Denitrification and dephosphorization separated integrated sewage treatment system and method

Abstract

The invention discloses a denitrification and dephosphorization separated integrated sewage treatment system and a denitrification and dephosphorization separated integrated sewage treatment method. The system comprises a grating, a water collecting tank, biochemical equipment I, biochemical equipment II, magnetic precipitation equipment, a sludge dewatering room and a sludge storage tank, the first biochemical device is an A / O process denitrification device, the second biochemical device is an A / O process biofilm process denitrification device, and the magnetic precipitation device is a flocculation precipitation method magnetic precipitation device; sewage is fed in sections, part of the fed water enters the anoxic zone of the biochemical equipment I, and the rest of the fed water enters the anoxic zone of the biochemical equipment II; no sewage backflow equipment is arranged between the first biochemical equipment and the second biochemical equipment, and nitrification liquid of the first biochemical equipment completely enters the anoxic zone of the second biochemical equipment for denitrification. According to the system and the method, the spatial separation of phosphorus removal bacteria, denitrifying bacteria and nitrifying bacteria is realized, the contradiction of sludge age is solved, relatively high denitrification efficiency is achieved under the condition of not additionally adding a carbon source, and the treatment effects of nitrogen removal and phosphorus removal are synchronously improved.

Description

Technical Field

[0001] The present application relates to the technical field of sewage treatment, and in particular to an integrated sewage treatment system and method for separate nitrogen removal and phosphorus removal. Background Art

[0002] The problem of eutrophication of water bodies was raised in the mid-20th century. Unrestricted discharge of sewage containing nitrogen and phosphorus has led to excessive reproduction of algae in the receiving water bodies and deterioration of water quality. The pollution of raw water by nitrogen and phosphorus has increased the difficulty and cost of water treatment. Therefore, removing nutrients such as nitrogen and phosphorus from sewage has become one of the main processes for sewage treatment. The traditional A2 / O (Anaerobic-Anoxic-Oxic) process, namely the anaerobic-anoxic-aerobic method, has been widely used because it can complete the functions of nitrogen removal and phosphorus removal in the same system, has a simple process, and is easy to operate and manage. It is currently the mainstream process for biological nitrogen removal and phosphorus removal.

[0003] However, the process faces contradictions in carbon source, nitrate, sludge age, etc., and it is difficult to improve the nitrogen removal and phosphorus removal effects simultaneously. In the traditional A2 / O nitrogen removal and phosphorus removal system, the carbon source is mainly consumed in phosphorus release, denitrification and normal metabolism of heterotrophic bacteria. Among them, the phosphorus release and denitrification rates are closely related to the content of the easily degradable part in the influent carbon source. Conventional A2 / O sewage biological treatment processes usually require the establishment of anaerobic tanks, anoxic tanks and aerobic tanks to achieve the purpose of nitrogen removal and phosphorus removal. And internal reflux of the mixed liquor is required to supplement the carbon source, which will increase the operating costs of sewage treatment. The sludge age of the A2 / O process system is affected by two aspects: on the one hand, the minimum specific growth rate of autotrophic nitrifying bacteria is much lower than that of heterotrophic aerobic bacteria. In order for nitrifying bacteria to survive and become the dominant bacterial community, the sludge age must be long; on the other hand, since phosphorus removal is mainly achieved by removing the residual sludge containing high phosphorus, if the time is too long, the amount of residual sludge discharged every day that requires high phosphorus content is too small, and a high phosphorus removal efficiency cannot be achieved. At the same time, too high sludge age will cause phosphorus to be released again from the sludge, further reducing the phosphorus removal efficiency. In summary, the denitrification and phosphorus removal functions of the A2 / O process are in conflict and competition with the sludge age and carbon source, and it is difficult to remove nitrogen and phosphorus efficiently in the same system at the same time.

[0004] Therefore, in order to simultaneously improve the effects of nitrogen removal and phosphorus removal, it is necessary to improve the structure and treatment methods of the sewage system. Summary of the invention

[0005] In order to overcome the defects of the prior art in the background technology, the present invention proposes an integrated sewage treatment system and method with separate denitrification and phosphorus removal, and changes the traditional A2 / O process to separate the denitrification and phosphorus removal processes into two different systems, thereby realizing the spatial separation of phosphorus removal bacteria and denitrifying bacteria and nitrifying bacteria, and designing a segmented water inlet process to achieve the purpose of solving the sludge age contradiction and carbon source shortage problems; at the same time, combined with the efficient structural design of the aeration system, the design of biofilm method special-shaped fillers, and the circulation design of the entire system, an integrated sewage treatment system is formed to simultaneously improve the treatment effects of denitrification and phosphorus removal.

[0006] The technical solution of the present invention is: An integrated sewage treatment system with separate denitrification and phosphorus removal, including a grille and a water collection tank, a biochemical device 1, a biochemical device 2, a magnetic precipitation device, a sludge dewatering room, and a sludge storage tank; the biochemical device 1 is an A / O process denitrification device, the biochemical device 2 is an A / O process biofilm denitrification device, and the magnetic precipitation device is a flocculation precipitation method magnetic precipitation device; sewage flows into the grille and the water collection tank, and then flows into the biochemical device 1, the biochemical device 2, and the magnetic precipitation device in turn for treatment, the water that meets the purification standard flows out of the magnetic precipitation device, and the sludge flows from the magnetic precipitation device to the sludge dewatering room and the sludge storage tank in turn and is transported out; The integrated sewage treatment system with separate denitrification and phosphorus removal, the biochemical equipment one includes an anoxic zone and an aerobic zone, the biochemical equipment two includes an anoxic zone and an aerobic zone, the magnetic precipitation equipment includes a coagulation device and a sedimentation tank; sewage is fed in sections, part of the water enters the anoxic zone of the biochemical equipment one, and the rest of the water enters the anoxic zone of the biochemical equipment two; there is no sewage return equipment between the biochemical equipment one and the biochemical equipment two, and the nitrification liquid of the biochemical equipment one completely enters the anoxic section of the biochemical equipment two for denitrification.

[0007] Furthermore, the sedimentation tank of the magnetic sedimentation equipment is provided with a sludge return pipe, and the sludge that needs to be repeatedly treated flows back to the coagulation device for magnetic sedimentation treatment; a filtrate tank and a sludge tank are also provided, and the waste liquid generated by dehydration in the sludge dehydration room flows to the filtrate tank for filtration, the sludge settles into the sludge tank, and the filtered waste liquid flows back to the collection tank.

[0008] Specifically, the anoxic zone of the biochemical equipment 1 includes a water inlet 1, a water inlet 2, and a pretreatment component, and the aerobic zone includes a three-phase separator, a three-phase separator bracket, an overflow weir, an overflow weir bracket, an air outlet pipe 1, a water outlet trough 1, a water outlet pipe 1, an aeration system 1, and an aeration system 2; it also includes a water guide pipe, through which water is guided between the anoxic zone and the aerobic zone; it also includes a perforated mud discharge pipe.

[0009] Specifically, the anoxic zone of the biochemical equipment 2 includes water inlet 3, water inlet 4, and a water distribution trough, and the aerobic zone includes a float, baffle 1, baffle 2, baffle 3, water outlet trough 2, water outlet 2, baffle support columns, and aeration system 3; both the anoxic zone and the aerobic zone are provided with special-shaped fillers, combined fillers and filler frames.

[0010] Specifically, the magnetic sedimentation equipment includes an inlet weir, a rapid mixing reaction tank, a magnetic medium mixing reaction tank, a flocculation reaction tank, a magnetic mud sedimentation tank, a residual magnetic mud pump, a reflux magnetic mud pump, and a magnetic recovery machine; the water to be treated enters the rapid mixing reaction tank, the magnetic medium mixing reaction tank, the flocculation reaction tank in sequence, and then enters the sedimentation tank, and is discharged from the sump at the top of the sedimentation tank after treatment; part of the magnetic mud in the bottom sludge area is returned to the magnetic medium coagulation reaction tank through the reflux magnetic mud pump, and the remaining part enters the magnetic recovery machine.

[0011] The present invention also provides an integrated sewage treatment method for separate denitrification and phosphorus removal, comprising the following steps: S1, sewage from the municipal pipe network is separated by coarse, medium and fine screens to remove coarse and fine floating objects, and then lifted to the biochemical equipment through the lifting pump of the collection tank; the screen residue separated by the screen is cleaned regularly by the operating personnel.

[0012] S2, the interior of the biochemical equipment is divided into two levels of A / O. At the same time, the sewage enters the anoxic zone and aerobic zone in the biological pool in multiple sections, so that the carbon source in the sewage can be selectively supplied to different functional areas. The nitrification liquid of biochemical equipment one enters the anoxic zone of biochemical equipment two to achieve denitrification and denitrification, and nitrification is achieved again in the aerobic zone to remove the remaining ammonia nitrogen.

[0013] S3, the wastewater after biochemical treatment enters the rapid mixing tank of the magnetic sedimentation equipment, where coagulant, magnetic powder and PAM are added. After sedimentation, solid-liquid separation is performed to remove SS and total phosphorus.

[0014] S4, the remaining sludge from the high-efficiency sedimentation equipment is pumped to the high-efficiency cutting machine by a cutting pump. After the magnetic powder is recovered, the remaining sludge flows to the sludge pool by gravity, and is pumped to the screw stacking dehydrator for mechanical dehydration by a screw pump. It is further concentrated and dehydrated by adding PAM (cationic). After dehydration, the sludge moisture content reaches about 85% and is then transferred to the sludge storage tank for regular external disposal.

[0015] Furthermore, the step S3 further includes: S31, the water to be treated is lifted by the pump to the coagulation system, first enters the rapid mixing reaction tank, and the coagulant is added in a certain proportion and fully mixed, then flows into the magnetic medium mixing reaction tank by gravity, and the magnetic medium and the return magnetic mud are added. After being stirred at a uniform speed by the mixer to form small flocs, it enters the flocculation reaction tank, and then the coagulant aid is added in a certain proportion. After being mixed evenly, a dense floc wrapped around the magnetic medium is formed.

[0016] S32, the dense flocs wrapped with magnetic media enter the sedimentation tank and quickly settle to the sludge area at the bottom of the tank under the action of gravity. The tiny flocs that are not easy to settle are captured by the inclined tube, and finally high-quality clean water is discharged from the overflow of the sump at the top of the sedimentation tank. Part of the magnetic mud in the bottom sludge area is returned to the magnetic medium coagulation reaction tank through the magnetic mud pump, and the rest enters the magnetic medium recovery system.

[0017] S33, the remaining magnetic mud is first dispersed into magnetic medium and residual mud residue by the deflocculant, and the magnetic medium is recovered by the magnetic recovery machine to the magnetic medium mixing reaction tank for recycling, and the remaining mud residue enters the sludge dewatering treatment system.

[0018] The beneficial effects of the technical solution of the present invention are: 1. In view of the fact that biological denitrification and phosphorus removal are biochemical treatment processes carried out by two completely different types of microorganisms, and have different requirements for environmental factors, in order to meet the different growth conditions and environmental requirements of phosphorus removal bacteria, nitrifying bacteria, and denitrifying bacteria, the present invention changes the traditional A2 / O process into a new combined process of two-stage series A / O plus magnetic precipitation phosphorus removal, and divides the denitrification and phosphorus removal processes into two different systems. The first-stage A / O and the second-stage A / O use biofilm denitrification, and the third-stage magnetic precipitation phosphorus removal, which realizes the spatial separation of phosphorus removal bacteria, denitrifying bacteria, and nitrifying bacteria, and achieves the purpose of solving the sludge age contradiction.

[0019] 2. The present invention adopts a two-stage series A / O segmented water inlet process, in which part of the inlet water enters the first-stage A / O anoxic zone, and the rest of the inlet water enters the second-stage A / O anoxic zone, thus forming a pollutant concentration gradient in the two-stage reactor. Due to the segmented water inlet, the nitrified liquid produced in the aerobic zone of the first-stage A / O in the system directly enters the denitrification zone of the second-stage A / O for denitrification. The system does not need to design and set up internal reflux pipes and reflux pumps for the nitrified liquid, and the organic matter in the inlet water can be used as a carbon source in the denitrification zone, so that a higher denitrification efficiency can be achieved without adding an external carbon source. The reflux of the nitrified mixed liquid is eliminated in the system process flow, which can save the power consumption of the reflux pump compared with the traditional A / O process. The segmented water inlet process of the two-stage series A / O can more reasonably distribute the carbon source and reduce investment costs and operating costs.

[0020] 3. The present invention combines the efficient structural design of the aeration system, the design of the biofilm method special-shaped filler, and the circulation design of the entire system to form an integrated sewage treatment system, thereby simultaneously improving the treatment effects of nitrogen removal and phosphorus removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a concise process flow chart of the present invention; Figure 2 It is a detailed process flow chart of the present invention; Figure 3 It is a schematic diagram of the structure of biochemical equipment 1; Figure 4 It is a schematic diagram of the structure of biochemical equipment 2; Figure 5 It is a structural schematic diagram of the magnetic precipitation equipment.

[0022] Notes in the figure: 101, water inlet 1; 102, water inlet 2; 103, pretreatment component; 104, water guide pipe; 105, three-phase separator; 106, overflow weir; 107, three-phase separator bracket; 108, overflow weir bracket; 109, air outlet pipe 1; 110, water outlet trough 1; 111, water outlet pipe 1; 112, perforated mud discharge pipe; 113, aeration system 1; 114, aeration system 2; 201, water inlet 3; 202, water inlet 4; 203, water distribution trough; 204, buoy; 205, partition 1; 20 6. Partition 2; 207. Partition 3; 208. Water outlet 2; 209. Water outlet 2; 210. Special-shaped filler in zone B; 211. Partition support column; 212. Special-shaped filler in zone D; 213. Aeration system 3; 214. Combined filler; 215. Filler frame; 216. Special-shaped filler in zone A; 301. Water inlet weir; 302. Rapid mixing reaction tank; 303. Magnetic medium mixing reaction tank; 304. Flocculation reaction tank; 305. Magnetic mud sedimentation tank; 306. Residual magnetic mud pump; 307. Reflux magnetic mud pump; 308. Magnetic recovery machine. DETAILED DESCRIPTION

[0023] A specific embodiment will be provided below in conjunction with the accompanying drawings of the present invention to clearly and completely describe the technical solution of the present invention.

[0024] The present application provides a specific embodiment, taking a sewage treatment project for a heavily polluted water body in a drainage ditch as an example, the sewage treatment scale is 20,000 m³ / d.

[0025] See also Figure 1-2 The concise process flow chart and detailed process flow chart are provided. The main process of sewage treatment in this embodiment adopts: screen / water collection tank → biochemical equipment → magnetic precipitation equipment, and the effluent is discharged to the receiving water body after meeting the standards.

[0026] After the sewage from the municipal pipe network is separated by coarse, medium and fine screens to remove coarse and fine floating objects, it is lifted to the biochemical equipment through the lifting pump of the water collection tank. The biochemical equipment is divided into two levels of A / O. At the same time, the sewage enters the anoxic zone and aerobic zone in the biological pool in multiple sections, so that the carbon source in the sewage can be selectively supplied to different functional areas. The nitrification liquid of biochemical equipment 1# enters the anoxic zone of biochemical equipment 2# to achieve denitrification and denitrification, and nitrification is achieved again in the aerobic zone to remove the remaining ammonia nitrogen. The sewage after biochemical treatment enters the rapid mixing tank of the magnetic precipitation equipment, where coagulants, magnetic powders and PAM are added. After precipitation, solid-liquid separation is performed to remove SS and total phosphorus.

[0027] The screen residue separated by the screen is cleaned regularly by the operating personnel.

[0028] The remaining sludge from the high-efficiency sedimentation equipment is pumped to the high-efficiency cutting machine by a cutting pump. After the magnetic powder is recovered, the remaining sludge flows to the sludge pool by gravity and is pumped to the screw stacking dehydrator for mechanical dehydration by a screw pump. It is further concentrated and dehydrated by adding PAM (cationic). After dehydration, the sludge moisture content reaches about 85% and is then transferred to the sludge storage tank for regular external disposal.

[0029] See the structural diagram of biochemical equipment 1 for details. Figure 3 , using a multi-stage AO process, the sewage is divided into multiple sections and enters the anoxic zone and aerobic zone in the biological pool, so that the carbon source in the sewage can be selectively supplied to different functional areas, and is preferentially used for denitrification and denitrification, which can effectively save carbon sources. At the same time, it can also increase the sludge concentration and reduce the volume of the biological pool. Multi-stage AO series connection can eliminate the internal reflux equipment, and the nitrification liquid of biochemical equipment 1# completely enters the anoxic section of biochemical equipment 2# for denitrification, which strengthens the denitrification effect and improves the denitrification efficiency. In short, the multi-stage and multi-stage AO process can more reasonably allocate carbon sources and reduce investment and operating costs.

[0030] Biochemical equipment-design parameters: Hypoxic period residence time: 0.5h Aerobic residence time: 2.5h Nitrification volume load: 0.08kgNH3-N / m 3 ·d COD volume load: 1.60kgCOD / m 3 ·d See the structural diagram of biochemical equipment 2 for details. Figure 4The biological contact oxidation process is also known as "submerged biofilter", "contact aeration method" and "fixed activated sludge method". Its technical essence is to fill the biological reaction tank with fillers. The oxygenated sewage submerges all the fillers and flows through the fillers at a certain flow rate. Some microorganisms grow on the surface of the fillers in the form of biofilms, while some grow in the form of flocculent suspension in the sewage and have extensive contact with the biofilm. Under the action of the metabolism of microorganisms on the biofilm, organic pollutants in the sewage are removed and the sewage is purified.

[0031] Nitrification is mainly accomplished through the metabolism of aerobic autotrophic microorganisms living in the nitrifying biofilter.

[0032] Ammonia nitrogen is oxidized in two steps by aerobic autotrophic microorganisms.

[0033] Nitrite bacteria: 2NH4+3O2→2NO2 - +2H2O+4H + Nitrobacter: 2NO2+O2→2NO3 - The whole reaction: NH4+2O→NO - +H2O+2H + By oxidizing the substrate (ie pollutants in the wastewater) with the help of specialized enzymes, the microorganisms obtain the energy they need for their metabolism to form new cells.

[0034] Furthermore, on the basis of the traditional aerated biological filter, combined with the contact oxidation process, a new type of high-efficiency environmentally friendly material filler is applied. The new filler has a high filling density and a large specific surface area. The filler can improve the mass transfer efficiency, maintain the activity of the biofilm, and greatly improve the pollutant removal rate. At the same time, this filler has a good interception effect on suspended matter in the water, increases the residence time of suspended sludge in the system, and the detached biofilm gradually decomposes in the system, reducing the effluent SS and greatly reducing the sludge production.

[0035] This filler enhances the removal efficiency of pollutants by the biochemical system, effectively resists shock loads, and ensures that the effluent quality is stable and up to standard. Its biggest feature is that it integrates biological action and interception of suspended solids, which simplifies the treatment process while ensuring the treatment effect. In addition, CAF has the characteristics of large biomass and high oxygen utilization. The performance of the new filler is much higher than other fillers on the market. It has rich types of attached biofilms, low sludge production, and very high removal efficiency for COD and ammonia nitrogen.

[0036] Design parameters of biochemical equipment II: Hypoxic period residence time: 0.5h Aerobic residence time: 2.5h Nitrification volume load: 0.16kgNH3-N / m 3 ·d COD volume load: 0.80kgCOD / m 3 ·d Filler: Biochemical filler 4.2m; Gas-water ratio: 6:1.

[0037] See the schematic diagram of the magnetic precipitation equipment for Figure 5 Based on the heavy medium loading sedimentation technology, the conventional flocculation sedimentation method is used to increase the settling rate of flocs by adding high-efficiency and recyclable magnetic powder in the coagulation stage, and assisted by a sludge return device to improve the coagulation reaction effect.

[0038] Since the specific gravity of magnetic powder is relatively large, it can effectively combine with flocs during the flocculation reaction, making the flocs larger and denser, effectively increasing the specific gravity of the flocs, and can settle at a high speed in the clarifier, thereby effectively improving the treatment efficiency of the clarifier.

[0039] Its main features are as follows: 1) Using magnetic seeds as floc carriers has a good reaction effect.

[0040] 2) It has good removal effect on SS and TP, and also has certain removal effect on insoluble COD.

[0041] 3) Strong impact load resistance, up to 35m 3 / (m 2 •h).

[0042] 4) The process occupies less space and has large processing capacity.

[0043] 5) Low operating cost and long equipment life.

[0044] This embodiment is also provided with a dosing and dehydration room, a fan room and a power distribution room, a reagent stacking room, an online monitoring room, etc.; all of them are existing technologies and will not be described in detail.

[0045] The integrated sewage treatment system and method for separate nitrogen removal and phosphorus removal of the present invention was used to treat the temporary integrated sewage treatment service project of Huangmaling drainage channel in Dalang Town. The water inlet detection results are as follows:

[0046] The water quality of the outlet is tested as follows:

[0047] From the above, it can be seen that the integrated sewage treatment system and method for separate denitrification and phosphorus removal of the present invention can simultaneously perform denitrification and phosphorus removal.

[0048] The treatment system and method of the present invention are used in the company's Dalang Town Huangmaling drainage canal temporary integrated sewage treatment service project. The data for one month of operation are as follows: the highest inlet COD is 369.89 mg / L, the effluent COD is 8.66 mg / L, the highest inlet ammonia nitrogen is 40.42 mg / L, the effluent ammonia nitrogen is 0.03 mg / L, the highest inlet total phosphorus is 5.25 mg / L, and the effluent total phosphorus is 0.18 mg / L.

[0049] The data of one month of operation is shown in the table below.

[0050] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An integrated sewage treatment system with separate nitrogen removal and phosphorus removal, characterized by: It includes a grille and a water collection tank, a biochemical device 1, a biochemical device 2, a magnetic precipitation device, a sludge dewatering room, and a sludge storage tank; the biochemical device 1 is an A / O process denitrification device, the biochemical device 2 is an A / O process biofilm denitrification device, and the magnetic precipitation device is a flocculation precipitation method magnetic precipitation device; sewage flows into the grille and the water collection tank, and then flows into the biochemical device 1, the biochemical device 2, and the magnetic precipitation device in turn for treatment, the water that meets the purification standard flows out of the magnetic precipitation device, and the sludge flows from the magnetic precipitation device in turn to the sludge dewatering room and the sludge storage tank and is transported out; The biochemical equipment 1 includes an anoxic zone and an aerobic zone, the biochemical equipment 2 includes an anoxic zone and an aerobic zone, and the magnetic precipitation equipment includes a coagulation device and a sedimentation tank; sewage enters in stages, part of the water enters the anoxic zone of the biochemical equipment 1, and the rest of the water enters the anoxic zone of the biochemical equipment 2; there is no sewage return equipment between the biochemical equipment 1 and the biochemical equipment 2, and the nitrification liquid of the biochemical equipment 1 completely enters the anoxic section of the biochemical equipment 2 for denitrification.

2. The integrated sewage treatment system for nitrogen removal and phosphorus removal according to claim 1 is characterized in that: The sedimentation tank of the magnetic sedimentation equipment is provided with a sludge return pipe, and the sludge that needs to be repeatedly treated flows back to the coagulation device for magnetic sedimentation treatment; it is also provided with a filtrate tank and a sludge tank, and the waste liquid generated by dehydration in the sludge dehydration room flows to the filtrate tank for filtration, the sludge sediments into the sludge tank, and the filtered waste liquid flows to the collection tank.

3. The integrated sewage treatment system for nitrogen removal and phosphorus removal according to claim 1 is characterized in that: The anoxic zone of the biochemical equipment 1 includes a water inlet 1, a water inlet 2, and a pretreatment component; the aerobic zone includes a three-phase separator, a three-phase separator bracket, an overflow weir, an overflow weir bracket, an air outlet pipe 1, a water outlet trough 1, a water outlet pipe 1, an aeration system 1, and an aeration system 2; it also includes a water guide pipe, through which water is guided between the anoxic zone and the aerobic zone; it also includes a perforated mud discharge pipe.

4. The integrated sewage treatment system for nitrogen removal and phosphorus removal according to claim 1 is characterized in that: The anoxic zone of the biochemical equipment 2 includes water inlet 3, water inlet 4, and a water distribution trough, and the aerobic zone includes a buoy, baffle 1, baffle 2, baffle 3, water outlet trough 2, water outlet 2, baffle support columns, and aeration system 3; both the anoxic zone and the aerobic zone are provided with special-shaped fillers, combined fillers and filler frames.

5. The integrated sewage treatment system for nitrogen removal and phosphorus removal according to claim 1 is characterized in that: The magnetic sedimentation equipment includes a water inlet weir, a rapid mixing reaction tank, a magnetic medium mixing reaction tank, a flocculation reaction tank, a magnetic mud sedimentation tank, a residual magnetic mud pump, a reflux magnetic mud pump, and a magnetic recovery machine; the water to be treated enters the rapid mixing reaction tank, the magnetic medium mixing reaction tank, the flocculation reaction tank in sequence, and then enters the sedimentation tank, and is discharged from the sump at the top of the sedimentation tank after treatment; part of the magnetic mud in the bottom sludge area is returned to the magnetic medium coagulation reaction tank through the reflux magnetic mud pump, and the remaining part enters the magnetic recovery machine.

6. An integrated sewage treatment method for separate nitrogen removal and phosphorus removal comprises the following steps: S1, after the sewage from the municipal pipe network is separated by coarse, medium and fine screens to remove coarse and fine floating objects, it is lifted to the biochemical equipment through the lifting pump of the water collection tank; the screen residue separated by the screen is cleaned regularly by the operating personnel; S2, the interior of the biochemical equipment is divided into two levels of A / O, and the sewage enters the anoxic zone and aerobic zone in the biological pool in multiple stages, so that the carbon source in the sewage can be selectively supplied to different functional areas. The nitrification liquid of the biochemical equipment 1 enters the anoxic zone of the biochemical equipment 2 to achieve denitrification and denitrification, and nitrification is achieved again in the aerobic zone to remove the remaining ammonia nitrogen; S3, the wastewater after biochemical treatment enters the rapid mixing tank of the magnetic precipitation equipment, where coagulant, magnetic powder and PAM are added, and solid-liquid separation is performed after precipitation to remove SS and total phosphorus; S4, the remaining sludge from the high-efficiency sedimentation equipment is pumped to the high-efficiency cutting machine by a cutting pump. After the magnetic powder is recovered, the remaining sludge flows to the sludge pool by gravity, and is pumped to the screw stacking dehydrator for mechanical dehydration by a screw pump. It is further concentrated and dehydrated by adding PAM (cationic). After dehydration, the sludge moisture content reaches about 85% and is then transferred to the sludge storage tank for regular external disposal.

7. The integrated sewage treatment method for separate nitrogen removal and phosphorus removal according to claim 6 is characterized in that: The step S3 further comprises: S31, the water to be treated is pumped to the coagulation system, first enters the rapid mixing reaction tank, adds coagulant in a certain proportion, and is fully mixed, then flows into the magnetic medium mixing reaction tank by gravity, adds magnetic medium and reflux magnetic mud, and is stirred at a uniform speed by a stirrer to form small flocs, and then enters the flocculation reaction tank, and then adds coagulant in a certain proportion, and after being evenly mixed, forms dense flocs wrapped around the magnetic medium; S32, the dense flocs wrapped with magnetic media enter the sedimentation tank and quickly settle to the sludge area at the bottom of the tank under the action of gravity. The tiny flocs that are not easy to settle are captured by the inclined tube, and finally high-quality clean water is discharged from the overflow of the sump at the top of the sedimentation tank. Part of the magnetic mud in the bottom sludge area is returned to the magnetic medium coagulation reaction tank through the magnetic mud pump, and the rest enters the magnetic medium recovery system; S33, the remaining magnetic mud is first dispersed into magnetic medium and residual mud residue by the deflocculant, and the magnetic medium is recovered by the magnetic recovery machine to the magnetic medium mixing reaction tank for recycling, and the remaining mud residue enters the sludge dewatering treatment system.

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