Wastewater treatment device and method based on coupling of carbon source recovery and anaerobic ammonia oxidation

Abstract

The invention relates to the field and provides a wastewater treatment device and method based on coupling of carbon source recovery and anaerobic ammonia oxidation. The device comprises a biological flocculation tank, a vertical flow type sedimentation tank, an anaerobic digestion tank, a Sharon tank, a two-stage A / O composite denitrification device and a secondary sedimentation tank. The denitrification method based on coupling of carbon source recovery and anaerobic ammonia oxidation provided by the invention has the advantages of high-efficiency denitrification of domestic sewage with low carbon source consumption and recovery of biomass energy carbon source.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a wastewater treatment device and method based on carbon source recovery coupled with anaerobic ammonia oxidation. Background Art

[0002] Traditional sewage treatment processes, such as A2 / O and oxidation ditches, are limited by the process principles themselves and destructively remove carbon, nitrogen and phosphorus pollutants in the water. They have shortcomings such as high energy consumption, high carbon emissions and low resource recovery, which are in conflict with the current demand for energy conservation and emission reduction.

[0003] The emergence of anaerobic ammonium oxidation technology has made the carbon source recovery technology route of urban sewage feasible. Anaerobic ammonium oxidation is an autotrophic denitrification process. Compared with the traditional nitrification and denitrification process, the anaerobic ammonium oxidation process can save all carbon sources and about 60% of the oxygen demand. Due to the slow growth of anaerobic ammonium oxidizing bacteria, the amount of sludge produced by the reaction is small, and the sludge output is only about 10% of the traditional nitrification and denitrification, which reduces the sludge treatment cost. Based on the many advantages of anaerobic ammonium oxidation reaction, this process has been a research hotspot in the field of water treatment since its discovery. However, due to the characteristics of low ammonia nitrogen concentration and low temperature in urban sewage, the application of anaerobic ammonium oxidation technology in urban sewage has not yet been scaled up. Among them, the instability of the source of nitrite nitrogen, one of the substrates of anaerobic ammonium oxidizing bacteria, is one of the main reasons.

[0004] In view of the unstable source of nitrite nitrogen in the current anaerobic ammonium oxidation process in urban sewage treatment, it is urgent to establish a new denitrification method based on carbon source recovery coupled with anaerobic ammonium oxidation. Summary of the invention

[0005] The object of the present invention is to provide a wastewater treatment device and method based on carbon source recovery coupled with anaerobic ammonia oxidation.

[0006] In order to achieve the purpose of the present invention, in a first aspect, the present invention provides a wastewater treatment device based on carbon source recovery coupled with anaerobic ammonia oxidation, including a biological flocculation tank, a vertical flow sedimentation tank, an anaerobic digester, a Sharon tank, a two-stage A / O composite denitrification device and a secondary sedimentation tank.

[0007] Wherein, the biological flocculation tank is used to enrich the carbon source of insoluble organic matter in wastewater.

[0008] The vertical flow sedimentation tank is used to separate low-carbon and high-nitrogen water from concentrated sludge in the sludge mixture, and the effluent from the vertical flow sedimentation tank enters a two-stage A / O composite denitrification device.

[0009] The two-stage A / O composite denitrification device is composed of a primary anoxic tank, a secondary anoxic tank and an aerobic tank connected in series, each tank is separated by a partition, and a hole is provided on the partition, or each tank is connected by a pipeline; along the water flow direction, the water in the primary anoxic tank flows into the secondary anoxic tank, and the water in the secondary anoxic tank flows into the aerobic tank. A stirrer is provided above the primary anoxic tank and the secondary anoxic tank.

[0010] One side wall of the biological flocculation tank is connected to the wastewater inlet pipeline, and the other side wall is connected to one side wall of the vertical flow sedimentation tank through a first pipeline. The bottom of the vertical flow sedimentation tank is connected to the anaerobic digestion tank through a second pipeline, and the other side wall of the vertical flow sedimentation tank is connected to the first anoxic tank in the two-stage A / O composite denitrification device through a third pipeline; a mud-water separation agitator is also provided on the top of the vertical flow sedimentation tank.

[0011] An exhaust pipe is provided above one side wall of the anaerobic digester, and a mud discharge pipe is provided at the bottom; the other side wall of the anaerobic digester is connected to the Sharon tank through a liquid outlet pipe I; and a stirrer is also provided in the anaerobic digester.

[0012] The Sharon tank is connected to the secondary anoxic tank in the two-stage A / O composite denitrification device through a liquid outlet pipe II.

[0013] The water flowing out of the aerobic tank in the two-stage A / O composite denitrification device enters the secondary sedimentation tank through the liquid outlet pipe III, and is separated from the mud and water through the deep treatment of the secondary sedimentation tank. The discharged sludge enters the anaerobic digestion tank through the second pipeline.

[0014] The sludge is anaerobic digested in the anaerobic digestion tank and biogas is generated to realize the recovery of carbon source; wherein the anaerobic digested sludge contains facultative anaerobic bacteria and obligate anaerobic bacteria.

[0015] The supernatant separated from the anaerobic digestion tank enters the Sharon tank, and after the ammonia nitrogen in the supernatant is converted into nitrite nitrogen by controlling DO, it enters the secondary anoxic tank.

[0016] The filler filled in the Sharon pool is polyethylene, and the filling rate is 10-40%.

[0017] The low-carbon, high-nitrogen water flowing out of the vertical flow sedimentation tank and the aerobic nitrification liquid flowing out of the aerobic tank are refluxed into the primary anoxic tank (denitrifying bacteria grow naturally), and denitrification is carried out using the denitrifying bacteria in the primary anoxic tank.

[0018] An anaerobic ammonium oxidation reaction (natural growth of anaerobic ammonium oxidizing bacteria) occurs in the secondary anoxic tank.

[0019] In the aerobic pool, ammonia nitrogen is converted into nitric nitrogen through nitrification reaction.

[0020] Furthermore, the filling rate of the filler in the primary anoxic pool is 10-40%. The filler can be found in CN201611250004.0, and includes the following components in parts by weight: 94-97 parts of high-density polyethylene, 2-4 parts of calcium carbonate, 0.7-0.9 parts of stearic acid or stearate, 0.3-0.5 parts of carbonate, 0.08-0.12 parts of polyhydroxy fatty acid amide, 0.08-0.12 parts of trace elements, 0.08-0.12 parts of biological enzymes, and 0.01-0.0 3 parts, 0.03-0.05 parts of ultraviolet absorber and 0.02-0.04 parts of peroxide additive; wherein the trace elements are mixed by trace elements in organisms and trace elements in non-biological organisms in a weight ratio of 1:5-1:2, the trace elements in organisms are cobalt, the trace elements in non-biological organisms are rare earths, the biological enzyme is alkaline protease, the antioxidant is p-phenylenediamine, the ultraviolet absorber is benzophenone, and the peroxide additive is di-tert-butyl peroxide.

[0021] The filler of the secondary anoxic pool is the same as the filler of the primary anoxic pool, and the filling rate is 10-40%.

[0022] The filler of the aerobic pool is polyethylene, and the filling rate is 10-40%.

[0023] In a second aspect, the present invention provides application of the device in wastewater treatment (denitrification).

[0024] In a third aspect, the present invention provides a wastewater treatment method based on carbon source recovery coupled with anaerobic ammonium oxidation, and the wastewater is denitrified using the device, comprising the following steps: Step 1: After primary treatment of the wastewater by pretreatment systems such as screens, grit settling or regulating tanks to remove suspended solids, it enters the biological flocculation tank to enrich the carbon source in the wastewater; Step 2: The sludge mixed liquid obtained in step 1 enters a vertical flow sedimentation tank to separate the low-carbon and high-nitrogen wastewater from the concentrated sludge; Step 3: A portion of the precipitated sludge is returned to the biological flocculation tank through the second pipeline connected to the bottom of the vertical flow sedimentation tank to control the diversion and return to the biological flocculation tank again to ensure that the sludge precipitated has a certain sludge concentration; part of the remaining sludge enters the anaerobic digestion tank through the second pipeline connected to the bottom of the vertical flow sedimentation tank for treatment; Step 4: The sludge entering the anaerobic digester in step 3 generates biogas through the anaerobic digestion process of the sludge to achieve carbon source recovery; Step 5: After the anaerobic digestion process in step 4, the agitator stops stirring, and the supernatant produced after static sedimentation separation enters the Sharon tank. By controlling the DO at 0.8-2.5 mg / L, the ammonia nitrogen in the supernatant is converted into nitrite nitrogen, and then enters the secondary anoxic tank to provide a stable source of nitrite nitrogen for the secondary anoxic tank to achieve anaerobic ammonia oxidation reaction; Step 6: The low-carbon and high-nitrogen wastewater separated in step 2 is subjected to a two-stage anoxic A / O composite denitrification process; wherein the aerobic nitrification liquid is internally refluxed to the primary anoxic tank, together with the low-carbon and high-nitrogen wastewater (containing organic matter) entering the primary anoxic tank, and denitrified by a denitrification process in the primary anoxic tank; Step 7: The effluent entering the secondary anoxic tank in step 6 undergoes anaerobic ammonia oxidation reaction to further reduce the ammonia nitrogen concentration; Step 8: After step 7, the effluent from the secondary anoxic tank enters the aerobic tank, and the remaining ammonia nitrogen in the wastewater is completely converted into nitric nitrogen through the nitrification process by nitrifying bacteria. The remaining refractory organic matter in the primary anoxic tank is further mineralized in the aerobic tank and converted into CO2, so that the effluent COD concentration meets the standard; at the same time, the effluent from the aerobic tank enters the secondary sedimentation tank through the liquid outlet pipe; Step 9: The effluent entering the secondary sedimentation tank is subjected to deep treatment for mud-water separation to further remove suspended solids in the water; at the same time, the detached and aged biofilm is further collected and enters the anaerobic digester through the second pipeline together with the residual sludge in the biological flocculation tank.

[0025] Furthermore, the specific processing conditions are: The HRT of the bioflocculation tank is 20 min~2 h (preferably 30 min), and the flow rate is not higher than 20,000 m 3 / d, water temperature not lower than 10℃, pH 6~9.

[0026] The two-stage A / O composite denitrification device is an MBBR process with an HRT of 8~20 h, of which the HRT of the first anoxic tank is 2~4 h, the HRT of the second anoxic tank is 2~4 h, and the HRT of the aerobic tank is 4~12 h; The temperature of the primary anoxic pool, secondary anoxic pool and aerobic pool shall not be lower than 10℃, and the pH shall be 6~9.

[0027] By means of the above technical solution, the present invention has at least the following advantages and beneficial effects: (1) The present invention recovers carbon sources from urban sewage to produce methane.

[0028] (ii) Introduce autotrophic nitrogen removal technology, combine autotrophic nitrogen removal with heterotrophic nitrogen removal, and improve nitrogen removal efficiency.

[0029] (III) By recycling the carbon source of biomass energy, the dependence on additional carbon sources during the processing process is reduced, low carbon source consumption is achieved, and operating costs are reduced.

[0030] (IV) The use of multi-stage treatment units such as biological flocculation tank, vertical flow sedimentation tank, anaerobic digester, Sharon tank, two-stage A / O composite denitrification device and secondary sedimentation tank ensures the stability of the treatment effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a denitrification process flow chart based on carbon source recovery coupled with anaerobic ammonia oxidation. 100-biological flocculation tank, 110-first pipeline, 200-vertical flow sedimentation tank, 210-third pipeline, 220-second pipeline, 230-mud and water separation agitator, 300-two-stage anoxic A / O composite denitrification process unit, 310-first anoxic tank, 320-second anoxic tank, 330-aerobic tank, 340-liquid outlet pipe III, 350-nitrification liquid reflux pipe, 400-second sedimentation tank, 410-mud and water separation agitator, 500-anaerobic digestion tank, 510-exhaust pipe, 520-agitator, 530-agitator, 540-liquid outlet pipe I, 600-Sharon tank, 610-liquid outlet pipe II. DETAILED DESCRIPTION

[0032] The existing bottlenecks of anaerobic ammonia oxidation process are as follows: low temperature leads to low activity of anaerobic ammonia oxidizing bacteria and unstable effluent water quality; high carbon-nitrogen concentration ratio causes heterotrophic bacteria to compete for living space and substrate; low ammonia nitrogen concentration in water quality makes it difficult to effectively realize the nitrite process. The present invention provides a denitrification method based on carbon source recovery coupled with anaerobic ammonia oxidation. By combining autotrophic denitrification with heterotrophic denitrification, the problem of unstable nitrite nitrogen source is addressed by using anaerobic digestion supernatant with high ammonia nitrogen concentration for nitrite, producing nitrite nitrogen, and providing a stable and reliable source of nitrite nitrogen for anaerobic ammonia oxidizing bacteria in the anoxic tank. At the same time, the MBBR system is used in a graded manner to make heterotrophic denitrifying bacteria and autotrophic denitrifying bacteria grow on fillers in different environments, respectively, thereby affecting the growth of anaerobic ammonia oxidizing bacteria, as well as the problem of slow growth of anaerobic ammonia oxidizing bacteria due to high carbon-nitrogen ratio.

[0033] The present invention adopts the following technical solution: The present invention provides a denitrification method based on carbon source recovery coupled with anaerobic ammonia oxidation, comprising a biological flocculation tank 100, a vertical flow sedimentation tank 200, a two-stage anoxic A / O composite denitrification process unit 300, a primary anoxic tank 310, a secondary anoxic tank 320, an aerobic tank 330, a secondary sedimentation tank 400, an anaerobic digestion tank 500 and a Sharon tank 600.

[0034] The biological flocculation tank 100 and the vertical flow sedimentation tank 200 constitute a biological adsorption unit. The biological flocculation tank 100 is used to enrich the carbon source of insoluble organic matter in sewage. The side wall of the biological flocculation tank 100 is connected to the outlet of the water inlet pipeline; the sewage enters the biological flocculation tank through the water inlet pipeline.

[0035] The vertical flow sedimentation tank 200 is used to separate low carbon high nitrogen sewage from concentrated sludge in the sludge mixture. The vertical flow sedimentation tank 200 is connected to the biological flocculation tank 100 through a first pipeline 110. The sedimentation tank 200 is connected to the anaerobic digestion tank 500 through a second pipeline 220.

[0036] Furthermore, the vertical flow sedimentation tank 200 is also connected to a two-stage anoxic A / O composite denitrification process unit 300 consisting of a primary anoxic tank 310 , a secondary anoxic tank 320 , and an aerobic tank 330 through a third pipeline 210 .

[0037] In the two-stage anoxic A / O composite denitrification process unit 300, the first anoxic tank uses the remaining carbon source to perform denitrification and consume the carbon source. The second anoxic tank contains anaerobic ammonium oxidation biofilm suspended filler, which can use ammonia nitrogen and nitrite nitrogen in water for anaerobic ammonium oxidation.

[0038] Furthermore, the filling rate of the anaerobic ammonia-oxidizing bacteria biofilm filler in the secondary anoxic tank is 10-30%.

[0039] The present invention provides a denitrification method based on carbon source recovery coupled with anaerobic ammonium oxidation, comprising the following steps: Step 1: The sewage after primary treatment by removing suspended matter through pretreatment systems such as screens, grit settling or regulating tanks enters the biological flocculation tank 100 to use the flocculation and adsorption effect of activated sludge on insoluble organic matter in the sewage, quickly and efficiently enrich the carbon source in the influent water, and utilize the resources.

[0040] Step 2: The sludge mixture obtained in step 1 enters the vertical flow sedimentation tank 200 to separate the low-carbon and high-nitrogen sewage from the concentrated sludge (there is a mud-water separation agitator 230 on the top of the sedimentation tank); wherein, the low-carbon and high-nitrogen sewage enters the subsequent two-stage anoxic A / O composite denitrification process unit 300 through the liquid outlet pipe 210 (the third pipeline) on the side surface of the vertical flow sedimentation tank.

[0041] Step 3: A portion of the precipitated sludge is returned to the biological flocculation tank 100 through the outlet pipe 220 (second pipeline) at the bottom of the sedimentation tank to control the diversion, so as to ensure that the sludge precipitated has a certain sludge concentration; part of the remaining sludge is controlled to enter the anaerobic digestion tank 500 for treatment through the outlet pipe 220 (second pipeline) at the bottom of the sedimentation tank.

[0042] Step 4: The organic matter in the sludge entering the anaerobic digester 500 in step 3 is decomposed and converted into biogas by facultative anaerobic bacteria and obligate anaerobic bacteria through the anaerobic digestion process of sludge under anaerobic conditions. The generated biogas is discharged through the discharge pipe (exhaust pipe) 510 above the side surface of the anaerobic digester, thereby realizing the recovery of carbon source.

[0043] Step 5: After the anaerobic digestion process in step 4, the agitators 520 and 530 stop stirring, and the supernatant produced after static sedimentation separation enters the Sharon tank 600 through the outlet pipe 540 (outlet pipe I) on the side surface to convert ammonia nitrogen, and convert ammonia nitrogen into nitrite nitrogen by controlling DO. At the same time, it is pumped into the secondary anoxic tank through the outlet pipe 610 (outlet pipe II) on the side surface of the Sharon tank, providing a stable source of nitrite nitrogen for the secondary anoxic tank of the two-stage anoxic A / O composite denitrification process to meet the anaerobic ammonia oxidation reaction.

[0044] Step 6: The effluent entering the two-stage anoxic A / O composite denitrification process unit 300 in step 2 is further treated. Among them, the aerobic nitrification liquid is refluxed to the primary anoxic tank 310. The primary anoxic tank 310 receives the effluent (containing organic matter) from the sedimentation tank 200 and the aerobic nitrification liquid refluxed internally, and reacts with the nitric nitrogen in the reflux liquid in the primary anoxic tank 310 to perform denitrification. The nitrification liquid reflux pipe 350 is used to reflux the nitrification liquid in the aerobic tank to the primary anoxic tank for denitrification.

[0045] Step 7: The effluent entering the secondary anoxic tank 320 through step 6 undergoes anaerobic ammonia oxidation reaction, and the ammonia nitrogen concentration in the secondary anoxic tank 320 is further reduced, with almost no available organic matter.

[0046] Step 8: The effluent entering the aerobic tank 330 through step 7 is converted into nitric nitrogen by nitrifying bacteria through the nitrification process. The remaining difficult-to-degrade organic matter in the primary anoxic tank 310 is further mineralized in the aerobic tank 330 and converted into CO2, so that the COD concentration of the effluent meets the standard; at the same time, the effluent of the aerobic tank 330 enters the secondary sedimentation tank 400 through the side surface outlet pipe 340 (outlet pipe III).

[0047] Step 9: The effluent from step 8 enters the secondary sedimentation tank 400 for deep treatment to separate mud from water (there is a mud-water separation agitator 410 on the top of the secondary sedimentation tank) to further remove suspended solids in the water; at the same time, the detached and aged biofilm is further collected and connected to the main sludge discharge pipe 220 together with the residual sludge from the biological flocculation tank 100 to enter the anaerobic digestion tank 500.

[0048] The denitrification process flow chart of the present invention based on carbon source recovery coupled with anaerobic ammonium oxidation is shown in Figure 1 .

[0049] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art, and the raw materials used are all commercially available products.

[0050] Example 1 Wastewater treatment device and method based on carbon source recovery coupled with anaerobic ammonium oxidation

[0051] Step 1: The sewage after primary treatment by removing suspended matter through pretreatment systems such as screens, grit settling or regulating tanks enters the biological flocculation tank 100 to use the flocculation and adsorption effect of activated sludge on insoluble organic matter in the sewage, quickly and efficiently enrich the carbon source in the influent water, and utilize the resources.

[0052] Step 2: The sludge mixture obtained in step 1 enters the vertical flow sedimentation tank 200 to separate the low-carbon and high-nitrogen sewage from the concentrated sludge (there is a mud-water separation agitator 230 on the top of the sedimentation tank); wherein, the low-carbon and high-nitrogen sewage enters the subsequent two-stage anoxic A / O composite denitrification process unit 300 through the liquid outlet pipe 210 (the third pipeline) on the side surface of the vertical flow sedimentation tank.

[0053] Step 3: A portion of the precipitated sludge is returned to the biological flocculation tank 100 through the outlet pipe 220 (second pipeline) at the bottom of the sedimentation tank to control the diversion, so as to ensure that the sludge precipitated has a certain sludge concentration; part of the remaining sludge is controlled to enter the anaerobic digestion tank 500 for treatment through the outlet pipe 220 (second pipeline) at the bottom of the sedimentation tank.

[0054] Step 4: The organic matter in the sludge entering the anaerobic digester 500 in step 3 is decomposed and converted into biogas by facultative anaerobic bacteria and obligate anaerobic bacteria through the anaerobic digestion process of sludge under anaerobic conditions. The generated biogas is discharged through the discharge pipe (exhaust pipe) 510 above the side surface of the anaerobic digester, thereby realizing the recovery of carbon source.

[0055] Step 5: After the anaerobic digestion process in step 4, the agitators 520 and 530 stop stirring, and the supernatant produced after static sedimentation separation enters the Sharon tank 600 through the outlet pipe 540 (outlet pipe I) on the side surface to convert ammonia nitrogen, and convert ammonia nitrogen into nitrite nitrogen by controlling DO. At the same time, it is pumped into the secondary anoxic tank through the outlet pipe 610 (outlet pipe II) on the side surface of the Sharon tank, providing a stable source of nitrite nitrogen for the secondary anoxic tank of the two-stage anoxic A / O composite denitrification process to meet the anaerobic ammonia oxidation reaction.

[0056] Step 6: The effluent entering the two-stage anoxic A / O composite denitrification process unit 300 in step 2 is further treated. Among them, the aerobic nitrification liquid is refluxed to the primary anoxic tank 310. The primary anoxic tank 310 receives the effluent (containing organic matter) from the sedimentation tank 200 and the aerobic nitrification liquid refluxed internally, and reacts with the nitric nitrogen in the reflux liquid in the primary anoxic tank 310 to perform denitrification. The nitrification liquid reflux pipe 350 is used to reflux the nitrification liquid in the aerobic tank to the primary anoxic tank for denitrification.

[0057] Step 7: The effluent entering the secondary anoxic tank 320 through step 6 undergoes anaerobic ammonia oxidation reaction, and the ammonia nitrogen concentration in the secondary anoxic tank 320 is further reduced, with almost no available organic matter.

[0058] Step 8: The effluent entering the aerobic tank 330 through step 7 is converted into nitric nitrogen by nitrifying bacteria through the nitrification process. The remaining difficult-to-degrade organic matter in the primary anoxic tank 310 is further mineralized in the aerobic tank 330 and converted into CO2, so that the COD concentration of the effluent meets the standard; at the same time, the effluent of the aerobic tank 330 enters the secondary sedimentation tank 400 through the side surface outlet pipe 340 (outlet pipe III).

[0059] Step 9: The effluent from step 8 enters the secondary sedimentation tank 400 for deep treatment to separate mud from water (there is a mud-water separation agitator 410 on the top of the secondary sedimentation tank) to further remove suspended solids in the water; at the same time, the detached and aged biofilm is further collected and connected to the main sludge discharge pipe 220 together with the residual sludge from the biological flocculation tank 100 to enter the anaerobic digestion tank 500.

[0060] Repeat step 4. The denitrification device process based on carbon source recovery coupled with anaerobic ammonia oxidation provided by the present invention forms a closed-loop cycle, which can not only convert sewage into clean water that can meet discharge standards, but also convert part of the carbon source in the sewage into energy, thereby achieving the purpose of carbon source recovery.

[0061] Furthermore, the filler filled in the Sharon pool is a suspended filler (polyethylene material) with a filling rate of 30%.

[0062] The fillers in the primary anoxic tank and the secondary anoxic tank can be found in Example 1 of the CN201611250004.0 specification, and the filling rate is 20%.

[0063] Among them, denitrifying bacteria grow naturally in the primary anoxic tank, and anaerobic ammonia-oxidizing bacteria grow naturally in the secondary anoxic tank.

[0064] The filler of the aerobic pool is made of polyethylene with a filling rate of 20%.

[0065] It should be noted that the two-stage anoxic A / O composite denitrification process unit 300 also adopts the MBBR process form, and the microbial community structure of the suspended carrier biofilm in different pools is quite different. For example, the biofilm of the first-stage anoxic pool 310 is mainly composed of heterotrophic denitrifying bacteria, the biofilm of the second-stage anoxic pool 320 is enriched with more anaerobic ammonia-oxidizing bacteria, and the biofilm of the aerobic pool 330 is enriched with a large number of nitrifying bacteria. A graded approach is adopted to achieve the ultimate goal of growing heterotrophic denitrifying bacteria and autotrophic denitrifying bacteria on fillers in different environments, respectively, to support the growth of anaerobic ammonia-oxidizing bacteria. The final ammonia nitrogen removal rate is >90%, the TN removal rate is >70%, and the COD removal rate is >80%.

[0066] Furthermore, the specific processing conditions are: The HRT of the bioflocculation tank is 30 min, and the flow rate is not higher than 20,000 m 3 / d, water temperature not lower than 10℃, pH around 7.2.

[0067] The two-stage A / O composite denitrification device adopts MBBR process with HRT of 11 h, of which the HRT of the primary anoxic tank is 3 h, the HRT of the secondary anoxic tank is 3 h, and the HRT of the aerobic tank is 5 h; the temperature of the primary anoxic tank, the secondary anoxic tank and the aerobic tank is not lower than 10°C, and the pH is 7.2~7.5.

[0068] In summary, the present invention provides a denitrification method based on carbon source recovery coupled with anaerobic ammonium oxidation, which mainly solves the technical problem that the anaerobic ammonium oxidation technology has poor denitrification effect in urban sewage treatment due to the limitation of unstable nitrite nitrogen source for anaerobic ammonium oxidizing bacteria in anoxic tanks. The denitrification method based on carbon source recovery coupled with anaerobic ammonium oxidation includes: a biological adsorption unit, the unit includes a biological flocculation tank and a middle sedimentation tank, the side surface of the biological flocculation tank is connected to a water inlet, the top of the middle sedimentation tank is provided with a mud-water separation agitator, and is respectively connected to the biological flocculation tank, the anaerobic digester and the primary anoxic tank; an anaerobic digester, the anaerobic digester is connected to the liquid inlet at the bottom of the middle sedimentation tank and the secondary sedimentation tank, the side surface is connected to the Sharon tank, the gas exhaust pipe is connected above the side surface, the bottom mud outlet pipe is connected to the biological flocculation tank, and the agitator is connected from the upper surface ; Two-stage A / O composite denitrification unit, the unit is provided with a two-stage A / O composite denitrification device (including a primary anoxic, a secondary anoxic and an aerobic tank body) and a secondary sedimentation tank, aeration pipes are inserted above the primary anoxic tank and the secondary anoxic tank, the side surfaces of the two-stage A / O composite denitrification device are respectively connected to the middle sedimentation tank and the secondary sedimentation tank, the bottom liquid inlet of the secondary anoxic tank is connected to the Sharon tank, the top of the secondary sedimentation tank is provided with a mud-water separation agitator, and the bottom discharge pipe is connected to the anaerobic digestion tank; Sharon tank, the Sharon tank is respectively connected to the anaerobic digestion tank and the secondary anoxic tank. The denitrification method based on carbon source recovery coupled with anaerobic ammonia oxidation provided by the present invention achieves the advantages of efficient denitrification of domestic sewage with low carbon source consumption and recovery of biomass energy carbon source.

[0069] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A wastewater treatment device based on carbon source recovery coupled with anaerobic ammonium oxidation, characterized in that: It includes biological flocculation tank, vertical flow sedimentation tank, anaerobic digestion tank, Sharon tank, two-stage A / O composite denitrification device and secondary sedimentation tank; Wherein, the biological flocculation tank is used to enrich the carbon source of insoluble organic matter in wastewater; The vertical flow sedimentation tank is used to separate the low carbon and high nitrogen water from the concentrated sludge in the sludge mixture, and the effluent from the vertical flow sedimentation tank enters the two-stage A / O composite denitrification device; The two-stage A / O composite denitrification device is composed of a primary anoxic tank, a secondary anoxic tank and an aerobic tank connected in series, each tank is separated by a partition, and a hole is provided on the partition, or each tank is connected by a pipeline; along the water flow direction, the water in the primary anoxic tank flows into the secondary anoxic tank, and the water in the secondary anoxic tank flows into the aerobic tank; a stirrer is provided above the primary anoxic tank and the secondary anoxic tank; One side wall of the biological flocculation tank is connected to the wastewater inlet pipeline, and the other side wall is connected to one side wall of the vertical flow sedimentation tank through a first pipeline. The bottom of the vertical flow sedimentation tank is connected to the anaerobic digestion tank through a second pipeline, and the other side wall of the vertical flow sedimentation tank is connected to the first anoxic tank in the two-stage A / O composite denitrification device through a third pipeline; a mud-water separation agitator is also provided on the top of the vertical flow sedimentation tank; An exhaust pipe is provided above one side wall of the anaerobic digester, and a mud discharge pipe is provided at the bottom; the other side wall of the anaerobic digester is connected to the Sharon tank through a liquid outlet pipe I; and a stirrer is also provided in the anaerobic digester; The Sharon tank is connected to the secondary anoxic tank in the two-stage A / O composite denitrification device through a liquid outlet pipe II; The water flowing out of the aerobic tank in the two-stage A / O composite denitrification device enters the secondary sedimentation tank through the liquid outlet pipe III, and is separated from the mud and water through the deep treatment of the secondary sedimentation tank. The discharged sludge enters the anaerobic digestion tank through the second pipeline.

2. The device according to claim 1, characterized in that Anaerobic digestion of sludge is performed in the anaerobic digestion tank to generate biogas to achieve carbon source recovery; Among them, anaerobic digestion sludge contains facultative anaerobes and obligate anaerobes.

3. The device according to claim 2, characterized in that The supernatant separated from the anaerobic digester enters the Sharon tank, and after the ammonia nitrogen in the supernatant is converted into nitrite nitrogen by controlling DO, it enters the secondary anoxic tank; The filler filled in the Sharon pool is polyethylene, and the filling rate is 10-40%.

4. The device according to claim 1, characterized in that The low-carbon and high-nitrogen water flowing out of the vertical flow sedimentation tank and the aerobic nitrification liquid flowing out of the aerobic tank are refluxed into the primary anoxic tank, and denitrification is performed by the denitrifying bacteria in the primary anoxic tank; An anaerobic ammonium oxidation reaction occurs in the secondary anoxic tank; In the aerobic pool, ammonia nitrogen is converted into nitric nitrogen through nitrification reaction; The filling rate of the filler in the primary anoxic pool is 10-40%, and the filler includes the following components in parts by weight: 94-97 parts of high-density polyethylene, 2-4 parts of calcium carbonate, 0.7-0.9 parts of stearic acid or stearate, 0.3-0.5 parts of carbonate, 0.08-0.12 parts of polyhydroxy fatty acid amide, 0.08-0.12 parts of trace elements, 0.08-0.12 parts of biological enzymes, 0.01-0.03 parts of antioxidants, and 0.0 3 to 0.05 parts and 0.02 to 0.04 parts of a peroxide additive; wherein the trace elements are formed by mixing trace elements in organisms and trace elements in non-organisms at a weight ratio of 1:5 to 1:2, the trace elements in organisms are cobalt, the trace elements in non-organisms are rare earths, the biological enzyme is alkaline protease, the antioxidant is p-phenylenediamine, the ultraviolet absorber is benzophenone, and the peroxide additive is di-tert-butyl peroxide; The filler of the secondary anoxic pool is the same as the filler of the primary anoxic pool, and the filling rate is 10-40%; The filler of the aerobic pool is polyethylene, and the filling rate is 10-40%.

5. Use of the device according to any one of claims 1 to 4 in wastewater treatment.

6. A wastewater treatment method based on carbon source recovery coupled with anaerobic ammonium oxidation, characterized in that: Denitrification of wastewater using the device according to any one of claims 1 to 4 comprises the following steps: Step 1: The wastewater after primary treatment by the screen, grit settling or regulating tank pretreatment system to remove suspended matter enters the biological flocculation tank to enrich the carbon source in the wastewater; Step 2: The sludge mixed liquid obtained in step 1 enters a vertical flow sedimentation tank to separate the low-carbon and high-nitrogen wastewater from the concentrated sludge; Step 3: A portion of the precipitated sludge is returned to the biological flocculation tank again through a second pipeline connected to the bottom of the vertical flow sedimentation tank to control the diversion, so as to ensure that the precipitated sludge has a certain sludge concentration; Part of the remaining sludge enters the anaerobic digestion tank for treatment through the second pipeline connected to the bottom of the vertical flow sedimentation tank; Step 4: The sludge entering the anaerobic digester in step 3 generates biogas through the anaerobic digestion process of the sludge to achieve carbon source recovery; Step 5: After the anaerobic digestion process in step 4, the agitator stops stirring, and the supernatant produced after static sedimentation separation enters the Sharon tank. By controlling the DO at 0.8-2.5 mg / L, the ammonia nitrogen in the supernatant is converted into nitrite nitrogen, and then enters the secondary anoxic tank to provide a stable source of nitrite nitrogen for the secondary anoxic tank to achieve anaerobic ammonia oxidation reaction; Step 6: The low-carbon and high-nitrogen wastewater separated in step 2 is subjected to a two-stage anoxic A / O composite denitrification process; wherein the aerobic nitrification liquid is internally refluxed to the primary anoxic tank, and together with the low-carbon and high-nitrogen wastewater entering the primary anoxic tank, denitrification is carried out in the primary anoxic tank by a denitrification process; Step 7: The effluent entering the secondary anoxic tank in step 6 undergoes anaerobic ammonia oxidation reaction to further reduce the ammonia nitrogen concentration; Step 8: After step 7, the effluent from the secondary anoxic tank enters the aerobic tank, and the remaining ammonia nitrogen in the wastewater is completely converted into nitric nitrogen through the nitrification process by nitrifying bacteria. The remaining refractory organic matter in the primary anoxic tank is further mineralized in the aerobic tank and converted into CO2, so that the effluent COD concentration meets the standard; at the same time, the effluent from the aerobic tank enters the secondary sedimentation tank through the liquid outlet pipe; Step 9: The effluent entering the secondary sedimentation tank is subjected to deep treatment for mud-water separation to further remove suspended solids in the water; at the same time, the detached and aged biofilm is further collected and enters the anaerobic digester through the second pipeline together with the residual sludge in the biological flocculation tank.

7. The method according to claim 6, characterized in that The specific processing conditions are: The HRT of the biological flocculation tank is 20 min~2 h, and the flow rate is not higher than 20,000 m 3 / d, water temperature not less than 10℃, pH 6~9; The two-stage A / O composite denitrification device is an MBBR process with an HRT of 8~20 h, of which the HRT of the first anoxic tank is 2~4 h, the HRT of the second anoxic tank is 2~4 h, and the HRT of the aerobic tank is 4~12 h; The temperature of the primary anoxic pool, secondary anoxic pool and aerobic pool shall not be lower than 10℃, and the pH shall be 6~9.

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