System for the treatment of dairy wastewater

Abstract

The application relates to the technical field of sewage treatment, in particular to a dairy wastewater treatment system. The treatment system comprises a pretreatment unit, a biochemical treatment unit and a deep treatment unit arranged in sequence. The pretreatment unit is used for removing impurities in the dairy wastewater. The biochemical treatment unit comprises an anaerobic reactor, a multistage biological pool and a secondary sedimentation tank arranged in sequence. The multistage biological pool comprises a pre-anoxic zone, an anaerobic zone, an anoxic zone I, an aerobic zone I, a degassing zone I, an anoxic zone II, an aerobic zone II and a degassing zone II arranged in sequence. The pre-anoxic zone is located at the rear end of the anaerobic reactor, and the secondary sedimentation tank is located at the rear end of the degassing zone II. The deep treatment unit is used for treating total phosphorus and SS in the wastewater after the secondary sedimentation tank. The treatment system can stabilize the effluent quality to reach the standard, can meet the reuse water standard, can be reused for landscaping, road watering, river water replenishment, industrial enterprise circulating cooling water replenishment and the like, and can realize sewage resource utilization.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and more specifically, to a system for treating dairy wastewater. Background Technology

[0002] Dairy wastewater refers to the wastewater discharged during the production of condensed milk, cheese, cream, dairy soft drinks, ice cream, and dairy desserts. The wastewater mainly originates from the cleaning water used for containers and equipment, and its primary components include the raw materials used in the products.

[0003] Wastewater from cheese and cream processing is highly polluted, with COD levels... Cr The concentrations of pollutants in dairy wastewater are as high as 3000 mg / L, BOD5 as high as 2000 mg / L, total nitrogen as high as 90 mg / L, total phosphorus as high as 16 mg / L, oil and fat as high as 200 mg / L, and suspended solids as high as 600 mg / L. Therefore, the treatment of dairy wastewater is particularly difficult.

[0004] CN 217418471 U discloses a wastewater treatment system, comprising: a pretreatment unit, a biochemical reaction unit, and a subsequent sludge treatment unit. The pretreatment unit involves wastewater sequentially passing through a coarse screen and a booster pump station, a fine screen and an aerated grit chamber, before proceeding to a constant-level SBR biochemical tank for biochemical reaction. The biochemical reaction stage involves wastewater from the constant-level SBR biochemical tank sequentially passing through a mixing reaction sedimentation tank, a filter and a contact disinfection tank, and a Pasteurizer, before being discharged to the outside via an effluent booster pump. The subsequent sludge treatment unit involves sludge pumps in a sludge pumping station discharging sludge from the mixing reaction sedimentation tank and the constant-level SBR biochemical tank into a sludge storage tank. The sludge from the storage tank is then sequentially discharged into a sludge thickening room, a homogenizing tank, and a sludge dewatering room to be processed into sludge cakes and sent out. However, this treatment system is not effective for treating dairy wastewater, and its treatment effect is poor. Summary of the Invention

[0005] This application provides a dairy wastewater treatment system that can effectively treat dairy wastewater with better treatment results.

[0006] This application provides a treatment system for dairy wastewater, comprising a pretreatment unit, a biochemical treatment unit, and an advanced treatment unit arranged sequentially.

[0007] The pretreatment unit is used to remove impurities from dairy wastewater;

[0008] The biochemical treatment unit includes an anaerobic reactor, a multi-stage biological tank and a secondary sedimentation tank arranged in sequence. The multi-stage biological tank includes a pre-anoxic zone, an anaerobic zone, anoxic zone 1, aerobic zone 1, degassing zone 1, anoxic zone 2, aerobic zone 2 and degassing zone 2 arranged in sequence. The pre-anoxic zone is located at the rear end of the anaerobic reactor and the secondary sedimentation tank is located at the rear end of the degassing zone 2.

[0009] The advanced treatment unit is used to treat total phosphorus and suspended solids (SS) in wastewater after the secondary sedimentation tank.

[0010] In one embodiment of this application, the anaerobic zone, the anoxic zone 1, the degassing zone 1, the anoxic zone 2, and the degassing zone 2 are all equipped with stirring devices; the aerobic zone 1 and the anoxic zone 2 are both equipped with aeration devices.

[0011] In one embodiment of this application, both the first degassing zone and the second degassing zone are equipped with a reflux pump so that some of the wastewater passing through the second degassing zone is returned to the first degassing zone.

[0012] In one embodiment of this application, the biochemical treatment unit further includes a sludge return well for returning a portion of the sludge discharged from the secondary sedimentation tank to the pre-anoxic zone.

[0013] In one embodiment of this application, the advanced treatment unit includes a magnetic coagulation sedimentation tank, a sand filter, a contact disinfection tank, and a metering tank arranged in sequence. The magnetic coagulation sedimentation tank is located at the rear end of the secondary sedimentation tank and is used to remove total phosphorus from the wastewater. The sand filter is used to remove suspended solids (SS) from the wastewater. The metering tank is equipped with metering facilities for detecting the composition of the treated wastewater.

[0014] In one embodiment of this application, the treatment system further includes a sludge treatment unit, comprising a sludge storage tank, a sludge pumping station, a sludge thickening device, and a sludge dewatering device arranged in sequence. The sludge storage tank is used to collect the excess sludge discharged from the anaerobic reactor, the multi-stage biological tank, and the secondary sedimentation tank.

[0015] In one embodiment of this application, the treatment system further includes a deodorization unit for collecting odors generated in the coarse screen, fine screen, anaerobic zone, anoxic zone 1, anoxic zone 2, sludge storage tank, and sludge dewatering equipment.

[0016] In one embodiment of this application, the processing system further includes a biogas utilization unit for collecting biogas produced by the anaerobic reactor.

[0017] In one embodiment of this application, the processing system further includes an auxiliary unit, which includes a blower and a dosing device. The blower is used to provide oxygen to the aerobic zone 1 and aerobic zone 2. The dosing device is used to add PAC and PAM agents to the magnetic coagulation sedimentation tank and to add sodium hypochlorite to the contact disinfection tank.

[0018] The beneficial effects of this application are:

[0019] The pretreatment unit in the treatment system provided in this application can first remove most of the floating matter, grease, sand, and gravel from the dairy wastewater. Then, the wastewater sequentially passes through an anaerobic reactor, a multi-stage biological treatment tank, and a secondary sedimentation tank. The multi-stage biological treatment tank includes a pre-anoxic zone, an anaerobic zone, anoxic zone 1, aerobic zone 1, deaeration zone 1, anoxic zone 2, aerobic zone 2, and deaeration zone 2, arranged sequentially. The pre-anoxic zone is located at the rear end of the anaerobic reactor, and the secondary sedimentation tank is located at the rear end of the deaeration zone 2. Through this coordinated biological treatment unit, most of the COD in the dairy wastewater can be removed. Cr The wastewater contains BOD5, ammonia nitrogen, total nitrogen, total phosphorus, and suspended solids (SS). Then, a portion of the total phosphorus and SS in the dairy wastewater is further treated through a deep treatment unit, ensuring that the effluent quality consistently meets the standards for reuse. This allows the wastewater to be reused for landscaping, road watering, river replenishment, and industrial enterprise circulating cooling water replenishment, thus achieving the resource utilization of wastewater. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a process flow diagram of a dairy wastewater treatment system provided in an embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0026] In the description of the embodiments of this application, it should be noted that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, or the orientation or positional relationship commonly understood by those skilled in the art, and is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] In the description of the embodiments of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0028] This application addresses the COD of dairy wastewater. Cr The concentrations are 500–5000 mg / L, BOD5 is 200–2000 mg / L, ammonia nitrogen is 30–150 mg / L, total nitrogen is 50–200 mg / L, total phosphorus is 5–30 mg / L, SS is 10–500 mg / L, and pH is 3–10.

[0029] Figure 1 This is a process flow diagram of a dairy wastewater treatment system provided in an embodiment of this application. (See attached diagram.) Figure 1 The treatment system includes a pretreatment unit, a biochemical treatment unit, and an advanced treatment unit arranged in sequence; as well as a sludge treatment unit, a deodorization treatment unit, a biogas utilization unit, and an auxiliary unit.

[0030] The pretreatment unit includes a coarse screen, a lifting pool and pump station, a fine screen, an oil-water separator and grit chamber, and a regulating pool arranged in sequence. A lifting pump set is installed at the end of the regulating pool.

[0031] The corresponding pretreatment method is as follows: Dairy wastewater is collected through a pipe network and flows by gravity into a coarse screen. The coarse screen is a rotary screen with a filtration accuracy of 15mm, which can intercept larger floating objects and debris. Then, it enters a lift tank and remains there for 30 minutes. The lift tank is equipped with a submersible lift pump to lift the dairy wastewater to a fine screen. The fine screen is a stepped perforated plate screen with a filtration accuracy of 3mm. Next, it flows by gravity into an oil-water separator and grit chamber, where it remains for 5 minutes to separate grease and sand from the wastewater. The effluent from the oil-water separator and grit chamber flows by gravity into a regulating tank, where it remains for 8–12 hours to homogenize and regulate the flow rate. The regulating tank is equipped with a stirring device to prevent sedimentation, and a lift pump unit is located at the end of the regulating tank. The pretreatment unit primarily removes floating objects, grease, sand, and other impurities from the dairy wastewater.

[0032] The biochemical treatment unit includes an anaerobic reactor, a multi-stage biological tank, and a secondary sedimentation tank arranged in sequence. The multi-stage biological tank includes a pre-anoxic zone, an anaerobic zone, anoxic zone 1, aerobic zone 1, deaeration zone 1, anoxic zone 2, aerobic zone 2, and deaeration zone 2 arranged in sequence. The pre-anoxic zone is located at the rear end of the anaerobic reactor, and the secondary sedimentation tank is located at the rear end of the deaeration zone 2.

[0033] The corresponding biochemical treatment method is as follows: A booster pump unit lifts the wastewater to an anaerobic reactor, which is an upflow anaerobic sludge bed reactor with a retention time of 12–24 hours. After treatment in the anaerobic reactor, the COD of the dairy wastewater is reduced. CrThe wastewater is reduced by 80-90%, BOD5 by 70-80%, and SS by 30-50%. The effluent from the anaerobic reactor enters a multi-stage biological treatment tank. Dairy wastewater sequentially enters the pre-anoxic zone, anaerobic zone, anoxic zone 1, aerobic zone 1, deaeration zone 1, anoxic zone 2, aerobic zone 2, and deaeration zone 2, before entering the secondary sedimentation tank for sludge-water separation. The retention time in the multi-stage biological treatment tank is 15-30 hours. Agitation devices are installed in anoxic zones 1 and 2, anaerobic zones 1 and 2, and deaeration zones 1 and 2. Aeration devices are installed in aerobic zones 1 and 2. In the anoxic zones 1 and 2, denitrification is achieved (nitrate nitrogen and nitrite nitrogen are reduced to nitrogen gas by denitrifying bacteria). In the anaerobic zones 1 and 2, phosphorus is released by microorganisms. In the aerobic zones 1 and 2, nitrification (ammonia nitrogen is first converted to nitrite nitrogen, and then nitrite nitrogen is converted to nitrate nitrogen) and phosphorus absorption by microorganisms are achieved. In the deaeration zones 1 and 2, dissolved oxygen in the water is removed. The degassing zones 1 and 2 are equipped with internal return pumps, using a through-wall pump design, to allow a portion of the wastewater passing through zone 2 to return to zone 1, with a return ratio of 200–400%. An effluent weir is installed at the end of zone 2 to control the liquid level in the multi-stage biological tank, maintaining the sludge concentration in the multi-stage biological tank at 4000–6000 mg / L. The effluent from the multi-stage biological tank enters the secondary sedimentation tank by gravity. The secondary sedimentation tank is a circular tank with circumferential inlet and outlet, and a sedimentation loading rate of 0.8–1.2 m³. 3 / m 2 The sludge from the secondary sedimentation tank is discharged into the sludge return well to return a portion of the sludge discharged from the secondary sedimentation tank to the pre-anoxic zone, with a return ratio of 50-100%. The remaining sludge is discharged into the sludge storage tank of the sludge treatment unit. The biological treatment unit mainly removes most of the COD from the dairy wastewater. Cr BOD5, ammonia nitrogen, total nitrogen, total phosphorus, SS, etc.

[0034] The advanced treatment unit includes a magnetic coagulation sedimentation tank, a sand filter, a contact disinfection tank, and a metering tank arranged in sequence, with the magnetic coagulation sedimentation tank located at the rear end of the secondary sedimentation tank.

[0035] The corresponding advanced treatment method is as follows: the effluent from the secondary sedimentation tank enters the magnetic coagulation sedimentation tank, PAC and PAM agents are added at the inlet, and a mixer is installed for mixing. The sedimentation load of the magnetic coagulation sedimentation tank is 15-20 m³ / h. 3 / m 2The primary treatment unit removes total phosphorus from dairy wastewater, ensuring effluent total phosphorus <0.3 mg / L. The effluent from the magnetic coagulation sedimentation tank enters a sand filter, which is a downward flow filter using natural quartz sand as the filter media. The filtration velocity is 6–9 m / h, primarily removing suspended solids (SS) to achieve effluent SS <5 mg / L. The sand filter is equipped with backwashing equipment, employing an air-water wash-air wash cycle. The effluent from the sand filter flows by gravity into a contact disinfection tank, with a residence time of 20–60 minutes, where sodium hypochlorite solution is added for disinfection. Finally, the effluent from the contact disinfection tank passes through a metering system in a metering tank to test the effluent quality and confirm compliance with discharge and reuse standards. The metering system uses a Busbar metering tank or an electromagnetic flow meter. The advanced treatment unit primarily removes total phosphorus and SS from the dairy wastewater. After the advanced treatment unit, the effluent COD... Cr <30mg / L, BOD5<6mg / L, ammonia nitrogen<2.5mg / L, total nitrogen<15mg / L, total phosphorus<0.3mg / L, SS<5mg / L, pH 6-9.

[0036] In this application, the sludge treatment unit includes a sludge storage tank, a sludge pumping station, sludge thickening equipment, and sludge dewatering equipment arranged sequentially. The sludge storage tank is used to collect excess sludge discharged from the anaerobic reactor, multi-stage biological tank, and secondary sedimentation tank, controlling the sludge concentration in the multi-stage biological tank between 4000 and 6000 mg / L. The sludge can be dewatered using the sludge dewatering equipment to achieve a sludge moisture content of <60%, allowing the sludge to be used for landscaping, garden construction, soil improvement, etc.

[0037] In this application, the deodorization treatment unit is used to collect odorous gases generated in the coarse screen, fine screen, anaerobic zone, anoxic zone 1, anoxic zone 2, sludge storage tank, and sludge dewatering equipment; biological deodorization technology is used for treatment, and the gases are ultimately discharged in compliance with standards.

[0038] In this application, the biogas utilization unit is used to collect biogas produced by the anaerobic reactor; it is stored in a biogas tank and, after purification, can be used in a biogas boiler.

[0039] In this application, the auxiliary unit includes a blower and a dosing device. The blower is used to provide oxygen to the aerobic zone 1 and aerobic zone 2, so that the air-to-water ratio of aerobic zone 1 and aerobic zone 2 is 4 to 10:1. The dosing device is used to add PAC and PAM agents to the magnetic coagulation sedimentation tank, and to add sodium hypochlorite to the contact disinfection tank.

[0040] The deodorization unit, biogas utilization unit, and auxiliary unit are all existing treatment units, and will not be described in detail here. The main difference is their installation location.

[0041] By using this treatment system and method to treat dairy wastewater, the following effects can be achieved:

[0042] (1) The dairy wastewater treatment method has a strong impact resistance and the effluent quality can meet the standards. It can be reused for landscaping, road watering, river replenishment, and industrial enterprise circulating cooling water replenishment, and can realize the resource utilization of sewage.

[0043] (2) This method of treating dairy wastewater does not require the addition of a carbon source, has a small amount of reagent consumption, and has a low operating cost.

[0044] (3) The biogas generated by the system is fully utilized by this dairy wastewater treatment method. After purification, it can be used in biogas boilers, saving energy and reducing carbon emissions.

[0045] (4) The dairy wastewater treatment method is environmentally friendly. The odor generated by the system is collected and treated by biological deodorization technology, and finally discharged in compliance with standards, with no odor overflow.

[0046] (5) The sludge produced by this dairy wastewater treatment method can be used for land greening, garden construction, soil improvement, etc. after dewatering treatment (moisture content <60%), thus realizing the resource utilization of sludge.

[0047] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0048] Example 1

[0049] The wastewater is mainly dairy wastewater from Mengniu Company. After being collected through the pipeline network, the dairy wastewater flows into a rotary coarse screen by gravity, with a filtration accuracy of 15mm. Then, it enters the lifting tank and stays for 30 minutes. Using a submersible lift pump, the dairy wastewater is lifted to a stepped perforated fine screen with a filtration accuracy of 3mm. Then, it flows into the oil-water separator and grit chamber by gravity and stays for 5 minutes. The effluent from the oil-water separator and grit chamber flows into the equalization tank equipped with a stirring device by gravity and stays for 10 hours.

[0050] Wastewater is pumped to the anaerobic reactor via a lift pump unit at the end of the equalization tank, where it remains for 20 hours. The effluent from the anaerobic reactor then enters a multi-stage biological treatment tank, sequentially passing through the pre-anoxic zone, anaerobic zone, anoxic zone 1, aerobic zone 1, deaeration zone 1, anoxic zone 2, aerobic zone 2, and deaeration zone 2, before entering a secondary sedimentation tank for sludge-water separation. The multi-stage biological treatment tank has a retention time of 25 hours, passing through anoxic zone 1 and anoxic zone 2, anaerobic zone 1 and anaerobic zone 2, and deaeration zone 1 and deaeration zone 2. A mixing device is installed, and aeration devices are installed in both aerobic zone 1 and aerobic zone 2. Both deaeration zones 1 and 2 are equipped with through-wall return pumps to allow a portion of the wastewater passing through deaeration zone 2 to return to deaeration zone 1, with a return ratio of 300%. An effluent weir is installed at the end of deaeration zone 2 to control the liquid level in the multi-stage biological tank. The sludge concentration in the multi-stage biological tank is controlled at 4000–6000 mg / L. The effluent from the multi-stage biological tank enters by gravity into a circular secondary sedimentation tank with a sedimentation load of 1.0 m³. 3 / m 2 "h" The sludge from the secondary sedimentation tank is discharged into the sludge return well, which is used to return part of the sludge discharged from the secondary sedimentation tank to the pre-anoxic zone. The return ratio is 80%. The remaining sludge is discharged into the sludge storage tank of the sludge treatment unit.

[0051] The effluent from the secondary sedimentation tank enters the magnetic coagulation sedimentation tank. PAC and PAM reagents are added at the inlet, and a mixer is installed for mixing. The sedimentation load of the magnetic coagulation sedimentation tank is 18m³. 3 / m 2 The effluent from the magnetic coagulation sedimentation tank enters the downward flow filter tank, where natural quartz sand is used as the filter media, and the filtration speed is 8 m / h. The sand filter tank is equipped with a backwashing device, which adopts an air wash-air-water wash-water wash working mode. The effluent from the sand filter tank flows into the contact disinfection tank by gravity and stays for 30 minutes, where sodium hypochlorite solution is added for disinfection. Finally, the effluent from the contact disinfection tank passes through the metering facilities in the metering tank to test the effluent quality.

[0052] The experimental results are shown in Table 1.

[0053] Table 1. Water quality data of influent and effluent in the experiment.

[0054]

[0055] As can be seen from Table 1, the method provided in this application has a very good effect on the treatment of dairy wastewater, and it can be directly discharged in compliance with standards.

[0056] Comparative Example 1

[0057] The wastewater is mainly dairy wastewater from Mengniu Company. After being collected through the pipeline network, the dairy wastewater flows into a rotary coarse screen by gravity, with a filtration accuracy of 15mm. Then, it enters the lifting tank and stays for 30 minutes. Using a submersible lift pump, the dairy wastewater is lifted to a stepped perforated fine screen with a filtration accuracy of 3mm. Then, it flows into the oil-water separator and grit chamber by gravity and stays for 5 minutes. The effluent from the oil-water separator and grit chamber flows into the equalization tank equipped with a stirring device by gravity and stays for 10 hours.

[0058] Wastewater is pumped to the SBR biological treatment tank via a booster pump unit at the end of the regulating tank for aeration for 45 hours. It then enters the magnetic coagulation sedimentation tank, where PAC and PAM reagents are added at the inlet, and a mixer is installed for mixing. The sedimentation load of the magnetic coagulation sedimentation tank is 18 m³ / h. 3 / m 2 The effluent from the magnetic coagulation sedimentation tank enters the downward flow filter tank, where natural quartz sand is used as the filter media, and the filtration speed is 8 m / h. The sand filter tank is equipped with a backwashing device, which adopts an air wash-air-water wash-water wash working mode. The effluent from the sand filter tank flows into the contact disinfection tank by gravity and stays for 30 minutes, where sodium hypochlorite solution is added for disinfection. Finally, the effluent from the contact disinfection tank passes through the metering facilities in the metering tank to test the effluent quality.

[0059] The experimental results are shown in Table 2.

[0060] Table 2. Water quality data of influent and effluent in the experiment.

[0061]

[0062] As can be seen from Table 2, the method provided in Comparative Example 1 is not effective in treating dairy wastewater. Some indicators can meet the national Class A standard, but ammonia nitrogen and total nitrogen cannot meet the standard.

[0063] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A dairy wastewater treatment system, characterized in that, The system includes a pretreatment unit, a biochemical treatment unit, and an advanced treatment unit arranged sequentially. The pretreatment unit is used to remove impurities from dairy wastewater. The biochemical treatment unit includes an anaerobic reactor, a multi-stage biological tank, and a secondary sedimentation tank arranged sequentially. The multi-stage biological tank includes a pre-anoxic zone, an anaerobic zone, an anoxic zone I, an aerobic zone I, a degassing zone I, an anoxic zone II, an aerobic zone II, and a degassing zone II arranged sequentially. The pre-anoxic zone is located at the rear end of the anaerobic reactor, and the secondary sedimentation tank is located at the rear end of the degassing zone II. The advanced treatment unit is used to treat the total phosphorus and suspended solids (SS) in the wastewater after passing through the secondary sedimentation tank. Both the first degassing zone and the second degassing zone are equipped with reflux pumps to allow some of the wastewater passing through the second degassing zone to flow back into the first degassing zone.

2. The processing system according to claim 1, characterized in that, The anaerobic zone, the anoxic zone 1, the degassing zone 1, the anoxic zone 2, and the degassing zone 2 are all equipped with stirring devices; the aerobic zone 1 and the anoxic zone 2 are both equipped with aeration devices.

3. The processing system according to claim 1, characterized in that, The biochemical treatment unit also includes a sludge return well, which is used to return a portion of the sludge discharged from the secondary sedimentation tank to the pre-anoxic zone.

4. The processing system according to any one of claims 1 to 3, characterized in that, The pretreatment unit includes a coarse screen, a lifting tank and pump station, a fine screen, an oil-water separator and grit chamber, and an equalization tank arranged in sequence. The end of the equalization tank is equipped with a lifting pump set for lifting the wastewater into the anaerobic reactor.

5. The processing system according to claim 4, characterized in that, The advanced treatment unit includes a magnetic coagulation sedimentation tank, a sand filter, a contact disinfection tank, and a metering tank arranged in sequence. The magnetic coagulation sedimentation tank is located at the rear end of the secondary sedimentation tank and is used to remove total phosphorus from the wastewater. The sand filter is used to remove suspended solids (SS) from the wastewater. The metering tank is equipped with metering facilities for detecting the composition of the treated wastewater.

6. The processing system according to claim 5, characterized in that, The treatment system also includes a sludge treatment unit, comprising a sludge storage tank, a sludge pumping station, a sludge thickening device, and a sludge dewatering device arranged in sequence. The sludge storage tank is used to collect the excess sludge discharged from the anaerobic reactor, the multi-stage biological tank, and the secondary sedimentation tank.

7. The processing system according to claim 6, characterized in that, The treatment system also includes an odor treatment unit for collecting odors generated in the coarse screen, the fine screen, the anaerobic zone, the anoxic zone 1, the anoxic zone 2, the sludge storage tank, and the sludge dewatering equipment.

8. The processing system according to claim 1, characterized in that, The treatment system also includes a biogas utilization unit for collecting biogas produced by the anaerobic reactor.

9. The processing system according to claim 6, characterized in that, The treatment system also includes an auxiliary unit, which includes a blower and a dosing device. The blower is used to provide oxygen to the aerobic zone 1 and the aerobic zone 2. The dosing device is used to add PAC and PAM agents to the magnetic coagulation sedimentation tank and to add sodium hypochlorite to the contact disinfection tank.

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