A partial denitrification coupled anaerobic ammonium oxidation deep denitrification process

Abstract

A partial denitrification coupled anaerobic ammonium oxidation deep denitrification process promotes the enrichment, retention and synergistic symbiosis of AnAOB and DNB by adding gel particles with nitrogen adsorption function, biological affinity and the ability to fluidize in the reactor. At the same time, it creates a localized high substrate concentration microenvironment for them through nitrogen adsorption, reversing the starvation stress caused by low concentration and the disadvantages of unbalanced competition between AnAOB and DNB. Through process parameter optimization and process regulation, it ultimately achieves the retention, enrichment, activity enhancement and synergistic symbiosis of PD / A key functional bacteria, realizing low-carbon and high-load PD / A deep denitrification.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental protection, and in particular relates to a partial denitrification coupled anaerobic ammonia oxidation deep denitrification process. Background Art

[0002] To meet wastewater discharge standards, sewage treatment plants generally use denitrification as a deep denitrification process. This is an effective way to reduce TN concentrations in the secondary effluent of municipal wastewater treatment plants. However, this process requires the addition of large amounts of organic carbon sources to meet denitrification standards, increases sludge production, and ultimately increases wastewater treatment and operating costs by 10% to 20%. Furthermore, the denitrification process is prone to producing N2O, which has a strong greenhouse effect. Therefore, the development of low-carbon deep denitrification technologies is urgently needed.

[0003] The anaerobic ammonia oxidation process (Anammox, Anaerobic Ammonia Oxidation) discovered by Dutch scholars in the 1990s can convert NH4 + -N and NO 2- -N is converted into N2 for removal. Compared with traditional nitrification and denitrification, Anammox does not require aeration energy consumption, does not require carbon source addition, and can reduce N2O emissions and sludge production. + -N, but NO 2- -N often needs to be obtained by coupling with other nitrogen conversion pathways. According to the principle of microbial nitrogen conversion, partial denitrification coupled with anaerobic ammonium oxidation (PD / A) is expected to become an alternative solution for low-carbon denitrification of municipal sewage, that is, partial denitrification bacteria (PDB) convert NO 3- -N is converted to NO 2- -N, then, Anammox bacteria (AnAOB, Anaerobic Ammonia Oxidation Bacteria) use the NO2 generated by the PD process - -N and NH4 in sewage + -N reacts to produce N2; however, the current application of PD / A in deep denitrification still has the following technical difficulties:

[0004] The first is the enrichment and retention of AnAOB, the core functional bacteria in the PD / A process. AnAOB are autotrophic bacteria with long generation cycles, and low AnAOB abundance in sludge is one of the issues that limits the success of the Anammox coupling process. Therefore, how to enrich and retain AnAOB is one of the key issues in the implementation of the PD / A process.

[0005] Secondly, the synergistic metabolism and balance between the two functional bacteria in the PD / A coupling process under low nitrogen concentration conditions. The growth rate of AnAOB is much lower than that of DNB. Low nitrogen concentrations lead to a decrease in microbial reaction rate, making it difficult to maintain a balance between DNB and AnAOB, and reducing the denitrification volumetric efficiency. Balancing DNB and AnAOB to improve the reactor volumetric efficiency is also a major challenge facing the PD / A deep denitrification process.

[0006] Third, in the biological denitrification process, microorganisms secrete extracellular polymeric substances (EPS) to form aggregates such as biofilms or granular sludge to ensure the retention of denitrification functional bacteria and stable denitrification. However, in deep denitrification systems facing low substrate concentrations, microorganisms are susceptible to starvation stress. Not only is it difficult to synthesize new EPS, but existing EPS may also be consumed as energy, causing the aggregates to disintegrate or fall off, which in turn worsens the retention of AnAOB. Therefore, how to alleviate the starvation stress caused by low nitrogen concentrations is another challenge to ensure the efficient and stable operation of the PD / A deep denitrification system.

[0007] In view of the above technical difficulties, it is difficult for the existing PD / A process to achieve low concentrations of TN and NH4 + Deep denitrification under -N influent conditions cannot stably meet the more stringent (A or first-level) urban sewage treatment plant effluent discharge quality requirements in developed areas in the long term, that is, TN < 10 mg / L and NH4+-N < 1~5 mg / L. Summary of the Invention

[0008] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a partial denitrification coupled anaerobic ammonia oxidation deep denitrification process, which promotes the enrichment, retention and synergistic symbiosis of AnAOB and DNB by adding gel particles with nitrogen adsorption function, biological affinity and the ability to fluidize in the reactor. At the same time, through nitrogen adsorption, a local higher substrate concentration microenvironment is created for them, reversing the starvation stress caused by low concentration and the disadvantages of unbalanced competition between AnAOB and DNB. Through process parameter optimization and process regulation, the retention, enrichment, activity enhancement and synergistic symbiosis of PD / A key functional bacteria are finally achieved, realizing low-carbon and high-load PD / A deep denitrification.

[0009] To achieve the above objectives, the present invention adopts the following technical solutions:

[0010] A partial denitrification coupled anaerobic ammonium oxidation deep denitrification process comprises the following steps:

[0011] S1, using denitrification sludge and Anammox sludge as seed sludge, the inoculation ratio is (2-3): (3-5), the filling rate is 20%-30%; filling PVA / PA / ZL gel carrier, the filling rate is 20%-30%;

[0012] S2, NH4 + -N, NO 3- -N was used as substrate to start and operate the reactor, NaAc was used as carbon source, and the influent COD / TN was controlled at 2.5-4.0; NH4 + -N uses 7.5-20 mg·L -1 NH4Cl, NO3 - -N uses 7.5-20 mg·L -1 of NaNO3;

[0013] S3, collect inlet and outlet water samples more than 3 times a week, and use the national standard method to determine NH4 + -N, NO 2- -N, NO 3- -N concentration, the data of the stable period after startup are selected for calculation to evaluate the deep denitrification effect of the reactor;

[0014] S4. After the reactor is running stably, sludge samples are collected and the content of extracellular polysaccharide (PS) and extracellular protein (PN) is determined by anthrone-sulfuric acid spectrophotometry and the Lowry method. The sum of PN and PS is the concentration of extracellular polymeric substances (EPS). The abundance of functional bacteria in the sludge is analyzed by 16s rRNA sequencing using the Illumina Miseq sequencing platform to evaluate the enrichment of typical denitrifying bacteria Thauera and Pseudomonas, as well as the enrichment of anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia.

[0015] S5, after the reactor runs stably, collect sludge samples, test the partial denitrification activity and Anammox activity of the sludge through experiments, and use the nitrate reduction rate (r NO3 ) and nitrite production rate (r NO2 ) partial denitrification activity of the reaction sludge, using the ammonia nitrogen consumption rate (r NH4 ) reflects the Anammox activity to evaluate the synergistic metabolic denitrification effect of PDB and AnAOB.

[0016] The deep denitrification effect of the step S3 reactor:

[0017] Average effluent NH4 + -N concentration is 1.7 to 3.4 mg·L -1 ;

[0018] Average outlet NO2 --N concentration is 0.1~1.3mg·L -1 ;

[0019] Average outlet NO3 - -N concentration is 3.4 to 6.4 mg·L -1 ;

[0020] The TN concentration of the effluent is 6.0-9.5 mg·L -1 ;

[0021] Total nitrogen removal rate is 50.7-76.3%;

[0022] The average effluent meets the A (first level) standard of urban sewage treatment plant effluent quality in developed areas, that is, TN <10mg / L and NH4 + -N<1~5mg / L.

[0023] In step S4, the extracellular polysaccharide PS (Polysaccharide) and extracellular protein content PN (Protein), the sum of PN and PS is the extracellular polymer EPS (extracellular polymeric substances) concentration is:

[0024] PN concentration: 28.60~34.26mg·g-VSS -1 ;

[0025] PS concentration: 8.33~18.01mg·g-VSS -1 ;

[0026] EPS concentration: 36.71~48.65mg·g-VSS -1 ;

[0027] The enrichment effects of typical denitrifying bacteria Thauera and Pseudomonas, as well as the enrichment effects of anaerobic ammonia oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia are as follows:

[0028] Thauera abundance is: 2.17-2.25%;

[0029] The abundance of Pseudomonas is: 1.01-4.59%;

[0030] Candidatus_Brocadia abundance is: 2.36~3.19%;

[0031] Candidatus_Kuenenia abundance is: 0.54%~1.44%;

[0032] Microorganisms buffer the impact of hydraulic scouring on biofilms by secreting EPS. Typical denitrifying bacteria Thauera and Pseudomonas, as well as anaerobic ammonia oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia, all maintain a certain abundance ratio, indicating that the carrier is conducive to the synergistic symbiosis of functional microorganisms.

[0033] The nitrate reduction rate (r NO3 ), nitrite generation rate (r NO2 ), ammonia nitrogen consumption rate (r NH4 )for:

[0034] Nitrate reduction rate (r NO3 ) is 809.40~1506.58mg-N·g-VSS -1 ·d -1 ;

[0035] Nitrite production rate (r NO2 ) is 761.07~1170.41mg-N·g-VSS -1 ·d -1 ;

[0036] Ammonia nitrogen consumption rate (r NH4 ) is 333.37~538.43mg-N·g-VSS -1 ·d -1 ;

[0037] It can be seen that DNB and AnAOB in the carrier biofilm can respond to environmental shocks synchronously and have good buffering capacity, which has positive significance for the stable operation of the low-concentration PD / A process, that is, sufficient partial denitrification activity can continuously provide sufficient NO for the Anammox process. 2- -N, thereby enhancing the denitrification capacity of the system and maintaining the continuous and stable denitrification of PD / A.

[0038] The PVA / PA / ZL gel carrier in step S1 is a biological carrier with ammonia nitrogen adsorption and desorption function, which is a zeolite-loaded polyvinyl alcohol (PVA) and phytic acid (PV) co-crosslinked microbeads PVA / PA / ZL, with a zeolite loading of 2-6%, a microbead diameter of 3.0-5.0 mm, and a specific surface area of 13.8-19.0 m 2 ·g -1 , the sedimentation rate is 247.0~274.2m·h -1 ; The equilibrium adsorption capacity Q for ammonia nitrogen calculated using pseudo-second-order kinetics simulation e 0.64~0.94mg·g -1The maximum adsorption capacity Q for ammonia nitrogen calculated by Langmuir model is m 1.03~2.76mg·g -1 .

[0039] The reactor in step S2 adopts a UASB reactor system. The reactor is cylindrical with a height-to-diameter ratio of 10 to 15. The water flow path is bottom-in and top-out. An insulation jacket is provided on the outer layer of the reactor. The reactor temperature is controlled at 25 to 35°C by water bath circulation. The reactor is shaded to reduce the impact of light on microorganisms.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The present invention synthesizes a bio-carrier with ammonia nitrogen adsorption and desorption functions, so that it has both the ammonia nitrogen adsorption and desorption performance and the biological affinity for quickly forming a biofilm. The bio-carrier directional adsorption of ammonia nitrogen creates a competitive advantage for the attached and growing AnAOB, which is beneficial to the enrichment and retention of AnAOB, breaking through the limitation of insufficient biomass due to the slow growth of AnAOB and hydraulic scouring loss, which makes it difficult to achieve low-carbon denitrification.

[0042] (2) The present invention creates a good microhabitat for the synergistic symbiosis of AnAOB and PDB through the biological carrier with ammonia nitrogen adsorption and desorption function. In the deep denitrification system facing low substrate concentration, the biological carrier with ammonia nitrogen adsorption and desorption function can quickly adsorb ammonia nitrogen and create a higher substrate concentration domain in the gaps of the biological carrier, thereby alleviating the impact of low substrate concentration on PDB and AnAOB, and thus avoiding the problem of biofilm disintegration and shedding due to starvation stress, which is beneficial to the maintenance of the denitrification balance of DNB and AnAOB coupling, and provides a technical basis for the low-cost deep denitrification process suitable for low substrate concentration and low C / N urban sewage.

[0043] (3) The gel particle biocarrier synthesized in the present invention has good sedimentation performance and can be fluidized in an upflow UASB reactor, thereby avoiding the blockage obstacles existing in fixed-bed reactors and the additional energy consumption caused by the need for regular backwashing. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the process of an embodiment of the present invention.

[0045] Figure 2 Schematic diagram of the UASB reactor system of the embodiment of the present invention and the comparative example. DETAILED DESCRIPTION

[0046] The present invention is described in detail below with reference to the embodiments and accompanying drawings.

[0047] Example 1, with reference to Figure 1A partial denitrification coupled anaerobic ammonium oxidation deep denitrification process comprises the following steps:

[0048] S1, using denitrification sludge and Anammox sludge as seed sludge, with an inoculation ratio of 2:3 and a filling rate of 20%; filled with PVA / PA / ZL gel carrier, with a filling rate of 20%;

[0049] S2, NH4 + -N(NH4Cl, 20 mg·L -1 )、NO3 - -N(NaNO3,20mg·L -1 ) was used as substrate to start and operate the reactor, NaAc was used as carbon source, and the influent COD / TN was controlled at 2.5;

[0050] S3, collect inlet and outlet water samples three times a week and use the national standard method to determine NH4 + -N, NO 2- -N, NO 3- -N concentration, the data of the stable period after startup are selected for calculation to evaluate the deep denitrification effect of the reactor;

[0051] Average effluent NH4 + -N concentration was 3.4 mg·L -1 ;

[0052] Average outlet NO2 - -N concentration was 0.2 mg·L -1 ;

[0053] Average outlet NO3 - -N concentration was 6.4 mg·L -1 ;

[0054] The TN concentration of the effluent is 9.5 mg·L -1 ;

[0055] The total nitrogen removal rate was 76.3%;

[0056] The average effluent meets the A (first level) standard of urban sewage treatment plant effluent quality in developed areas, that is, TN <10mg / L and NH4 + -N<1~5mg / L;

[0057] S4. After the reactor operation stabilized, sludge samples were collected and the contents of extracellular polysaccharides (PS) and extracellular proteins (PN) were determined using anthrone-sulfuric acid spectrophotometry and the Lowry method. The sum of PN and PS was used to determine the concentration of extracellular polymeric substances (EPS). The abundance of functional bacteria in the sludge was analyzed using 16s rRNA sequencing on the Illumina Miseq sequencing platform to assess the enrichment of typical denitrifying bacteria Thauera and Pseudomonas, as well as the anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia.

[0058] PN concentration: 30.64 mg g-VSS -1 ;

[0059] PS concentration: 18.01 mg g-VSS -1 ;

[0060] EPS concentration: 48.65 mg g-VSS -1 ;

[0061] Thauera abundance is: 2.23%;

[0062] The abundance of Pseudomonas is: 2.58%;

[0063] Candidatus_Brocadia abundance is: 2.36%;

[0064] Candidatus_Kuenenia abundance is: 1.44%;

[0065] Microorganisms secrete EPS to buffer the impact of hydraulic scouring on the biofilm. Typical denitrifying bacteria Thauera and Pseudomonas, as well as anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia, all maintain a certain abundance ratio, indicating that the carrier is conducive to the symbiotic coexistence of functional microorganisms.

[0066] S5, after the reactor runs stably, collect sludge samples, test the partial denitrification activity and Anammox activity of the sludge through experiments, and use the nitrate reduction rate (r NO3 ) and nitrite production rate (r NO2 ) Partial denitrification activity of the reaction sludge was measured by using the ammonia nitrogen consumption rate (r NH4) reflects Anammox activity to evaluate the synergistic metabolic denitrification effect of PDB and AnAOB;

[0067] Nitrate reduction rate (r NO3 ) is 1085.54 mg-N·g-VSS -1 ·d -1 ;

[0068] Nitrite production rate (r NO2 ) is 891.71 mg-N·g-VSS -1 ·d -1 ;

[0069] Ammonia nitrogen consumption rate (r NH4 ) is 455.58 mg-N·g-VSS -1 ·d -1 ;

[0070] It can be seen that DNB and AnAOB in the carrier biofilm can respond to environmental shocks synchronously and have good buffering capacity, which has positive significance for the stable operation of the low-concentration PD / A process, that is, sufficient partial denitrification activity can continuously provide sufficient NO for the Anammox process. 2- -N, thereby enhancing the denitrification capacity of the system and maintaining the continuous and stable denitrification of PD / A.

[0071] The PVA / PA / ZL gel carrier in step S1 is a biological carrier with ammonia nitrogen adsorption and desorption function, which is a polyvinyl alcohol (PVA) and phytic acid (PV) co-crosslinked microbeads PVA / PA / ZL loaded with zeolite, with a zeolite loading of 2%, a microbead diameter of 3.0 mm, and a specific surface area of 18.8 m 2 ·g -1 , the sedimentation rate is 247.0m·h -1 ; The equilibrium adsorption capacity Q for ammonia nitrogen calculated using pseudo-second-order kinetics simulation e 0.64 mg·g -1 The maximum adsorption capacity Q for ammonia nitrogen calculated by Langmuir model is m 1.03 mg·g -1 .

[0072] The reactor in step S2 adopts UASB reactor system, as shown in the attached Figure 2 As shown, the reactor is cylindrical with a height-to-diameter ratio of 10, the water flow path is bottom-in and top-out, an insulation jacket is provided on the outer layer of the reactor, and the reactor temperature is controlled at 25°C by water bath circulation; the reactor is shaded to reduce the impact of light on microorganisms.

[0073] The technical parameters and effects of Example 1 are summarized in Table 1.

[0074] Example 2, reference Figure 1 A partial denitrification coupled anaerobic ammonium oxidation deep denitrification process comprises the following steps:

[0075] S1, using denitrification sludge and Anammox sludge as seed sludge, with an inoculation ratio of 3:4 and a filling rate of 25%; filled with PVA / PA / ZL gel carrier, with a filling rate of 25%;

[0076] S2, NH4 + -N(NH4Cl,12.5mg·L -1 )、NO3 - -N(NaNO3,12.5mg·L -1 ) was used as substrate to start and operate the reactor, NaAc was used as carbon source, and the influent COD / TN was controlled at 3.0;

[0077] S3, collect inlet and outlet water samples three times a week and use the national standard method to determine NH4 + -N, NO 2- -N, NO 3- -N concentration, the data of the stable period after startup are selected for calculation to evaluate the deep denitrification effect of the reactor;

[0078] Average effluent NH4 + -N concentration was 1.7 mg·L -1 ;

[0079] Average outlet NO2 - -N concentration is 0.1 mg·L -1 ;

[0080] Average outlet NO3 - -N concentration was 4.9 mg·L -1 ;

[0081] The TN concentration of the effluent is 6.5 mg·L -1 ;

[0082] The total nitrogen removal rate was 74.0%;

[0083] The average effluent meets the A (first level) standard of urban sewage treatment plant effluent quality in developed areas, that is, TN <10mg / L and NH4 + -N<1~5mg / L;

[0084] S4. After the reactor operation stabilized, sludge samples were collected and the contents of extracellular polysaccharides (PS) and extracellular proteins (PN) were determined using anthrone-sulfuric acid spectrophotometry and the Lowry method. The sum of PN and PS was used to determine the concentration of extracellular polymeric substances (EPS). The abundance of functional bacteria in the sludge was analyzed using 16s rRNA sequencing on the Illumina Miseq sequencing platform to assess the enrichment of typical denitrifying bacteria Thauera and Pseudomonas, as well as the anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia.

[0085] PN concentration: 29.38 mg g-VSS -1 ;

[0086] PS concentration: 9.61 mg g-VSS -1 ;

[0087] EPS concentration: 38.99 mg g-VSS -1 ;

[0088] Thauera abundance is: 2.25%;

[0089] The abundance of Pseudomonas is: 1.01%;

[0090] Candidatus_Brocadia abundance is: 2.60%;

[0091] Candidatus_Kuenenia abundance is: 1.35%;

[0092] Microorganisms secrete EPS to buffer the impact of hydraulic scouring on the biofilm. Typical denitrifying bacteria Thauera and Pseudomonas, as well as anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia, all maintain a certain abundance ratio, indicating that the carrier is conducive to the symbiotic coexistence of functional microorganisms.

[0093] S5, after the reactor runs stably, collect sludge samples, test the partial denitrification activity and Anammox activity of the sludge through experiments, and use the nitrate reduction rate (r NO3 ) and nitrite production rate (r NO2 ) Partial denitrification activity of the reaction sludge was measured by using the ammonia nitrogen consumption rate (r NH4) reflects Anammox activity to evaluate the synergistic metabolic denitrification effect of PDB and AnAOB;

[0094] Nitrate reduction rate (r NO3 ) is 981.36 mg-N·g-VSS -1 ·d -1 ;

[0095] Nitrite production rate (r NO2 ) is 910.73 mg-N·g-VSS -1 ·d -1 ;

[0096] Ammonia nitrogen consumption rate (r NH4 ) is 333.37 mg-N·g-VSS -1 ·d -1 ;

[0097] It can be seen that DNB and AnAOB in the carrier biofilm can respond to environmental shocks synchronously and have good buffering capacity, which has positive significance for the stable operation of the low-concentration PD / A process, that is, sufficient partial denitrification activity can continuously provide sufficient NO for the Anammox process. 2- -N, thereby enhancing the denitrification capacity of the system and maintaining the continuous and stable denitrification of PD / A.

[0098] The PVA / PA / ZL gel carrier in step S1 is a biological carrier with ammonia nitrogen adsorption and desorption function, which is a polyvinyl alcohol (PVA) and phytic acid (PV) co-crosslinked microbeads PVA / PA / ZL loaded with zeolite, with a zeolite loading of 4%, a microbead diameter of 4.0 mm, and a specific surface area of 19.0 m 2 ·g -1 , the sedimentation rate is 255.5m·h -1 ; The equilibrium adsorption capacity Q for ammonia nitrogen calculated using pseudo-second-order kinetics simulation e 0.87 mg·g -1 The maximum adsorption capacity Q for ammonia nitrogen calculated by Langmuir model is m 2.30 mg·g -1 .

[0099] The reactor in step S2 adopts UASB reactor system, as shown in the attached Figure 2 As shown, the reactor is cylindrical with a height-to-diameter ratio of 12.5. The water flow path is bottom-in and top-out. An insulation jacket is provided on the outer layer of the reactor, and the reactor temperature is controlled at 30°C by water bath circulation. The reactor is shaded to reduce the impact of light on microorganisms.

[0100] The technical parameters and effects of Example 2 are summarized in Table 1.

[0101] Example 3, reference Figure 1 A partial denitrification coupled anaerobic ammonium oxidation deep denitrification process comprises the following steps:

[0102] S1, using denitrification sludge and Anammox sludge as seed sludge, with an inoculation ratio of 3:5 and a filling rate of 30%; filled with PVA / PA / ZL gel carrier, with a filling rate of 30%;

[0103] S2, NH4 + -N(NH4Cl, 10 mg·L -1 )、NO3 - -N(NaNO3,10mg·L -1 ) was used as substrate to start and operate the reactor, NaAc was used as carbon source, and the influent COD / TN was controlled at 3.0;

[0104] S3, collect inlet and outlet water samples three times a week and use the national standard method to determine NH4 + -N, NO 2- -N, NO 3- -N concentration, the data of the stable period after startup are selected for calculation to evaluate the deep denitrification effect of the reactor;

[0105] Average effluent NH4 + -N concentration was 2.0 mg·L -1 ;

[0106] Average outlet NO2 - -N concentration is 0.1 mg·L -1 ;

[0107] Average outlet NO3 - -N concentration was 4.0 mg·L -1 ;

[0108] The TN concentration of the effluent is 6.0 mg·L -1 ;

[0109] The total nitrogen removal rate was 70.0%;

[0110] The average effluent meets the A (first level) standard of urban sewage treatment plant effluent quality in developed areas, that is, TN <10mg / L and NH4 + -N<1~5mg / L;

[0111] S4. After the reactor operation stabilized, sludge samples were collected and the contents of extracellular polysaccharides (PS) and extracellular proteins (PN) were determined using anthrone-sulfuric acid spectrophotometry and the Lowry method. The sum of PN and PS was used to determine the concentration of extracellular polymeric substances (EPS). The abundance of functional bacteria in the sludge was analyzed using 16s rRNA sequencing on the Illumina Miseq sequencing platform to assess the enrichment of typical denitrifying bacteria Thauera and Pseudomonas, as well as the anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia.

[0112] PN concentration: 28.60 mg g-VSS -1 ;

[0113] PS concentration: 8.33 mg g-VSS -1 ;

[0114] EPS concentration: 36.71 mg g-VSS -1 ;

[0115] Thauera abundance is: 2.17%;

[0116] The abundance of Pseudomonas is: 4.59%;

[0117] Candidatus_Brocadia abundance is: 2.49%;

[0118] Candidatus_Kuenenia abundance is: 0.85%;

[0119] Microorganisms secrete EPS to buffer the impact of hydraulic scouring on the biofilm. Typical denitrifying bacteria Thauera and Pseudomonas, as well as anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia, all maintain a certain abundance ratio, indicating that the carrier is conducive to the symbiotic coexistence of functional microorganisms.

[0120] S5, after the reactor runs stably, collect sludge samples, test the partial denitrification activity and Anammox activity of the sludge through experiments, and use the nitrate reduction rate (r NO3 ) and nitrite production rate (r NO2 ) Partial denitrification activity of the reaction sludge was measured by using the ammonia nitrogen consumption rate (r NH4) reflects Anammox activity to evaluate the synergistic metabolic denitrification effect of PDB and AnAOB;

[0121] Nitrate reduction rate (r NO3 ) is 809.40 mg-N·g-VSS -1 ·d -1 ;

[0122] Nitrite production rate (r NO2 ) is 761.07 mg-N·g-VSS -1 ·d -1 ;

[0123] Ammonia nitrogen consumption rate (r NH4 ) is 366.72 mg-N·g-VSS -1 ·d -1 ;

[0124] It can be seen that DNB and AnAOB in the carrier biofilm can respond to environmental shocks synchronously and have good buffering capacity, which has positive significance for the stable operation of the low-concentration PD / A process, that is, sufficient partial denitrification activity can continuously provide sufficient NO for the Anammox process. 2- -N, thereby enhancing the denitrification capacity of the system and maintaining the continuous and stable denitrification of PD / A.

[0125] The PVA / PA / ZL gel carrier in step S1 is a biological carrier with ammonia nitrogen adsorption and desorption function, which is a polyvinyl alcohol (PVA) and phytic acid (PV) co-crosslinked microbeads PVA / PA / ZL loaded with zeolite, with a zeolite loading of 5%, a microbead diameter of 4.0 mm, and a specific surface area of 15.4 m 2 ·g -1 , the sedimentation rate is 261.7m·h -1 ; The equilibrium adsorption capacity Q for ammonia nitrogen calculated using pseudo-second-order kinetics simulation e 0.90 mg·g -1 The maximum adsorption capacity Q for ammonia nitrogen calculated by Langmuir model is m 2.53 mg·g -1 .

[0126] The reactor in step S2 adopts UASB reactor system, as shown in the attached Figure 2 As shown, the reactor is cylindrical with a height-to-diameter ratio of 13. The water flow path is bottom-in and top-out. An insulation jacket is provided on the outer layer of the reactor. The temperature of the reactor is controlled at 32°C by water bath circulation. The reactor is shaded to reduce the impact of light on microorganisms.

[0127] The technical parameters and effects of Example 3 are summarized in Table 1.

[0128] Example 4, with reference to Figure 1 A partial denitrification coupled anaerobic ammonium oxidation deep denitrification process comprises the following steps:

[0129] S1, using denitrification sludge and Anammox sludge as seed sludge, with an inoculation ratio of 2:4 and a filling rate of 25%; filled with PVA / PA / ZL gel carrier, with a filling rate of 25%;

[0130] S2, NH4 + -N(NH4Cl,7.5mg·L -1 )、NO3 - -N(NaNO3,7.5mg·L -1 ) was used as substrate to start and operate the reactor, NaAc was used as carbon source, and the influent COD / TN was controlled at 4.0;

[0131] S3, collect inlet and outlet water samples three times a week and use the national standard method to determine NH4 + -N, NO2 - -N, NO3 - -N concentration, the data of the stable period after startup are selected for calculation to evaluate the deep denitrification effect of the reactor;

[0132] Average effluent NH4 + -N concentration was 2.8 mg·L -1 ;

[0133] Average outlet NO2 - -N concentration was 1.3 mg·L -1 ;

[0134] Average outlet NO3 - -N concentration was 3.4 mg·L -1 ;

[0135] The TN concentration of the effluent was 7.4 mg·L -1 ;

[0136] The total nitrogen removal rate was 50.7%;

[0137] The average effluent meets the A (first level) standard of urban sewage treatment plant effluent quality in developed areas, that is, TN <10mg / L and NH4 + -N<1~5mg / L;

[0138] S4. After the reactor operation stabilized, sludge samples were collected and the contents of extracellular polysaccharides (PS) and extracellular proteins (PN) were determined using anthrone-sulfuric acid spectrophotometry and the Lowry method. The sum of PN and PS was used to determine the concentration of extracellular polymeric substances (EPS). The abundance of functional bacteria in the sludge was analyzed using 16s rRNA sequencing on the Illumina Miseq sequencing platform to assess the enrichment of typical denitrifying bacteria Thauera and Pseudomonas, as well as the anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia.

[0139] PN concentration: 34.26 mg g-VSS -1 ;

[0140] PS concentration: 14.37 mg g-VSS -1 ;

[0141] EPS concentration: 48.63 mg g-VSS -1 ;

[0142] Thauera abundance is: 2.19%;

[0143] The abundance of Pseudomonas is: 3.29%;

[0144] Candidatus_Brocadia abundance is: 3.19%;

[0145] Candidatus_Kuenenia abundance is: 0.54%;

[0146] Microorganisms secrete EPS to buffer the impact of hydraulic scouring on the biofilm. Typical denitrifying bacteria Thauera and Pseudomonas, as well as anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia, all maintain a certain abundance ratio, indicating that the carrier is conducive to the symbiotic coexistence of functional microorganisms.

[0147] S5, after the reactor runs stably, collect sludge samples, test the partial denitrification activity and Anammox activity of the sludge through experiments, and use the nitrate reduction rate (r NO3 ) and nitrite production rate (r NO2 ) Partial denitrification activity of the reaction sludge was measured by using the ammonia nitrogen consumption rate (r NH4) reflects Anammox activity to evaluate the synergistic metabolic denitrification effect of PDB and AnAOB;

[0148] Nitrate reduction rate (r NO3 ) is 1506.58 mg-N·g-VSS -1 ·d -1 ;

[0149] Nitrite production rate (r NO2 ) is 1170.41 mg-N·g-VSS -1 ·d -1 ;

[0150] Ammonia nitrogen consumption rate (r NH4 ) is 538.43 mg-N·g-VSS -1 ·d -1 ;

[0151] It can be seen that DNB and AnAOB in the carrier biofilm can respond to environmental shocks synchronously and have good buffering capacity, which has positive significance for the stable operation of the low-concentration PD / A process, that is, sufficient partial denitrification activity can continuously provide sufficient NO for the Anammox process. 2- -N, thereby enhancing the denitrification capacity of the system and maintaining the continuous and stable denitrification of PD / A.

[0152] The PVA / PA / ZL gel carrier in step S1 is a biological carrier with ammonia nitrogen adsorption and desorption function, which is a polyvinyl alcohol (PVA) and phytic acid (PV) co-crosslinked microbeads PVA / PA / ZL loaded with zeolite, with a zeolite loading of 6%, a microbead diameter of 5.0 mm, and a specific surface area of 13.8 m 2 ·g -1 , the sedimentation rate is 274.2m·h -1 ; The equilibrium adsorption capacity Q for ammonia nitrogen calculated using pseudo-second-order kinetics simulation e 0.94 mg·g -1 The maximum adsorption capacity Q for ammonia nitrogen calculated by Langmuir model is m 2.76 mg·g -1 .

[0153] The reactor in step S2 adopts UASB reactor system, as shown in the attached Figure 2 As shown, the reactor is cylindrical with a height-to-diameter ratio of 15. The water flow path is bottom-in and top-out. An insulation jacket is provided on the outer layer of the reactor. The temperature of the reactor is controlled at 35°C by water bath circulation. The reactor is shaded to reduce the impact of light on microorganisms.

[0154] The technical parameters and effects of Example 4 are summarized in Table 1.

[0155] Comparative Example 1: A partial denitrification coupled anaerobic ammonium oxidation denitrification process based on a PVA / PA gel carrier, comprising the following steps:

[0156] S1, using denitrification sludge and Anammox sludge as seed sludge, with an inoculation ratio of 2:3 and a filling rate of 20%; filled with PVA / PA gel carrier, with a filling rate of 20%;

[0157] S2, NH4 + -N(NH4Cl, 20 mg·L -1 )、NO3 - -N(NaNO3,20mg·L -1 ) was used as substrate to start and operate the reactor, NaAc was used as carbon source, and the influent COD / TN was controlled at 2.5;

[0158] S3, collect inlet and outlet water samples three times a week and use the national standard method to determine NH4 + -N, NO 2- -N, NO 3- -N concentration, the data of the stable period after startup are selected for calculation to evaluate the deep denitrification effect of the reactor;

[0159] Average effluent NH4 + -N concentration was 5.5 mg·L -1 ;

[0160] Average outlet NO2 - -N concentration was 1.4 mg·L -1 ;

[0161] Average outlet NO3 - -N concentration was 9.2 mg·L -1 ;

[0162] The average effluent TN concentration was 15.8 mg·L -1 ;

[0163] The total nitrogen removal rate was 60.5%;

[0164] The average effluent exceeds the A (first level) standard for urban sewage treatment plant effluent quality in developed areas, that is, TN <10mg / L and NH4 + -N<1~5mg / L;

[0165] S4. After the reactor operation stabilized, sludge samples were collected and the contents of extracellular polysaccharides (PS) and extracellular proteins (PN) were determined using anthrone-sulfuric acid spectrophotometry and the Lowry method. The sum of PN and PS was used to determine the concentration of extracellular polymeric substances (EPS). The abundance of functional bacteria in the sludge was analyzed using 16s rRNA sequencing on the Illumina Miseq sequencing platform to assess the enrichment of typical denitrifying bacteria Thauera and Pseudomonas, as well as the anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia.

[0166] PN concentration: 23.38 mg g-VSS -1 ;

[0167] PS concentration: 14.51 mg g-VSS -1 ;

[0168] EPS concentration: 37.89 mg g-VSS -1 ;

[0169] Thauera abundance is: 0.16%;

[0170] The abundance of Pseudomonas is: 0.17%;

[0171] Candidatus_Brocadia abundance is: 1.91%;

[0172] Candidatus_Kuenenia abundance is: 1.06%;

[0173] The EPS secretion by microorganisms was less than that in Example 1 under the same influent and operating conditions; the abundance of typical denitrifying bacteria Thauera and Pseudomonas, as well as anaerobic ammonia oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia were also lower than those in Example 1 under the same influent and operating conditions;

[0174] S5, after the reactor runs stably, collect sludge samples, test the partial denitrification activity and Anammox activity of the sludge through experiments, and use the nitrate reduction rate (r NO3 ) and nitrite production rate (r NO2 ) Partial denitrification activity of the reaction sludge was measured by using the ammonia nitrogen consumption rate (r NH4 ) reflects Anammox activity to evaluate the synergistic metabolic denitrification effect of PDB and AnAOB;

[0175] Nitrate reduction rate (r NO3 ) is 607.90 mg-N·g-VSS -1 ·d -1 ;

[0176] Nitrite production rate (r NO2 ) is 503.78 mg-N·g-VSS -1 ·d -1 ;

[0177] Ammonia nitrogen consumption rate (r NH4 ) is 348.02 mg-N·g-VSS -1 ·d -1 ;

[0178] It can be seen that the activities of DNB and AnAOB in the carrier biofilm are lower than those in Example 1 under the same influent and operating conditions.

[0179] The biological carrier without ammonia nitrogen adsorption and desorption function in step S1 is polyvinyl alcohol (PVA) and phytic acid (PV) co-crosslinked microbeads PVA / PA, with a microbead diameter of 3.0 mm and a specific surface area of 35.9 m 2 ·g -1 , the sedimentation rate is 233.6m·h -1 The equilibrium adsorption capacity of ammonia nitrogen (Q e ) is 0.06 mg·g -1 The maximum adsorption capacity of ammonia nitrogen (Q m ) is 0.09 mg·g -1 ; Compared with the above embodiment, it basically does not have the nitrogen adsorption performance.

[0180] The reactor in step S2 adopts UASB reactor system, as shown in the attached Figure 2 As shown, the reactor is cylindrical with a height-to-diameter ratio of 10, the water flow path is bottom-in and top-out, an insulation jacket is provided on the outer layer of the reactor, and the reactor temperature is controlled at 25°C by water bath circulation; the reactor is shaded to reduce the impact of light on microorganisms.

[0181] The technical parameters and effects of Comparative Example 1 are summarized in Table 1.

[0182] Comparative Example 2, a partial denitrification coupled anaerobic ammonium oxidation denitrification process based on a PVA / PA gel carrier, comprising the following steps:

[0183] S1, using denitrification sludge and Anammox sludge as seed sludge, with an inoculation ratio of 3:4 and a filling rate of 25%; filled with PVA / PA gel carrier, with a filling rate of 25%;

[0184] S2, NH4 + -N(NH4Cl,12.5mg·L -1 )、NO3 - -N(NaNO3,12.5mg·L -1 ) was used as substrate to start and operate the reactor, NaAc was used as carbon source, and the influent COD / TN was controlled at 3.0;

[0185] S3, collect inlet and outlet water samples three times a week and use the national standard method to determine NH4 + -N, NO 2- -N, NO 3- -N concentration, the data of the stable period after startup are selected for calculation to evaluate the deep denitrification effect of the reactor;

[0186] Average effluent NH4 + -N concentration was 3.9 mg·L -1 ;

[0187] Average outlet NO2 - -N concentration is 0.1 mg·L -1 ;

[0188] Average outlet NO3 - -N concentration was 7.5 mg·L -1 ;

[0189] The average TN concentration of the effluent was 12.2 mg·L -1 ;

[0190] The total nitrogen removal rate was 51.2%;

[0191] The average effluent exceeds the A (first level) standard for urban sewage treatment plant effluent quality in developed areas, that is, TN <10mg / L and NH4 + -N<1~5mg / L;

[0192] S4. After the reactor operation stabilized, sludge samples were collected and the contents of extracellular polysaccharides (PS) and extracellular proteins (PN) were determined using anthrone-sulfuric acid spectrophotometry and the Lowry method. The sum of PN and PS was used to determine the concentration of extracellular polymeric substances (EPS). The abundance of functional bacteria in the sludge was analyzed using 16s rRNA sequencing on the Illumina Miseq sequencing platform to assess the enrichment of typical denitrifying bacteria Thauera and Pseudomonas, as well as the anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia.

[0193] PN concentration: 19.6 mg g-VSS -1 ;

[0194] PS concentration: 11.45 mg g-VSS -1 ;

[0195] EPS concentration: 30.65 mg g-VSS -1 ;

[0196] Thauera abundance is: 0.16%;

[0197] The abundance of Pseudomonas is: 0.31%;

[0198] Candidatus_Brocadia abundance is: 1.85%;

[0199] Candidatus_Kuenenia abundance is: 1.09%;

[0200] The EPS secretion by microorganisms was less than that in Example 2 under the same influent and operating conditions. The abundance of typical denitrifying bacteria Thauera and Pseudomonas, as well as anaerobic ammonia oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia, was also lower than that in Example 2 under the same influent and operating conditions.

[0201] S5, after the reactor runs stably, collect sludge samples, test the partial denitrification activity and Anammox activity of the sludge through experiments, and use the nitrate reduction rate (r NO3 ) and nitrite production rate (r NO2 ) Partial denitrification activity of the reaction sludge was measured by using the ammonia nitrogen consumption rate (r NH4 ) reflects the Anammox activity to evaluate the synergistic metabolic denitrification effect of PDB and AnAOB.

[0202] Nitrate reduction rate (r NO3 ) is 760.23 mg-N·g-VSS -1 ·d -1 ;

[0203] Nitrite production rate (r NO2 ) is 610.71 mg-N·g-VSS -1 ·d -1 ;

[0204] Ammonia nitrogen consumption rate (r NH4 ) is 306.47 mg-N·g-VSS -1 ·d -1;

[0205] It can be seen that the activities of DNB and AnAOB in the carrier biofilm are lower than those in Example 2 under the same influent and operating conditions.

[0206] The biological carrier without ammonia nitrogen adsorption and desorption function in step S1 is polyvinyl alcohol (PVA) and phytic acid (PV) co-crosslinked microbeads PVA / PA, with a microbead diameter of 3.0 mm and a specific surface area of 35.9 m 2 ·g -1 , the sedimentation rate is 233.6m·h -1 The equilibrium adsorption capacity of ammonia nitrogen (Q e ) is 0.06 mg·g -1 The maximum adsorption capacity of ammonia nitrogen (Q m ) is 0.09 mg·g -1 ; Compared with the above embodiment, it basically does not have the nitrogen adsorption performance.

[0207] The reactor in step S2 adopts UASB reactor system, as shown in the attached Figure 2 As shown, the reactor is cylindrical with a height-to-diameter ratio of 12.5. The water flow path is bottom-in and top-out. An insulation jacket is provided on the outer layer of the reactor, and the reactor temperature is controlled at 30°C by water bath circulation. The reactor is shaded to reduce the impact of light on microorganisms.

[0208] The technical parameters and effects of Comparative Example 2 are summarized in Table 1.

[0209] Comparative Example 3, a partial denitrification coupled anaerobic ammonium oxidation denitrification process based on a PVA / PA gel carrier, comprising the following steps:

[0210] S1, using denitrification sludge and Anammox sludge as seed sludge, with an inoculation ratio of 3:5 and a filling rate of 30%; filled with PVA / PA gel carrier, with a filling rate of 30%;

[0211] S2, NH4 + -N(NH4Cl, 10 mg·L -1 )、NO3 - -N(NaNO3,10mg·L -1 ) was used as substrate to start and operate the reactor, NaAc was used as carbon source, and the influent COD / TN was controlled to be 3.0;

[0212] S3, collect inlet and outlet water samples three times a week and use the national standard method to determine NH4 + -N, NO 2- -N, NO 3--N concentration, the data of the stable period after startup are selected for calculation to evaluate the deep denitrification effect of the reactor;

[0213] Average effluent NH4 + -N concentration was 3.4 mg·L -1 ;

[0214] Average outlet NO2 - -N concentration was 0.2 mg·L -1 ;

[0215] Average outlet NO3 - -N concentration was 6.4 mg·L -1 ;

[0216] The average TN concentration of the effluent was 10.5 mg·L -1 ;

[0217] The total nitrogen removal rate was 47.5%;

[0218] The average effluent exceeds the A (first level) standard for urban sewage treatment plant effluent quality in developed areas, that is, TN <10mg / L and NH4 + -N<1~5mg / L.

[0219] S4. After the reactor operation stabilized, sludge samples were collected and the contents of extracellular polysaccharides (PS) and extracellular proteins (PN) were determined using anthrone-sulfuric acid spectrophotometry and the Lowry method. The sum of PN and PS was used to determine the concentration of extracellular polymeric substances (EPS). The abundance of functional bacteria in the sludge was analyzed using 16s rRNA sequencing on the Illumina Miseq sequencing platform to assess the enrichment of typical denitrifying bacteria Thauera and Pseudomonas, as well as the anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia.

[0220] PN concentration: 19.6 mg g-VSS -1 ;

[0221] PS concentration: 7.30 mg g-VSS -1 ;

[0222] EPS concentration: 36.90 mg g-VSS -1 ;

[0223] Thauera abundance is: 0.18%;

[0224] The abundance of Pseudomonas is: 0.52%;

[0225] Candidatus_Brocadia abundance is: 1.48%;

[0226] Candidatus_Kuenenia abundance is: 0.53%;

[0227] The EPS secretion of microorganisms was less than that of Example 3 under the same influent and operating conditions. The abundance of typical denitrifying bacteria Thauera and Pseudomonas, as well as anaerobic ammonia oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia were also lower than that of Example 3 under the same influent and operating conditions.

[0228] S5, after the reactor runs stably, collect sludge samples, test the partial denitrification activity and Anammox activity of the sludge through experiments, and use the nitrate reduction rate (r NO3 ) and nitrite production rate (r NO2 ) Partial denitrification activity of the reaction sludge was measured by using the ammonia nitrogen consumption rate (r NH4 ) reflects Anammox activity to evaluate the synergistic metabolic denitrification effect of PDB and AnAOB;

[0229] Nitrate reduction rate (r NO3 ) is 569.00 mg-N·g-VSS -1 ·d -1 ;

[0230] Nitrite production rate (r NO2 ) is 523.71 mg-N·g-VSS -1 ·d -1 ;

[0231] Ammonia nitrogen consumption rate (r NH4 ) is 275.98 mg-N·g-VSS -1 ·d -1 ;

[0232] It can be seen that the activities of DNB and AnAOB in the carrier biofilm are lower than those in Example 3 under the same influent and operating conditions.

[0233] The biological carrier without ammonia nitrogen adsorption and desorption function in step S1 is polyvinyl alcohol (PVA) and phytic acid (PV) co-crosslinked microbeads PVA / PA, with a microbead diameter of 3.0 mm and a specific surface area of 35.9 m 2 ·g -1 , the sedimentation rate is 233.6m·h -1 The equilibrium adsorption capacity of ammonia nitrogen (Qe ) is 0.06 mg·g -1 The maximum adsorption capacity of ammonia nitrogen (Q m ) is 0.09 mg·g -1 ; Compared with the above embodiment, it basically does not have the nitrogen adsorption performance.

[0234] The reactor in step S2 adopts UASB reactor system, as shown in the attached Figure 2 As shown, the reactor is cylindrical with a height-to-diameter ratio of 13. The water flow path is bottom-in and top-out. An insulation jacket is provided on the outer layer of the reactor. The temperature of the reactor is controlled at 32°C by water bath circulation. The reactor is shaded to reduce the impact of light on microorganisms.

[0235] The technical parameters and effects of Comparative Example 3 are summarized in Table 1.

[0236] Comparative Example 4, a partial denitrification coupled anaerobic ammonium oxidation denitrification process based on a PVA / PA gel carrier, comprising the following steps:

[0237] S1, using denitrification sludge and Anammox sludge as seed sludge, with an inoculation ratio of 2:4 and a filling rate of 25%; filled with PVA / PA gel carrier, with a filling rate of 25%;

[0238] S2, NH4 + -N(NH4Cl,7.5mg·L -1 )、NO3 - -N(NaNO3,7.5mg·L -1 ) was used as substrate to start and operate the reactor, NaAc was used as carbon source, and the influent COD / TN was controlled to be 4;

[0239] S3, collect inlet and outlet water samples three times a week, and use the national standard method to determine NH4 + -N, NO 2- -N, NO3 - -N concentration, the data of the stable period after startup are selected for calculation to evaluate the deep denitrification effect of the reactor;

[0240] Average effluent NH4 + -N concentration was 4.7 mg·L -1 ;

[0241] Average outlet NO2 - -N concentration was 0.5 mg·L -1 ;

[0242] Average outlet NO3 - -N concentration was 5.1 mg·L -1 ;

[0243] The average effluent TN concentration was 10.3 mg·L -1 ;

[0244] The total nitrogen removal rate was 31.3%;

[0245] The effluent exceeds the A (first level) standard for urban sewage treatment plants in developed areas, that is, TN < 10 mg / L and NH4 + -N<1~5mg / L;

[0246] S4. After the reactor operation stabilized, sludge samples were collected and the contents of extracellular polysaccharides (PS) and extracellular proteins (PN) were determined using anthrone-sulfuric acid spectrophotometry and the Lowry method. The sum of PN and PS was used to determine the concentration of extracellular polymeric substances (EPS). The abundance of functional bacteria in the sludge was analyzed using 16s rRNA sequencing on the Illumina Miseq sequencing platform to assess the enrichment of typical denitrifying bacteria Thauera and Pseudomonas, as well as the anaerobic ammonia-oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia.

[0247] PN concentration: 20.4 mg g-VSS -1 ;

[0248] PS concentration: 10.37 mg g-VSS -1 ;

[0249] EPS concentration: 30.77 mg g-VSS -1 ;

[0250] Thauera abundance is: 0.17%;

[0251] The abundance of Pseudomonas is: 0.49%;

[0252] Candidatus_Brocadia abundance is: 1.52%;

[0253] Candidatus_Kuenenia abundance is: 0.32%;

[0254] The EPS secreted by microorganisms was less than that in Example 4 under the same influent and operating conditions. The abundance of typical denitrifying bacteria Thauera and Pseudomonas, as well as anaerobic ammonia oxidizing bacteria Candidatus_Brocadia and Candidatus_Kuenenia, was also lower than that in Example 4 under the same influent and operating conditions.

[0255] S5, after the reactor runs stably, collect sludge samples, test the partial denitrification activity and Anammox activity of the sludge through experiments, and use the nitrate reduction rate (r NO3 ) and nitrite production rate (r NO2 ) Partial denitrification activity of the reaction sludge was measured by using the ammonia nitrogen consumption rate (r NH4 ) reflects Anammox activity to evaluate the synergistic metabolic denitrification effect of PDB and AnAOB;

[0256] Nitrate reduction rate (r NO3 ) is 732.13 mg-N·g-VSS -1 ·d -1 ;

[0257] Nitrite production rate (r NO2 ) is 608.4 mg-N·g-VSS -1 ·d -1 ;

[0258] Ammonia nitrogen consumption rate (r NH4 ) is 237.95 mg-N·g-VSS -1 ·d -1 ;

[0259] It can be seen that the activities of DNB and AnAOB in the carrier biofilm are lower than those in Example 4 under the same water inlet and operating conditions. The biological carrier without ammonia nitrogen adsorption and desorption function in step S1 is polyvinyl alcohol (PVA) and phytic acid (PV) co-crosslinked microbeads PVA / PA, with a microbead diameter of 3.0 mm and a specific surface area of 35.9 m 2 ·g -1 , the sedimentation rate is 233.6m·h -1 The equilibrium adsorption capacity of ammonia nitrogen (Q e ) is 0.06 mg·g -1 The maximum adsorption capacity of ammonia nitrogen (Q m ) is 0.09 mg·g -1 ; Compared with the above embodiment, it basically does not have the nitrogen adsorption performance.

[0260] The reactor in step S2 adopts UASB reactor system, as shown in the attached Figure 2 As shown, the reactor is cylindrical with a height-to-diameter ratio of 15. The water flow path is bottom-in and top-out. An insulation jacket is provided on the outer layer of the reactor. The temperature of the reactor is controlled at 35°C by water bath circulation. The reactor is shaded to reduce the impact of light on microorganisms.

[0261] The technical parameters and effects of Comparative Example 4 are summarized in Table 1.

[0262] Table 1 Summary of the PD / A deep denitrification effects of Examples 1-4 and Comparative Examples 1-4

[0263]

[0264]

Claims

1. A partial denitrification coupled anaerobic ammonium oxidation deep denitrification process, characterized in that: The following steps are involved: S1, using denitrification sludge and Anammox sludge as seed sludge, the inoculation ratio is (2-3): (3-5), and the filling rate is 20%-30%; filled with polyvinyl alcohol PVA / phytic acid PA / zeolite ZL gel carrier, the filling rate is 20%-30%; S2, NH4 + -N, NO3 - -N was used as substrate to start and operate the reactor, NaAc was used as carbon source, and the influent COD / TN was controlled at 2.5-4.0; NH4 + -N uses 7.5-20 mg·L -1 NH4Cl, NO3 - -N uses 7.5-20 mg·L -1 of NaNO3; S3, collect inlet and outlet water samples more than 3 times a week, and use the national standard method to determine NH4 + -N, NO2 - -N, NO3 - -N concentration, the data of the stable period after startup are selected for calculation to evaluate the deep denitrification effect of the reactor; S4. After the reactor runs stably, sludge samples are collected and the extracellular polysaccharide (PS) and extracellular protein (PN) content are determined using anthrone-sulfuric acid spectrophotometry and the Lowry method. The extracellular protein content (PN) concentration and the extracellular polysaccharide (PS) concentration are summed to obtain the extracellular polymer (EPS) concentration. The abundance of functional bacteria in the sludge is analyzed using 16s rRNA sequencing on the Illumina Miseq sequencing platform to evaluate the enrichment of typical denitrifying bacteria Thauera and Pseudomonas, as well as the anaerobic ammonia-oxidizing bacteria Candidatus Brocadia and Candidatus Kuenenia. S5, after the reactor runs stably, collect sludge samples, test the partial denitrification activity and Anammox activity of the sludge through experiments, and use the nitrate reduction rate r NO3 and nitrite production rate r NO2 The partial denitrification activity of the reaction sludge was calculated using the ammonia nitrogen consumption rate r NH4 Anammox activity was measured to evaluate the synergistic metabolic denitrification effect of PDB and AnAOB; The polyvinyl alcohol PVA / phytic acid PA / zeolite ZL gel carrier in step S1 is a biological carrier with ammonia nitrogen adsorption and desorption function, which is a polyvinyl alcohol PVA and phytic acid PA co-crosslinked microbeads polyvinyl alcohol PVA / phytic acid PA / zeolite ZL loaded with zeolite, with a zeolite loading of 2-6%, a microbead diameter of 3.0-5.0 mm, and a specific surface area of 13.8-19.0 m 2 ·g -1 , the sedimentation rate is 247.0~274.2m·h -1 ; The equilibrium adsorption capacity Q for ammonia nitrogen calculated using pseudo-second-order kinetics simulation e 0.64~0.94mg·g -1 The maximum adsorption capacity Q for ammonia nitrogen calculated by Langmuir model is m 1.03~2.76mg·g -1 .

2. The process according to claim 1, characterized in that The deep denitrification effect of the step S3 reactor: Average effluent NH4 + -N concentration is 1.7 to 3.4 mg·L -1 ; Average outlet NO2 - -N concentration is 0.1~1.3mg·L -1 ; Average outlet NO3 - -N concentration is 3.4 to 6.4 mg·L -1 ; The TN concentration of the effluent is 6.0-9.5 mg·L -1 ; The total nitrogen removal rate is 50.7-76.3%.

3. The process according to claim 1, characterized in that The concentration of extracellular polysaccharide PS and extracellular protein content PN in step S4 is the sum of the extracellular protein content PN and extracellular polysaccharide PS concentration to obtain the extracellular polymer EPS concentration: Extracellular protein content PN concentration: 28.60~34.26mg·g-VSS -1 ; The concentration of extracellular polysaccharide PS is 8.33~18.01mg·g-VSS -1 ; Extracellular polymer EPS concentration: 36.71~48.65mg·g-VSS -1 ; The enrichment effects of typical denitrifying bacteria Thauera and Pseudomonas, as well as the enrichment effects of anaerobic ammonia oxidizing bacteria Candidatus Brocadia and Candidatus Kuenenia are as follows: Thauera abundance is: 2.17-2.25%; The abundance of Pseudomonas is: 1.01-4.59%; The abundance of Candidatus Brocadia is: 2.36~3.19%; The abundance of Candidatus Kuenenia is: 0.54% to 1.44%; Microorganisms buffer the impact of hydraulic scouring on biofilms by secreting extracellular polymers (EPS). Typical denitrifying bacteria Thauera and Pseudomonas, as well as anaerobic ammonia oxidizing bacteria Candidatu Brocadia and Candidatus Kuenenia, all maintain their abundance ratios, indicating that the carrier is conducive to the synergistic symbiosis of functional microorganisms.

4. The process according to claim 1, characterized in that The nitrate reduction rate r in step S5 is NO3 , nitrite generation rate r NO2 , ammonia nitrogen consumption rate r NH4 for: Nitrate reduction rate r NO3 809.40~1506.58mg-N·g-VSS -1 ·d -1 ; Nitrite production rate r NO2 761.07~1170.41mg-N·g-VSS -1 ·d -1 ; Ammonia nitrogen consumption rate r NH4 333.37~538.43mg-N·g-VSS -1 ·d -1 .

5. The process according to claim 1, characterized in that The reactor in step S2 adopts a UASB reactor system. The reactor is cylindrical with a height-to-diameter ratio of 10 to 15. The water flow path is bottom-in and top-out. An insulation jacket is provided on the outer layer of the reactor. The reactor temperature is controlled at 25 to 35°C by water bath circulation. The reactor is shaded to reduce the impact of light on microorganisms.

6. The process according to claim 1, characterized in that The following steps are involved: S1, using denitrification sludge and Anammox sludge as seed sludge, with an inoculation ratio of 2:3 and a filling rate of 20%; filled with polyvinyl alcohol PVA / phytic acid PA / zeolite ZL gel carrier, with a filling rate of 20%; S2, NH4 + -N, NO3 - -N was used as substrate to start and operate the reactor, NaAc was used as carbon source, and the influent COD / TN was controlled at 2.5; NH4 + -N is 20mg·L -1 NH4Cl, NO3 - -N is 20mg·L -1 of NaNO3; S3, collect inlet and outlet water samples three times a week and use the national standard method to determine NH4 + -N, NO2 - -N, NO3 - -N concentration, the data of the stable period after startup are selected for calculation to evaluate the deep denitrification effect of the reactor; Average effluent NH4 + -N concentration was 3.4 mg·L -1 ; Average outlet NO2 - -N concentration was 0.2 mg·L -1 ; Average outlet NO3 - -N concentration was 6.4 mg·L -1 ; The TN concentration of the effluent is 9.5 mg·L -1 ; The total nitrogen removal rate was 76.3%; S4. After the reactor runs stably, sludge samples are collected and the extracellular polysaccharide (PS) and extracellular protein (PN) content are determined using anthrone-sulfuric acid spectrophotometry and the Lowry method. The extracellular protein content (PN) concentration and the extracellular polysaccharide (PS) concentration are summed to obtain the extracellular polymer (EPS) concentration. The abundance of functional bacteria in the sludge is analyzed using 16s rRNA sequencing on the Illumina Miseq sequencing platform to evaluate the enrichment of typical denitrifying bacteria Thauera and Pseudomonas, as well as the anaerobic ammonia-oxidizing bacteria Candidatus Brocadia and Candidatus Kuenenia. Extracellular protein content PN concentration is: 30.64 mg g-VSS -1 ; The concentration of extracellular polysaccharide PS is: 18.01 mg g-VSS -1 ; The concentration of extracellular polymer EPS is 48.65 mg g-VSS -1 ; Thauera abundance is: 2.23%; The abundance of Pseudomonas is: 2.58%; Candidatus Brocadia abundance is: 2.36%; Candidatus Kuenenia abundance is: 1.44%; Microorganisms secrete extracellular polymers (EPS) to buffer the impact of hydraulic scouring on the biofilm. Typical denitrifying bacteria, Thauera and Pseudomonas, as well as anaerobic ammonia-oxidizing bacteria, Candidatus Brocadia and Candidatus Kuenenia, all maintain their abundance, indicating that the carrier is conducive to the symbiotic coexistence of functional microorganisms. S5, after the reactor runs stably, collect sludge samples, test the partial denitrification activity and Anammox activity of the sludge through experiments, and use the nitrate reduction rate r NO3 and nitrite production rate r NO2 The partial denitrification activity of the reaction sludge was calculated using the ammonia nitrogen consumption rate r NH4 Anammox activity was measured to evaluate the synergistic metabolic denitrification effect of PDB and AnAOB; Nitrate reduction rate r NO3 1085.54 mg-N·g-VSS -1 ·d -1 ; Nitrite production rate r NO2 891.71 mg-N·g-VSS -1 ·d -1 ; Ammonia nitrogen consumption rate r NH4 455.58 mg-N·g-VSS -1 ·d -1 ; The DNB and AnAOB in the carrier biofilm can respond to environmental shocks synchronously and have good buffering capacity, that is, sufficient partial denitrification activity can continuously provide sufficient NO2 for the Anammox process. - -N, thereby enhancing the denitrification capacity of the system.

7. The process according to claim 6, characterized in that The polyvinyl alcohol PVA / phytic acid PA / zeolite ZL gel carrier in step S1 is a biological carrier with ammonia nitrogen adsorption and desorption function, which is a polyvinyl alcohol PVA and phytic acid PA co-crosslinked microbeads loaded with zeolite, polyvinyl alcohol PVA / phytic acid PA / zeolite ZL, with a zeolite loading of 2%, a microbead diameter of 3.0 mm, and a specific surface area of 18.8 m 2 ·g -1 , the sedimentation rate is 247.0m·h -1 ; The equilibrium adsorption capacity Q for ammonia nitrogen calculated using pseudo-second-order kinetics simulation e 0.64 mg·g -1 The maximum adsorption capacity Q for ammonia nitrogen calculated by Langmuir model is m 1.03 mg·g -1 .

8. The process according to claim 6, characterized in that The reactor in step S2 adopts a UASB reactor system. The reactor is cylindrical with a height-to-diameter ratio of 10, the water flow path is bottom-in and top-out, an insulation jacket is provided on the outer layer of the reactor, and the reactor temperature is controlled at 25°C by water bath circulation; the reactor is shaded to reduce the impact of light on microorganisms.

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