Combined denitrification process method and device

Abstract

The invention provides a combined denitrification process method and device, and relates to the technical field of biological sewage treatment.The method comprises the steps that flocculent sludge of a sewage plant is introduced into a one-step PN / A reactor, PN / A granular sludge is formed under condition constraints, the one-step PN / A reactor with the sludge state being granular sludge is used for carrying out short-cut nitrification reaction, and PN / A reactor effluent is obtained; introducing the effluent of the PN / A reactor into a PD reactor, adding an organic carbon source into the PD reactor for short-cut denitrification to obtain the effluent of the PD reactor, introducing the effluent of the PD reactor into an Anammox reactor for deep denitrification to obtain the effluent of the Anammox reactor, and discharging the effluent of the Anammox reactor from an effluent storage tank. The technical problems that in the prior art, a large number of carbon sources need to be additionally added for supporting in the nitrification and denitrification process, the energy consumption in the treatment process is high, and the residual sludge yield is large are solved, and the technical effects of reducing the dosage of the organic carbon sources, reducing the sewage denitrification energy consumption and reducing the residual sludge amount are achieved.

Description

Technical Field

[0001] The present application relates to the technical field of biological sewage treatment, and in particular to a combined denitrification process method and device. Background Art

[0002] In the treatment of urban sewage and industrial wastewater, denitrification is a key link in ensuring the ecological safety of water bodies and preventing eutrophication of the aquatic environment. Conventional denitrification processes usually adopt the "nitrification-denitrification" pathway. First, ammonia nitrogen is oxidized to nitrate or nitrite through the nitrification process under aerobic conditions. Then, in an anoxic environment, an organic carbon source is used as an electron donor to reduce the nitrate to nitrogen gas to achieve nitrogen removal. However, in order to maintain reaction efficiency and ensure the removal of total nitrogen, the traditional nitrification / denitrification process requires the addition of a large amount of organic carbon source (such as sodium acetate, glucose, etc.), which results in high reagent consumption. On the other hand, the nitrification process requires continuous aeration to maintain an aerobic environment, resulting in high energy consumption. At the same time, a large amount of residual sludge is generated, further increasing the burden of sludge treatment. Summary of the Invention

[0003] The present application provides a combined denitrification process method and device, which solves the technical problems of the existing technology that the nitrification and denitrification processes require a large amount of external carbon source support, the treatment process has high energy consumption and a large amount of residual sludge production, and achieves the technical effect of reducing the amount of organic carbon source added, reducing the energy consumption of sewage denitrification and the amount of residual sludge.

[0004] In view of the above problems, on the one hand, the present application provides a combined denitrification process method, which includes: according to the sewage storage tank, the flocculent sludge of the sewage treatment plant is connected to the one-step PN / A reactor; through conditional constraints, the flocculent sludge in the one-step PN / A reactor is tamed into PN / A granular sludge; using the one-step PN / A reactor in which the sludge state is granular sludge to carry out a short-term nitrification reaction, and obtain PN / A reactor effluent; introducing the PN / A reactor effluent into the PD reactor, adding the organic carbon source from the carbon source box into the PD reactor for short-term denitrification, and obtaining PD reactor effluent; introducing the PD reactor effluent into the Anammox reactor, and deeply denitrifying the PD reactor effluent according to the Anammox reactor to obtain Anammox reactor effluent; discharging the Anammox reactor effluent according to the effluent storage tank.

[0005] Preferably, the flocculent sludge in the one-step PN / A reactor is tamed into PN / A granular sludge through conditional constraints, including: setting a mixed liquor sludge concentration constraint, the mixed liquor sludge concentration constraint is 2 to 4 g / L; setting a dissolved oxygen concentration constraint of the PN / A reactor, the dissolved oxygen concentration constraint is 0.2 to 0.5 mg / L; using the mixed liquor sludge concentration constraint and the dissolved oxygen concentration constraint as the conditional constraints, controlling the conversion of the flocculent sludge into granular sludge in the one-step PN / A reactor.

[0006] Preferably, the sludge volume index of the PN / A granular sludge is less than 50 mL / g.

[0007] Preferably, the effluent from the PN / A reactor is introduced into the PD reactor, and the organic carbon source is added from the carbon source box to the PD reactor for short-cut denitrification to obtain the effluent from the PD reactor, including: obtaining the characteristic concentration of the effluent from the PN / A reactor, wherein the characteristic concentration is NO 3- -N concentration; set the PD reactor inlet constraint, the PD reactor inlet constraint is COD / NO 3- -N value satisfies 2.5 to 3.0; taking the water inlet constraint of the PD reactor as the control target, the organic carbon source concentration of the organic carbon source box is adjusted according to the characteristic concentration.

[0008] Preferably, the water inlet to the Anammox reactor satisfies a predetermined mass concentration ratio constraint.

[0009] Preferably, the Anammox reactor includes an Anammox biofilm component, and the Anammox biofilm component is a non-woven fabric filler. The length of the non-woven fabric filler is 80 mm, and the height of the non-woven fabric filler is 150 mm.

[0010] Preferably, the one-step PN / A reactor is provided with a PN / A reaction zone and a PN / A precipitation zone.

[0011] Preferably, the PD reactor is provided with a PD reaction zone and a PD precipitation zone.

[0012] On the other hand, the present application also provides a combined denitrification process device, which includes: a sludge access module, which is used to connect the flocculent sludge of the sewage treatment plant to a one-step PN / A reactor according to a sewage storage tank; a sludge acclimation module, which is used to acclimate the flocculent sludge in the one-step PN / A reactor into PN / A granular sludge through conditional constraints; a first reaction module, which is used to use the one-step PN / A reactor in which the sludge state is granular sludge to carry out a short-term nitrification reaction and obtain PN / A reactor effluent; a second reaction module, which is used to introduce the PN / A reactor effluent into a PD reactor, and add the organic carbon source from the carbon source box into the PD reactor for short-term denitrification to obtain PD reactor effluent; a deep denitrification module, which is used to introduce the PD reactor effluent into an Anammox reactor, and perform deep denitrification on the PD reactor effluent according to the Anammox reactor to obtain Anammox reactor effluent; a drainage module, which is used to discharge the Anammox reactor effluent according to the effluent storage tank.

[0013] One or more technical solutions provided in this application have at least the following beneficial effects:

[0014] This application introduces flocculent sludge from sewage treatment plants into a one-step PN / A reactor, a PD reactor, and an Anammox reactor for treatment. Through the synergistic effects of short-range nitrification, short-range denitrification, and anaerobic ammonium oxidation, a combined denitrification pathway with low carbon source demand, low energy consumption, and low sludge production is constructed. By setting the mixed liquor sludge concentration constraint and dissolved oxygen concentration constraint of the PN / A reactor, the formation of PN / A granular sludge is effectively promoted, and the stability and denitrification efficiency of the reaction system are improved. Further, through characteristic concentration detection and COD / NO 3- -N ratio adjustment realizes precise dosing control of carbon source in PD reactor and significantly reduces the amount of external carbon source. At the same time, the Anammox reactor is equipped with predetermined concentration ratio control and non-woven fabric filler biofilm assembly to enhance the enrichment of Anammox bacteria and the continuity of reaction, ensuring that the effluent nitrogen concentration meets the standard. The overall solution also optimizes sludge separation and return flow by setting up sedimentation areas in different zones, ultimately achieving the technical effect of reducing the amount of organic carbon source added, reducing energy consumption and the amount of residual sludge, and improving denitrification efficiency and the stability of process system operation during the wastewater denitrification process.

[0015] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic flow chart of a combined denitrification process method provided in an embodiment of the present application.

[0017] Figure 2 This is a schematic diagram of component connections of a combined denitrification process method provided in an embodiment of the present application.

[0018] Figure 3 This is a morphology diagram of PN / A granular sludge in a combined denitrification process method provided in an embodiment of the present application.

[0019] Figure 4 This is a diagram of the denitrification efficiency of a combined denitrification process method provided in an embodiment of the present application in treating wastewater of different concentrations.

[0020] Figure 5 A schematic structural diagram of a combined denitrification process device provided in an embodiment of the present application.

[0021] Description of the accompanying drawings: sludge access module 10, sludge acclimation module 20, first reaction module 30, second reaction module 40, deep denitrification module 50, drainage module 60. DETAILED DESCRIPTION

[0022] The embodiments of the present application achieve the technical effect of reducing the amount of organic carbon source added, reducing the energy consumption of sewage denitrification and the amount of residual sludge by providing a solution to the technical problem that the nitrification and denitrification processes in the prior art require a large amount of external carbon source support, the treatment process has high energy consumption and a large amount of residual sludge.

[0023] Example 1, as Figure 1 As shown, the embodiment of the present application provides a combined denitrification process method, the method comprising:

[0024] Step S1: According to the sewage storage tank, the flocculent sludge of the sewage treatment plant is connected to the one-step PN / A reactor.

[0025] Specifically, flocculent sludge is a flocculent material composed of bacteria and organic particles, serving as the primary microbial carrier in wastewater biological treatment. The PN / A (Partial Nitrification-Anammox) process in a one-step PN / A reactor refers to a short-range nitrification-anaerobic ammonium oxidation process, integrating both the partial nitrification and anammox processes.

[0026] Flocculent sludge from the pretreated effluent of the sewage treatment plant is introduced into a one-step PN / A reactor via a wastewater storage tank. The reactor can adopt an SBR (Sequencing Batch Reactor) or a continuous flow CSTR (Completely Mixed Reactor) structure. In practice, sludge transfer can be achieved through an online level control system for the wastewater storage tank and an automatic transfer pump. For example, a PLC control system can be used to link the sludge pump to precisely control the hourly volume of sludge injected from the storage tank to ensure a stable bacterial load in the reactor.

[0027] Step S1 effectively introduces the microbial flocs in the activated sludge system into the PN / A system, providing a bacterial source and organic matter basis for subsequent granular sludge formation and reaction initiation. At the same time, the water inlet is adjusted through the reserve tank to ensure stable operation of the system.

[0028] Step S2: through conditional constraints, the flocculent sludge in the one-step PN / A reactor is acclimated into PN / A granular sludge.

[0029] Specifically, the conditional constraints include mixed liquor sludge concentration constraints and dissolved oxygen concentration constraints. In the one-step PN / A reactor, the reaction conditions such as the mixed liquor sludge concentration and dissolved oxygen concentration are controlled so that the sludge can continuously circulate in the reaction zone of the PN / A reactor, promote the aggregation and growth of microorganisms, and gradually domesticate the flocculent sludge into integrated PN / A granular sludge.

[0030] Furthermore, step S2 includes:

[0031] Step S21: setting a mixed liquor sludge concentration constraint, wherein the mixed liquor sludge concentration constraint is 2 to 4 g / L.

[0032] Step S22: setting a dissolved oxygen concentration constraint for the PN / A reactor, wherein the dissolved oxygen concentration constraint is 0.2 to 0.5 mg / L.

[0033] Step S23: controlling the conversion of the flocculent sludge into granular sludge in the one-step PN / A reactor using the mixed liquor sludge concentration constraint and the dissolved oxygen concentration constraint as the conditional constraints.

[0034] Specifically, in a one-step PN / A reactor, an online MLSS monitor, combined with a sludge return control system, automatically adjusts the sludge concentration in the reactor, maintaining a mixed liquor sludge concentration of 2 to 4 g / L during the reaction. Excessive sludge concentration can lead to restricted oxygen transfer, while low concentrations can lead to insufficient reaction rates. Alternatively, regular sludge removal and sludge age (SRT) adjustments can be used to control concentration.

[0035] The aeration system controls the dissolved oxygen concentration between 0.2 and 0.5 mg / L, effectively inhibiting the activity of ammonia-nitrogen oxidizing bacteria and promoting short-range nitrification. The aeration system uses an online dissolved oxygen sensor to monitor the dissolved oxygen concentration in real time and adjusts the oxygen supply rate in conjunction with a variable frequency blower aeration unit or microporous aerator system.

[0036] Combining the aforementioned sludge concentration and dissolved oxygen control mechanisms, a systematic control logic is formed. When the mixed liquor sludge concentration deviates from the target value, it is adjusted by automatically draining the sludge or reducing the sludge return ratio. When the dissolved oxygen concentration deviates from the target value, the oxygen supply is regulated by reducing the air volume or switching to a low-intensity aeration section. The entire control logic can be automated through the PLC and SCADA systems. By comprehensively controlling the sludge concentration and dissolved oxygen concentration, the transformation of flocculent sludge into granular sludge is promoted, gradually forming an integrated PN / A granular sludge.

[0037] Furthermore, the sludge volume index of the PN / A granular sludge is less than 50 mL / g.

[0038] Specifically, in the actual operation of the PN / A process, in order to obtain an efficient and stable denitrification system, it is necessary to select PN / A granular sludge with good settling performance. To this end, it is necessary to screen out PN / A granular sludge with a sludge volume index of less than 50mL / g. In the specific implementation process, a selective sedimentation separator (such as a precipitator or a hydraulic classification column) can be used to retain particles with faster settling speeds in the reactor and discharge flocculent sludge with poor floating properties. It is also possible to extend the sludge age (SRT) and control the shear strength to promote sludge granulation. Finally, the SVI measurement tool is used to determine whether the granular sludge meets the standards.

[0039] Step S2 achieves the rapid enrichment of PN / A granular sludge, providing an ideal reaction substrate and microbial basis for subsequent PD and Anammox reactions.

[0040] Step S3: using a one-step PN / A reactor in which the sludge is in the form of granular sludge to carry out a short-cut nitrification reaction and obtain PN / A reactor effluent.

[0041] Specifically, through the conditional constraints of step S2, the sludge state in the one-step PN / A reactor has been transformed from flocculent sludge to granular sludge. At this time, the microorganisms in the sludge perform a short-range nitrification reaction on the sewage, converting NH 4+ -N (ammonium nitrogen) is converted to NO 2- -N (nitrite nitrogen), the mixed liquid after the reaction is the effluent of the PN / A reactor.

[0042] Step S4: introducing the effluent from the PN / A reactor into the PD reactor, adding the organic carbon source from the carbon source box into the PD reactor for short-range denitrification, and obtaining the effluent from the PD reactor.

[0043] Specifically, the effluent from the PN / A reactor is transported to the PD reactor through a pipeline, and an organic carbon source is added from the organic carbon source box in a certain proportion. In the PD reactor, microorganisms use the organic carbon source to convert NO in the effluent from the PN / A reactor into 2--N (nitrite nitrogen) undergoes a short-range denitrification reaction to generate nitrogen and other products. The mixed liquid after the reaction is the effluent of the PD reactor.

[0044] Furthermore, step S4 includes:

[0045] Step S41: Obtain the characteristic concentration of the effluent from the PN / A reactor, which is NO 3- -N concentration.

[0046] Step S42: Set the PD reactor water inlet constraint, the PD reactor water inlet constraint is COD / NO 3- -N value satisfies 2.5 to 3.0.

[0047] Step S43: taking the water inlet constraint of the PD reactor as a control target, adjusting the organic carbon source concentration of the organic carbon source box according to the characteristic concentration.

[0048] Specifically, the PN / A reactor produces NO 2- -N is the main component, but there may still be some NH 4+ -N is directly oxidized to NO 3- -N, so before entering the PD reactor, it is necessary to monitor the NO in the PN / A effluent in real time. 3- -N concentration. You can use online ion selective electrode sensor, UV spectrum NO 3- -N analyzer, etc., to achieve NO 3- -N concentration continuous monitoring and feedback.

[0049] Set water inlet constraints, that is, dynamically control the addition of carbon source to make the COD / NO in the mixed liquid entering the PD reactor 3- The -N value should be between 2.5 and 3.0 to ensure that there is sufficient organic carbon source for the short-range denitrification reaction in the PD reactor, while avoiding waste and secondary pollution caused by excessive addition of organic carbon source, thereby improving the efficiency and economy of the denitrification reaction.

[0050] The monitored NO 3- -N concentration is input into the carbon source storage tank and the carbon source inlet pump carbon source control module, combined with the set COD / NO 3- -N target ratio, automatically adjust the carbon source addition concentration or flow rate. For example: using sodium acetate as the carbon source, equipped with a peristaltic pump, the PLC controller will adjust the carbon source concentration or flow rate according to the NO 3- -N concentration feedback signal is used to calculate and adjust the pump flow rate in real time, thereby stabilizing the PD reactor effluent quality.

[0051] Under the premise of maintaining a relatively low carbon source dosage, step S4 achieves efficient removal of nitrite and optimized utilization of carbon sources in the denitrification process, thereby reducing organic carbon source consumption and potential greenhouse gas emissions.

[0052] Step S5: introducing the PD reactor effluent into an Anammox reactor, performing deep denitrification on the PD reactor effluent according to the Anammox reactor to obtain Anammox reactor effluent.

[0053] Specifically, the Anammox reactor is used to achieve anaerobic ammonium oxidation, and its core microorganism is Anammox bacteria, which can convert NH 4+ -N (ammonium nitrogen) and NO 2- -N (nitrite nitrogen) is directly converted into nitrogen gas.

[0054] The effluent from the PD reactor is introduced into the Anammox reactor through a pipeline. In the Anammox reactor, anaerobic ammonium oxidizing bacteria utilize ammonia nitrogen and nitrite in the effluent from the PD reactor to carry out anaerobic ammonium oxidation reaction under anaerobic conditions, converting NH 4+ -N (ammonium nitrogen) and NO 2- -N (nitrite nitrogen) is converted into nitrogen gas, and the mixed liquid after the reaction is the effluent of the Anammox reactor.

[0055] Furthermore, the influent to the Anammox reactor satisfies a predetermined mass concentration ratio constraint.

[0056] Specifically, after conditioning in the PD reactor, the remaining NH 4+ -N and NO 2- -N must meet the requirements of the Anammox reaction, NO 2- -N and NH 4+ The mass concentration ratio of -N is 1 to 1.3, otherwise it will lead to incomplete reaction or bacterial inhibition. The degree of denitrification in the PD reactor can be adjusted by online ammonia nitrogen / nitrite detector, proportional flow control system, and feedback control of the front reactor to prevent NO 2- -N is excessively reduced by the carbon source. For example: if the actual NO 2- If the -N concentration is too high, the carbon source will be reduced through the control module of the carbon source storage tank and the carbon source inlet pump to reduce NO 3- -N to NO 2- -N conversion, restoring balance.

[0057] Step S5 achieves further efficient removal of ammonia nitrogen and nitrite under anaerobic conditions, significantly reducing the total nitrogen concentration without the need for additional carbon sources and aeration, resulting in significant overall energy savings and consumption reductions.

[0058] Step S6: discharging the effluent from the Anammox reactor into the effluent storage tank.

[0059] Specifically, the effluent from the Anammox reactor is piped to a effluent storage tank, from which it is then discharged based on actual needs (e.g., discharge standards, reuse requirements, etc.). The effluent storage tank can be equipped with a level control valve and flow meter to control the effluent.

[0060] Step S6 achieves buffering regulation and stable discharge of the treated water that meets the standards, improving the flexibility of the overall operation of the process system and the safety of the effluent water quality.

[0061] Furthermore, the Anammox reactor includes an Anammox biofilm component, and the Anammox biofilm component is a non-woven fabric filler. The length of the non-woven fabric filler is 80 mm, and the height of the non-woven fabric filler is 150 mm.

[0062] Specifically, the Anammox biofilm module is designed to facilitate the attachment, proliferation, and long-term survival of Anammox bacteria, preventing bacterial loss and increasing treatment load and reaction rate. Its dimensions of 80mm in length and 150mm in height provide ample surface area to accommodate a larger number of anammox microorganisms, thereby increasing reaction rates.

[0063] Furthermore, the one-step PN / A reactor is provided with a PN / A reaction zone and a PN / A precipitation zone.

[0064] Specifically, the PN / A reaction zone is the area in the one-step PN / A reactor where short-term nitrification and anaerobic ammonium oxidation reactions take place. In this area, microorganisms utilize ammonia nitrogen and other substances in the sewage to carry out short-term nitrification under specific environmental conditions, converting NH 4+ -N is partially oxidized to NO 2- -N, while carrying out anaerobic ammonium oxidation reaction to achieve nitrogen removal.

[0065] The PN / A sedimentation zone is the sedimentation area within the one-step PN / A reactor. Its primary function is to settle the sludge in the post-reaction mixed liquor. Because the PN / A granular sludge formed after the microbial reaction in the PN / A reaction zone has excellent settling properties, the sludge can effectively settle to the bottom of the reactor in the PN / A sedimentation zone, achieving mud-water separation and allowing the supernatant (PN / A reactor effluent) to enter the next treatment stage.

[0066] Furthermore, the PD reactor is provided with a PD reaction zone and a PD precipitation zone.

[0067] Specifically, the PD reaction zone is the area in the PD reactor where the short-range denitrification reaction takes place. In this area, microorganisms use organic carbon sources to convert NO from the effluent of the PN / A reactor into 2- -N undergoes short-term denitrification and is reduced to nitrogen gas, achieving further nitrogen removal.

[0068] The PD sedimentation zone is the sedimentation zone in the PD reactor. The mixed liquid after the reaction in the PD reaction zone enters the PD sedimentation zone, and the sludge therein settles to the bottom of the reactor. The supernatant (PD reactor effluent) is discharged into the next treatment link, namely the Anammox reactor.

[0069] Figure 2 This is a schematic diagram of the component connections of a combined denitrification process provided in an embodiment of the present application. The components required for the combined denitrification process include a sewage storage tank, three water inlet pumps (water inlet pump 2, water inlet pump 10, water inlet pump 14), an aeration pump 3, an aeration plate 4, two agitators (agitator 5, agitator 11), a one-step PN / A reactor 6, three effluent storage tanks (effluent storage tank 7, effluent storage tank 13, effluent storage tank 17), a carbon source storage tank 8, a carbon source liquid inlet pump 9, a PD reactor 12, an Anammox reactor 15, and a reflux pump 16. The one-step PN / A reactor 6 is provided with a PN / A reaction zone 6.1 and a PN / A precipitation zone 6.2, the PD reactor 12 is provided with a PD reaction zone 12.1 and a PD precipitation zone 12.2, and the Anammox reactor 15 is provided with an Anammox biofilm assembly 15.1.

[0070] One-step PN / A reactor 6 is connected to wastewater storage tank 1 via inlet pump 2. Its outlet is connected to outlet storage tank 7 and to PD reactor 12 via inlet pump 10. Carbon source storage tank 8 is connected to PD reactor 12 via carbon source inlet pump 9. The outlet of PD reactor 12 is connected to outlet storage tank 13 and to Anammox reactor 15 via inlet pump 14. The outlet of Anammox reactor 16 is connected to outlet storage tank 17.

[0071] In summary, the combined denitrification process provided in the embodiments of the present application has the following beneficial effects:

[0072] The embodiment of the present application introduces the flocculent sludge from the sewage treatment plant into a one-step PN / A reactor, a PD reactor and an Anammox reactor for treatment in sequence. Through the synergistic effect of short-range nitrification, short-range denitrification and anaerobic ammonium oxidation, a combined denitrification path with low carbon source demand, low energy consumption and low sludge production is constructed. By setting the mixed liquor sludge concentration constraint and dissolved oxygen concentration constraint of the PN / A reactor, the formation of PN / A granular sludge is effectively promoted, and the stability and denitrification efficiency of the reaction system are improved. Further, by characteristic concentration detection and COD / NO 3--N ratio adjustment realizes precise dosing control of carbon source in PD reactor and significantly reduces the amount of external carbon source. At the same time, the Anammox reactor is equipped with predetermined concentration ratio control and non-woven fabric filler biofilm assembly to enhance the enrichment of Anammox bacteria and the continuity of reaction, ensuring that the effluent nitrogen concentration meets the standard. The overall solution also optimizes sludge separation and return flow by setting up sedimentation areas in different zones, ultimately achieving the technical effect of reducing the amount of organic carbon source added, reducing energy consumption and the amount of residual sludge, and improving denitrification efficiency and the stability of process system operation during the wastewater denitrification process.

[0073] In Example 2, a combined denitrification process provided in this embodiment of the present application can be used for landfill leachate. Specifically, the total nitrogen concentration of the landfill leachate is 450 mg / L to 1280 mg / L, the organic carbon source in the carbon source storage tank is sodium acetate, and the effective volumes of the one-step PN / A reactor, PD reactor, and Anammox reactor are 7.5 L, 0.9 L, and 12.6 L, respectively. The execution process is as follows:

[0074] The one-step PN / A reactor was inoculated with activated sludge from an aerobic tank of a sewage treatment plant. The sludge concentration of the mixed liquor was 3.8 g / L. The dissolved oxygen concentration of the reactor was controlled below 0.5 mg / L. Short-range nitrification was started. The NO 2- -N accumulation rate is maintained above 95%, and NO 2- -N / NH 4+ After the -N value was controlled at 1.31 to 1.38, flocculent Anammox sludge was inoculated to culture the integrated PN / A granular sludge. After 39 days of operation, the PN / A granular sludge gradually formed (such as Figure 3 The one-step PN / A reactor, PD reactor and Anammox reactor were operated in series. The dissolved oxygen concentration of the one-step PN / A reactor was controlled at 0.2 mg / L to 0.3 mg / L, and the NH 4+ -N removal rate is controlled at 93% to 95%, and the COD / NO 3- -N is controlled at around 2.50, and the NO 2- -N accumulation rate is kept above 80%. The effluent of PD reactor enters Anammox reactor to complete deep denitrification, and the effluent of Anammox reactor is directly discharged.

[0075] like Figure 4 As shown in the figure, during the 211 days of combined process operation, the total nitrogen concentrations of the influent of the phase II, phase III and phase IV combined processes were 450 mg / L, 770 mg / L and 1280 mg / L, respectively. The one-step PN / A reactor of the combined process maintained a high denitrification activity, removing about 83% of the total nitrogen in the influent. The PD reactor only needed to add a small amount of organic carbon source to remove NO. 3--N is converted to NO 2- -N, and NH retained in the PN / A reactor 4+ -N enters the Anammox reactor to complete deep denitrification, NH 4+ -N and total nitrogen removal rates are greater than 99% and 98% respectively, and the effluent NH4+-N and TN concentrations are less than 0.6mg / L and 22mg / L respectively. Compared with traditional nitrification and denitrification processes, it saves approximately 60% of aeration energy consumption and 93% of organic carbon sources.

[0076] Example 3, as Figure 5 As shown, based on the same inventive concept as the above embodiment 1, this embodiment of the present application provides a combined denitrification process device, the device comprising:

[0077] The sludge access module 10 is used to access the flocculent sludge of the sewage treatment plant to the one-step PN / A reactor according to the sewage storage tank.

[0078] The sludge acclimation module 20 is used to acclimate the flocculent sludge in the one-step PN / A reactor into PN / A granular sludge through conditional constraints.

[0079] The first reaction module 30 is used to perform a short-cut nitrification reaction using a one-step PN / A reactor in which the sludge is in a granular sludge state, and obtain PN / A reactor effluent.

[0080] The second reaction module 40 is used to introduce the effluent of the PN / A reactor into the PD reactor, and add the organic carbon source from the carbon source box into the PD reactor for short-range denitrification to obtain the effluent of the PD reactor.

[0081] The deep denitrification module 50 is used to introduce the PD reactor effluent into the Anammox reactor, and perform deep denitrification on the PD reactor effluent according to the Anammox reactor to obtain Anammox reactor effluent.

[0082] The drainage module 60 is used to discharge the effluent of the Anammox reactor according to the effluent storage tank.

[0083] Furthermore, the first reaction module 30 in the embodiment of the present application is further configured to perform the following steps:

[0084] A mixed liquor sludge concentration constraint is set, and the mixed liquor sludge concentration constraint is 2 to 4 g / L; a dissolved oxygen concentration constraint is set for the PN / A reactor, and the dissolved oxygen concentration constraint is 0.2 to 0.5 mg / L; and the conversion of the flocculent sludge into granular sludge in the one-step PN / A reactor is controlled using the mixed liquor sludge concentration constraint and the dissolved oxygen concentration constraint as the conditional constraints.

[0085] Furthermore, the sludge volume index of the PN / A granular sludge is less than 50 mL / g.

[0086] Furthermore, the second reaction module 40 in the embodiment of the present application is further configured to perform the following steps:

[0087] The characteristic concentration of the effluent from the PN / A reactor is obtained, and the characteristic concentration is NO 3- -N concentration; set the PD reactor inlet constraint, the PD reactor inlet constraint is COD / NO 3- -N value satisfies 2.5 to 3.0; taking the water inlet constraint of the PD reactor as the control target, the organic carbon source concentration of the organic carbon source box is adjusted according to the characteristic concentration.

[0088] Furthermore, the influent to the Anammox reactor satisfies a predetermined mass concentration ratio constraint.

[0089] Furthermore, the Anammox reactor includes an Anammox biofilm component, and the Anammox biofilm component is a non-woven fabric filler. The length of the non-woven fabric filler is 80 mm, and the height of the non-woven fabric filler is 150 mm.

[0090] Furthermore, the one-step PN / A reactor is provided with a PN / A reaction zone and a PN / A precipitation zone.

[0091] Furthermore, the PD reactor is provided with a PD reaction zone and a PD precipitation zone.

[0092] Through the detailed description of a combined denitrification process method in the aforementioned embodiment 1, a person skilled in the art can clearly understand a combined denitrification process device in this embodiment. As for the device disclosed in embodiment 3, since it corresponds to the method disclosed in embodiment 1 and has corresponding functional modules and beneficial effects, the relevant parts can be referred to the method part description.

[0093] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A combined denitrification process, characterized in that: The method comprises: According to the sewage storage tank, the flocculent sludge from the sewage treatment plant is connected to the one-step PN / A reactor; Through conditional constraints, the flocculent sludge in the one-step PN / A reactor is domesticated into PN / A granular sludge; A one-step PN / A reactor in which the sludge state is granular sludge is used to carry out a short-cut nitrification reaction and obtain PN / A reactor effluent; The effluent from the PN / A reactor is introduced into the PD reactor, and the organic carbon source is added from the carbon source box to the PD reactor for short-range denitrification to obtain the effluent from the PD reactor; introducing the PD reactor effluent into an Anammox reactor, and performing deep denitrification on the PD reactor effluent according to the Anammox reactor to obtain Anammox reactor effluent; The effluent from the Anammox reactor is discharged from an effluent reserve tank.

2. A combined denitrification process according to claim 1, characterized in that: The flocculent sludge in the one-step PN / A reactor is tamed into PN / A granular sludge by conditional constraints, including: Setting a mixed liquor sludge concentration constraint, wherein the mixed liquor sludge concentration constraint is 2 to 4 g / L; Setting a dissolved oxygen concentration constraint for the PN / A reactor, wherein the dissolved oxygen concentration constraint is 0.2 to 0.5 mg / L; The mixed liquor sludge concentration constraint and the dissolved oxygen concentration constraint are used as the conditional constraints to control the conversion of the flocculent sludge into granular sludge in the one-step PN / A reactor.

3. A combined denitrification process according to claim 1, characterized in that: The sludge volume index of the PN / A granular sludge is less than 50 mL / g.

4. A combined denitrification process according to claim 1, characterized in that: The effluent from the PN / A reactor is introduced into the PD reactor, and an organic carbon source is added from a carbon source box to the PD reactor for short-range denitrification to obtain the effluent from the PD reactor, comprising: The characteristic concentration of the effluent from the PN / A reactor is obtained, and the characteristic concentration is NO 3- -N concentration; Set the PD reactor inlet constraint, which is COD / NO 3- -N value meets 2.5 to 3.0; Taking the water inlet constraint of the PD reactor as a control target, the organic carbon source concentration of the organic carbon source box is adjusted according to the characteristic concentration.

5. A combined denitrification process according to claim 1, characterized in that: The influent of the Anammox reactor meets the predetermined mass concentration ratio constraint.

6. A combined denitrification process according to claim 1, characterized in that: The Anammox reactor includes an Anammox biofilm component, which is a non-woven fabric filler. The length of the non-woven fabric filler is 80 mm, and the height of the non-woven fabric filler is 150 mm.

7. A combined denitrification process according to claim 1, characterized in that: The one-step PN / A reactor is provided with a PN / A reaction zone and a PN / A precipitation zone.

8. A combined denitrification process according to claim 1, characterized in that: The PD reactor is provided with a PD reaction zone and a PD precipitation zone.

9. A combined denitrification process device, characterized in that: The device is used to perform a combined denitrification process according to any one of claims 1 to 8, comprising: Sludge inlet module, used to connect the flocculent sludge from the sewage treatment plant to the one-step PN / A reactor according to the sewage storage tank; A sludge acclimation module, used for acclimating the flocculent sludge in the one-step PN / A reactor into PN / A granular sludge through conditional constraints; The first reaction module is used to perform a short-range nitrification reaction using a one-step PN / A reactor in which the sludge is in a granular sludge state, and obtain PN / A reactor effluent; The second reaction module is used to introduce the effluent of the PN / A reactor into the PD reactor, and add the organic carbon source from the carbon source box into the PD reactor for short-range denitrification to obtain the effluent of the PD reactor; A deep denitrification module is used to introduce the PD reactor effluent into an Anammox reactor, and perform deep denitrification on the PD reactor effluent according to the Anammox reactor to obtain Anammox reactor effluent; The drainage module is used to discharge the effluent of the Anammox reactor into the effluent storage tank.

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