AAO (anaerobic ammonia oxidation) sewage treatment method capable of performing anaerobic ammonia oxidation denitrification

Abstract

The invention discloses an AAO (anaerobic ammonia oxidation) sewage treatment method capable of carrying out anaerobic ammonia oxidation denitrification, which comprises the following steps of: adding fillers for microorganisms to adhere to in an anaerobic tank and an anoxic tank in AAO treatment, and enriching anaerobic ammonia oxidation bacteria in the anaerobic tank and the anoxic tank by virtue of an enrichment means, so that the quantity of the anaerobic ammonia oxidation bacteria is dominant in flora; anaerobic ammoxidation biochemical reaction is realized in the anaerobic tank and the anoxic tank, and nitrogen is converted into nitrogen. According to the method provided by the invention, after the wastewater passes through the anaerobic tank and the anoxic tank, the accumulated removal rate of NH3-N reaches 89.5%, and the accumulated removal rate of TN reaches 89.3%; the power consumption is saved by 60%, the carbon source is saved by 100%, and energy conservation and consumption reduction in the sewage treatment process are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of AAO sewage treatment and relates to an AAO sewage treatment method capable of performing anaerobic ammonia oxidation denitrification. Background Art

[0002] The traditional nitrification and denitrification process requires the NH4 + Oxidation into NO2 by nitrosating bacteria - , and then oxidized into NO3 by nitrifying bacteria - It is the nitrification process; and NO3 - The denitrification process is to use denitrifying bacteria to generate N2 through denitrification. Anaerobic ammonium oxidizing bacteria is an autotrophic, obligate anaerobe belonging to Brocadiales of the phylum Planctomycetes, with a total of 6 genera and 27 species. Most anaerobic ammonium oxidizing bacteria are cocci with a diameter of 800-1100nm, and the cells are generally red. The reproduction method of anaerobic ammonium oxidizing bacteria is binary fission, but the growth of anaerobic ammonium oxidizing bacteria in existing treatment pools is very slow. Summary of the invention

[0003] The technical problem solved by the present invention is to provide an AAO sewage treatment method capable of carrying out anaerobic ammonia oxidation denitrification, wherein anaerobic ammonia oxidation reaction is achieved in the anaerobic zone and the anoxic zone by transforming the anaerobic tank and the anoxic tank.

[0004] The present invention is achieved through the following technical solutions:

[0005] An AAO wastewater treatment method capable of anaerobic ammonium oxidation denitrification is to add fillers for microorganisms to attach to the anaerobic tank and anoxic tank in the AAO treatment, and then enrich the anaerobic ammonium oxidizing bacteria in the anaerobic tank and anoxic tank by enrichment means, so that the number of anaerobic ammonium oxidizing bacteria is dominant in the bacterial community, and the anaerobic ammonium oxidation biochemical reaction is realized in the anaerobic tank and the anoxic tank to convert NH4 + Converted to nitrogen.

[0006] Further, the filler comprises:

[0007] A fixed frame is arranged in the anaerobic tank, and a filler rope for microorganisms to attach to is fixed on the fixed frame;

[0008] Suspended fillers are placed in the anoxic tank to which microorganisms can attach.

[0009] Furthermore, the anaerobic pool is divided into several independent treatment pools, the water inlet mode of each treatment pool is changed to bottom-in and top-out, and a water outlet weir is set at the water outlet;

[0010] The anaerobic tank is divided into several interconnected parts.

[0011] Furthermore, the amount of filler used in the anaerobic tank is 50-60% of the tank capacity;

[0012] Fixed frames are respectively arranged on the top and bottom of the anaerobic tank, which serve as upper and lower fixing points of the packing ropes, and the packing ropes are arranged in parallel along the vertical direction of the anaerobic tank.

[0013] Furthermore, the thickness of the microorganisms attached to the filler rope is 400nm-600nm, wherein the outermost layer is attached with anaerobic bacteria, and the innermost layer is attached with anaerobic ammonia-oxidizing bacteria.

[0014] Furthermore, the size of the water outlet weir is 600mm in width and 600mm in height, and the length of the water outlet weir is consistent with the width of the pool; the position of the water outlet weir is 500mm below the top of the pool.

[0015] Furthermore, the amount of suspended filler used in the anoxic pool is 40-50% of the pool capacity;

[0016] The material of the suspended filler is HDPE, and porous channels are provided on the suspended filler.

[0017] Further, the enrichment means comprises:

[0018] 1) Increase the concentration of mixed liquid sludge in the anaerobic tank and anoxic tank to 4500-5500 mg / L; at the same time, increase the dosage of phosphorus removal agent to 40-50 mg / L;

[0019] While increasing the sludge concentration, the sludge age is increased to 20-25 days, so that the absolute number of anaerobic ammonia-oxidizing bacteria gradually increases;

[0020] 2) Control of dissolved oxygen: The dissolved oxygen in the anaerobic tank is controlled to be less than 0.2mg / L, the dissolved oxygen in the anoxic tank is controlled to be less than 0.3mg / L, the dissolved oxygen in the aerobic tank is controlled to be 0.2-0.5mg / L, and the dissolved oxygen at the outlet of the aerobic tank is controlled to be between 0.3-0.5mg / L;

[0021] 3) Maintain the COD of anaerobic tank at 30-40mg / L and the COD of anoxic tank at 20-30mg / L;

[0022] 4) Reflux ratio control: adopt two-stage reflux, the external reflux ratio is controlled at 60%, and the internal reflux ratio is controlled at 200%.

[0023] Furthermore, the sludge concentration is monitored by the sludge concentration monitor. When the sludge concentration is high, the residual sludge pump in the sludge pump room of the secondary sedimentation tank is turned on to discharge part of the sludge into the sludge thickening tank for treatment. If the sludge concentration is too low, the sludge discharge is reduced and the sludge concentration will gradually increase.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] The AAO sewage treatment method for anaerobic ammonia oxidation denitrification provided by the present invention can make anaerobic ammonia oxidizing bacteria adhere to the filler to grow, reproduce and enrich by transforming the anaerobic tank and the anoxic tank, so that the anaerobic ammonia oxidizing bacteria become the dominant bacterial group, so that the anaerobic ammonia oxidation biochemical reaction can be realized in the anaerobic tank and the anoxic tank; using NH4 + Provide electrons, nitrite nitrogen is the electron acceptor, and NH4 + Converted into nitrogen; Intersect with existing treatment process, eliminating the need for NH4 + Oxidized to NO3 - The process achieves a significant reduction in electricity and carbon source consumption.

[0026] The AAO sewage treatment method capable of performing anaerobic ammonia oxidation denitrification provided by the present invention comprises the following steps: the anaerobic pool is divided into three independent pools, each of which adopts a bottom-in-top-out method, and biological fillers are added to the anaerobic pool and the anoxic pool to create a suitable growth environment for the anaerobic ammonia oxidizing bacteria, and then the anaerobic ammonia oxidizing bacteria are attached; the anaerobic ammonia oxidizing bacteria can be enriched by using the sludge in the existing sewage treatment system to achieve a sewage biochemical system in which the number of its microorganisms gradually dominates, thereby changing the original sewage treatment path and saving organic carbon sources and electricity consumption; the cumulative removal rate of NH3-N of the wastewater after passing through the anaerobic pool and the anoxic pool reaches 89.5%, and the cumulative removal rate of TN reaches 89.3%; compared with the traditional nitrification / denitrification denitrification process, the anaerobic ammonia oxidation can reduce the dosage of the organic carbon source by 100%, and the electricity consumption by 60%, thereby realizing energy saving and consumption reduction in the sewage treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the AAO sewage treatment tank of the present invention;

[0028] Figure 2 It is one of the cross-sectional schematic diagrams of the anaerobic tank of the present invention;

[0029] Figure 3 This is the second schematic cross-sectional view of the anaerobic tank of the present invention; wherein 1 is the outlet weir, and 2 is the filler rope;

[0030] Figure 4 It is a schematic diagram comparing the anaerobic ammonium oxidation reaction mechanism of the present invention with the mechanism of the traditional biological denitrification process;

[0031] Figure 5 It is a schematic diagram of fixed filler in anaerobic tank;

[0032] Figure 6 It is a schematic diagram of the suspended filler in the anoxic tank;

[0033] Figure 7 This is the COD value change diagram of each AAO treatment unit;

[0034] Figure 8 This is the TN value change diagram of each processing unit of AAO;

[0035] Fig. 9 This is the NH3-N value change diagram of each AAO treatment unit;

[0036] Fig.10 NO3 for each AAO processing unit - Numerical change graph;

[0037] Fig.11 NO2 for each AAO processing unit - Numerical change graph;

[0038] Fig.12 This is the TP value change diagram of each processing unit of AAO;

[0039] Fig.13 This is the DO value change diagram of each processing unit of AAO;

[0040] Fig.14 This is the MLSS value change diagram of each AAO processing unit. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with the embodiments, which are intended to explain the present invention rather than to limit it.

[0042] An AAO sewage treatment method for anaerobic ammonium oxidation denitrification is to add fillers for microorganism attachment to the anaerobic tank and anoxic tank in the AAO treatment (for example, Figure 1 Then, the anaerobic ammonium oxidizing bacteria are enriched in the anaerobic tank and the anoxic tank by enrichment means, so that the number of anaerobic ammonium oxidizing bacteria is dominant in the bacterial community, and the anaerobic ammonium oxidation biochemical reaction is realized in the anaerobic tank and the anoxic tank to convert NH4 + Converted to nitrogen.

[0043] See also Figure 1-Figure 3 , the additional fillers include:

[0044] A fixed frame is arranged in the anaerobic tank, and a filler rope for microorganisms to attach to is fixed on the fixed frame;

[0045] Suspended fillers are placed in the anoxic tank to which microorganisms can attach.

[0046] For further information, see Figure 1 , the anaerobic pool is divided into several independent treatment pools, the water inlet mode of each treatment pool is changed to bottom-in and top-out, and a water outlet weir is set at the outlet;

[0047] The anaerobic tank is divided into several interconnected parts.

[0048] See also Figure 4 , existing NH4 + Using nitrite bacteria to convert into NO2 - , NO2 - It is converted into NO3 by nitrifying bacteria - , NO3 - It is converted into N2 by denitrifying bacteria; during the denitrifying bacteria reaction, a carbon source is needed to provide electrons to reduce nitrate nitrogen to nitrogen gas. Therefore, many sewage treatment plants need to add a carbon source to complete the denitrification process. In addition, the addition of a carbon source will also lead to an increase in the amount of residual sludge.

[0049] The biochemical reaction of the present invention is based on nitrite nitrogen (NO2 - ) as electron acceptor, directly converting NH4 + Oxidized into nitrogen, eliminating NO2 in the reaction process - Oxidized to NO3 - The reaction equation of the process is:

[0050] NH4 + +1.32NO2 - +0.066HCO3 - +0.13H + →1.02N2

[0051] In addition, due to NH4 + As an electron donor, there is no need to add additional carbon source, which saves carbon source costs and electricity.

[0052] The filler is further described below.

[0053] Specifically, the amount of filler used in the anaerobic tank is 50-60% of the tank capacity;

[0054] Fixed frames are respectively arranged on the top and bottom of the anaerobic tank, which serve as upper and lower fixing points of the packing ropes, and the packing ropes are arranged in parallel along the vertical direction of the anaerobic tank.

[0055] Specific filler rope such as Figure 5 As shown, a single layer of steel mesh is laid as the upper and lower fixing points of the filler rope, and the filler rope is tied to the upper and lower steel bars.

[0056] The thickness of microorganisms attached to the filler rope is 400nm-600nm, with anaerobic bacteria attached to the outermost layer and anaerobic ammonium-oxidizing bacteria attached to the innermost layer. Anaerobic bacteria degrade organic matter in sewage to produce carbon dioxide and water, while anaerobic ammonium-oxidizing bacteria use carbon dioxide as a carbon source, nitrite as an oxidant, and ammonia as an electron donor to reduce nitrite to nitrogen.

[0057] The filler rope can be made of elastic three-dimensional material, which can make the sewage and biofilm fully mixed, contacted and exchanged. The biofilm can not only sit evenly on the silk strips in large quantities and maintain good activity, but also have a good metabolism and will not stick together.

[0058] Specifically, the outlet weir is made of carbon steel for corrosion resistance, with dimensions of 600mm in width and 600mm in height. The length of the outlet weir is consistent with the width of the pool. The top of the outlet weir is located 500mm below the top of the pool to adapt to changes in the water outlet method.

[0059] The amount of suspended filler used in the anoxic pool is 40-50% of the pool capacity;

[0060] The material of the suspended filler is HDPE, and porous channels are provided on the suspended filler. The shape of the channels is not limited, so that the attachment area of ​​microorganisms can be increased;

[0061] See also Figure 6 The suspended filler is made into a cylindrical shape with porous channels, the diameter of the plane circle is 20 to 25 mm, and the thickness of the column is 8 to 10 mm.

[0062] Specific examples are given below.

[0063] Example 1

[0064] The AAO sewage treatment pool was transformed as follows and anaerobic ammonia oxidizing bacteria were enriched:

[0065] (1) Adding fillers:

[0066] Add fillers to anaerobic and anoxic tanks to allow anaerobic ammonia-oxidizing bacteria to attach and grow on them;

[0067] Specifically, 60% of the volume of the anaerobic tank is filled with three-dimensional fillers, and 50% of the volume of the anoxic tank is filled with suspended fillers.

[0068] These fillers provide a good living carrier for anaerobic ammonium oxidizing bacteria, allowing them to be enriched on them; anaerobic ammonium oxidizing bacteria are domesticated and cultivated using activated sludge in the original sewage treatment system.

[0069] 2) Control of dissolved oxygen (DO):

[0070] The dissolved oxygen in the anaerobic tank is controlled to be less than 0.2mg / L, the dissolved oxygen in the anoxic tank is less than 0.3mg / L, and the dissolved oxygen in the aerobic tank is controlled to be less than 0.2mg / L. Figure 1 As shown, the aerobic pool is divided into aerobic pool 1, aerobic pool 2, and aerobic pool 3) the dissolved oxygen is controlled at 0.2-0.5 mg / L, and the dissolved oxygen at the outlet of the aerobic pool is controlled between 0.3-0.5 mg / L;

[0071] 3) Control of sludge concentration:

[0072] Reduce the discharge of excess sludge in the secondary sedimentation tank, increase the mixed liquor sludge concentration (MLSS) in the anaerobic tank and anoxic tank to 4500-5500 mg / L; at the same time, increase the dosage of phosphorus removal agent to 40-50 mg / L;

[0073] Specifically, the sludge concentration is monitored by the sludge concentration monitor. When the sludge concentration is high, the residual sludge pump in the sludge pump room of the secondary sedimentation tank is turned on to discharge part of the sludge into the sludge thickening tank for treatment; if the sludge concentration is too low, the sludge discharge is reduced and the sludge concentration will gradually increase;

[0074] 4) Maintain the COD of anaerobic tank at 30-40mg / L and the COD of anoxic tank at 20-30mg / L;

[0075] 5) Reflux ratio control: adopt two-stage reflux, the external reflux ratio is controlled at 60%, and the internal reflux ratio is controlled at 200%;

[0076] 6) Sludge age control: While increasing the sludge concentration, increase the sludge age to 20-25 days, so that the absolute number of anaerobic ammonia-oxidizing bacteria gradually increases.

[0077] During the renovation and commissioning process, in order to ensure that the water output indicators meet the standards, gradual adjustment steps were taken, as follows:

[0078] 1. Adjustment of sludge concentration

[0079] In the traditional operation process, the growth rate of anaerobic ammonium oxidizing bacteria is lower than that of nitrite oxidizing bacteria. The growth of nitrite oxidizing bacteria will cause most of the ammonia to be converted into NO3 - , rather than N2. Therefore, we took the approach of increasing sludge concentration and increasing sludge age, so that the absolute number of anaerobic ammonium oxidizing bacteria gradually increased. The increase in the number of anaerobic ammonium oxidizing bacteria enhanced its competitive advantage over nitrite oxidizing bacteria.

[0080] In the process of increasing the sludge concentration, the mixed liquor sludge concentration (MLSS) is increased to 5000 mg / L. The method adopted is to reduce the discharge of residual sludge from the secondary sedimentation tank. Since a large amount of fresh sewage enters the biochemical pool every day, the amount of microorganisms in the sewage continues to increase. If the residual sludge is not discharged, the sludge concentration in the biochemical pool will increase day by day.

[0081] In addition, attention should be paid to the changes in effluent indicators. The increase in sludge concentration will inevitably lead to a decrease in phosphorus removal effect. Therefore, it is necessary to continuously increase the dosage of phosphorus removal agent. The dosage of phosphorus removal agent is increased from 25mg / L to 50mg / L.

[0082] 2. DO (dissolved oxygen) control

[0083] The existing AAO process controls the dissolved oxygen in the aerobic pool at 2-4 mg / L, which makes it difficult to cultivate anaerobic ammonium oxidizing bacteria. The invention's method is to first reduce the dissolved oxygen concentration to artificially create a production environment for anaerobic ammonium oxidizing bacteria.

[0084] Anaerobic ammonium oxidizing bacteria are strictly anaerobic microorganisms and can only survive in an environment with an oxygen partial pressure of less than 5%. Once the oxygen partial pressure exceeds 18%, the activity of anaerobic ammonium oxidizing bacteria is inhibited. However, this inhibition is reversible. Another reason is that when DO is low, the activity of nitrifying bacteria is weaker than that of anaerobic ammonium oxidizing bacteria. In an environment with a dissolved oxygen of about 0.5 mg / L, anaerobic ammonium oxidizing bacteria are highly active, suitable for growth and reproduction, and degrade ammonia nitrogen in the water body. The general biological nitrification reaction requires the dissolved oxygen to be controlled at 2-4 mg / L. Therefore, the aeration valve can be adjusted repeatedly, and on the premise of ensuring that the ammonia nitrogen in the effluent meets the standard, the dissolved oxygen concentration returned to the anaerobic tank can be continuously tried to provide an environment suitable for the growth of anaerobic ammonium oxidizing bacteria, allowing them to continue to reproduce and eventually reach a certain number, and the anaerobic ammonium oxidizing bacteria can be cultivated into a dominant bacterial community.

[0085] Specifically, adjust the aeration valve of the biochemical pool and reduce the aeration volume of the valve of the aerobic pool 1 to ensure that the dissolved oxygen is controlled at 0.2-0.5 mg / L;

[0086] Adjust the valve of aerobic pool 2 to control the dissolved oxygen to 0.3-0.5 mg / L;

[0087] Control the air supply valve of aerobic pool 3 to ensure that the dissolved oxygen at the dissolved oxygen outlet is controlled at 0.3-0.5 mg / L.

[0088] During the adjustment of the aeration valve, pay attention to the changes in effluent ammonia nitrogen. If the effluent ammonia nitrogen increases, the aeration valve needs to be adjusted back and forth, especially the valve of the aerobic pool 3, which needs to be adjusted back and forth many times. The repeated adjustment of the aeration valve is also a gradual cultivation process of anaerobic ammonia-oxidizing bacteria.

[0089] However, during the commissioning process, we also need to ensure that the ammonia nitrogen in the effluent of the sewage treatment plant meets the standard. Therefore, we need to constantly adjust the aeration, and under the bottom line of ensuring that the ammonia nitrogen in the effluent meets the standard, continuously reduce the dissolved oxygen in the biochemical pool to the design range to meet its living environment.

[0090] 3. Control of organic matter concentration in wastewater

[0091] During the anaerobic ammonium oxidation process, the carbon in the influent needs to be reduced to a lower level. The presence of higher carbon promotes the growth of heterotrophic bacteria. The method adopted is to reduce the sludge BOD load by increasing the sludge concentration. Because the wastewater enters the anaerobic tank, when there is a high concentration of sludge, a large amount of carbon source is first adsorbed on the sludge. Under anaerobic conditions, the organic matter in the wastewater is converted into acetic acid by acid-producing bacteria, and the polyphosphate bacteria immediately absorbs acetic acid and H + and electrons, forming PHB which is stored in the cells of polyphosphate bacteria. Under aerobic conditions, polyphosphate bacteria decompose PHB to release energy, part of which is used for its own reproduction and the other part is used for the absorption of inorganic phosphorus, forming polyphosphates which are stored in the cells.

[0092] Therefore, by regulating the high sludge concentration, keeping the COD in the anaerobic area at 30-40 mg / L and the COD in the anoxic area at 20-30 mg / L, suitable conditions for the cultivation of anaerobic ammonia-oxidizing bacteria can be created.

[0093] 4. Control of internal reflux ratio

[0094] The present invention adopts 200% internal circulation, which has the following functions: first, diluting the incoming water, reducing the impact load, and creating a stable growth environment for microorganisms; second, uniformizing the pollution load in the system and making the dissolved oxygen control stable.

[0095] 5. Control of external reflux ratio

[0096] The external reflux rate was controlled at 60%.

[0097] 6. Control of mud age

[0098] The sludge age is controlled at 20-25 days.

[0099] After the AAO sewage treatment pool capable of anaerobic ammonia oxidation denitrification was adjusted, the data of each treatment unit changed for three consecutive days. Figure 7-Figure 14 shown.

[0100] 1. Numerical analysis of pollutants in anaerobic tanks

[0101] 1. Anaerobic pool raw water flow 300m 3 / h, the external return pump returns 60% of the influent water, and the external return flow of the secondary sedimentation tank sludge is 180m 3 / h;

[0102] 2. The nitration liquid reflux volume is 600m 3 / h;

[0103] 3. Through the transformation, we installed fixed biological fillers in the anaerobic tank and suspended biological fillers in the anoxic tank. This transformation is conducive to the attachment and cultivation of anaerobic ammonium oxidizing bacteria, and accelerates the rapid start-up of the anaerobic ammonium oxidation process. Two months after the installation, the anaerobic ammonium oxidation process was able to operate normally, and the removal rate of pollutants in the effluent was also improved compared to the period before the fillers were installed.

[0104] 4. Anaerobic pool pollutant removal rate:

[0105] The average COD removal rate was 84.2%;

[0106] The average TN removal rate was 76.4%;

[0107] The average removal rate of NH3-N was 77.3%;

[0108] The reduction in COD is due to the fact that anaerobic bacteria convert organic matter into acetic acid, and then phosphorus-removing bacteria absorb acetic acid to produce PHB in the cells.

[0109] The lesser amount of total nitrogen and ammonia nitrogen is converted into N2 and released into the air through anaerobic ammonium oxidation.

[0110] 2. Numerical analysis of pollutants in anoxic pools

[0111] 1. The sewage flow rate from the anaerobic tank to the anoxic tank is 480m 3 / h;

[0112] The flow rate of nitrification liquid returning to the anoxic tank is 600m 3 / h;

[0113] 2. Pollutant removal rate in anoxic pool:

[0114] The average COD removal rate was 33%;

[0115] The average TN removal rate was 54%;

[0116] The average removal rate of NH3-N was 53%;

[0117] 3. The dissolved oxygen in the anoxic pool is less than 0.3 mg / L;

[0118] Through data analysis, the removal rates of TN and NH3-N are close to 50%, which is due to the conversion of 25% of ammonia nitrogen into nitrite nitrogen and the remaining 25% of NH3-N reacting to produce N2.

[0119] NH4 + +1.32NO2 - +0.066HCO3 - +0.13H + →1.02N2

[0120] Therefore, anaerobic ammonium oxidation reaction occurred in both the anaerobic tank and the anoxic tank. After the anaerobic tank and the anoxic tank, the total removal rate of NH3-N reached 89.5%, and the total removal rate of TN reached 89.3%, which was exactly consistent with the proportional consumption ratio of the anaerobic ammonium oxidation reaction formula.

[0121] After the debugging of the anaerobic ammonium oxidation process was completed, the nitrogen removal effect was obvious, the carbon source was saved by 100%, the power consumption was reduced by 60%, and the phosphorus removal agent was also reduced by 60% compared with the traditional process.

[0122] Power consumption: The original power consumption of the fan was 70kw·h. With the new process, the power consumption was reduced to 28kw·h, a 60% reduction.

[0123] Carbon source consumption: Originally, 125kg of carbon source was added every day. With the new process, no carbon source addition was performed, thus achieving energy saving and consumption reduction in the sewage treatment process.

[0124] The above embodiments are preferred examples for implementing the present invention, and the present invention is not limited to the above embodiments. Any non-essential additions and substitutions made by those skilled in the art based on the technical features of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for treating wastewater by anaerobic ammonium oxidation (AAO) denitrification, characterized in that: The anaerobic tank and anoxic tank in AAO sewage treatment are equipped with fillers for microorganisms to attach to, and then the anaerobic ammonium oxidizing bacteria are enriched in the anaerobic tank and anoxic tank by enrichment means, so that the number of anaerobic ammonium oxidizing bacteria is dominant in the bacterial community, and the anaerobic ammonium oxidation biochemical reaction is realized in the anaerobic tank and anoxic tank to convert NH4 + Converted to nitrogen.

2. The AAO wastewater treatment method capable of anaerobic ammonium oxidation denitrification according to claim 1, characterized in that: The filler comprises: A fixed frame is arranged in the anaerobic tank, and a filler rope for microorganisms to attach to is fixed on the fixed frame; Suspended fillers are placed in the anoxic tank to which microorganisms can attach.

3. The AAO sewage treatment method capable of anaerobic ammonium oxidation denitrification according to claim 2, characterized in that: The anaerobic pool is divided into several independent treatment pools, the water inlet mode of each treatment pool is changed to bottom-in and top-out, and a water outlet weir is set at the outlet; The anaerobic tank is divided into several interconnected parts.

4. The AAO sewage treatment method capable of anaerobic ammonium oxidation denitrification according to claim 2 or 3, characterized in that: The amount of filler used in the anaerobic tank is 50-60% of the tank capacity; Fixed frames are respectively arranged on the top and bottom of the anaerobic tank, which serve as upper and lower fixing points of the packing ropes, and the packing ropes are arranged in parallel along the vertical direction of the anaerobic tank.

5. The AAO sewage treatment method capable of anaerobic ammonium oxidation denitrification according to claim 4, characterized in that: The thickness of microorganisms attached to the filler rope is 400nm-600nm, of which the outermost layer is attached with anaerobic bacteria and the innermost layer is attached with anaerobic ammonia-oxidizing bacteria.

6. The AAO sewage treatment method capable of anaerobic ammonium oxidation denitrification according to claim 3, characterized in that: The size of the water outlet weir is 600mm in width and 600mm in height, and the length of the water outlet weir is consistent with the width of the pool; the position of the water outlet weir is 500mm below the top of the pool as the top of the water outlet weir.

7. The AAO sewage treatment method capable of anaerobic ammonium oxidation denitrification according to claim 2 or 3, characterized in that: The amount of suspended filler used in the anoxic pool is 40-50% of the pool capacity; The material of the suspended filler is HDPE, and porous channels are provided on the suspended filler.

8. The AAO wastewater treatment method capable of anaerobic ammonium oxidation denitrification according to claim 1, characterized in that: The enrichment means include: 1) Increase the concentration of mixed liquid sludge in the anaerobic tank and anoxic tank to 4500-5500 mg / L; at the same time, increase the dosage of phosphorus removal agent to 40-50 mg / L; While increasing the sludge concentration, the sludge age is increased to 20-25 days, so that the absolute number of anaerobic ammonia-oxidizing bacteria gradually increases; 2) Control of dissolved oxygen: The dissolved oxygen in the anaerobic tank is controlled to be less than 0.2mg / L, the dissolved oxygen in the anoxic tank is controlled to be less than 0.3mg / L, the dissolved oxygen in the aerobic tank is controlled to be 0.2-0.5mg / L, and the dissolved oxygen at the outlet of the aerobic tank is controlled to be between 0.3-0.5mg / L; 3) Maintain the COD of anaerobic tank at 30-40mg / L and the COD of anoxic tank at 20-30mg / L; 4) Reflux ratio control: adopt two-stage reflux, the external reflux ratio is controlled at 60%, and the internal reflux ratio is controlled at 200%.

9. The AAO wastewater treatment method capable of anaerobic ammonium oxidation denitrification according to claim 8, characterized in that: Monitor the sludge concentration using the sludge concentration monitor. When the sludge concentration is high, turn on the residual sludge pump in the sludge pump room of the secondary sedimentation tank to discharge part of the sludge into the sludge concentration tank for treatment. If the sludge concentration is too low, reduce sludge discharge and the sludge concentration will gradually increase.

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