A sewage treatment system and method of treatment

Abstract

The application discloses a sewage treatment system and method, which comprises a coagulation and 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 coagulation and sedimentation module and is used for receiving the sedimentation sludge of the coagulation and 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 coagulation and sedimentation module. The PN / A treatment module comprises a reaction module which is connected with the secondary sedimentation tank and internally filled with carrier fillings. The carrier fillings comprise K3 fillings and polyurethane fillings and are used for at least loading short-cut nitrifying bacteria and anaerobic ammonia oxidation bacteria. The anoxic and aerobic treatment module can reduce system energy consumption and improve sewage treatment stability. The K3 fillings and the polyurethane fillings are used in the PN / A treatment module, which can be beneficial to rapid biofilm formation in the early stage of sewage treatment, stable biofilm in the later stage and improved treatment efficiency.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a wastewater treatment system and treatment method. Background Technology

[0002] Excessive discharge of nutrients such as nitrogen and phosphorus into wastewater can lead to eutrophication, which severely impacts aquatic ecosystems. To effectively control eutrophication, extensive research has been conducted both domestically and internationally on the removal of nitrogen and phosphorus from urban sewage, aquaculture wastewater, and industrial wastewater, resulting in a variety of technologies and processes.

[0003] While conventional biological nitrogen and phosphorus removal processes (such as A / O, A / A / O, and SBR processes) can achieve certain treatment effects in actual operation, they often suffer from problems such as high aeration energy consumption, large sludge production, and fluctuating treatment efficiency. In particular, for the treatment of wastewater with high ammonia nitrogen and high organic load, the investment and operating costs of conventional processes are often high, making it difficult to achieve compliant discharge in a high-efficiency, stable, and low-energy-consumption manner.

[0004] In recent years, the emergence of anammox technology has greatly promoted energy conservation and emission reduction in the treatment of high ammonia nitrogen wastewater. However, the pure anammox process has stringent requirements for influent conditions, start-up environment, and operating conditions, making it difficult to apply directly to actual industrial wastewater or municipal sewage.

[0005] To overcome the aforementioned limitations, the short-cut nitrification-anaerobic ammonium oxidation (PN / A) process has emerged. This process oxidizes ammonia nitrogen to nitrite through short-cut nitrification, and then anaerobic ammonium oxidation bacteria convert the remaining ammonia nitrogen and nitrite nitrogen into nitrogen gas. This significantly reduces carbon source and oxygen requirements, as well as sludge production, offering clear economic and environmental advantages in nitrogen removal. Furthermore, an integrated PN / A process has also emerged, where short-cut nitrification and anaerobic ammonium oxidation reactions occur simultaneously in a single reactor. The combined action of short-cut nitrifying bacteria (such as ammonia-oxidizing bacteria (AOB)) and anaerobic ammonium-oxidizing bacteria (AnAOB) achieves nitrogen removal from wastewater, significantly improving treatment efficiency.

[0006] In some current integrated treatment technologies, the UASB (Upflow Anaerobic Sludge Bed) carrier-free mode is often used to place short-range nitrifying bacteria (aerobic aerobic) and anaerobic ammonia oxidizing bacteria (absolute anaerobic) in the same completely mixed environment. However, the oxygen requirements of the two bacteria are completely different, and it is usually difficult to meet the growth conditions of both at the same time in a single reactor. The packing material used is usually difficult to balance biofilm formation rate and biofilm stability, 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 proposes a wastewater treatment system and treatment method.

[0008] A first aspect of the present invention provides a wastewater treatment system comprising:

[0009] The coagulation and sedimentation module is configured to at least treat wastewater by coagulation and sedimentation to form precipitated sludge and supernatant.

[0010] A phosphorus recovery module, which is connected to the coagulation and sedimentation module, is configured to receive the settled sludge from the coagulation and sedimentation module and perform phosphorus recovery treatment.

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

[0012] A short-cut nitrification-anaerobic ammonia oxidation treatment module includes a reaction module connected to the secondary sedimentation tank; the reaction module is filled with carrier packing material, which includes K3 packing material and polyurethane packing material, and is configured to support at least short-cut nitrifying bacteria and anaerobic ammonia oxidizing bacteria.

[0013] According to embodiments of the present invention, the wastewater treatment system has at least the following beneficial effects: The wastewater treatment system includes a coagulation sedimentation module, a phosphorus recovery module, an anoxic-aerobic treatment module, and a short-cut nitrification-anaerobic ammonium oxidation treatment module. The coagulation sedimentation module can be used to remove phosphorus and solid particulate impurities from the wastewater, thereby reducing the burden on subsequent biological units (including the short-cut nitrification-anaerobic ammonium oxidation treatment module) and lowering the risk of sludge bulking. The phosphorus recovery module enables efficient recovery and high-value utilization of phosphorus resources, improving economic efficiency. The anoxic-aerobic treatment module can be used to sequentially treat the effluent from the coagulation sedimentation module with anoxic, aerobic, and sludge-water separation processes. This reduces the oxygen consumption of the short-cut nitrification process in the short-cut nitrification-anaerobic ammonium oxidation treatment module, lowers system energy consumption, and makes it easier to control aeration volume and the type of dominant bacteria, thus improving the stability of wastewater treatment. Especially when the COD concentration or nitrate nitrogen content of the influent to the anoxic-aerobic treatment module is high, if the wastewater directly enters the short-cut nitrification-anaerobic ammonia oxidation treatment module after passing through the coagulation and sedimentation module, the short-cut nitrification process will increase oxygen consumption, which will increase the system energy consumption. Furthermore, the aeration rate is difficult to control, and it is impossible to accurately control the short-cut nitrifying bacteria to be the dominant bacteria. This will lead to the production of excessive nitrate nitrogen in the short-cut nitrification effluent, resulting in poor anaerobic ammonia oxidation reaction. However, the wastewater treatment system of this invention can effectively overcome the above problems by setting an anoxic-aerobic treatment module between the coagulation and sedimentation module and the short-cut nitrification-anaerobic ammonia oxidation treatment module, and the setting has obvious advantages. Furthermore, the anoxic tank in the anoxic-aerobic treatment module can utilize the nitrate nitrogen from the influent to consume organic matter, achieving partial denitrification and reducing the organic load on the aerobic tank. The aerobic tank can oxidize and remove the remaining organic matter in a sufficient dissolved oxygen environment, while simultaneously completing partial nitrification. This provides appropriate ammonia nitrogen conversion or nitrite nitrogen conditions for the reaction module of the subsequent short-cut nitrification-anaerobic ammonia oxidation treatment module, thereby improving treatment efficiency.

[0014] The reaction module of the short-cut nitrification-anaerobic ammonium oxidation treatment module is filled with carrier packing materials including K3 packing and polyurethane packing. This allows for the loading of microorganisms, including short-cut nitrifying bacteria and anaerobic ammonium oxidizing bacteria. The combination of K3 and polyurethane packing provides a diverse, high-specific-surface-area immobilization environment for the microorganisms. In particular, the unique porous sponge characteristics of the polyurethane packing allow for faster microbial accumulation on the packing material. This creates an internal anaerobic environment where anaerobic ammonium oxidizing bacteria accumulate, while the external aerobic environment enriches short-cut nitrifying bacteria. During mass transfer, water undergoes short-cut nitrification under the action of short-cut nitrifying bacteria, converting some ammonia nitrogen into nitrite. The nitrite then carries ammonia and nitrite into the packing material, where anaerobic ammonium oxidizing bacteria convert ammonia and nitrite into nitrogen gas. This allows for effective synergistic action between short-cut nitrifying bacteria and anaerobic ammonium oxidizing bacteria, improving system stability, reducing aeration requirements, and significantly decreasing sludge production. Polyurethane sponge filler has a fast biofilm formation rate and can rapidly enrich biofilm in a short period of time, but long-term use can easily create dead zones. K3 filler has a slow biofilm formation rate, but the biofilm is stable and less likely to create dead zones. The combination of the two can help ensure rapid biofilm formation in the early stage and stable biofilm in the later stage, thereby improving treatment efficiency.

[0015] During the research process, the inventors conducted in-depth studies on the carrier packing materials used to support short-cut nitrifying bacteria and anaerobic ammonia oxidizing bacteria in the short-cut nitrification-anaerobic ammonia oxidation treatment module. This included research experiments using other different carrier packing materials, revealing various problems with each. For example, using K3 packing material alone, PP hollow ball packing material, or a combination of both to support short-cut nitrifying bacteria and anaerobic ammonia oxidizing bacteria present difficulties in biofilm formation and the creation of an inner and outer layered environment. Bio-rope packing material, on the other hand, easily traps fibers and other substances that may be present in the influent, making it difficult to manage. Therefore, this invention selects a carrier packing material that includes both K3 packing material and polyurethane packing material. Furthermore, in some embodiments, the carrier packing material consists only of K3 packing material and polyurethane packing material.

[0016] In some embodiments of the present invention, the mass ratio of the K3 filler to the polyurethane filler in the carrier packing is (0.5–2):1. For example, the mass ratio of K3 filler to polyurethane filler can be any one or any two of the following: 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. By controlling the mass ratio of K3 filler to polyurethane filler within the above range, rapid biofilm formation in the early stage and stable biofilm in the later stage can be effectively guaranteed.

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

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

[0019] In some embodiments of the present invention, the short-range 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 configured to supply oxygen 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 COD concentration and / or nitrate nitrogen content of the influent to the anoxic-aerobic treatment module. The aeration device is linked to the monitoring module and is configured to adjust the aeration rate to the aerobic tank according to the COD concentration and / or nitrate nitrogen content of the influent to the anoxic-aerobic treatment module.

[0022] In some embodiments of the present invention, a sludge return component is provided between the secondary sedimentation tank and the anoxic tank in the anoxic treatment module. By providing the sludge return component, a portion of the sludge from the secondary sedimentation tank can be returned to the anoxic tank, enhancing the biomass of denitrifying bacteria and other facultative anaerobic microorganisms in this section, forming an anoxic-aerobic cycle, thereby improving treatment efficiency; while the remaining sludge can be periodically removed from the system for external disposal or further treatment as needed.

[0023] The coagulation and sedimentation module is configured to at least treat wastewater by coagulation and sedimentation to form precipitated sludge and supernatant. In some embodiments, the coagulation and sedimentation module includes a coagulation and sedimentation reactor, which may be a coagulation and sedimentation reaction tank, a coagulation and sedimentation reaction vessel, etc. In a specific wastewater treatment process, wastewater is first introduced into the coagulation and sedimentation reactor. A coagulant including a phosphorus removal agent is added to the coagulation and sedimentation module to react the phosphorus in the wastewater with the phosphorus removal agent to form phosphorus-containing flocs. The phosphorus-containing flocs and large particulate suspended solids originally contained in the wastewater are removed. Then, the sludge, including the phosphorus-containing flocs and large particulate solid impurities, is introduced into a phosphorus recovery module for chemical phosphorus recovery treatment. The resulting supernatant (i.e., the wastewater after treatment in this section) is used as pretreated wastewater and introduced into anoxic-aerobic treatment module, which can improve wastewater treatment efficiency.

[0024] In some embodiments of the present invention, the coagulation and sedimentation module further includes a phosphorus removal agent storage container connected to the coagulation and sedimentation reactor. The phosphorus removal agent storage container is configured to store phosphorus removal agent and supply it to the coagulation and sedimentation reactor; the phosphorus removal agent may be iron salt or other phosphorus removal agents. This design facilitates precise dosing of the phosphorus removal agent and reduces agent waste.

[0025] In some embodiments of the present invention, the coagulation sedimentation module further includes a sand removal module connected to the coagulation sedimentation reactor. The sand removal module has an outlet and a sludge discharge outlet. The outlet is connected to the anaerobic tank, and the sludge discharge outlet is connected to the phosphorus recovery module. By including the sand removal module, the efficiency of phosphorus and sand removal from wastewater can be improved, effectively reducing the burden on subsequent wastewater treatment, while simultaneously increasing the phosphorus recovery rate.

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

[0027] In some embodiments of the present invention, the phosphorus recovery module includes a sludge acidification reactor and a reaction sedimentation tank connected together; the sludge acidification reactor is connected to the coagulation sedimentation module and is configured to receive the precipitated sludge from 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 precipitated 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 removal agent used in the coagulation and precipitation module process is an iron salt.

[0029] In the specific wastewater treatment process, the sludge discharged from the coagulation and sedimentation module enters the sludge acidification reactor of the phosphorus recovery module for anaerobic acidification fermentation. The organic matter in the sludge is acidified and hydrolyzed into small molecule organic compounds such as acetic acid and propionic acid, which can promote the pH of the system to about 4. Phosphorus dissolves and is released into the liquid phase under the acidification hydrolysis and biodissimilatory iron reduction. Ferrous ions are also released during the anaerobic acidification fermentation process. Then, it is introduced into the reaction sedimentation tank. Based on the theory of iron and phosphorus flocculation and sedimentation, the redox potential (ORP) in the sludge fermentation liquid can be adjusted by adding oxidants such as hydrogen peroxide to the reaction sedimentation tank. The ferrous ions released by the acidification fermentation of sludge are oxidized into ferric ions. Then, the pH is adjusted to acidic conditions to react and form ferric phosphate precipitate, achieving efficient separation and recovery.

[0030] In some embodiments, the outlet of the reaction sedimentation tank can be connected to the anoxic tank, thereby allowing the supernatant from the reaction sedimentation tank to be transported to the anoxic tank. This enables the volatile fatty acids (VFAs) generated and accumulated during the sludge acidification and fermentation process to be fully utilized as a supplementary carbon source for the denitrification stage of the wastewater anoxic tank unit. This reduces the cost of adding and operating carbon sources while increasing the benefits of wastewater resource utilization. As a result, efficient recovery and high-value-added utilization of carbon and phosphorus resources can be achieved simultaneously, resulting in significant economic benefits.

[0031] The short-cut nitrification-anaerobic ammonium oxidation (ATAO) treatment module is a short-cut nitrification-anaerobic ammonium oxidation (ATAO) reaction module. Wastewater to be treated can be denitrified within this module through short-cut nitrification and anaerobic ammonium oxidation reactions. Furthermore, the reaction module is an integrated short-cut nitrification-anaerobic ammonium oxidation (ATAO) reaction module. During wastewater treatment, short-cut nitrifying bacteria and anaerobic ammonium oxidizing bacteria are loaded onto the carrier packing material of the reaction module. Under low dissolved oxygen (or anoxic) conditions, the short-cut nitrifying bacteria partially oxidize ammonia nitrogen to nitrite nitrogen, while the anaerobic ammonium oxidizing bacteria couple nitrite nitrogen with the remaining ammonia nitrogen to convert it into nitrogen gas. Therefore, to maintain the short-cut nitrification process in an "anoxic" state rather than a "completely aerobic" state, only a small amount of air needs to be added to the reaction module to ensure that the survival conditions of both short-cut nitrifying bacteria and anaerobic ammonium oxidizing bacteria are met, thereby significantly reducing oxygen demand and the need for external carbon sources.

[0032] In some embodiments of the present invention, the reaction module includes at least one reaction unit, which includes a reaction tank and a rotating drum reactor. The rotating drum reactor is located within the reaction tank, and the carrier packing material is filled within the rotating drum reactor. During the treatment process, wastewater can enter the reaction tank and come into contact with the carrier packing material loaded with short-range nitrifying bacteria and anaerobic ammonia oxidizing bacteria through the rotating drum reactor. Under the action of the short-range nitrifying bacteria and anaerobic ammonia oxidizing bacteria, short-range nitrification and anaerobic ammonia oxidation reactions occur. By constructing the reaction module with a rotating drum reactor within the reaction tank, the system's controllability for wastewater treatment is enhanced, the bacterial load and biofilm stability (or microbial load stability) are improved, and by controlling the rotation of the rotating drum reactor, the carrier packing material can be made to contact the wastewater evenly, reducing clogging caused by excessive biofilm growth, thereby improving the efficiency and stability of wastewater treatment.

[0033] In some embodiments of the present invention, the rotating cage reactor is a vertical rotating cage reactor. Further, the vertical rotating cage reactor may be designed to include a rotating shaft, a rotating cage, and a partition plate; the rotating cage is disposed within the reaction tank via the rotating shaft and configured such that the rotating cage can rotate along the rotating shaft; the partition plate is disposed within the rotating cage and divides the rotating cage into at least two partitions along the radial direction of the rotating cage; each partition is filled with the carrier packing material, and the carrier packing material is separated and confined within each partition by the partition plate. Further, the rotating cage may be designed with a grid-like outer frame, and the particle size of the carrier packing material is generally larger than the pore size of the rotating cage's outer frame; if the partition plate also has through holes, the particle size of the carrier packing material is generally also larger than the pore size of the partition plate.

[0034] By combining the addition of K3 packing and polyurethane packing, and by setting up a vertical rotary drum reactor, it is beneficial to achieve the composite zone attachment and synergistic growth of two types of functional bacteria: short-range nitrifying bacteria and anaerobic ammonia oxidizing bacteria, and to significantly improve the shock resistance.

[0035] In some embodiments of the present invention, the reaction unit is one.

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

[0037] In some embodiments of the present invention, the short-cut nitrification-anaerobic ammonia oxidation treatment module further includes at least one of a pre-conditioning 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 mud-water separation treatment on the effluent from the reaction module.

[0040] In some embodiments of the present invention, a wastewater recirculation component may also be provided between the sedimentation tank and the pre-conditioning module in the short-cut nitrification-anaerobic ammonium oxidation treatment module.

[0041] In some embodiments of the present invention, the pre-regulation module is configured to regulate the influent flow into the reaction module in order to control the wastewater to react fully and effectively within 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 fan, and a deoxygenation device;

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

[0044] The temperature control device is configured to control the temperature of the reaction module at least to ensure the activity of short-range nitrifying bacteria and anaerobic ammonia oxidizing bacteria during wastewater treatment and to ensure denitrification efficiency. For example, the temperature control device may employ heating devices such as electric heating tubes or heat exchangers to maintain the wastewater in the reaction module at a suitable growth temperature (e.g., 30°C to 35°C) for short-range nitrifying bacteria and anaerobic ammonia oxidizing bacteria during treatment, thereby ensuring bacterial activity. In some embodiments, the temperature control device is also configured to control the temperature of the aerobic tank in the anoxic-aerobic module. Further, the temperature control device may also include a heat insulation device; the heat insulation device may be a heat insulation layer disposed 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 deoxygenation device is further configured to deoxygenate the anoxic tank.

[0046] In some embodiments of the present invention, the deoxygenation device includes an inert gas generator and an inert gas blower; the inert gas generator is configured to generate inert gas, and is connected to a reaction module and / or anoxic tank; the inert gas blower is used to blow the inert gas generated by the inert gas generator to the reaction module and / or anoxic tank to control the dissolved oxygen content of the wastewater therein. The inert gas generator may be a nitrogen generator, and the inert gas blower may be a nitrogen blower.

[0047] The PN / A process inevitably produces a small amount of nitrate nitrogen. Without a proper subsequent treatment unit, the effluent may still not consistently meet discharge standards. Therefore, to further ensure stable effluent discharge that meets standards, in some embodiments of this invention, the wastewater treatment system also includes an aerated biological filter connected to the short-cut nitrification-anaerobic ammonium oxidation (SAO) treatment module. By using the aerated biological filter, the effluent from the SAO module undergoes further advanced treatment, removing residual nitrate nitrogen and a small amount of suspended solids, ensuring stable effluent discharge that meets standards, and improving the system's adaptability to water quality fluctuations, thus enhancing the stability and reliability of the wastewater treatment system.

[0048] The aerated biological filter is filled with filter media, which can be granular or modular, and generally uses media with high biological activity and high porosity. Specifically, the filter media can be sintered ceramics, volcanic rock, synthetic bioceramic granules, etc.

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

[0050] A second aspect of the present invention provides a wastewater treatment method, which is implemented using any of the aforementioned wastewater treatment systems of the present invention, comprising:

[0051] Wastewater is fed into a coagulation and sedimentation module for coagulation and sedimentation treatment, forming precipitated sludge and supernatant.

[0052] The precipitated sludge is fed into a phosphorus recovery module for chemical phosphorus recovery treatment.

[0053] The supernatant is passed into the anoxic and aerobic treatment module and undergoes anoxic treatment, aerobic treatment, and mud-water separation treatment in sequence.

[0054] Short-cut nitrifying bacteria and anaerobic ammonia oxidation bacteria are loaded onto the carrier packing material in the reaction module of the short-cut nitrification-anaerobic ammonia oxidation treatment module; the wastewater treated by the anoxic-aerobic treatment module is introduced into the short-cut nitrification-anaerobic ammonia oxidation treatment module, and short-cut nitrification and anaerobic ammonia oxidation reactions are carried out in the reaction module.

[0055] In the above wastewater treatment methods, the wastewater is first treated by an anoxic-aerobic treatment module before entering the short-cut nitrification-anaerobic ammonia oxidation treatment module. This reduces the oxygen consumption of the short-cut nitrification process in the short-cut nitrification-anaerobic ammonia oxidation treatment module, lowers system energy consumption, and makes it easier to control the aeration rate and the type of dominant bacteria, thus improving the stability of wastewater treatment, especially when the influent COD concentration and nitrate nitrogen content are too high. Furthermore, the nitrate nitrogen in the influent can be used to consume some organic matter, and some ammonia nitrogen can be converted into nitrite nitrogen, providing treatment conditions for the subsequent PN / A reactor, thereby improving wastewater treatment efficiency.

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

[0057] Specifically, iron salts can be added according to the influent flow rate ratio, and the dosage can be adjusted based on the phosphorus concentration in the wastewater. In some embodiments of the present invention, the dosage of iron salts can be based on Fe... 3+ With PO4 3- The molar ratio is controlled at (1.5–2.5):1. For example, Fe 3+ With PO4 3- The molar ratio can be any value or a range of any two of the following: 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.

[0058] The coagulation and sedimentation treatment time can be controlled between 5 and 15 minutes, depending on the water quality and coagulation effect. For example, the reaction time can be controlled to any value or a range of any two of the following: 5 minutes, 7 minutes, 8 minutes, 10 minutes, 12 minutes, 13 minutes, and 15 minutes. Stirring can be used as an adjunct to the coagulation and sedimentation process; the stirring rate should be sufficient to maintain uniform mixing.

[0059] If the pH of the influent to the coagulation and sedimentation module is too low (e.g., less than 6.0) or too high (e.g., greater than 9.0), appropriate adjustments are necessary to ensure the formation of stable iron-phosphorus flocs after the iron salt is added. Therefore, in some embodiments of this invention, the pH of the wastewater is adjusted before it is introduced into the coagulation and sedimentation module for coagulation and sedimentation treatment. Specifically, the pH of the wastewater can be adjusted and controlled between 6.5 and 8.5. For example, the pH value of the wastewater can be controlled within any value or a range of any two of the following: 6.5, 6.8, 7.0, 7.2, 7.5, 7.6, 7.8, 8.0, 8.2, and 8.5.

[0060] After coagulation and sedimentation, sand removal treatment can be used to remove large suspended solids and sand from wastewater, reducing or even avoiding the solid load of subsequent systems and the risk of blockage or operation due to excessive suspended solids or large particles; at the same time, the flocs or sediment generated by coagulation and sedimentation treatment can be removed, achieving rapid and efficient phosphorus and sand removal from wastewater.

[0061] In some embodiments of the present invention, the influent flow velocity can be controlled between 0.8 m / s and 1.2 m / s during the sand removal process. For example, the influent flow velocity can be any value or a range of any two of 0.8 m / s, 0.9 m / s, 0.95 m / s, 1.0 m / s, 1.1 m / s, 1.15 m / s, and 1.2 m / s. The sand removal process can involve periodic or continuous discharge of settled sand.

[0062] Sludge from coagulation and sedimentation or sludge from sand removal can be fed into a phosphorus recovery module for chemical phosphorus recovery. In some embodiments, the sludge can first undergo anaerobic acidification fermentation to dissolve and release phosphorus and iron ions. Then, an oxidant is added to oxidize the ferrous ions released during the anaerobic acidification fermentation to ferric ions. The pH of the system is then adjusted to acidity to react and form ferric phosphate precipitate, thereby achieving efficient separation and recovery of phosphorus. Specifically, the sludge can first be fed into the sludge acidification reactor of the phosphorus recovery module in the wastewater treatment system for anaerobic acidification fermentation, and then fed into a reaction sedimentation tank for sedimentation reaction and separation and recovery. In some embodiments, the supernatant obtained from the reaction sedimentation tank can also be transported to an anoxic tank so that the VFAs generated and accumulated during the sludge acidification fermentation process can be fully utilized as a supplementary carbon source for the denitrification stage of the wastewater anoxic tank unit. This reduces the operating costs of carbon source addition while increasing the benefits of wastewater resource utilization, thereby achieving efficient recovery and high-value-added utilization of carbon and phosphorus resources.

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

[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 within 1h to 2h. For example, the HRT can be any value or a range of any two of 1h, 1.2h, 1.5h, 1.6h, 1.8h, and 2h, and can be appropriately adjusted according to the concentration of organic matter and nitrate nitrogen in the influent.

[0065] In some embodiments of the present invention, the dissolved oxygen concentration of the wastewater in 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 or a range of any two of the following: 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, and 2.5 mg / L.

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

[0067] In addition, if the influent water temperature of the aerobic tank during the aerobic treatment process is too low (e.g., less than 15℃), aeration can be appropriately increased or the temperature control device can be activated to maintain the activity of nitrifying bacteria.

[0068] In some embodiments of the present invention, part of the sludge produced by the sludge-water separation treatment in the secondary sedimentation tank of the anoxic-aerobic treatment module is returned 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 remaining sludge can be discharged from the system periodically for external disposal or further treatment as needed.

[0069] When wastewater treated by the anoxic-aerobic treatment module is fed into the reaction module for further treatment, only a very small amount of air needs to be added to the reaction module. Specifically, the dissolved oxygen (DO) concentration in the reaction module can be controlled to be between 0.3 mg / L and 0.6 mg / L. For example, the dissolved oxygen concentration can be any value or a range of any two of the following: 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, and 0.6 mg / L. This maintains an "anoxic" state in the reaction module rather than a "completely aerobic" state, ensuring that the survival conditions of both short-range nitrifying bacteria and anaerobic ammonia oxidizing bacteria are taken into account.

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

[0071] The optimal temperature for anaerobic ammonia oxidation is generally between 30℃ and 35℃. Therefore, the temperature within the reaction module during processing can be maintained between 30℃ and 35℃. For example, the temperature can be controlled within any value or a range of both 30℃, 32℃, 33℃, and 35℃. If the water temperature is too low, a temperature control device can be used for adjustment. Furthermore, the pH value of the wastewater within the reaction module can be controlled within the range of 7.0 to 8.0. For example, the wastewater pH value can be controlled within any value or a range of both 7.0, 7.2, 7.3, 7.5, 7.6, 7.8, and 8.0.

[0072] In some embodiments of the present invention, the reaction module includes a rotary drum reactor. During the wastewater treatment process, the rotary drum reactor is generally kept rotating at a low speed. Specifically, the rotation speed of the rotary drum reactor can be controlled between 1 rpm and 5 rpm. For example, its rotation speed can be any value or a range of any two of 1 rpm, 1.5 rpm, 2 rpm, 2.5 rpm, 3 rpm, 4 rpm, 4.5 rpm, and 5 rpm to avoid excessive scouring of the microbial film.

[0073] In some embodiments of the present invention, the wastewater treatment method employs any of the aforementioned wastewater treatment systems including an aerated biological filter; and the wastewater treatment method further includes: passing the wastewater treated by the short-cut nitrification-anaerobic ammonia oxidation treatment module into the aerated biological filter for biochemical treatment. This further removes nitrate nitrogen, suspended solids, microbial metabolites, etc., from the wastewater, ensuring that the effluent meets or exceeds the corresponding discharge standards for direct discharge or reuse.

[0074] During the biological treatment process, the dissolved oxygen concentration of wastewater in the aerated biological filter can be controlled between 1 mg / L and 2 mg / L. For example, the dissolved oxygen concentration can be any value or a range of any two of the following: 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, and 2 mg / L. This is achieved by maintaining light aeration or intermittent aeration. Furthermore, the filtration rate of the aerated biological filter can be controlled between 4 m / h and 10 m / h. For example, the filtration rate can be any value or a range of any two of the following: 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, and 10 m / h. This can be adjusted according to the treatment scale and target effluent indicators. Furthermore, the filter bed can be backwashed periodically to remove the accumulated biofilm aging layer and solid deposits, thus maintaining the long-term stability of the filtration function. Attached Figure Description

[0075] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0076] Figure 1 This is a schematic diagram of the structure of an embodiment of the wastewater treatment system of the present invention;

[0077] Figure 2 for Figure 1 The diagram shows a flow chart of the wastewater treatment system.

[0078] Figure 3 for Figure 1 The diagram shows the structure of a vertical rotary drum reactor in the wastewater treatment system. Detailed Implementation

[0079] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0080] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein 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 with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0081] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0082] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0083] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0084] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0085] Example 1

[0086] This embodiment proposes a wastewater treatment system, such as Figure 1 and Figure 2 As shown, the wastewater treatment system includes a coagulation and sedimentation module, a phosphorus recovery module, an anoxic and aerobic treatment module, a short-cut nitrification-anaerobic ammonia oxidation treatment module, and an aerated biological filter.

[0087] The system includes a coagulation and sedimentation module for treating wastewater through coagulation and sedimentation and removing sand, forming precipitated sludge and supernatant to remove phosphorus and particulate impurities. The resulting supernatant is then used as pretreated wastewater and fed into the anoxic-aerobic treatment module for further treatment. A phosphorus recovery module is connected to the coagulation and sedimentation module and is configured to receive the precipitated sludge from the coagulation and sedimentation module and perform phosphorus recovery treatment. The anoxic-aerobic treatment module is configured to sequentially treat the effluent from the coagulation and sedimentation module through anoxic treatment, aerobic treatment, and sludge-water separation. A short-cut nitrification-anaerobic ammonia oxidation treatment module is configured to denitrify the wastewater. An aerated biological filter is configured to further treat the effluent from the short-cut nitrification-anaerobic ammonia oxidation treatment module to remove residual nitrate nitrogen and a small amount of suspended solids.

[0088] The coagulation and sedimentation module specifically includes a coagulation and sedimentation reactor 11 and a sand removal module 12 connected to each other. In this embodiment, the coagulation and sedimentation module also includes a phosphorus removal agent storage container 13, which is connected to the coagulation and sedimentation reactor 11 and used to store and supply phosphorus removal agent to the coagulation and sedimentation reactor 11. The coagulation and sedimentation reactor 11 is connected to the sand removal module 12. A stirring device may be installed inside the phosphorus removal agent storage container 13 to prevent the phosphorus removal agent from settling during storage and ensure that the phosphorus removal agent remains evenly distributed during storage. The coagulation and sedimentation reactor 11 may be a coagulation and sedimentation reaction tank, coagulation and sedimentation reaction vessel, etc., and may be equipped with a stirring device to ensure that the phosphorus removal agent and wastewater are fully mixed during the wastewater treatment process, thereby improving reaction efficiency. The sand removal module 12 is connected to the short-cut nitrification-anaerobic ammonium oxidation treatment module and the phosphorus recovery module (not shown in the figure). Specifically, the sand removal module 12 has an outlet and a sludge discharge port. The outlet of the sand removal module 12 is connected to the inlet of the short-cut 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 sand separator. In the wastewater treatment process, the wastewater is first introduced into the coagulation sedimentation reactor 11. The phosphorus removal agent storage container 13 provides phosphorus removal agent into the coagulation sedimentation reactor 11 so that the phosphorus element in the wastewater reacts with the phosphorus removal agent to form phosphorus-containing flocs. Then, it is introduced into the sand removal module 12 to remove the phosphorus-containing flocs and large particulate solid impurities in the wastewater before entering the anoxic-aerobic treatment module. 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 sludge acidification reactor and a reaction sedimentation tank connected to each other; the sludge acidification reactor is connected to the sludge discharge port of the sand removal module 12 and is configured to receive the settled 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 and recovery treatment of phosphorus released from the settled 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. Anoxic tank 21 is connected to a sand removal module 12, and secondary sedimentation tank 23 is connected to a short-cut nitrification-anaerobic ammonia oxidation treatment module. A sludge return component (not shown in the figure) is provided between secondary sedimentation tank 23 and anoxic tank 21. Specifically, the inlet of anoxic tank 21 is connected to the outlet of sand removal module 12, and the outlet of anoxic tank 21 is connected to the inlet of aerobic tank 22; the outlet of aerobic tank 22 is connected to the inlet of secondary sedimentation tank 23, and the outlet of secondary sedimentation tank 23 is connected to the inlet of the short-cut nitrification-anaerobic ammonia oxidation treatment module. A stirring device 211 can be installed in anoxic tank 21 to enhance mass transfer, improve water quality uniformity, and accelerate the reaction. During the wastewater treatment process, the effluent from the sand removal module 12 can be sequentially passed through the anoxic tank 21, aerobic tank 22, and secondary sedimentation tank 23 of the anoxic-aerobic treatment module, respectively, to undergo anoxic treatment, aerobic treatment, and sludge-water separation treatment. The wastewater separated in the secondary sedimentation tank 23 is then fed into the short-cut nitrification-anaerobic ammonia oxidation treatment module for further treatment. Part of the sludge is returned to the anoxic tank 21 to enhance the biomass of denitrifying bacteria and other facultative anaerobic microorganisms. The remaining sludge can be periodically discharged from the system.

[0091] In addition, the outlet of the reaction sedimentation tank in the phosphorus recovery module is connected to the anoxic tank 21, so that the supernatant of the reaction sedimentation tank can be transported to the anoxic tank 21. This allows the VFAs generated and accumulated during the sludge acidification and fermentation process to be fully utilized as a supplementary carbon source for the denitrification stage of the wastewater anoxic tank unit. This reduces the cost of adding and operating carbon sources while increasing the benefits of wastewater resource utilization. Thus, it is possible to achieve efficient recovery and utilization of phosphorus resources, as well as efficient recovery and high-value-added utilization of carbon resources.

[0092] The anoxic-aerobic treatment module may also 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 may be designed to be linked with the monitoring module and configured to adjust the aeration rate 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). In the specific operation process, when the monitoring module detects that the COD concentration and / or nitrate nitrogen content of the influent to the anoxic-aerobic treatment module (or the influent to the anoxic tank 21) is too high, the aeration rate of the aeration device to the aerobic tank 22 can be increased; when the monitoring module detects that the COD concentration and nitrate nitrogen concentration of the influent to the anoxic-aerobic treatment module (or the influent to the anoxic tank 21) are low, the aeration rate of the aeration device to the aerobic tank 22 can be reduced. In this way, the system energy consumption can be effectively reduced while ensuring treatment efficiency.

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

[0094] In this embodiment, the reaction module 32 includes three reaction units, each of which includes a reaction tank 321 and a rotary drum reactor 322. The reaction tanks 321 of each reaction unit are connected in sequence, and the rotary drum reactor 322 is located inside the reaction tank 321. Specifically, it is a vertical rotary drum reactor, and its structure is as follows. Figure 3 As shown, the reactor includes a rotating shaft 3221, a rotating cage 3222, and a partition plate 3223. The rotating cage reactor 322 is located within the reaction tank 321 via the rotating shaft 3221 and is configured such that the rotating cage 3222 can rotate along the rotating shaft 3221. The partition plate 3223 is located within the rotating cage 3222 and divides the rotating cage 3222 into four sections along its radial direction. Each section is uniformly filled with carrier packing material, which is used to load short-range nitrifying bacteria and anaerobic ammonia oxidizing bacteria. In this embodiment, the carrier packing material is a mixture of K3 packing material and polyurethane packing material in a 1:1 volume ratio. The filling rate of the carrier packing material in the rotating cage reactor 322 is approximately 30%, and the short-range nitrifying bacteria loaded on the carrier packing material are ammonia oxidizing bacteria. The pre-conditioning module 31 specifically adopts a pre-conditioning tank.

[0095] A pre-regulation module 31 is installed before the reaction module 32 to regulate the influent flow rate into the reaction module. A sedimentation tank 33 is installed after the reaction module 32, which is configured to perform sludge-water separation treatment on the effluent from the reaction module 32. In addition, a wastewater return component is installed between the sedimentation tank 33 and the pre-regulation module 31.

[0096] The aerated biological filter 40 is connected to the short-cut nitrification-anaerobic ammonium oxidation (ATAO) treatment module. Specifically, the inlet of the aerated biological filter 40 is connected to the outlet of the sedimentation tank 33 in the ATAO module. The aerated biological filter 40 is filled with filter media, specifically sintered ceramsite with a particle size of 3mm to 5mm. The filter bed height in the aerated biological filter 40 is approximately 1.0m. Through the installation of the aerated biological filter 40, the effluent from the ATAO module undergoes further advanced treatment, removing residual nitrate nitrogen and a small amount of suspended solids, ensuring stable effluent discharge that meets standards, and improving the system's adaptability to water quality fluctuations, thereby enhancing the stability and reliability of the wastewater treatment system.

[0097] In addition, the wastewater treatment system in this embodiment also includes a temperature control device (not shown in the figure), an air blower 50, and a deoxygenation device. The temperature control device includes an electric heating element and an insulation layer. The insulation layer is located outside the aerobic tank 22 and the reaction tank 321 of the reaction module 32. The electric heating element is configured to heat the wastewater in the aerobic tank 22 and the reaction tank 321 when the temperature of the wastewater to be treated is lower than a predetermined lower limit temperature during the wastewater treatment process, 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 aerated biological filter 40 in the short-cut nitrification-anaerobic ammonium oxidation treatment module in the anaerobic-aerobic treatment module during the wastewater treatment process. Furthermore, in this embodiment, the aeration device of the anoxic-aerobic treatment module is the air blower 50, that is, the aeration and oxygen supply of the reaction tank 321, the aerated biological filter 40, and the aerobic tank 22 in the anoxic-aerobic treatment module can share the same device, thereby simplifying the system structure and saving the system layout area. The deoxygenation device is configured for deoxygenation in the reaction tank 321 of the short-cut nitrification-anaerobic ammonium oxidation treatment module in the wastewater treatment process. The deoxygenation device specifically includes a nitrogen generator 61 and a nitrogen blower 62. The nitrogen generator 61 is connected to the reaction tank 321 of the reaction module 32, and the nitrogen blower 62 is used to blow the nitrogen generated by the nitrogen generator 61 to the reaction module 32 to control the dissolved oxygen content of the wastewater therein.

[0098] When using the above wastewater treatment system, wastewater can be fed into the coagulation sedimentation reactor 11, and phosphorus removal agent can be supplied to the coagulation sedimentation reactor 11 through the phosphorus removal agent storage container 13. This allows the wastewater and phosphorus removal agent to mix and react, forming iron-phosphorus flocs. Simultaneously, some undegraded organic matter forms organic flocs after coagulation and sedimentation. The reacted wastewater is then fed into the sand removal module 12, where sludge containing iron-phosphorus flocs, other large suspended solids, and sand is removed. The sludge is then fed into the sludge acidification reactor of the phosphorus recovery module for anaerobic acidification and fermentation treatment to remove the sludge. Phosphorus and ferrous ions are released from the fermentation broth, which is then fed into a reaction sedimentation tank. An oxidant is added to oxidize the ferrous ions to ferric ions, and a pH adjuster is added to adjust the pH of the system to acidity, so that ferric phosphate precipitate is formed and then separated and recovered. The supernatant from the reaction sedimentation tank can be transported to the anoxic tank 21 to supplement the carbon source for the anoxic tank. The effluent from the sand removal module 12 is fed into the anoxic tank 21 of the anoxic-aerobic treatment module. In the anoxic tank 21, the wastewater uses the nitrate nitrogen from the influent (or part of the nitrate nitrogen from the returned sludge) to consume organic matter, achieving partial denitrification and reducing the organic load on the aerobic tank 22. Wastewater treated in anoxic tank 21 enters aerobic tank 22, where, under sufficient dissolved oxygen, the remaining organic matter is oxidized and partially nitrified, providing adequate ammonia nitrogen conversion or nitrate nitrogen conditions for subsequent short-cut nitrification-anaerobic ammonium oxidation treatment. Wastewater treated in aerobic tank 22 then enters secondary sedimentation tank 23 for sludge-water separation. Sludge from the mixed liquor settles and is partially returned to anoxic tank 21; remaining sludge is periodically discharged for external or further treatment as needed. The separated wastewater then enters the pre-regulation module 31 of the short-cut nitrification-anaerobic ammonium oxidation treatment module. Wastewater introduced from the anoxic / aerobic treatment module is regulated in quantity by the pre-regulation module 31. After the holiday, the wastewater enters the reaction tanks 321 of each reaction unit in the reaction module 32 in sequence. In each reaction tank 321, short-cut nitrification and anaerobic ammonia oxidation are carried out simultaneously in the vertical rotating cage reactor 322 to remove ammonia nitrogen. The effluent from the reaction module 32 enters the sedimentation tank 33 to collect some of the suspended and non-film-coated sludge in the wastewater. Depending on the actual situation, at least part of the wastewater can be returned to the pre-conditioning module 31. The effluent from the sedimentation tank 33 enters the aerated biological filter 40 for further deep treatment to remove residual nitrate nitrogen and a small amount of suspended solids in the effluent from the short-cut nitrification-anaerobic ammonia oxidation treatment module, so as to ensure that the final effluent meets the discharge standards.

[0099] The above wastewater treatment system effectively integrates the nitrogen and phosphorus removal processes, achieving a compact footprint, low energy consumption, and highly efficient integrated nitrogen removal. An anoxic / aerobic treatment module is placed between the coagulation sedimentation module and the short-cut nitrification-anaerobic ammonia oxidation (SMO) module. This allows for sequential anoxic, aerobic, and sludge-water separation treatment of the effluent from the coagulation sedimentation module. This reduces oxygen consumption during the short-cut nitrification process in the SMO module, lowers system energy consumption, and facilitates control of aeration and dominant bacteria types, improving wastewater treatment stability, especially for cases with high influent COD or nitrate nitrogen concentrations. The combined addition of K3 and polyurethane packing ensures stable synergistic effects between SMO and SMO, guaranteeing rapid biofilm formation in the early stages and stable biofilm formation in the later stages. High treatment efficiency; combined with the vertical rotary drum reactor setup and reasonable speed control during operation, it can achieve zoned attachment and synergistic growth of two functional bacterial groups: short-cut nitrifying bacteria and anaerobic ammonia oxidizing bacteria, which can enhance the shock resistance of the synergistic effect in the wastewater treatment process; fully utilizing the coupling of short-cut nitrification and anaerobic ammonia oxidation significantly reduces the aeration volume and external carbon source requirements; by setting up an aerated biological filter 40 at the end, it can ensure that the system effluent meets the discharge standards stably; through the cooperation of various modules, the overall treatment efficiency can be significantly improved, sludge production can be reduced, and energy consumption and operating costs can be reduced; moreover, the system is highly adaptable to water quality fluctuations. In low environmental conditions or when the influent concentration changes, the system can maintain stability through temperature control devices, adjustment of the reflux ratio, and control of micro-aeration, and is less prone to operational accidents such as sludge bulking or reaction imbalance.

[0100] Example 2

[0101] This embodiment proposes a wastewater treatment method, which specifically uses the wastewater treatment system shown in Embodiment 1 to treat wastewater, thereby verifying the treatment effect of the wastewater treatment system in Embodiment 1.

[0102] The original wastewater had the following characteristics: ammonia nitrogen content of 300 mg / L; total phosphorus content (TP) of 15 mg / L; COD of 1000 mg / L; pH of 7.2 ± 0.2; and temperature of 25 ± 2℃ (under normal atmospheric pressure conditions, without additional pressurization or negative pressure).

[0103] The specific treatment process of this wastewater treatment method is as follows:

[0104] S1. Coagulation sedimentation and phosphorus recovery treatment, including: passing raw wastewater into a coagulation sedimentation reactor and mixing it with a phosphorus removal agent. The phosphorus removal agent used is a 50g / L ferric chloride solution, and the dosage is calculated based on the influent phosphorus concentration. 3+ With PO4 3-The molar ratio is 2:1, and the mixing reaction time can be controlled to 10 minutes. Phosphorus in the wastewater reacts with ferric chloride to form iron-phosphorus flocs. Simultaneously, some undegraded organic matter forms organic flocculent precipitates after coagulation and sedimentation. During this process, approximately 80% or more of the phosphorus, 90% of the iron, and 20% of the organic matter accumulate in the sludge. The reacted wastewater is then passed through a hydrocyclone separator to remove the sludge, including the iron-phosphorus flocs, other large suspended solids, and sediment. The sludge is then fed into the sludge acidification reactor of the phosphorus recovery module for anaerobic acidification and fermentation treatment. The organic matter in the sludge is acidified and hydrolyzed into small-molecule organic compounds such as acetic acid and propionic acid, which can promote the system pH to decrease to around 4 within 3-5 days. Phosphorus... Under acidification, hydrolysis, and biodissimilatory iron reduction, the sludge dissolves and releases ferrous ions into the liquid phase. Simultaneously, ferrous ions are released during the anaerobic acidification fermentation process. Based on the theory of iron and phosphorus flocculation and precipitation, hydrogen peroxide is added to the system to adjust the redox potential (ORP) in the sludge fermentation liquid, oxidizing the ferrous ions released during sludge acidification fermentation into ferric ions. The pH is then adjusted to acidic conditions to react and form ferric phosphate precipitate, which is then separated and recovered. The supernatant from the reaction sedimentation tank is fed into the anoxic tank to fully utilize the VFAs generated and accumulated during the anaerobic acidification fermentation process as a supplementary carbon source for the denitrification stage of the wastewater anoxic tank unit. The effluent from the cyclone sand separator is fed into the anoxic-aerobic treatment module.

[0105] The main reactions within the coagulation sedimentation reactor during the above treatment process 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 includes: the effluent from the hydrocyclone sand separator first enters the anoxic tank of the anoxic-aerobic treatment module, controlling the hydraulic retention time (HRT) of the anoxic tank to be 1.5 h; the dissolved oxygen (DO) concentration is 0.3–0.5 mg / L. In the anoxic tank, the wastewater utilizes the VFAs generated and accumulated during the anaerobic acidification fermentation process of the sludge in the phosphorus recovery module as a supplementary carbon source for the denitrification stage of the anoxic tank, and uses the nitrate nitrogen from the influent or a portion of the nitrate nitrogen from the returned sludge to consume organic matter, achieving partial denitrification, thereby reducing the organic load on the aerobic tank; the wastewater treated in the anoxic tank enters the aerobic tank. The HRT in the aerobic tank is controlled at 2.5h, the DO concentration is 1.5-2.0mg / L, and the aeration air-to-water ratio is approximately 15:1. In the aerobic tank, a portion of the high-concentration organic matter in the wastewater is consumed, and ammonia nitrogen is partially converted into nitrate nitrogen, forming a suitable nitrate / ammonia ratio. This provides conditions for ammonia nitrogen conversion or nitrate nitrogen conversion for subsequent short-cut nitrification-anaerobic ammonium oxidation treatment. The wastewater treated in the aerobic tank enters the secondary sedimentation tank for sludge-water separation treatment. The HRT in the secondary sedimentation tank is controlled at approximately 2h. A portion of the settled sludge is returned to the anoxic tank at a return rate of approximately 50%, and the remaining portion is discharged periodically. The supernatant then flows into the short-cut nitrification-anaerobic ammonium oxidation treatment module.

[0113] S3, Short-cut nitrification-anaerobic ammonium oxidation (PN / A) treatment, includes: effluent from the secondary sedimentation tank first enters the pre-conditioning tank of the short-cut nitrification-anaerobic ammonium oxidation treatment module for flow regulation; then, it is fed into the reaction tank of the reaction module at a specific influent flow rate, and short-cut nitrification and anaerobic ammonium oxidation are simultaneously carried out in an integrated reaction via a vertical rotary drum reactor in the reaction tank; wherein, the carrier packing material filled in the vertical rotary drum reactor is a K3 packing material and polyurethane packing material composition with a volume ratio of 1:1, and the filling rate of the carrier packing material in the vertical rotary drum reactor is approximately 60%; the treated... The process maintains the DO concentration in the reaction module at 0.3–0.6 mg / L, the HRT at 3 h, the pH at 7.0–8.0, and the temperature at approximately 25 ± 2 °C, consistent with the front end. The rotation speed of the rotating drum reactor is controlled at approximately 2 rpm to ensure uniform contact between the carrier packing and the wastewater, while avoiding excessive abrasion of the biofilm. The effluent from the reaction module enters the sedimentation tank, where the HRT is controlled at 4 h. The sedimentation tank collects some of the suspended and non-biofilm-attached sludge from the wastewater, and the effluent then enters the aerated biological filter for further advanced treatment.

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

[0115]

[0116] S4. End-of-pipe deep treatment, including: the effluent from the sedimentation tank enters the biological aerated filter (BAF). The packing material of the biological aerated filter is sintered ceramsite with a particle size of 3-5 mm. The filter bed height is controlled at about 1.0 m, and the DO concentration is controlled at 1.0-2.0 mg / L. The filtration rate is about 6 m / h. Backwashing is performed periodically (about 5-7 days). The wastewater is biochemically treated through the biological aerated filter to remove residual nitrate nitrogen and a small amount of suspended solids in the effluent from the short-cut nitrification-anaerobic ammonium oxidation treatment module.

[0117] Wastewater was treated using the above methods. After the system had been running continuously and stably for 30 days, samples were taken for testing and analysis. Some of the results are shown in Table 1 below:

[0118] Table 1

[0119]

[0120] Note: In Table 1, "—" indicates that no test was conducted or that the results are not comparable; "Removal rate" refers to the overall removal rate of the corresponding pollutants from the influent to the final effluent by the entire process.

[0121] As shown in Table 1 above, the ammonia nitrogen removal rate reached 98.3% through the above wastewater treatment methods, indicating that the wastewater treatment system and methods have good adaptability to high ammonia nitrogen wastewater and can achieve efficient nitrogen removal. The total phosphorus was finally reduced to 1.0 mg / L, achieving a good phosphorus removal effect. The terminal BAF effectively reduced the residual nitrate nitrogen in the PN / A effluent (from 10 mg / L to 2 mg / L), and the effluent could stably meet the standards. Moreover, the entire process system operated stably, without obvious sludge bulking or biofilm clogging problems, and the system could maintain efficient treatment continuously under normal temperature and pressure.

[0122] Example 3

[0123] This embodiment provides a wastewater treatment method. This embodiment adopts a wastewater treatment system similar to that in Embodiment 1. The difference between this wastewater treatment system and that in Embodiment 1 is that the volume ratio of K3 packing and polyurethane packing in the vertical rotary drum reactor of the short-cut nitrification-anaerobic ammonium oxidation treatment module in this embodiment is adjusted from 1:1 in Embodiment 1 to 2:1. The filling rate of the carrier packing is still maintained at 60%. Other aspects are basically the same as the wastewater treatment system in Embodiment 1.

[0124] Furthermore, the specific operation of the wastewater treatment method in this embodiment is basically the same as that in Embodiment 2, with the following differences:

[0125] The original wastewater had the following characteristics: ammonia nitrogen content of approximately 250 mg / L; total phosphorus content (TP) of 10 mg / L; COD of 800 mg / L; pH of 7.0 ± 0.3; and temperature of 20–25℃.

[0126] The main difference in the specific processing procedure is that: in step S1 of this embodiment, the amount of ferric chloride solution added as a phosphorus removal agent is changed from 8 mg Fe in Example 2. 3+ / L adjusted to 5mg Fe 3+ / L; In step S2, the short-cut nitrification-anaerobic ammonia oxidation process, the volume ratio of K3 packing to polyurethane packing in the carrier packing of the vertical rotary reactor in the reaction module is adjusted from 1:1 in Example 2 to 2:1, the carrier packing filling rate remains at 60%, the DO concentration in the reaction module remains at 0.3-0.6 mg / L, and the HRT is shortened from 3 h in Example 2 to 2.5 h. Other treatments (including anoxic tank, aerobic tank, secondary sedimentation tank, BAF, etc.) are operated in roughly the same way as in Example 2, and the retention time can be adjusted as appropriate to adapt to lower influent loads.

[0127] Wastewater was treated using the above methods. After the system had been running continuously and stably for 20 days, samples were taken for testing and analysis. Some of the results are shown in Table 2 below:

[0128] Table 2

[0129]

[0130] Note: In Table 2, "—" indicates that no test was conducted or that the results are not comparable; "Removal rate" refers to the overall removal rate of the corresponding pollutants from the influent to the final effluent by the entire process.

[0131] As shown in Table 2 above, the total phosphorus concentration can still be reduced to below 1 mg / L after wastewater treatment using the above methods, proving that the dosage of phosphorus removal agent (5 mg Fe) can be reduced. 3+ The low influent phosphorus concentration ( / L) still meets the phosphorus removal requirements; furthermore, after the proportion of K3 packing material in the carrier packing material in the vertical rotary drum reactor of the reaction module is increased, the adhesion of ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria to its biofilm is significantly increased, shortening the HRT while maintaining a high ammonia nitrogen removal rate; and the terminal BAF continues to play a role in removing residual nitrate nitrogen, reducing nitrate nitrogen from 12 mg / L to 3 mg / L, so that the effluent meets the discharge standards.

[0132] Example 4

[0133] This embodiment proposes a wastewater treatment method, which is basically the same as the wastewater treatment method in Embodiment 2, with the following differences:

[0134] The original wastewater had the following characteristics: ammonia nitrogen content of approximately 200 mg / L; total phosphorus content (TP) of 8 mg / L; COD of 500 mg / L; pH of 7.2 ± 0.2; and temperature of 10–15℃ (relatively low).

[0135] The main difference in the treatment process is as follows: In this embodiment, both step S2 (anoxic-aerobic treatment) and step S3 (short-cut nitrification-anaerobic ammonium oxidation treatment) activate temperature control devices to maintain the wastewater temperature in the aerobic tank and the reaction module within the range of 30℃ to 35℃. Furthermore, in this embodiment, the HRT in the anoxic-aerobic treatment process is adjusted from 1.5h in Example 2 to 2h, while the DO concentration remains unchanged; and the HRT in the aerobic tank is adjusted from 2.5h in Example 2 to 3h, while the DO concentration remains unchanged. In this embodiment, the DO concentration in the reaction module of the short-cut nitrification-anaerobic ammonium oxidation treatment process is controlled at 0.3–0.5 mg / L, while the HRT remains constant. Additionally, the vertical rotary reactor uses a relatively low rotation speed (1–2 rpm) to reduce the negative impact of slow microbial growth due to low temperature. Other treatment operations are largely the same as in Example 2.

[0136] Wastewater was treated using the above methods. After the system had been running continuously and stably for 25 days, samples were taken for testing and analysis. Some of the results are shown in Table 3.

[0137] Table 3

[0138]

[0139] Note: In Table 3, "—" indicates that no test was conducted or that the results are not comparable; "Removal rate" refers to the overall removal rate of the corresponding pollutants from the influent to the final effluent by the entire process.

[0140] As shown in Table 3 above, wastewater treatment using the above methods, by activating the temperature control system in the wastewater treatment system to maintain the water temperature in the aerobic tank and the reaction tank of the short-cut nitrification-anaerobic ammonia oxidation treatment module at 30-35℃, can maintain the basic activity of the microbial community (including short-cut nitrifying bacteria and anaerobic ammonia oxidizing bacteria), achieving a total ammonia nitrogen removal rate of over 90%. Furthermore, although the growth rate of microorganisms slows down under low temperature conditions, the reaction module of the short-cut nitrification-anaerobic ammonia oxidation treatment module uses a vertical rotating cage reactor and a composite carrier packing filled with K3 packing and polyurethane packing, which can effectively provide bacterial count and biofilm stability, ensuring stable and efficient nitrogen removal. In addition, the terminal BAF can still effectively reduce nitrate nitrogen to 4 mg / L, which can meet general discharge restrictions.

[0141] In summary, the above wastewater treatment systems and methods 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 effluent quality assurance capabilities for wastewater containing nutrients such as ammonia nitrogen and phosphorus, and have broad application prospects and significant economic and environmental benefits.

[0142] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A wastewater treatment system, characterized in that, include: The coagulation and sedimentation module is configured to at least treat wastewater by coagulation and sedimentation to form precipitated sludge and supernatant. A phosphorus recovery module, connected to the coagulation and sedimentation module, is configured to receive the precipitated sludge from the coagulation and sedimentation module and perform phosphorus recovery treatment. The phosphorus recovery module includes a sludge acidification reactor and a reaction sedimentation tank connected to each other. The sludge acidification reactor, connected to the coagulation and sedimentation module, is configured to receive the precipitated sludge from the coagulation and sedimentation module and perform anaerobic acidification fermentation treatment to dissolve and release phosphorus and ferrous ions from the precipitated sludge. The reaction sedimentation tank is configured to perform precipitation reaction and separation and recovery treatment on the phosphorus released from the precipitated sludge. Specifically, the precipitation reaction and separation and recovery treatment on the phosphorus released from the precipitated sludge involves: adding an oxidant to the precipitated sludge to oxidize the ferrous ions released during the anaerobic acidification process into ferric ions, then adjusting the pH of the system to acidic to react and form ferric phosphate precipitate, and finally performing separation and recovery treatment. The anoxic-aerobic treatment module includes an anoxic tank, an aerobic tank, and a secondary sedimentation tank connected in sequence. The anoxic tank is connected to the coagulation and sedimentation module and is configured to receive the supernatant from the coagulation and sedimentation module and perform anoxic treatment to utilize the nitrate nitrogen in the influent to consume organic matter and achieve partial denitrification. A short-cut nitrification-anaerobic ammonia oxidation treatment module includes a reaction module connected to the secondary sedimentation tank; the reaction module is filled with a carrier packing material, which consists only of K3 packing material and polyurethane packing material, and is configured to support at least short-cut nitrifying bacteria and anaerobic ammonia oxidizing bacteria; in the carrier packing material, the mass ratio of K3 packing material to polyurethane packing material is (0.5~2):

1.

2. The wastewater treatment system according to claim 1, characterized in that, The anoxic-aerobic treatment module further 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 influent to the anoxic-aerobic treatment module. The aeration device is linked to the monitoring module and is configured to adjust the aeration rate to the aerobic tank according to the COD concentration and / or nitrate nitrogen content of the influent to the anoxic-aerobic treatment module.

3. The wastewater 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 wastewater treatment system according to claim 1, characterized in that, The coagulation sedimentation module includes a coagulation sedimentation reactor and a sand removal module connected to each other. The sand removal module has an outlet and a sludge discharge outlet. The phosphorus recovery module is connected to the sludge discharge outlet, and the anoxic tank is connected to the outlet.

5. The wastewater treatment system according to claim 1, characterized in that, The reaction module includes at least one reaction unit, which includes a reaction tank and a rotating drum reactor. The rotating drum reactor is located inside the reaction tank, and the carrier packing is filled inside the rotating drum reactor.

6. The wastewater treatment system according to claim 5, characterized in that, The rotary drum reactor is a vertical rotary drum reactor.

7. The wastewater treatment system according to claim 1, characterized in that, The carrier filler has a filling rate of 50% to 75% in the reaction module.

8. The wastewater treatment system according to claim 1, characterized in that, The short-cut nitrification-anaerobic ammonia oxidation treatment module further includes at least one of a pre-conditioning module and a sedimentation tank; the reaction module is connected to the secondary sedimentation tank through the pre-conditioning module; the sedimentation tank is connected to the reaction module; And / or, the wastewater treatment system further 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; and the deoxygenation device is configured to at least deoxygenate the reaction module.

9. The wastewater treatment system according to any one of claims 1 to 8, characterized in that, It also includes an aerated biological filter, which is connected to the short-cut nitrification-anaerobic ammonia oxidation treatment module.

10. A wastewater treatment method, characterized in that, The wastewater treatment system described in any one of claims 1 to 9 is employed, comprising: Wastewater is fed into a coagulation and sedimentation module for coagulation and sedimentation treatment, forming precipitated sludge and supernatant. The precipitated sludge is fed into a phosphorus recovery module for chemical phosphorus recovery treatment. The supernatant is passed into the anoxic and aerobic treatment module and undergoes anoxic treatment, aerobic treatment, and mud-water separation treatment in sequence. Short-cut nitrifying bacteria and anaerobic ammonia oxidation bacteria are loaded onto the carrier packing material in the reaction module of the short-cut nitrification-anaerobic ammonia oxidation treatment module; the wastewater treated by the anoxic-aerobic treatment module is introduced into the short-cut nitrification-anaerobic ammonia oxidation treatment module, and short-cut nitrification and anaerobic ammonia oxidation reactions are carried out in the reaction module.

11. The wastewater treatment method according to claim 10, characterized in that, The wastewater treatment system described in claim 9 is used for implementation; the wastewater treatment method further includes: The wastewater treated by the short-cut nitrification-anaerobic ammonia oxidation treatment module is then fed into an aerated biological filter for further biochemical treatment.

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