Sewage treatment system for treating high-nitrogen wastewater

Abstract

A sewage treatment system for treating high-nitrogen wastewater comprises a pretreatment unit, a denitrification adjusting area, a granular sludge reaction area, a sludge-water separation unit and a water outlet unit which are communicated in sequence, and the sludge-water separation unit is further connected with a sludge discharge unit; the pretreatment unit is used for removing suspended solids and large-particle impurities in the wastewater; the denitrification adjusting area is used for adjusting the dissolved oxygen concentration of the wastewater to enable the proportion of nitrogen in the wastewater to meet the aerobic treatment requirement; the granular sludge reaction zone is used for removing nitrogen and carbon pollutants in the wastewater in a high dissolved oxygen environment and promoting the formation of granular sludge; the sludge-water separation unit is used for separating granular sludge and treated supernate, and returning the separated sludge to the denitrification adjusting area; the sludge discharge unit is used for discharging residual sludge in the system; and the water outlet unit is used for discharging the treated supernate. A denitrification adjusting area is arranged in a sewage treatment system, so that the nitrogen proportion and the dissolved oxygen concentration in wastewater are accurately adjusted, and the operation conditions of a subsequent granular sludge reaction area are optimized.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, and in particular refers to a wastewater treatment system for treating high-nitrogen wastewater. Background Technology

[0002] With increasing emphasis on environmental protection, national requirements for wastewater discharge compliance are constantly rising. However, traditional denitrification processes (such as AO and AAO processes) mainly rely on aerobic flocculent sludge, which performs well in removing ammonia nitrogen but has limited effectiveness in removing total nitrogen. Furthermore, these processes are prone to sludge bulking during operation, leading to decreased system stability and treatment efficiency. In recent years, aerobic granular sludge has gradually become a research hotspot in the wastewater treatment field. This granular sludge, formed by the self-immobilization of various microorganisms, has significant advantages: no need for additional settling tanks, reducing infrastructure investment; low residual sludge discharge; and efficient simultaneous removal of multiple pollutants such as carbon, nitrogen, and phosphorus. Therefore, aerobic granular sludge technology has become a novel biological treatment technology for solving the problems of large footprint and low treatment efficiency in wastewater treatment facilities.

[0003] However, the application of aerobic granular sludge still faces certain technical bottlenecks. For example, when the influent organic load is too high, granular sludge is prone to deflocculation. To maintain granularity, the hydraulic upflow velocity needs to be increased, but this leads to a significant loss of flocculent sludge, thus significantly reducing treatment capacity. Furthermore, when the influent ammonia nitrogen concentration is low but the nitrate nitrogen concentration is high, total nitrogen removal needs to be controlled by reducing the aeration rate. However, reducing the aeration rate may affect the formation and stability of granular sludge. Therefore, the stability and shock resistance of existing aerobic granular sludge technology in high-load wastewater treatment need further optimization. Utility Model Content

[0004] To address the above-mentioned technical problems, the purpose of this utility model is to provide a wastewater treatment system for treating high-nitrogen wastewater. By setting up a denitrification regulation zone in the wastewater treatment system, the nitrogen ratio and dissolved oxygen concentration in the wastewater are precisely adjusted to optimize the operating conditions of the subsequent granular sludge reaction zone. The denitrification regulation zone effectively mitigates the impact of high nitrogen load on the system by dynamically regulating nitrogen form conversion, while creating a suitable environment for the formation of granular sludge. This design fully utilizes the pretreatment and load equalization functions of the denitrification regulation zone, significantly improving the system's denitrification and carbon removal efficiency, simplifying the structure of anaerobic tanks and secondary sedimentation tanks in traditional processes, reducing the footprint and construction costs, and providing an intensive and stable solution for efficient wastewater treatment.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A wastewater treatment system for treating high-nitrogen wastewater.

[0007] It includes a pretreatment unit, a denitrification adjustment zone, a granular sludge reaction zone, a sludge-water separation unit and an effluent unit connected in sequence. The sludge-water separation unit and the denitrification adjustment zone are connected by a reflux connection. The sludge-water separation unit is also connected to a sludge discharge unit.

[0008] The pretreatment unit is used to remove suspended solids and large particulate impurities from the wastewater;

[0009] The denitrification adjustment zone is used to adjust the dissolved oxygen concentration in the wastewater so that the nitrogen ratio in the wastewater is adapted to the requirements of aerobic treatment.

[0010] The granular sludge reaction zone is used to remove nitrogen and carbon pollutants from wastewater and promote the formation of granular sludge in a high dissolved oxygen environment.

[0011] The sludge-water separation unit is used to separate granular sludge and treated supernatant, and to return the separated sludge to the denitrification adjustment zone;

[0012] The sludge discharge unit is used to discharge excess sludge from the system.

[0013] The effluent unit is used to discharge the treated supernatant.

[0014] In some technical solutions, the pretreatment unit includes a bar screen and a sedimentation tank, used to remove large suspended solids and settling particles respectively, and the bar screen is in fluid communication with the sedimentation tank.

[0015] In some technical solutions, the denitrification adjustment zone adjusts the dissolved oxygen concentration through a dissolved oxygen control device. The dissolved oxygen control device includes a dissolved oxygen detector and an aeration pipe regulating valve interlocked with it, which is used to dynamically adjust the aeration rate according to the ratio of ammonia nitrogen to nitrate nitrogen in the wastewater.

[0016] In some technical solutions, the granular sludge reaction zone includes a high-efficiency aeration device and a dissolved oxygen meter. The dissolved oxygen meter is used to monitor the dissolved oxygen concentration in the granular sludge reaction zone in real time, and the high-efficiency aeration device is used to form uniform bubbles in the wastewater to provide a high dissolved oxygen environment.

[0017] In some technical solutions, the high-efficiency aeration device includes a blower and a microbubble aeration system.

[0018] The blower is used to provide a stable airflow source and adjust the airflow intensity according to the dissolved oxygen demand in the granular sludge reaction zone.

[0019] The microbubble aeration system disperses the airflow provided by the blower into tiny bubbles, thereby improving oxygen transfer efficiency, maintaining the suspended state of granular sludge, and promoting aerobic reactions and the formation of granular sludge.

[0020] In some technical solutions, the sludge-water separation unit is a three-phase separator. The three-phase separator achieves sludge-water separation through gravity sedimentation, and the separated sludge is transported to the denitrification adjustment zone through a reflux device. The separated supernatant is discharged through the effluent unit.

[0021] In some technical solutions, the reflux device includes a sludge reflux pump, which is used to mix the flocculent sludge separated from the sludge-water separation unit with the influent and then transport it to the denitrification adjustment zone to improve nitrogen conversion efficiency.

[0022] In some technical solutions, the sludge discharge unit includes a residual sludge discharge pipe, which is connected to a sludge-water separation unit and is used to dynamically adjust the sludge discharge volume to maintain the sludge concentration in the system.

[0023] In some technical solutions, the denitrification adjustment zone and the granular sludge reaction zone are connected via a water inlet; and / or,

[0024] A feed pump is provided between the pretreatment unit and the denitrification adjustment zone. The feed pump is used to transport the pretreated wastewater to the denitrification adjustment zone at a controllable flow rate.

[0025] In some technical solutions, the wastewater treatment system is suitable for treating high-concentration organic wastewater and high-nitrogen wastewater, and can simultaneously remove carbon, nitrogen and phosphorus pollutants from the wastewater.

[0026] The present invention, by adopting the above technical solution, has at least the following beneficial effects:

[0027] 1. The pre-denitrification adjustment zone in this invention precisely adjusts the ratio of ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen in wastewater by controlling the dissolved oxygen concentration, so that the concentration of different forms of nitrogen meets the reaction requirements of subsequent aerobic granular sludge treatment. This function avoids the complex operation of directly adjusting the aeration rate to regulate nitrogen in the granular sludge reaction zone, ensuring the stability of high aeration conditions, which is conducive to the rapid formation and stable operation of aerobic granular sludge. By optimizing the nitrogen ratio through the pre-denitrification low aeration zone, not only is the formation efficiency of granular sludge improved, but the system's treatment capacity is also reduced due to fluctuations in reaction conditions.

[0028] 2. In this invention, the denitrification adjustment zone can handle part of the pollution load in high-concentration wastewater, while the introduction of circulating water dilutes the influent concentration, effectively reducing the load impact on the system. This pretreatment function significantly improves the system's adaptability to high-concentration organic wastewater and nitrogen load fluctuations, reduces the burden on the granular sludge reaction zone, and extends the system's operating cycle. In addition, the diluted and partially treated wastewater enters the subsequent treatment zone more evenly, ensuring that the entire system maintains stable and efficient operation under high load conditions.

[0029] 3. In this invention, the flocculent sludge gradually completes the domestication and optimization of microbial strains through long-term circulation and adaptation to the wastewater environment within the system. Under conditions of high aeration and high upward flow velocity, the microorganisms in the flocculent sludge gradually transform into structurally stable aerobic granular sludge through secretion of extracellular polymers (EPS) and self-immobilization. This mechanism fully utilizes the dynamic circulation capacity of the system, transforming the originally loose flocculent sludge into granular sludge with good settling performance and strong shock resistance, which not only improves the sludge treatment efficiency but also realizes the recycling of resources.

[0030] 4. This invention replaces the anaerobic tank and secondary sedimentation tank in traditional processes by integrating the functions of the denitrification adjustment zone and the granular sludge reaction zone. This design significantly reduces the system's land requirements and construction costs, while simplifying the process flow and reducing reliance on civil engineering. Through a highly efficient sludge-water separation device and a reflux system, this invention can achieve efficient sludge-water separation while maintaining the stability and efficiency of system operation, providing a more economical and intensive solution for wastewater treatment facilities. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings and their markings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the wastewater treatment system for treating high-nitrogen wastewater according to one embodiment of the present invention.

[0033] The meanings of the symbols marked in the figure are as follows:

[0034] 1—Pretreatment unit, 2—Feed pump, 3—Sludge return pump, 4—Denitrification adjustment zone, 5—Dissolved oxygen detector, 6—Aeration pipe regulating valve, 7—Granular sludge reaction zone, 8—Dissolved oxygen meter, 9—Three-phase separator, 10—Excess sludge discharge pipe, 11—Water outlet pipe, 12—Blower, 13—Water outlet. Detailed Implementation

[0035] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the specific implementation methods of this utility model will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of this utility model. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0036] To keep the drawings concise, each figure only schematically shows the parts relevant to the utility model, and these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some figures, only one of the components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0037] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0038] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0039] like Figure 1 A preferred embodiment of the wastewater treatment system for treating high-nitrogen wastewater according to this utility model includes a pretreatment unit 1, a denitrification adjustment zone 4, a granular sludge reaction zone 7, a sludge-water separation unit, and an effluent unit connected in sequence. The sludge-water separation unit and the denitrification adjustment zone 4 are connected via a reflux connection, and the sludge-water separation unit is also connected to a sludge discharge unit. The composition and function of each process are described in detail below:

[0040] Pretreatment unit 1 is primarily used to remove suspended solids and large particulate impurities from wastewater. Specifically, it may include a bar screen and a grit chamber, which are fluidly connected. The bar screen effectively intercepts large suspended solids, protecting downstream equipment from clogging and damage caused by particles. The grit chamber separates heavier settling particles, reducing the load on subsequent treatment units and preventing excessively high sludge concentrations from adversely affecting denitrification and the formation of granular sludge. This preliminary treatment ensures the efficient operation of subsequent units in the system and extends the service life of the equipment.

[0041] The denitrification adjustment zone 4 is used to adjust the dissolved oxygen concentration in the wastewater to match the nitrogen ratio in the wastewater with the requirements of aerobic treatment. Specifically, the denitrification adjustment zone 4 regulates the dissolved oxygen concentration through a dissolved oxygen control device, which includes a dissolved oxygen detector 5 and an aeration pipe regulating valve 6 interlocked with it. The dissolved oxygen detector 5 monitors the concentrations of ammonia nitrogen and nitrate nitrogen in the wastewater in real time, and the aeration pipe regulating valve 6 dynamically adjusts the aeration rate based on the monitoring results to control the dissolved oxygen concentration and ensure the nitrogen ratio matches the requirements of aerobic treatment. Through the pre-treatment function of the denitrification adjustment zone 4, the nitrogen concentration and form of the wastewater before entering the granular sludge reaction zone 7 are effectively optimized, thereby reducing the impact on subsequent treatment units, ensuring the stable formation of granular sludge, and improving the overall denitrification efficiency of the system.

[0042] The granular sludge reaction zone 7 is used to remove nitrogen and carbon pollutants from wastewater and promote the formation of granular sludge in a high dissolved oxygen environment. Specifically, the granular sludge reaction zone 7 includes a high-efficiency aeration device and a dissolved oxygen meter 8. The dissolved oxygen meter 8 is used to monitor the dissolved oxygen concentration in the granular sludge reaction zone 7 in real time to ensure that the oxygen environment in the reaction zone meets the requirements for granular sludge formation. The high-efficiency aeration device is used to form uniform bubbles in the wastewater to provide a high dissolved oxygen environment. Preferably, the high-efficiency aeration device provides a stable airflow source through a blower 12 and, in conjunction with a microbubble aeration system, disperses the airflow into tiny bubbles, significantly improving oxygen transfer efficiency while maintaining the suspended state of the granular sludge, promoting aerobic reaction and granular sludge formation. The granular sludge reaction zone 7 not only achieves efficient removal of pollutants but also accelerates the sludge granulation process through continuous high dissolved oxygen conditions, resulting in granular sludge with good settling performance and shock resistance.

[0043] The sludge-water separation unit separates granular sludge from the treated supernatant, and returns the separated sludge to the denitrification adjustment zone 4. Specifically, the sludge-water separation unit is a three-phase separator 9, which achieves sludge-water separation through gravity sedimentation. The separated sludge is then transported to the denitrification adjustment zone 4 via a return device, while the separated supernatant is discharged through the effluent unit. Preferably, the return device includes a sludge return pump 3, which mixes the flocculent sludge separated from the sludge-water separation unit with the influent and then transports it to the denitrification adjustment zone 4 to improve nitrogen conversion efficiency. The design of the three-phase separator 9 here reduces the floor space required by traditional sedimentation tanks while significantly improving sludge-water separation efficiency, ensuring stable system operation.

[0044] The sludge discharge unit is used to discharge excess sludge from the system; specifically, it includes an excess sludge discharge pipe 10, which is connected to the sludge-water separation unit and is used to dynamically adjust the sludge discharge rate to maintain the sludge concentration in the system. By discharging aged sludge in a timely manner, excessive sludge load is avoided, which could lead to a decrease in system efficiency, while ensuring that newly formed granular sludge can maintain good activity and stability.

[0045] The effluent unit is used to discharge the treated supernatant, including an effluent pipe 11, which is connected to the mud-water separation unit, specifically, to the upper part of the three-phase separator 9. The design is able to meet the requirements for stable effluent discharge.

[0046] The system optimizes the nitrogen ratio in the influent through the pre-denitrification adjustment zone 4, which greatly improves the operating efficiency of the granular sludge reaction zone 7. Furthermore, the three-phase separator 9 replaces the traditional secondary sedimentation tank, significantly reducing the footprint and construction costs.

[0047] In some specific implementations, to adapt to fluctuations in the influent load, a feed pump 2 is added between the pretreatment unit 1 and the denitrification adjustment zone 4. The feed pump 2 dynamically adjusts the flow rate and pressure of the transported wastewater based on real-time monitoring results of the influent flow rate and water quality. When the influent concentration is high, the feed pump 2 reduces the flow rate, extending the treatment time in the denitrification adjustment zone 4 and effectively reducing the pollution load entering the granular sludge reaction zone 7. When the influent concentration is low, the feed pump 2 increases the flow rate, ensuring a dynamic match between treatment efficiency and treatment capacity. The introduction of the feed pump 2 further enhances the system's resistance to shock loads and ensures stable operation of the entire treatment system under different load conditions.

[0048] In some specific implementations, the denitrification adjustment zone 4 and the granular sludge reaction zone 7 are fluidly connected through a water inlet 13. The water inlet 13 is designed with a liquid level regulation function to ensure that the wastewater treated in the denitrification adjustment zone 4 can flow smoothly and evenly into the granular sludge reaction zone 7.

[0049] This application designs an integrated wastewater treatment system comprising a pretreatment unit 1, a denitrification adjustment zone 4, a granular sludge reaction zone 7, a sludge-water separation unit, and a sludge discharge unit. This system precisely controls the nitrogen content in wastewater, efficiently forms aerobic granular sludge, and ensures stable operation. The denitrification adjustment zone 4, as the core functional unit, dynamically adjusts the dissolved oxygen concentration to optimize the ratio of ammonia nitrogen to nitrate nitrogen in the wastewater, ensuring that the wastewater entering the granular sludge reaction zone 7 has suitable nitrogen forms, significantly improving the system's denitrification efficiency and shock resistance. The system as a whole simplifies the traditional anaerobic tank and secondary sedimentation tank through low-energy level difference drive, efficient sludge-water separation by the three-phase separator 9, and a sludge return mechanism. This reduces the footprint and construction costs, ensures the stability and adaptability of treatment efficiency, and provides a reliable environmental protection solution for municipal and industrial sectors.

[0050] A wastewater treatment method for treating high-nitrogen wastewater according to a preferred embodiment of the present invention includes the following steps:

[0051] After the wastewater passes through the pretreatment unit 1 to remove large particulate suspended solids and impurities, it is transported to the denitrification adjustment zone 4 by the feed pump 2.

[0052] Within the denitrification adjustment zone 4, the aeration rate is adjusted to mix the wastewater with the flocculent sludge and induce a denitrification reaction. The aeration rate is monitored and interlocked in real time by the dissolved oxygen detector 5 in the denitrification adjustment zone 4.

[0053] Wastewater treated in denitrification adjustment zone 4 is transported to granular sludge reaction zone 7. In granular sludge reaction zone 7, the high dissolved oxygen environment promotes the formation of granular sludge, while further removing ammonia nitrogen and total nitrogen from the wastewater.

[0054] Sludge and water are separated by a three-phase separator 9 installed in the granular sludge reaction zone 7. The supernatant is discharged through the effluent pipe 11, and the flocculent sludge is returned to the denitrification adjustment zone 4 through the sludge return pump 3.

[0055] The excess sludge generated by the system is discharged through the excess sludge discharge pipe 10 to maintain the stability of the sludge concentration in the system.

[0056] This method effectively integrates denitrification, carbon removal, and sludge-water separation functions, possessing high-efficiency treatment capacity, good resistance to load shocks, and significant energy-saving advantages. The effluent quality is stable and meets standards, making it suitable for the treatment needs of municipal and industrial wastewater.

[0057] The above-described embodiments are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the appended claims.

Claims

1. A wastewater treatment system for treating high-nitrogen wastewater, characterized in that, It includes a pretreatment unit, a denitrification adjustment zone, a granular sludge reaction zone, a sludge-water separation unit and an effluent unit connected in sequence. The sludge-water separation unit and the denitrification adjustment zone are connected by a reflux connection. The sludge-water separation unit is also connected to a sludge discharge unit. The pretreatment unit is used to remove suspended solids and large particulate impurities from the wastewater; The denitrification adjustment zone is used to adjust the dissolved oxygen concentration in the wastewater so that the nitrogen ratio in the wastewater is adapted to the requirements of aerobic treatment. The granular sludge reaction zone is used to remove nitrogen and carbon pollutants from wastewater and promote the formation of granular sludge in a high dissolved oxygen environment. The sludge-water separation unit is used to separate granular sludge and treated supernatant, and to return the separated sludge to the denitrification adjustment zone; The sludge discharge unit is used to discharge excess sludge from the system. The effluent unit is used to discharge the treated supernatant.

2. The wastewater treatment system according to claim 1, characterized in that, The pretreatment unit includes a screen and a sedimentation tank, used to remove large suspended solids and settling particles respectively, and the screen is in fluid communication with the sedimentation tank.

3. The wastewater treatment system according to claim 1, characterized in that, The denitrification adjustment zone regulates the dissolved oxygen concentration through a dissolved oxygen control device, which includes a dissolved oxygen detector and an aeration pipe regulating valve interlocked with it, and is used to dynamically adjust the aeration rate according to the ratio of ammonia nitrogen to nitrate nitrogen in the wastewater.

4. The wastewater treatment system according to claim 1, characterized in that, The granular sludge reaction zone includes a high-efficiency aeration device and a dissolved oxygen meter. The dissolved oxygen meter is used to monitor the dissolved oxygen concentration in the granular sludge reaction zone in real time, and the high-efficiency aeration device is used to form uniform bubbles in the wastewater to provide a high dissolved oxygen environment.

5. The wastewater treatment system according to claim 4, characterized in that, The high-efficiency aeration device includes a blower and a microbubble aeration system. The blower is used to provide a stable airflow source and adjust the airflow intensity according to the dissolved oxygen demand in the granular sludge reaction zone. The microbubble aeration system disperses the airflow provided by the blower into tiny bubbles, thereby improving oxygen transfer efficiency, maintaining the suspended state of granular sludge, and promoting aerobic reactions and the formation of granular sludge.

6. The wastewater treatment system according to claim 1, characterized in that, The mud-water separation unit is a three-phase separator. The three-phase separator achieves mud-water separation through gravity sedimentation, and the separated sludge is transported to the denitrification adjustment zone through a reflux device. The separated supernatant is discharged through the effluent unit.

7. The wastewater treatment system according to claim 6, characterized in that, The reflux device includes a sludge reflux pump, which is used to mix the flocculent sludge separated from the sludge-water separation unit with the influent and then transport it to the denitrification adjustment zone to improve nitrogen conversion efficiency.

8. The wastewater treatment system according to claim 1, characterized in that, The sludge discharge unit includes a residual sludge discharge pipe, which is connected to a sludge-water separation unit and is used to dynamically adjust the sludge discharge volume to maintain the sludge concentration in the system.

9. The wastewater treatment system according to claim 1, characterized in that, The denitrification adjustment zone and the granular sludge reaction zone are connected via a water inlet; and / or, A feed pump is provided between the pretreatment unit and the denitrification adjustment zone. The feed pump is used to transport the pretreated wastewater to the denitrification adjustment zone at a controllable flow rate.

10. The wastewater treatment system according to claim 1, characterized in that, The wastewater treatment system is suitable for treating high-concentration organic wastewater and high-nitrogen wastewater, and can simultaneously remove carbon, nitrogen and phosphorus pollutants from the wastewater.

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