High-density continuous flow biological membrane sewage treatment device and treatment method

Abstract

The invention discloses a high-density continuous flow biological membrane sewage treatment device and a treatment method, and belongs to the technical field of sewage treatment. The device comprises an anaerobic tank, a sedimentation tank, an aerobic tank, an anoxic tank and an efficient sedimentation tank which are communicated in sequence. The system is characterized in that the aerobic tank and the anoxic tank are filled with suspended biological filler with a high filling ratio, and a filler intercepting device capable of vertically lifting is arranged above the filler. The treatment method comprises the steps of anaerobic treatment, precipitation, aerobic treatment, anoxic treatment, efficient precipitation and unique regular flushing maintenance. The problems that a traditional biological membrane process is large in occupied area, high in energy consumption and prone to blockage of filler are solved, an internal carbon source is enriched through sludge backflow, nitrification liquid backflow is omitted, and the aims of being compact in structure, efficient in nitrogen and phosphorus removal, stable in operation and easy and convenient to maintain are achieved.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection technology, and particularly relates to the field of wastewater treatment technology, specifically to a high-density continuous flow biofilm wastewater treatment device and its supporting process method. Background Technology

[0002] With the acceleration of urbanization and the increasing scarcity of land resources, traditional above-ground wastewater treatment plants face numerous challenges, including difficulties in site selection, high construction costs, and sensitivity to environmental impacts. Against this backdrop, underground wastewater treatment plants (WWTPs) are gradually becoming an important trend in urban wastewater treatment development due to their significant advantages such as land conservation, environmental friendliness, and landscape harmony. However, currently constructed underground wastewater treatment plants mostly adopt integrated layouts of traditional processes such as AAO and its modified versions, MBR, MBBR, CASS, CAST, and oxidation ditches. These solutions have not fundamentally solved the problems of large land area and high energy consumption in biological treatment units.

[0003] The aforementioned processes commonly used in existing underground wastewater treatment plants generally suffer from drawbacks such as long process flows, large footprints, high energy consumption, the need for additional carbon sources to achieve efficient denitrification, and high sludge production. In particular, the biological treatment unit typically accounts for 40% to 50% of the total land area of ​​the entire wastewater treatment plant, directly leading to high civil engineering costs. Especially for biofilm technologies (such as MBBR and IFAS) aimed at improving treatment efficiency, they generally face challenges such as low packing density, easy clogging, and even maintenance shutdowns, which severely restricts their application in high-standard, compact wastewater treatment projects. Therefore, in the promotion and application of underground wastewater treatment plants, there is an urgent need to develop a new type of wastewater treatment process and device that is more compact in structure, stable and reliable in operation, energy-efficient, easy to maintain, and capable of achieving high-standard effluent. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing sewage treatment devices, such as large footprint, high energy consumption, and easy clogging of packing materials, and to provide a high-density continuous flow biofilm sewage treatment device and treatment method that is compact, energy-efficient, produces low sludge, operates stably, and is easy to maintain.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A high-density continuous flow biofilm wastewater treatment device includes a main treatment facility and an aeration system. The main treatment facility comprises an anaerobic tank, a sedimentation tank, an aerobic tank, an anoxic tank, and a high-efficiency sedimentation tank, all connected sequentially by water flow, along with supporting aeration, flushing, and sludge return systems. Suspended biological packing material is installed in the aerobic and anoxic tanks, with corresponding aerobic and anoxic tank packing material interception devices installed above the packing material. Crucially, both the aerobic and anoxic tank packing material interception devices are vertically liftable structures, designed to be raised during flushing to expand the activity space of the suspended biological packing material, thereby achieving efficient in-situ fluidized bed flushing. These interception devices not only prevent packing material loss but are also the core mechanism enabling controllable switching between two states: normal operation of the biofilm reactor in a "high-density fixed bed" and efficient flushing in a "fully fluidized bed."

[0007] Furthermore, the anaerobic tank is equipped with a submersible mixer to maintain uniform mixing of mud and water in the tank, and its hydraulic retention time is designed to be 2 to 3 hours.

[0008] Furthermore, the sedimentation tank can be a horizontal flow, vertical flow, or radial flow sedimentation tank, preferably a rectangular horizontal flow sedimentation tank, equipped with a chain scraper and sludge return system, and its surface hydraulic load is designed to be ≤1.3m³ / (m².h).

[0009] Furthermore, the sludge return system includes a sludge pump and a return pipeline, used to return the sludge from the sedimentation tank to the front end of the anaerobic tank at a return ratio of 50% to 100%; the remaining sludge is discharged to the sludge thickening tank through the remaining sludge pipe.

[0010] Furthermore, the aerobic tank is provided with an aeration system, a water distribution device, suspended biological filler, an aerobic tank filler interception device, and an outlet trough in sequence from bottom to top.

[0011] Furthermore, the aeration device consists of a main air supply pipe and several perforated aeration branch pipes. The aeration pipes are evenly arranged at the bottom of the pool, with an opening diameter of 2-4 mm to ensure the formation of fine bubbles and an oxygen transfer efficiency of ≥27%. The air supply is provided by a blower.

[0012] Furthermore, the water distribution device is located above the aeration system and consists of a water distribution channel and a perforated water distribution pipe. The perforated water distribution pipe has an opening diameter of 15-20 mm, which is evenly distributed in a quincunx pattern. The flow velocity through the perforations is designed to be controlled at 0.1-0.3 m / s to ensure that the incoming water is evenly distributed across the cross-section of the tank.

[0013] Furthermore, the suspended biological packing material can be selected from spherical porous packing materials, cylindrical or rectangular porous packing materials, etc., with a specific surface area ≥650m² / m³ and a filling ratio as high as 75%~85%. The type of packing material and the filling ratio can be selected according to the specific water quality of the influent.

[0014] Furthermore, the aerobic tank packing interception device is hydraulically adjustable, located above the packing layer, and consists of a horizontal interception screen, a lifting frame, and a hydraulic system. The hydraulic system can drive the entire interception screen to be vertically lifted to a certain height (usually 1.0 to 1.5 meters). The opening diameter of the horizontal interception screen is 15 to 20 mm, and the flow velocity through the opening is controlled at 0.05 to 0.1 m / s during normal operation.

[0015] Furthermore, the main structure of the anoxic tank is similar to that of the aerobic tank, and also includes a flushing system, a water distribution device, suspended biological packing, an anoxic tank packing interception device, and an outlet trough.

[0016] Furthermore, the flushing system of the anoxic tank has the same structure as the aeration system of the aerobic tank, and is used to provide an air source during flushing and maintenance.

[0017] Furthermore, the high-efficiency sedimentation tank is internally divided into a mixing reaction zone, a flocculation reaction zone, and an inclined tube sedimentation zone. An effluent trough is located at the top of the inclined tube sedimentation zone, and the surface loading rate of the sedimentation zone is ≤9 m³ / (m².h). A high-speed agitator is installed in the mixing reaction zone, and a slow-speed agitator is installed in the flocculation reaction zone.

[0018] The present invention also provides a wastewater treatment method using the above-mentioned wastewater treatment device, comprising the following steps: anaerobic, sedimentation, aerobic, anoxic and high-efficiency sedimentation.

[0019] Anaerobic process: Wastewater is mixed with sludge rich in polyphosphate-accumulating bacteria returned from the sedimentation tank in an anaerobic tank. Under anaerobic conditions (DO < 0.2 mg / L), polyphosphate-accumulating bacteria decompose the polyphosphates stored within them, releasing phosphates into the water. Simultaneously, they absorb easily degradable organic matter such as volatile fatty acids (VFAs) from the water, synthesizing and storing them as an internal carbon source, polyhydroxyalkanoates (PHAs). This process reserves carbon and energy for subsequent aerobic phosphorus uptake and anoxic denitrification.

[0020] Sedimentation process: The effluent from the anaerobic tank enters the primary sedimentation tank for sludge-water separation. The supernatant enters the subsequent biological treatment unit. 50%-100% of the settled sludge is pumped back to the anaerobic tank inlet via a return pump to ensure sufficient polyphosphate-accumulating bacteria in the anaerobic tank, providing the necessary conditions for the synthesis of internal carbon sources (PHA) and subsequent denitrification in the anoxic tank; excess sludge is periodically discharged to control system sludge age. Simultaneously, the settled wastewater enters the aerobic tank, reducing the impact of suspended solids on the aerobic tank and lowering the frequency of flushing.

[0021] Aerobic process: The supernatant from the sedimentation tank enters the aerobic tank. A blower supplies oxygen through the bottom aeration system, creating a dissolved oxygen gradient within the tank by controlling the aeration rate. The lower part is a high-oxygen zone, and the upper part is a low-oxygen zone. Wastewater flows through a suspended packing layer with a high packing ratio (75-85%). The packing is in a fixed-bed state. In the lower high-oxygen zone, strong aeration decomposes and transforms organic pollutants and ammonia nitrogen. Organic matter is ultimately decomposed into inorganic substances such as carbon dioxide and water, while ammonia nitrogen is oxidized to nitrate. The upper low-oxygen zone allows for short-cut denitrification, further reducing the burden of subsequent anoxic conditions and improving total nitrogen removal efficiency.

[0022] Anoxic process: effluent from the aerobic tank enters the anoxic tank. The internal carbon source (PHA) stored in polyphosphate-accumulating bacteria in the anaerobic tank serves as a carbon source here, utilized by denitrifying bacteria to reduce nitrates produced in the aerobic tank into nitrogen gas, which is released into the atmosphere, thus achieving biological denitrification. This process requires no external carbon source, saving operating costs.

[0023] High-efficiency sedimentation process: effluent from the anoxic tank enters the high-efficiency sedimentation tank to remove residual suspended solids, colloidal substances, and some organic matter. Chemical phosphorus removal is achieved through the addition of auxiliary chemical agents, bringing the effluent quality to near-Class IV water quality standards.

[0024] Regular flushing and maintenance: After 3-5 days of continuous system operation, the flushing program is automatically initiated. During flushing, the system receives water normally, and the water level in the tank is raised by controlling the outlet valve; the hydraulic system is activated to raise the horizontal intercepting screen by 1.0-1.5 meters; simultaneously, the aeration intensity of the aerobic tank is significantly increased, and the flushing aeration pipe at the bottom of the anoxic tank is opened. Under the synergistic effect of air and water, the packing material is fully fluidized, and a strong velocity gradient and vortex are formed from top to bottom in the fluidization space, reconstructing a dynamic, high-intensity shear force field in the vertical direction. This shear force field can efficiently peel off aging biofilm while causing less damage to young biofilm, achieving "selective peeling," thereby quickly restoring biological activity while removing blockages. The flushing process lasts 1-1.5 hours, after which the system automatically returns to normal operation. This process requires no shutdown, no additional flushing water pumps or wastewater tanks, and can achieve continuous 24-hour operation.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. To achieve stable operation at high filling ratios, this invention innovatively integrates a hydraulically adjustable interception device with a gas-water synergistic fluidized bed flushing scheme, enabling controllable and rapid switching between high-density fixed-bed operation and fully fluidized bed cleaning states. This interception device not only prevents packing material loss during normal operation, but its adjustable characteristics are key to achieving efficient and low-consumption flushing. This is fundamentally different from traditional fixed interception nets, high-intensity hydraulic backwashing, or simple gas washing methods, fundamentally solving the core technical problem of easy clogging in high-fill-ratio biofilm reactors. It achieves efficient online maintenance without shutdown or external backwashing systems, ensuring long-term continuous and stable operation of the system.

[0027] 2. By innovatively connecting "anaerobic phosphorus release coupled with sludge recirculation" with "high-filling-ratio (75-85%) biofilm aerobic / anoxic" systems, the traditional internal nitrification liquor recirculation system is completely eliminated. The internal carbon source (PHA) enriched by sludge recirculation drives anoxic denitrification, eliminating the need for internal recirculation equipment and energy consumption, while also avoiding the addition of external carbon sources, significantly reducing operating costs and sludge production. Furthermore, replacing the mechanical mixer with a water distribution device in the anoxic tank further simplifies equipment configuration and energy consumption.

[0028] 3. By using suspended packing material with a high filling ratio of 75%–85%, the biomass concentration in the reactor can reach 3–5 times that of conventional activated sludge processes. The hydraulic retention time (HRT) of the aerobic and anoxic tanks can be shortened by about 40%, resulting in a significant reduction in tank volume. The high-density packing layer has a good retention effect on suspended solids (SS), allowing the elimination of the secondary sedimentation tank after the biological treatment tank, further saving land area and civil engineering investment.

[0029] 4. The dissolved oxygen gradient formed in the aerobic tank promotes simultaneous nitrification and denitrification (SND), saving approximately 20% of aeration. Combining pre-anaerobic phosphorus release, aerobic phosphorus uptake, and post-anaerobic denitrification, and with chemically assisted phosphorus removal through a high-efficiency sedimentation tank, the system possesses strong nitrogen and phosphorus removal capabilities, and the effluent quality can stably meet the near-Class IV standard.

[0030] 5. The flushing process utilizes the system's own water intake and increased aeration intensity to achieve fluidization of the packing material, eliminating the need for auxiliary facilities such as backwash pumps and wastewater tanks, thus reducing initial investment and long-term energy consumption. The entire flushing process can operate automatically in cycles, with a short duration and without affecting normal water intake, achieving true 24-hour continuous flow operation. It is easy to manage and has low operating costs. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a high-density continuous flow biofilm wastewater treatment device provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the aerobic / anoxic tank during normal operation in an embodiment of the present invention. Figure 3 This is a schematic diagram of the flushing state of the aerobic / anoxic tank in an embodiment of the present invention.

[0032] Attached label: 1-Inlet pipe, 2-Anaerobic tank, 3-Submersible mixer, 4-Sedimentation tank, 5-Sludge scraper, 6-Sludge pump, 7-Sludge return pipe, 8-Sludge return electric valve, 9-Residual sludge pipe, 10-Residual sludge electric valve, 11-Aerobic tank, 12-Water distribution channel, 13-Water distribution pipe, 14-Main aeration pipe, 15-Perforated aeration pipe, 16-Catalyst, 17-Aerobic tank packing interception device, 18-Aerobic tank effluent electric valve, 1 9-Aerobic tank flushing water electric valve, 20-Anoxic tank, 21-Anoxic tank flushing device, 22-Anoxic tank water distribution device, 23-Anoxic tank outlet electric valve, 24-Anoxic tank flushing water electric valve, 25-Anoxic tank packing interception device, 26-High-efficiency sedimentation tank, 27-Mixing mixer, 28-Flocculation mixer, 29-Inclined tube, 30-Outlet pipe, 32-Fan, 33-Horizontal interception screen, 34-Lifting frame, 35-Hydraulic system. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] Please see Figures 1 to 3 This invention provides a high-density continuous flow biofilm wastewater treatment device and its treatment method.

[0035] Device Structure

[0036] like Figure 1 As shown, the main treatment facilities of this device include, in sequence along the water flow direction: anaerobic tank 2, sedimentation tank 4, aerobic tank 11, anoxic tank 20 and high-efficiency sedimentation tank 26.

[0037] Wastewater first enters anaerobic tank 2 through inlet pipe 1. A submersible mixer 3 is installed in anaerobic tank 2 to ensure thorough mixing of the influent and returned sludge, maintain the sludge in suspension, and create a homogeneous anaerobic environment. The hydraulic retention time of anaerobic tank 2 is designed to be 2–3 hours.

[0038] The effluent from anaerobic tank 2 enters sedimentation tank 4. In this embodiment, sedimentation tank 4 is a rectangular horizontal flow sedimentation tank with a surface hydraulic load ≤1.3 m³ / (m².h). A chain scraper 5 is installed inside the tank to scrape the settled sludge to the sludge hopper at the bottom of the tank. The sludge in the sludge hopper is returned and discharged by sludge pump 6. A portion of the sludge is returned to the front end of anaerobic tank 2 through sludge return pipe 7 and sludge return electric valve 8, with the return ratio controlled at 50% to 100%. The remaining sludge is discharged from the system through remaining sludge pipe 9 and remaining sludge electric valve 10.

[0039] The supernatant from sedimentation tank 4 flows by gravity into the distribution channel 12 of aerobic tank 11. For example... Figure 2 As shown, the aerobic tank 11 is equipped with an aeration system, a water distribution device, suspended biological filler 16, a filler interception device 17, and an outlet trough, arranged sequentially from bottom to top. The water distribution device includes a distribution channel 12 and perforated water distribution pipes 13. The aeration system consists of a blower 32, a main aeration pipe 14, and several perforated aeration pipes 15 evenly distributed at the bottom of the tank. The perforated aeration pipes 15 have an aperture of 2-4 mm to ensure fine and dispersed air bubbles and high oxygen transfer efficiency (≥27%). The water distribution device is located above the aeration system and consists of the distribution channel 12 and the perforated water distribution pipes 13. The perforated water distribution pipes have an aperture of 15-20 mm, are evenly distributed in a quincunx pattern, and the flow velocity through the perforations is controlled at 0.1-0.3 m / s to ensure uniform water intake. The suspended biological filler 16 is a porous filler with a specific surface area ≥650 m² / m³, filled with a high filling ratio of 75%-85%. The aerobic tank packing interception device 17 is located above the packing layer and consists of a horizontal interception screen 33, a lifting frame 34, and a hydraulic system 35. The horizontal interception screen 33 has an opening diameter of 15-20 mm and a flow velocity of 0.05-0.1 m / s during normal operation, which is used to prevent the packing 16 from being lost.

[0040] The effluent from the aerobic tank 11 enters the anoxic tank 20 through the aerobic tank effluent electric valve 18. The structure of the anoxic tank 20 is similar to that of the aerobic tank 11, and its interior also includes, from bottom to top, an anoxic tank flushing device 21, an anoxic tank water distribution device 22, suspended biological packing material 16, and an anoxic tank packing material interception device 25. The structure of the anoxic tank flushing device 21 is the same as that of the aeration system in the aerobic tank, which also includes a main aeration pipe 14 and several perforated aeration pipes 15 evenly distributed at the bottom of the tank. It is closed during normal operation and only turned on for flushing and maintenance. The anoxic tank water distribution device 22 is also used for uniform water distribution, replacing traditional mechanical stirring.

[0041] The effluent from the anoxic tank 20 enters the high-efficiency sedimentation tank 26 via the anoxic tank effluent electric valve 23. The high-efficiency sedimentation tank 26 is internally divided into a mixing reaction zone, a flocculation reaction zone, and an inclined tube sedimentation zone. The mixing reaction zone is equipped with a high-speed mixer 27, and the flocculation reaction zone is equipped with a low-speed flocculation mixer 28. Inclined tubes 29 are installed in the inclined tube sedimentation zone to improve sedimentation efficiency, with a surface loading rate ≤9 m³ / (m².h). The treated clear water is finally discharged through the effluent pipe 30, meeting all discharge standards.

[0042] The wastewater treatment method using the above-mentioned equipment is as follows:

[0043] Anaerobic digestion and internal carbon source synthesis: Raw wastewater enters anaerobic tank 2 through inlet pipe 1, where it is thoroughly mixed with sludge rich in polyphosphate-accumulating organisms (PAOs) returned from sedimentation tank 4 via sludge return pipe 7. Under the action of submersible mixer 3, an anaerobic environment with DO < 0.2 mg / L is maintained within the tank. In this environment, PAOs decompose their stored polyphosphates and release phosphates, while simultaneously absorbing small-molecule organic matter such as volatile fatty acids (VFAs) from the wastewater and converting them into an internal carbon source—polyhydroxyalkanoates (PHAs).

[0044] Sedimentation and sludge return: The mixed liquor from anaerobic tank 2 enters sedimentation tank 4 for solid-liquid separation. The supernatant enters aerobic tank 11, while the settled sludge is pumped back to anaerobic tank 2 via sludge pump 6 at a high return ratio of 50%–100%. This significantly increases the sludge concentration and polyphosphate-accumulating bacteria abundance in anaerobic tank 2, enhances PHA synthesis, and provides a sufficient high-quality internal carbon source for subsequent anoxic denitrification. Simultaneously, the primary sedimentation step reduces the suspended solids load entering the subsequent biofilm system.

[0045] Aerobic nitrification and phosphorus uptake: The supernatant from sedimentation tank 4 enters aerobic tank 11, where oxygen is supplied through the bottom aeration system to maintain DO at 2.0-4.0 mg / L. Wastewater flows evenly upwards through a high-fill-ratio suspended biological packing material bed 16 via the distribution device (distribution channel 12) and perforated distribution pipe 13. The aerobic biofilm on the packing material surface oxidizes and decomposes organic matter such as COD and BOD in the water, while simultaneously oxidizing ammonia nitrogen (NH4⁺-N) to nitrate (NO3⁻-N). During this process, polyphosphate-accumulating bacteria utilize previously stored PHA as energy to excessively absorb phosphate from the water, achieving biological phosphorus removal.

[0046] Anoxic denitrification: The effluent (rich in nitrates) from aerobic tank 11 enters anoxic tank 20. The dissolved oxygen (DO) in the tank is controlled within the anoxic range of 0.2-0.5 mg / L. Denitrifying bacteria (some of which are denitrifying polyphosphate-accumulating bacteria, DPAOs) attached to the suspended biological packing material 16 utilize the PHA stored in the microorganisms from the previous step as electron donors to reduce nitrates to nitrogen gas (N2), which escapes from the water, completing the denitrification process. Because an internal carbon source is used, there is no need to add external carbon sources such as methanol, reducing costs.

[0047] High-efficiency sedimentation and advanced treatment: The effluent from the anoxic tank 20 enters the high-efficiency sedimentation tank 26, where flocculants and coagulants can be added as needed. After reacting in the mixing mixer 27 and the flocculation mixer 28, residual suspended solids are efficiently removed in the sedimentation zone of the inclined tube 29. If higher requirements are required for the total phosphorus in the effluent, iron salts or aluminum salts can be added at this step for chemically assisted phosphorus removal to ensure that the final effluent meets the near-Class IV water standard.

[0048] Regular flushing and maintenance

[0049] like Figure 2 and Figure 3 As shown, one of the core advantages of this invention lies in its unique online flushing and maintenance mechanism. After the system has been running continuously for 3 to 5 days, the control system will automatically start the flushing program. During normal operation, the water level in the tanks is kept at the operating level by adjusting the opening of the aerobic tank outlet electric valve 18 and the anoxic tank outlet electric valve 23. When flushing is required, the opening of the aerobic tank flushing water electric valve 19 and the anoxic tank flushing water electric valve 24 is adjusted to raise the water level in the tanks to the flushing level. Subsequently, the hydraulic system 35 is activated, driving the lifting frame 34 to lift the horizontal intercepting screen 33 upwards by 1.0 to 1.5 meters, providing sufficient vertical space for the fluidization of the suspended biological packing material 16 (e.g., Figure 3 (As shown). Next, blower 32 increases the air supply to aerobic tank 11, forming strong aeration; simultaneously, the anoxic tank flushing device 21 is activated for aeration. The powerful airflow, synergistic with the forward water flow, causes the high-fill-ratio packing material 16 bed to violently churn, collide, and rub against each other, reaching a fully fluidized state. This efficiently removes excess aged biofilm and trapped suspended solids from the packing surface. After the flushing process lasts approximately 1-1.5 hours, the aeration rate returns to normal, the anoxic tank flushing device 21 is shut off, and the hydraulic system 35 slowly lowers the aerobic tank packing interception device 17 and the anoxic tank packing interception device 25 back to their original positions. The system seamlessly switches back to normal operating mode (e.g., ...). Figure 2 (As shown). The entire rinsing process is completed online without shutdown, and there is no need for backwash water pumps or wastewater tanks, achieving true continuous flow operation and greatly improving the stability and economy of equipment operation.

[0050] In summary, this invention, through its unique process design and innovative device structure, particularly the combination of a liftable packing interceptor and air-water synergistic flushing technology, successfully solves the clogging problem of high-density biofilm reactors in continuous flow applications. It achieves miniaturization, high efficiency, and low-consumption operation of the device, providing a highly competitive technical option for the construction of underground wastewater treatment plants.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-density continuous flow biofilm wastewater treatment device, characterized in that, The system includes an anaerobic tank (2), a sedimentation tank (4), an aerobic tank (11), an anoxic tank (20), and a high-efficiency sedimentation tank (26) connected in sequence. Suspended biological packing material (16) is installed in the aerobic tank (11) and the anoxic tank (20), and corresponding aerobic tank packing interception device (17) and anoxic tank packing interception device (25) are installed above the suspended biological packing material (16). The aerobic tank packing interception device (17) and the anoxic tank packing interception device (25) are both vertically lifting structures, which are used to be lifted in the flushing state to expand the activity space of the suspended biological packing material (16) and realize the controllable switching of the operating state from fixed bed to fluidized bed.

2. The apparatus according to claim 1, characterized in that, Both the aerobic pool packing interception device (17) and the anoxic pool packing interception device (25) include a horizontal interception screen (33), a lifting frame (34) for supporting the horizontal interception screen (33), and a hydraulic system (35) for driving the lifting frame (34) to rise and fall vertically.

3. The apparatus according to claim 1 or 2, characterized in that, In the aerobic tank (11) and the anoxic tank (20), the filling ratio of the suspended biological packing material (16) is 75% to 85%.

4. The apparatus according to claim 1, characterized in that, The aerobic tank (11) is provided with an aeration system consisting of an aeration main pipe (14) and a perforated aeration pipe (15), a water distribution device, the suspended biological packing material (16), and the aerobic tank packing material interception device (17) arranged sequentially from bottom to top. The water distribution device includes a water distribution channel (12) and a perforated water distribution pipe (13).

5. The apparatus according to claim 1, characterized in that, The anoxic pool (20) is provided with anoxic pool flushing device (21), anoxic pool water distribution device (22), suspended biological packing material (16) and anoxic pool packing material interception device (25) in sequence from bottom to top; the structure of the anoxic pool flushing device (21) is the same as the aeration system structure of the aerobic pool (11).

6. The apparatus according to claim 1, characterized in that, It also includes a sludge return system, which includes a sludge return pipe (7) that returns the sludge from the bottom of the sedimentation tank (4) to the front end of the anaerobic tank (2) and a sludge pump (6).

7. A wastewater treatment method using the apparatus according to any one of claims 1 to 6, characterized in that, Includes the following steps: a) Anaerobic step: Wastewater enters the anaerobic tank (2) and mixes with sludge returned from the sedimentation tank (4) for anaerobic phosphorus release and internal carbon source synthesis; b) Sedimentation step: The effluent from the anaerobic tank (2) enters the sedimentation tank (4) for sludge-water separation, the supernatant enters step c), part of the settled sludge is returned to step a), and the remaining sludge is discharged; c) Aerobic step: The supernatant from the sedimentation tank (4) enters the aerobic tank (11) for organic matter degradation and ammonia nitrogen nitrification under aerobic conditions; d) Anoxic step: The effluent from the aerobic tank (11) enters the anoxic tank (20) for denitrification using the internal carbon source synthesized in step a); e) High-efficiency sedimentation step: The effluent from the anoxic tank (20) enters the high-efficiency sedimentation tank (26) for deep treatment before being discharged.

8. The method according to claim 7, characterized in that, It also includes a regular flushing and maintenance procedure: after the system has been running continuously, water is introduced normally and the water levels in the aerobic tank (11) and the anoxic tank (20) are raised; the hydraulic system (35) is started to raise the aerobic tank packing interceptor (17) and the anoxic tank packing interceptor (25) to a predetermined height; the aeration intensity of the aerobic tank (11) is increased and the anoxic tank flushing device (21) is turned on for aeration, so that the suspended biological packing (16) is fluidized under the synergistic effect of air and water to remove the aging biofilm; after flushing, the aerobic tank packing interceptor (17) and the anoxic tank packing interceptor (25) are reset and the system returns to normal operation.

9. The method according to claim 8, characterized in that, During the flushing and maintenance step, the height to which the aerobic tank packing interception device (17) and the anoxic tank packing interception device (25) are raised is 1.0 to 1.5 meters.

10. The method according to claim 7, characterized in that, In the sedimentation step b), the sludge is returned to the anaerobic tank (2) at a rate of 50% to 100%.

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