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

Abstract

The application discloses a method for treating biogas slurry by short-cut nitrification and denitrification combined with cell immobilized anaerobic ammonia oxidation, and is realized based on a reactor assembly and comprises the following steps: S1, short-cut nitrification and denitrification sludge inoculation; S2, nitrification and denitrification treatment: S2-1, pre-starting of a short-cut nitrification and denitrification reaction tower; S2-2, continuous treatment; S3, cell immobilized anaerobic ammonia oxidation sludge inoculation; S4, cell immobilized anaerobic ammonia oxidation treatment; S4-1, pre-starting of a cell immobilized anaerobic ammonia oxidation reactor; and S4-2, continuous treatment. The application is applied to the treatment of high-ammonia-nitrogen wastewater, and compared with the traditional nitrification and denitrification method, 40-60% of oxygen supply is saved, 100% of COD demand is reduced, and 60-90% of sludge yield is reduced; compared with the general short-cut nitrification and denitrification-anaerobic ammonia oxidation technology, the NO2 ‑ ‑N / NH4 + 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 present application relates to the technical field of ammonia-nitrogen wastewater treatment, in particular to a method for treating biogas slurry by short-cut nitrification-denitrification combined with cell immobilization anaerobic ammonia oxidation. BACKGROUND

[0002] In recent years, sewage treatment technology, especially the treatment of high ammonia-nitrogen wastewater, has attracted the attention and research of human beings. Among the many sewage treatment technologies, the short-cut nitrification-denitrification combined with anaerobic ammonia 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 small sludge yield.

[0003] Among them, the short-cut nitrification-denitrification process is based on the growth rate difference of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) under different temperature, dissolved oxygen (dO) and pH related environmental factors, to complete the specific inhibition and removal of NOB, and to promote AOB to become the dominant bacteria, so as to control the traditional full nitrification in the nitrite (NO2 - -N) stage, and directly use NO2 - -N as the final electron acceptor for denitrification.

[0004] The anaerobic ammonia oxidation process is under anaerobic or anoxic conditions, anaerobic ammonia oxidation bacteria (AnAOB) uses NO2 - -N as the electron acceptor, ammonium (NH4 + -N) as the electron donor, and directly converts them into nitrogen (N2) and part of nitrate (NO3 - -N), however, both of them often face challenges such as difficulty in stable control of NO2 - -N / NH4 + -N ratio, NOB adaptation inhibition, long growth cycle of AnAOB, slow enrichment and extreme sensitivity to environmental factors such as heavy metals and antibiotics. SUMMARY

[0005] In view of the above problems, the present application provides a method for treating biogas slurry by short-cut nitrification-denitrification combined with cell immobilization anaerobic ammonia oxidation.

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

[0007] The method for treating biogas slurry by short-cut nitrification and denitrification combined with cell immobilized anaerobic ammonia oxidation, the biogas slurry is guided to the short-cut nitrification and denitrification reactor through the water inlet tank, the biogas slurry is treated by nitrification and denitrification through the short-cut nitrification and denitrification reactor, the biogas slurry treated by nitrification and denitrification is precipitated through the sedimentation tank, the biogas slurry is guided through the intermediate water tank, the biogas slurry is treated by cell immobilized anaerobic ammonia oxidation through the cell immobilized anaerobic ammonia oxidation reactor, and finally the treated biogas slurry is discharged through the water outlet tank;

[0008] The nitrification and denitrification treatment needs to strictly control the NO2 - The ratio of -N to NH4 + The ratio of -N to NH4 - The accumulation rate of NO2

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

[0010] S1, short-cut nitrification and denitrification sludge inoculation: inoculating aerobic sludge from a sewage plant into the short-cut nitrification and denitrification reactor, so that the concentration of the aerobic sludge in the short-cut nitrification and denitrification reactor is maintained at 3000-6000 mg / L;

[0011] S2, nitrification and denitrification treatment:

[0012] S2-1, short-cut nitrification and denitrification reactor pre-start: pumping the biogas slurry in the water inlet tank into the short-cut nitrification and denitrification reactor, treating the biogas slurry by nitrification and denitrification in the short-cut nitrification and denitrification reactor, returning the biogas slurry treated at the top of the water outlet end to the bottom of the water inlet end of the short-cut nitrification and denitrification reactor, and detecting the pollutant concentration in the short-cut nitrification and denitrification reactor in real time, when the NO2 - The ratio of -N to NH4 + The ratio of -N to NH4 - When the accumulation rate of NO2

[0013] S2-2, continuous treatment: aerating the short-cut nitrification and denitrification reactor, continuously pumping the biogas slurry, pumping the treated biogas slurry into the sedimentation tank, and then pumping the biogas slurry into the intermediate water tank for further treatment after the sludge and water are separated;

[0014] The cell immobilized anaerobic ammonia oxidation treatment needs to strengthen the inoculation of the sludge in the cell immobilized anaerobic ammonia oxidation reactor:

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

[0016] S4, cell immobilized anaerobic ammonia oxidation treatment:

[0017] S4-1, cell immobilized anaerobic ammonia oxidation reactor pre-start: the biogas slurry in the intermediate water tank is pumped into the cell immobilized anaerobic ammonia oxidation reactor, reaction is carried out in the cell immobilized anaerobic ammonia oxidation reactor, and the treated biogas slurry at the outlet is returned to the water inlet at the bottom of the cell immobilized anaerobic ammonia oxidation reactor, when the total nitrogen of the treated wastewater at the outlet is less than 70 mg / L, the cell immobilized anaerobic ammonia oxidation reactor pre-start is successful.

[0018] S4-2, continuous treatment: the biogas slurry is continuously pumped in, the hydraulic retention time of the wastewater in the cell immobilized anaerobic ammonia oxidation reactor is 16-18 h, and the upflow velocity is 3-5 m / h, and the wastewater treated by the cell immobilized anaerobic ammonia oxidation reactor is pumped into the outlet water tank for discharge.

[0019] Further, the NH4 + -N concentration is 400-1600 mg / L, the COD concentration is 500-3500 mg / L, the NO2 - -N concentration is 0-30 mg / L, and the NO3 - -N concentration is 0-30 mg / L.

[0020] It can be seen from the limitation of the pollutant concentration of the initial ammonia-nitrogen-containing wastewater suitable for the present application that the wastewater ammonia-nitrogen content range suitable for the method of the present application is wide, and the method has strong practicability.

[0021] Further, the aeration mode in S2-2 is micro-aeration, the acid-alkali solution is hydrochloric acid solution or sodium hydroxide solution, the dissolved oxygen is controlled at 0.3-1.5 mg / L during the internal aeration of the short-cut nitrification and denitrification reaction tower, the sludge retention time is 25-30 d, the hydraulic retention time is 70-72 h, the discharge reflux ratio is controlled at 500%, the discharge reflux ratio of the recycled sludge obtained by the sludge-water separation of the sedimentation tank is 100%, the recycled sludge is injected into the short-cut nitrification and denitrification reaction tower, and the acid-alkali solution is added to the intermediate water tank to adjust the pH of the wastewater to 7.5-8.

[0022] Further, the water content of the anaerobic ammonia 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: the average diameter of the flocculent biomass is preferably selected, so that the short-cut nitrification and denitrification is better achieved.

[0024] Further, 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 ℃, the sterilization time is 30-40 min, and the normal-temperature temperature is 25-28 ℃.

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

[0026] Further, the polyurethane sponge block in S3 is a cube structure with a side length of 1.5-3 cm, the mixture is dispersed and dropped into a plurality of polyurethane sponge blocks, then all the polyurethane sponge blocks are intensively fixed, and the filling volume ratio of all the polyurethane sponge blocks in the cell immobilized anaerobic ammonia oxidation reactor is 30-70%.

[0027] Preferably, during the intensive fixing, all the polyurethane sponge blocks are divided into two parts, one part is intensively fixed by deep cooling, and the other part is intensively fixed by general fixing, the ratio of the polyurethane sponge blocks intensively fixed by deep cooling to the polyurethane sponge blocks intensively fixed by general fixing is 3:7, the polyurethane sponge blocks intensively fixed by deep cooling are treated by liquid nitrogen quenching, the treatment time is 15-30 min, the polyurethane sponge blocks intensively fixed by general fixing are soaked in a CaCl2 solution with a mass concentration of 4% and fixed at 4 ℃ for 12 h, during the filling, the polyurethane sponge blocks intensively fixed by deep cooling are placed at the outside, and the polyurethane sponge blocks intensively fixed by general fixing are placed at the inside of the polyurethane sponge blocks intensively fixed by deep cooling.

[0028] The application also provides the application of the method for treating biogas slurry by the short-cut nitrification and denitrification combined with cell immobilized anaerobic ammonia oxidation, and the method is applied to the denitrification treatment of pig farm biogas slurry.

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

[0030] (1) The short-cut nitrification and denitrification combined cell immobilization anaerobic ammonia oxidation method for treating biogas slurry of the present application is applied to the treatment of high ammonia-nitrogen wastewater, compared with the traditional nitrification and denitrification method, the oxygen supply amount 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 ammonia oxidation technology, the NO2 - -N / NH4 + The ratio of -N / NH4 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.

[0031] (2) The short-cut nitrification and denitrification combined cell immobilization anaerobic ammonia oxidation method for treating biogas slurry of the present application optimizes the anaerobic ammonia oxidation granular sludge in the cell immobilization anaerobic ammonia oxidation reactor, further improves the effect of cell immobilization anaerobic ammonia oxidation treatment, and simultaneously uses two kinds of reinforced fixation methods of polyurethane sponge block, so that the polyurethane sponge block fixed by deep cold reinforcement has a certain slow-release effect, and the whole cell immobilization anaerobic ammonia oxidation reaction is more stable. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a reactor assembly structure schematic diagram in the short-cut nitrification and denitrification combined cell immobilization anaerobic ammonia oxidation method for treating biogas slurry of the present application;

[0033] Figure 2 is a placement structure schematic diagram of deep cold reinforced polyurethane sponge block and general reinforced polyurethane sponge block in the cell immobilization anaerobic ammonia oxidation reactor in the short-cut nitrification and denitrification combined cell immobilization anaerobic ammonia oxidation method for treating biogas slurry of the present application;

[0034] Figure 3 is a horizontal microbial community analysis of each reactor sample in Example 1 of the present application.

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

[0036] Example 1

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

[0038] The biogas slurry is guided by the water inlet tank 1 to the short-cut nitrification and denitrification reaction tower 2, and is subjected to nitrification and denitrification treatment by the short-cut nitrification and denitrification reaction tower 2, and is subjected to sedimentation by the sedimentation tank 3, and is guided by the intermediate water tank 4, and is subjected to cell immobilized anaerobic ammonia oxidation treatment by the cell immobilized anaerobic ammonia oxidation reactor 5, and is finally discharged by the water outlet tank 6.

[0039] During the nitrification and denitrification treatment, the NO2 - -N and NH4 + -N ratio is 1-1.5:1, and the NO2 - -N accumulation rate is >95%.

[0040] Specifically, the method comprises the following steps:

[0041] S1, short-cut nitrification and denitrification sludge inoculation: inoculating aerobic sludge from a sewage plant into the short-cut nitrification and denitrification reaction tower 2, so that the concentration of the 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, pre-starting of the short-cut nitrification and denitrification reaction tower 2: adjusting the NH4 + -N concentration of the initial ammonia-nitrogen-containing wastewater in the water inlet tank 1 to 800 mg / L, the COD concentration to 2000 mg / L, the NO2 - -N concentration to 14 mg / L, and the NO3 - -N concentration to 16 mg / L, pumping the ammonia-nitrogen-containing wastewater in the water inlet tank 1 into the short-cut nitrification and denitrification reaction tower 2, performing nitrification and denitrification treatment in the short-cut nitrification and denitrification reaction tower 2, returning the treated ammonia-nitrogen-containing wastewater at the water outlet end of the top of the short-cut nitrification and denitrification reaction tower 2 to the water inlet end of the bottom of the short-cut nitrification and denitrification reaction tower 2, and detecting the pollutant concentration in the short-cut nitrification and denitrification reaction tower 2 in real time, when the NO2 - -N: NH4 + -N ratio is 1.2:1, and the NO2 - -N accumulation rate is 98%, the pre-starting of the short-cut nitrification and denitrification reaction tower 2 is successful;

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

[0045] The pH, dissolved oxygen, oxidation-reduction potential, ammonia-nitrogen concentration and nitrite concentration in the water are monitored by a pH meter, a dissolved oxygen detector, an oxidation-reduction potential detector, an ammonia-nitrogen probe and a nitrite probe, and the gas pump and the gas flow valve are controlled by a programmable logic controller

[0046] When it is detected that the effluent NO2 - -N: NH4 + When -N is greater than 1.5:1, the gas flow is reduced by controlling the gas pump and the gas flow valve by the programmable logic controller, and when it is detected that the effluent NO2 - -N: NH4 + When -N is less than 1:1, the gas flow of the micro-aerobic aeration is increased by controlling the gas pump and the gas flow valve by the programmable logic controller.

[0047] When the cell immobilized anaerobic ammonia oxidation is treated, the sludge in the cell immobilized anaerobic ammonia oxidation reactor 5 needs to be strengthened inoculation:

[0048] S3, cell immobilized anaerobic ammonia oxidation sludge inoculation: the anaerobic ammonia oxidation granular sludge is dispersed into flocculent biomass for use, the water content of the anaerobic ammonia oxidation granular sludge is 91.9%, the VSS / TSS is 0.89, and the average diameter of the flocculent biomass is 94 μm; an equal volume of polyvinyl alcohol solution and sodium alginate solution is mixed uniformly to prepare a PVA-SA immobilization support solution, the mass concentration of the polyvinyl alcohol solution is 6%, and the mass concentration of the sodium alginate solution is 2%; then the PVA-SA immobilization support solution is sterilized in an autoclave at a temperature of 125°C for 35 min, and cooled to room temperature for use, the room temperature is 27°C; the flocculent biomass is slowly added into the PVA-SA immobilization support solution, and biochar, which is corn straw biochar, is added at the same time; the mass ratio of the PVA-SA immobilization support solution, the flocculent biomass and the biochar is 8:1:9; after being mixed uniformly, the obtained mixture is dispersed and dripped into a plurality of polyurethane sponge blocks; then the polyurethane sponge blocks are placed in the cell immobilized anaerobic ammonia oxidation reactor 5, and the anaerobic ammonia oxidation granular sludge concentration in the cell immobilized anaerobic ammonia oxidation reactor 5 is 10000 mg / L;

[0049] The polyurethane sponge blocks are in the form of a cube 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 intensively fixed; the filling volume ratio of all the polyurethane sponge blocks in the cell immobilized anaerobic ammonia oxidation reactor 5 is 50%;

[0050] During the intensive fixing, all the polyurethane sponge blocks are divided into two parts, one part is intensively fixed by deep cooling, and the other part is intensively fixed by general fixing; the ratio of the polyurethane sponge blocks intensively fixed by deep cooling to the polyurethane sponge blocks intensively fixed by general fixing is 3:7; the polyurethane sponge blocks intensively fixed by deep cooling are treated by liquid nitrogen quenching for 20 min; the polyurethane sponge blocks intensively fixed by general fixing are soaked in a CaCl2 solution with a mass concentration of 4% and fixed at 4°C for 12 h; during the filling, the polyurethane sponge blocks intensively fixed by deep cooling are placed on the outside, and the polyurethane sponge blocks intensively fixed by general fixing are placed on the inside of the polyurethane sponge blocks intensively fixed by deep cooling;

[0051] S4, cell immobilized anaerobic ammonia oxidation treatment:

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

[0053] S4-2, continuous treatment: NO2 - -N and NH4 + -N is removed synchronously, and a small amount of NO3 - -N, the hydraulic retention time of the wastewater inside the cell-immobilized anaerobic ammonia oxidation reactor 5 is 17 h, the upflowing speed is 4 m / h, and the wastewater treated by the cell-immobilized anaerobic ammonia oxidation reactor 5 is pumped into the effluent tank 6 for discharge.

[0054] Example 2

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

[0056] S1, short-cut nitrification and denitrification sludge inoculation: the aerobic sludge from the sewage plant is inoculated into the short-cut nitrification and denitrification reactor tower 2, so that the concentration of the aerobic sludge in the short-cut nitrification and denitrification reactor tower 2 is maintained at 3000 mg / L.

[0057] Example 3

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

[0059] S1, short-cut nitrification and denitrification sludge inoculation: the aerobic sludge from the sewage plant is inoculated into the short-cut nitrification and denitrification reactor tower 2, so that the concentration of the aerobic sludge in the short-cut nitrification and denitrification reactor tower 2 is maintained at 6000 mg / L.

[0060] Example 4

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

[0062] S2-1, pre-starting of the short-cut nitrification and denitrification reactor tower 2: the NH4 + -N concentration of the initial ammonia-nitrogen-containing wastewater in the influent tank 1 is 400 mg / L, the COD concentration is 500 mg / L, the NO2 - -N concentration is 5 mg / L, the NO3 - -N concentration is 7 mg / L, the ammonia-nitrogen-containing wastewater in the influent tank 1 is pumped into the short-cut nitrification and denitrification reactor tower 2, the nitrification and denitrification treatment is performed in the short-cut nitrification and denitrification reactor tower 2, the ammonia-nitrogen-containing wastewater treated at the effluent end of the top of the short-cut nitrification and denitrification reactor tower 2 is backflowed to the influent end of the bottom of the short-cut nitrification and denitrification reactor tower 2, and the pollutant concentration inside the short-cut nitrification and denitrification reactor tower 2 is detected in real time, when the NO2 - -N: NH4 + -N is 1:1, and the NO2 - -N accumulation rate is 96%, the pre-starting of the short-cut nitrification and denitrification reactor tower 2 is successful;

[0063] S2-2, continuous treatment: aeration is carried out inside the short-cut nitrification and denitrification reaction tower 2, the aeration mode adopts micro-aerobic aeration, the dissolved oxygen is controlled at 0.3 mg / L, the sludge retention time is 25 d, the hydraulic retention time is 70 h, the discharge reflux ratio of the first reflux pump is controlled at 500%, the discharge reflux ratio of the sludge reflux pump is controlled at 100%, the ammonia-nitrogen-containing wastewater treated at the top water outlet end of the short-cut nitrification and denitrification reaction tower 2 is pumped into the sedimentation tank 3, after the completion of the sludge-water separation, the reused sludge and wastewater are obtained, the reused sludge is reinjected into the short-cut nitrification and denitrification reaction tower 2, and the wastewater is pumped into the intermediate water tank 4. Acid and alkali liquid are added into the intermediate water tank 4 to adjust the pH of the wastewater to 7.5, and the acid and alkali liquid is hydrochloric acid solution or sodium hydroxide solution.

[0064] Example 5

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

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

[0067] S2-2, continuous treatment: aeration is carried out inside the short-cut nitrification and denitrification reaction tower 2, the aeration mode adopts micro-aerobic aeration, the dissolved oxygen is controlled at 1.5 mg / L, the sludge retention time is 30 d, the hydraulic retention time is 72 h, the discharge reflux ratio of the first reflux pump is controlled at 500%, the discharge reflux ratio of the sludge reflux pump is controlled at 100%, the ammonia-nitrogen-containing wastewater treated at the top water outlet end of the short-cut nitrification and denitrification reaction tower 2 is pumped into the sedimentation tank 3, after the completion of the sludge-water separation, the reused sludge and wastewater are obtained, the reused sludge is reinjected into the short-cut nitrification and denitrification reaction tower 2, and the wastewater is pumped into the intermediate water tank 4. Acid and alkali liquid are added into the intermediate water tank 4 to adjust the pH of the wastewater to 8, and the acid and alkali liquid 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 ammonia oxidation sludge inoculation: the anaerobic ammonia oxidation granular sludge is dispersed into flocculent biomass for use, the water content of the anaerobic ammonia oxidation granular sludge is 90%, the VSS / TSS is 0.8, and the average diameter of the flocculent biomass is 90 μm. An equal volume of polyvinyl alcohol solution and sodium alginate solution is mixed uniformly to prepare a PVA-SA immobilization support solution, the mass concentration of the polyvinyl alcohol solution is 6%, and the mass concentration of the sodium alginate solution is 2%. Then, the PVA-SA immobilization support solution is sterilized in an autoclave at a temperature of 120°C for 30 min, and cooled to room temperature for use. The flocculent biomass is slowly added into the PVA-SA immobilization support solution, and biochar, which is corn straw biochar, is added at the same time. The mass ratio of the PVA-SA immobilization support solution, the flocculent biomass and the biochar is 7:1:8. After being mixed uniformly, the obtained mixture is dispersed and dripped into a plurality of polyurethane sponge blocks. Then, the polyurethane sponge blocks are placed in the cell immobilized anaerobic ammonia oxidation reactor 5. The anaerobic ammonia oxidation granular sludge concentration in the cell immobilized anaerobic ammonia oxidation reactor 5 is 6000 mg / L.

[0071] The polyurethane sponge blocks are arranged in a square structure with a side length of 1.5 cm. After the mixture is dispersed and dripped into a plurality of polyurethane sponge blocks, all the polyurethane sponge blocks are intensively fixed. The filling volume ratio of all the polyurethane sponge blocks in the cell immobilized anaerobic ammonia oxidation reactor 5 is 30%.

[0072] Embodiment 7

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

[0074] S3, cell immobilized anaerobic ammonia oxidation sludge inoculation: the anaerobic ammonia oxidation granular sludge is dispersed into flocculent biomass for use, the water content of the anaerobic ammonia oxidation granular sludge is 93%, the VSS / TSS is 1, the average diameter of the flocculent biomass is 95μm, an equal volume of polyvinyl alcohol solution and sodium alginate solution is mixed uniformly to prepare a PVA-SA immobilized support solution, the mass concentration of the polyvinyl alcohol solution is 6%, the mass concentration of the sodium alginate solution is 2%, then the PVA-SA immobilized support solution is sterilized in an autoclave at a temperature of 130℃ for 40min, and cooled to room temperature for use, the room temperature is 28℃, the flocculent biomass is slowly added into the PVA-SA immobilized support solution, and biochar is added at the same time, the mass ratio of the PVA-SA immobilized support solution, the flocculent biomass and the biochar is 9:1:10, after being mixed uniformly, the obtained mixture is dispersed and dripped into a plurality of polyurethane sponge blocks, then the polyurethane sponge blocks are placed in the cell immobilized anaerobic ammonia oxidation reactor 5, and the anaerobic ammonia oxidation granular sludge concentration in the cell immobilized anaerobic ammonia oxidation reactor 5 is 20000mg / L;

[0075] The polyurethane sponge blocks are arranged in a cube structure with a side length of 3cm, after the mixture is dispersed and dripped into a plurality of polyurethane sponge blocks, all the polyurethane sponge blocks are intensively fixed, and the filling volume ratio of all the polyurethane sponge blocks in the cell immobilized anaerobic ammonia oxidation reactor 5 is 70%.

[0076] Note: when the pollutant concentration in the treated wastewater is high, the anaerobic ammonia oxidation granular sludge concentration in the cell immobilized anaerobic ammonia oxidation reactor 5 should be appropriately increased, and the size of the polyurethane sponge block should also be appropriately increased, and the volume ratio of the polyurethane sponge block should also be increased.

[0077] Example 8

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

[0079] During intensive fixing, all the polyurethane sponge blocks are divided into two parts, one part is intensively fixed by deep cooling, and the other part is intensively fixed by general method, the ratio of the deep cooling intensively fixed polyurethane sponge block 7 to the general intensively fixed polyurethane sponge block 8 is 3:7, the deep cooling intensive fixing is liquid nitrogen quenching treatment of the polyurethane sponge block, the treatment time is 15min, the general intensive fixing is soaking the polyurethane sponge block in a CaCl2 solution with a mass concentration of 4% and fixing at 4℃ for 12h, during filling, the polyurethane sponge block intensively fixed by deep cooling is placed on the outside, and the polyurethane sponge block intensively fixed by general method is placed on the inside of the polyurethane sponge block intensively fixed by deep cooling.

[0080] Example 9

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

[0082] When the reinforcing fixation is performed, all the polyurethane sponge blocks are divided into two parts, one of which is subjected to deep cold reinforcing fixation, and the other is subjected to general reinforcing fixation, and the ratio of the deep cold reinforcing fixation polyurethane sponge block 7 to the general reinforcing fixation polyurethane sponge block 8 is 3:7. The deep cold reinforcing fixation is performed by subjecting the polyurethane sponge block to liquid nitrogen quenching treatment for 30 min. The general reinforcing fixation is performed by immersing the polyurethane sponge block in a CaCl2 solution with a mass concentration of 4% and fixing it at 4°C for 12 h. When the filling is performed, the polyurethane sponge block subjected to the deep cold reinforcing fixation is placed at the outside, and the polyurethane sponge block subjected to the general reinforcing fixation is placed at the inside of the polyurethane sponge block subjected to the deep cold reinforcing fixation.

[0083] Example 10

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

[0085] S4-1, Pre-starting of the cell-immobilized anaerobic ammonia oxidation reactor 5: the wastewater in the intermediate water tank 4 is pumped into the cell-immobilized anaerobic ammonia oxidation reactor 5, reaction is performed in the cell-immobilized anaerobic ammonia oxidation reactor 5, and the treated wastewater at the outlet is backflowed to the inlet at the bottom of the cell-immobilized anaerobic ammonia oxidation reactor 5. When the total nitrogen of the treated wastewater at the outlet is 65 mg / L, the pre-starting of the cell-immobilized anaerobic ammonia oxidation reactor 5 is successful.

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

[0087] Example 11

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

[0089] S4-1, Pre-starting of the cell-immobilized anaerobic ammonia oxidation reactor 5: the wastewater in the intermediate water tank 4 is pumped into the cell-immobilized anaerobic ammonia oxidation reactor 5, reaction is performed in the cell-immobilized anaerobic ammonia oxidation reactor 5, and the treated wastewater at the outlet is backflowed to the inlet at the bottom of the cell-immobilized anaerobic ammonia oxidation reactor 5. When the total nitrogen of the treated wastewater at the outlet is 68 mg / L, the pre-starting of the cell-immobilized anaerobic ammonia oxidation reactor 5 is successful.

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

[0091] Example 12

[0092] The present embodiment is an application of the method of treating biogas slurry by short-range nitrification-denitrification combined with cell immobilization anaerobic ammonia oxidation in Example 1, which is applied to efficient and low-power nitrogen removal treatment of biogas slurry in a pig farm.

[0093] Experimental Example 1

[0094] The method for treating ammonia-nitrogen-containing wastewater in Example 1 was used, and after the reactor assembly was stably operated, the COD concentration in the final effluent of the process section was 400-450 mg / L, the NH4 + -N concentration was less than 15 mg / L, the NO2 - -N concentration was less than 15 mg / L, the NO3 - -N concentration was less than 40 mg / L, the total nitrogen concentration was less than 70 mg / L, and the remaining COD was difficult-to-biodegrade organic matter, which needed subsequent physical and chemical means for removal, and the wastewater denitrification goal was achieved.

[0095] The nitrification reaction consumes alkalinity, which will cause the pH to decrease; while the denitrification and anaerobic ammonia oxidation process ANAMMOX is an alkalinity-producing reaction, which will cause the pH to increase. In addition, the increase in ARE can be attributed to the nitrification reaction and the ANAMMOX reaction; the increase in NRE can be attributed to the denitrification reaction and the ANAMMOX reaction.

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

[0097] In addition, we also compared Example 1 with the reactor without adding biochar as Comparative Example 2, and observed that the NH4 + -N and NO2 - -N concentrations in the reactor without adding biochar increased significantly slower than those in the reactor of Example 1, which indicated that the additional addition of biochar in the cell immobilization process was beneficial to improving the resistance of AnAOB to related inhibitory factors in the biogas slurry of a pig farm.

[0098] As Figure 3As shown, we also studied the relative abundance of different microorganisms at the door level. The main dominant phylum of the four sludge samples obtained is Chloroflexi, Proteobacteria and Bacteroidota, the sum of the abundance of the three is between 59.39% and 68.79%, and the relative abundance of Planctomycetota related to AnAOB in the inoculated sludge and the reactor is about 2%.

[0099] Proteobacteria and Chloroflexi usually coexist with Planctomycetota in the cell immobilized anaerobic ammonia oxidation reactor 5, they can utilize the nitrite and nitrate present in the reactor to consume the organic matter produced by microbial growth and metabolism, 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 the granulation of sludge and stable granular sludge. And studies have shown that many nitrifying and denitrifying bacteria belong to Proteobacteria and Bacteroidota. Therefore, the high proportion of these three phyla in the cell immobilized anaerobic ammonia oxidation reactor 5 explains the occurrence of nitrification and denitrification in each reactor.

[0100] Experimental example 2

[0101] According to the method in example 1, the ammonia nitrogen-containing wastewater treatment is carried out, and compared with comparative example 3, the difference between comparative example 3 and example 1 is that all the polyurethane sponge blocks are generally strengthened and fixed;

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

[0103] Table 1 NRR comparison of example 1 and comparative example 3

[0104]

[0105] It can be found that under the same NLR conditions, the NRR of the two reactors decreases significantly, and the denitrification performance of the reactor begins to deteriorate, indicating that real wastewater can cause more intense inhibition of AnAOB, and AnAOB activity appears a serious decline. In actual wastewater, there are substances that inhibit AnAOB, while the slow release of AnAOB in example 1 can effectively alleviate this problem, and the NRR can still remain at a high level in the later treatment period, while in comparative example 3, there is a larger decrease. Therefore, the use of the strengthening and fixing method in example 1 will be more helpful to realize the engineering application of ANAMMOX technology in pig farm biogas slurry denitrification treatment.

Claims

1. A method for treating biogas slurry by short-cut nitrification and denitrification combined with cell-immobilized anaerobic ammonia oxidation, wherein the biogas slurry is guided to a short-cut nitrification and denitrification reactor (2) from a water inlet tank (1), the biogas slurry is treated by nitrification and denitrification in the short-cut nitrification and denitrification reactor (2), the treated biogas slurry is precipitated in a sedimentation tank (3), the biogas slurry is guided from an intermediate water tank (4), and the biogas slurry is treated by cell-immobilized anaerobic ammonia oxidation in a cell-immobilized anaerobic ammonia oxidation reactor (5), and finally the treated biogas slurry is discharged from a water outlet tank (6). characterized in that The nitration denitrification process needs to control the NO2 - -N and NH4 + The ratio of -N is 1-1.5:1, and NO2 - -N accumulation rate > 95%; The method comprises the following steps: S1, short-cut nitrification and denitrification sludge inoculation: inoculating aerobic sludge from a sewage plant into the short-cut nitrification and denitrification reactor (2) to maintain the concentration of the aerobic sludge in the short-cut nitrification and denitrification reactor (2) at 3000-6000 mg / L; S2, nitrification and denitrification treatment: S2-1, Pre-start of Short-range Nitrification and Denitrification Reactor (2): Pump the biogas slurry into the Short-range Nitrification and Denitrification Reactor (2), and return all the biogas slurry at the outlet end, and detect the pollutant concentration in real time. When the NO2 - -N: NH4 + -N is 1~1.5:1, 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: aerating the short-cut nitrification and denitrification reactor (2) and continuously pumping the biogas slurry into the reactor, the treated biogas slurry is pumped into the sedimentation tank (3), and the biogas slurry is treated by cell-immobilized anaerobic ammonia oxidation in the cell-immobilized anaerobic ammonia oxidation reactor (5) after the separation of the sludge and water; The cell-immobilized anaerobic ammonia oxidation treatment requires the sludge in the cell-immobilized anaerobic ammonia oxidation reactor (5) to be strengthened inoculation: S3, cell-immobilized anaerobic ammonia oxidation sludge strengthening inoculation: dispersing anaerobic ammonia oxidation granular sludge into flocculent biomass, mixing equal volumes of polyvinyl alcohol solution and sodium alginate solution to prepare PVA-SA immobilized support solution, sterilizing the PVA-SA immobilized support solution at high temperature and cooling it to room temperature, adding the flocculent biomass and biochar, the mass ratio of the PVA-SA immobilized support solution, the flocculent biomass and the biochar being 7-9:1:8-10, mixing them uniformly, and dropping the mixture into several polyurethane sponge blocks, placing the polyurethane sponge blocks in the cell-immobilized anaerobic ammonia oxidation reactor (5), and the concentration of the anaerobic ammonia oxidation granular sludge in the cell-immobilized anaerobic ammonia oxidation reactor (5) being 6000-20000 mg / L; The polyurethane sponge blocks in S3 are cubes with a side length of 1.5-3 cm, the mixture is dispersed and dropped into several polyurethane sponge blocks, and all the polyurethane sponge blocks are strengthened and fixed, the filling volume of all the polyurethane sponge blocks in the cell-immobilized anaerobic ammonia oxidation reactor (5) accounting for 30-70%; In the strengthening and fixing, all the polyurethane sponge blocks are divided into two parts, one part is subjected to cryogenic strengthening and fixing, and the other part is subjected to general strengthening and fixing, the ratio of the obtained cryogenic strengthening and fixing polyurethane sponge blocks (7) to the general strengthening and fixing polyurethane sponge blocks (8) being 3:7, the cryogenic strengthening and fixing is liquid nitrogen quenching treatment of the polyurethane sponge blocks, the treatment time being 15-30 min, and the general strengthening and fixing is soaking the polyurethane sponge blocks in a CaCl2 solution with a mass concentration of 4% and fixing them at 4℃ for 12 h, in the filling, the polyurethane sponge blocks subjected to cryogenic strengthening and fixing are placed on the outside, and the polyurethane sponge blocks subjected to general strengthening and fixing are placed on the inside of the polyurethane sponge blocks subjected to cryogenic strengthening and fixing. S4, cell immobilization anaerobic ammonia oxidation treatment: S4-1, pre-starting of cell immobilization anaerobic ammonia oxidation reactor (5): pumping biogas slurry into the cell immobilization anaerobic ammonia oxidation reactor (5), and returning all the effluent biogas slurry, and detecting the pollutant concentration in real time, when the total nitrogen of the treated wastewater at the effluent end is less than 70 mg / L, the pre-starting of the cell immobilization anaerobic ammonia oxidation reactor (5) is successful; S4-2, continuous treatment: continuously pumping biogas slurry, the hydraulic retention time of the wastewater in the cell immobilization anaerobic ammonia oxidation reactor (5) is 16-18 h, the upflow velocity is 3-5 m / h, and finally the effluent is discharged through the effluent water tank (6).

2. The process for the short-cut nitrification-denitrification combined cell immobilized anaerobic ammonia oxidation treatment of biogas slurry according to claim 1, characterized in that, The S2-1 adjusts the NH4 + -N concentration is 400-1600 mg / L, COD concentration is 500-3500 mg / L, NO2 - -N concentration is 0-30 mg / L, NO3 - -N concentration is 0-30 mg / L.

3. The process for the short-cut nitrification-denitrification combined cell immobilized anaerobic ammonia oxidation treatment of biogas slurry according to claim 1, characterized in that, The aeration mode in S2-2 is micro-aerobic aeration, and the dissolved oxygen in the short-cut nitrification and denitrification reactor (2) is controlled at 0.3-1.5 mg / L when aeration is performed, the sludge retention time is 25-30 d, the hydraulic retention time is 70-72 h, the discharge reflux ratio is controlled at 500%, the discharge reflux ratio of the recycled sludge obtained by the separation of sludge and water in the sedimentation tank (3) is 100%, the recycled sludge is injected into the short-cut nitrification and denitrification reactor (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, and the acid and alkali solution is hydrochloric acid solution or sodium hydroxide solution.

4. The process for the short-cut nitrification-denitrification combined cell-immobilized anaerobic ammonium oxidation treatment of biogas slurry according to claim 1, characterized in that, The moisture content of the anaerobic ammonia 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.

5. The process for the short-cut nitrification-denitrification combined cell-immobilized anaerobic ammonium oxidation treatment of biogas slurry according to claim 1, 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℃, the sterilization time is 30-40 min, and the normal temperature is 25-28℃.

6. The process for the short-cut nitrification-denitrification combined cell-immobilized anaerobic ammonium oxidation treatment of biogas slurry according to claim 1, characterized in that, The biochar in S3 is corn straw biochar.

7. Use of the process for the treatment of biogas effluents by short-cut nitrification-denitrification combined cell immobilized anaerobic ammonium oxidation according to claim 1, characterized in that, The method is applied to the denitrification treatment of biogas slurry in a pig farm.

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