AAO (anaerobic-anoxic-oxic) treatment device with filler

Abstract

The utility model discloses an AAO (anaerobic-anoxic-oxic) treatment device with fillers, which comprises an anaerobic tank, an anoxic tank and an aerobic tank, and the fillers for microorganisms to adhere are additionally arranged in the anaerobic tank and the anoxic tank; the filler comprises a fixed frame arranged in the anaerobic tank, and a filler rope for attachment of microorganisms is fixed on the fixed frame; and a suspended filler for attachment of microorganisms is placed in the anoxic tank. In order to create a suitable growth environment for anaerobic ammonium oxidation bacteria, the enrichment of the anaerobic ammonium oxidation bacteria is facilitated; the anaerobic ammonium oxidation bacteria can be enriched by utilizing sludge in the existing sewage treatment system, so that the sewage biochemical system in which the number of microorganisms is gradually dominant is achieved, and the addition of the anaerobic ammonium oxidation bacteria is avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of sewage treatment devices, and relates to an AAO treatment device with packing added. Background Technique

[0002] The AAO treatment device uses various microorganisms in activated sludge to decompose organic matter and remove nitrogen and phosphorus through a series of actions under anaerobic and aerobic conditions. In the traditional nitrification and denitrification nitrogen removal process, NH4 in wastewater needs to be + oxidized into NO2 by nitrite bacteria - and then oxidized into NO3 by nitrifying bacteria - which is the nitrification process; while NO3 - uses denitrifying bacteria to carry out denitrification reaction to generate N2 which is the denitrification process.

[0003] In the traditional nitrogen cycle theory, it is considered that heterotrophic denitrification is the only biological process for the generation of nitrogen gas in nature, and the discovery of the new nitrogen cycle process anaerobic ammonium oxidation has changed this understanding. Anaerobic ammonium oxidation (Anammox) refers to the biological process in which anaerobic ammonium oxidizing bacteria directly oxidize ammonia (NH 2- ) into nitrogen gas (N2) using nitrite (NO 4+ ) as the electron acceptor under anoxic conditions. It has the advantages of no need for external carbon source substances, high load, low surplus sludge production, etc., and has broad application prospects in the field of sewage denitrification.

[0004] However, in the existing applications of anaerobic ammonium oxidation in the AAO process, anaerobic ammonium oxidizing bacteria are added, so the anaerobic ammonium oxidizing bacteria need to be specially cultured and continuously added. Content of the Utility Model

[0005] The technical problem solved by the utility model is to provide an AAO treatment device with packing added, which can enrich anaerobic ammonium oxidizing bacteria in the anaerobic zone and anoxic zone by using the existing sludge system through the transformation of the anaerobic tank and the anoxic tank.

[0006] The utility model is realized through the following technical solutions:

[0007] An AAO treatment device with packing added, including an anaerobic tank, an anoxic tank and an aerobic tank, and packing for microorganisms to attach is added in the anaerobic tank and the anoxic tank;

[0008] The packing includes:

[0009] A fixed frame is arranged in the anaerobic tank, and packing ropes for microorganisms to attach are fixed on the fixed frame;

[0010] Suspended packing for microorganisms to attach is placed in the anoxic tank.

[0011] Furthermore, fixing frames are respectively arranged at the top and bottom of the anaerobic pond, serving as the upper and lower fixing points of the packing rope, and the packing rope is arranged in parallel along the vertical direction of the anaerobic pond.

[0012] Furthermore, the anaerobic pond is divided into several independent treatment ponds, the water inlet mode of each treatment pond is changed to bottom inlet and top outlet, and a water outlet weir is arranged at the water outlet.

[0013] The position where the water outlet weir is arranged is that the top of the water outlet weir is 500 mm from the top of the pond, and the length of the water outlet weir is the same as the width of the pond.

[0014] The usage amount of the packing in the anaerobic pond is 50 - 60% of the pond volume.

[0015] Furthermore, the anaerobic pond is divided into several connectable packing areas; suspended packing is placed in the packing areas.

[0016] The suspended packing is provided with porous channels, and the material of the suspended packing is HDPE.

[0017] The suspended packing is cylindrical with porous channels, the diameter of the plane circle is 20 - 25 mm, and the cylindrical thickness is 8 - 10 mm.

[0018] The usage amount of the suspended packing in the anoxic pond is 40 - 50% of the pond volume.

[0019] Compared with the prior art, the utility model has the following beneficial technical effects:

[0020] The AAO treatment device with added packing provided by the utility model transforms the anaerobic pond and the anoxic pond, adds packing to the anaerobic pond and the anoxic pond, creates a suitable growth environment for anaerobic ammonium-oxidizing bacteria, and facilitates the enrichment of anaerobic ammonium-oxidizing bacteria; and the anaerobic ammonium-oxidizing bacteria can be enriched by using the sludge in the existing sewage treatment system, reaching a sewage biochemical system in which the number of its microorganisms gradually occupies a dominant position, and avoiding the addition of anaerobic ammonium-oxidizing bacteria. Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the AAO sewage treatment device of the utility model;

[0022] Figure 2 It is one of the schematic cross-sectional views of the anaerobic pond of the utility model;

[0023] Figure 3 It is another schematic cross-sectional view of the anaerobic pond of the utility model;

[0024] Figure 4 It is a schematic diagram of the fixed packing in the anaerobic pond;

[0025] Figure 5 It is a schematic diagram of the suspended packing in the anoxic pond;

[0026] Among them, 1 is the effluent weir and 2 is the packing rope. Specific implementation mode

[0027] The following further describes the present utility model in detail with reference to embodiments, which is an explanation rather than a limitation of the present utility model.

[0028] See Figures 1 - 5 , an AAO treatment device with packing added, including an anaerobic tank, an anoxic tank and an aerobic tank, and packing for microorganisms to attach is added in the anaerobic tank and the anoxic tank;

[0029] The packing includes:

[0030] A fixed frame is arranged in the anaerobic tank, and packing ropes for microorganisms to attach are fixed on the fixed frame;

[0031] Suspended packing for microorganisms to attach is placed in the anoxic tank.

[0032] Further, see Figure 1 , the anaerobic tank is divided into several independent treatment tanks, the water inlet mode of each treatment tank is changed to bottom inlet and top outlet, and an effluent weir is arranged at the water outlet;

[0033] The anaerobic tank is divided into several connectable parts.

[0034] The following further explains the packing.

[0035] Specifically, the usage amount of the packing in the anaerobic tank is 50-60% of the tank volume;

[0036] Fixed frames are respectively arranged at the top and bottom of the anaerobic tank as the upper and lower fixing points of the packing rope, and the packing ropes are arranged in parallel along the vertical direction of the anaerobic tank.

[0037] The specific packing rope is as Figure 4 shown, a single-layer steel mesh is laid as the upper and lower fixing points of the packing rope, and the packing rope is tied to the upper and lower steel bars.

[0038] The thickness of the microorganisms attached to the packing rope is 400nm - 600nm. The outermost layer is attached with anaerobic bacteria, and the innermost layer is attached with anaerobic ammonium-oxidizing bacteria. The anaerobic bacteria degrade the organic matter in the sewage to produce carbon dioxide and water. The 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.

[0039] The packing rope can be made of elastic three-dimensional material, which can make the sewage and the biofilm fully mix and penetrate for contact and exchange. The biofilm can not only be evenly formed on the filaments in large quantities, maintain good activity, but also have good metabolism and will not adhere and agglomerate.

[0040] Specifically, the water outlet weir is made of carbon steel with anti-corrosion treatment, having a width of 600 mm, a height of 600 mm, and the length of the water outlet weir is the same as the width of the pool; the position of the water outlet weir is such that the top of the weir is 500 mm below the pool top to adapt to the change in the water outlet mode.

[0041] The usage amount of the suspended packing in the anoxic tank is 40 - 50% of the tank volume;

[0042] The material of the suspended packing is HDPE, and the suspended packing is provided with porous channels, and the shape of the channels is not limited, which can increase the attachment area of microorganisms;

[0043] See Figure 5 , the suspended packing is made into a cylindrical shape with porous channels, the diameter of the plane circle is 20 - 25 mm, and the columnar thickness is 8 - 10 mm.

[0044] The following gives an example of the enrichment of anaerobic ammonium - oxidizing bacteria.

[0045] Example 1

[0046] The AAO sewage treatment tank was transformed as follows and the anaerobic ammonium - oxidizing bacteria were enriched:

[0047] (1) Adding packing:

[0048] Packing was added to the anaerobic tank and the anoxic tank to enable the anaerobic ammonium - oxidizing bacteria to attach and grow on it;

[0049] Specifically, a single - layer steel mesh was laid on the top and bottom of the anaerobic tank as the upper and lower fixing points of the packing rope, and the packing rope was tied to the upper and lower steel bars; 60% of the three - dimensional packing of the tank volume was installed;

[0050] In the anoxic tank, 50% of the tank volume of suspended packing was installed, the material of the suspended packing was HDPE, and the suspended packing was provided with porous channels.

[0051] These packings provided a good living carrier for the anaerobic ammonium - oxidizing bacteria, enabling the anaerobic ammonium - oxidizing bacteria to enrich on them; the anaerobic ammonium - oxidizing bacteria were domesticated and cultured using the activated sludge in the original sewage treatment system.

[0052] 2) Control of dissolved oxygen (DO):

[0053] The dissolved oxygen in the anaerobic tank was controlled to be less than 0.2 mg / L, the dissolved oxygen in the anoxic tank was less than 0.3 mg / L, the dissolved oxygen in Aerobic Tank 1 (as Figure 1 shown, the aerobic tank was divided into Aerobic Tank 1, Aerobic Tank 2, and Aerobic Tank 3) was controlled between 0.2 - 0.5 mg / L, and the dissolved oxygen at the outlet of the aerobic tank was controlled between 0.3 - 0.5 mg / L;

[0054] 3) Control of sludge concentration:

[0055] Reduce the discharge of excess sludge from the secondary sedimentation tank, and increase the mixed liquor suspended solids (MLSS) concentration in the anaerobic tank and anoxic tank to 4,500 - 5,500 mg / L; meanwhile, increase the dosage of the phosphorus removal agent to 40 - 50 mg / L.

[0056] Specifically, monitor the sludge concentration according to the sludge concentration monitor. When the sludge concentration is high, turn on the excess sludge pump in the sludge pump house of the secondary sedimentation tank to discharge part of the sludge to the sludge thickening tank for treatment; if the sludge concentration is too low, reduce the sludge discharge, and the sludge concentration will gradually increase.

[0057] 4) Keep the COD in the anaerobic tank at 30 - 40 mg / L and the COD in the anoxic tank at 20 - 30 mg / L.

[0058] 5) Control of the reflux ratio: Adopt two - stage reflux, control the external reflux ratio at 60%, and control the internal reflux ratio at 200%.

[0059] 6) Control of the sludge age: While increasing the sludge concentration, increase the sludge age to 20 - 25 days, so that the absolute number of anaerobic ammonium - oxidizing bacteria gradually increases.

[0060] During the transformation and commissioning process, in order to ensure the stable compliance of the effluent indicators, step - by - step adjustment measures were taken, as follows:

[0061] 1. Adjustment of the sludge concentration

[0062] In the traditional operation process, the growth rate of anaerobic ammonium - oxidizing bacteria is lower than that of nitrite - oxidizing bacteria. The proliferation of nitrite - oxidizing bacteria will cause most of the ammonia to be converted into NO3 - , rather than N2. Therefore, we adopted the method of increasing the sludge concentration and lengthening the sludge age to gradually increase the absolute number of anaerobic ammonium - oxidizing bacteria. The increase in the number of anaerobic ammonium - oxidizing bacteria enhanced its competitive advantage over nitrite - oxidizing bacteria.

[0063] During the process of increasing the sludge concentration, increase the mixed liquor suspended solids (MLSS) concentration to 5,000 mg / L. The method is to reduce the discharge of excess sludge from the secondary sedimentation tank; since a large amount of fresh sewage enters the biochemical tank every day, the amount of microorganisms in the sewage continuously increases. If the excess sludge is not discharged, the sludge concentration in the biochemical tank will increase day by day.

[0064] In addition, pay attention to the changes in the effluent indicators. The increase in the sludge concentration will inevitably lead to a decrease in the phosphorus removal effect. Therefore, it is necessary to continuously increase the dosage of the phosphorus removal agent. The dosage of the phosphorus removal agent is increased from 25 mg / L to 50 mg / L.

[0065] 2. Control of DO (dissolved oxygen)

[0066] In the operation of the existing AAO process, it is difficult to cultivate anaerobic ammonium-oxidizing bacteria by controlling the dissolved oxygen in the aerobic tank at 2-4 mg / L. The practical solution is to first create an environment for the production of anaerobic ammonium-oxidizing bacteria by reducing the dissolved oxygen concentration artificially.

[0067] Anaerobic ammonium-oxidizing bacteria belong to strict anaerobic microorganisms and can only survive in an environment with an oxygen partial pressure lower 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 the DO is relatively low, the activity of Nitrobacter is weaker than that of anaerobic ammonium-oxidizing bacteria. Since in an environment with a dissolved oxygen of about 0.5 mg / L, anaerobic ammonium-oxidizing bacteria have strong activity, are suitable for growth and reproduction, and can degrade ammonia nitrogen in the water body. Generally, the dissolved oxygen for biological nitrification reaction is required to be controlled at 2-4 mg / L. Therefore, the aeration valve can be adjusted repeatedly. On the premise of ensuring that the ammonia nitrogen in the effluent meets the standard, continuously try to reduce the dissolved oxygen concentration flowing back to the anaerobic tank to provide an environment suitable for the growth of anaerobic ammonium-oxidizing bacteria, enable them to reproduce continuously, and finally reach a certain number, so as to cultivate anaerobic ammonium-oxidizing bacteria into the dominant flora.

[0068] Specifically, adjust the aeration valve of the biochemical tank, reduce the aeration volume of the valve of aerobic tank 1, and ensure that the dissolved oxygen is controlled at 0.2-0.5 mg / L;

[0069] Adjust the valve of aerobic tank 2 to control its dissolved oxygen at 0.3-0.5 mg / L;

[0070] Control the air supply valve of aerobic tank 3 to ensure that the dissolved oxygen at the outlet of the aerobic tank is controlled at 0.3-0.5 mg / L.

[0071] During the adjustment of the aeration valve, pay attention to the change of ammonia nitrogen in the effluent. If the ammonia nitrogen in the effluent increases, the aeration valve needs to be adjusted back, especially the valve of aerobic tank 3, which needs to be adjusted back and forth many times. Through the repeated adjustment of the aeration valve, it is also a process of gradually cultivating anaerobic ammonium-oxidizing bacteria.

[0072] 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 continuously adjust the aeration, and on the premise of ensuring that the ammonia nitrogen in the effluent meets the standard, continuously reduce the dissolved oxygen in the biochemical tank to the designed range to meet the environment for its survival.

[0073] 3. Regulation of the concentration of organic matter in wastewater

[0074] During the cultivation by the anaerobic ammonium oxidation process, the carbon in the influent needs to be reduced to a relatively low level. The presence of a high level of carbon will promote the growth of heterotrophic bacteria. The method adopted is to increase the sludge concentration and reduce the sludge BOD load. Because when the wastewater enters the anaerobic tank, with 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 forms acetic acid through the action of acid-producing bacteria, and the polyphosphate-accumulating organisms immediately absorb acetic acid, H + and electrons, and store them in the form of PHB in the cells of the polyphosphate-accumulating organisms. Under aerobic conditions, the polyphosphate-accumulating organisms decompose PHB to release energy, part of which is used for their own reproduction, and the other part is used for the absorption of inorganic phosphorus to form polyphosphate and store it in the cells.

[0075] Therefore, by regulating the high sludge concentration and 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 can be created for the cultivation of anaerobic ammonium oxidation bacteria.

[0076] 4. Control of the internal reflux ratio

[0077] The present utility model adopts an internal circulation of 200%. One of the functions is to dilute the influent, reduce the impact load, and create a stable growth environment for microorganisms. The other is to evenly distribute the pollution load in the system and keep the dissolved oxygen control stable.

[0078] 5. Control of the external reflux ratio

[0079] The external reflux flow rate is controlled at 60%.

[0080] 6. Control of the sludge age

[0081] The sludge age is controlled at 20 - 25 days.

[0082] Finally, after the commissioning of the anaerobic ammonium oxidation process is completed, the enrichment of anaerobic ammonium oxidation bacteria is obvious, the nitrogen removal effect is obvious, the carbon source is saved by 100%, the power consumption is reduced by 60%, and the phosphorus remover is also reduced by 60% compared with the traditional process.

[0083] The above-given embodiments are the relatively optimal examples for implementing the present utility model, and the present utility model is not limited to the above embodiments. Any non-essential addition or replacement made by those skilled in the art according to the technical features of the technical solution of the present utility model falls within the protection scope of the present utility model.

Claims

1. An AAO treatment device with added packing, comprising an anaerobic tank, an anoxic tank and an aerobic tank, characterized in that, Add fillers for microorganisms to attach to in the anaerobic tank and anoxic tank; The fillers include: Set a fixed frame in the anaerobic tank, and fix filler ropes for microorganisms to attach to on the fixed frame; Place suspended fillers for microorganisms to attach to in the anoxic tank.

2. The AAO treatment device with added packing according to claim 1, characterized in that Set fixed frames at the top and bottom of the anaerobic tank respectively as the upper and lower fixing points of the filler ropes, and the filler ropes are arranged in parallel along the vertical direction of the anaerobic tank.

3. The AAO treatment device with packing added as described in claim 1, characterized in that, Divide the anaerobic tank into several independent treatment tanks, change the water inlet mode of each treatment tank to bottom-in and top-out, and set a weir at the water outlet.

4. The AAO treatment device with packing added according to claim 3, wherein The position where the weir is set is that the top of the weir is 500 mm from the top of the tank, and the length of the weir is the same as the width of the water tank.

5. The AAO treatment device with added packing as described in claim 1, characterized in that, The usage amount of the fillers in the anaerobic tank is 50-60% of the tank volume.

6. The AAO treatment device with added packing according to claim 1, characterized in that, Divide the anaerobic tank into several connectable filler areas; place suspended fillers in the filler areas.

7. The AAO treatment device with added packing as described in claim 6, characterized in that, The suspended fillers are provided with porous channels, and the material of the suspended fillers is HDPE.

8. The AAO treatment device with added packing as described in claim 7, characterized in that, The suspended fillers are cylindrical with porous channels, the diameter of the planar circle is 20-25 mm, and the cylindrical thickness is 8-10 mm.

9. The AAO treatment device with added packing as described in claim 1, wherein, The usage amount of the suspended fillers in the anoxic tank is 40-50% of the tank volume.

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