A small, high-efficiency, energy-saving and land-saving biological denitrification and dephosphorization treatment device

Abstract

This invention relates to the field of wastewater treatment equipment technology, and discloses a small, efficient, energy-saving, and land-saving biological nitrogen and phosphorus removal treatment device, including an anaerobic / anoxic unit, an aerobic unit, a submersible pump, a Venturi tube, a gas-liquid mixing pipe, and a nitrate return pipe. The anaerobic / anoxic unit and the aerobic unit are directly connected to form an integrated structure. The submersible pump is fixedly installed at the bottom inside the anaerobic / anoxic unit. The outlet end of the submersible pump is sealed to the inlet end of the Venturi tube through a wastewater lift pipe. The air inlet end of the Venturi tube is connected to an air pipe. The outlet end of the Venturi tube is sealed to one end of the gas-liquid mixing pipe. The other end of the gas-liquid mixing pipe extends into the aerobic unit. The two ends of the nitrate return pipe are respectively connected to the aerobic unit and the anaerobic / anoxic unit. This invention can stably achieve biological nitrogen and phosphorus removal functions, while eliminating the need for a separate sedimentation unit and a dedicated sludge tank, simplifying the structure and improving operational stability and ease of operation.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment equipment technology. Background Technology

[0002] With increasingly stringent environmental protection requirements, high-efficiency, miniaturized, and energy-saving wastewater treatment equipment is needed for production and living scenarios with low wastewater production and high discharge standards, such as highway toll stations, service areas with low pedestrian traffic, gas stations, campsites, rural areas, scenic spots, docks, and passenger transport stations. Traditional biological wastewater treatment equipment has many problems. For example, conventional small-scale wastewater treatment devices require separate spaces for anaerobic, anoxic, and aerobic processes in the physicochemical and biochemical treatment processes, resulting in large equipment footprints, low space utilization efficiency, and high construction costs. Furthermore, existing aeration technologies mostly rely on blowers, which have high energy consumption and operating costs for situations with small and dispersed wastewater production. Specifically, the following problems exist: 1. Currently, most small-scale energy-saving biological treatment devices for domestic sewage on the market are still based on traditional processes, such as the simple application of activated sludge + sedimentation and biofilm + sedimentation, lacking innovative breakthroughs.

[0003] 2. Many existing small devices have not achieved a high degree of integration. Each processing unit is independent, occupies a large area, has poor coordination between devices, and has a relatively high purchase price.

[0004] 3. The operating costs of small-scale biological wastewater treatment devices on the market are still relatively high, mainly due to electricity costs for aeration blowers, digestion return pumps, mixers, etc. Summary of the Invention

[0005] The purpose of this invention is to provide a small, efficient, energy-saving, and land-saving biological nitrogen and phosphorus removal treatment device, which has the advantages of energy saving, land saving, simple structure, stable operation, and convenient maintenance. The effluent meets the standards and is suitable for a variety of small-scale sewage treatment scenarios.

[0006] To address the aforementioned technical problems, this invention provides a small, efficient, energy-saving, and land-saving biological nitrogen and phosphorus removal treatment device, comprising an anaerobic / anoxic unit, an aerobic unit, a submersible pump, a Venturi tube, a gas-liquid mixing pipe, and a nitrate return pipe. The anaerobic / anoxic unit and the aerobic unit are directly connected to form an integrated structure. The submersible pump is fixedly installed at the bottom inside the anaerobic / anoxic unit. The outlet end of the submersible pump is sealed to the inlet end of the Venturi tube through a sewage lift pipe. The air inlet end of the Venturi tube is connected to an air pipe. The outlet end of the Venturi tube is sealed to one end of the gas-liquid mixing pipe. The other end of the gas-liquid mixing pipe extends into the aerobic unit. The two ends of the nitrate return pipe are respectively connected to the aerobic unit and the anaerobic / anoxic unit.

[0007] The anaerobic / anoxic unit is equipped with baffles fixedly installed inside. The baffles are arranged at intervals along the length of the anaerobic / anoxic unit, dividing the anaerobic / anoxic unit into multiple independent compartments connected in series. The water flow forms an up-and-down flow path along the baffles, so that the front compartment of the anaerobic / anoxic unit forms an anaerobic environment and the rear compartment forms an anoxic environment.

[0008] ABR packing is fixedly installed in each series compartment inside the anaerobic / anoxic unit, and the ABR packing is evenly distributed in the central area of ​​each compartment.

[0009] Inside the anaerobic / anoxic unit, a water-passing net is fixedly installed at the corresponding location of the submersible sewage pump, and the water-passing net is arranged around the submersible sewage pump.

[0010] An inlet pipe is fixedly installed on the front side wall of the anaerobic / anoxic unit. One end of the inlet pipe passes through the side wall of the anaerobic / anoxic unit and extends into the front compartment, while the other end is used to connect to an external source of wastewater to be treated.

[0011] A water outlet pipe is fixedly installed on the rear side wall of the aerobic unit, with one end of the water outlet pipe penetrating through the side wall of the aerobic unit and extending into its interior.

[0012] A sludge discharge pipe is fixedly installed at the bottom of the anaerobic / anoxic unit. One end of the sludge discharge pipe passes through the bottom of the anaerobic / anoxic unit and communicates with the interior. A sludge discharge valve is fixedly installed on the sludge discharge pipe, and the other end of the sludge discharge pipe is connected to the septic tank.

[0013] The number of submersible sewage pumps is two, with one pump in use and one on standby, both fixedly installed at the bottom inside the anaerobic / anoxic unit.

[0014] One end of the nitrate reflux pipe is connected to the upper region of the aerobic unit, and the other end is connected to the rear region of the anaerobic / anoxic unit.

[0015] The baffle plate is a vertical baffle plate, and the baffle plate is arranged at a preset angle.

[0016] Compared to existing technologies, this invention significantly reduces the footprint of the device by integrating anaerobic / anoxic and aerobic units, optimizing the layout of baffles and ABR packing, and providing protection through the water flow network, thus achieving land-saving effects. The aeration and recirculation structure using submersible pumps and venturi tubes eliminates the need for traditional equipment such as oxygen supply fans, aeration heads, anoxic mixers, and mixed liquor recirculation pumps, requiring only two submersible pumps (one for operation and one for standby), effectively reducing energy consumption and operating and maintenance costs, achieving energy-saving goals. Furthermore, the directional layout of the nitrate recirculation pipe and the combination of the sludge discharge pipe and sludge discharge valve further enhance the energy efficiency. The rational configuration and coordinated operation of each component ensure that the device can stably achieve biological nitrogen and phosphorus removal. Except for suspended solids and E. coli, other effluent indicators meet the Class A standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002). At the same time, there is no need to set up a separate sedimentation unit and a dedicated sludge tank, which simplifies the device structure, improves operational stability and ease of operation, and is suitable for small and decentralized wastewater treatment scenarios such as highway toll stations, service areas, and rural areas. It effectively overcomes the problems of large footprint, high energy consumption, unstable operation, and difficult maintenance of traditional small wastewater treatment devices.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0019] Figure 1 This is a schematic diagram of the structure of at least one embodiment of the present invention; Figure 2 yes Figure 1 A schematic diagram of the process principle.

[0020] In the diagram: 1-Inlet pipe, 2-Internal baffle, 3-ABR packing, 4-Water filter, 5-Nitrogen return pipe, 6-Sewage lift pipe, 7-Air pipe, 8-Venturi pipe, 9-Gas-liquid mixing pipe, 10-Outlet pipe, 11-Submersible sewage pump, 12-Anaerobic / Anoxic unit, 13-Aerobic unit, 14-Sludge discharge pipe, 15-Sludge discharge valve. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the embodiments of this invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this invention. The embodiments can be combined with and referenced by each other without contradiction.

[0022] Example 1 like Figure 1 , Figure 2 The small, efficient, energy-saving, and land-saving biological nitrogen and phosphorus removal device shown includes an anaerobic / anoxic unit 12, an aerobic unit 13, a submersible pump 11, a venturi tube 8, a gas-liquid mixing pipe 9, and a nitrate return pipe 5. These components work together to achieve biological nitrogen and phosphorus removal. The anaerobic / anoxic unit 12 and the aerobic unit 13 are integrally cast and directly connected to form a complete integrated structure, eliminating the need for additional connecting pipelines and significantly reducing the overall volume of the device. Submersible sewage pump 11 is bolted to the bottom of the anaerobic / anoxic unit 12. The outlet of pump 11 is sealed to one end of sewage lift pipe 6 via a flange. The other end of sewage lift pipe 6 is sealed to the inlet of venturi pipe 8. The air inlet of venturi pipe 8 is connected to air pipe 7 via an interface, allowing air to be introduced into venturi pipe 8. The outlet of venturi pipe 8 is fixed to one end of gas-liquid mixing pipe 9 via a clamp. The other end of gas-liquid mixing pipe 9 extends to the middle of the aerobic unit 13, ensuring that the gas-liquid mixture can be evenly diffused throughout the aerobic unit 13. Nitrate return pipe 5 connects to both ends of aerobic unit 13 and anaerobic / anoxic unit 12, forming a nitrate circulation channel, enabling the return of nitrate from aerobic unit 13 to anaerobic / anoxic unit 12.

[0023] By integrating the anaerobic / anoxic unit 12 with the aerobic unit 13, the traditional process of setting up each treatment unit independently and requiring additional pipeline connections is eliminated, thus achieving a land-saving effect in terms of structure. At the same time, the structure of using a submersible pump 11 in conjunction with a venturi tube 8 replaces the oxygen supply fan, aeration head and other equipment in the traditional process, effectively overcoming the problems of large footprint, high energy consumption and complex assembly of traditional small sewage treatment devices, and achieving the technical advantages of energy saving, land saving and simple structure.

[0024] Example 2 Based on Example 1, baffles 2 are fixedly installed inside the anaerobic / anoxic unit 12. The baffles 2 have a vertical structure and are evenly spaced along the length of the anaerobic / anoxic unit 12. The spacing between adjacent baffles 2 is reasonably set according to the overall size of the anaerobic / anoxic unit 12. The baffles 2 divide the anaerobic / anoxic unit 12 into multiple independent compartments connected in series, allowing the water flow to form an upward and downward flow path along the baffles 2, ensuring sufficient residence time for wastewater within the anaerobic / anoxic unit 12. In each compartment connected in series inside the anaerobic / anoxic unit 12, ABR packing 3 is fixedly installed. The ABR packing 3 has a honeycomb structure and is evenly filled inside each compartment. Its installation height is adapted to the effective water depth of the compartment, ensuring that the wastewater can fully contact the ABR packing 3. Inside the anaerobic / anoxic unit 12, a water-passing mesh 4 is fixedly installed at the location corresponding to the submersible sewage pump 11. The water-passing mesh 4 is made of stainless steel and surrounds the submersible sewage pump 11. Its aperture is adapted to the sludge interception requirements and is fixedly connected to the mounting base of the submersible sewage pump 11. At the same time, the baffle plate 2 is a vertical baffle plate. The baffle plate 2 is inclined at a preset angle, with the inclination angle controlled between 30° and 60°, to adapt to the water flow direction and ensure smooth water flow without creating stagnant water zones.

[0025] Therefore, the spaced arrangement of the baffles 2, combined with the upper and lower baffle paths, solves the problems of short-circuiting water flow and insufficient residence time in traditional anaerobic / anoxic units; the arrangement of the ABR packing 3 can enrich anaerobic microorganisms and improve wastewater treatment efficiency; the water flow net 4 is set around the submersible pump 11, which can effectively intercept sludge, prevent the submersible pump 11 from being blocked or worn by sludge during operation, and extend the service life of the equipment; the inclined vertical baffles 2 further optimize the water flow path and improve the water mass transfer efficiency. Through the above structural optimization, the problems of low mass transfer efficiency, easy sludge loss, and easy equipment damage in traditional anaerobic / anoxic units are overcome. Combined with the basic structure of Example 1, the efficiency and stability are further enhanced.

[0026] Example 3 Based on Embodiment 1, an inlet pipe 1 is fixedly installed on the front side wall of the anaerobic / anoxic unit 12. The inlet pipe 1 is made of PVC, with one end penetrating the side wall of the anaerobic / anoxic unit 12 and extending into the front compartment of the anaerobic / anoxic unit 12, with an extension length of not less than 10cm. The other end of the inlet pipe 1 is used to connect to an external source of wastewater to be treated, ensuring that wastewater can be directly introduced into the front anaerobic area of ​​the anaerobic / anoxic unit 12. An outlet pipe 10 is fixedly installed on the rear side wall of the aerobic unit 13. The outlet pipe 10 is made of the same material as the inlet pipe 1, with one end penetrating the side wall of the aerobic unit 13 and extending into the interior of the aerobic unit 13. The extended end is close to the bottom of the aerobic unit 13, ensuring that the treated water can be completely discharged. A sludge discharge pipe 14 is fixedly installed at the bottom of the anaerobic / anoxic unit 12. One end of the sludge discharge pipe 14 passes through the bottom of the anaerobic / anoxic unit 12 and communicates with the interior. The other end of the sludge discharge pipe 14 is used to connect to the septic tank. A sludge discharge valve 15 is fixedly installed on the sludge discharge pipe 14. The sludge discharge valve 15 adopts a ball valve structure and is used to control the start and stop of the sludge discharge process. There are two submersible sewage pumps 11, which are configured in a redundant manner with one in use and one on standby. Both are fixed to the bottom of the anaerobic / anoxic unit 12 with bolts. The installation distance between the two submersible sewage pumps 11 is not less than 50cm to ensure that they do not interfere with each other during operation. One end of the nitrate return pipe 5 is connected to the upper area of ​​the aerobic unit 13, and the connection position is close to the top of the aerobic unit 13. The other end is connected to the rear area of ​​the anaerobic / anoxic unit 12, and the connection position corresponds to the rear compartment of the anaerobic / anoxic unit 12, ensuring that the nitrate can be accurately returned to the anoxic area.

[0027] Therefore, the placement of the inlet pipe 1 and outlet pipe 10 ensures that sewage can enter and exit the device in an orderly manner, avoiding problems such as uneven water intake and incomplete water discharge. The cooperation between the sludge discharge pipe 14 and the sludge discharge valve 15 enables the orderly discharge of excess sludge, eliminating the need for a separate sludge tank and further demonstrating land-saving advantages. Two submersible sewage pumps 11, one in operation and one on standby, ensure continuous operation and prevent system shutdown due to the failure of a single unit. The directional placement of the nitrification return pipe 5 ensures precise nitrification return, guaranteeing the smooth progress of the denitrification reaction. Based on the above, the problems of poor water intake and discharge, inconvenient sludge discharge, poor operational stability, and inaccurate nitrification return of traditional small sewage treatment devices are overcome, achieving efficient and stable operation.

[0028] Example 4 Based on the above embodiments, including the improved ABR anaerobic / anoxic + aerobic integrated biological carbon and nitrogen removal treatment device, without the front-end bar equalization tank system and the back-end filtration and disinfection advanced treatment system, this part of the process section can be constructed according to relevant specifications.

[0029] (1) Anaerobic / Anoxic Zones (Core Functions: Phosphorus Release, Denitrification, Hydrolysis and Acidification) The ABR is divided into multiple compartments by baffles, and the water flow is driven up and down by the baffles, naturally forming an anaerobic environment at the front end and an anoxic environment at the back end: Anaerobic end: In anaerobic phosphorus release wastewater, easily degradable CODcr is absorbed by polyphosphate-accumulating bacteria; polyphosphate-accumulating bacteria decompose the polyphosphates stored in their bodies, releasing orthophosphate into the water, which serves as a reserve for subsequent aerobic excessive phosphorus uptake; at the same time, they hydrolyze and acidify large molecular organic matter, degrading some small molecular organic matter.

[0030] Anoxic end: Nitrate nitrogen returned from the denitrification and aerobic tank enters the anoxic zone of the ABR; using the organic carbon source of the raw wastewater as an electron donor, denitrifying bacteria reduce nitrate nitrogen to nitrogen gas and release it, thus completing the denitrification process; (2) Aerobic tank section: ① Nitrification reaction: Under the action of nitrifying bacteria, ammonia nitrogen is first oxidized to nitrite nitrogen, and then oxidized to nitrate nitrogen; nitrate nitrogen is returned to the anoxic zone of the ABR through internal reflux for continued denitrification. ② Aerobic polyphosphate-accumulating bacteria utilize the PHA stored in the anaerobic stage as energy to excessively absorb orthophosphate in the water and store it in the form of polyphosphate in their bodies; by discharging excess sludge, phosphorus is permanently removed from the system, achieving biological phosphorus removal. ③ Deep degradation of organic matter: The remaining recalcitrant CODcr is further mineralized under the action of aerobic microorganisms to ensure that the effluent CODcr meets the standards.

[0031] Therefore, the improved ABR reactor of this invention is divided into multiple series-connected compartments by vertical baffles, forming a vertically baffled flow path. The compartmentalized flow pattern is close to plug flow, with no short-circuiting, resulting in high sludge concentration and extended contact time between wastewater and sludge. Therefore, considering the same theoretical contact time for wastewater, the improved ABR reactor requires less volume and occupies less space than conventional reactors. The anaerobic / anoxic environment dominates, with each compartment being facultative anaerobic or anoxic, and the sludge bed enriched with a large number of anaerobic microorganisms (such as acid-producing bacteria and methanogens). By adjusting the baffle angle and adding packing material, the mass transfer efficiency and sludge retention capacity are improved. Excess sludge settles at the bottom of the compartment and is discharged, achieving total phosphorus removal and significantly reducing suspended solids in the effluent. The sedimentation unit at the rear of the reactor can be eliminated. Using the ABR packing method, the system produces less excess sludge, eliminating the need for a separate sludge tank. The sludge can flow by gravity to the septic tank, and is periodically transported off-site. The integrated device has only two submersible sewage pumps (one for use and one for standby). The submersible sewage pumps lift sewage and combine with the venturi tubes to form a gas-liquid mixture to achieve aeration in the aerobic tank and gravity nitrification return. The submersible sewage pumps are configured with a return ratio of 100%. The selected pumps have lower parameters than the nitrification return pumps of traditional processes (return ratio ≥200%). At the same time, it reduces the need for equipment such as mixers, oxygen supply fans, and aeration heads compared to traditional processes, resulting in lower construction and operating costs.

[0032] Those skilled in the art will understand that the above embodiments can be modified in form and detail in practical applications without departing from the spirit and scope of the invention.

Claims

1. A small, high-efficiency, energy-saving, and land-saving biological denitrification and dephosphorization treatment device, characterized in that, It includes an anaerobic / anoxic unit (12), an aerobic unit (13), a submersible pump (11), a venturi tube (8), a gas-liquid mixing pipe (9), and a nitrate return pipe (5). The anaerobic / anoxic unit (12) and the aerobic unit (13) are directly connected to form an integrated structure. The submersible pump (11) is located at the bottom inside the anaerobic / anoxic unit (12). The outlet end of the submersible pump (11) is sealed to the inlet end of the venturi tube (8) through the sewage lift pipe (6). The air inlet end of the venturi tube (8) is connected to the air pipe (7). The outlet end of the venturi tube (8) is sealed to one end of the gas-liquid mixing pipe (9). The other end of the gas-liquid mixing pipe (9) extends into the aerobic unit (13). The two ends of the nitrate return pipe (5) are respectively connected to the aerobic unit (13) and the anaerobic / anoxic unit (12).

2. The small, high-efficiency, energy-saving, and land-saving biological denitrification and dephosphorization treatment device according to claim 1, characterized in that, The anaerobic / anoxic unit (12) is fixedly equipped with baffles (2). The baffles (2) are arranged at intervals along the length of the anaerobic / anoxic unit (12) to divide the anaerobic / anoxic unit (12) into multiple independent compartments connected in series. The water flow forms an up-and-down baffle propulsion path along the baffles (2), so that the front compartment of the anaerobic / anoxic unit (12) forms an anaerobic environment and the rear compartment forms an anoxic environment.

3. The small, high-efficiency, energy-saving, and land-saving biological nitrogen and phosphorus removal treatment device according to claim 2, characterized in that, ABR packing material (3) is fixedly installed in each series compartment inside the anaerobic / anoxic unit (12), and the ABR packing material (3) is evenly distributed in the middle area of ​​each compartment.

4. The small, high-efficiency, energy-saving, and land-saving biological nitrogen and phosphorus removal treatment device according to claim 2, characterized in that, Inside the anaerobic / anoxic unit (12), a water-passing net (4) is fixedly installed at the location corresponding to the submersible sewage pump (11), and the water-passing net (4) is arranged around the submersible sewage pump (11).

5. The small, high-efficiency, energy-saving, and land-saving biological nitrogen and phosphorus removal treatment device according to claim 1, characterized in that, An inlet pipe (1) is fixedly installed on the front side wall of the anaerobic / anoxic unit (12). One end of the inlet pipe (1) passes through the side wall of the anaerobic / anoxic unit (12) and extends into the front compartment, while the other end is used to connect to an external sewage source to be treated.

6. The small, high-efficiency, energy-saving, and land-saving biological nitrogen and phosphorus removal treatment device according to claim 1, characterized in that, A water outlet pipe (10) is fixedly installed on the rear side wall of the aerobic unit (13), and one end of the water outlet pipe (10) penetrates the side wall of the aerobic unit (13) and extends into its interior.

7. The small, high-efficiency, energy-saving, and land-saving biological nitrogen and phosphorus removal treatment device according to claim 1, characterized in that, A sludge discharge pipe (14) is fixedly installed at the bottom of the anaerobic / anoxic unit (12). One end of the sludge discharge pipe (14) passes through the bottom of the anaerobic / anoxic unit (12) and communicates with the interior. A sludge discharge valve (15) is fixedly installed on the sludge discharge pipe (14), and the other end of the sludge discharge pipe (14) is connected to the septic tank.

8. The small-scale, high-efficiency, energy-saving, and land-saving biological nitrogen and phosphorus removal treatment device according to claim 1, characterized in that, The number of submersible sewage pumps (11) is two, and the two submersible sewage pumps (11) are configured with one in use and one on standby, and are both located at the bottom inside the anaerobic / anoxic unit (12).

9. The small-scale, high-efficiency, energy-saving, and land-saving biological nitrogen and phosphorus removal treatment device according to claim 1, characterized in that, One end of the nitrate reflux pipe (5) is connected to the upper region of the aerobic unit (13), and the other end is connected to the rear region of the anaerobic / anoxic unit (12).

10. The small, high-efficiency, energy-saving, and land-saving biological nitrogen and phosphorus removal treatment device according to claim 2, characterized in that, The baffle plate (2) is a vertical baffle plate, and the baffle plate (2) is arranged at a preset angle.

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