Sewage treatment system and treatment method

Abstract

The invention discloses a sewage treatment system and a treatment method.The sewage treatment system comprises a coagulating sedimentation module, a phosphorus recovery module, an anoxic and aerobic treatment module and a PN / A treatment module, the phosphorus recovery module is connected with the coagulating sedimentation module and used for receiving settled sludge of the coagulating sedimentation module and recovering phosphorus elements; the anoxic and aerobic treatment module comprises an anoxic tank, an aerobic tank and a secondary sedimentation tank which are connected in sequence, and the anoxic tank is connected with the coagulating sedimentation module; the PN / A treatment module comprises a reaction module, the reaction module is connected with the secondary sedimentation tank, and the reaction module is filled with a carrier filler; the carrier filler comprises a K3 filler and a polyurethane filler, and is at least used for loading short-cut nitrifying bacteria and anaerobic ammonium oxidation bacteria. Wherein the anoxic and aerobic treatment module is arranged, so that the energy consumption of the system can be reduced, and the sewage treatment stability is improved; k3 filler and polyurethane filler are matched in the PN / A treatment module, so that quick biofilm formation in the early stage of sewage treatment can be facilitated, a biofilm is stable in the later stage, and the treatment efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a sewage treatment system and a treatment method. Background Art

[0002] The excessive discharge of nutrients such as nitrogen and phosphorus in sewage can lead to eutrophication, which has a serious impact on the water body ecosystem. In order to effectively control water body eutrophication, extensive research has been carried out on the removal of nitrogen and phosphorus in urban sewage, aquaculture wastewater and industrial wastewater at home and abroad, and a variety of technical processes have been formed.

[0003] Although conventional biological nitrogen and phosphorus removal processes (such as A / O process, A / A / O process, SBR, etc.) can achieve certain treatment effects in actual operation, they often have problems such as high aeration energy consumption, large sludge production, and easy fluctuation of treatment efficiency. Especially for the treatment of high ammonia nitrogen and high organic load wastewater, the investment and operation costs of conventional processes are often high, and it is difficult to achieve up-to-standard discharge efficiently, stably and with low energy consumption.

[0004] In recent years, in the field of high ammonia nitrogen wastewater treatment, the emergence of anaerobic ammonium oxidation (Anammox) technology has greatly promoted the energy conservation and emission reduction process of high ammonia nitrogen wastewater. However, the pure Anammox process has relatively strict requirements for influent conditions, start-up environment and operating conditions, and it is often difficult to be directly applied to actual industrial wastewater or municipal sewage.

[0005] To overcome the above limitations, the partial nitrification-anaerobic ammonium oxidation (PN / A) process has emerged. Through partial nitrification, ammonia nitrogen is oxidized to nitrite nitrogen, and then the remaining ammonia nitrogen and nitrite nitrogen are converted into nitrogen gas by anaerobic ammonium oxidizing bacteria, thus significantly reducing the demand for carbon source, oxygen and sludge production, and having obvious economic and environmental advantages in the process of nitrogen removal. Further, an integrated PN / A process has also emerged at present. Specifically, partial nitrification and anaerobic ammonium oxidation reactions are carried out simultaneously in a single reactor, and the denitrification treatment of sewage is achieved through the combined action of partial nitrifying bacteria such as ammonia oxidizing bacteria (AOB) and anaerobic ammonium oxidizing bacteria (AnAOB), which can significantly improve the treatment efficiency.

[0006] In some current integrated treatment technologies, the upflow anaerobic sludge bed (UASB) carrier-free mode is often used to place partial nitrifying bacteria (aerobic and oxygen-requiring) and anaerobic ammonium oxidizing bacteria (absolutely anaerobic) in the same completely mixed environment. However, the oxygen content requirements of the two types of bacteria are completely different, and it is usually difficult to simultaneously meet the growth conditions of both in a single reactor. The fillers used usually cannot take into account both the film hanging speed and the stability of the biofilm, resulting in low treatment efficiency. Summary of the Invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a sewage treatment system and a treatment method.

[0008] In a first aspect of the present invention, a sewage treatment system is provided, comprising:

[0009] A coagulation sedimentation module configured to at least perform coagulation sedimentation treatment on sewage to form sediment sludge and supernatant;

[0010] A phosphorus recovery module connected to the coagulation sedimentation module and configured to receive the sediment sludge from the coagulation sedimentation module and perform phosphorus recovery treatment;

[0011] An anoxic-aerobic treatment module, which includes an anoxic tank, an aerobic tank and a secondary sedimentation tank connected in sequence. The anoxic tank is connected to the coagulation sedimentation module and is configured to receive the supernatant from the coagulation sedimentation module and perform anoxic treatment;

[0012] A shortcut nitrification-anaerobic ammonium oxidation treatment module, including a reaction module connected to the secondary sedimentation tank; the reaction module is filled with carrier fillers, and the carrier fillers include K3 fillers and polyurethane fillers and are configured to at least carry shortcut nitrifying bacteria and anaerobic ammonium oxidizing bacteria.

[0013] According to the sewage treatment system of the embodiments of the present invention, it has at least the following beneficial effects: The sewage treatment system includes a coagulation sedimentation module, a phosphorus recovery module, an anoxic-aerobic treatment module, and a shortcut nitrification-anaerobic ammonium oxidation treatment module. Among them, the coagulation sedimentation module can be used to remove phosphorus elements and solid particle impurities in the sewage, thereby reducing the burden on subsequent biological units (including the shortcut nitrification-anaerobic ammonium oxidation treatment module) and reducing the risk of sludge bulking; the phosphorus recovery module can achieve efficient recovery and high-value utilization of phosphorus resources, improving economic benefits; the anoxic-aerobic treatment module can be used to sequentially perform anoxic treatment, aerobic treatment, and sludge-water separation treatment on the effluent of the coagulation sedimentation module, which can reduce the oxygen consumption in the shortcut nitrification process in the shortcut nitrification-anaerobic ammonium oxidation treatment module, reduce the system energy consumption, and is more conducive to controlling the aeration volume and the type of dominant bacteria, improving the stability of sewage treatment. Especially when the influent COD concentration or nitrate nitrogen content of the anoxic-aerobic treatment module is relatively high, if the sewage directly enters the shortcut nitrification-anaerobic ammonium oxidation treatment module for treatment after passing through the coagulation sedimentation module, the oxygen consumption in the shortcut nitrification process will increase, which will further increase the system energy consumption, and the aeration volume is difficult to control, and it is impossible to accurately control the shortcut nitrifying bacteria as the dominant bacteria, which will cause excessive nitrate nitrogen to be produced in the effluent of the shortcut nitrification, resulting in poor anaerobic ammonium oxidation reaction. However, the sewage treatment system of the present invention can effectively overcome the above problems by setting an anoxic-aerobic treatment module between the coagulation sedimentation module and the shortcut nitrification-anaerobic ammonium oxidation treatment module, and the advantages are obvious. Moreover, the anoxic tank in the anoxic-aerobic treatment module can utilize the nitrate nitrogen carried by the influent to consume organic matter, realize partial denitrification, and reduce the organic load of the aerobic tank; the aerobic tank can oxidize and remove the remaining part of the organic matter in an environment with sufficient dissolved oxygen, and at the same time complete partial nitrification, providing appropriate ammonia nitrogen conversion or nitrite nitrogen conditions for the reaction module of the subsequent shortcut nitrification-anaerobic ammonium oxidation treatment module, thereby improving the treatment efficiency.

[0014] The reaction module of the shortcut nitrification-anaerobic ammonium oxidation treatment module is filled with carrier fillers including K3 fillers and polyurethane fillers, which can be used to load microorganisms including shortcut nitrifying bacteria and anaerobic ammonium oxidizing bacteria. The K3 fillers and polyurethane fillers cooperate to provide a diverse and high specific surface area immobilization environment for the microorganisms. In particular, the polyurethane fillers have unique porous sponge characteristics, which can enable the microorganisms to enrich on the fillers faster, and at the same time form an internal anaerobic environment for the enrichment of anaerobic ammonium oxidizing bacteria, while an external aerobic environment for the enrichment of shortcut nitrifying bacteria. When mass transfer occurs, water passes through the outside and undergoes shortcut nitrification reaction under the action of shortcut nitrifying bacteria, converting part of the ammonia nitrogen into nitrite nitrogen, and then carrying ammonia nitrogen and nitrite nitrogen into the interior of the fillers, where anaerobic ammonium oxidation reaction occurs under the action of anaerobic ammonium oxidizing bacteria, converting ammonia nitrogen and nitrite nitrogen into nitrogen. Thus, the shortcut nitrifying bacteria and anaerobic ammonium oxidizing bacteria can effectively cooperate, improving the system stability, reducing the aeration demand and significantly reducing the sludge yield. The polyurethane sponge fillers have a fast film-forming speed and can be rapidly enriched in the short term. However, dead zones are likely to occur during long-term use. The K3 fillers have a slow film-forming speed, but the biofilm is stable and dead zones are not easily formed. The combination of the two is conducive to ensuring rapid film formation in the early stage and stable biofilm in the later stage, improving the treatment efficiency.

[0015] During the research process, the inventors conducted in-depth research on the carrier fillers used to load shortcut nitrifying bacteria and anaerobic ammonium oxidizing bacteria in the shortcut nitrification-anaerobic ammonium oxidation treatment module, including conducting research experiments with other different carrier fillers, and found that there are different problems with other carrier fillers. For example, if only K3 fillers, PP hollow ball fillers or a combination of the two are used to load shortcut nitrifying bacteria and anaerobic ammonium oxidizing bacteria, there are problems with difficult film formation and it is difficult to form an internal and external wrapped and layered environment; the biological rope fillers are more likely to catch substances such as fibers that may exist in the influent water and are difficult to maintain. Therefore, the present invention selects to use carrier fillers including K3 fillers and polyurethane fillers. Further, in some embodiments, the carrier fillers are only composed of K3 fillers and polyurethane fillers.

[0016] In some embodiments of the present invention, in the carrier fillers, the mass ratio of the K3 fillers to the polyurethane fillers is (0.5-2):1. For example, the mass ratio of the K3 fillers to the polyurethane fillers can be any one of 0.5:1, 0.6:1, 0.65:1, 0.7:1, 0.8:1, 0.85:1, 0.9:1, 1:1, 1.2:1, 1.25:1, 1.4:1, 1.5:1, 1.65:1, 1.7:1, 1.8:1, 2:1 or any range value between any two of them. By controlling the mass ratio of the K3 fillers and polyurethane fillers within the above range, it can effectively ensure rapid film formation in the early stage and stable biofilm in the later stage.

[0017] In some embodiments of the present invention, the filling rate of the carrier filler in the reaction module is 50% to 75%. For example, the filling rate of the carrier filler in the reaction module can be any value among 50%, 52%, 55%, 58%, 60%, 62%, 64%, 65.5%, 67%, 70%, 71%, 72%, 73%, 75% or any range value between any two of them.

[0018] In some embodiments of the present invention, the carrier filler is loaded with short-cut nitrifying bacteria and anaerobic ammonium-oxidizing bacteria (AnAOB).

[0019] In some embodiments of the present invention, the short-cut nitrifying bacteria are ammonia-oxidizing bacteria (AOB).

[0020] In some embodiments of the present invention, the anoxic-aerobic treatment module further includes an aeration device, and the aeration device is configured to supply oxygen by aeration to the aerobic tank.

[0021] In some embodiments of the present invention, the anoxic-aerobic treatment module further includes a monitoring module and an aeration device. The monitoring module is configured to monitor the influent COD concentration and / or nitrate nitrogen content of the anoxic-aerobic treatment module; the aeration device is linked with the monitoring module and is configured to regulate the aeration volume to the aerobic tank according to the influent COD concentration and / or nitrate nitrogen content of the anoxic-aerobic treatment module.

[0022] In some embodiments of the present invention, in the anoxic-aerobic treatment module, a sludge reflux component is provided between the secondary sedimentation tank and the anoxic tank. Through the setting of the sludge reflux component, part of the sludge in the secondary sedimentation tank can be refluxed to the anoxic tank, enhancing the biomass of denitrifying bacteria and other facultative microorganisms in this section, forming an anoxic-aerobic cycle, thereby improving the treatment efficiency; while the excess sludge can be regularly discharged from the system and externally disposed of or further treated as needed.

[0023] The coagulation sedimentation module is configured to at least perform coagulation sedimentation treatment on sewage to form sediment sludge and supernatant. In some embodiments, the coagulation sedimentation module includes a coagulation sedimentation reactor, and the coagulation sedimentation reactor can be a coagulation sedimentation reaction tank, a coagulation sedimentation reaction barrel, etc. In the specific sewage treatment process, the sewage is first introduced into the coagulation sedimentation reactor. A coagulant including a phosphorus removal agent can be added into the coagulation sedimentation module to enable the phosphorus element in the sewage to react with the phosphorus removal agent to form a phosphorus-containing flocculant, and the phosphorus-containing flocculant and the large particle suspended matters originally contained in the sewage are removed. Then, the sludge including the phosphorus-containing flocculant and large particle solid impurities is introduced into the phosphorus recovery module for chemical phosphorus recovery treatment, and the obtained supernatant (i.e., the sewage treated in this section) is introduced into the anoxic-aerobic treatment module as pretreated sewage, which can improve the sewage treatment efficiency.

[0024] In some embodiments of the present invention, the coagulation sedimentation module further includes a phosphorus remover storage container, which is connected to the coagulation sedimentation reactor. Among them, the phosphorus remover storage container is configured to store the phosphorus remover and provide the phosphorus remover for the coagulation sedimentation reactor; the phosphorus remover can be an iron salt or other phosphorus removers. Through the above design, it is beneficial to achieve the precise dosing of the phosphorus remover and reduce the waste of chemicals.

[0025] In some embodiments of the present invention, the coagulation sedimentation module further includes a sand removal module, which is connected to the coagulation sedimentation reactor. The sand removal module has a water outlet and a sludge discharge port. The water outlet is connected to the anaerobic tank, and the sludge discharge port is connected to the phosphorus recovery module. Through the setting of the sand removal module, the efficiency of sewage phosphorus and sand removal can be improved, the subsequent sewage treatment burden can be effectively reduced, and the phosphorus recovery rate can be increased at the same time.

[0026] In some embodiments of the present invention, the sand removal module is selected from a hydrocyclone; further, the hydrocyclone can be a conical hydrocyclone or a cylindrical-conical hydrocyclone.

[0027] In some embodiments of the present invention, the phosphorus recovery module includes a sludge acidification reactor and a reaction sedimentation tank connected to each other; the sludge acidification reactor is connected to the coagulation sedimentation module and is configured to receive the sedimented sludge of the coagulation sedimentation module and perform anaerobic acidification fermentation treatment; the reaction sedimentation tank is configured to perform precipitation reaction and separation and recovery treatment on the phosphorus released from the sedimented sludge.

[0028] In some embodiments of the present invention, the phosphorus recovery module is an iron salt chemical phosphorus recovery reaction module, and the phosphorus remover used in the treatment process of the coagulation sedimentation module is an iron salt.

[0029] In the specific sewage treatment process, the sedimented sludge discharged from the coagulation sedimentation module enters the sludge acidification reactor of the phosphorus recovery module for anaerobic acidification fermentation treatment. The organic matter in the sedimented sludge is acidified and hydrolyzed into small molecule organic acids such as acetic acid and propionic acid, which can promote the system pH to about 4. Phosphorus is dissolved and released into the liquid phase under the action of acidification hydrolysis and biological dissimilatory iron reduction, and divalent iron ions are released simultaneously during the anaerobic acidification fermentation process; then it is introduced into the reaction sedimentation tank. Based on the theory of iron and phosphorus flocculation precipitation, the oxidation-reduction potential (ORP) in the sludge fermentation broth can be adjusted by adding oxidants such as hydrogen peroxide to the reaction sedimentation tank, oxidizing the divalent iron ions released by the sludge acidification fermentation into trivalent iron ions, and then adjusting the pH to acidic conditions to form iron phosphate precipitation through reaction, realizing efficient separation and recovery.

[0030] In some embodiments, the outlet of the reaction sedimentation tank can also be connected to the anoxic tank, so that the supernatant of the reaction sedimentation tank can be conveyed to the anoxic tank. Thus, the volatile fatty acids (VFAs) generated and accumulated during the sludge acidification fermentation process can be fully utilized as a supplementary carbon source in the denitrification stage of the anoxic tank unit of the sewage, reducing the operation cost of carbon source addition while increasing the sewage resource utilization benefit. Thereby, the efficient recovery and high-value utilization of carbon and phosphorus resources can be achieved simultaneously, with significant economic benefits.

[0031] In the short-cut nitrification-anaerobic ammonium oxidation treatment module, the reaction module is a short-cut nitrification-anaerobic ammonium oxidation reaction module, and the sewage to be treated can achieve nitrogen removal through short-cut nitrification reaction and anaerobic ammonium oxidation reaction in this reaction module. Further, the reaction module is an integrated short-cut nitrification-anaerobic ammonium oxidation reaction module. When treating sewage, short-cut nitrifying bacteria and anaerobic ammonium oxidizing bacteria are loaded on the carrier packing in the reaction module. Under a low dissolved oxygen (or anoxic) environment, the short-cut nitrifying bacteria partially oxidize ammonia oxygen to nitrite nitrogen, and the anaerobic ammonium oxidizing bacteria couple and convert nitrite nitrogen and the remaining ammonia nitrogen into nitrogen gas. Thus, to maintain the "anoxic" state rather than the "fully aerobic" state during the short-cut nitrification reaction process, only a small amount of air needs to be added to the reaction module to ensure the survival conditions of both short-cut nitrifying bacteria and anaerobic ammonium oxidizing bacteria, thereby significantly reducing the oxygen demand and at the same time reducing the demand for external carbon sources.

[0032] In some embodiments of the present invention, the reaction module includes at least one reaction unit, and the reaction unit includes a reaction tank and a rotary cage reactor. The rotary cage reactor is arranged in the reaction tank, and the carrier packing is filled in the rotary cage reactor. During the treatment process, the sewage can enter the reaction tank and contact the carrier packing loaded with short-cut nitrifying bacteria and anaerobic ammonium oxidizing bacteria through the rotary cage reactor. Then, under the action of the short-cut nitrifying bacteria and anaerobic ammonium oxidizing bacteria, short-cut nitrification reaction and anaerobic ammonium oxidation reaction occur. By constructing the reaction module by setting a rotary cage reactor in the reaction tank as above, the system can have stronger controllability for sewage treatment, improve the bacterial amount and the stability of the biofilm (or the stability of microbial loading), and by controlling the rotation of the rotary cage reactor, the carrier packing can be evenly contacted with the sewage, and the blockage caused by excessive growth of the biofilm can be reduced, thereby improving the efficiency and stability of sewage treatment.

[0033] In some embodiments of the present invention, the rotary cage reactor is a vertical rotary cage reactor. Further, the vertical rotary cage reactor can be designed to include a rotating shaft, a rotary cage, and a partition plate; the rotary cage is arranged in the reaction tank through the rotating shaft and is configured to be rotatable along the rotating shaft; the partition plate is arranged in the rotary cage and divides the rotary cage into at least two zones along the radial direction of the rotary cage; the carrier packing is filled in each zone, and the carrier packing is separated and defined in each zone by the partition plate. Further, the rotary cage can be designed with a grid-shaped outer frame, and the particle size of the carrier packing is generally larger than the aperture of the outer frame of the rotary cage; if the partition plate also has through holes, the particle size of the carrier packing is generally also larger than the aperture of the partition plate.

[0034] By the combined addition of K3 packing and polyurethane packing, and the setting of the vertical rotary cage reactor, it is beneficial to realize the combined zoning attachment and co-growth of two types of functional bacteria, namely short-cut nitrifying bacteria and anaerobic ammonium-oxidizing bacteria, and can greatly improve the shock resistance ability.

[0035] In some embodiments of the present invention, the number of reaction units is 1.

[0036] In some embodiments of the present invention, the number of reaction units is two or more, and the reaction tanks of each reaction unit are connected in sequence. For example, the number of reaction units can be 2, 3, 4, etc.

[0037] In some embodiments of the present invention, the short-cut nitrification-anaerobic ammonium oxidation treatment module further includes at least one of a pre-adjustment module and a sedimentation tank;

[0038] The reaction module is connected to the secondary sedimentation tank through the pre-adjustment module, that is, the reaction module and the secondary sedimentation tank are indirectly connected through the pre-adjustment module;

[0039] The sedimentation tank is connected to the reaction module and is configured to perform sediment-water separation treatment on the effluent of the reaction module.

[0040] In some embodiments of the present invention, in the short-cut nitrification-anaerobic ammonium oxidation treatment module, a sewage reflux component can also be arranged between the sedimentation tank and the pre-adjustment module.

[0041] In some embodiments of the present invention, the pre-adjustment module is configured to adjust the influent volume entering the reaction module to control the full and effective reaction of sewage in the reaction module.

[0042] In some embodiments of the present invention, the sludge treatment system further includes at least one of a temperature control device, an air blower, and a deoxidation device;

[0043] The air blower is configured to supply oxygen to the reaction module at least; the deoxidation device is configured to deoxidize the reaction module at least.

[0044] The temperature control device is configured to control the temperature of the reaction module at least, so as to ensure the activities of the short-cut nitrifying bacteria and anaerobic ammonium-oxidizing bacteria during the sewage treatment process and ensure the denitrification efficiency; for example, the temperature control device can adopt heating devices such as electric heating tubes and heat exchangers to keep the sewage in the reaction module at a suitable growth temperature (such as 30°C - 35°C) for the short-cut nitrifying bacteria and anaerobic ammonium-oxidizing bacteria during the treatment process to ensure the activity of the bacterial community. In some embodiments, the temperature control device is further configured to control the temperature of the aerobic tank in the anoxic-aerobic module. Further, the temperature control device may further include a heat preservation device; the heat preservation device can be a heat preservation layer provided outside the reaction tank of the reaction module and / or outside the aerobic tank of the anoxic-aerobic module.

[0045] In some embodiments of the present invention, the air blower is further configured to supply oxygen to the aerobic tank; and / or, the deoxidation device is further configured to deoxidize the anoxic tank.

[0046] In some embodiments of the present invention, the deoxidation device includes an inert gas generating device and an inert gas blower; the inert gas generating device is configured to generate inert gas, the inert gas generating device is connected to the reaction module and / or the anoxic tank, and the inert gas blower is used to blow the inert gas generated by the inert gas generating device into the reaction module and / or the anoxic tank to control the dissolved oxygen content of the sewage therein. Among them, the inert gas generating device can be a nitrogen generating device, and the inert gas blower is correspondingly a nitrogen blower.

[0047] The PN / A process itself will inevitably produce a small amount of nitrate nitrogen. If there is no perfect subsequent unit for further treatment, the effluent may still not meet the standards stably. Therefore, in some embodiments of the present invention, the sewage treatment system further includes an aerated biological filter, and the aerated biological filter is connected to the short-cut nitrification-anaerobic ammonium oxidation treatment module. Through the setting of the aerated biological filter, the effluent of the short-cut nitrification-anaerobic ammonium oxidation treatment module is further deeply treated to remove the residual nitrate nitrogen and a small amount of suspended solids therein, ensure the stable discharge of the effluent up to the standard, and can improve the adaptability of the system to water quality fluctuations and the stable reliability of the system for sewage treatment.

[0048] The aerated biological filter is filled with filter materials. The filter materials can adopt granular filter materials or modular filter materials, and generally filter materials with high biological activity and large porosity are used. Further, the filter materials can specifically adopt sintered ceramics, volcanic rocks, synthetic biological ceramsite, etc.

[0049] In some embodiments of the present invention, the air blower is further configured to supply oxygen to the biological aerated filter.

[0050] In a second aspect of the present invention, a sewage treatment method is proposed, which is implemented by using any of the aforementioned sewage treatment systems of the present invention, and includes:

[0051] Pass the sewage into the coagulation sedimentation module for coagulation sedimentation treatment to form sediment sludge and supernatant;

[0052] Pass the sediment sludge into the phosphorus recovery module for chemical phosphorus recovery treatment;

[0053] Pass the supernatant into the anoxic-aerobic treatment module to perform anoxic treatment, aerobic treatment and sludge-water separation treatment in sequence;

[0054] Load short-cut nitrifying bacteria and anaerobic ammonium-oxidizing bacteria on the carrier packing in the reaction module of the short-cut nitrification-anaerobic ammonium oxidation treatment module; pass the sewage treated by the anoxic-aerobic treatment module into the short-cut nitrification-anaerobic ammonium oxidation treatment module, and perform short-cut nitrification reaction and anaerobic ammonium oxidation reaction in the reaction module.

[0055] In the above sewage treatment method, before the sewage enters the short-cut nitrification-anaerobic ammonium oxidation treatment module, it is first treated by the anoxic-aerobic treatment module. In this way, the oxygen consumption in the short-cut nitrification process in the short-cut nitrification-anaerobic ammonium oxidation treatment module can be reduced, the system energy consumption can be lowered, and it is easier to control the aeration volume and the type of dominant bacteria, improving the stability of sewage treatment, especially for the situation where the influent COD concentration and nitrate nitrogen content are too high; and the nitrate nitrogen carried by the influent can be used to consume part of the organic matter, and part of the ammonia nitrogen is converted into nitrite nitrogen, providing treatment conditions for the subsequent PN / A reactor, thereby improving the sewage treatment efficiency.

[0056] In some embodiments of the present invention, the coagulant used in the coagulation sedimentation treatment includes a phosphorus removal agent. In some embodiments, the phosphorus removal agent is an iron salt. Further, the iron salt can be at least one of ferric chloride and polyferric sulfate.

[0057] Specifically, the iron salt can be metered and added according to the influent flow ratio, and the addition amount can be adjusted according to the phosphorus concentration in the sewage. In some embodiments of the present invention, the addition amount of the iron salt can be in accordance with Fe 3+ and PO4 3- with a molar ratio of (1.5 - 2.5):1 for control. For example, the molar ratio of Fe 3+ and PO4 3- can be any value of 1.5:1, 1.6:1, 1.75:1, 1.8:1, 1.9:1, 2.0:1, 2.15:1, 2.2:1, 2.3:1, 2.5:1 or any range value between any two of them.

[0058] The coagulation sedimentation treatment time can be controlled within 5 min to 15 min, which can be specifically determined according to the water quality and the coagulation effect. For example, the reaction time can be controlled to any value among 5 min, 7 min, 8 min, 10 min, 12 min, 13 min, 15 min or the range value of any two of them. The coagulation sedimentation treatment process can be assisted by stirring and mixing, and the stirring rate only needs to maintain uniform mixing.

[0059] If the influent pH of the coagulation sedimentation module is too low (such as less than 6.0) or too high (such as greater than 9.0), appropriate adjustment is required to ensure the generation of stable iron-phosphorus flocs after the addition of iron salts. Furthermore, in some embodiments of the present invention, before the sewage is introduced into the coagulation sedimentation module for coagulation sedimentation treatment, the pH of the sewage is adjusted first, and specifically, the pH of the sewage can be adjusted and controlled within 6.5 to 8.5. For example, the pH value of the sewage can be controlled to any value among 6.5, 6.8, 7.0, 7.2, 7.5, 7.6, 7.8, 8.0, 8.2, 8.5 or the range value of any two of them.

[0060] After the coagulation sedimentation treatment, sand removal treatment can be carried out to remove large particle suspended solids and sand in the sewage, reducing or even avoiding the solid load of the subsequent system and the blockage or operation risks caused by excessive suspended solids or too large particles; at the same time, the flocs or precipitates generated by the coagulation sedimentation treatment can be removed, quickly and efficiently realizing the removal of phosphorus and sand from the sewage.

[0061] In some embodiments of the present invention, the influent flow rate can be controlled within 0.8 m / s to 1.2 m / s during the sand removal treatment process. For example, the influent flow rate can be any value among 0.8 m / s, 0.9 m / s, 0.95 m / s, 1.0 m / s, 1.1 m / s, 1.15 m / s, 1.2 m / s or the range value of any two of them. The sand removal treatment process can adopt regular or continuous discharge of sand.

[0062] The sedimentation sludge after coagulation sedimentation treatment or the sludge after sand removal treatment can enter the phosphorus recovery module for chemical phosphorus recovery treatment. In some embodiments, the sludge can be first subjected to anaerobic acidification fermentation treatment to dissolve and release phosphorus and iron ions in the sludge, and then an oxidant is added thereto to oxidize the divalent iron ions released during the anaerobic acidification fermentation treatment into trivalent iron ions, and then the pH of the system is adjusted to acidic to react to form iron phosphate precipitation, thereby realizing the efficient separation and recovery of phosphorus; specifically, the sludge can be first introduced into the sludge acidification reactor of the phosphorus recovery module in the sewage treatment system for anaerobic acidification fermentation treatment, and then introduced into the reaction sedimentation tank for sedimentation reaction and separation and recovery treatment. In some embodiments, the supernatant obtained from the reaction sedimentation tank can also be transported to the anoxic tank, so that the VFAs generated and accumulated during the sludge acidification fermentation process can be fully utilized as the supplementary carbon source in the denitrification stage of the anoxic tank unit of the sewage, thereby reducing the operating cost of carbon source addition while increasing the sewage resource utilization benefit, so as to simultaneously realize the efficient recovery and high-value utilization of carbon and phosphorus resources.

[0063] In some embodiments of the present invention, the dissolved oxygen concentration of the sewage in the anoxic tank during the anoxic treatment process can be controlled to be 0.2 mg / L to 0.5 mg / L to ensure an anoxic environment. For example, the dissolved oxygen concentration can be any value of 0.2 mg / L, 0.25 mg / L, 0.3 mg / L, 0.4 mg / L, 0.45 mg / L, 0.5 mg / L or the range value of any two of them.

[0064] In some embodiments of the present invention, the hydraulic retention time (HRT) in the anoxic tank during the anoxic treatment process can be controlled to be 1 h to 2 h. For example, the HRT can be any value of 1 h, 1.2 h, 1.5 h, 1.6 h, 1.8 h, 2 h or the range value of any two of them, and can be appropriately adjusted according to the influent organic matter concentration and nitrate nitrogen content.

[0065] In some embodiments of the present invention, the dissolved oxygen concentration of the sewage in the aerobic tank during the aerobic treatment process can be controlled to be 1.5 mg / L to 2.5 mg / L. For example, the dissolved oxygen concentration can be any value of 1.5 mg / L, 1.65 mg / L, 1.7 mg / L, 1.8 mg / L, 2 mg / L, 2.15 mg / L, 2.2 mg / L, 2.35 mg / L, 2.4 mg / L, 2.5 mg / L or the range value of any two of them.

[0066] In some embodiments of the present invention, the HRT in the aerobic tank during the aerobic treatment process can be controlled to be 2 h to 4 h. For example, the HRT can be any value of 2 h, 2.5 h, 3 h, 3.5 h, 4 h or the range value of any two of them, and can be determined according to the influent water quality and treatment scale.

[0067] In addition, if the influent water temperature of the aerobic tank in the aerobic treatment process is too low (such as less than 15 °C), aeration can be appropriately strengthened or a temperature control device can be started to maintain the activity of nitrifying bacteria.

[0068] In some embodiments of the present invention, a part of the sludge generated by the sludge-water separation treatment in the secondary sedimentation tank of the anoxic-aerobic treatment module is refluxed to the anoxic tank to enhance the biomass of denitrifying bacteria and other facultative anaerobic microorganisms in the anaerobic section, forming an anoxic-aerobic cycle; the excess sludge can be regularly discharged from the system and externally disposed of or further treated as required.

[0069] When the sewage treated by the anoxic-aerobic treatment module is introduced into the reaction module for treatment, only a very small amount of air needs to be added to the reaction module. Specifically, the dissolved oxygen (DO) concentration in the system of the reaction module can be controlled to be 0.3 mg / L to 0.6 mg / L. For example, the dissolved oxygen concentration can be any value among 0.3 mg / L, 0.35 mg / L, 0.38 mg / L, 0.4 mg / L, 0.46 mg / L, 0.5 mg / L, 0.55 mg / L, 0.6 mg / L or the range value of any two of them, so as to maintain the "anoxic" state rather than the "fully aerobic" state in the reaction module, ensuring that the survival conditions of short-cut nitrifying bacteria and anaerobic ammonium oxidation bacteria are taken into account.

[0070] In some embodiments of the present invention, the hydraulic retention time in the reaction module during the treatment process can be controlled to be 2 h to 4 h. For example, the hydraulic retention time can be any value among 2 h, 2.5 h, 3 h, 3.5 h, 4 h or the range value of any two of them, and can be specifically adjusted according to the influent ammonia nitrogen concentration and flow rate.

[0071] Among them, the suitable temperature for the anaerobic ammonium oxidation reaction is generally 30 °C to 35 °C. Furthermore, the temperature of the system in the reaction module during the treatment process of the reaction module can be 30 °C to 35 °C. For example, the temperature can be controlled to be any value among 30 °C, 32 °C, 33 °C, 35 °C or the range value of any two of them. If the water temperature is on the low side, a temperature control device can be appropriately used for adjustment. In addition, the pH value of the sewage in the reaction module can be controlled within the range of 7.0 to 8.0. For example, the sewage pH value can be controlled to be any value among 7.0, 7.2, 7.3, 7.5, 7.6, 7.8, 8.0 or the range value of any two of them.

[0072] In some embodiments of the present invention, the reaction module includes a rotary cage reactor. During the sewage treatment process, the rotary cage reactor generally rotates at a low speed. Specifically, the rotation speed of the rotary cage reactor can be controlled to be 1 rpm to 5 rpm. For example, its rotation speed can be any value among 1 rpm, 1.5 rpm, 2 rpm, 2.5 rpm, 3 rpm, 4 rpm, 4.5 rpm, 5 rpm or the range value of any two of them, so as to avoid excessive scouring of the microbial membrane.

[0073] In some embodiments of the present invention, the sewage treatment method uses any one of the aforementioned sewage treatment systems of the present invention that includes an aerated biological filter; and the sewage treatment method further includes: introducing the sewage treated by the short-cut nitrification-anaerobic ammonium oxidation treatment module into the aerated biological filter for biochemical treatment. In this way, to further remove nitrate nitrogen, suspended solids, microbial metabolites, etc. in the sewage, so that the effluent meets or even exceeds the corresponding discharge standards and can be directly discharged or reused.

[0074] During the biochemical treatment process, the dissolved oxygen concentration of the sewage in the aerated biological filter can be controlled at 1 mg / L to 2 mg / L. For example, the dissolved oxygen concentration can be any value among 1 mg / L, 1.2 mg / L, 1.35 mg / L, 1.4 mg / L, 1.5 mg / L, 1.65 mg / L, 1.8 mg / L, 2 mg / L or the range value of any two of them, which is specifically achieved by maintaining mild aeration or intermittent aeration. In addition, the filtration rate of the aerated biological filter can be controlled at 4 m / h to 10 m / h. For example, the filtration rate can be any value among 4 m / h, 4.5 m / h, 5 m / h, 6 m / h, 6.5 m / h, 7 m / h, 8 m / h, 8.5 m / h, 9 m / h, 10 m / h or the range value of any two of them, and can be specifically adjusted according to the treatment scale and target effluent index. And the filter bed can be backwashed regularly to remove the accumulated aged biological film layer and solid deposits to maintain the long-term stability of the filtration function. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] The following further describes the present invention with reference to the drawings and embodiments, where:

[0076] Figure 1 is a schematic structural diagram of an embodiment of the sewage treatment system of the present invention;

[0077] Figure 2 is Figure 1 a schematic flow diagram of the sewage treatment system shown;

[0078] Figure 3 is Figure 1 a schematic structural diagram of the vertical rotating cage reactor in the sewage treatment system shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0079] The following will clearly and completely describe the concept and technical effects generated by the present invention in combination with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0080] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as a limitation of the present invention.

[0081] In the description of the present invention, it should be understood that for the orientation descriptions, such as upper, lower, front, rear, left, right, etc., the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0082] In the description of the present invention, the meaning of "several" is more than one, the meaning of "a plurality" is more than two, and understandings such as "greater than", "less than", "exceeding", etc. do not include the recited number, and understandings such as "above", "below", "within", etc. include the recited number. If there is a description of "first", "second", etc., it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0083] In the description of the present invention, unless otherwise clearly defined, words such as "set", "installed", "connected", etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0084] In the description of the present invention, the descriptions referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0085] Embodiment 1

[0086] This embodiment provides a sewage treatment system, as Figure 1 and Figure 2 shown. The sewage treatment system includes a coagulation sedimentation module, a phosphorus recovery module, an anoxic-aerobic treatment module, a shortcut nitrification-anaerobic ammonium oxidation treatment module, and a biological aerated filter.

[0087] Among them, the coagulation sedimentation module is configured to perform coagulation sedimentation treatment and sand removal treatment on sewage to form sediment sludge and supernatant, so as to remove phosphorus elements and solid particle impurities in the sewage, and the obtained supernatant is used as pretreated sewage and introduced into the anoxic-aerobic treatment module for treatment; the phosphorus recovery module is connected to the coagulation sedimentation module and is configured to receive the sediment sludge of the coagulation sedimentation module and perform phosphorus recovery treatment; the anoxic-aerobic treatment module is configured to perform anoxic treatment, aerobic treatment and sludge-water separation treatment on the effluent of the coagulation sedimentation module in sequence; the shortcut nitrification-anaerobic ammonium oxidation treatment module is configured to perform denitrification treatment on sewage; the biological aerated filter is configured to perform further advanced treatment on the effluent of the shortcut nitrification-anaerobic ammonium oxidation treatment module to remove residual nitrate nitrogen and a small amount of suspended solids.

[0088] The coagulation sedimentation module specifically includes a connected coagulation sedimentation reactor 11 and a sand removal module 12. In this embodiment, the coagulation sedimentation module further includes a phosphorus remover storage container 13, and the phosphorus remover storage container 13 is connected to the coagulation sedimentation reactor 11 for storing the phosphorus remover and supplying the phosphorus remover to the coagulation sedimentation reactor 11, and the coagulation sedimentation reactor 11 is connected to the sand removal module 12. Among them, a stirring device can be arranged in the phosphorus remover storage container 13 to prevent the phosphorus remover from precipitating during storage by stirring, and ensure that the phosphorus remover remains evenly distributed during storage; the coagulation sedimentation reactor 11 can adopt a coagulation sedimentation reaction tank, a coagulation sedimentation reaction barrel, etc., and can be supplemented with a stirring device to fully mix the phosphorus remover and the sewage during sewage treatment by stirring to improve the reaction efficiency. The sand removal module 12 is connected to the shortcut nitrification-anaerobic ammonium oxidation treatment module and the phosphorus recovery module (not shown in the figure). Specifically, the sand removal module 12 has a water outlet and a sludge discharge port. The water outlet of the sand removal module 12 is connected to the water inlet of the shortcut nitrification-anaerobic ammonium oxidation treatment module, and the sludge discharge port is connected to the phosphorus recovery module; the sand removal module 12 specifically adopts a hydrocyclone. During sewage treatment, the sewage is first introduced into the coagulation sedimentation reactor 11, and the phosphorus remover storage container 13 supplies the phosphorus remover into the coagulation sedimentation reactor 11 to enable the phosphorus elements in the sewage to react with the phosphorus remover to form phosphorus-containing flocs, and then introduced into the sand removal module 12. After removing the phosphorus-containing flocs and large particle solid impurities in the sewage, it enters the anoxic-aerobic treatment module, while the sludge including the phosphorus-containing flocs and solid impurities is introduced into the phosphorus recovery module for chemical phosphorus recovery treatment.

[0089] The phosphorus recovery module includes a connected sludge acidification reactor and a reaction sedimentation tank; the sludge acidification reactor is connected to the sludge discharge port of the sand removal module 12 and is configured to receive the sediment sludge discharged from the sand removal module and perform anaerobic acidification fermentation treatment; the reaction sedimentation tank is configured to perform precipitation reaction and separation recovery treatment on the phosphorus released in the sediment sludge.

[0090] The anoxic-aerobic treatment module includes an anoxic tank 21, an aerobic tank 22, and a secondary sedimentation tank 23 connected in sequence. The anoxic tank 21 is connected to the sand removal module 12, and the secondary sedimentation tank 23 is connected to the shortcut nitrification-anaerobic ammonium oxidation treatment module. There is a sludge return component (not shown in the figure) between the secondary sedimentation tank 23 and the anoxic tank 21. Specifically, the water inlet of the anoxic tank 21 is connected to the water outlet of the sand removal module 12, and the water outlet of the anoxic tank 21 is connected to the water inlet of the aerobic tank 22; the water outlet of the aerobic tank 22 is connected to the water inlet of the secondary sedimentation tank 23, and the water outlet of the secondary sedimentation tank 23 is connected to the water inlet of the shortcut nitrification-anaerobic ammonium oxidation treatment module. A stirring device 211 can be arranged in the anoxic tank 21 to enhance mass transfer, improve water quality uniformity, and accelerate the reaction. During the sewage treatment process, the effluent of the sand removal module 12 can be first passed through the anoxic tank 21, aerobic tank 22, and secondary sedimentation tank 23 of the anoxic-aerobic treatment module in sequence for anoxic treatment, aerobic treatment, and sludge-water separation treatment, and then the sewage separated by the secondary sedimentation tank 23 is introduced into the shortcut nitrification-anaerobic ammonium oxidation treatment module for treatment. Part of the sludge is refluxed to the anoxic tank 21 to enhance the biomass of denitrifying bacteria and other facultative microorganisms, and the excess sludge can be regularly discharged from the system.

[0091] In addition, the water outlet of the reaction sedimentation tank in the phosphorus recovery module is connected to the anoxic tank 21. Furthermore, the supernatant of the reaction sedimentation tank can be transported to the anoxic tank 21, so that the VFAs generated and accumulated during the sludge acidification fermentation process can be fully utilized as the supplementary carbon source in the denitrification stage of the anoxic tank unit of the sewage, reducing the operation cost of carbon source addition while increasing the sewage resource utilization benefit. Thus, while realizing the efficient recovery and utilization of phosphorus resources, the efficient recovery and high-value utilization of carbon resources can be achieved.

[0092] The anoxic-aerobic treatment module may further include a monitoring module and an aeration device. The monitoring module is configured to monitor the COD concentration and nitrate nitrogen content of the influent of the anoxic-aerobic treatment module (or the influent of the anoxic tank 21). The aeration device is used to supply oxygen to the aerobic tank 22. Specifically, the aeration device can be designed to be linked with the monitoring module and is configured to regulate the aeration volume to the aerobic tank 22 according to the COD concentration and / or nitrate nitrogen content of the influent of the anoxic-aerobic treatment module (or the influent of the anoxic tank 21). During the specific working process, when the monitoring module monitors that the COD concentration and / or nitrate nitrogen content of the influent of the anoxic-aerobic treatment module (or the influent of the anoxic tank 21) is too high, the aeration volume of the aeration device to the aerobic tank 22 can be increased; when the monitoring module monitors that the COD concentration and nitrate nitrogen concentration of the influent of the anoxic-aerobic treatment module (or the influent of the anoxic tank 21) are low, the aeration volume of the aeration device to the aerobic tank 22 can be reduced. In this way, while ensuring the treatment efficiency, the system energy consumption can be effectively reduced.

[0093] The short-cut nitrification-anaerobic ammonium oxidation treatment module includes a pre-regulation module 31, a reaction module 32 and a sedimentation tank 33 which are connected in sequence; the pre-regulation module 31 is connected to the secondary sedimentation tank 23, and the sedimentation tank 33 is connected to the aerated biological filter 40. Specifically, the water inlet of the pre-regulation module 31 is connected to the water outlet of the secondary sedimentation tank 23 in the anaerobic aerobic treatment module, the water outlet of the pre-regulation module 31 is connected to the water inlet of the reaction module 32, the water outlet of the reaction module 32 is connected to the water inlet of the sedimentation tank 33, and the water outlet of the sedimentation tank 33 is connected to the water inlet of the aerated biological filter 40.

[0094] In this embodiment, the reaction module 32 includes three reaction units, each reaction unit includes a reaction pool 321 and a cage reactor 322, the reaction pools 321 of each reaction unit are connected in sequence, and the cage reactor 322 is arranged in the reaction pool 321, specifically a vertical cage reactor, and its structure is as follows: Figure 3 As shown, it includes a rotating shaft 3221, a rotating cage 3222 and a partition plate 3223. The rotating cage reactor 322 is arranged in the reaction tank 321 through the rotating shaft 3221, and is configured so that the rotating cage 3222 can rotate along the rotating shaft 3221; the partition plate 3223 is arranged in the rotating cage 3222, and the rotating cage 3222 is divided into 4 partitions along the radial direction of the rotating cage 3222, and each partition is evenly filled with a carrier filler, and the carrier filler is used to load short-range nitrifying bacteria and anaerobic ammonia oxidizing bacteria. In this embodiment, the carrier filler is a K3 filler and a polyurethane filler mixed in a volume ratio of 1:1. The filling rate of the carrier filler in the rotating cage reactor 322 is about 30%, and the short-range nitrifying bacteria loaded on the carrier filler are ammonia oxidizing bacteria. The pre-regulating module 31 specifically adopts a pre-regulating tank.

[0095] A pre-regulating module 31 is provided before the reaction module 32 to regulate the water inflow into the reaction module. A sedimentation tank 33 is provided after the reaction module 32, and the sedimentation tank 33 is configured to perform mud-water separation treatment on the effluent of the reaction module 32. In addition, a sewage return component is also provided between the sedimentation tank 33 and the pre-regulating module 31.

[0096] The aerated biological filter 40 is connected to the short-cut nitrification-anaerobic ammonium oxidation treatment module. Specifically, the water inlet of the aerated biological filter 40 is connected to the water outlet of the sedimentation tank 33 in the short-cut nitrification-anaerobic ammonium oxidation treatment module. The aerated biological filter 40 is filled with filter material, which is sintered ceramsite with a particle size of 3mm to 5mm. The filter bed height in the aerated biological filter 40 is about 1.0m. Through the setting of the aerated biological filter 40, the effluent of the short-cut nitrification-anaerobic ammonium oxidation treatment module is further deeply treated to remove the residual nitrate nitrogen and a small amount of suspended solids therein, to ensure that the effluent is stably discharged up to standard, and to improve the system's adaptability to water quality fluctuations and the stability and reliability of the system's sewage treatment.

[0097] In addition, the sewage treatment system of this embodiment further includes a temperature control device (not shown in the figure), an air blower 50, and a deoxygenation device. Among them, the temperature control device includes an electric heating pipe and a heat preservation layer. The heat preservation layer is arranged outside the aerobic tank 22 and the reaction tank 321 of the reaction module 32. The electric heating pipe is configured to heat the sewage in the aerobic tank 22 and the reaction tank 321 during the sewage treatment process when the temperature of the sewage to be treated is lower than a predetermined lower limit temperature, so as to control the temperature within a predetermined temperature range; the air blower 50 is configured to supply oxygen to the reaction tank 321 and the biological aerated filter 40 in the short-cut nitrification-anaerobic ammonium oxidation treatment module in the anaerobic-aerobic treatment module during the sewage treatment process; and, in this embodiment, the aeration device of the anoxic-aerobic treatment module is the air blower 50, that is, the reaction tank 321 in the short-cut nitrification-anaerobic ammonium oxidation treatment module, the biological aerated filter 40, and the aerobic tank 22 in the anoxic-aerobic treatment module can share the same device for aeration and oxygen supply, thereby simplifying the system structure and saving the floor area for system layout. The deoxygenation device is configured to deoxygenate the reaction tank 321 in the short-cut nitrification-anaerobic ammonium oxidation treatment module during the sewage treatment process. The deoxygenation device specifically includes a nitrogen generation device 61 and a nitrogen blower 62. The nitrogen generation device 61 is connected to the reaction tank 321 of the reaction module 32, and the nitrogen blower 62 is used to send the nitrogen generated by the nitrogen generation device 61 to the reaction module 32 to control the dissolved oxygen content of the sewage therein.

[0098] When treating sewage with the above sewage treatment system, sewage can be introduced into the coagulation sedimentation reactor 11, and a phosphorus remover is supplied from the phosphorus remover storage container 13 into the coagulation sedimentation reactor 11 to mix and react with the sewage. Phosphorus elements in the sewage react with the phosphorus remover to form iron-phosphorus flocs. At the same time, some undegraded organic matters form organic floc precipitates after coagulation sedimentation. The reacted sewage is introduced into the sand removal module 12, and the sand removal module 12 removes sludge including iron-phosphorus flocs, other large particle suspended matters and sand in the sewage, and the sludge is introduced into the sludge acidification reactor of the phosphorus recovery module for anaerobic acidification fermentation treatment to release phosphorus and divalent iron ions in the sludge. Then, the fermentation broth is introduced into the reaction sedimentation tank, an oxidant is added thereto to oxidize divalent iron ions into trivalent iron ions, and a pH regulator is further added to adjust the pH of the system to acidic to form iron phosphate precipitates through reaction, and then separation and recovery are carried out. The supernatant of the reaction sedimentation tank can be transported to the anoxic tank 21 to supplement a carbon source for the anoxic tank. The effluent of the sand removal module 12 is introduced into the anoxic tank 21 of the anoxic-aerobic treatment module. In the anoxic tank 21, the sewage uses the nitrate nitrogen carried by the influent (or a part of the nitrate nitrogen carried by the returned sludge) to consume organic matters, realizing partial denitrification and reducing the organic load of the aerobic tank 22. The sewage treated in the anoxic tank 21 enters the aerobic tank 22, and under an environment with sufficient dissolved oxygen, the remaining part of the organic matters is oxidized and removed, and at the same time, partial nitrification is completed to provide appropriate ammonia nitrogen conversion or nitrate nitrogen conditions for subsequent shortcut nitrification-anaerobic ammonium oxidation treatment. The sewage treated in the aerobic tank 22 enters the secondary sedimentation tank 23 to complete the separation of mud and water. After the sludge in the mixed liquor is settled, part of it is refluxed to the anoxic tank 21, and the excess sludge is regularly discharged and externally treated or further treated as required. The separated sewage enters the pre-adjustment module 31 of the shortcut nitrification-anaerobic ammonium oxidation treatment module. The sewage introduced from the anoxic-aerobic treatment module is adjusted in quantity through the pre-adjustment module 31 and then sequentially enters the reaction tanks 321 of each reaction unit of the reaction module 32, and in each reaction tank 321, a shortcut nitrification and anaerobic ammonium oxidation integrated reaction is simultaneously carried out through the vertical rotary cage reactor 322 to remove ammonia nitrogen. The effluent of the reaction module 32 enters the sedimentation tank 33 to collect some suspended and un-filmed sludge in the sewage, and at least part of the sewage can be refluxed to the pre-adjustment module 31 according to the actual situation. The effluent of the sedimentation tank 33 enters the biological aerated filter 40 for further advanced treatment to remove the residual nitrate nitrogen and a small amount of suspended solids in the effluent of the shortcut nitrification-anaerobic ammonium oxidation treatment module to ensure stable discharge of the final effluent up to the standard.

[0099] The above sewage treatment system can effectively integrate and integrally integrate the sewage denitrification and phosphorus removal process links, achieving small footprint, low energy consumption, and integrated and efficient denitrification treatment; an anoxic-aerobic treatment module is arranged between the coagulation sedimentation module and the shortcut nitrification-anaerobic ammonium oxidation treatment module to sequentially perform anoxic treatment, aerobic treatment, and sludge-water separation treatment on the effluent of the coagulation sedimentation module, which can reduce the oxygen consumption in the shortcut nitrification process of the shortcut nitrification-anaerobic ammonium oxidation treatment module, reduce the system energy consumption, and is easier to control the aeration volume and the type of dominant bacteria, improving the stability of sewage treatment, especially for the situation where the influent COD concentration or nitrate nitrogen content is relatively high; through the combined addition of K3 filler and polyurethane filler, the synergistic stability of shortcut nitrification-anaerobic ammonium oxidation can be ensured, and at the same time, rapid film formation in the early stage and stable biofilm in the later stage can be ensured, improving the treatment efficiency; combined with the setting of the vertical rotating cage reactor and the reasonable rotational speed control during the cooperation process, the partition attachment and synergistic growth of two types of functional bacteria, namely shortcut nitrifying bacteria and anaerobic ammonium oxidizing bacteria, can be achieved, which can enhance the impact resistance ability during sewage treatment; making full use of the coupling of shortcut nitrification and anaerobic ammonium oxidation can significantly reduce the aeration volume and the demand for external carbon sources; by setting an aerated biological filter 40 at the end, the stable discharge of the system effluent can be ensured. Through the cooperation of each module, the overall treatment efficiency can be significantly improved, the sludge production can be reduced, and the energy consumption and operation cost can be reduced; moreover, the system has strong adaptability to water quality fluctuations. When the environmental or influent concentration changes, through operations such as temperature control device, adjusting the reflux ratio, and controlling the micro-aeration volume, the system stability can be maintained, and operation accidents such as sludge bulking or reaction imbalance are not likely to occur.

[0100] Example 2

[0101] This example proposes a sewage treatment method, which specifically uses the sewage treatment system shown in Example 1 for sewage treatment, and thus the treatment effect of the sewage treatment system in Example 1 can be verified.

[0102] Among them, the water quality of the raw sewage is as follows: the ammonia nitrogen content is 300 mg / L; the total phosphorus content (TP) is 15 mg / L; the COD is 1000 mg / L; the pH is 7.2 ± 0.2; the temperature is 25 ± 2 °C (under normal temperature and atmospheric pressure conditions, without additional pressurization or negative pressure).

[0103] The treatment process of this sewage treatment method is specifically as follows:

[0104] S1. Coagulation sedimentation and phosphorus recovery treatment, including: feeding the raw sewage into a coagulation sedimentation reactor and stirring and mixing it with a phosphorus remover. Among them, the usage concentration of the phosphorus remover is a 50 g / L ferric chloride solution, and the dosage is converted according to the influent phosphorus concentration, Fe 3+ and PO4 3-The molar ratio is 2:1, and the mixing reaction time can be controlled at 10 min. Phosphorus in the sewage reacts with ferric chloride to form iron-phosphorus flocs. At the same time, some undegraded organic matters form organic floc precipitates after coagulation sedimentation. In this process, more than 80% of phosphorus, 90% of iron, and 20% of organic matters accumulate in the sludge; the treated sewage is introduced into a hydrocyclone desander to remove the sludge including iron-phosphorus flocs, other large particulate suspensions, and sand deposits in the sewage, and the sludge is introduced into the sludge acidification reactor of the phosphorus recovery module for anaerobic acidification fermentation treatment. The organic matters in the sludge are acid-hydrolyzed into small-molecule organic acids such as acetic acid and propionic acid, which can promote the system pH to drop to about 4 in 3 - 5 days. Phosphorus is dissolved and released into the liquid phase under the action of acid hydrolysis and biological dissimilatory iron reduction, and divalent iron ions are released during the anaerobic acidification fermentation process of the sludge; then, based on the theory of iron and phosphorus flocculation precipitation, hydrogen peroxide is added to the system to adjust the redox potential (ORP) in the sludge fermentation broth, oxidize the divalent iron ions released by the sludge acidification fermentation into trivalent iron ions, and then adjust the pH to acidic conditions to form iron phosphate precipitates by reaction and then separate and recover them; the supernatant of the reaction sedimentation tank is introduced into an anoxic tank to fully utilize the VFAs generated and accumulated during the anaerobic acidification fermentation process of the sludge as the supplementary carbon source in the denitrification stage of the anoxic tank unit of the sewage; the effluent of the hydrocyclone desander is introduced into the anoxic-aerobic treatment module;

[0105] In the above treatment process, the main reactions in the coagulation sedimentation reactor are as follows:

[0106] Fe 3+ +PO4 3- +H2O→Fe(III)…P(s);

[0107] The main reaction process of the phosphorus recovery module is as follows:

[0108] FePO4+Fe(OH)3…P+CH2O→Fe3(PO4)2+Fe(OH)2…P+CO2+H2O;

[0109] Fe3(PO4)2+Fe(OH)2…P+H + →Fe 2+ +PO4 3- +H2O;

[0110] FeHPO4 + +nH2O→FePO4·nH2O+H + ;

[0111] FeH2PO4 2+ +nH2O→FePO4·nH2O+2H + .

[0112] S2. Anoxic-aerobic treatment, including: the effluent from the hydrocyclone sand remover first enters the anoxic tank of the anoxic-aerobic treatment module, and the hydraulic retention time (HRT) of the anoxic tank is controlled to be 1.5 h; the dissolved oxygen (DO) concentration is 0.3 - 0.5 mg / L. In the anoxic tank, the sewage uses the VFAs generated and accumulated during the anaerobic acidification fermentation process of the sludge in the phosphorus recovery module as the supplementary carbon source for the denitrification stage in the anoxic tank, and uses the nitrate nitrogen carried by the influent or part of the nitrate nitrogen carried by the reflux sludge to consume organic matter, achieving partial denitrification, thereby reducing the organic load of the aerobic tank; the sewage treated in the anoxic tank enters the aerobic tank, and the HRT of the aerobic tank is controlled to be 2.5 h, the DO concentration is 1.5 - 2.0 mg / L, and the aeration air-water ratio is about 15:1. In the aerobic tank, part of the organic matter with a high concentration in the sewage is consumed, and part of the ammonia nitrogen is converted into nitrate nitrogen, forming an appropriate nitrate / ammonia ratio, providing ammonia nitrogen conversion or nitrate nitrogen conditions for the subsequent shortcut nitrification-anaerobic ammonium oxidation treatment; the sewage treated in the aerobic tank enters the secondary sedimentation tank for sludge-water separation treatment, and the HRT of the secondary sedimentation tank is controlled to be about 2 h. Part of the settled sludge is refluxed to the anoxic tank, and the reflux ratio is about 50%, and the remaining part is discharged regularly, and the supernatant flows into the shortcut nitrification-anaerobic ammonium oxidation treatment module;

[0113] S3. Shortcut nitrification-anaerobic ammonium oxidation (PN / A) treatment, including: the effluent from the secondary sedimentation tank first enters the pre-adjustment tank of the shortcut nitrification-anaerobic ammonium oxidation treatment module for water volume adjustment; then it is fed into the reaction tank of the reaction module at a specific influent volume, and the shortcut nitrification and anaerobic ammonium oxidation integrated reaction are carried out simultaneously through the vertical rotating cage reactor in the reaction tank; among them, the carrier packing filled in the vertical rotating cage reactor is a composition of K3 packing and polyurethane packing with a volume ratio of 1:1, and the filling rate of the carrier packing in the vertical rotating cage reactor is about 60%; during the treatment process, the DO concentration in the reaction module is maintained at 0.3 - 0.6 mg / L, the HRT is 3 h, the pH is maintained at 7.0 - 8.0, the temperature is consistent with the front end, roughly at 25 ± 2 °C, and the rotation speed of the rotating cage reactor is controlled to be about 2 rpm to ensure uniform contact between the carrier packing and the sewage and not overly wear the biofilm; the effluent from the reaction module enters the sedimentation tank, and the HRT of the sedimentation tank is controlled to be 4 h. The sedimentation tank collects part of the suspended and non-fouled sludge in the sewage, and the effluent enters the biological aerated filter for further advanced treatment;

[0114] The main reaction equations of the above PN / A treatment process are as follows:

[0115]

[0116] S4. Terminal depth treatment, including: the effluent from the sedimentation tank enters the biological aerated filter (BAF). The filler of the biological aerated filter is sintered ceramsite with a particle size of 3 - 5 mm. The height of the filter bed is controlled at about 1.0 m, the DO concentration is controlled at 1.0 - 2.0 mg / L, and the filtration rate is about 6 m / h. Backwashing is carried out regularly (about every 5 - 7 days). The sewage is biochemically treated by the biological aerated filter to remove the residual nitrate nitrogen and a small amount of suspended solids in the effluent from the shortcut nitrification - anaerobic ammonium oxidation treatment module.

[0117] Treat the sewage according to the above treatment method. After the system operates continuously and stably for 30 days, sampling and testing analysis are carried out. Some of the obtained result data are shown in Table 1 below:

[0118] Table 1

[0119]

[0120] Note: In Table 1, "-" represents not detected or not having comparable significance; "removal rate" refers to the comprehensive removal rate of the corresponding pollutants from the influent to the final effluent of the overall process.

[0121] As can be seen from Table 1 above, through the above sewage treatment method, the ammonia nitrogen removal rate reaches 98.3%, indicating that the sewage treatment system and treatment method have good adaptability to high - ammonia - nitrogen wastewater and can achieve efficient denitrification; the total phosphorus finally drops to 1.0 mg / L, achieving good phosphorus removal effect; the terminal BAF effectively reduces the residual nitrate nitrogen in the PN / A effluent (from 10 mg / L to 2 mg / L), and the effluent can meet the standards stably; and the entire process system operates stably, without obvious sludge bulking or biofilm blockage problems, and the system can continuously maintain high - efficiency treatment under normal temperature and pressure.

[0122] Example 3

[0123] This example provides a sewage treatment method. This example is implemented using a sewage treatment system similar to that in Example 1. The difference between the sewage treatment system used in this example and that in Example 1 is that: in the carrier filler filled in the vertical rotating cage reactor in the reaction module of the shortcut nitrification - anaerobic ammonium oxidation treatment module in the sewage treatment system used in this example, the volume ratio of K3 filler and polyurethane filler is adjusted from 1:1 in Example 1 to 2:1, and the filling rate of the carrier filler remains 60%. Other parts are basically the same as the sewage treatment system in Example 1.

[0124] In addition, the specific operation of the sewage treatment method in this example is basically the same as that in Example 2. The differences include:

[0125] The water quality of the raw sewage is as follows: the ammonia nitrogen content is about 250 mg / L; the total phosphorus content (TP) is 10 mg / L; the COD is 800 mg / L; the pH is 7.0 ± 0.3; the temperature is 20 - 25 °C.

[0126] The main difference in the specific treatment process is that: during the phosphorus recovery treatment process in step S1 of this embodiment, the dosing amount of ferric chloride solution as the phosphorus remover is adjusted from 8 mg Fe 3+ / L in Example 2 to 5 mg Fe 3+ / L; in the short-cut nitrification-anaerobic ammonium oxidation treatment process of step S2, the volume ratio of K3 packing and polyurethane packing in the carrier packing filled in the vertical rotating cage reactor in the reaction module is adjusted from 1:1 in Example 2 to 2:1, the filling rate of the carrier packing remains 60%, the DO concentration in the reaction module is still 0.3 - 0.6 mg / L, and the HRT is shortened from 3 h in Example 2 to 2.5 h. Other treatments (including the anoxic tank, aerobic tank, secondary sedimentation tank, BAF, etc.) are generally the same as those in Example 2, and the residence time can be adjusted as appropriate during the treatment process to adapt to the lower influent load.

[0127] When sewage treatment is carried out according to the above treatment method, after the system has been running stably continuously for 20 days, sampling and testing analysis are carried out, and some of the obtained result data are shown in Table 2 below:

[0128] Table 2

[0129]

[0130] Note: In Table 2, "-" represents not detected or not having comparable significance; "removal rate" refers to the comprehensive removal rate of the corresponding pollutant by the overall process from the influent to the final effluent.

[0131] As can be seen from Table 2 above, through the above sewage treatment method for sewage treatment, the total phosphorus can still finally be reduced to below 1 mg / L, proving that reducing the dosing amount of the phosphorus remover (5 mg Fe 3+ / L) can still meet the phosphorus removal requirements for a lower influent phosphorus concentration; moreover, after the proportion of K3 packing in the carrier packing filled in the vertical rotating cage reactor of the reaction module increases, the biofilm attachment degree of ammonia-oxidizing bacteria and anaerobic ammonium-oxidizing bacteria to it significantly increases, and shortening the HRT can still maintain a high ammonia nitrogen removal rate; while the terminal BAF continues to play the role of removing residual nitrate nitrogen, reducing the nitrate nitrogen from 12 mg / L to 3 mg / L, and the effluent meets the discharge standards.

[0132] Example 4

[0133] This example proposes a sewage treatment method, which is basically the same as the sewage treatment method in Example 2, and the differences include:

[0134] The water quality of the raw sewage is as follows: the ammonia nitrogen content is about 200 mg / L; the total phosphorus content (TP) is 8 mg / L; the COD is 500 mg / L; the pH is 7.2 ± 0.2; the temperature is 10 - 15 °C (relatively low).

[0135] The main differences in the treatment process are as follows: in the anoxic-aerobic treatment process of step S2 and the shortcut nitrification-anaerobic ammonium oxidation treatment process of step S3 in this embodiment, temperature control devices are started, and the sewage temperatures in the aerobic tank and the reaction tank of the reaction module are respectively controlled in the range of 30 °C - 35 °C; moreover, in the anoxic-aerobic treatment process of this embodiment, the HRT of the anoxic tank is adjusted from 1.5 h in Example 2 to 2 h, and the DO concentration remains unchanged; and the HRT of the aerobic tank is adjusted from 2.5 h in Example 2 to 3 h, and the DO concentration remains unchanged; in the shortcut nitrification-anaerobic ammonium oxidation treatment process of this embodiment, the DO concentration in the reaction module is controlled at 0.3 - 0.5 mg / L, the HRT remains unchanged, and the vertical rotary cage reactor adopts a relatively low rotation speed (1 - 2 rpm) to reduce the negative impact caused by slow microbial growth due to low temperature. Other treatment operations are substantially the same as those in Example 2.

[0136] When sewage treatment is carried out according to the above treatment method, after the system operates stably continuously for 25 days, sampling and detection analysis are carried out, and some of the obtained result data are shown in Table 3 as follows:

[0137] Table 3

[0138]

[0139] Note: In Table 3, "-" represents not detected or having no comparable meaning; "removal rate" refers to the comprehensive removal rate of the corresponding pollutants from the influent to the final effluent by the overall process.

[0140] As can be seen from Table 3 above, through the above sewage treatment method for sewage treatment, by starting the temperature control system in the sewage treatment system to maintain the water temperatures in the aerobic tank and the reaction tank of the shortcut nitrification-anaerobic ammonium oxidation treatment module at 30 - 35 °C, the microbial flora (including shortcut nitrifying bacteria and anaerobic ammonium oxidizing bacteria) can maintain basic activity, achieving a total ammonia nitrogen removal rate of more than 90%; moreover, due to the slowdown of microbial growth under low temperature conditions, but in the reaction module of the shortcut nitrification-anaerobic ammonium oxidation treatment module, a vertical rotary cage reactor and a composite carrier filler filled with K3 filler and polyurethane filler are used, which can effectively provide the amount of bacteria and the stability of the biofilm, ensuring stable and efficient nitrogen removal; in addition, the terminal BAF can still effectively reduce the nitrate nitrogen to 4 mg / L, which can meet the general emission limit requirements.

[0141] As described above, the above sewage treatment system and sewage treatment method have successfully solved the problems of traditional high-ammonia-nitrogen wastewater treatment processes in terms of energy consumption, chemical consumption, sludge production, and participation in nitrate nitrogen removal. They have excellent treatment stability and the ability to ensure the effluent water quality for wastewater containing nutrients such as ammonia nitrogen and phosphorus, and have broad application prospects and significant economic and environmental benefits.

[0142] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention.

Claims

1. A sewage treatment system, characterized in that: include: A coagulation and sedimentation module is configured to at least perform coagulation and sedimentation treatment on the sewage to form sedimentation sludge and supernatant; a phosphorus recovery module, the phosphorus recovery module being connected to the coagulation and sedimentation module and configured to receive the precipitated sludge from the coagulation and sedimentation module and perform phosphorus recovery processing; An anoxic aerobic treatment module, the anoxic aerobic treatment module comprises an anoxic tank, an aerobic tank and a secondary sedimentation tank connected in sequence, the anoxic tank is connected to the coagulation sedimentation module, and is configured to receive the supernatant of the coagulation sedimentation module and perform anoxic treatment; The short-range nitrification-anaerobic ammonium oxidation treatment module comprises a reaction module, which is connected to the secondary sedimentation tank; the reaction module is filled with a carrier filler, which comprises a K3 filler and a polyurethane filler, and is configured to at least load short-range nitrifying bacteria and anaerobic ammonium oxidizing bacteria.

2. The sewage treatment system according to claim 1, characterized in that: The anoxic aerobic treatment module also includes a monitoring module and an aeration device. The monitoring module is configured to monitor the COD concentration and / or nitrate-nitrogen content of the inlet water of the anoxic aerobic treatment module; the aeration device is linked to the monitoring module and is configured to regulate the aeration amount to the aerobic pool according to the COD concentration and / or nitrate-nitrogen content of the inlet water of the anoxic aerobic treatment module.

3. The sewage treatment system according to claim 1, characterized in that: In the anoxic aerobic treatment module, a sludge return component is provided between the secondary sedimentation tank and the anoxic tank.

4. The sewage treatment system according to claim 1, characterized in that: The coagulation and sedimentation module comprises a coagulation and sedimentation reactor and a sand removal module connected to each other, the sand removal module has a water outlet and a mud discharge port, the phosphorus recovery module is connected to the mud discharge port, and the anoxic tank is connected to the water outlet; And / or, the phosphorus recovery module includes a sludge acidification reactor and a reaction sedimentation tank connected to each other; the sludge acidification reactor is connected to the coagulation sedimentation module and is configured to receive the sedimentation sludge of the coagulation sedimentation module and perform anaerobic acidification fermentation treatment; the reaction sedimentation tank is configured to perform precipitation reaction and separation and recovery treatment on the phosphorus released from the sedimentation sludge.

5. The sewage treatment system according to claim 1, characterized in that: The reaction module includes at least one reaction Unit, the reaction unit comprises a reaction tank and a cage reactor, the cage reactor is arranged in the reaction tank, and the carrier filler is filled in the cage reactor; preferably, the cage reactor is a vertical cage reactor.

6. The sewage treatment system according to claim 1, characterized in that: In the carrier filler, the mass ratio of the K3 filler to the polyurethane filler is (0.5-2):1; And / or, the filling rate of the carrier filler in the reaction module is 50% to 75%.

7. The sewage treatment system according to claim 1, characterized in that: The short-cut nitrification-anaerobic ammonium oxidation treatment module further includes at least one of a pre-regulation module and a sedimentation tank; the reaction module is connected to the secondary sedimentation tank via the pre-regulation module; the sedimentation tank is connected to the reaction module; And / or, the sewage treatment system also includes at least one of a temperature control device, an air fan, and a deoxygenation device; the temperature control device is configured to at least control the temperature of the reaction module; the air fan is configured to at least supply oxygen to the reaction module; the deoxygenation device is configured to at least deoxygenate the reaction module.

8. The sewage treatment system according to any one of claims 1 to 7, characterized in that: It also includes an aerated biological filter, which is connected to the short-range nitrification-anaerobic ammonium oxidation treatment module.

9. A method for treating sewage, characterized in that: The sewage treatment system according to any one of claims 1 to 8 is implemented; comprising: The sewage is passed into the coagulation and sedimentation module for coagulation and sedimentation treatment to form sedimentation sludge and supernatant; Passing the precipitated sludge into a phosphorus recovery module for chemical phosphorus recovery treatment; Passing the supernatant into an anoxic and aerobic treatment module to sequentially perform anoxic treatment, aerobic treatment and mud-water separation treatment; Short-cut nitrifying bacteria and anaerobic ammonium oxidizing bacteria are loaded on the carrier filler in the reaction module of the short-cut nitrification-anaerobic ammonium oxidation treatment module; the sewage treated by the anoxic aerobic treatment module is passed into the short-cut nitrification-anaerobic ammonium oxidation treatment module, and short-cut nitrification reaction and anaerobic ammonium oxidation reaction are carried out in the reaction module.

10. The sewage treatment method according to claim 9, characterized in that: The sewage treatment system described in claim 7 is used for implementation; the sewage treatment method further comprises: The sewage treated by the short-cut nitrification-anaerobic ammonium oxidation treatment module is passed into an aerated biological filter for biochemical treatment.

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