Integrated sewage treatment system

Abstract

The utility model discloses an integrated sewage treatment system relates to sewage treatment technical field, and this system includes the pretreatment unit, biochemical treatment unit, secondary treatment unit and sludge treatment unit that connect gradually, and biochemical treatment unit includes the anaerobic pool, the anoxic MBBR pool and CWSBR biological pool that connect gradually, and CWSBR biological pool includes the aerobic MBBR pool, reaction area and balance area that arrange gradually, and secondary treatment unit is used to carry out flocculation precipitation and filtration treatment to sewage, and sludge treatment unit is used to carry out centralized treatment to the sludge of each unit generation, the utility model discloses through multistage biochemical coupling and depth treatment combination, and the efficiency of denitrification and phosphorus removal and the anti -impact load capacity of a large margin are promoted, and the effluent quality is stable, and the sludge centralized disposal, and the system integration degree is high, and the land area is small, and the operation cost is low, is applicable to town sewage and industrial waste water treatment.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology and discloses an integrated wastewater treatment system. Background Technology

[0002] With the continuous improvement of urban sewage treatment and discharge standards, there are further requirements for industrial sewage treatment and discharge. Urban sewage has complex sources and diverse water quality and quantity, containing a large amount of suspended solids, organic pollutants, nutrients such as nitrogen and phosphorus, as well as bacteria and viruses. To meet the Class IV surface water standard, at least a combination of three treatment processes (physical, biological, and advanced treatment) is required to improve sewage treatment efficiency.

[0003] Existing wastewater treatment processes generally employ the Constant Water Level Sequencing Batch Reactor (CWSBR) process. This process involves setting up a CWSBR wastewater treatment tank with an aeration system. Aeration and aeration cycles are used to achieve aerobic and anoxic reaction processes within the tank, thereby degrading and removing nitrogen. When aeration stops, the sludge settles automatically. Currently, the mainstream process for treating ammonia nitrogen and total nitrogen uses nitrification-denitrification. Because the reduction of organic carbon sources is significant with increasing treatment efficiency, sodium acetate or glucose is typically added to the denitrification stage to increase the organic carbon source and improve the total nitrogen removal rate. Nitrification is performed with aerobic aeration, with dissolved oxygen controlled at approximately 3-5 mg / L, while denitrification is performed in an anoxic tank, with dissolved oxygen controlled at approximately 0.2-0.5 mg / L.

[0004] However, the drawback of this process is that the CWSBR process relies on alternating time-series formation of anoxic and aerobic environments. There is no strict physical separation between the anoxic and aerobic zones, allowing dissolved oxygen from the aerobic zone to easily seep into the anoxic zone, making it difficult to maintain a stable low / anoxic environment. This results in insufficient denitrification and low total nitrogen removal efficiency. Furthermore, the lack of independent anaerobic and anoxic sections leads to insufficient phosphorus release by polyphosphate-accumulating bacteria and insufficient carbon sources for denitrification, creating inherent contradictions in nitrogen and phosphorus removal. Moreover, the system has weak resistance to water quality and quantity fluctuations; large fluctuations in influent suspended solids can easily lead to problems such as floating sludge in the anaerobic tank and overloading of the biological treatment, making it difficult for effluent suspended solids, total nitrogen, and total phosphorus to simultaneously and stably meet standards. Utility Model Content

[0005] In view of the above problems, this utility model is proposed to provide an integrated wastewater treatment system that overcomes or at least partially solves the above problems, and can solve the problems mentioned in the background art.

[0006] To achieve the above-mentioned technical effects, the technical solution adopted by this utility model is: an integrated sewage treatment system, comprising: a pretreatment unit, a biochemical treatment unit, a secondary treatment unit, and a sludge treatment unit connected in sequence; the biochemical treatment unit includes an anaerobic tank, an anoxic MBBR tank, and a CWSBR biological tank connected in sequence; the CWSBR biological tank includes an aerobic MBBR tank, a reaction zone, and an equilibrium zone arranged in sequence along the water flow direction; the inlet end of the aerobic MBBR tank is connected to the anoxic MBBR tank, and the outlet end of the equilibrium zone is connected to the secondary treatment unit; the secondary treatment unit is used to perform flocculation sedimentation and filtration treatment on the sewage from the equilibrium zone; the sludge treatment unit is connected to the pretreatment unit, the biochemical treatment unit, and the secondary treatment unit respectively, and is used to centrally treat the sludge generated by each unit.

[0007] As a preferred embodiment, the bottom of the aerobic MBBR tank is provided with a nitrification reflux pipe, and the other end of the nitrification reflux pipe extends to the bottom of the anoxic MBBR tank; the nitrification reflux pipe is provided with a reflux pump for refluxing the mixed liquor in the aerobic MBBR tank back to the anoxic MBBR tank.

[0008] As a preferred embodiment, a first sludge return pipe is provided at the bottom of the equilibrium zone, and the other end of the first sludge return pipe extends to the inlet end of the anaerobic tank; a sludge pump is provided on the first sludge return pipe for returning the sludge in the equilibrium zone to the anaerobic tank.

[0009] As a preferred embodiment, both the aerobic MBBR tank and the anoxic MBBR tank are equipped with an aeration system at the bottom, and both tanks are filled with suspended carrier packing. The aeration system includes an air pump and multiple microporous aeration discs, which are evenly distributed at the bottom of the tank and connected to the air pump.

[0010] As a preferred embodiment, stainless steel screen structures are respectively installed at the top outlets of the anoxic MBBR tank and the aerobic MBBR tank; a perforated blow-off pipe is installed near the screen structure, and the perforated blow-off pipe is connected to an external air source for cleaning the adhering substances on the screen surface by airflow.

[0011] As a preferred embodiment, the secondary treatment unit includes: a stable effluent tank, a booster tank, a magnetic coagulation sedimentation tank, and a deep bed denitrification filter connected sequentially along the water flow direction; the inlet of the stable effluent tank is connected to the outlet of the equilibrium zone; the magnetic coagulation sedimentation tank is used to add magnetic powder and mix it with the sewage to form magnetic flocs; the deep bed denitrification filter is used to perform deep filtration and denitrification of the sewage after flocculation and sedimentation.

[0012] As a preferred embodiment, the secondary treatment unit further includes a second sludge return pipe and a magnetic separator; one end of the second sludge return pipe is connected to the bottom of the deep bed denitrification filter, and the other end extends into the magnetic coagulation sedimentation tank; a sludge pump and the magnetic separator are connected in series on the second sludge return pipe; the magnetic separator is used to separate the magnetic powder in the returned sludge and reuse it in the magnetic coagulation sedimentation tank, and discharge the remaining sludge to the sludge treatment unit.

[0013] As a preferred embodiment, the sludge treatment unit includes: a sludge storage tank and a sludge dewatering room connected in sequence; the sludge storage tank is connected to the first sludge return pipe, the sludge discharge port of the pretreatment unit, and the sludge hopper of the magnetic coagulation sedimentation tank through pipes; each connecting pipe is equipped with a sludge pump for transporting the collected sludge to the sludge storage tank.

[0014] As a preferred embodiment, the reaction zone is equipped with a stirring device to control the switching between the settling and suspension states of the sludge; the balance zone is equipped with a decanter to overflow the treated supernatant to the secondary treatment unit.

[0015] Compared with existing technologies, this invention utilizes a multi-stage coupled biochemical treatment system consisting of an anaerobic tank, an anoxic MBBR tank, and a CWSBR biological tank to form a complete biochemical chain of anaerobic phosphorus release – anoxic denitrification – aerobic nitrification phosphorus uptake. The nitrified liquor from the aerobic MBBR tank is returned to the anoxic MBBR tank via a nitrification return pipe, providing sufficient nitrate nitrogen for the denitrification reaction and significantly improving denitrification efficiency. Furthermore, the activated sludge from the equilibrium zone is returned to the anaerobic tank via a first sludge return pipe, ensuring the sludge concentration in the anaerobic tank matches the phosphorus release environment of polyphosphate-accumulating bacteria, simultaneously resolving the sludge age conflict. This achieves synergistic optimization of nitrogen and phosphorus removal; the secondary treatment unit adopts a combination of magnetic coagulation sedimentation tank and deep bed denitrification filter. The magnetic coagulation sedimentation tank forms high-density magnetic flocs by adding magnetic powder, which greatly improves sedimentation efficiency and phosphorus removal effect, shortens sedimentation time, and reduces the tank area; the deep bed denitrification filter can perform deep filtration and deep denitrification of wastewater; a centralized sludge treatment unit is set up to collect and treat all sludge generated by the pretreatment unit, biological treatment unit and secondary treatment unit in a unified manner, realizing centralized disposal and reduction of sludge, and simplifying the sludge treatment process. Attached Figure Description

[0016] Figure 1 This is a system block diagram of the integrated wastewater treatment system of this utility model; Figure 2 This is a diagram showing the equipment connection of a portion of the secondary treatment unit in the integrated wastewater treatment system of this utility model. Figure 3 This is a diagram showing the internal structure of the aerobic MBBR tank in the integrated wastewater treatment system of this utility model. Figure label: 1. Pretreatment unit; 2. Biochemical treatment unit; 3. Secondary treatment unit; 4. Sludge treatment unit; 5. Anaerobic tank; 6. Anoxic MBBR tank; 7. CWSBR biological tank; 8. Aerobic MBBR tank; 9. Reaction zone; 10. Balance zone; 11. Nitrification return pipe; 12. First sludge return pipe; 13. Microporous aeration disc; 14. Stabilized effluent tank; 15. Lifting water tank; 16. Magnetic coagulation sedimentation tank; 17. Deep bed denitrification filter; 18. Second sludge return pipe; 19. Sludge storage tank; 20. Sludge dewatering room. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0018] refer to Figure 1 Example 1: An integrated wastewater treatment system, comprising a pretreatment unit 1, a biochemical treatment unit 2, a secondary treatment unit 3, and a sludge treatment unit 4 connected in sequence.

[0019] Pretreatment unit 1 is an existing conventional sewage pretreatment facility, which can be one or more combinations of screens, grit chambers, and primary sedimentation tanks. It is mainly used to remove large suspended solids, sand and scum from sewage to avoid clogging and wear of equipment in subsequent treatment units. The effluent end of pretreatment unit 1 is connected to the influent end of biological treatment unit 2 through a pipeline.

[0020] Biological treatment unit 2 is the core pollutant degradation unit of the system, comprising an anaerobic tank 5, an anoxic MBBR tank 6, and a CWSBR biological tank 7 connected in sequence. Anaerobic tank 5 is a closed tank equipped with a submersible mixer to ensure uniform mixing of sludge and water and prevent sludge settling. In anaerobic tank 5, the wastewater completes the phosphorus release process by polyphosphate-accumulating bacteria, while simultaneously hydrolyzing large organic molecules in the wastewater into smaller organic molecules, providing an easily degradable carbon source for the subsequent denitrification reaction.

[0021] refer to Figure 1 The effluent outlet of anaerobic tank 5 is connected to the influent outlet of anoxic MBBR tank 6, and the effluent outlet of anoxic MBBR tank 6 is connected to the influent outlet of CWSBR biological tank 7. CWSBR biological tank 7 is a constant water level sequencing batch reactor, including aerobic MBBR tank 8, reaction zone 9 and equilibrium zone 10 arranged sequentially along the water flow direction; the influent outlet of aerobic MBBR tank 8 is connected to the effluent outlet of anoxic MBBR tank 6, and the effluent outlet of equilibrium zone 10 is connected to the influent outlet of secondary treatment unit 3.

[0022] refer to Figure 1The bottom of the aerobic MBBR tank 8 is equipped with a nitrification return pipe 11, and the other end of the nitrification return pipe 11 extends to the bottom of the anoxic MBBR tank 6. The nitrification return pipe 11 is equipped with a variable frequency return pump, which can precisely control the return ratio and return the nitrification mixture rich in nitrate nitrogen in the aerobic MBBR tank 8 to the anoxic MBBR tank 6 to provide nitrate nitrogen for denitrifying bacteria and enhance the denitrification effect. Preferably, the nitrification return pipe 11 can be flexibly adjusted according to the influent water quality and the total nitrogen index of the effluent.

[0023] The bottom of the balance zone 10 is provided with a first sludge return pipe 12, and the other end of the first sludge return pipe 12 extends to the inlet end of the anaerobic tank 5. A sludge pump is provided on the first sludge return pipe 12, which can return the activated sludge settled in the balance zone 10 to the anaerobic tank 5, ensuring the sludge concentration in the anaerobic tank 5, providing sufficient inoculum for phosphorus release by polyphosphate-accumulating bacteria, and solving the contradiction between nitrifying bacteria and polyphosphate-accumulating bacteria in sludge age.

[0024] refer to Figure 3 Both the aerobic MBBR tank 8 and the anoxic MBBR tank 6 are equipped with aeration systems at the bottom, and both tanks are filled with suspended carrier packing. The aeration system includes an air pump and multiple microporous aeration discs 13, which are evenly distributed at the bottom of the tank and connected to the air pump. The aeration system in the anoxic MBBR tank 6 is intermittent, mainly used for tank mixing and packing fluidization to prevent packing sedimentation and accumulation, while controlling the dissolved oxygen concentration in the tank at 0.2-0.5 mg / L to ensure an anaerobic denitrification environment. The aeration system in the aerobic MBBR tank 8 is continuous, controlling the dissolved oxygen concentration in the tank at 2-4 mg / L to provide sufficient oxygen for the aerobic nitrification reaction of nitrifying bacteria, while ensuring full fluidization of the packing. The suspended carrier packing material is preferably a hollow columnar packing material made of high-density polyethylene with a specific surface area greater than 500 m² / m³ and a filling rate of 30%-60%. A large number of microorganisms can attach and grow on the surface of the packing material to form a biofilm, which greatly increases the biomass of the tank. Stable biomass can be maintained without sludge return and has strong resistance to shock loads.

[0025] Stainless steel screen structures are installed at the top outlets of both the anoxic MBBR tank 6 and the aerobic MBBR tank 8. The pore size of the screen structure is smaller than the particle size of the suspended carrier packing, which can effectively intercept the suspended carrier packing in the tank and prevent the packing from being lost. A perforated blow-off pipe is installed near the screen structure. The perforated blow-off pipe is connected to an external high-pressure air source, which can periodically clean the adhering substances on the screen surface by airflow, so as to avoid screen blockage and ensure smooth water output.

[0026] The reaction zone 9 of the CWSBR biological tank 7 is equipped with a stirring device, which can control the alternation of aerobic, anoxic, and anaerobic environments in the reaction zone by switching between aeration and stirring, so as to achieve simultaneous nitrification and denitrification and further enhance the nitrogen and phosphorus removal effect. At the same time, the settling and suspension state of sludge can be switched by stirring. The balance zone 10 is equipped with a decanter, which can achieve continuous effluent with constant water level and stably overflow the treated supernatant to the secondary treatment unit 3, solving the problems of water level fluctuation and discontinuous effluent in the traditional SBR process.

[0027] refer to Figure 1 , Figure 2 The secondary treatment unit 3 is used to perform flocculation sedimentation and filtration for the wastewater from the equilibrium zone 10. It includes a stabilizing effluent tank 14, a lift tank 15, a magnetic coagulation sedimentation tank 16, and a deep-bed denitrification filter 17 connected sequentially along the water flow direction. The inlet of the stabilizing effluent tank 14 is connected to the outlet of the equilibrium zone 10 and is used to buffer and store the wastewater after biological treatment to ensure the stability of the influent for subsequent deep treatment. The outlet of the stabilizing effluent tank 14 is connected to the lift tank 15, which is equipped with a lift pump to quantitatively lift the wastewater into the magnetic coagulation sedimentation tank 16.

[0028] The magnetic coagulation sedimentation tank 16 includes a mixing zone, a flocculation zone, and a sedimentation zone. Magnetic powder and polyaluminum chloride (PAC) are added in the mixing zone, and polyacrylamide (PAM) is added in the flocculation zone. After the wastewater is fully mixed with the reagents and magnetic powder, high-density magnetic flocs are formed. Solid-liquid separation is quickly completed in the sedimentation zone, which greatly improves the removal efficiency of suspended solids and total phosphorus. The sedimentation efficiency is much higher than that of traditional sedimentation tanks, and the tank area can be significantly reduced.

[0029] The effluent end of the magnetic coagulation sedimentation tank 16 is connected to the deep bed denitrification filter 17. The deep bed denitrification filter 17 uses quartz sand filter media with a filter bed depth greater than 1.8m, which can perform deep filtration of wastewater after flocculation and sedimentation to remove residual suspended solids and colloidal substances in the water. At the same time, the deep bed denitrification filter 17 can add carbon source according to the total nitrogen requirements of the effluent to achieve deep denitrification and further reduce the total nitrogen concentration of the effluent, ensuring that the effluent water quality stably meets the Class A standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" GB18918-2002, and may even meet the reuse requirements of the Class IV surface water standard.

[0030] refer to Figure 2The secondary treatment unit 3 also includes a second sludge return pipe 18 and a magnetic separator. One end of the second sludge return pipe 18 is connected to the bottom of the deep bed denitrification filter 17, and the other end extends into the magnetic coagulation sedimentation tank 16. A sludge pump and a magnetic separator are connected in series on the second sludge return pipe 18. The backwash wastewater from the deep bed denitrification filter 17 and the discharged sludge from the magnetic coagulation sedimentation tank 16 are transported to the magnetic separator through the second sludge return pipe 18. The magnetic separator can efficiently separate the magnetic powder in the returned sludge. The separated magnetic powder is recycled back to the mixing zone of the magnetic coagulation sedimentation tank 16, which greatly reduces the cost of magnetic powder consumption. The remaining sludge after magnetic separation is discharged to the sludge treatment unit 4 for centralized disposal.

[0031] refer to Figure 1 , Figure 2 The sludge treatment unit 4 is connected to the pretreatment unit 1, the biochemical treatment unit 2, and the secondary treatment unit 3, respectively, for centralized treatment of the sludge generated by each unit. It includes a sludge storage tank 19 and a sludge dewatering room 20 connected in sequence. The sludge storage tank 19 is connected to the first sludge return pipe 12, the sludge discharge port of the pretreatment unit 1, and the sludge hopper of the magnetic coagulation sedimentation tank 16 via pipelines. Each connecting pipeline is equipped with a sludge pump, which can collect and transport the primary sludge generated by the pretreatment unit 1, the residual sludge generated by the biochemical treatment unit 2, and the chemical sludge generated by the secondary treatment unit 3 to the sludge storage tank 19 for homogenization and conditioning. The discharge end of the sludge storage tank 19 is connected to the sludge dewatering room 20, which is equipped with a plate and frame filter press or a belt dewatering machine to mechanically dewater the sludge, reducing the sludge moisture content to below 60%, forming sludge cakes for off-site disposal, thus achieving sludge reduction and harmlessness.

[0032] In operation, the wastewater first enters the pretreatment unit 1 to remove large particulate suspended solids, sand, and other impurities, and then flows by gravity into the anaerobic tank 5. In the anaerobic tank 5, after phosphorus release by polyphosphate-accumulating bacteria and hydrolysis of macromolecular organic matter, the wastewater enters the anoxic MBBR tank 6. Under anoxic conditions, denitrifying bacteria utilize the organic matter in the wastewater as a carbon source, reducing nitrate nitrogen in the nitrification return liquid to nitrogen gas, thus completing denitrification. Subsequently, the wastewater enters the CWSBR biological tank 7, flowing sequentially through the aerobic MBBR tank 8, reaction zone 9, and equilibrium zone 10. In the aerobic MBBR tank 8, organic matter degradation and ammonia nitrogen nitrification reactions are completed. The nitrate-rich mixed liquor is then returned to the anoxic MBBR tank 6 through the nitrification return pipe 11. In reaction zone 9, simultaneous nitrification and denitrification are achieved through switching between aeration and stirring, further degrading pollutants. In balance zone 10, sludge-water separation is completed. The supernatant is transported to secondary treatment unit 3 through a decanter, and the settled sludge is returned to anaerobic tank 5 through first sludge return pipe 12. After the effluent from balance zone 10 enters secondary treatment unit 3, it passes through stabilization effluent tank 14, lifting tank 15, magnetic coagulation sedimentation tank 16, and deep bed denitrification filter 17 in sequence to complete deep flocculation sedimentation, phosphorus removal, and filtration denitrification, and finally meets the discharge standards or is reused. All sludge generated by each unit of the system is transported to sludge treatment unit 4. After homogenization and conditioning in sludge storage tank 19, it enters sludge dewatering room 20 for dewatering and volume reduction, and finally the sludge cake is transported off-site for disposal.

[0033] The integrated wastewater treatment system in this embodiment achieves synergistic and efficient nitrogen and phosphorus removal through multi-level coupling of the biochemical treatment unit. It has strong resistance to shock loads, and combined with the deep purification of the secondary treatment unit, the effluent quality is stable and meets the standards. At the same time, it adopts centralized sludge treatment, which has a simple process and low operating costs.

[0034] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An integrated wastewater treatment system, characterized in that, include: The pretreatment unit (1), biochemical treatment unit (2), secondary treatment unit (3) and sludge treatment unit (4) are connected in sequence. The biochemical treatment unit (2) includes an anaerobic tank (5), an anoxic MBBR tank (6), and a CWSBR biological tank (7) connected in sequence. The CWSBR biological tank (7) includes an aerobic MBBR tank (8), a reaction zone (9), and a balance zone (10) arranged sequentially along the water flow direction. The inlet of the aerobic MBBR tank (8) is connected to the anoxic MBBR tank (6), and the outlet of the balance zone (10) is connected to the secondary treatment unit (3). The secondary treatment unit (3) is used to perform flocculation sedimentation and filtration treatment on the wastewater from the equilibrium zone (10); The sludge treatment unit (4) is connected to the pretreatment unit (1), the biochemical treatment unit (2) and the secondary treatment unit (3) respectively, and is used to centrally treat the sludge generated by each unit.

2. The integrated wastewater treatment system according to claim 1, characterized in that, The bottom of the aerobic MBBR tank (8) is provided with a nitrification return pipe (11), and the other end of the nitrification return pipe (11) extends to the bottom of the anoxic MBBR tank (6). The nitrification reflux pipe (11) is equipped with a reflux pump, which is used to reflux the mixed liquor in the aerobic MBBR tank (8) to the anoxic MBBR tank (6).

3. The integrated wastewater treatment system according to claim 2, characterized in that, The bottom of the balance zone (10) is provided with a first sludge return pipe (12), and the other end of the first sludge return pipe (12) extends to the water inlet of the anaerobic tank (5). The first sludge return pipe (12) is equipped with a sludge pump, which is used to return the sludge in the balance zone (10) to the anaerobic tank (5).

4. The integrated wastewater treatment system according to claim 3, characterized in that, Both the aerobic MBBR tank (8) and the anoxic MBBR tank (6) are equipped with an aeration system at the bottom, and both are filled with suspended carrier packing. The aeration system includes an air pump and multiple microporous aeration discs (13), which are evenly distributed at the bottom of the pool and connected to the air pump.

5. The integrated wastewater treatment system according to claim 4, characterized in that, The top outlets of the anoxic MBBR tank (6) and the aerobic MBBR tank (8) are respectively equipped with stainless steel screen structures. A perforated blow-off pipe is provided near the screen structure. The perforated blow-off pipe is connected to an external air source and is used to clean the adhering substances on the screen surface by airflow.

6. The integrated wastewater treatment system according to claim 5, characterized in that, The secondary processing unit (3) includes: The following are connected in sequence along the water flow direction: a stable effluent tank (14), a lift tank (15), a magnetic coagulation sedimentation tank (16), and a deep bed denitrification filter (17). The inlet of the stable outlet pool (14) is connected to the outlet of the balance zone (10); The magnetic coagulation sedimentation tank (16) is used to add magnetic powder and mix it with sewage to form magnetic flocs. The magnetic coagulation sedimentation tank (16) includes a mixing zone, a flocculation zone and a sedimentation zone. Magnetic powder and polyaluminum chloride are added in the mixing zone, and polyacrylamide is added in the flocculation zone. After the sewage is fully mixed with the reagents and magnetic powder, high-density magnetic flocs are formed, and solid-liquid separation is completed in the sedimentation zone. The deep bed denitrification filter (17) is used for deep filtration and denitrification of wastewater after flocculation and sedimentation; the outlet end of the magnetic coagulation sedimentation tank (16) is connected to the deep bed denitrification filter (17), which uses quartz sand filter media to perform deep filtration of wastewater after flocculation and sedimentation, and remove residual suspended solids and colloidal substances in the water; the deep bed denitrification filter (17) can add carbon source according to the total nitrogen requirements of the effluent to achieve deep denitrification and denitrification.

7. The integrated wastewater treatment system according to claim 6, characterized in that, The secondary treatment unit (3) also includes a second sludge return pipe (18) and a magnetic separator; One end of the second sludge return pipe (18) is connected to the bottom of the deep bed denitrification filter (17), and the other end extends into the magnetic coagulation sedimentation tank (16); A sludge pump and the magnetic separator are connected in series on the second sludge return pipe (18); The magnetic separator is used to separate the magnetic powder in the returned sludge and reuse it in the magnetic coagulation sedimentation tank (16), and discharge the remaining sludge to the sludge treatment unit (4).

8. The integrated wastewater treatment system according to claim 7, characterized in that, The sludge treatment unit (4) includes: The sludge storage tank (19) and the sludge dewatering room (20) are connected in sequence. The sludge storage tank (19) is connected to the first sludge return pipe (12), the sludge discharge port of the pretreatment unit (1), and the sludge hopper of the magnetic coagulation sedimentation tank (16) through pipes respectively. Sludge pumps are installed on the sludge transport pipelines to transport the collected sludge to the sludge storage tank (19).

9. The integrated wastewater treatment system according to claim 8, characterized in that, The reaction zone (9) is equipped with a stirring device to control the switching between the settling and suspension states of the sludge; The balance zone (10) is equipped with a decanter for overflowing the treated supernatant to the secondary treatment unit (3).

Images