Advanced denitrification treatment system for kitchen waste fermentation wastewater

Abstract

The utility model discloses a deep denitrification treatment system for kitchen waste fermentation wastewater, which belongs to the technical field of sewage treatment and comprises an adjusting tank, an anaerobic bioreactor, a completely mixed aeration tank, a sulfur-iron synergistic denitrification reactor and a clean water tank, the adjusting tank, the anaerobic bioreactor, the complete mixing type aeration tank, the sulfur-iron synergistic denitrification reactor and the clean water tank are connected through pipelines; a water collecting well is arranged at the front end of the anaerobic bioreactor, and a clean water tank is arranged at one end of the sulfur-iron synergistic denitrification reactor. According to the present invention, the sulfur-iron synergistic autotrophic denitrification deep nitrogen removal reaction can be performed on the low C / N ratio and high nitrogen load effluent by using the front end coagulation precipitation, the anaerobic biological treatment, the aerobic biological treatment and other process units so as to improve the nitrogen removal efficiency, reduce the operation cost and ensure the up-to-standard discharge of the effluent.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, specifically relating to a deep denitrification treatment system for kitchen waste fermentation wastewater. Background Technology

[0002] The statements in this section are merely background information related to this utility model and do not necessarily constitute prior art.

[0003] Food waste fermentation wastewater is characterized by high COD and ammonia nitrogen content, rich in animal and vegetable oils and crude fiber, and a low C / N ratio. Currently, its wastewater treatment mainly employs a combination of multiple process units, including coagulation sedimentation, anaerobic biological treatment, aerobic biological treatment, and advanced oxidation. However, traditional denitrification technologies for food waste fermentation wastewater suffer from increasingly prominent problems such as low nitrate removal efficiency leading to substandard total nitrogen emissions, high costs for carbon sources and reagents, and complex operation and management. Therefore, a highly efficient and low-cost biological denitrification technology is urgently needed. In the process of sulfur autotrophic denitrification, microorganisms utilize inorganic carbon sources such as CO2 for growth and sulfur as an electron donor, while NO3... - Acting as an electron acceptor, it converts nitrate nitrogen into nitrogen gas, thus completing nitrogen removal. It is well-known for its good nitrogen removal performance even under low COD and low C / N ratio conditions, and sulfur autotrophic denitrification technology has begun to be applied in engineering projects.

[0004] However, current sulfur autotrophic denitrification technology is mainly concentrated in wastewater with low nitrogen concentration and low C / N ratio, and its application in wastewater with high nitrogen concentration and low C / N ratio is less common. The sulfur autotrophic denitrification process favors alkalinity and produces acid, requiring timely replenishment of alkalinity to prevent pH drop and subsequent sulfur disproportionation. Under high nitrogen loads, the reaction easily produces large amounts of SO4. 2- To produce SO4 in the water 2- The emission standards are too high, making it impossible to meet the emission standards. Utility Model Content

[0005] To address the aforementioned issues, this invention provides a deep denitrification treatment system for kitchen waste fermentation wastewater. This system utilizes upstream coagulation and sedimentation, anaerobic biological treatment, and aerobic biological treatment processes to perform a sulfur-iron synergistic autotrophic denitrification reaction on effluent with low C / N ratios and high nitrogen loads. This improves denitrification efficiency, reduces operating costs, and ensures that the effluent meets discharge standards.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A deep denitrification treatment system for kitchen waste fermentation wastewater includes an equalization tank, an anaerobic bioreactor, a completely mixed aeration tank, a sulfur-iron synergistic denitrification reactor, and a clear water tank; the equalization tank, anaerobic bioreactor, completely mixed aeration tank, sulfur-iron synergistic denitrification reactor, and clear water tank are connected by pipelines; a water collection well is set at the front end of the anaerobic bioreactor, and a clear water tank is set at one end of the sulfur-iron synergistic denitrification reactor.

[0008] Furthermore, one end of the equalization tank is connected to the anaerobic bioreactor, and the other end of the equalization tank is the inlet end; wastewater is introduced into the equalization tank, and the equalization tank is connected to the acid-base dosing system.

[0009] Furthermore, the acid-base dosing system is electrically connected to the PLC automatic control system, which is used to calculate the acid-base dosing amount.

[0010] Furthermore, the anaerobic bioreactor is electrically connected to the PLC automatic control system, and the water collection well is connected to the anaerobic bioreactor via a pipeline, and the water collection well is also electrically connected to the PLC automatic control system.

[0011] Furthermore, one end of the anaerobic bioreactor is connected to a completely mixed aeration tank, and one end of the completely mixed aeration tank is connected to a sulfur-iron co-denitrification reactor.

[0012] Furthermore, a branch is provided on the pipeline connecting the fully mixed aeration tank and the sulfur-iron synergistic denitrification reactor, and the branch contains sludge, which is returned to the fully mixed aeration tank.

[0013] Furthermore, the sulfur-iron synergistic denitrification reactor is filled with a specially made functional composite packing material, which is composed of sulfur, siderite, and bluestone powder.

[0014] Furthermore, the sulfur-iron synergistic denitrification reactor is electrically connected to the PLC automatic control system.

[0015] Furthermore, one end of the sulfur-iron synergistic denitrification reactor is connected to a clear water tank, which is used for temporary storage of backwash water.

[0016] Furthermore, one end of the clear water tank is provided with a branch line, which is connected to the sulfur-iron synergistic denitrification reactor; the other end of the clear water tank is the outlet.

[0017] Compared with the prior art, the advantages and positive effects of this utility model are:

[0018] 1. This utility model relies on front-end anaerobic biological treatment and aerobic biological treatment to remove most of the COD in the water. Under high-intensity aeration, the total nitrogen is mostly in the form of nitrate nitrogen, providing a reaction basis for sulfur-iron synergistic denitrification.

[0019] 2. The sulfur-iron synergistic denitrification process of this invention has a good denitrification effect on wastewater with low C / N ratio and high nitrogen load, without the need for external organic carbon sources, thus saving operating costs. Compared with denitrification processes such as short-cut nitrification-denitrification and anaerobic ammonium oxidation, it has simpler operating conditions, stronger resistance to load shocks, and is easier to implement in engineering projects.

[0020] 3. This invention unifies sulfur autotrophic denitrification and iron autotrophic denitrification into the same system, combining the characteristics of both and avoiding the shortcomings of using them separately. The iron autotrophic process can consume the H2 produced by the sulfur autotrophic process. + It replenishes alkalinity and can also share the denitrification load, improving denitrification efficiency and reducing SO4. 2- produce.

[0021] 4. This utility model's sulfur-iron synergistic denitrification reactor is in tank form, requiring a small footprint and low investment cost. The composite packing integrates sulfur, siderite, and bluestone, providing ample S and Fe for the autotrophic denitrification reaction. 2+ The isoelectric donor, alkalinity, and inorganic carbon source are added once and require no additional replenishment during operation, simplifying management. Simultaneously, the composite packing provides attachment points for microorganisms, promoting the accumulation of autotrophic denitrifying bacteria.

[0022] 5. The PLC automatic control system of this utility model can adjust the sewage treatment operation parameters online, realize remote and precise dosing, save manpower, reduce operating costs, and has a high degree of automation and intelligence. Attached Figure Description

[0023] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0024] Figure 1 This is a diagram of a deep denitrification treatment system for kitchen waste fermentation wastewater according to this utility model;

[0025] In the diagram: 1. Equalization tank; 2. Anaerobic bioreactor; 3. Completely mixed aeration tank; 4. Sulfur-iron synergistic denitrification reactor; 5. Clear water tank. Detailed Implementation

[0026] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0027] Currently, sulfur autotrophic denitrification technology is mainly concentrated in wastewater with low nitrogen concentration and low C / N ratio, and its application in wastewater with high nitrogen concentration and low C / N ratio is less common. The sulfur autotrophic denitrification process favors alkalinity and produces acid, requiring timely replenishment of alkalinity to prevent pH drop and subsequent sulfur disproportionation. Under high nitrogen loads, the reaction easily produces large amounts of SO4. 2- To produce SO4 in the water 2- The emission standards are too high, making it impossible to meet the emission standards.

[0028] The present invention will now be described in detail with reference to the accompanying drawings. This embodiment discloses a deep denitrification treatment system for kitchen waste fermentation wastewater, such as... Figure 1 As shown, it includes an equalization tank 1, an anaerobic bioreactor 2, a completely mixed aeration tank 3, a sulfur-iron synergistic denitrification reactor 4, and a clear water tank 5; the equalization tank 1, the anaerobic bioreactor 2, the completely mixed aeration tank 3, the sulfur-iron synergistic denitrification reactor 4, and the clear water tank 5 are connected by pipes; a water collection well is set at the front end of the anaerobic bioreactor 2, and a clear water tank 5 is set at one end of the sulfur-iron synergistic denitrification reactor 4.

[0029] One end of the equalization tank 1 is connected to the anaerobic bioreactor 2, and the other end is the inlet. Wastewater is introduced into the equalization tank 1, which is also connected to the acid-base dosing system. The acid-base dosing system is electrically connected to a PLC automatic control system, which calculates the acid-base dosage. A Siemens S7-1200 PLC can be used. The monitoring and calculation functions of the PLC automatic control system are easily implemented using existing technology and do not involve improvements to the software algorithm.

[0030] Incoming water first enters equalization tank 1 to regulate water quality and quantity, preventing excessive fluctuations that could affect system stability when wastewater enters the biological treatment system. Simultaneously, the pH of the wastewater is adjusted to suit the acidity and alkalinity of the biological treatment system. The pH meter is linked to the acid-base dosing system, with a pH range of 6-7.5. The PLC automatic control system simulates and calculates the acid-base dosing dosage online for precise dosing.

[0031] The pH meter monitors the pH value of the incoming water. When the pH of the incoming water is less than 6, the PLC automatic control system simulates and calculates the amount of alkali to be added online and controls the acid-base dosing system to add alkali solution to adjust the pH of the incoming water to 6-7.5. Similarly, when the pH of the incoming water is greater than 7.5, the PLC automatic control system simulates and calculates the amount of acid to be added online and controls the acid-base dosing system to add sulfuric acid.

[0032] The fermentation wastewater from food waste has a high COD concentration and fluctuates greatly. The wastewater enters anaerobic bioreactor 2, where microorganisms anaerobicly degrade organic matter. This bioreactor can adapt to high COD loads and has strong shock resistance, requiring no aeration and significantly saving energy. Anaerobic bioreactor 2 removes most of the COD from the wastewater and converts organic nitrogen into ammonia nitrogen. The PLC automatic control system displays the influent and effluent COD, ammonia nitrogen, and total nitrogen concentrations, influent flow rate, and volumetric load in real time. Simultaneously, a fault warning system monitors fluctuations in effluent indicators and is set to alarm when the fluctuation rate exceeds 20%, alerting technicians to investigate the problem.

[0033] Anaerobic bioreactor 2 is electrically connected to the PLC automatic control system. The water collection well is connected to anaerobic bioreactor 2 via a pipeline and is also electrically connected to the PLC automatic control system. One end of anaerobic bioreactor 2 is connected to completely mixed aeration tank 3, and one end of completely mixed aeration tank 3 is connected to sulfur-iron co-denitrification reactor 4.

[0034] A branch line is set on the pipeline connecting the fully mixed aeration tank 3 and the sulfur-iron co-denitrification reactor 4. The branch line contains sludge, which is returned to the fully mixed aeration tank 3.

[0035] The anaerobic bioreactor 2 has a water collection well at the front end to raise the water temperature. The designed inlet water temperature is 35±2℃, and the PLC automatic control system can monitor the inlet water temperature online.

[0036] The fully mixed aeration tank 3 serves as a pre-treatment unit for autotrophic denitrification. Through high-intensity aeration, nitrifying bacteria convert ammonia nitrogen into nitrate nitrogen, while also consuming some COD. When wastewater and returned sludge enter the aeration tank, they are rapidly and thoroughly mixed and homogenized with the existing mixed liquor, maintaining a balanced concentration of pollutants within the tank and exhibiting high resistance to shock loads.

[0037] Under the high-intensity aeration, almost all the nitrogen entering the sulfur-iron co-denitrification reactor 4 is nitrate nitrogen. Under the action of autotrophic denitrifying bacteria, deep denitrification is completed, ensuring that the effluent meets the discharge standards.

[0038] The sulfur-iron co-denitrification reactor 4 is filled with a specially designed functional composite packing material composed of sulfur, siderite, and bluestone powder. The sulfur-iron co-denitrification reactor 4 is electrically connected to a PLC automatic control system. One end of the sulfur-iron co-denitrification reactor 4 is connected to a clear water tank 5, which is used for temporary storage of backwash water. A branch line is located at one end of the clear water tank 5, connecting to the sulfur-iron co-denitrification reactor 4; the other end of the clear water tank 5 is the outlet.

[0039] The sulfur-iron co-catalytic denitrification reactor 4 is filled with specially designed functional composite packing material, mainly composed of effective components such as sulfur, siderite, and bluestone powder, providing electron donors, inorganic carbon sources, and alkalinity for the autotrophic denitrification reaction. Sulfur provides sulfur for the sulfur autotrophic denitrification reaction.0 As an electron donor, denitrification is completed under the action of denitrifying thiobacilli. Sulfotrophic denitrification is an alkali-consuming and acid-producing process; insufficient buffering agents in the system will cause the pH to drop. Excessively low pH affects microbial growth and metabolism, leading to low denitrification efficiency. The presence of siderite can utilize the H+ produced by sulfur autotrophic denitrification. + To promote the forward hydrolysis of FeCO3, thereby allowing more Fe to be released. 2+ The dissolved iron ore promotes the occurrence of iron autotrophic denitrification, shares the nitrogen removal load of the sulfur autotrophic denitrification process, and replenishes alkalinity to prevent sulfur disproportionation. However, relying solely on siderite to compensate for alkalinity can easily lead to severe accumulation of nitrite in the effluent; therefore, quartz powder is added as an additional alkalinity compensation.

[0040] The PLC automatic control system displays the COD, ammonia nitrogen, nitrate nitrogen, total nitrogen concentration, and pH of the influent and effluent of the sulfur-iron co-denitrification reactor 4 in real time. At the same time, the fault early warning system monitors the fluctuation of the effluent indicators and sets an alarm when the fluctuation rate exceeds 20%, reminding technicians to investigate the problem.

[0041] The sulfur-iron co-denitrification reactor 4 suffers from packing blockage due to excessive biofilm buildup caused by microbial growth. Therefore, periodic combined air-water backwashing is necessary. The PLC control system sets the backwashing program and cycle, automatically controlling the start and stop of the electric valves to complete the backwashing process.

[0042] A deep denitrification treatment system for kitchen waste fermentation wastewater has been put into practical use in a kitchen waste fermentation wastewater treatment system upgrading project in Jiangsu Province, with a raw water volume of 350m³. 3The wastewater had a daily concentration of COD 5500 mg / L, ammonia nitrogen 1500 mg / L, and total nitrogen 2000 mg / L. The original wastewater treatment system consisted of: influent first entering equalization tank 1 to adjust pH and balance water quality and quantity; then, after being heated to 35°C by steam, it entered the anaerobic reactor, followed by a sedimentation tank and then a traditional A / O treatment system for denitrification. The effluent had a COD of 450 mg / L, ammonia nitrogen of 10 mg / L, total nitrogen of 750 mg / L, and a pH of 7.5. The total nitrogen concentration in the effluent did not meet discharge requirements. Because most of the total nitrogen in the effluent was in the form of nitrate nitrogen, the C / N ratio was low, necessitating an upgrade to the wastewater treatment system. Based on the front-end anaerobic biological treatment and A / O treatment of the effluent, a secondary sulfur-iron co-denitrification reactor 4 was added. The reactor was made of corrosion-resistant carbon steel, with a bottom radius of 4m and a height of 12m, and was filled with functional composite packing material to one-third of the total tank volume. The backwashing system is controlled by a PLC automatic control system, with a backwash cycle of 14 days. The backwashing method is air washing + combined air-water backwashing + water washing. The PLC monitors various water quality parameters online, and there is also an automatic alarm system for abnormal data. After the project was commissioned and operated stably, the effluent from the first-stage sulfur-iron co-denitrification reactor 4 had a total nitrogen of 90 mg / L, ammonia nitrogen of 10 mg / L, nitrate nitrogen of 60 mg / L, and pH of 6.6. The effluent from the second-stage sulfur-iron co-denitrification reactor 4 had a total nitrogen of 13 mg / L, ammonia nitrogen of 8 mg / L, nitrate nitrogen of 4 mg / L, and pH of 6.8. No nitrite was detected, ensuring that the effluent meets the discharge standards.

[0043] The sulfur-iron synergistic denitrification reactor 4 maintains high denitrification efficiency even under low C / N ratio and high nitrogen load, ensuring that the system effluent meets discharge standards. The composite packing provides electron donors, inorganic carbon sources, and alkalinity for the reaction, eliminating the need for external carbon sources. Iron autotrophic denitrification consumes the H₂ produced by sulfur autotrophic denitrification. + Alkalinity compensation is performed to maintain system pH stability, while also sharing the nitrogen removal load of sulfur autotrophic denitrification and improving nitrogen removal efficiency.

[0044] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. A deep denitrification treatment system for fermentation wastewater of kitchen waste, characterized in that, It includes an equalization tank, an anaerobic bioreactor, a completely mixed aeration tank, a sulfur-iron synergistic denitrification reactor, and a clear water tank; the equalization tank, the anaerobic bioreactor, the completely mixed aeration tank, the sulfur-iron synergistic denitrification reactor, and the clear water tank are connected by pipelines; a water collection well is set at the front end of the anaerobic bioreactor, and a clear water tank is set at one end of the sulfur-iron synergistic denitrification reactor.

2. The system for deep denitrification treatment of fermentation wastewater of kitchen waste according to claim 1, characterized in that, One end of the equalization tank is connected to the anaerobic bioreactor, and the other end of the equalization tank is the inlet end; wastewater is introduced into the equalization tank, and the equalization tank is connected to the acid-base dosing system.

3. The system for deep denitrification treatment of fermentation wastewater of kitchen waste according to claim 2, characterized in that, The acid-base dosing system is electrically connected to the PLC automatic control system, which is used to calculate the acid-base dosing amount.

4. The system for deep denitrification treatment of fermentation wastewater of kitchen waste according to claim 1, characterized in that, The anaerobic bioreactor is electrically connected to the PLC automatic control system, and the water collection well is connected to the anaerobic bioreactor through a pipeline. The water collection well is also electrically connected to the PLC automatic control system.

5. The system for deep denitrification treatment of fermentation wastewater of kitchen waste according to claim 1, characterized in that, One end of the anaerobic bioreactor is connected to a completely mixed aeration tank, and the other end of the completely mixed aeration tank is connected to a sulfur-iron co-denitrification reactor.

6. The system for advanced denitrification treatment of fermentation wastewater of kitchen waste according to claim 5, characterized in that, A branch line is installed on the pipeline connecting the fully mixed aeration tank and the sulfur-iron synergistic denitrification reactor. The branch line contains sludge, which is then returned to the fully mixed aeration tank.

7. The system for deep denitrification treatment of fermentation wastewater of kitchen waste according to claim 1, characterized in that, The sulfur-iron synergistic denitrification reactor is filled with a specially made functional composite packing material, which is composed of sulfur, siderite, and bluestone powder.

8. The system for deep denitrification treatment of fermentation wastewater of kitchen waste according to claim 1, characterized in that, The sulfur-iron synergistic denitrification reactor is electrically connected to the PLC automatic control system.

9. The system for deep denitrification treatment of fermentation wastewater of kitchen waste according to claim 1, characterized in that, One end of the sulfur-iron synergistic denitrification reactor is connected to a clear water tank, which is used for temporary storage of backwash water.

10. The system for advanced denitrification treatment of fermentation wastewater of kitchen waste according to claim 9, characterized in that, One end of the clear water tank is provided with a branch line, which is connected to the sulfur-iron synergistic denitrification reactor; the other end of the clear water tank is the outlet.

Images