Dual mode coupled pd / a sewage denitrification device

Abstract

This invention discloses a dual-mode coupled PD / A wastewater denitrification device, relating to the field of wastewater treatment technology. It includes a secondary sedimentation tank, a pilot-scale denitrification reactor, and a central control system. The pilot-scale denitrification reactor comprises multiple reaction chambers connected in series. The head reaction chamber has a first inlet, a first outlet, a first sludge return inlet, and a nitrified liquor return outlet. The tail reaction chamber has a second inlet, a second outlet, and a third sludge return inlet. A reaction chamber adjacent to the tail reaction chamber has a nitrified liquor return inlet. A reaction chamber between the head and tail reaction chambers has a second sludge return inlet. The first and second outlets are connected to the inlet of the secondary sedimentation tank. The first, second, and third sludge return inlets are all connected to the sludge outlet of the secondary sedimentation tank. The nitrified liquor return outlet is connected to the nitrified liquor return inlet. This invention features dual-mode switching and has broad applicability.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a dual-mode coupled PD / A wastewater denitrification device. Background Technology

[0002] Currently, eutrophication of water bodies is a prominent problem. Domestic sewage, as the main source of nitrogen and phosphorus pollution, continues to rise in discharge. Traditional AAO processes are unable to meet the demand due to high energy consumption (requiring aeration and external carbon sources), low efficiency (insufficient carbon sources when treating low C / N sewage), and greenhouse gas (such as N2O) emissions.

[0003] Anammox technology directly converts ammonia nitrogen and nitrite nitrogen into nitrogen gas through autotrophic bacteria, saving 60% of aeration energy consumption, 100% of external carbon sources, and reducing sludge production and greenhouse gas emissions. However, its application is mostly concentrated in high ammonia nitrogen wastewater (such as sludge nitrification liquor), and it still faces a bottleneck in large-scale application in mainstream urban wastewater (low ammonia nitrogen, low temperature, and high volatility).

[0004] Short-cut denitrification-anaerobic ammonia oxidation (PD / A) technology offers a new approach to overcoming the current challenges. PD / A reduces nitrate nitrogen to nitrite nitrogen by precisely controlling denitrifying bacteria, providing a stable substrate for Anammox bacteria and achieving efficient nitrogen removal from low C / N wastewater. Studies show that PD / A can improve nitrogen removal efficiency by 16.9%-90% and reduce sludge consumption by 68% and carbon source consumption by 80%. However, most current PD / A processes are similar to AAO treatment processes, but they are difficult to implement for AOA treatment, thus limiting their application. Therefore, a dual-mode coupled PD / A wastewater denitrification device is urgently needed to solve the aforementioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-mode coupled PD / A wastewater denitrification device to solve the problems existing in the prior art, which has a dual-mode switching function and has a wide range of applicability.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides a dual-mode coupled PD / A wastewater denitrification device, comprising a secondary sedimentation tank, a pilot-scale denitrification reactor, and a central control system. The pilot-scale denitrification reactor includes multiple reaction chambers connected in series. The head reaction chamber has a first inlet, a first outlet, a first sludge return inlet, and a nitrified liquor return outlet. The tail reaction chamber has a second inlet, a second outlet, and a third sludge return inlet. A reaction chamber adjacent to the tail reaction chamber has a nitrified liquor return inlet. A reaction chamber between the tail reaction chamber and the head reaction chamber has a second sludge return inlet. Furthermore, the first outlet and the second outlet are connected to the inlet of the secondary sedimentation tank. The first sludge return... The inlet, the second sludge return inlet, and the third sludge return inlet are all connected to the sludge outlet of the secondary sedimentation tank. The nitrification liquid return outlet is connected to the nitrification liquid return inlet. When simulating AOA mode, the central control system controls the first inlet, the second outlet, the first sludge return inlet, and the second sludge return inlet to open, and the first outlet, the second inlet, the third sludge return inlet, the nitrification liquid return outlet, and the nitrification liquid return inlet to close. When simulating AAO mode, the central control system controls the second inlet, the first outlet, the third sludge return inlet, the nitrification liquid return inlet, and the nitrification liquid return outlet to open, and the first inlet, the second outlet, the first sludge return inlet, and the second sludge return inlet to close.

[0007] In some embodiments, eight reaction chambers are connected in series, arranged sequentially from beginning to end as the first reaction chamber, the second reaction chamber, the third reaction chamber, the fourth reaction chamber, the fifth reaction chamber, the sixth reaction chamber, the seventh reaction chamber, and the eighth reaction chamber. When simulating the AOA mode, the first and second reaction chambers are anaerobic zones, the third and fourth reaction chambers are aerobic zones, and the fifth, sixth, seventh, and eighth reaction chambers are anoxic zones. When simulating the AAO mode, the eighth reaction chamber is an anaerobic zone, the seventh, sixth, and fifth reaction chambers are anoxic zones, and the fourth, third, second, and first reaction chambers are aerobic zones.

[0008] In some embodiments, the fifth reaction chamber, the sixth reaction chamber, the seventh reaction chamber, and the eighth reaction chamber are all filled with polyurethane sponge filler.

[0009] In some embodiments, both the third and fourth reaction chambers are provided with modified honeycomb ceramic fillers that have been soaked in hydrochloric acid.

[0010] In some embodiments, adjacent reaction chambers are provided with lifting partitions, and when the lifting partitions are pulled out, the two adjacent reaction chambers are completely connected.

[0011] In some embodiments, agitators are provided at the top of the first reaction chamber, the second reaction chamber, the fifth reaction chamber, the sixth reaction chamber, the seventh reaction chamber, and the eighth reaction chamber, and an aeration device is provided at the bottom of the first reaction chamber, the second reaction chamber, the third reaction chamber, the fourth reaction chamber, and the fifth reaction chamber.

[0012] In some embodiments, a generator is also included. The secondary sedimentation tank is a vertical flow secondary sedimentation tank. The generator is located at the bottom outside the secondary sedimentation tank and has an impeller. The effluent from the vertical flow secondary sedimentation tank can flush the impeller.

[0013] In some embodiments, an emergency dosing rapid mixing tank is also included, the inlet of which is supplied with wastewater, and the outlet of which is connected to the first inlet and the second inlet.

[0014] In some embodiments, a water quality monitoring module and a qPCR monitoring module are also included. Both the water quality monitoring module and the qPCR monitoring module are electrically connected to the central control system. The water quality monitoring module has multiple detection probes, and detection probes are provided at the first water inlet, the second water inlet, and the reaction chamber. The sampling device of the qPCR monitoring module is located in each reaction chamber to quantitatively collect liquid samples.

[0015] In some embodiments, the secondary sedimentation tank includes an outer shell, a sludge hopper, a central inlet pipe, an outlet pipe, an overflow weir, a sludge return pipe, honeycomb inclined tube packing, and a support. The sludge hopper is fixedly disposed at the bottom of the outer shell, the sludge return pipe is connected to the bottom of the sludge hopper and extends out of the outer shell, the support is fixedly disposed inside the outer shell and located above the support, the support is used to fix the central inlet pipe, the baffle is fixedly disposed at the end of the central inlet pipe, the overflow weir is fixedly disposed above the sludge hopper, the honeycomb inclined tube packing has multiple inclined water pipes, the honeycomb inclined tube packing is fixedly disposed inside the outer shell and located between the overflow weir and the support, and the outlet pipe is fixedly disposed on the side wall of the outer shell and located close to the overflow weir.

[0016] The present invention achieves the following technical effects compared to the prior art: The dual-mode coupled PD / A wastewater denitrification device provided by this invention achieves mode switching through the on / off control of the dedicated inlet and outlet of the reaction chamber. The central control system can complete the overall switching of the influent, effluent, and return system of AOA / AAO modes by simply starting and stopping valves / pumps, without the need to reconstruct the internal structure of the reactor. The switching operation is convenient and has no redundant steps, solving the problem of poor adaptability of traditional single-mode devices. The two modes are specifically designed to cover different operating conditions: the AOA mode is suitable for wastewater with low carbon-to-nitrogen ratio, no additional phosphorus removal requirements, and low flow conditions, relying on dual sludge return to utilize endogenous carbon for denitrification without the need for external carbon sources; the AAO mode is suitable for wastewater with high carbon-to-nitrogen ratio, dual requirements for denitrification and phosphorus removal, and high flow / heavy rain impact conditions, relying on nitrification liquid return and sludge return to achieve synergistic denitrification and phosphorus release and uptake by polyphosphate-accumulating bacteria. One device meets the needs of all wastewater treatment scenarios, significantly reducing the cost of new construction / upgrading. The denitrification reactor adopts a design with multiple reaction chambers connected in series. The inlet and outlet of the influent, effluent, sludge return, and nitrification liquor return are precisely allocated to the head, tail, and adjacent reaction chambers. Each interface has a dedicated function and does not interfere with each other, avoiding pipeline crossings of multiple return / influent / effluent systems and reducing the difficulty of equipment installation and pipeline layout. The return system is precisely connected to the secondary sedimentation tank: all sludge return inlets are connected to the sludge outlet of the secondary sedimentation tank. The nitrification liquor return completes the closed loop from the nitrification liquor return outlet to the nitrification liquor return inlet only inside the reactor, without additional external equipment. This simplifies the overall process layout, and operation and maintenance personnel can quickly identify the function of each interface, reducing the difficulty of daily operation and troubleshooting. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the arrangement of the stirrer in some embodiments of the present invention; Figure 2 This is a schematic diagram showing the arrangement of the aeration device in some embodiments of the present invention; Figure 3 This is a schematic diagram of the generator structure in some embodiments of the present invention; Figure 4 This is a schematic diagram of the secondary sedimentation tank in some embodiments of the present invention; Figure 5 This is a schematic diagram of the structure of the honeycomb inclined tube packing in some embodiments of the present invention; Figure 6 This is a schematic diagram of the AOA mode in some embodiments of the present invention; Figure 7This is a schematic diagram of the AAO mode in some embodiments of the present invention; Figure 8 This is a schematic diagram of the dual-mode coupled PD / A wastewater denitrification device in some embodiments of the present invention; Figure 9 These are diagrams illustrating the long-term operation effect of AAO mode in some embodiments of the present invention; Figure 10 This is a schematic diagram comparing the processing performance of AAO and AOA at high C / N ratios in some embodiments of the present invention; Figure 11 This is a schematic diagram comparing the removal rates of various indicators of AAO and AOA at high C / N ratios in some embodiments of the present invention; Figure 12 This is a schematic diagram comparing the processing performance of AAO and AOA at low C / N ratios in some embodiments of the present invention; Figure 13 This is a schematic diagram comparing the removal rates of various indicators of AAO and AOA at low C / N in some embodiments of the present invention.

[0019] In the diagram: 1-First reaction chamber; 101-First inlet; 102-First sludge return inlet; 103-Nitrified liquor return outlet; 104-First outlet; 2-Second reaction chamber; 3-Third reaction chamber; 4-Fourth reaction chamber; 5-Fifth reaction chamber; 501-Second sludge return inlet; 6-Sixth reaction chamber; 7-Seventh reaction chamber; 701-Nitrified liquor return inlet; 8-Eighth reaction chamber; 801-Second outlet; 802-Second inlet; 803-Third sludge return outlet. 9-Inlet; 10-Aeration device; 11-Generator; 1101-Generator body; 1102-Containing cavity; 1103-Impeller; 1104-Inlet pipe; 1105-Outlet pipe; 12-Secondary sedimentation tank; 1201-Central inlet pipe; 1202-Overflow weir; 1203-Outlet pipe; 1204-Honeycomb inclined tube packing; 1205-Support; 1206-Baffle plate; 1207-Sludge hopper; 1208-Sludge return pipe; 13-Emergency dosing rapid mixing tank. Detailed Implementation

[0020] 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, and 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.

[0021] The purpose of this invention is to provide a dual-mode coupled PD / A wastewater denitrification device to solve the problems existing in the prior art. It has a dual-mode switching function and has a wide range of applicability.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figures 1-13 As shown, this invention provides a dual-mode coupled PD / A wastewater denitrification device, including a secondary sedimentation tank 12, a denitrification pilot reactor, and a central control system. The denitrification pilot reactor includes multiple reaction chambers connected in series. The head reaction chamber has a first inlet 101, a first outlet 104, a first sludge return inlet 102, and a nitrified liquor return outlet 103. The tail reaction chamber has a second inlet 802, a second outlet 801, and a third sludge return inlet 803. The reaction chamber adjacent to the tail reaction chamber has a nitrified liquor return inlet 701. A reaction chamber between the tail reaction chamber and the head reaction chamber has a second sludge return inlet 501. Furthermore, the first outlet 104 and the second outlet 801 are connected to the inlet of the secondary sedimentation tank 12. The first sludge return inlet 102 and the second sludge return inlet 501... The third sludge return inlet 803 is connected to the sludge outlet of the secondary sedimentation tank 12, and the nitrification liquid return outlet 103 is connected to the nitrification liquid return inlet 701. When simulating AOA mode, the central control system controls the first inlet 101, the second outlet 801, the first sludge return inlet 102 and the second sludge return inlet 501 to open, and the first outlet 104, the second inlet 802, the third sludge return inlet 803, the nitrification liquid return outlet 103 and the nitrification liquid return inlet 701 to close. When simulating AAO mode, the central control system controls the second inlet 802, the first outlet 104, the third sludge return inlet 803, the nitrification liquid return inlet 701 and the nitrification liquid return outlet 103 to open, and the first inlet 101, the second outlet 801, the first sludge return inlet 102 and the second sludge return inlet 501 to close.

[0024] The system achieves mode switching through dedicated inlet and outlet control of the reaction chamber. The central control system can complete the overall switching of the influent, effluent, and return system between AOA and AAO modes by simply starting and stopping valves / pumps, without the need to reconstruct the internal structure of the reactor. The switching operation is convenient and has no redundant steps, solving the problem of poor adaptability of traditional single-mode devices. The two modes are specifically designed to cover different operating conditions: the AOA mode is suitable for wastewater with low carbon-to-nitrogen ratio, no additional phosphorus removal requirements, and low flow conditions. It utilizes endogenous carbon for denitrification through dual sludge recirculation, eliminating the need for external carbon sources. The AAO mode is suitable for wastewater with high carbon-to-nitrogen ratio, dual requirements for denitrification and phosphorus removal, and high flow / heavy rain impact conditions. It achieves synergistic denitrification and phosphorus release and uptake by polyphosphate-accumulating bacteria through nitrification liquor recirculation and sludge recirculation. One device meets the needs of all wastewater treatment scenarios, significantly reducing the cost of new construction / upgrading. The denitrification reactor adopts a design of multiple series-connected reaction chambers, precisely allocating the inlet and outlet of the influent, effluent, sludge return, and nitrification liquor return to the head, tail, and adjacent reaction chambers. Each interface has its own function and does not interfere with each other, avoiding pipeline crossings of multiple return / influent / effluent systems and reducing the difficulty of equipment installation and pipeline layout. The return system is precisely connected to the secondary sedimentation tank 12: all sludge return inlets are connected to the sludge outlet of the secondary sedimentation tank 12, and the nitrification liquor return is completed in a closed loop from the nitrification liquor return outlet 103 to the nitrification liquor return inlet 701 within the reactor, without additional external equipment, simplifying the overall process layout. Maintenance personnel can quickly identify the function of each interface, reducing the difficulty of daily operation and troubleshooting. The short-cut denitrification-anaerobic ammonium oxidation (PD / A) process is used as the core nitrogen removal support in the dual-mode system, rather than as an independent process. It leverages the zoned reaction environment of AOA / AAO to provide a stable substrate supply and microbial enrichment environment for PD / A. In AAO mode, nitrification liquor recirculation provides sufficient nitrate nitrogen for PD / A, the aerobic zone completes short-cut nitrification to produce nitrite nitrogen, and the anoxic zone achieves synergistic short-cut denitrification and anaerobic ammonium oxidation, alleviating the carbon source competition problem of traditional AAO and improving the nitrogen removal efficiency of low C / N ratio wastewater. In AOA mode, dual sludge recirculation introduces endogenous carbon and microorganisms into PD / A, and the anoxic zone provides a stable environment for the enrichment of anaerobic ammonium oxidizing bacteria, achieving highly efficient autotrophic nitrogen removal without external carbon sources and solving the problem of insufficient nitrogen removal efficiency in traditional AOA. Compared with the traditional single-mode coupled PD / A process, this device allows the PD / A process to achieve optimal nitrogen removal effect in both AOA and AAO frameworks, with nitrogen removal efficiency far exceeding that of conventional AAO / AOA devices.

[0025] Furthermore, in AOA mode, only the first and second sludge recirculations are activated, while the nitrification liquor recirculation is deactivated. This replenishes the microbial concentration within the reactor through sludge recirculation, ensuring bacterial activity, and utilizes the endogenous carbon introduced by the sludge recirculation to enhance denitrification. No external carbon source is required, and there is no power consumption from nitrification liquor recirculation, significantly reducing operating energy consumption and reagent costs, thus meeting the energy-saving treatment needs of low C / N ratio wastewater. In AAO mode, the third sludge recirculation and nitrification liquor recirculation are activated. Sludge recirculation ensures the concentration of polyphosphate-accumulating bacteria and denitrifying bacteria, while a high proportion of nitrification liquor recirculation provides sufficient nitrate substrate for denitrification / PD / A reactions in the anoxic zone, ensuring dual nitrogen and phosphorus removal effects. Moreover, the nitrification liquor recirculation is a closed loop within the reactor, with recirculation energy consumption far lower than that of an external recirculation system. The on-demand activation / deactivation of the recirculation system avoids the ineffective energy consumption of continuous operation of traditional recirculation systems, achieving precise control of energy consumption and carbon source, aligning with the industry's needs for energy conservation, emission reduction, and standard improvement in wastewater treatment.

[0026] In some embodiments, eight reaction chambers are connected in series, and from beginning to end are the first reaction chamber 1, the second reaction chamber 2, the third reaction chamber 3, the fourth reaction chamber 4, the fifth reaction chamber 5, the sixth reaction chamber 6, the seventh reaction chamber 7, and the eighth reaction chamber 8. When simulating the AOA mode, the first reaction chamber 1 and the second reaction chamber 2 are anaerobic zones, the third reaction chamber 3 and the fourth reaction chamber 4 are aerobic zones, and the fifth reaction chamber 5, the sixth reaction chamber 6, the seventh reaction chamber 7, and the eighth reaction chamber 8 are anoxic zones. When simulating the AAO mode, the eighth reaction chamber 8 is an anaerobic zone, the seventh reaction chamber 7, the sixth reaction chamber 6, and the fifth reaction chamber 5 are anoxic zones, and the fourth reaction chamber 4, the third reaction chamber 3, the second reaction chamber 2, and the first reaction chamber 1 are aerobic zones. Based on the core zoning sequence of the AOA and AAO modes (Anaerobic-Aerobic-Anoxic (AOA) and AAO-Anoxic-Aerobic (AAO) modes), the eight reaction chambers are quantitatively and modularly divided into functional zones. The volume ratio and number of chambers are perfectly adapted to the hydraulic retention time (HRT) requirements of both modes, ensuring a high degree of consistency between the microbial metabolism and biochemical reactions in each functional zone and the number of chambers. In the AOA mode, the ratio of anaerobic:aerobic:anoxic is 1:1:2, with a 2:2:4 chamber ratio (Reaction Chamber 1, Reaction Chamber 2 (anaerobic), Reaction Chamber 3, Reaction Chamber 4 (aerobic), Reaction Chamber 5, Reaction Chamber 6, Reaction Chamber 7, Reaction Chamber 8 (anoxic)). Four extra-large chambers are reserved for the anoxic zone, which meets the needs of the AOA mode, which relies on endogenous carbon denitrification and the enrichment of anaerobic ammonia oxidizing bacteria. The sufficient retention time in the anoxic zone allows the core short-cut denitrification-anaerobic ammonia oxidation (PD / A) reaction to proceed fully, significantly improving nitrogen removal efficiency. The AAO (Anaerobes-Anaerobic-Aerobic) reactor is configured with an anaerobic:anoxic:aerobic ratio of 1:3:4, distributed in a 1:3:4 ratio of compartments (8th reaction chamber - anaerobic, 5th reaction chamber - 5, 6th reaction chamber - 6, 7th reaction chamber - 7 anoxic, 1st reaction chamber - 1, 2nd reaction chamber - 2, 3rd reaction chamber - 3, 4th reaction chamber - 4th reaction chamber - aerobic). This design ensures a strictly anaerobic environment for phosphorus release by polyphosphate-accumulating organisms (PAOs) through one independent anaerobic compartment, meets the substrate conversion requirements for denitrification / PD / A (phosphorus-accumulating phosphorus) through three anoxic compartments, and achieves the dual functions of ammonia nitrification and PAOs' excessive phosphorus uptake through four extra-large aerobic compartments, aligning with the core objective of the AAO reactor: simultaneous nitrogen and phosphorus removal. Standardized series-connected compartments eliminate hydraulic dead zones: The eight-compartment series layout of equal specifications allows for a uniform flow pattern within the reactor. The flow velocity and mixing effect in each compartment can be precisely controlled, avoiding localized hydraulic dead zones caused by uneven compartment sizes. This ensures sufficient contact between wastewater and activated sludge / packing materials, improving mass transfer and reaction efficiency. The specific denitrification pilot reactor is 6 meters long, 1.8 meters wide, and 2.4 meters high, divided into 8 compartments, each 1.5 meters long and 0.9 meters wide, with a total hydraulic retention time of 12 hours, and is constructed entirely of carbon steel.

[0027] In some embodiments, reaction chambers 5, 6, 7, and 8 are all filled with polyurethane sponge packing. Because anaerobic ammonia oxidizing bacteria grow slowly and require a long sludge retention time to achieve enrichment, they can easily conflict with the designed sludge retention time of other microorganisms in mainstream reactors. This product utilizes anaerobic ammonia oxidizing bacteria provided by an auxiliary sludge cultivation device as the initial inoculum and adds polyurethane sponge packing in the anoxic zone, aiming to ensure that AnAOB (AnAOB) can remain on the polyurethane sponge packing. Through long-term operation, the addition of anaerobic ammonia oxidizing bacteria can be reduced or even eliminated, achieving a certain degree of enrichment or maintaining abundance. In AOA mode, reaction chambers 5 to 8 are entirely anoxic zones, the core reaction zones of the PD / A process. The polyurethane sponge packing directly provides an attachment carrier for anaerobic ammonia oxidizing bacteria and short-range denitrifying bacteria, facilitating efficient nitrogen removal. In the AAO (Anaerobic / Anoxic) mode, reaction chambers five to seven are anoxic zones, and reaction chamber eight is an anaerobic zone. Polyurethane sponge packing serves as the attachment point for denitrifying bacteria in chambers five to seven, and in chamber eight, it retains sludge and enhances the retention of microorganisms in the anaerobic zone. No section of the polyurethane sponge packing is idle, achieving efficient utilization of both reactor space and the function of the polyurethane sponge packing. Polyurethane sponge packing possesses high porosity, large specific surface area, and biocompatibility, making it an excellent attachment carrier for core microbial communities in the PD / A process, such as anaerobic ammonia oxidizing bacteria and short-cut denitrifying bacteria. These microbial communities have long generation cycles and are easily lost with sludge. Filling reaction chambers five to eight with this polyurethane sponge packing achieves in-situ directional enrichment and stable retention of the microbial communities: providing a dedicated survival carrier for anaerobic ammonia oxidizing bacteria. Anaerobic ammonia oxidizing bacteria grow extremely slowly and cannot stably persist in suspended sludge systems. The porous structure of the polyurethane sponge allows them to form a stable biofilm inside the polyurethane sponge packing, eliminating the risk of suspended sludge loss and achieving long-term enrichment, gradually improving their performance in the reactor. The abundance of microbial communities enhances the autotrophic nitrogen removal effect of the PD / A process; enriching short-range denitrifying bacteria improves substrate conversion efficiency: after short-range denitrifying bacteria attach to the surface of polyurethane sponge packing, they can form high-concentration bacterial aggregates, significantly improving their conversion efficiency of nitrate nitrogen, rapidly reducing nitrate nitrogen to nitrite nitrogen, and stably supplying core substrates for anaerobic ammonia oxidation bacteria, achieving efficient synergy between short-range denitrification and anaerobic ammonia oxidation; forming a synergistic microbial community system: the porous structure of polyurethane sponge packing allows different denitrifying bacteria to attach in layers at different pore levels, avoiding substrate competition between microbial communities, while creating a stable microenvironment, allowing denitrification and PD / A reactions to proceed in an orderly manner.

[0028] In some embodiments, both the third reaction chamber 3 and the fourth reaction chamber 4 are equipped with modified honeycomb ceramic packing material soaked in hydrochloric acid. Two common nitrifying bacteria exist in the aerobic zone: AOB (ammonia oxidizing bacteria) and NOB (nitrite oxidizing bacteria). AOB oxidizes ammonia nitrogen in the water to nitrite nitrogen, while NOB oxidizes nitrite nitrogen in the water to nitrate nitrogen. Nitrite nitrogen is a substrate required for the growth of anaerobic ammonia oxidizing bacteria, and a stable supply of nitrite nitrogen is crucial for the enrichment of anaerobic ammonia oxidizing bacteria. Therefore, adding modified honeycomb ceramic packing material to the aerobic zone enables a certain accumulation of nitrite nitrogen in the aerobic zone under AOA mode, thereby synergistically supplying the substrate for anaerobic ammonia oxidizing bacteria growth with short-range denitrification in the anoxic zone, promoting the enrichment of anaerobic ammonia oxidizing bacteria.

[0029] For modified honeycomb ceramic fillers, an alkaline positive charge modification method is used: the honeycomb ceramic is impregnated with a 1-3 mol / L HCl solution at room temperature for 2-4 hours, followed by washing and drying. This causes the filler surface to adsorb a large amount of H+, forming a negatively charged surface. In a neutral aquatic environment, AOB bacteria (weakly positively charged cell walls) are electrostatically attracted to the ceramic surface, while NOB bacteria (weakly negatively charged cell walls) are electrostatically repelled, thus directly reducing the initial adhesion rate of NOB. Simultaneously, due to the porous structure of the honeycomb ceramic itself, localized anoxic / anaerobic regions are easily formed. NOB has poor tolerance to low DO environments, while AOB has relatively good tolerance. Therefore, adding honeycomb ceramic fillers can, to a certain extent, enrich AOB bacteria and inhibit NOB bacteria. Through the dual effects of electrostatic screening and low DO inhibition, the third and fourth reaction chambers can only achieve short-range nitrification reactions from ammonia nitrogen to nitrite nitrogen, avoiding NOB from further oxidizing nitrite nitrogen to nitrate nitrogen. This allows the effluent from the aerobic zone to stably carry high concentrations of nitrite nitrogen into the subsequent anoxic zone, providing a continuous and stable substrate supply for the anaerobic ammonia oxidation reaction of the PD / A process. This is the core technical support for the deep coupling of the PD / A process and the dual-mode process.

[0030] In some embodiments, adjacent reaction chambers are equipped with pull-up partitions. Removing the pull-up partitions completely connects the two adjacent reaction chambers. The partitions within the reactor for zoning employ a pull-up design. Guide rails are installed on the denitrification pilot reactor, and the partitions are inserted into the reactor along the guide rails. When the volume ratio of the zones needs to be adjusted, it can be adjusted by removing the corresponding partition. For example, with high C / N ratios, it is necessary to increase the volume of the anaerobic / anoxic zone. The partition at the end of the original anaerobic or anoxic zone can be removed, and the subsequent anoxic and aerobic zone volumes can be allocated to the anaerobic / anoxic zone. With low C / N water quality, the volume of the aerobic zone can be appropriately increased to enhance short-cut nitrification and stably supply nitrite nitrogen to the PD / A process. Simultaneously, through precise control of the anoxic zone volume, the utilization efficiency of endogenous carbon is maximized without the need for additional carbon sources. Under high phosphorus loads, the volume of the anaerobic zone is expanded separately to provide more reaction time for phosphorus-accumulating bacteria to release phosphorus, thereby improving the efficiency of excessive phosphorus uptake in the subsequent aerobic zone and ensuring that phosphorus removal meets standards. This is suitable for scenarios with fluctuating phosphorus loads, such as municipal wastewater. The lift-up baffle does not change the core zoning logic of AOA / AAO, but rather enables fine-tuning of the volume of each functional zone within the dual-mode framework. This allows both modes to be further optimized according to actual operating conditions (such as high flow rates during heavy rain, low flow rates during drought, and sudden changes in pollutant load), significantly improving the applicability and treatment effect of the dual modes. AOA mode optimization: For wastewater with extremely low C / N ratios, the baffle at the front end of the anoxic zone can be removed to expand the volume of the anoxic zone, prolonging the contact time between anaerobic ammonia oxidizing bacteria and the substrate, and enhancing the PD / A autotrophic denitrification effect. If the influent ammonia nitrogen concentration is high, the volume of the aerobic zone can be appropriately expanded to improve short-cut nitrification efficiency and ensure nitrite nitrogen supply. AAO mode optimization: During periods of heavy rainfall with large influent flow and sufficient carbon source, the baffle in the anaerobic / anoxic zone can be removed to expand its volume, avoiding insufficient phosphorus release and low denitrification efficiency due to insufficient hydraulic retention time. During periods of drought with small influent flow and insufficient carbon source, the anaerobic zone can be reduced and the anoxic zone expanded to improve carbon source utilization. Transition optimization for dual-mode switching: During mode switching, the volume of each functional zone can be finely adjusted by lifting the baffle to buffer changes in the process environment (such as DO and substrate concentration), avoiding a decrease in bacterial activity due to sudden changes in volume, and ensuring the smoothness of mode switching.

[0031] In some embodiments, agitators 9 are installed at the top of the first reaction chamber 1, the second reaction chamber 2, the fifth reaction chamber 5, the sixth reaction chamber 6, the seventh reaction chamber 7, and the eighth reaction chamber 8, and aeration devices 10 are installed at the bottom of the first reaction chamber 1, the second reaction chamber 2, the third reaction chamber 3, the fourth reaction chamber 4, and the fifth reaction chamber 5. The agitators 9 are only arranged in the dual-mode full-range anaerobic / anoxic zone. The first reaction chamber 1, the second reaction chamber 2 (AOA anaerobic zone / AAO aerobic zone, with the core being the AOA anaerobic zone, and emergency agitation is possible in AAO mode), and the fifth to eighth reaction chambers (AOA full-range anoxic zone / AAO anoxic and anaerobic zone) are the core range of anaerobic / anoxic in the dual-mode. Arranging the agitators 9 here only achieves water mixing and sludge suspension without introducing any molecular oxygen, precisely maintaining the low DO environment of the anaerobic / anoxic zone. Aeration devices 10 are only located in the core aerobic zone and emergency positions in the anaerobic / anoxic zone of the dual-mode system. Reaction chambers 1 through 4 are shared core aerobic zones for both modes (AOA dedicated aerobic zone and the core section of the AAO aerobic zone). Reaction chamber 4 is always an aerobic zone. Reaction chamber 5 is adjacent to reaction chamber 4, where aeration devices 10 are located. They can be activated or deactivated as needed. When the volume of the aerobic zone needs to be expanded, the partition between reaction chamber 4 and reaction chamber 5 needs to be removed, combining them into a single aerobic zone. At this point, the aeration devices in reaction chamber 5 can be put into use. The arrangement of agitator 9 and aeration devices 10 covers the process requirements of both modes under AOA / AAO dual-mode. The same set of equipment can perform its corresponding functions in different modes, with no equipment idle due to mode switching, significantly improving equipment utilization and avoiding waste of hardware resources.

[0032] In some embodiments, the dual-mode coupled PD / A wastewater denitrification device further includes a generator 11, a secondary sedimentation tank 12 is a vertical flow secondary sedimentation tank 12, the generator 11 is located at the bottom outside the secondary sedimentation tank 12, the generator 11 has an impeller 1103, and the effluent from the vertical flow secondary sedimentation tank 12 can flush the impeller 1103. The specific generator 11 includes an inlet pipe 1104, an outlet pipe 1105, a receiving cavity 1102, an impeller 1103, and a generator body 1101. The impeller 1103 is rotatably disposed in the receiving cavity 1102, and the shaft of the impeller 1103 is fixedly connected to the rotor of the generator body 1101. The inlet pipe 1104 is fixedly disposed at the top of the receiving cavity 1102 and communicates with the receiving cavity 1102. The outlet pipe 1105 is fixedly disposed at the side of the receiving cavity 1102 and communicates with the receiving cavity 1102. Liquid enters the receiving cavity 1102 through the inlet pipe 1104 and washes the impeller 1103, and then is discharged from the outlet pipe 1105. The water falling from the height of the secondary sedimentation tank 12 has a certain gravitational potential energy, which is converted into kinetic energy during the fall. The kinetic energy impacts the impeller 1103 of the energy conversion device, causing it to rotate. The impeller 1103 is connected to the generator body 1101 through a drive shaft. The impeller 1103, which is impacted and rotated, drives the generator 11 through the drive shaft, thereby realizing the effect of converting gravitational potential energy into electrical energy, thus providing a certain power supply for the instruments of the entire system.

[0033] In some embodiments, the dual-mode coupled PD / A wastewater denitrification device further includes an emergency dosing rapid mixing tank 13. The inlet of the emergency dosing rapid mixing tank 13 is for wastewater inflow, and the outlet of the emergency dosing rapid mixing tank 13 is connected to the first inlet 101 and the second inlet 802. Wastewater inflow (especially municipal domestic sewage) is easily affected by pipe network drainage, seasonal changes, and residents' water usage habits, resulting in problems such as fluctuating flow rates and sudden increases and decreases in pollutant concentrations. As a front-end pretreatment unit, the emergency dosing rapid mixing tank 13 can regulate the inflow and homogenize the water quality, keeping the water flow entering the denitrification reactor stable and preventing water quality / flow fluctuations from directly impacting the functional bacteria and process environment within the reactor. Sudden high-load shocks to wastewater inflow (such as direct discharge of high-concentration wastewater into the pipe network or a sudden increase in wastewater pollutants during holidays) and shocks from toxic and harmful substances (such as industrial wastewater leakage or excessive discharge of detergents / disinfectants) are the main causes of reactor microbial inactivation and a sharp drop in treatment efficiency. The mixing tank, as a pre-buffer barrier, can significantly reduce shock loads and protect the core functional microbial community in the reactor (especially slow-growing anaerobic ammonia oxidizing bacteria and AOB bacteria).

[0034] In some embodiments, the dual-mode coupled PD / A wastewater denitrification device further includes a water quality monitoring module and a qPCR monitoring module. Both the water quality monitoring module and the qPCR monitoring module are electrically connected to the central control system. The water quality monitoring module has multiple detection probes. Detection probes are installed at the first inlet 101, the second inlet 802, and the reaction chamber. The detection probes monitor parameters such as ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, and DO in the reactor water in real time, thereby intelligently adjusting the internal and external reflux ratio and the influent flow rate, and adjusting the reactor C / N ratio to maintain a suitable environment for timely and accurate partial denitrification, which is beneficial for the substrate supply of anaerobic ammonia oxidizing bacteria. This includes probes at the reactor inlet and probes at the reactor anoxic zone. The anoxic zone probe is mainly used to monitor the C / N ratio in the anoxic zone, thereby automatically adjusting the internal and external reflux ratio to a suitable range for PD / A reaction. The inlet probe mainly monitors the C / N ratio of the influent water, thereby controlling the intelligent switching of the two modes of the reactor, that is, switching to AOA mode when C / N is low and switching to AAO mode when C / N is high. The sampling device of the qPCR monitoring module is set in each reaction chamber to quantitatively collect liquids. The central control system has a built-in real-time fluorescence quantitative PCR analyzer, which realizes the analysis and detection of nucleic acids through rapid temperature-switching amplification, real-time fluorescence signal acquisition and software data processing, thereby determining the abundance of microbial communities.

[0035] In some embodiments, the secondary sedimentation tank 12 includes an outer shell, a sludge hopper 1207, a central inlet pipe 1201, an outlet pipe 1203, an overflow weir 1202, a sludge return pipe 1208, honeycomb inclined tube packing 1204, and a support 1205. The sludge hopper 1207 is fixedly disposed at the bottom of the outer shell, the sludge return pipe 1208 is connected to the bottom of the sludge hopper 1207 and extends out of the outer shell, and the support 1205 is fixedly disposed inside the outer shell and located above the support 1205. 205 is used to fix the central inlet pipe 1201. The baffle plate 1206 is fixedly installed at the end of the central inlet pipe 1201. The overflow weir 1202 is fixedly installed above the sludge hopper 1207. The honeycomb inclined tube packing 1204 has multiple inclined water pipes. The honeycomb inclined tube packing 1204 is fixedly installed inside the shell and located between the overflow weir 1202 and the support 1205. The outlet pipe 1203 is fixedly installed on the side wall of the shell and close to the overflow weir 1202. The effluent from the nitrogen reactor enters from the center of the top of the tank through the central inlet pipe 1201. The water flow radiates evenly in all directions and flows vertically downward along the tank (upward flow), keeping the water flow velocity and pollutant concentration in each area of ​​the tank uniform, avoiding excessively fast local water flow from impacting the sludge layer, and ensuring that the suspended sludge has sufficient time to complete gravity settling. The baffle 1206 at the end of the central inlet pipe 1201 quickly dissipates the vertical kinetic energy of the incoming water, changing the flow from an impact flow to a slow flow. This prevents the high-speed incoming water from impacting the sludge layer at the bottom of the tank, causing sludge to churn and become suspended. It also prevents the settled sludge from being carried back to the outlet by the water flow, ensuring the basic effect of solid-liquid separation. The honeycomb inclined tube packing 1204 divides the core sedimentation zone into numerous parallel shallow channels. The settling distance of sludge particles is shortened from the height of the tank to the diameter of the inclined tube, significantly reducing settling time. Even tiny activated sludge flocs can settle quickly within the channels. Specifically, the sludge hopper 1207 is a conical sludge hopper. The inclined wall of the conical sludge hopper allows the sludge settled at the bottom of the tank to quickly converge towards the center of the hopper 1207 under gravity. Compared to a flat-bottomed tank, sludge collection efficiency is greatly improved, avoiding anaerobic fermentation and sludge floating problems caused by large-scale sludge accumulation at the bottom of the tank. Secondary sedimentation tank 12 is a vertical flow secondary sedimentation tank, 3m high and 2m in diameter, with a sludge retention time of 4 hours. The honeycomb inclined tube packing material 1204 is 1m high and tilted at a 60° angle to improve sedimentation efficiency.

[0036] Specific case studies are as follows: The influent is domestic sewage, and the daily treatment capacity is 40m³. 3 The hydraulic retention time is 12 hours. The influent enters the emergency dosing-rapid mixing tank, and after homogenization, it enters the reactor for biological treatment. After treatment, it enters the secondary sedimentation tank 12. After sedimentation, the supernatant enters the drainage pipe through the effluent weir of the secondary sedimentation tank 12 and is discharged from the system.

[0037] Select AOA mode on the central control system panel and click automatic operation. The reactor will then operate in AOA mode. When the reactor is running in AOA mode, the anaerobic / aerobic / anoxic HRT ratio is 1:1:2, meaning the first and second reactor compartments are anaerobic zones, the third and fourth reactor compartments are aerobic zones, and the eighth, seventh, sixth, and fifth reactor compartments are anoxic zones. Water enters through the first inlet 101 at the first reactor compartment and exits through the second outlet 801 at the eighth reactor compartment. Wastewater enters sequentially from the inlet pipe at the first reactor compartment into the first and second anaerobic reactors. Then, it flows through the overflow ports on the reactor walls into the third and fourth aerobic reactors. Next, it flows through the overflow ports on the reactor walls into the fifth, sixth, seventh, and eighth anoxic reactors. Finally, it is pumped to the secondary settling tank 12 via the second outlet 801 at the eighth reactor compartment. From there, it enters the sedimentation zone through the central pipe of the secondary settling tank 12 for sedimentation. The supernatant from the sedimentation in the secondary settling tank 12 flows through an overflow weir into the drain pipe and is discharged from the system. The first sludge return inlet 102 and the second sludge return inlet 501 of the AOA system are activated. The sludge return ratios for both the first and second sludge return systems are 100%. Specifically: the first sludge return is initiated by a sludge return pump from the sludge hopper 1207 at the bottom of the secondary sedimentation tank 12, which is then returned to the anaerobic zone, i.e., the first reactor compartment, via the first sludge return pipe 1208. This is mainly used to replenish the microbial concentration in the reactor. The second sludge return is initiated by a sludge return pump from the sludge hopper 1207 at the bottom of the secondary sedimentation tank 12, which is then returned to the anoxic zone, i.e., the fifth reactor compartment, via the second sludge return pipe 1208. This not only replenishes the microbial concentration but also introduces the cell putrefaction products in the secondary sedimentation tank 12 as a carbon source, thereby enhancing the denitrification effect and reducing the impact of dissolved oxygen on the anoxic zone.

[0038] Select AAO mode on the central control system panel and click automatic operation. The reactor will then operate in AAO mode. When the reactor is running in AAO mode, the anaerobic / anoxic / aerobic HRT ratio is 1:3:4, meaning the eighth reactor compartment is the anaerobic zone, the seventh, sixth, and fifth reactor compartments are the anoxic zones, and the fourth, third, second, and first reactor compartments are the aerobic zones. Water enters through the inlet pipe at the eighth reactor compartment and exits through the first outlet (104) at the first reactor compartment. Wastewater enters the anaerobic zone's eighth reactor through the second inlet 802 in the eighth reactor compartment. It then flows sequentially through the overflow ports on the reactor wall into the seventh, sixth, and fifth anoxic zone reactors. Following this, it flows sequentially through the overflow ports on the reactor wall into the fourth, third, second, and first aerobic zone reactors. Finally, it is pumped to the secondary settling tank 12 through the first outlet 104 in the first aerobic zone reactor compartment. From there, it enters the sedimentation zone through the central pipe of the secondary settling tank 12 for sedimentation. The supernatant from the sedimentation in the secondary settling tank 12 flows through an overflow weir into the drainage pipe and is discharged from the system. The AAO third sludge return inlet 803 and nitrification liquor return are activated, with a designed sludge return ratio of 100% and a designed nitrification liquor return ratio of 200%. Specifically: AAO sludge return is initiated from the secondary settling tank 12, where sludge from the bottom sludge hopper 1207 of the secondary settling tank 12 is returned to the eighth reactor in the anaerobic zone via the sludge return pump and AAO sludge return pipe 1208 to replenish the sludge concentration in the reactor; nitrification liquor return is initiated from the end of the aerobic zone via the nitrification liquor return pump and nitrification liquor return pipe to the seventh reactor in the anoxic zone to provide nitrate nitrogen for denitrification and partial denitrification in the anoxic zone.

[0039] Adjust the sludge concentration in the reactor to keep it between 4000 and 5000 mg / L.

[0040] By adjusting the opening of the gas flow meter valve on the aeration pipe of each reaction cell, the aeration rate is adjusted so that the gas-water ratio is controlled at around 4.

[0041] The flow rate of all pipes in the reactor can be adjusted by valves installed on them, and the real-time flow rate and cumulative flow rate are displayed by electronic flow meters.

[0042] When it is necessary to empty the liquid in a certain cell, the emptying pipe valve at the bottom of the corresponding cell is opened to achieve the emptying, so as to facilitate maintenance and control.

[0043] Comparison of effects: The reactor operates in AAO mode for an extended period, with an influent flow rate of 1.66 m³ / h. 3 / h, with an outflow rate of 1.66m³ / h. 3The reactor operates at a rate of / h, with a sludge return ratio of 100%, a nitrification liquor return ratio of 200%, an air-to-water ratio of 6.7:1, a hydraulic retention time of 12 hours, and a volumetric distribution ratio of anaerobic:anoxic:aerobic of 1:3:4. The long-term operating performance of the reactor is as follows: Figure 9 As shown.

[0044] like Figures 10-11 The diagram illustrates the functional differences between the AOA and AAO modes of this invention, specifically the differences in treatment effects for wastewater with varying C / N ratios. In this study, the reactor was switched to AOA mode and operated for a period of time. High and low C / N periods were selected and compared with similar C / N periods in the AAO mode to assess the differences in treatment effectiveness. When the C / N ratio was around 5, the differences between the AAO and AOA modes were compared. At this point, the carbon source was sufficient, and the activity of denitrifying bacteria was high. Even a shorter anoxic retention time could achieve good nitrogen removal. Furthermore, because the AAO mode has a longer aerobic phase, its ability to remove ammonia nitrogen and recalcitrant COD is higher than that of the AOA mode.

[0045] like Figures 12-13 As shown, when the C / N ratio is around 2.5, carbon sources are scarce, denitrifying bacteria activity is low, and denitrification performance is poor in the AAO mode. In contrast, the AOA mode, on the one hand, provides endogenous carbon for denitrification in both the anoxic and anaerobic zones due to the presence of dual sludge recirculation; on the other hand, the AOA mode has a longer residence time in the anoxic zone, which is more conducive to denitrification.

[0046] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A dual-mode coupled PD / A wastewater denitrification device, characterized in that: The system includes a secondary sedimentation tank, a pilot-scale denitrification reactor, and a central control system. The pilot-scale denitrification reactor comprises multiple reaction chambers connected in series. The head reaction chamber has a first inlet, a first outlet, a first sludge return inlet, and a nitrified liquor return outlet. The tail reaction chamber has a second inlet, a second outlet, and a third sludge return inlet. A reaction chamber adjacent to the tail reaction chamber has a nitrified liquor return inlet. A reaction chamber between the head and tail reaction chambers has a second sludge return inlet. The first and second outlets are connected to the inlet of the secondary sedimentation tank. The first, second, and third sludge return inlets are all connected to the sludge outlet of the secondary sedimentation tank. The nitrification liquid return outlet is connected to the nitrification liquid return inlet. When simulating AOA mode, the central control system controls the first inlet, second outlet, first sludge return inlet, and second sludge return inlet to open, and the first outlet, second inlet, third sludge return inlet, nitrification liquid return outlet, and nitrification liquid return inlet to close. When simulating AAO mode, the central control system controls the opening of the second inlet, the first outlet, the third sludge return inlet, the nitrification liquid return inlet, and the nitrification liquid return outlet, and closes the first inlet, the second outlet, the first sludge return inlet, and the second sludge return inlet.

2. The dual-mode coupled PD / A wastewater denitrification device according to claim 1, characterized in that: The reaction chambers are arranged in series, consisting of eight chambers, from beginning to end: first reaction chamber, second reaction chamber, third reaction chamber, fourth reaction chamber, fifth reaction chamber, sixth reaction chamber, seventh reaction chamber, and eighth reaction chamber. When simulating AOA mode, the first and second reaction chambers are anaerobic zones, the third and fourth reaction chambers are aerobic zones, and the fifth, sixth, seventh, and eighth reaction chambers are anoxic zones. When simulating AAO mode, the eighth reaction chamber is an anaerobic zone, the seventh, sixth, and fifth reaction chambers are anoxic zones, and the fourth, third, second, and first reaction chambers are aerobic zones.

3. The dual-mode coupled PD / A wastewater denitrification device according to claim 2, characterized in that: The fifth, sixth, seventh, and eighth reaction chambers are all filled with polyurethane sponge filler.

4. The dual-mode coupled PD / A wastewater denitrification device according to claim 2, characterized in that: Both the third and fourth reaction chambers are equipped with modified honeycomb ceramic fillers that have been soaked in hydrochloric acid.

5. The dual-mode coupled PD / A wastewater denitrification device according to claim 1, characterized in that: The adjacent reaction chambers are equipped with lifting partitions. When the lifting partitions are pulled out, the two adjacent reaction chambers are completely connected.

6. The dual-mode coupled PD / A wastewater denitrification device according to claim 2, characterized in that: A stirrer is provided at the top of each of the first, second, fifth, sixth, seventh, and eighth reaction chambers, and an aeration device is provided at the bottom of each of the first, second, third, fourth, and fifth reaction chambers.

7. The dual-mode coupled PD / A wastewater denitrification device according to claim 1, characterized in that: It also includes a generator. The secondary sedimentation tank is a vertical flow secondary sedimentation tank. The generator is located at the bottom outside the secondary sedimentation tank. The generator has an impeller. The effluent from the vertical flow secondary sedimentation tank can flush the impeller.

8. The dual-mode coupled PD / A wastewater denitrification device according to claim 1, characterized in that: It also includes an emergency dosing rapid mixing tank, the inlet of which is supplied with wastewater, and the outlet of which is connected to the first inlet and the second inlet.

9. The dual-mode coupled PD / A wastewater denitrification device according to claim 1, characterized in that: It also includes a water quality monitoring module and a qPCR monitoring module. Both the water quality monitoring module and the qPCR monitoring module are electrically connected to the central control system. The water quality monitoring module has multiple detection probes. Detection probes are installed at the first water inlet, the second water inlet, and the reaction chamber. The sampling device of the qPCR monitoring module is installed in each reaction chamber to quantitatively collect liquid samples.

10. The dual-mode coupled PD / A wastewater denitrification device according to claim 1, characterized in that: The secondary sedimentation tank includes an outer shell, a sludge hopper, a central inlet pipe, a baffle plate, an outlet pipe, an overflow weir, a sludge return pipe, honeycomb inclined tube packing, and a support. The sludge hopper is fixedly installed at the bottom of the outer shell. The sludge return pipe is connected to the bottom of the sludge hopper and extends out of the outer shell. The support is fixedly installed inside the outer shell and located above the support, and the support is used to fix the central inlet pipe. The baffle plate is fixedly installed at the end of the central inlet pipe. The overflow weir is fixedly installed above the sludge hopper. The honeycomb inclined tube packing has multiple inclined water pipes. The honeycomb inclined tube packing is fixedly installed inside the outer shell and located between the overflow weir and the support. The outlet pipe is fixedly installed on the side wall of the outer shell and located close to the overflow weir.

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