate a single-stage nitrification-anaerobic ammonium oxidation process. By constructing a pure biofilm MABR system, rapid start-up of the PN / A ratio is achieved, and the nitrogen removal capacity is gradually improved.
[0006] This utility model is achieved through the following technical solution:
[0007] The wastewater treatment device with a low carbon-to-nitrogen ratio is characterized by mainly consisting of an electrocoagulation reactor, a MABR reactor, a sedimentation tank, a DC power supply system, and an air supply system. The inlet is located at the front end of the electrocoagulation reactor, and the wastewater passes through the electrocoagulation reactor, the MABR reactor, and the sedimentation tank in sequence. The outlet is located at the end of the sedimentation tank. The DC power supply system consists of a DC power supply and wires, which provide stable electrical energy to the electrodes of the electrocoagulation reactor. The air supply system mainly consists of air supply equipment, a PLC controller, pipelines, valves, and pressure gauges, which supply air to the MABR reactor through pipelines.
[0008] The electrocoagulation reaction tank is equipped with several staggered anode plates and cathode plates;
[0009] The top of the MABR reactor is equipped with a cover plate with an exhaust port; the MABR reactor is equipped with a MABR membrane module, a membrane support, and a bottom aerator; the MABR membrane module is fixed on the membrane support; the bottom aerator receives the air outlet of the MABR membrane module through a pipe and adjusts the air volume using a first valve.
[0010] 20%-50% of the sludge in the sedimentation tank flows into the MABR reactor through a sludge return pump, while 50%-80% of the remaining sludge is discharged.
[0011] Furthermore, the positive terminal of the DC power supply is connected to the anode plate, and the negative terminal is connected to the cathode plate. Both the anode plate and the cathode plate are made of aluminum.
[0012] Furthermore, the PLC controller is connected to the air supply equipment and controls the opening and closing of the air supply equipment through a built-in timer, thereby controlling the aeration time. The opening time: closing time ratio is 0.5:1-1.5:1.
[0013] Furthermore, the gas supply equipment is connected to the MABR membrane module of the MABR reactor via a pipeline, a second valve, and a pressure gauge, and the gas supply volume is adjusted by the second valve.
[0014] This invention discloses a wastewater treatment device with a low carbon-to-nitrogen ratio. The electrocoagulation reactor removes dissolved, colloidal, and suspended pollutants from the water through coagulation, oxidation, and flotation. A MABR reactor is employed, and by controlling the dissolved oxygen concentration, a single-stage nitrification-anaerobic ammonium oxidation process is started and continuously operated via intermittent aeration. By constructing a pure biofilm MABR system, rapid start-up of the PN / A ratio is achieved, and the nitrogen removal capacity is gradually increased. This device has advantages such as simple structure, ease of operation, low sludge production, and good wastewater treatment effect. Attached Figure Description
[0015] Appendix Figure 1 This is a schematic diagram of the elevation structure of this utility model.
[0016] In the diagram: 1. DC power supply, 2. Inlet, 3. Electrocoagulation reactor, 4. Anode plate, 5. Cathode plate, 6. First valve, 7. PLC controller, 8. Air supply equipment, 9. Second valve, 10. Pressure gauge, 11. Cover plate, 12. MABR reactor, 13. Exhaust port, 14. MABR membrane module, 15. Bottom aerator, 16. Membrane support, 17. Sedimentation tank, 18. Outlet, 19. Sludge return pump. Detailed Implementation
[0017] To make the technical means, creative features, objectives, and effects of this utility model easier to understand, please refer to... Figure 1 The present invention will be further described below with reference to specific embodiments.
[0018] A wastewater treatment device with a low carbon-to-nitrogen ratio mainly consists of an electrocoagulation reactor 3, a MABR reactor 12, a sedimentation tank 17, a DC power supply system, and an air supply system. The inlet 2 is located at the front end of the electrocoagulation reactor 3, through which wastewater sequentially passes. The outlet 18 is located at the end of the sedimentation tank 17. The DC power supply system, consisting of a DC power supply 1 and wires, provides stable electrical energy to the electrodes of the electrocoagulation reactor 3. The air supply system mainly includes an air supply device 8, a PLC controller 7, pipes, valves, and a pressure gauge 10, supplying air to the MABR reactor 12 via pipes. 2. Gas supply; The electrocoagulation reactor 3 is equipped with several staggered anode plates 4 and cathode plates 5; The top of the MABR reactor is equipped with a cover plate 11, and the cover plate is equipped with an exhaust hole 13; The MABR reactor 12 is equipped with a MABR membrane module 14, a membrane support 16 and a bottom aerator 15; The MABR membrane module 14 is fixed on the membrane support 16; The bottom aerator 15 receives the air outlet of the MABR membrane module 14 through a pipeline and adjusts the air volume with a first valve 6; 20%-50% of the sludge in the sedimentation tank 17 flows into the MABR reactor 12 through the sludge return pump 19, and 50%-80% of the remaining sludge is discharged.
[0019] The DC power supply 1 is connected to the anode plate 4 at its positive terminal and to the cathode plate 5 at its negative terminal. Both the anode plate 4 and the cathode plate 5 are made of aluminum. The PLC controller 7 is connected to the air supply device 8 and controls the opening and closing of the air supply device 8 through a built-in timer to control the aeration time. The opening time: closing time is 0.5:1-1.5:1. The air supply device 8 is connected to the MABR membrane module 14 of the MABR reactor 12 through a pipeline, a second valve 9 and a pressure gauge 10. The amount of air supplied is adjusted through the second valve 9.
[0020] The process flow of this utility model is as follows: wastewater is pumped into the electrocoagulation reactor 3 through the inlet 2, where coagulation, oxidation, and flotation are carried out to remove dissolved, colloidal, and suspended pollutants from the water. The effluent from the electrocoagulation reactor 3 enters the MABR reactor 12, where a single-stage nitrification-anaerobic ammonia oxidation process is started and continuously operated by intermittent aeration to remove nitrogen and carbon by controlling the dissolved oxygen concentration. The effluent from the MABR reactor 12 flows into the sedimentation tank 17 for solid-liquid separation and is then discharged from the outlet 18. Part of the sludge from the sedimentation tank 17 is returned to the MABR reactor 12, and the remaining sludge is discharged.
[0021] The above embodiments are merely illustrative of the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope of this utility model, based on its technical solution and concept, should be included within the scope of protection of this utility model.
Claims
1. A low carbon to nitrogen ratio sewage treatment apparatus characterised in that: The device mainly comprises an electric flocculation reaction tank, an MABR reaction tank, a sedimentation tank, a direct current power supply system and a gas supply system, the water inlet is arranged at the front end of the electric flocculation reaction tank, the sewage sequentially passes through the electric flocculation reaction tank, the MABR reaction tank and the sedimentation tank, the water outlet is arranged at the end of the sedimentation tank, the direct current power supply system is composed of a direct current power supply and a wire, and provides stable electric energy for the electrode of the electric flocculation reaction tank, and the gas supply system mainly comprises a gas supply device, a PLC controller, a pipeline, a valve and a pressure gauge, and the pipeline is used for supplying gas to the MABR reaction tank. The electric flocculation reaction tank is internally provided with a plurality of staggered and spaced anode plates and cathode plates. The MABR reaction tank is provided with a cover plate at the top, and the cover plate is provided with an exhaust hole; the MABR reaction tank is internally provided with an MABR membrane assembly, a membrane support and a bottom aerator; the MABR membrane assembly is fixed on the membrane support; the bottom aerator receives the gas outlet end of the MABR membrane assembly through the pipeline, and the amount of gas is adjusted by the first valve. 20%-50% of the sludge in the sedimentation tank flows into the MABR reaction tank through a sludge backflow pump, and 50%-80% of the remaining sludge is discharged.
2. A low C:N ratio sewage treatment apparatus according to claim 1, characterised in that: The positive electrode of the direct current power supply is connected with the anode plate, and the negative electrode is connected with the cathode plate; the anode plate and the cathode plate are both aluminum electrode plates.
3. The low C:N ratio sewage treatment device according to claim 1, characterized by: The PLC controller is connected with the gas supply device, and the opening and closing of the gas supply device are controlled by the built-in timer to control the aeration time; the opening time is 0.5:1-1.5:1 of the closing time.
4. The low C:N ratio sewage treatment device according to claim 1, characterized by: The gas supply device is connected with the MABR membrane assembly of the MABR reaction tank through the pipeline, the second valve and the pressure gauge, and the amount of gas supply is adjusted by the second valve.