Wastewater treatment system and method

Abstract

The present application relates to wastewater treatment technical field, disclose wastewater treatment system and method, wastewater treatment system includes biogas slurry storage pool, filtrate storage pool, hydrolysis acidification tank, first aeration assembly, SBR reaction tank, second aeration assembly and control component, biogas slurry storage pool and filtrate storage pool are connected with hydrolysis acidification tank, and biogas slurry storage pool is equipped with biogas slurry inlet pump between hydrolysis acidification tank, biogas slurry storage pool is equipped with filtrate inlet pump between hydrolysis acidification tank, first aeration assembly is connected with hydrolysis acidification tank and is suitable for inputting trace aeration, control component is connected with biogas slurry inlet pump and filtrate inlet pump signal, SBR reaction tank is connected with hydrolysis acidification tank, second aeration assembly is connected with SBR reaction tank, the present application controls biogas slurry inlet pump and filtrate inlet pump flow by control component, guarantees better carbon nitrogen ratio, through combined processing, the carbon nitrogen balance required for denitrification can be realized, so as to stabilize biological reaction system pH, improve nitrogen removal efficiency and reduce the dependence on additional carbon source and alkali agent.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more specifically to wastewater treatment systems and methods. Background Technology

[0002] Livestock and poultry farming wastewater is widely recognized as a typical high-concentration organic wastewater due to its large volume, high organic matter concentration, and rich nitrogen and phosphorus content. Direct discharge without effective treatment not only causes severe eutrophication of water bodies but also generates foul odor pollution, impacting the surrounding environment. Therefore, the efficient treatment of livestock and poultry farming wastewater has always been a key focus of research and engineering practice in the field of environmental engineering. Currently, the most commonly used treatment route in engineering is the combined anaerobic and aerobic process for treating livestock and poultry farming wastewater.

[0003] However, in the treatment of digestate produced from anaerobic digestion of livestock and poultry wastewater, the biogas slurry has already consumed a large amount of organic matter during the anaerobic digestion stage, resulting in a significant decrease in the carbon-to-nitrogen ratio. Upon entering the aerobic treatment stage, due to the lack of sufficient organic carbon source, the denitrification process cannot proceed smoothly, leading to the inability to effectively replenish the alkalinity consumed during nitrification. As a result, the pH of the reaction system continuously decreases. When the pH falls below 7.0, the activity of nitrifying bacteria is significantly inhibited, the nitrification rate decreases drastically, and the ammonia nitrogen removal rate drops significantly, sometimes even leading to system collapse. The low carbon-to-nitrogen ratio of biogas slurry makes its aerobic treatment stage more prone to problems such as low nitrogen removal efficiency and operational instability.

[0004] To address the aforementioned issues, existing technologies primarily employ two approaches. One is to supplement the biogas slurry with external carbon sources, such as sodium acetate, glucose, and ethanol, before it enters the aerobic reactor or during operation to enhance denitrification. The other is to add alkalinity regulators, such as sodium carbonate and sodium hydroxide, to counteract the alkalinity consumed during nitrification. While these measures improve the operating conditions of aerobic biogas slurry treatment to some extent, they also introduce new drawbacks. External carbon sources are expensive, significantly increasing operating costs, and their utilization rate is limited; some carbon sources cannot be effectively utilized by denitrifying microorganisms, resulting in waste. Improper dosing control can also lead to increased COD in the effluent. While chemical alkali supplementation can buffer pH, it increases chemical reagent costs, enhances system dependence, and raises potential secondary salt pollution issues. Furthermore, both carbon and alkali supplementation require additional dosing systems and operational management, significantly increasing operational complexity and hindering the stable operation and widespread adoption of large-scale projects.

[0005] In summary, existing biogas slurry treatment processes still suffer from problems such as insufficient denitrification capacity, severe pH drop, inhibited nitrification process, low nitrogen removal efficiency, and high dependence on external reagents when dealing with the low carbon-to-nitrogen ratio of anaerobic digester slurry. These problems lead to poor operational economy and insufficient stability, which restricts the further promotion and application of biogas slurry treatment processes. Summary of the Invention

[0006] This invention provides a wastewater treatment system and method to solve the problems in the existing technology of livestock and poultry breeding wastewater treatment, such as insufficient denitrification capacity, severe pH drop, inhibited nitrification process, low nitrogen removal efficiency, and high dependence on external agents.

[0007] In a first aspect, the present invention provides a wastewater treatment system, comprising a biogas slurry storage tank, a filtrate storage tank, a hydrolysis acidification tank, a first aeration component, an SBR reactor, a second aeration component, and a control component. The biogas slurry storage tank is suitable for holding biogas slurry, the filtrate storage tank is suitable for holding filtrate, the biogas slurry storage tank and the filtrate storage tank are connected to the hydrolysis acidification tank, a biogas slurry inlet pump is provided between the biogas slurry storage tank and the hydrolysis acidification tank, a filtrate inlet pump is provided between the filtrate storage tank and the hydrolysis acidification tank, the first aeration component is connected to the hydrolysis acidification tank and is suitable for inputting a small amount of aeration into the hydrolysis acidification tank, the SBR reactor is connected to the hydrolysis acidification tank and is suitable for cultivating aerobic granular sludge, the second aeration component is connected to the SBR reactor, and the control component is signal-connected to the biogas slurry inlet pump and the filtrate inlet pump.

[0008] Beneficial effects: This invention controls the flow rates of the biogas slurry influent pump and the filtrate influent pump through a regulating component, ensuring a good carbon-nitrogen ratio. Combined treatment achieves the carbon-nitrogen balance required for denitrification, thereby stabilizing the pH of the biological reaction system, improving nitrogen removal efficiency, and reducing dependence on external carbon sources and alkalis. Micro-aeration improves the mixing effect in the hydrolysis acidification tank, prevents bottom sedimentation and local dead zones, and maintains the balance of the microbial community. It also creates a micro-aerobic environment to promote the hydrolysis of large organic molecules while avoiding excessive consumption of small organic molecules, maximizing the accumulation of small-molecule degradable carbon sources in the tank. Furthermore, it inhibits methanogenesis, which is beneficial for the accumulation of small-molecule degradable organic matter, allowing more organic carbon sources to be used in the subsequent denitrification process, thus improving the overall nitrogen removal efficiency of the system.

[0009] In one alternative embodiment, the wastewater treatment system further includes an intermediate water tank, which is disposed between the hydrolysis acidification tank and the SBR reaction tank, and the control components are disposed in the intermediate water tank.

[0010] Beneficial effects: The intermediate water tank of this invention can adjust the water flow, buffer water quality fluctuations, and serve as an interface for water quality monitoring and control. The control components can supplement the mixed liquor in the intermediate water tank with an external carbon source to ensure sufficient denitrification conditions.

[0011] In one optional embodiment, the control component includes a carbon replenishment device, a first detector, a second detector, and a first controller. The first detector is disposed in an intermediate water tank and is adapted to detect the concentration of degradable organic matter. The second detector is disposed in the intermediate water tank and is adapted to detect the total nitrogen concentration. The first controller is signal-connected to the first detector, the second detector, and the carbon replenishment device.

[0012] Beneficial effects: The present invention obtains the concentration of degradable organic matter by the first detector and the total nitrogen concentration by the second detector. The first controller can control the carbon supplementation device to achieve dynamic optimization of the mixing ratio of biogas slurry and filtrate and self-sufficiency balance of denitrification carbon source. Without the need for a large amount of external reagents, it can significantly improve nitrogen removal efficiency, reduce operating costs, and adapt to the treatment environment of livestock and poultry wastewater with large fluctuations in water quality.

[0013] In one optional embodiment, the hydrolysis acidification tank includes a first tank body, a first stirrer, and a third detector. The first stirrer is disposed in the first tank body, the third detector is disposed in the first tank body, and the third detector is signal-connected to the first aeration component.

[0014] Beneficial effects: In this invention, the first stirrer ensures thorough mixing of water and microorganisms in the hydrolysis acidification tank, resulting in uniform distribution of biogas slurry, filtrate, and incoming nutrients. This improves the degradation efficiency of the hydrolysis acidification microorganisms and prevents sedimentation or dead zones. The third detector monitors dissolved oxygen in the hydrolysis acidification tank in real time, providing control data for the operation of the first aeration component.

[0015] In one optional embodiment, the first aeration assembly includes a first air pump, a first aeration disc, and a second controller. The first aeration disc is disposed in the first tank body, and the second controller is connected to the first air pump and the first aeration disc. The second controller is also signal-connected to a third detector.

[0016] Beneficial effects: The present invention can adjust the dissolved oxygen concentration in the hydrolysis acidification tank by connecting the second controller with the third detector signal, so as to avoid inhibiting the activity of absolute anaerobic microorganisms.

[0017] In one optional embodiment, the SBR reactor includes a second tank body, a second stirrer, and a fourth detector. The second stirrer is disposed in the second tank body, the fourth detector is disposed in the second tank body, and the fourth detector is signal-connected to the second aeration assembly.

[0018] Beneficial effects: In this invention, the second agitator ensures thorough mixing of water and microorganisms during the initial stages of filling or aeration, resulting in uniform distribution of organic matter and nitrogen in the influent, preventing sedimentation or dead zones, and improving biological reaction efficiency. The fourth detector can monitor the dissolved oxygen concentration in the SBR reactor in real time, providing a control basis for the operation of the second aeration component.

[0019] In one optional embodiment, the second aeration assembly includes a second air pump, a second aeration disc, and a third controller. The second aeration disc is disposed in the second tank body, the third controller is connected to the second air pump and the second aeration disc, and the third controller is signal-connected to a fourth detector.

[0020] Beneficial effects: The third controller of this invention can automatically adjust the aeration intensity of the air pump according to the dissolved oxygen concentration obtained by the fourth detector, so as to maintain the dissolved oxygen in the water within a suitable range, ensure the activity of nitrifying bacteria and aerobic microorganisms, and promote the degradation of organic matter and the ammonia nitrogen nitrification process.

[0021] In one optional embodiment, the wastewater treatment system further includes a first separator and a second separator, the first separator being connected to a biogas slurry storage tank and a filtrate storage tank, and the second separator being connected to the first separator and a hydrolysis acidification tank.

[0022] Beneficial effects: In this invention, both the biogas slurry and the filtrate are pretreated by the first separator and the second separator, which can remove large particulate suspended solids, oils and colloids, and protect the stable operation of the subsequent biological treatment unit.

[0023] Secondly, the present invention also provides a wastewater treatment method, which uses the above-mentioned wastewater treatment system and includes the following steps:

[0024] The biogas slurry in the biogas slurry storage tank and the filtrate in the filtrate storage tank are mixed in proportion and then fed into the hydrolysis acidification tank.

[0025] Start the first agitator and start the first aeration component to input a small amount of aeration into the hydrolysis acidification tank;

[0026] To obtain the dissolved oxygen concentration in the water body of the hydrolysis acidification tank;

[0027] Adjust the aeration rate of the first aeration component according to the dissolved oxygen concentration in the water in the hydrolysis acidification tank.

[0028] The water in the hydrolysis acidification tank is transferred into the intermediate water tank;

[0029] To obtain the concentrations of biodegradable organic matter and total nitrogen in the intermediate water tank;

[0030] Adjust the carbon-nitrogen ratio of the water in the intermediate pool;

[0031] The water in the intermediate water tank is fed into the SBR reactor.

[0032] Obtain the dissolved oxygen concentration in the water of the SBR reactor;

[0033] Adjust the aeration rate of the second aeration component according to the dissolved oxygen concentration in the SBR reactor.

[0034] Beneficial effects: Compared with traditional anaerobic processes, this invention achieves an improved hydrolysis acidification mode that balances mixture optimization, maintenance of microbial activity, and carbon source retention. Through this method, the hydrolysis acidification tank can efficiently and stably hydrolyze organic matter, providing suitable water quality for subsequent aerobic reactions, while simultaneously enhancing the available carbon source required for denitrification and improving the overall system treatment efficiency.

[0035] In one optional implementation, the step of adjusting the carbon-to-nitrogen ratio of the water in the intermediate tank includes:

[0036] Based on the concentration of degradable organic matter and total nitrogen in the intermediate water tank, the carbon-nitrogen ratio of the water is calculated in real time and compared with the preset target ratio.

[0037] If the carbon-to-nitrogen ratio meets or exceeds the target value, the system maintains the current mixing ratio of biogas slurry and filtrate;

[0038] If the carbon-nitrogen ratio is lower than the target value, adjust the flow rate of biogas slurry and filtrate into the hydrolysis acidification tank;

[0039] If the preset target ratio still cannot be met after adjusting the ratio, start the carbon replenishment device to replenish carbon to the intermediate water tank.

[0040] Beneficial effects: By adjusting the carbon supplementation device, this invention can achieve dynamic optimization of the mixing ratio of biogas slurry and filtrate, and self-sufficiency balance of denitrification carbon source. Without the need for a large amount of external reagents, it can significantly improve nitrogen removal efficiency, reduce operating costs, and adapt to the treatment environment of livestock and poultry wastewater with large fluctuations in water quality. Attached Figure Description

[0041] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of a wastewater treatment system according to an embodiment of the present invention;

[0043] Figure 2 This is a schematic flowchart of a wastewater treatment method according to an embodiment of the present invention.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. Biogas slurry storage tank; 11. Biogas slurry inlet pump;

[0046] 2. Filtrate storage tank; 21. Filtrate inlet pump;

[0047] 3. Hydrolysis acidification tank; 31. First tank body; 32. First stirrer; 33. Third detector;

[0048] 4. First aeration component; 41. First air pump; 42. First aeration disc; 43. Second controller;

[0049] 5. SBR reactor; 51. Second tank body; 52. Second stirrer; 53. Fourth detector; 54. Reactor inlet pump;

[0050] 6. Second aeration component; 61. Second air pump; 62. Second aeration disc; 63. Third controller;

[0051] 7. Intermediate water tank;

[0052] 8. Control components; 81. Carbon replenishment device; 82. First detector; 83. Second detector; 84. First controller;

[0053] 9. First separator; 10. Second separator. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] The following is combined with Figures 1 to 2 The following describes embodiments of the present invention.

[0056] According to embodiments of the present invention, in one aspect, such as Figure 1 As shown, a wastewater treatment system is provided, including a biogas slurry storage tank 1, a filtrate storage tank 2, a hydrolysis acidification tank 3, a first aeration component 4, an SBR reactor 5, a second aeration component 6, and a control component 8. The biogas slurry storage tank 1 is suitable for holding biogas slurry, and the filtrate storage tank 2 is suitable for holding filtrate. The biogas slurry storage tank 1 and the filtrate storage tank 2 are connected to the hydrolysis acidification tank 3. A biogas slurry inlet pump 11 is provided between the biogas slurry storage tank 1 and the hydrolysis acidification tank 3, and a filtrate inlet pump 21 is provided between the filtrate storage tank 2 and the hydrolysis acidification tank 3. The first aeration component 4 is connected to the hydrolysis acidification tank 3 and is suitable for inputting a small amount of aeration into the hydrolysis acidification tank 3. The SBR reactor 5 is connected to the hydrolysis acidification tank 3 and is suitable for cultivating aerobic granular sludge. The second aeration component 6 is connected to the SBR reactor 5, and the control component 8 is signal-connected to the biogas slurry inlet pump 11 and the filtrate inlet pump 21.

[0057] Specifically, in this embodiment, the biogas slurry storage tank 1 contains biogas slurry, which is the anaerobic digestion liquid of livestock and poultry wastewater after anaerobic digestion. Its main characteristics are high ammonia nitrogen concentration, low content of degradable organic carbon, low carbon-to-nitrogen ratio, unstable pH and alkalinity, and it also contains some residual volatile fatty acids, dissolved inorganic salts, and trace microbial communities. The filtrate storage tank 2 contains filtrate, which is the liquid discharged after solid-liquid separation (such as pressure filtration or centrifugal dewatering) of livestock and poultry wastewater. Its main characteristics are a high proportion of degradable organic carbon, some dissolved nitrogen and phosphorus, colloidal substances in the water, suspended microparticles, and a small amount of oil. Both biogas slurry and filtrate contain COD and ammonia nitrogen, which are the main target pollutants. The COD / ammonia nitrogen ratio in biogas slurry is low, which is not conducive to denitrification, while the COD / ammonia nitrogen ratio in filtrate is high. Mixing the two can increase the COD / ammonia nitrogen ratio, which is beneficial to denitrification. By mixing biogas slurry and filtrate, the carbon and nitrogen balance required for denitrification can be achieved, thereby stabilizing the pH of the biological reaction system, improving nitrogen removal efficiency, and reducing dependence on external carbon sources and alkali agents.

[0058] In this embodiment, the biogas slurry and filtrate can be mixed in a specific ratio in the hydrolysis acidification tank 3, or they can be mixed in a specific ratio before being introduced into the hydrolysis acidification tank 3. The first aeration component 4 is used to supply a trace amount of gas to the mixture in the hydrolysis acidification tank 3 to achieve auxiliary aeration. Hydrolyzing bacteria and acidifying bacteria are added to the hydrolysis acidification tank 3. The hydrolyzing bacteria and acidifying bacteria hydrolyze the insoluble organic matter in the mixture into soluble organic matter, and convert the large molecules that are difficult to biodegrade into small molecules that are easy to biodegrade, thereby improving the biodegradability of the mixture and providing a good water quality environment for subsequent biochemical treatment.

[0059] In this embodiment, the abundant biodegradable organic matter in the filtrate is used as a carbon source for denitrification, achieving self-sufficiency in denitrification and reducing reliance on external reagents. The filtrate and biogas slurry are mixed in a specific ratio and introduced into the hydrolysis acidification tank 3, utilizing the abundant biodegradable organic matter in the filtrate as a carbon source for denitrification. This not only enhances the denitrification process and improves the removal rates of nitrates and total nitrogen, but also effectively compensates for the alkalinity consumed during nitrification by generating alkalinity during denitrification, thereby maintaining the system pH stable above 7.0. Compared to existing methods that rely on external carbon sources or alkaline agents, this method reduces operating costs and avoids secondary salt pollution.

[0060] The purpose of micro-aeration is twofold: firstly, to improve the mixing effect of hydrolysis acidification tank 3, prevent bottom sedimentation and local dead zones, and maintain the balance of the microbial community; secondly, to create a micro-aerobic environment to promote the hydrolysis of macromolecular organic matter while avoiding excessive consumption of small molecule organic matter, so as to maximize the accumulation of small molecule degradable carbon sources in the tank; and thirdly, to further inhibit methanogenesis, which is conducive to the accumulation of small molecule degradable organic matter, so that more organic carbon sources can be used for the subsequent denitrification process, thereby improving the overall nitrogen removal efficiency of the system.

[0061] Unlike traditional anaerobic processes, this invention achieves an improved hydrolysis acidification mode that balances optimized mixing, maintenance of microbial activity, and retention of carbon sources. Through this method, the hydrolysis acidification tank 3 can efficiently and stably hydrolyze organic matter, providing suitable water quality for subsequent aerobic reactions, while simultaneously enhancing the available carbon source required for denitrification and improving the overall system's treatment efficiency.

[0062] In this embodiment, the mixture is hydrolyzed and acidified in the hydrolysis acidification tank 3 and then fed into the SBR reaction tank 5. The second aeration component 6 supplies oxygen to the mixture in the SBR reaction tank 5.

[0063] In this embodiment, the SBR reactor 5 adopts a Sequencing Batch Reactor (SBR) operation mode, including stages such as water filling, aeration reaction, sedimentation, and drainage. During the water filling stage, the water is uniformly mixed, providing a suitable reaction environment for microorganisms. During the aeration reaction stage, the second aeration component 6 provides sufficient dissolved oxygen to promote organic matter degradation and ammonia nitrification, ensuring the full degradation of organic matter and nitrogen in the water, while simultaneously forming granular sludge. During the sedimentation stage, due to the cessation of aeration, an anoxic / anaerobic microenvironment is formed within the SBR reactor 5, providing conditions for denitrification. Combined with the carbon source provided by the filtrate, efficient denitrification and alkalinity replenishment are achieved, realizing coupled operation of nitrification and denitrification within the same reactor. This eliminates the need for a separate anoxic tank, simplifying the process and reducing investment and operating costs. This process reduces nitrates to nitrogen, compensating for the alkalinity consumed during the nitrification stage and maintaining system pH stability. During the drainage stage, the supernatant is discharged through a drain pipe, and some of the settled sludge can be recycled to maintain the activated sludge concentration.

[0064] Meanwhile, the periodic hydraulic conditions of the SBR are conducive to the formation and stabilization of granular sludge. The organic carbon source provided by the mixture of filtrate and biogas slurry enables the granular sludge to grow rapidly during the aeration stage, while the granular sludge is enriched during the sedimentation stage due to its good settling performance. Ultimately, stable aerobic granular sludge is formed, which increases the system's biomass and reaction rate, while also improving sedimentation performance, shortening sedimentation time, and enhancing the SBR's operating efficiency and treatment capacity.

[0065] In this invention, the flow rates of the biogas slurry inlet pump 11 and the filtrate inlet pump 21 are controlled by the regulating component 8 to ensure a good carbon-nitrogen ratio in the system. Through combined treatment, the carbon-nitrogen balance required for denitrification can be achieved, thereby stabilizing the pH of the biological reaction system, improving nitrogen removal efficiency, and reducing dependence on external carbon sources and alkali agents.

[0066] In one embodiment, such as Figure 1 As shown, the wastewater treatment system also includes an intermediate water tank 7, which is located between the hydrolysis acidification tank 3 and the SBR reaction tank 5, and the control component 8 is located in the intermediate water tank 7.

[0067] Specifically, in this embodiment, the effluent from the hydrolysis acidification tank 3 flows into the intermediate water tank 7 through a pipeline. After the carbon-nitrogen ratio is adjusted in the intermediate water tank 7, the water flows into the SBR reaction tank 5. The control component 8 can monitor the concentration of degradable organic matter and total nitrogen in the mixed liquid in the intermediate water tank 7 online, assess the nitrogen load, and supplement the external carbon source as needed based on the calculation results.

[0068] In this embodiment, the first inlet of the hydrolysis acidification tank 3 is located in the middle of the first tank body 31, and the first outlet is located in the upper part of the first tank body 31. The second inlet and the second outlet of the SBR reaction tank 5 are located in the middle of the second tank body 51, and the second outlet is lower than the second inlet. The third inlet and the fourth outlet of the intermediate water tank 7 are located in the middle of the intermediate water tank 7 and are lower than the first outlet and the second inlet.

[0069] The present invention includes an intermediate water tank 7 to regulate water flow, buffer water quality fluctuations, and serve as an interface for water quality monitoring and control. A regulating component 8 is provided to supplement the mixed liquor in the intermediate water tank 7 with an external carbon source, ensuring sufficient denitrification conditions.

[0070] In one embodiment, such as Figure 1 As shown, the control component 8 includes a carbon replenishment device 81, a first detector 82, a second detector 83, and a first controller 84. The first detector 82 is installed in the intermediate water tank 7 and is suitable for detecting the concentration of degradable organic matter. The second detector 83 is installed in the intermediate water tank 7 and is suitable for detecting the total nitrogen concentration. The first controller 84 is signal-connected to the first detector 82, the second detector 83, and the carbon replenishment device 81.

[0071] Specifically, this embodiment does not impose specific limitations on the first detector 82 and the second detector 83. For example, in this embodiment, the first detector 82 adopts a Chemical Oxygen Demand (COD) monitoring module for online monitoring of the concentration of degradable organic matter in the mixed liquor, and the second detector 83 adopts a total nitrogen monitoring module for online determination of the total nitrogen concentration. The first controller 84 adopts an intelligent control module. The first detector 82 and the second detector 83 transmit the acquired detection signals to the first controller 84 to evaluate the nitrogen load. The carbon supplementation device 81 can supplement the external carbon source as needed according to the calculation results of the first controller 84.

[0072] In this embodiment, the first controller 84 receives data from the first detector 82 and the second detector 83, calculates the carbon-nitrogen ratio (degradable COD / total nitrogen) of the mixed liquor in real time, and compares it with a preset target ratio. When the carbon-nitrogen ratio meets or exceeds the target value, the system maintains the current mixing ratio of biogas slurry and filtrate; when the carbon-nitrogen ratio is lower than the target value, the first controller 84 can first adjust the flow rates of the biogas slurry inlet pump 11 and the filtrate inlet pump 21 to optimize the mixing ratio; when the preset target ratio still cannot be met after adjusting the ratio, the carbon supplementation device 81 is triggered to supplement carbon, ensuring that the carbon source in the water entering the SBR reactor 5 is sufficient to meet the denitrification requirements.

[0073] In this embodiment, a reactor inlet pump 54 is installed between the intermediate water tank 7 and the SBR reactor 5 to lift and transport the mixed water, which has been adjusted by the regulating component 8, to the SBR reactor 5. Preferably, the reactor inlet pump 54 adopts a variable frequency control method, which can automatically adjust its start / stop and flow rate according to the SBR operating cycle of the SBR reactor 5. For example, it automatically starts during the filling stage and supplies water at a set flow rate, and automatically stops during the aeration, sedimentation, or drainage stages, thereby ensuring the stable and reliable periodic operation of the SBR reactor 5 and achieving precise matching between the filling volume and the SBR cycle, avoiding the impact of water level fluctuations on the aeration and sedimentation stages.

[0074] In this invention, the control component 8 automatically adjusts the mixing ratio of biogas slurry and filtrate by real-time monitoring of the biogas content and total nitrogen content in the mixed liquor, and initiates carbon source addition when necessary. This intelligent control ensures that the carbon-to-nitrogen ratio of the mixed liquor entering the aerobic tank meets the denitrification requirements, achieves dynamic optimization and self-sufficiency balance of denitrification carbon source, improves the denitrification efficiency and stability of the system, and reduces human intervention.

[0075] The present invention uses the concentration of degradable organic matter obtained by the first detector 82 and the total nitrogen concentration obtained by the second detector 83 to achieve dynamic optimization of the mixing ratio of biogas slurry and filtrate and self-sufficiency balance of denitrification carbon source. Without the need for a large amount of external reagents, it can significantly improve nitrogen removal efficiency, reduce operating costs, and adapt to the treatment environment of livestock and poultry wastewater with large fluctuations in water quality.

[0076] In one embodiment, such as Figure 1 As shown, the hydrolysis acidification tank 3 includes a first tank body 31, a first stirrer 32 and a third detector 33. The first stirrer 32 is disposed in the first tank body 31, and the third detector 33 is disposed in the first tank body 31. The third detector 33 is connected to the first aeration component 4 via signal connection.

[0077] Specifically, in this embodiment, the third detector 33 is not specifically limited. For example, in this embodiment, the third detector 33 is a dissolved oxygen meter. The dissolved oxygen meter can monitor the dissolved oxygen concentration in the first tank 31 in real time and transmit the dissolved oxygen concentration data to the first aeration component 4. The first aeration component 4 can adjust the aeration rate in real time according to the dissolved oxygen concentration data.

[0078] In this invention, the first stirrer 32 is used to ensure that the water and microorganisms in the hydrolysis acidification tank 3 are fully mixed, so that the biogas slurry, filtrate and incoming nutrients are evenly distributed, thereby improving the degradation efficiency of the hydrolysis acidification microorganisms and preventing sedimentation or dead zones. The third detector 33 is used to monitor the dissolved oxygen in the hydrolysis acidification tank 3 in real time, providing a control basis for the operation of the first aeration component 4.

[0079] In one embodiment, such as Figure 1 As shown, the first aeration component 4 includes a first air pump 41, a first aeration disc 42, and a second controller 43. The first aeration disc 42 is disposed inside the first tank body 31. The second controller 43 is connected to the first air pump 41 and the first aeration disc 42. The second controller 43 is signal-connected to the third detector 33.

[0080] Specifically, in this embodiment, the first aeration disc 42 is disposed at the bottom of the first tank 31, and a plurality of aeration holes are evenly provided on the first aeration disc 42. The first air pump 41 is an air pump, and the second controller 43 is a gas flow controller. The second controller 43 is connected to the first air pump 41 and the first aeration disc 42, and is also connected to the third detector 33. After the second controller 43 obtains the detection signal from the third detector 33, it can automatically adjust the aeration intensity of the first air pump 41, thereby controlling and regulating the dissolved oxygen concentration in the first tank 31. In this embodiment, the dissolved oxygen in the first tank 31 is preferably controlled between 0.1 mg / L and 0.2 mg / L to avoid inhibiting the activity of absolute anaerobic microorganisms.

[0081] In one embodiment, such as Figure 1 As shown, the SBR reactor 5 includes a second tank body 51, a second stirrer 52 and a fourth detector 53. The second stirrer 52 is located inside the second tank body 51, and the fourth detector 53 is located inside the second tank body 51. The fourth detector 53 is connected to the second aeration assembly 6 via a signal connection.

[0082] Specifically, in this embodiment, the fourth detector 53 is not specifically limited. For example, in this embodiment, the fourth detector 53 is a dissolved oxygen meter. The dissolved oxygen meter can monitor the dissolved oxygen concentration in the second tank 51 in real time and transmit the dissolved oxygen concentration data to the second aeration component 6. The second aeration component 6 can adjust the aeration rate in real time according to the dissolved oxygen concentration data.

[0083] In this embodiment, during the aeration reaction stage, the oxygen supply of the second aeration component 6 and the stirring of the second stirrer 52 work together to fully degrade organic matter and nitrogen in the water, while forming granular sludge.

[0084] In this invention, the second agitator 52 is used to ensure thorough mixing of water and microorganisms during the initial stages of water filling or aeration, so that organic matter and nitrogen in the influent are evenly distributed, preventing sedimentation or dead zones and improving biological reaction efficiency. The fourth detector 53 can monitor the dissolved oxygen concentration in the SBR reactor 5 in real time, providing a control basis for the operation of the second aeration component 6.

[0085] In one embodiment, such as Figure 1 As shown, the second aeration component 6 includes a second air pump 61, a second aeration disc 62, and a third controller 63. The second aeration disc 62 is disposed inside the second pool body 51. The third controller 63 is connected to the second air pump 61 and the second aeration disc 62. The third controller 63 is signal-connected to the fourth detector 53.

[0086] Specifically, in this embodiment, the second aeration disc 62 is located at the bottom of the second tank 51, and a plurality of aeration holes are evenly distributed on the second aeration disc 62. The second air pump 61 is an air pump, and the third controller 63 is a gas flow controller. The third controller 63 is connected to the second air pump 61 and the second aeration disc 62, and is also connected to the fourth detector 53. After the third controller 63 receives the detection signal from the fourth detector 53, it can automatically adjust the aeration intensity of the second air pump 61, thereby regulating the dissolved oxygen concentration in the second tank 51. In this embodiment, the dissolved oxygen in the second tank 51 is preferably controlled between 2 mg / L and 4 mg / L to ensure the activity of nitrifying bacteria and aerobic microorganisms, and to promote the degradation of organic matter and the ammonia nitrogen nitrification process.

[0087] The third controller 63 of the present invention can automatically adjust the aeration intensity of the air pump according to the dissolved oxygen concentration obtained by the fourth detector 53, so as to maintain the dissolved oxygen in the water within a suitable range, ensure the activity of nitrifying bacteria and aerobic microorganisms, and promote the degradation of organic matter and the ammonia nitrogen nitrification process.

[0088] In one embodiment, such as Figure 1 As shown, the wastewater treatment system also includes a first separator 9 and a second separator 10. The first separator 9 is connected to the biogas slurry storage tank 1 and the filtrate storage tank 2, and the second separator 10 is connected to the first separator 9 and the hydrolysis acidification tank 3.

[0089] Specifically, this embodiment does not specifically limit the first separator 9 and the second separator 10. For example, in this embodiment, the first separator 9 adopts a fine screen and the second separator 10 adopts an air flotation device.

[0090] Fine screens are used for preliminary solid-liquid separation of the biogas slurry and filtrate entering the hydrolysis acidification tank 3, removing larger suspended solids, coarse fibers, feed residues, and other impurities from the water, thereby preventing clogging and wear of the subsequent air flotation unit, hydrolysis acidification tank 3, and SBR reactor 5. The spacing between the bars in the fine screen ranges from several millimeters to tens of millimeters, which can be selected according to the characteristics of suspended solids in the water. After the biogas slurry and filtrate are treated by the fine screen, larger particles in the water are intercepted and discharged, significantly reducing the suspended solids content in the water flowing into the air flotation unit. This is beneficial to the air flotation effect and the operational stability of the subsequent bioreactor, while also improving the overall treatment efficiency and reliability of the system.

[0091] Located after the fine screen, the dissolved air flotation (DAF) unit is primarily used to remove fine suspended solids, colloidal substances, grease, and some floatable impurities from the water, thereby reducing turbidity and COD load. The DAF unit introduces microbubbles into the water, causing suspended particles or grease to adhere to the bubble surface, forming scum. This scum accumulates on the surface and is then removed by a scraper. After treatment by the DAF unit, the content of suspended solids and colloidal substances in the water is significantly reduced, effectively alleviating the load on the subsequent hydrolysis acidification tank 3 and SBR reactor 5, improving biological treatment efficiency, and reducing the risk of pipe and reactor blockage.

[0092] In this embodiment, the biogas slurry in the biogas slurry storage tank 1 is transported to the fine screen via a pipeline by the biogas slurry inlet pump 11, and the filtrate in the filtrate storage tank 2 is transported to the same fine screen via a separate pipeline by the filtrate inlet pump 21. The fine screen and the flotation device are shared equipment, but the biogas slurry and filtrate pipelines are independent, and their respective flow rates can be adjusted by valves to achieve flexible control of the ratio of the two water sources. The biogas slurry and filtrate, after pretreatment by the fine screen and flotation device, flow into a combined mixing pipeline section and then into the hydrolysis acidification tank 3 for subsequent biological treatment.

[0093] In this embodiment, both the biogas slurry and the filtrate undergo pretreatment with a fine screen and an air flotation device to remove large suspended solids, grease, and colloids, ensuring the stable operation of subsequent biological treatment units. Although the fine screen and air flotation device are shared equipment, the inlet pipes for the two water bodies are independent and equipped with valves for regulation, allowing for flexible control of the mixing ratio based on inlet water quality and load. This avoids pretreatment instability caused by significant differences in water quality and provides a controllable C / N ratio adjustment method for subsequent processes. Combined with the control component 8, dynamic optimization of the mixed liquor's carbon-nitrogen ratio can be achieved, providing a controllable, stable, and efficient treatment strategy for system operation under different water quality conditions.

[0094] In this invention, both the biogas slurry and the filtrate are pretreated by the first separator 9 and the second separator 10, which can remove large particulate suspended solids, oils and colloids, and protect the stable operation of the subsequent biological treatment unit.

[0095] This invention offers high operational flexibility, allowing for dynamic optimization of operating parameters based on varying water quality and treatment objectives. First, the biogas slurry and filtrate enter the fine screen and flotation device separately via independent inlet pipes. At the mixing section, the flow rate ratio of the two water bodies can be flexibly adjusted using an inlet pump to control the carbon-to-nitrogen ratio entering the subsequent biological reaction system, meeting denitrification requirements under different load conditions. Second, the SBR reactor 5 operates in SBR mode, with the duration of each stage—filling, aeration, sedimentation, and drainage—dynamically adjustable based on water quality characteristics and treatment objectives, thereby balancing organic matter removal and nitrogen conversion efficiency. Third, the micro-aeration rate in the hydrolysis acidification tank 3 is automatically adjusted according to the biogas slurry load. It is appropriately increased under high loads to enhance mixing and maintain microbial activity, and reduced under low loads to save energy and avoid inhibiting anaerobic microorganisms. Through these flexible and adjustable operating methods, this invention can adapt to water quality fluctuations and different operating conditions, ensuring stable effluent compliance while improving the system's economic efficiency and reliability.

[0096] According to an embodiment of the present invention, on the other hand, such as Figure 2 As shown, a wastewater treatment method is also provided, which uses the wastewater treatment system of the above embodiment. The treatment method includes the following steps:

[0097] The biogas slurry in biogas slurry storage tank 1 and the filtrate in filtrate storage tank 2 are mixed in proportion and then fed into hydrolysis acidification tank 3.

[0098] Specifically, the biogas slurry in biogas slurry storage tank 1 is transported to the fine screen via a pipeline by biogas slurry inlet pump 11, and the filtrate in filtrate storage tank 2 is transported to the fine screen via a separate pipeline by filtrate inlet pump 21. After pretreatment by the air flotation device, the filtrate flows into the combined mixing section and then into the hydrolysis acidification tank 3 for subsequent biological treatment. When biogas slurry and filtrate are fed into the fine screen, the flow rates of biogas slurry and filtrate can be adjusted by valves to ensure that the mixture meets the required ratio.

[0099] Start the first stirrer 32 and start the first aeration component 4 to input a small amount of aeration into the hydrolysis acidification tank 3.

[0100] Specifically, the first air pump 41 is started to input a small amount of air into the first aeration disc 42, generating a small amount of aeration in the hydrolysis acidification tank 3, and the first agitator 32 is started at the same time.

[0101] Obtain the dissolved oxygen concentration in the water of hydrolysis acidification tank 3.

[0102] Specifically, the third detector 33 acquires the dissolved oxygen concentration in the hydrolysis acidification tank 3 in real time and transmits the acquired data to the second controller 43.

[0103] Adjust the aeration rate of the first aeration component 4 according to the dissolved oxygen concentration in the water of the hydrolysis acidification tank 3.

[0104] Specifically, the second controller 43 adjusts the first air pump 41 according to the dissolved oxygen concentration obtained by the third detector 33, so that the dissolved oxygen in the hydrolysis acidification tank 3 is controlled between 0.1 mg / L and 0.2 mg / L.

[0105] The water in the hydrolysis acidification tank 3 is transferred into the intermediate water tank 7.

[0106] Specifically, the effluent from the hydrolysis acidification tank 3 flows into the intermediate water tank 7 through a pipeline.

[0107] The concentrations of degradable organic matter and total nitrogen in the water of intermediate pool 7 were obtained.

[0108] Specifically, the first detector 82 monitors the concentration of degradable organic matter in the mixture in real time, the second detector 83 measures the total nitrogen concentration in the mixture in real time, and transmits the acquired data to the first controller 84.

[0109] Adjust the carbon-nitrogen ratio of the water in intermediate pool 7.

[0110] Specifically, the first controller 84 receives data from the first detector 82 and the second detector 83, calculates the carbon-nitrogen ratio of the mixed liquor in real time, and compares it with a preset target ratio. Based on the comparison result, the first controller 84 adjusts the carbon-nitrogen ratio of the water in the pool accordingly to ensure that the water entering the SBR reactor 5 has sufficient carbon source to meet the denitrification requirements.

[0111] The water in the intermediate water tank 7 is fed into the SBR reactor 5.

[0112] Specifically, the reactor inlet pump 54 lifts and delivers the mixed liquid, which has been adjusted by the control component 8, to the SBR reactor 5.

[0113] Obtain the dissolved oxygen concentration in the water of SBR reactor 5.

[0114] Specifically, the fourth detector 53 monitors the dissolved oxygen concentration in the second pool 51 in real time and transmits the acquired data to the third controller 63.

[0115] Adjust the aeration rate of the second aeration component 6 according to the dissolved oxygen concentration in the water of the SBR reactor 5.

[0116] Specifically, the third controller 63 adjusts the second air pump 61 based on the dissolved oxygen concentration obtained by the fourth detector 53, so that the dissolved oxygen in the hydrolysis acidification tank 3 is controlled between 2 mg / L and 4 mg / L.

[0117] Compared to traditional anaerobic processes, this invention achieves an improved hydrolysis acidification mode that balances mixture optimization, maintenance of microbial activity, and carbon source retention. Through this method, the hydrolysis acidification tank 3 can efficiently and stably hydrolyze organic matter, providing suitable water quality for subsequent aerobic reactions, while simultaneously enhancing the available carbon source required for denitrification and improving the overall system's treatment efficiency.

[0118] In one embodiment, the step of adjusting the carbon-to-nitrogen ratio of the water in the intermediate pool 7 includes:

[0119] Based on the concentration of degradable organic matter and total nitrogen in the water of intermediate pool 7, the carbon-nitrogen ratio of the water is calculated in real time and compared with the preset target ratio.

[0120] If the carbon-to-nitrogen ratio meets or exceeds the target value, the system maintains the current mixing ratio of biogas slurry and filtrate;

[0121] If the carbon-nitrogen ratio is lower than the target value, adjust the flow rate of biogas slurry and filtrate into hydrolysis acidification tank 3;

[0122] If the preset target ratio cannot be met after adjusting the ratio, the carbon replenishment device 81 is activated to replenish carbon to the intermediate water tank 7.

[0123] Specifically, when the carbon-nitrogen ratio meets or exceeds the target value, the system maintains the current mixing ratio of biogas slurry and filtrate; when the carbon-nitrogen ratio is lower than the target value, the first controller 84 sends a signal to the biogas slurry inlet pump 11 and the filtrate inlet pump 21 to adjust the flow rates of the biogas slurry inlet pump 11 and the filtrate inlet pump 21 to optimize the mixing ratio until the carbon-nitrogen ratio meets the target value; when the preset target ratio still cannot be met after adjusting the ratio, the first controller 84 sends a signal to the carbon supplementation device 81 to supplement carbon into the intermediate water tank 7 until the carbon-nitrogen ratio meets the target value.

[0124] This invention, through the adjustment of the carbon supplementation device 81, can achieve dynamic optimization of the mixing ratio of biogas slurry and filtrate, and self-sufficiency balance of denitrification carbon source. Without the need for a large amount of external reagents, it can significantly improve nitrogen removal efficiency, reduce operating costs, and adapt to the treatment environment of livestock and poultry wastewater with large fluctuations in water quality.

[0125] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method of treating wastewater, characterized by, The wastewater treatment system employs the following steps: The biogas slurry in the biogas slurry storage tank (1) and the filtrate in the filtrate storage tank (2) are mixed in proportion and then fed into the hydrolysis acidification tank (3). Start the first agitator (32) and start the first aeration component (4) to input a small amount of aeration into the hydrolysis acidification tank (3); Obtain the dissolved oxygen concentration in the water of the hydrolysis acidification tank (3); Adjust the aeration rate of the first aeration component (4) according to the dissolved oxygen concentration in the water in the hydrolysis acidification tank (3); The water in the hydrolysis acidification tank (3) is fed into the intermediate water tank (7); Obtain the concentration of degradable organic matter and total nitrogen in the water of the intermediate pool (7); Adjust the carbon-nitrogen ratio of the water in the intermediate pool (7); The water in the intermediate water tank (7) is fed into the SBR reactor (5); Obtain the dissolved oxygen concentration in the water of the SBR reactor (5); Adjust the aeration rate of the second aeration component (6) according to the dissolved oxygen concentration in the water in the SBR reactor (5); The step of adjusting the carbon-nitrogen ratio of the water in the intermediate water tank (7) includes: Based on the concentration of degradable organic matter and total nitrogen in the water in the intermediate pool (7), the carbon-nitrogen ratio of the water is calculated in real time and compared with the preset target ratio. If the carbon-to-nitrogen ratio meets or exceeds the target value, the system maintains the current mixing ratio of biogas slurry and filtrate; If the carbon-nitrogen ratio is lower than the target value, adjust the flow rate of biogas slurry and filtrate into the hydrolysis acidification tank (3); If the preset target ratio cannot be met after adjusting the ratio, start the carbon replenishment device (81) to replenish carbon to the intermediate water tank (7); The wastewater treatment system includes: A biogas slurry storage tank (1), wherein the biogas slurry storage tank (1) is suitable for holding biogas slurry; Filtrate storage tank (2), wherein the filtrate storage tank (2) is suitable for holding filtrate; The hydrolysis acidification tank (3) is connected to the biogas slurry storage tank (1) and the filtrate storage tank (2). A biogas slurry inlet pump (11) is provided between the biogas slurry storage tank (1) and the hydrolysis acidification tank (3), and a filtrate inlet pump (21) is provided between the filtrate storage tank (2) and the hydrolysis acidification tank (3). The first aeration component (4) is connected to the hydrolysis acidification tank (3) and is adapted to input a small amount of aeration into the hydrolysis acidification tank (3). SBR reactor (5), which is connected to the hydrolysis acidification tank (3), and the SBR reactor (5) is suitable for cultivating aerobic granular sludge; The second aeration component (6) is connected to the SBR reactor (5); Control component (8), which is signal connected to the biogas slurry inlet pump (11) and the filtrate inlet pump (21); An intermediate water tank (7) is located between the hydrolysis acidification tank (3) and the SBR reaction tank (5), and the control component (8) is located in the intermediate water tank (7). The control component (8) includes: Carbon replenishment device (81); A first detector (82) is disposed in the intermediate water tank (7) and is adapted to detect the concentration of degradable organic matter. A second detector (83) is disposed in the intermediate water tank (7) and is adapted to detect the total nitrogen concentration; The first controller (84) is signal-connected to the first detector (82), the second detector (83) and the carbon replenishment device (81).

2. The wastewater treatment method according to claim 1, characterized by, The hydrolysis acidification tank (3) includes: First pool (31); The first agitator (32) is disposed inside the first tank body (31); The third detector (33) is installed inside the first pool body (31) and is signal-connected to the first aeration component (4).

3. The wastewater treatment method according to claim 2, characterized by, The first aeration component (4) includes: First air pump (41); The first aeration disc (42) is disposed inside the first pool body (31); The second controller (43) is connected to the first air pump (41) and the first aeration disc (42), and the second controller (43) is signal-connected to the third detector (33).

4. The wastewater treatment method according to claim 1, characterized by, The SBR reactor (5) includes: Second pool (51); The second agitator (52) is disposed inside the second tank body (51); The fourth detector (53) is located inside the second pool body (51) and is signal-connected to the second aeration component (6).

5. The wastewater treatment method according to claim 4, characterized by, The second aeration component (6) includes: Second air pump (61); The second aeration disc (62) is disposed inside the second pool body (51); The third controller (63) is connected to the second air pump (61) and the second aeration disc (62), and the third controller (63) is signal-connected to the fourth detector (53).

6. The wastewater treatment method according to claim 1, characterized by, The wastewater treatment system also includes: The first separator (9) is connected to the biogas slurry storage tank (1) and the filtrate storage tank (2); The second separator (10) is connected to the first separator (9) and the hydrolysis acidification tank (3).

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