Method for treating biogas slurry by combining short-cut nitrification and denitrification with cell immobilized anaerobic ammonia oxidation

Abstract

The invention discloses a method for treating biogas slurry by combining short-cut nitrification and denitrification with cell immobilized anaerobic ammonia oxidation, which is realized on the basis of a reactor component and comprises the following steps: S1, inoculating short-cut nitrification and denitrification sludge; s2, nitrification and denitrification treatment: S2-1, pre-starting a short-cut nitrification and denitrification reaction tower; s2-2, carrying out continuous treatment; s3, inoculating the cell immobilized anaerobic ammonia oxidation sludge; s4, carrying out cell immobilization anaerobic ammonia oxidation treatment; s4-1, pre-starting the cell immobilized anaerobic ammonia oxidation reactor; and S4-2, carrying out continuous treatment. The method is applied to treatment of high-ammonia-nitrogen wastewater, compared with a traditional nitrification and denitrification method, the oxygen supply amount is reduced by 40-60%, the COD demand amount is reduced by 100%, the sludge yield is reduced by 60-90%, and compared with a common short-cut nitrification and denitrification-anaerobic ammonia oxidation technology, the method has the advantages that the treatment cost is reduced, and the treatment efficiency is improved. The NO2 <->-N / NH4 < + >-N ratio is stable and convenient to control, NOB can be effectively inhibited, the enrichment speed of AnAOB is accelerated, and the resistance to factors such as heavy metals and antibiotics is improved.

Description

Technical Field

[0001] The invention relates to the technical field of ammonia nitrogen wastewater treatment, and in particular to a method for treating biogas slurry by combining short-range nitrification and denitrification with cell-immobilized anaerobic ammonia oxidation. Background Art

[0002] In recent years, sewage treatment technology, especially the treatment of high ammonia nitrogen wastewater, has received much attention and research. Among the many sewage treatment technologies, the short-cut nitrification and denitrification combined with anaerobic ammonium oxidation technology is considered to be the most promising high ammonia nitrogen wastewater treatment technology because it has obvious advantages such as no need for external carbon source, saving aeration energy consumption and low sludge production.

[0003] Among them, the short-term nitrification and denitrification process is based on the difference in growth rate of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) under different environmental factors such as temperature, dissolved oxygen (dO) and pH, to achieve the specific inhibition and removal of NOB, and promote AOB to become the dominant bacteria, thereby controlling the traditional full-process nitrification at nitrite (NO2 - -N) stage, and directly with NO2 - -N acts as the final hydrogen acceptor for electrons in denitrification.

[0004] The anaerobic ammonium oxidation process is a process in which anaerobic ammonium oxidizing bacteria (AnAOB) use NO2 - -N as electron acceptor, ammonium (NH4 + -N) as an electron donor and directly converts both into nitrogen gas (N2) and part of nitrate (NO3 - -N), however, in practical applications, both often face problems such as NO2 - -N / NH4 + There are a series of challenges, such as the difficulty in stably controlling the -N ratio, the inhibition of NOB adaptation, the long growth cycle of AnAOB, slow enrichment, and extreme sensitivity to environmental factors such as heavy metals and antibiotics. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention provides a method for treating biogas slurry by combining short-range nitrification and denitrification with cell-immobilized anaerobic ammonia oxidation.

[0006] The technical solution of the present invention is:

[0007] A method for treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation, wherein the biogas slurry is diverted to a short-cut nitrification and denitrification reaction tower through an inlet water tank, the biogas slurry is subjected to nitrification and denitrification treatment by the short-cut nitrification and denitrification reaction tower, the biogas slurry after nitrification and denitrification treatment is precipitated in a sedimentation tank, the biogas slurry is diverted through an intermediate water tank, the biogas slurry is subjected to cell-immobilized anaerobic ammonium oxidation treatment by a cell-immobilized anaerobic ammonium oxidation reactor, and finally discharged through an outlet water tank;

[0008] The nitrification and denitrification treatment requires strict control of the NO2 in the short-range nitrification and denitrification reaction tower. - -N and NH4 + -N ratio is 1 to 1.5:1, and NO2 - -N accumulation rate>95%.

[0009] Furthermore, the method comprises the following steps:

[0010] S1. Short-cut nitrification and denitrification sludge inoculation: aerobic sludge from a sewage treatment plant is inoculated into the short-cut nitrification and denitrification reaction tower to maintain the aerobic sludge concentration in the short-cut nitrification and denitrification reaction tower at 3000-6000 mg / L;

[0011] S2, nitrification and denitrification treatment:

[0012] S2-1. Pre-start of the short-range nitrification and denitrification reaction tower: pump the biogas slurry in the inlet tank into the short-range nitrification and denitrification reaction tower, carry out nitrification and denitrification treatment in the short-range nitrification and denitrification reaction tower, return the treated biogas slurry at the top outlet of the short-range nitrification and denitrification reaction tower to the bottom inlet of the short-range nitrification and denitrification reaction tower, and detect the pollutant concentration inside the short-range nitrification and denitrification reaction tower in real time. - -N: NH4 + -N is 1 to 1.5:1, and NO2 - -When the N accumulation rate is greater than 95%, the short-range nitrification and denitrification reaction tower is pre-started successfully;

[0013] S2-2, continuous treatment: aeration is performed inside the short-range nitrification and denitrification reaction tower, and biogas slurry is continuously pumped in. The treated biogas slurry is pumped into the sedimentation tank. After the mud and water are separated, the biogas slurry enters the intermediate water tank for the next step of treatment;

[0014] During the cell-immobilized anaerobic ammonium oxidation treatment, it is necessary to strengthen the inoculation of the sludge inside the cell-immobilized anaerobic ammonium oxidation reactor:

[0015] S3, cell-immobilized anaerobic ammonium oxidation sludge enhanced inoculation: the anaerobic ammonium oxidation granular sludge is dispersed into flocculent biomass for standby use, equal volumes of polyvinyl alcohol solution and sodium alginate solution are mixed evenly to prepare PVA-SA immobilized support liquid, and then the PVA-SA immobilized support liquid is sterilized at high temperature and cooled to room temperature for standby use, the flocculent biomass is slowly added to the PVA-SA immobilized support liquid, and biochar is added at the same time, the mass ratio of PVA-SA immobilized support liquid, flocculent biomass and biochar is 7-9:1:8-10, after mixing evenly, the obtained mixture is dispersed and dripped into several polyurethane sponge blocks, and then the polyurethane sponge blocks are placed in a cell-immobilized anaerobic ammonium oxidation reactor, and the concentration of anaerobic ammonium oxidation granular sludge in the cell-immobilized anaerobic ammonium oxidation reactor is 6000-20000 mg / L;

[0016] S4. Cell-immobilized anaerobic ammonium oxidation treatment:

[0017] S4-1. Pre-start of the cell-immobilized anaerobic ammonium oxidation reactor: pump the biogas slurry in the intermediate water tank into the cell-immobilized anaerobic ammonium oxidation reactor, react in the cell-immobilized anaerobic ammonium oxidation reactor, and return the biogas slurry treated at the outlet to the bottom inlet of the cell-immobilized anaerobic ammonium oxidation reactor. When the total nitrogen of the wastewater treated at the outlet is less than 70 mg / L, the pre-start of the cell-immobilized anaerobic ammonium oxidation reactor is successful.

[0018] S4-2. Continuous treatment: Continuously pump in the biogas slurry. The hydraulic retention time of the wastewater inside the cell-immobilized anaerobic ammonium oxidation reactor is 16 to 18 hours. The rising flow rate is 3 to 5 m / h. The wastewater treated by the cell-immobilized anaerobic ammonium oxidation reactor is pumped into the outlet tank for discharge.

[0019] Furthermore, the NH4 in the initial ammonia nitrogen-containing wastewater in the water inlet tank is adjusted in S2-1. + -N concentration is 400~1600mg / L, COD concentration is 500~3500mg / L, NO2 - -N concentration is 0~30mg / L, NO3 - -N concentration is 0~30mg / L.

[0020] Note: By limiting the pollutant concentration of the initial ammonia nitrogen-containing wastewater applicable to the present invention, it can be seen that the method of the present invention is applicable to a wide range of wastewater ammonia nitrogen content and has strong practicality.

[0021] Furthermore, the aeration method in S2-2 is micro-aeration, the acid and alkali solution is hydrochloric acid solution or sodium hydroxide solution, the dissolved oxygen is controlled at 0.3-1.5 mg / L during aeration inside the short-range nitrification and denitrification reaction tower, the sludge retention time is 25-30 days, the hydraulic retention time is 70-72 hours, the discharge return ratio is controlled to be 500%, the discharge return ratio of the recycled sludge obtained by mud and water separation in the sedimentation tank is 100%, the recycled sludge is reinjected into the short-range nitrification and denitrification reaction tower, and the acid and alkali solution is added to the intermediate water tank to adjust the wastewater pH to 7.5-8.

[0022] Furthermore, the moisture content of the anaerobic ammonium oxidation granular sludge in S3 is 90-93%, the VSS / TSS is 0.8-1, and the average diameter of the flocculent biomass is less than 100 μm.

[0023] Description: By optimizing the average diameter of flocculent biomass, short-range nitrification and denitrification can be better achieved.

[0024] Furthermore, the mass concentration of the polyvinyl alcohol solution in S3 is 6%, the mass concentration of the sodium alginate solution is 2%, the high temperature sterilization temperature is 120-130°C, the sterilization time is 30-40 minutes, and the room temperature is 25-28°C.

[0025] Furthermore, the biochar in S3 is corn straw biochar.

[0026] Furthermore, the polyurethane sponge block in S3 is a cube structure with a side length of 1.5 to 3 cm. After the mixture is dispersed and dripped into a plurality of polyurethane sponge blocks, all the polyurethane sponge blocks are reinforced and fixed, and the filling volume of all the polyurethane sponge blocks in the cell-immobilized anaerobic ammonia oxidation reactor accounts for 30 to 70%.

[0027] Preferably, during the strengthening fixation, all the polyurethane sponge blocks are divided into two parts, one of which is subjected to deep-cryogenic strengthening fixation, and the other is subjected to general strengthening fixation. The ratio of the obtained deep-cryogenic strengthening fixed polyurethane sponge blocks to the general strengthening fixed polyurethane sponge blocks is 3:7. The deep-cryogenic strengthening fixation is to subject the polyurethane sponge blocks to liquid nitrogen quenching treatment for 15 to 30 minutes. The general strengthening fixation is to immerse the polyurethane sponge blocks in a CaCl2 solution with a mass concentration of 4% and fix them at 4°C for 12 hours. When filling, the polyurethane sponge blocks subjected to deep-cryogenic strengthening fixation are placed on the periphery, and the polyurethane sponge blocks subjected to general strengthening fixation are placed on the inner side of the polyurethane sponge blocks subjected to deep-cryogenic strengthening fixation.

[0028] The present invention also provides an application of a method for treating biogas slurry by combining short-range nitrification and denitrification with cell-immobilized anaerobic ammonia oxidation, and the method is applied to denitrification treatment of biogas slurry in pig farms.

[0029] The beneficial effects of the present invention are:

[0030] (1) The method of treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation is applied to the treatment of high-ammonia nitrogen wastewater. Compared with the traditional nitrification and denitrification treatment, the oxygen supply is saved by 40-60%, the COD demand is reduced by 100%, and the sludge production is reduced by 60-90%. Compared with the general short-cut nitrification and denitrification-anaerobic ammonium oxidation technology, NO2 - -N / NH4 + The -N ratio can be stably and conveniently controlled, NOB can be effectively inhibited, the enrichment rate of AnAOB is accelerated, and the resistance to factors such as heavy metals and antibiotics is improved.

[0031] (2) The method of treating biogas sludge by short-range nitrification and denitrification combined with cell-immobilized anaerobic ammonium oxidation (ANAOMOX) of the present invention has optimized the compounding of ANAOMOX granular sludge in the cell-immobilized ANAOMOX reactor, further improving the effect of the cell-immobilized ANAOMOX treatment. At the same time, the two enhanced fixation methods of the polyurethane sponge block are used in combination, which can make the polyurethane sponge block fixed by deep cold have a certain sustained release effect, and also make the entire cell-immobilized ANAOMOX reaction more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the reactor components in the method for treating biogas slurry by combining short-range nitrification and denitrification with cell-immobilized anaerobic ammonia oxidation of the present invention;

[0033] Figure 2 It is a schematic diagram of the placement structure of deep-cold enhanced fixed polyurethane sponge blocks and general enhanced fixed polyurethane sponge blocks in the cell-immobilized anaerobic ammonium oxidation reactor in the method for treating biogas slurry by short-range nitrification and denitrification combined with cell-immobilized anaerobic ammonium oxidation of the present invention;

[0034] Figure 3 This is the microbial community analysis at the genus level of each reactor sample in Experimental Example 1 of the present invention.

[0035] Among them, 1-water inlet tank, 2-short-range nitrification and denitrification reaction tower, 3-sedimentation tank, 4-intermediate water tank, 5-cell-immobilized anaerobic ammonia oxidation reactor, 6-outlet water tank, 7-deep-cold enhanced fixed polyurethane sponge block, 8-general enhanced fixed polyurethane sponge block. DETAILED DESCRIPTION

[0036] Example 1

[0037] The method for treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation is realized based on a reactor assembly, wherein the reactor assembly comprises an inlet water tank 1, a short-cut nitrification and denitrification reaction tower 2, a sedimentation tank 3, an intermediate water tank 4, a cell-immobilized anaerobic ammonium oxidation reactor 5 and an outlet water tank 6 which are connected in sequence;

[0038] The biogas slurry is guided to the short-range nitrification and denitrification reaction tower 2 through the inlet water tank 1, the biogas slurry is subjected to nitrification and denitrification treatment through the short-range nitrification and denitrification reaction tower 2, the biogas slurry after the nitrification and denitrification treatment is precipitated through the sedimentation tank 3, guided through the intermediate water tank 4, subjected to cell-immobilized anaerobic ammonium oxidation treatment through the cell-immobilized anaerobic ammonium oxidation reactor 5, and finally discharged through the outlet water tank 6;

[0039] During nitrification and denitrification treatment, it is necessary to control the NO2 inside the short-range nitrification and denitrification reaction tower 2 - -N and NH4 + -N ratio is 1 to 1.5:1, and NO2 - -N accumulation rate>95%.

[0040] The specific steps include:

[0041] S1. Inoculation of short-cut nitrification and denitrification sludge: Inoculate the short-cut nitrification and denitrification reaction tower 2 with aerobic sludge from the sewage treatment plant, so that the concentration of aerobic sludge in the short-cut nitrification and denitrification reaction tower 2 is maintained at 4000 mg / L;

[0042] S2, nitrification and denitrification treatment:

[0043] S2-1, short-cut nitrification and denitrification reaction tower 2 pre-start: adjust the NH4 + -N concentration is 800mg / L, COD concentration is 2000mg / L, NO2 - -N concentration is 14mg / L, NO3 - -N concentration is 16mg / L, the wastewater containing ammonia nitrogen in the inlet tank 1 is pumped into the short-range nitrification and denitrification reaction tower 2, and nitrification and denitrification treatment is carried out in the short-range nitrification and denitrification reaction tower 2, and the wastewater containing ammonia nitrogen treated at the top outlet of the short-range nitrification and denitrification reaction tower 2 is returned to the bottom inlet of the short-range nitrification and denitrification reaction tower 2, and the pollutant concentration inside the short-range nitrification and denitrification reaction tower 2 is detected in real time. When the NO2 - -N: NH4 + -N is 1.2:1, and NO2 - -When the N accumulation rate was 98%, the short-range nitrification and denitrification reaction tower 2 was pre-started successfully;

[0044] S2-2, continuous treatment: aeration is performed inside the short-cut nitrification and denitrification reaction tower 2, micro-aerobic aeration is adopted as the aeration mode, the dissolved oxygen is controlled at 1 mg / L, the sludge retention time is 28 days, the hydraulic retention time is 72 hours, the discharge reflux ratio of the first reflux pump is controlled to be 500%, and the discharge reflux ratio of the sludge reflux pump is controlled to be 100%, and the ammonia nitrogen-containing wastewater treated at the top outlet of the short-cut nitrification and denitrification reaction tower 2 is pumped into the sedimentation tank 3, and the reused sludge and wastewater are obtained after the mud and water separation, and the reused sludge is injected back into the short-cut nitrification and denitrification reaction tower 2, and the wastewater is pumped into the intermediate water tank 4, and an acid and alkali solution is added to the intermediate water tank 4 to adjust the pH value of the wastewater to 7.6, and the acid and alkali solution is a hydrochloric acid solution or a sodium hydroxide solution;

[0045] The pH, dissolved oxygen, redox potential, ammonia nitrogen concentration and nitrite concentration in water are monitored by pH meter, dissolved oxygen meter, redox potential meter, ammonia nitrogen probe and nitrite probe, and the air pump and gas flow valve are controlled by programmable logic controller

[0046] When NO2 is detected in the outlet water - -N: NH4 + When -N is greater than 1.5:1, the air pump and gas flow valve are controlled by the programmable logic controller to reduce the gas flow. - -N: NH4 + -When N is less than 1:1, the air pump and gas flow valve of the micro-oxygen aeration are controlled by the programmable logic controller to increase the gas flow;

[0047] During the cell-immobilized anaerobic ammonium oxidation treatment, it is necessary to strengthen the inoculation of the sludge inside the cell-immobilized anaerobic ammonium oxidation reactor 5:

[0048] S3. Cell-immobilized anaerobic ammonium oxidation sludge inoculation: The anaerobic ammonium oxidation granular sludge was dispersed into flocculent biomass for standby use. The moisture content of the anaerobic ammonium oxidation granular sludge was 91.9%, the VSS / TSS was 0.89, and the average diameter of the flocculent biomass was 94 μm. Equal volumes of polyvinyl alcohol solution and sodium alginate solution were mixed evenly to prepare PVA-SA immobilization support liquid. The mass concentration of the polyvinyl alcohol solution was 6%, and the mass concentration of the sodium alginate solution was 2%. The PVA-SA immobilization support liquid was then sterilized by heating at 125°C in an autoclave. 35min, cooled to room temperature for standby use, the room temperature is 27°C, the flocculent biomass is slowly added to the PVA-SA immobilized support liquid, and the biochar is corn straw biochar, the mass ratio of PVA-SA immobilized support liquid, flocculent biomass and biochar is 8:1:9, after mixing evenly, the obtained mixture is dispersed and dripped into several polyurethane sponge blocks, and then the polyurethane sponge blocks are placed in the cell-immobilized anaerobic ammonium oxidation reactor 5, and the concentration of anaerobic ammonium oxidation granular sludge in the cell-immobilized anaerobic ammonium oxidation reactor 5 is 10000mg / L;

[0049] The polyurethane sponge block is a cube structure with a side length of 2 cm. After the mixture is dispersed and dripped into a plurality of polyurethane sponge blocks, all the polyurethane sponge blocks are reinforced and fixed. The filling volume of all the polyurethane sponge blocks in the cell-immobilized anaerobic ammonium oxidation reactor 5 accounts for 50%;

[0050] During the strengthening fixation, all the polyurethane sponge blocks are divided into two parts, one of which is subjected to deep-cold strengthening fixation, and the other is subjected to general strengthening fixation. The ratio of the obtained deep-cold strengthening fixed polyurethane sponge block 7 to the general strengthening fixed polyurethane sponge block 8 is 3:7. The deep-cold strengthening fixation is to subject the polyurethane sponge block to liquid nitrogen quenching treatment for 20 minutes. The general strengthening fixation is to immerse the polyurethane sponge block in a CaCl2 solution with a mass concentration of 4% and fix it at 4°C for 12 hours. During the filling, the polyurethane sponge block subjected to deep-cold strengthening fixation is placed on the periphery, and the polyurethane sponge block subjected to general strengthening fixation is placed on the inner side of the polyurethane sponge block subjected to deep-cold strengthening fixation.

[0051] S4. Cell-immobilized anaerobic ammonium oxidation treatment:

[0052] S4-1, pre-start of the cell-immobilized anaerobic ammonium oxidation reactor 5: the wastewater in the intermediate water tank 4 is pumped into the cell-immobilized anaerobic ammonium oxidation reactor 5, the reaction is carried out in the cell-immobilized anaerobic ammonium oxidation reactor 5, and the wastewater treated at the outlet is returned to the bottom inlet of the cell-immobilized anaerobic ammonium oxidation reactor 5. When the total nitrogen content of the wastewater treated at the outlet is 66 mg / L, the pre-start of the cell-immobilized anaerobic ammonium oxidation reactor 5 is successful;

[0053] S4-2, continuous treatment: NO2 in cell-immobilized anaerobic ammonium oxidation reactor - -N and NH4 + -N is removed simultaneously and a small amount of NO3 is generated - -N, the hydraulic retention time of the wastewater inside the cell-immobilized anaerobic ammonium oxidation reactor 5 is 17h, the rising flow rate is 4m / h, and the wastewater treated by the cell-immobilized anaerobic ammonium oxidation reactor 5 is pumped into the outlet water tank 6 for discharge.

[0054] Example 2

[0055] The difference between this embodiment and embodiment 1 is that:

[0056] S1. Inoculation of short-cut nitrification and denitrification sludge: Inoculate the short-cut nitrification and denitrification reaction tower 2 with aerobic sludge from a sewage treatment plant, so that the concentration of aerobic sludge in the short-cut nitrification and denitrification reaction tower 2 is maintained at 3000 mg / L.

[0057] Example 3

[0058] The difference between this embodiment and embodiment 1 is that:

[0059] S1. Inoculation of short-cut nitrification and denitrification sludge: Inoculate the short-cut nitrification and denitrification reaction tower 2 with aerobic sludge from a sewage treatment plant, so that the concentration of aerobic sludge in the short-cut nitrification and denitrification reaction tower 2 is maintained at 6000 mg / L.

[0060] Example 4

[0061] The difference between this embodiment and embodiment 1 is that:

[0062] S2-1, short-cut nitrification and denitrification reaction tower 2 pre-start: adjust the NH4 + -N concentration is 400mg / L, COD concentration is 500mg / L, NO2 - -N concentration is 5mg / L, NO3 - -N concentration is 7mg / L, the wastewater containing ammonia nitrogen in the inlet tank 1 is pumped into the short-range nitrification and denitrification reaction tower 2, and nitrification and denitrification treatment is carried out in the short-range nitrification and denitrification reaction tower 2, and the wastewater containing ammonia nitrogen treated at the top outlet of the short-range nitrification and denitrification reaction tower 2 is returned to the bottom inlet of the short-range nitrification and denitrification reaction tower 2, and the pollutant concentration inside the short-range nitrification and denitrification reaction tower 2 is detected in real time. When the NO2 - -N: NH4 + -N is 1:1, and NO2 - -When the N accumulation rate was 96%, the short-range nitrification and denitrification reaction tower 2 was pre-started successfully;

[0063] S2-2, continuous treatment: aeration is performed inside the short-cut nitrification and denitrification reaction tower 2, micro-aerobic aeration is adopted as the aeration method, dissolved oxygen is controlled at 0.3 mg / L, sludge retention time is 25 days, hydraulic retention time is 70 hours, the discharge reflux ratio of the first reflux pump is controlled to be 500%, and the discharge reflux ratio of the sludge reflux pump is controlled to be 100%, and the ammonia nitrogen-containing wastewater treated at the top outlet of the short-cut nitrification and denitrification reaction tower 2 is pumped into the sedimentation tank 3, and recycled sludge and wastewater are obtained after mud and water separation, and the recycled sludge is injected back into the short-cut nitrification and denitrification reaction tower 2, and the wastewater is pumped into the intermediate water tank 4, and acid and alkali solution is added to the intermediate water tank 4 to adjust the pH value of the wastewater to 7.5, and the acid and alkali solution is hydrochloric acid solution or sodium hydroxide solution.

[0064] Example 5

[0065] The difference between this embodiment and embodiment 1 is that:

[0066] S2-1, short-cut nitrification and denitrification reaction tower 2 pre-start: adjust the NH4 + -N concentration is 1600mg / L, COD concentration is 3500mg / L, NO2 - -N concentration is 30mg / L, NO3 - -N concentration is 30mg / L, the wastewater containing ammonia nitrogen in the inlet tank 1 is pumped into the short-range nitrification and denitrification reaction tower 2, and nitrification and denitrification treatment is carried out in the short-range nitrification and denitrification reaction tower 2, and the wastewater containing ammonia nitrogen treated at the top outlet of the short-range nitrification and denitrification reaction tower 2 is returned to the bottom inlet of the short-range nitrification and denitrification reaction tower 2, and the pollutant concentration inside the short-range nitrification and denitrification reaction tower 2 is detected in real time. When the NO2 - -N: NH4 + -N is 1.5:1, and NO2 - -When the N accumulation rate was 98%, the short-range nitrification and denitrification reaction tower 2 was pre-started successfully;

[0067] S2-2, continuous treatment: aeration is performed inside the short-cut nitrification and denitrification reaction tower 2, micro-aeration is adopted as the aeration method, dissolved oxygen is controlled at 1.5 mg / L, sludge retention time is 30 days, hydraulic retention time is 72 hours, the discharge reflux ratio of the first reflux pump is controlled to be 500%, and the discharge reflux ratio of the sludge reflux pump is controlled to be 100%, and the ammonia nitrogen-containing wastewater treated at the top outlet of the short-cut nitrification and denitrification reaction tower 2 is pumped into the sedimentation tank 3, and recycled sludge and wastewater are obtained after mud and water separation, and the recycled sludge is injected back into the short-cut nitrification and denitrification reaction tower 2, and the wastewater is pumped into the intermediate water tank 4, and acid and alkali solution is added to the intermediate water tank 4 to adjust the pH value of the wastewater to 8, and the acid and alkali solution is hydrochloric acid solution or sodium hydroxide solution.

[0068] Example 6

[0069] The difference between this embodiment and embodiment 1 is that:

[0070] S3. Cell-immobilized anaerobic ammonium oxidation sludge inoculation: The anaerobic ammonium oxidation granular sludge was dispersed into flocculent biomass for standby use. The moisture content of the anaerobic ammonium oxidation granular sludge was 90%, the VSS / TSS was 0.8, and the average diameter of the flocculent biomass was 90 μm. Equal volumes of polyvinyl alcohol solution and sodium alginate solution were mixed evenly to prepare PVA-SA immobilization support liquid. The mass concentration of the polyvinyl alcohol solution was 6%, and the mass concentration of the sodium alginate solution was 2%. The PVA-SA immobilization support liquid was then sterilized by heating at 120°C in an autoclave for 3 hours. 0min, cooled to room temperature for standby use, the room temperature is 25°C, the flocculent biomass is slowly added to the PVA-SA immobilized support liquid, and the biochar is corn straw biochar, the mass ratio of PVA-SA immobilized support liquid, flocculent biomass and biochar is 7:1:8, after mixing evenly, the obtained mixture is dispersed and dripped into several polyurethane sponge blocks, and then the polyurethane sponge blocks are placed in the cell-immobilized anaerobic ammonium oxidation reactor 5, and the concentration of anaerobic ammonium oxidation granular sludge in the cell-immobilized anaerobic ammonium oxidation reactor 5 is 6000mg / L;

[0071] The polyurethane sponge block is a cube structure with a side length of 1.5 cm. After the mixture is dispersed and dripped into a number of polyurethane sponge blocks, all the polyurethane sponge blocks are reinforced and fixed. The filling volume of all the polyurethane sponge blocks in the cell-immobilized anaerobic ammonia oxidation reactor 5 accounts for 30%.

[0072] Example 7

[0073] The difference between this embodiment and embodiment 1 is that:

[0074] S3. Cell-immobilized anaerobic ammonium oxidation sludge inoculation: The anaerobic ammonium oxidation granular sludge was dispersed into flocculent biomass for standby use. The moisture content of the anaerobic ammonium oxidation granular sludge was 93%, the VSS / TSS was 1, and the average diameter of the flocculent biomass was 95 μm. Equal volumes of polyvinyl alcohol solution and sodium alginate solution were mixed evenly to prepare PVA-SA immobilization support liquid. The mass concentration of the polyvinyl alcohol solution was 6%, and the mass concentration of the sodium alginate solution was 2%. The PVA-SA immobilization support liquid was then sterilized by heating at 130°C in an autoclave for 40 min. in, cooled to room temperature for standby use, the room temperature is 28°C, the flocculent biomass is slowly added to the PVA-SA immobilized support liquid, and the biochar is corn straw biochar, the mass ratio of PVA-SA immobilized support liquid, flocculent biomass and biochar is 9:1:10, after mixing evenly, the obtained mixture is dispersed and dripped into several polyurethane sponge blocks, and then the polyurethane sponge blocks are placed in the cell-immobilized anaerobic ammonium oxidation reactor 5, and the concentration of anaerobic ammonium oxidation granular sludge in the cell-immobilized anaerobic ammonium oxidation reactor 5 is 20000 mg / L;

[0075] The polyurethane sponge block is a cube structure with a side length of 3 cm. After the mixture is dispersed and dripped into a number of polyurethane sponge blocks, all the polyurethane sponge blocks are reinforced and fixed. The filling volume of all the polyurethane sponge blocks in the cell-immobilized anaerobic ammonia oxidation reactor 5 accounts for 70%.

[0076] Note: When the pollutant concentration in the treated sewage is high, the concentration of the anaerobic ammonium oxidation granular sludge in the cell-immobilized anaerobic ammonium oxidation reactor 5 should be appropriately increased. At the same time, the size of the polyurethane sponge block should also be appropriately increased, and the volume proportion of the polyurethane sponge block should also be increased.

[0077] Example 8

[0078] The difference between this embodiment and embodiment 1 is that:

[0079] During the strengthening fixation, all the polyurethane sponge blocks are divided into two parts, one of which is subjected to deep-cold strengthening fixation, and the other is subjected to general strengthening fixation. The ratio of the obtained deep-cold strengthening fixed polyurethane sponge block 7 to the general strengthening fixed polyurethane sponge block 8 is 3:7. The deep-cold strengthening fixation is to subject the polyurethane sponge block to a liquid nitrogen quenching treatment for 15 minutes. The general strengthening fixation is to immerse the polyurethane sponge block in a CaCl2 solution with a mass concentration of 4% and fix it at 4°C for 12 hours. When filling, the polyurethane sponge blocks subjected to deep-cold strengthening fixation are placed on the periphery, and the polyurethane sponge blocks subjected to general strengthening fixation are placed on the inner side of the polyurethane sponge blocks subjected to deep-cold strengthening fixation.

[0080] Example 9

[0081] The difference between this embodiment and embodiment 1 is that:

[0082] During the strengthening fixation, all the polyurethane sponge blocks are divided into two parts, one of which is subjected to deep-cold strengthening fixation, and the other is subjected to general strengthening fixation. The ratio of the obtained deep-cold strengthening fixed polyurethane sponge block 7 to the general strengthening fixed polyurethane sponge block 8 is 3:7. The deep-cold strengthening fixation is to subject the polyurethane sponge block to a liquid nitrogen quenching treatment for 30 minutes. The general strengthening fixation is to immerse the polyurethane sponge block in a CaCl2 solution with a mass concentration of 4% and fix it at 4°C for 12 hours. When filling, the polyurethane sponge blocks subjected to deep-cold strengthening fixation are placed on the periphery, and the polyurethane sponge blocks subjected to general strengthening fixation are placed on the inner side of the polyurethane sponge blocks subjected to deep-cold strengthening fixation.

[0083] Example 10

[0084] The difference between this embodiment and embodiment 1 is that:

[0085] S4-1, pre-start of the cell-immobilized anaerobic ammonium oxidation reactor 5: the wastewater in the intermediate water tank 4 is pumped into the cell-immobilized anaerobic ammonium oxidation reactor 5, the reaction is carried out in the cell-immobilized anaerobic ammonium oxidation reactor 5, and the wastewater treated at the outlet is returned to the bottom inlet of the cell-immobilized anaerobic ammonium oxidation reactor 5. When the total nitrogen content of the wastewater treated at the outlet is 65 mg / L, the pre-start of the cell-immobilized anaerobic ammonium oxidation reactor 5 is successful;

[0086] S4-2, continuous treatment: the hydraulic retention time of the wastewater inside the cell-immobilized anaerobic ammonium oxidation reactor 5 is 16 hours, the rising flow rate is 3 m / h, and the wastewater treated by the cell-immobilized anaerobic ammonium oxidation reactor 5 is pumped into the outlet water tank 6 for discharge.

[0087] Embodiment 11

[0088] The difference between this embodiment and embodiment 1 is that:

[0089] S4-1, pre-start of the cell-immobilized anaerobic ammonium oxidation reactor 5: the wastewater in the intermediate water tank 4 is pumped into the cell-immobilized anaerobic ammonium oxidation reactor 5, the reaction is carried out in the cell-immobilized anaerobic ammonium oxidation reactor 5, and the wastewater treated at the outlet is returned to the bottom water inlet of the cell-immobilized anaerobic ammonium oxidation reactor 5. When the total nitrogen content of the wastewater treated at the outlet is 68 mg / L, the pre-start of the cell-immobilized anaerobic ammonium oxidation reactor 5 is successful;

[0090] S4-2. Continuous treatment: The hydraulic retention time of the wastewater in the cell-immobilized anaerobic ammonium oxidation reactor 5 is 18 hours, and the rising flow rate is 5 m / h. The wastewater treated by the cell-immobilized anaerobic ammonium oxidation reactor 5 is pumped into the outlet water tank 6 for discharge.

[0091] Example 12

[0092] This embodiment is an application of the method for treating biogas slurry by combining short-range nitrification and denitrification with cell-immobilized anaerobic ammonia oxidation in Embodiment 1, and the method is applied to the high-efficiency and low-power denitrification treatment of biogas slurry in pig farms.

[0093] Experimental Example 1

[0094] The ammonia nitrogen-containing wastewater was treated according to the method in Example 1, and after the reactor assembly was running stably, the COD concentration in the final effluent of the process section was 400-450 mg / L, and the NH4 + -N concentration is less than 15mg / L, NO2 - -N concentration is less than 15mg / L, NO3 - -N concentration is less than 40mg / L, total nitrogen concentration is less than 70mg / L, and the remaining COD is difficult-to-biodegrade organic matter, which requires subsequent physical and chemical means to remove in order to achieve the wastewater denitrification goal.

[0095] Nitrification consumes alkalinity, which leads to a decrease in pH, while denitrification and ANAMMOX generate alkalinity, which leads to an increase in pH. In addition, the increase in ARE can be attributed to nitrification and ANAMMOX reactions, and the increase in NRE can be attributed to denitrification and ANAMMOX reactions.

[0096] At the same time, we also compared the real wastewater with the wastewater configured in the laboratory. The difference between Comparative Example 1 and Example 1 is that simulated wastewater is used. The cell-immobilized anaerobic ammonia oxidation reactor 5 inoculated by cell immobilization has a higher resistance to adverse factors in real wastewater than granular sludge; compared with the simulated wastewater, the effluent NH4 + -N and NO2 - -N concentrations increased because real wastewater contained higher concentrations of inhibitory factors (such as heavy metals and antibiotics), and these interfering factors aggravated the inhibition of AnAOB.

[0097] In addition, we also compared the reactor without biochar addition as comparative example 2 with Example 1, and observed that the NH4 + -N and NO2 - The rate of increase of -N concentration was significantly slower than that of the reactor in Example 1, which indicates that the additional addition of biochar during the cell immobilization process is beneficial to improving the resistance of AnAOB to related inhibitory factors in pig farm biogas slurry.

[0098] like Figure 3As shown in the figure, we also studied the relative abundance of different microorganisms at the phylum level. The main dominant phyla in the four sludge samples were Chloroflexi, Proteobacteria and Bacteroidetes, and the sum of their abundances was between 59.39% and 68.79%, while the relative abundance of Planctomycetota, which is related to AnAOB, was about 2% in the inoculated sludge and the reactor.

[0099] Proteobacteria and Chloroflexi usually coexist with Planctomyces in the cell-immobilized anaerobic ammonium oxidation reactor 5. They can use the nitrite and nitrate present in the reactor to consume the organic matter produced by the microbial growth and metabolism process, thereby preventing the accumulation of organic matter from inhibiting AnAOB, and playing an important role in maintaining the stable operation performance of the system. In addition, Chloroflexi also plays an important role in the granulation process, which helps to maintain sludge granulation and stable granular sludge. And studies have shown that many nitrifying and denitrifying bacteria belong to Proteobacteria and Bacteroidetes. Therefore, the high proportion of these three bacterial phyla in the cell-immobilized anaerobic ammonium oxidation reactor 5 explains the occurrence of nitrification and denitrification in each reactor.

[0100] Experimental Example 2

[0101] Ammonia nitrogen-containing wastewater was treated according to the method in Example 1 and compared with Comparative Example 3. The difference between Comparative Example 3 and Example 1 is that all polyurethane sponge blocks were generally reinforced and fixed;

[0102] When the influent is real wastewater, the nitrogen removal load (NRR) of the reactor changes with the number of treatment days as shown in Table 1.

[0103] Table 1 Comparison of NRR between Example 1 and Comparative Example 3

[0104]

[0105] It can be found that under the same NLR conditions, the NRR of the two groups of reactors showed a significant decline, and the denitrification performance of the reactors began to gradually deteriorate, indicating that real wastewater will have a stronger inhibitory effect on AnAOB, and the activity of AnAOB has seriously declined. The actual wastewater contains substances that have an inhibitory effect on AnAOB, and the enhanced sustained release of AnAOB in Example 1 can effectively alleviate this problem, and the NRR can be maintained at a high level in the later stage of treatment, while a larger decline occurred in Comparative Example 3. Therefore, the enhanced fixation method in Example 1 will be more helpful to realize the engineering application of ANAMMOX technology in the denitrification treatment of pig farm biogas slurry.

Claims

1. A method for treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation, comprising: directing the biogas slurry to a short-cut nitrification and denitrification reaction tower (2) through an inlet water tank (1), subjecting the biogas slurry to nitrification and denitrification treatment in the short-cut nitrification and denitrification reaction tower (2), precipitating the biogas slurry after nitrification and denitrification treatment in a sedimentation tank (3), directing the biogas slurry through an intermediate water tank (4), subjecting the biogas slurry to cell-immobilized anaerobic ammonium oxidation treatment in a cell-immobilized anaerobic ammonium oxidation reactor (5), and finally discharging the biogas slurry through an outlet water tank (6); It is characterized in that The nitrification and denitrification treatment needs to control the NO2 inside the short-range nitrification and denitrification reaction tower (2). - -N and NH4 + -N ratio is 1 to 1.5:1, and NO2 - -N accumulation rate>95%.

2. The method for treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation according to claim 1, characterized in that: The method comprises the following steps: S1. Inoculation of short-cut nitrification and denitrification sludge: Inoculating the short-cut nitrification and denitrification reaction tower (2) with aerobic sludge from a sewage treatment plant, so that the concentration of aerobic sludge in the short-cut nitrification and denitrification reaction tower (2) is maintained at 3000-6000 mg / L; S2, nitrification and denitrification treatment: S2-1, Pre-start of the short-range nitrification and denitrification reaction tower (2): The biogas slurry is pumped into the short-range nitrification and denitrification reaction tower (2), and all the biogas slurry at the outlet is refluxed, and the pollutant concentration is detected in real time. When the NO2 - -N: NH4 + -N is 1 to 1.5:1, and NO2 - - When the N accumulation rate is greater than 95%, the short-range nitrification and denitrification reaction tower (2) is pre-started successfully; S2-2, continuous treatment: aeration is performed inside the short-range nitrification and denitrification reaction tower (2), and biogas slurry is continuously pumped in. The treated biogas slurry is pumped into a sedimentation tank (3). After the mud and water are separated, the biogas slurry enters an intermediate water tank (4) for the next step of treatment; During the cell-immobilized anaerobic ammonium oxidation treatment, it is necessary to perform enhanced inoculation on the sludge inside the cell-immobilized anaerobic ammonium oxidation reactor (5): S3, cell-immobilized anaerobic ammonium oxidation sludge enhanced inoculation: the anaerobic ammonium oxidation granular sludge is dispersed into flocculent biomass, equal volumes of polyvinyl alcohol solution and sodium alginate solution are mixed evenly to prepare PVA-SA immobilized support liquid, the PVA-SA immobilized support liquid is sterilized at high temperature and then cooled to room temperature, the flocculent biomass and biochar are added, the mass ratio of PVA-SA immobilized support liquid, flocculent biomass and biochar is 7-9:1:8-10, the mixture is evenly mixed and then dripped into a plurality of polyurethane sponge blocks, the polyurethane sponge blocks are placed in a cell-immobilized anaerobic ammonium oxidation reactor (5), and the concentration of anaerobic ammonium oxidation granular sludge in the cell-immobilized anaerobic ammonium oxidation reactor (5) is 6000-20000 mg / L; S4. Cell-immobilized anaerobic ammonium oxidation treatment: S4-1, pre-starting of the cell-immobilized anaerobic ammonium oxidation reactor (5): the biogas slurry is pumped into the cell-immobilized anaerobic ammonium oxidation reactor (5), and all the biogas slurry at the outlet is refluxed, and the pollutant concentration is detected in real time. When the total nitrogen of the wastewater treated at the outlet is less than 70 mg / L, the pre-starting of the cell-immobilized anaerobic ammonium oxidation reactor (5) is successful; S4-2, continuous treatment: The biogas slurry is continuously pumped in, and the hydraulic retention time of the wastewater inside the cell-immobilized anaerobic ammonium oxidation reactor (5) is 16 to 18 hours, the rising flow rate is 3 to 5 m / h, and finally discharged through the outlet water tank (6).

3. The method for treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation according to claim 2, characterized in that: The NH4 content of the initial biogas slurry in the inlet water tank (1) is adjusted in S2-1. + -N concentration is 400~1600mg / L, COD concentration is 500~3500mg / L, NO2 - -N concentration is 0~30mg / L, NO3 - -N concentration is 0~30mg / L.

4. The method for treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation according to claim 2, characterized in that: The aeration method in S2-2 is micro-aerobic aeration, the acid and alkali solution is hydrochloric acid solution or sodium hydroxide solution, the dissolved oxygen in the short-range nitrification and denitrification reaction tower (2) is controlled to be 0.3-1.5 mg / L during aeration, the sludge retention time is 25-30 days, the hydraulic retention time is 70-72 hours, the discharge return ratio is controlled to be 500%, the discharge return ratio of the recycled sludge obtained by mud and water separation in the sedimentation tank (3) is 100%, the recycled sludge is reinjected into the short-range nitrification and denitrification reaction tower (2), and the acid and alkali solution is added to the intermediate water tank (4) to adjust the pH of the wastewater to 7.5-8.

5. The method for treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation according to claim 2, characterized in that: The moisture content of the anaerobic ammonium oxidation granular sludge in the S3 is 90-93%, the VSS / TSS is 0.8-1, and the average diameter of the flocculent biomass is less than 100 μm.

6. The method for treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation according to claim 2, characterized in that: The mass concentration of the polyvinyl alcohol solution in S3 is 6%, the mass concentration of the sodium alginate solution is 2%, the high temperature sterilization temperature is 120-130°C, the sterilization time is 30-40 minutes, and the room temperature is 25-28°C.

7. The method for treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation according to claim 2, characterized in that: The biochar in S3 is corn straw biochar.

8. The method for treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation according to claim 2, characterized in that: The polyurethane sponge block in S3 is a cubic structure with a side length of 1.5 to 3 cm. After the mixture is dispersed and dripped into a plurality of polyurethane sponge blocks, all the polyurethane sponge blocks are reinforced and fixed. The filling volume of all the polyurethane sponge blocks in the cell-immobilized anaerobic ammonium oxidation reactor (5) accounts for 30 to 70%.

9. The method for treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation according to claim 8, characterized in that: During the strengthening fixation, all the polyurethane sponge blocks are divided into two parts, one of which is subjected to deep-cold strengthening fixation, and the other is subjected to general strengthening fixation. The ratio of the obtained deep-cold strengthening fixed polyurethane sponge block (7) to the general strengthening fixed polyurethane sponge block (8) is 3:

7. The deep-cold strengthening fixation is to subject the polyurethane sponge block to a liquid nitrogen quenching treatment for 15 to 30 minutes. The general strengthening fixation is to immerse the polyurethane sponge block in a CaCl2 solution with a mass concentration of 4% and fix it at 4°C for 12 hours. During filling, the polyurethane sponge block subjected to deep-cold strengthening fixation is placed on the periphery, and the polyurethane sponge block subjected to general strengthening fixation is placed on the inner side of the polyurethane sponge block subjected to deep-cold strengthening fixation.

10. Application of the method for treating biogas slurry by combining short-cut nitrification and denitrification with cell-immobilized anaerobic ammonium oxidation according to claim 1, characterized in that: The method is applied to the denitrification treatment of biogas slurry in pig farms.

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