CN105217890A - A is strengthened based on DEAMOX 2the apparatus and method of/O+ Biological Contact Oxidation Process biological carbon and phosphorous removal - Google Patents

Abstract

The device and method for biological nitrogen and phosphorus removal based on DEAMOX enhanced A ² /O+biological contact oxidation process belong to the field of activated sludge wastewater treatment. The device is mainly composed of water tank (1), A ² /O reaction device (3), secondary sedimentation tank (11) and biological contact oxidation reaction device (12) sequentially connected; The average hydraulic retention time HRT in the anoxic zone is used to achieve short-range denitrification and provide the reaction substrate nitrite nitrogen for the anaerobic ammonium oxidation bacteria. By adding biological fillers (9) in the anoxic zone (5) Bacteria provide a growth carrier, change the function of the anoxic zone (5) in the A ² /O+ biological contact oxidation process, strengthen short-range denitrification and Anammox (anammox reaction) on the basis of the original denitrification, and realize the depth of municipal sewage Nitrogen and phosphorus removal. The invention is suitable for urban sewage treatment with a low carbon-to-nitrogen ratio, has stable effluent quality, and has obvious advantages in energy saving and consumption reduction.

Description

Device and method for biological nitrogen and phosphorus removal based on DEAMOX enhanced A2/O+biological contact oxidation process

technical field

The invention relates to a device and method for deep nitrogen and phosphorus removal, which belong to the technical field of sewage treatment by activated sludge method, and are applicable to the technical field of sewage treatment such as upgrading of new sewage plants and old sewage plants, treatment of municipal sewage and industrial waste water, etc. .

Background technique

Excessive discharge of nutrients such as nitrogen and phosphorus is an important cause of eutrophication in closed water bodies, lakes and slow-flowing waters. Therefore, the discharge standards for nitrogen and phosphorus are increasingly tightened. my country's urban sewage has a relatively low C/N ratio, and the easily degradable carbon sources that can be used for anaerobic phosphorus release and denitrification denitrification are even lower, posing a great challenge to sewage treatment. At present, many sewage treatment plants in my country cannot stably meet the first-level A discharge standards of the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18918-2002), and the most critical thing is that the effluent TN cannot stably meet the standards.

Nitrification reaction requires nitrifying bacteria with long sludge age and aerobic conditions, denitrification requires short sludge age phosphorus accumulating bacteria and anaerobic conditions, and phosphorus uptake requires aerobic conditions, nitrifying bacteria and phosphorus accumulating bacteria exist in sludge age With contradictions. If the sludge age is too high, it is not conducive to the removal of phosphorus; if the sludge age is too low, nitrifying bacteria cannot survive, and if the sludge amount is too large, it will also affect the subsequent sludge treatment. Therefore, there is a gap between denitrification and phosphorus removal in the traditional activated sludge method. contradiction.

The organic matter removal efficiency of the biological contact oxidation method is high, and the amount of treated water is large, so it is widely used in the field of sewage treatment. The specific surface area of the biological contact oxidation method filler is large, which provides a huge biological habitat space, allowing a large number of organisms to attach and grow, and can form a high-density ecological system with good stability, and the film-hanging period is relatively shortened. , The hydraulic retention time is short, the required equipment is small, the site occupies a small area, and has a high sludge concentration, the system has a strong impact load resistance, and the sludge output is small. In addition, there is generally no sludge bulking during operation, no sludge return device, high oxygen utilization rate, simple operation, convenient maintenance, and low operating costs.

The existing denitrification process of urban sewage mainly converts ammonia nitrogen into nitrogen gas through nitrification and denitrification, so as to achieve the purpose of total nitrogen removal. The denitrification process is a key step in the removal of total nitrogen, and sufficient organic carbon sources are needed to ensure the denitrification effect. Therefore, it is particularly important to study the denitrification process of low-carbon sewage. The emergence of anaerobic ammonium oxidation technology makes it possible for autotrophic biological denitrification technology, which greatly reduces energy consumption and makes denitrification no longer rely on sufficient organic carbon sources. Therefore, this technology has become a research hotspot in recent years. Anammox bacteria use nitrite as an electron acceptor to oxidize ammonia nitrogen and use inorganic carbon as a carbon source to achieve the purpose of autotrophic biological denitrification. However, due to the relatively long generation cycle of anammox bacteria, anammox is mainly used for high ammonia nitrogen wastewater treatment, and with the application of actual anammox projects and the research on anammox granular sludge is increasing, It makes it possible to autotrophic denitrification of urban sewage.

DEAMOX (DEnitrifyingAMmoniumOXidation) process, a new biological denitrification process. It is a new denitrification process proposed by Mulder et al. of Delft University in the Netherlands in 2006 on the basis of anammox process combined with heterooxygen denitrification, which can effectively remove NH ₄ ⁺ -N and NO ₃ ^- - N waste water. That is, in a single reactor, the anaerobic ammonium oxidation reaction and the denitrification reaction are carried out simultaneously, and the electron donor of the anaerobic ammonium oxidation reaction comes from the NO ₂ ^- -N produced in the denitrification process. It no longer needs to control the difficult semi-short-range process, effectively solves the problem that NO ₂ ^- -N is difficult to obtain in the anammox process, and can remove the NO ₃ ^- -N produced in the anammox process in situ, thus compared with The concentration of TN in the effluent of the traditional anammox process can be effectively reduced.

Contents of the invention

The object of the present invention is to provide a device and method for deep nitrogen and phosphorus removal, which can realize short-range denitrification by controlling the average hydraulic retention time HRT in the anoxic zone under low C/N ratio conditions, and provide anaerobic ammonia oxidizing bacteria The reaction substrate is nitrite nitrogen. By adding biological fillers in the anoxic area to provide growth carriers for anammox bacteria, the function of the anoxic area is changed, and the short-term Denitrification, Anammox functions, ammonia nitrogen is provided in the raw water, and the biological contact oxidation tank performs a sufficient nitrification reaction to convert ammonia nitrogen into nitrate nitrogen, which is returned to the anoxic area through the pipeline to provide nitrate nitrogen, and the nitrate nitrogen enters the anoxic area for short-term Denitrification produces nitrite nitrogen, and the anammox bacteria on the biological filler in the anoxic zone use ammonia nitrogen and nitrite nitrogen to perform Anammox denitrification, so as to realize the denitrification and phosphorus removal of municipal sewage, which is conducive to the stable effluent reaching the "urban Pollutant Discharge Standards for Sewage Treatment Plants (GB18918-2002) Class A Discharge Standards.

The device for biological nitrogen and phosphorus removal based on DEAMOX enhanced A ² /O+biological contact oxidation process mainly consists of water tank (1), A ² /O reaction device (3), secondary sedimentation tank (11) and biological contact oxidation reaction device (12) The A ² /O reaction device (3) includes the anaerobic zone (4), the anoxic zone (5) and the aerobic zone (6); the water tank (1) is connected to the anaerobic zone ( 4) connection, the anaerobic zone (4) is connected with the anoxic zone (5), and the anoxic zone (5) is connected with the aerobic zone (6); the aerobic zone (6) passes through the A ² /O overflow pipe (10 ) is connected to the secondary settling tank (11); the bottom of the secondary settling tank (11) is connected to the anaerobic zone (4) through the sludge return pump (14), and the secondary settling tank (11) is connected to the biological contactor via the lift pump (17) The oxidation zone (7), the biological contact oxidation zone (7) is connected to the anoxic zone (5) through the nitrification liquid return pump (16), the biological contact oxidation reaction device (12) is provided with a water outlet (13), and the aerobic zone (6 ) and the biological contact oxidation zone (7) are provided with aeration devices. The biological filler (9) is placed in the anoxic zone (5), and its filling ratio is 15% to 25%; the biological filler (9) is placed in the biological contact oxidation zone (7), and its filling ratio is 30% to 45%; The filler (9) has a specific surface area of 500-800m ² /m ³ and a density of 0.96-1.00g/cm ³ .

The device for biological nitrogen and phosphorus removal based on DEAMOX enhanced A ² /O+biological contact oxidation process is characterized in that it includes the following steps:

1) Domestic sewage enters the anaerobic zone (4) of the A ² /O reaction device (3) from the water tank (1) through the water inlet pump (2), and simultaneously enters the bottom of the secondary settling tank (11) through sludge backflow The return sludge pumped back by the pump (14) undergoes anaerobic phosphorus release reaction in the anaerobic zone (4): DPAOS uses the volatile fatty acids VFAs in the raw water to synthesize PHAs as the internal carbon source, and releases phosphorus at the same time to control the anaerobic hydraulic pressure. The residence time HRT _anaerobic is 1.5 ~ 2.5h.

2) The mixed solution enters the anoxic zone (5) from the anaerobic zone (4), and at the same time enters the nitrification solution from the biological contact oxidation zone (7), controlling the anoxic hydraulic retention time HRT _anoxic to 2 to 4.5h , DPAOS uses nitrate nitrogen as the electron acceptor and PHAs as the electron donor to denitrify and absorb phosphorus; the refluxed nitrate nitrogen enters the anoxic zone and undergoes short-term denitrification to produce nitrite nitrogen, which is mixed with a large amount of ammonia nitrogen in the mixed solution. The anammox bacteria on the biological filler (9) in the anoxic zone utilize ammonia nitrogen and nitrite nitrogen to perform Anammox denitrification.

3) The mixed solution enters the aerobic zone (6) from the anoxic zone (5) to carry out an aerobic reaction: control the dissolved oxygen concentration to 1-1.5mg/L, control the _aerobic hydraulic retention time HRT to 0.5-1h, Perform aerobic removal of residual phosphorus in the mixed liquid. DPAOS uses oxygen as the electron acceptor and PHAs as the electron donor to absorb phosphorus aerobically and blow off nitrogen at the same time to prevent the sludge from decaying due to long-term anaerobic state.

4) The mixed solution enters the secondary sedimentation tank (11) from the aerobic zone (6) through the A ² /O overflow pipe (10) to realize the separation of mud and water, and the sewage containing ammonia nitrogen enters the biological contact oxidation reaction through the lift pump (11) In the biological contact oxidation zone (7) in the device (12), the bottom sludge is returned to the anaerobic zone (4) through the sludge return pump (14).

5) Nitrifying bacteria grow on the biological filler (9) in the biological contact oxidation zone (7), and the nitrifying bacteria oxidize ammonia nitrogen to nitrate nitrogen under aerobic conditions, and part of the nitrifying liquid flowing out of the biological contact oxidation reaction device (12) The nitrifying liquid returns to the anoxic zone (5) through the nitrifying liquid return pump (17), the nitrifying liquid return flow ratio is 200% to 300%, and the other part is discharged from the water outlet (13).

6) By discharging the mixed liquid, the MLSS of the activated sludge in the A ² /O reaction device (3) is maintained at 3000-4500 mg/L, and the sludge age is 11-14 days.

The device and method for biological nitrogen and phosphorus removal based on DEAMOX enhanced A ² /O+biological contact oxidation process is characterized in that, under the condition of low C/N ratio, short-range denitrification is realized by controlling the HRT in the anoxic zone, and nitrous Accumulate and provide reaction substrates for anammox bacteria; by adding biological fillers in the anoxic area to provide growth carriers for anammox bacteria, change the function of the anoxic area in the A ² /O+ biological contact oxidation process: short-term Denitrification, denitrification, and Anammox, that is, the ammonia nitrogen contained in the sewage entering the anoxic area through the anaerobic area, and the nitrification liquid returned from the aerobic area contains nitrate nitrogen, and short-term denitrification occurs to produce nitrite nitrogen. Anammox bacteria on biological fillers use ammonia nitrogen and nitrite nitrogen for Anammox denitrification.

The device and method for biological nitrogen and phosphorus removal based on DEAMOX enhanced A ² /O+biological contact oxidation process, compared with the traditional A ² /O process, has the following advantages in the state of pure culture strains:

1) Save 50% of the aeration volume. The traditional A ² /O process consumes 4.57gO ₂ theoretically to remove 1gNH ₄ ⁺ -N, and this process theoretically consumes 2.285gO ₂ , which greatly saves the aeration volume.

2) Save 60% of the carbon source dosage. The traditional A ² /O process removes 1gNH ₄ ⁺ -N theoretically to provide 2.86gCOD, and this process theoretically provides 1.14gCOD, which greatly saves the carbon source dosage.

3) Because the DEAMOX reaction process is partly autotrophic denitrification, the sludge output will be effectively reduced, which is conducive to reducing the cost of sludge disposal, saving energy and reducing consumption.

Description of drawings

Figure 1 is a device for biological nitrogen and phosphorus removal based on DEAMOX enhanced A ² /O+biological contact oxidation process.

In Figure 1: 1-water tank; 2-inlet pump; 3-A ² /O reaction device; 4-anaerobic zone; 5-anoxic zone; 6-aerobic zone; 7-biological contact oxidation zone; 8-stirring 9-biological filler; 10-A ² /O overflow pipe; 11-secondary sedimentation tank; 12-biological contact oxidation reaction device; 13-water outlet; 14-sludge return pump; 15-solenoid valve; 16- Nitrification liquid return pump; 17-lift pump; 18-microporous aeration head; 19-rotameter; 20-blower.

detailed description

In conjunction with Fig. 1, the embodiment of the present invention is described in detail:

1) Inoculate activated sludge from traditional sewage treatment plants with MLSS>8000mg/L, MLVSS/MLSS>0.65, and SV<45%, and add it to the A ² /O reaction device (3) to make the sludge concentration 4000mg/L L, after 18 days of stable operation, inoculate the biofiller (9) that has hung the anaerobic ammox biofilm in the anoxic zone (5), and the filling ratio is 30%; in the biological contact oxidation zone (7), add biological The filler (9) has a filling ratio of 40%; the biological filler (9) has a specific surface area of 500m ² /m ³ and a density of 0.98g/cm ³ .

2) The domestic sewage enters the anaerobic zone (4) of the A ² /O reaction device (3) from the water tank (1) through the water inlet pump (2), and simultaneously enters the bottom of the secondary settling tank (11) through sludge reflux The return sludge pumped back by the pump (14) is subjected to anaerobic phosphorus release reaction in the anaerobic zone (4), and the _anaerobic hydraulic retention time (HRT) is controlled to be 2 hours.

3) The mixed solution enters the _anoxic zone (5) from the anaerobic zone (4), and at the same time enters the nitrification solution from the biological contact oxidation zone (7). Nitrate nitrogen is the electron acceptor, and PHAs is the electron donor, denitrification absorbs phosphorus; the refluxed nitrate nitrogen enters the anoxic zone and undergoes short-term denitrification to produce nitrite nitrogen, which is mixed with a large amount of ammonia nitrogen in the mixed solution, and the anoxic zone The anammox bacteria on the inner biological filler (9) utilize ammonia nitrogen and nitrite nitrogen to perform Anammox denitrification.

4) The mixed solution enters the aerobic zone (6) from the anoxic zone (5) to carry out an aerobic reaction: control the dissolved oxygen concentration to 1.5 mg/L, control the aerobic hydraulic retention time HRT _aerobic to 1h, and carry out the aerobic reaction in the mixed solution. For the aerobic removal of remaining phosphorus, DPAOS uses oxygen as the electron acceptor and PHAs as the electron donor to aerobically absorb phosphorus while blowing off nitrogen to prevent the sludge from decaying due to long-term anaerobic state.

5) The mixed solution enters the secondary sedimentation tank (11) from the aerobic zone (6) through the A ² /O overflow pipe (10) to realize the separation of mud and water, and the sewage containing ammonia nitrogen enters the biological contact oxidation reaction through the lift pump (11) In the biological contact oxidation zone (7) in the device (12), the bottom sludge is returned to the anaerobic zone (4) through the sludge return pump (14), and the sludge return ratio is 100%.

6) Nitrifying bacteria grow on the biological filler (9) in the biological contact oxidation zone (7), and the nitrifying bacteria oxidize ammonia nitrogen to nitrate nitrogen under aerobic conditions, and part of the nitrifying liquid flowing out of the biological contact oxidation reaction device (12) Return to the anoxic zone (5) through the nitrating liquid return pump (17), the reflux ratio of the nitrifying liquid is 300%, and the other part is discharged from the water outlet (13).

7) By discharging the mixed liquor, keep the activated sludge MLSS in the A ² /O reaction unit (3) at 4000 mg/L and the sludge age at 14 days.

8) The test results show that after the system runs stably, the effluent COD concentration is 10-40mg/L, NH ₄ ⁺ -N concentration is 0-0.4mg/L, NO ₃ ^- -N concentration is 8-12mg/L, TN concentration It is 10-14mg/L.

Claims (2)

1. A device for biological nitrogen and phosphorus removal based on DEAMOX enhanced A2/O ⁺ biological contact oxidation process, characterized in that it consists of a water tank ( ¹ ), an A2/O reaction device (3), a secondary settling tank (11) and a biological contactor The oxidation reaction device (12) is connected in sequence, and the A ² /O reaction device (3) includes an anaerobic zone (4), anoxic zone (5) and an aerobic zone (6); the water tank (1) passes through the water inlet pump (2 ) is connected with the anaerobic zone (4), the anaerobic zone (4) is connected with the anoxic zone (5), and the anoxic zone (5) is connected with the aerobic zone (6); the aerobic zone (6) is connected by A ² / The O overflow pipe (10) is connected with the secondary settling tank (11); the bottom of the secondary settling tank (11) is connected with the anaerobic zone (4) through the sludge return pump (14), and the secondary settling tank (11) is passed through the lift pump ( 17) Connected to the biological contact oxidation zone (7), the biological contact oxidation zone (7) is connected to the anoxic zone (5) through the nitrifying liquid return pump (16), and the biological contact oxidation reaction device (12) is provided with a water outlet (13) , the aerobic zone (6) and the biological contact oxidation zone (7) are all provided with aeration devices; the agitator (8) is installed in the anaerobic zone (4) and the anoxic zone (5); The biological filler (9) has a filling ratio of 15% to 25%; the biological filler (9) is placed in the biological contact oxidation zone (7), and its filling ratio is 30% to 45%; the specific surface area of the biological filler (9) is 500 ～800m ² /m ³ , density 0.96～1.00g/cm ³ . 2. The method for applying the device according to claim 1 to carry out biological denitrification and dephosphorization, is characterized in that, comprising the following steps: 1) Domestic sewage enters the anaerobic zone (4) of the A ² /O reaction device (3) from the water tank (1) through the water inlet pump (2), and simultaneously enters the bottom of the secondary settling tank (11) through sludge backflow The return sludge pumped back by the pump (14) undergoes anaerobic phosphorus release reaction in the anaerobic zone (4), and controls the anaerobic hydraulic retention time HRT _anaerobic to 1.5-2.5h; 2) The mixed solution enters the anoxic zone (5) from the anaerobic zone (4), and at the same time enters the nitrification solution from the biological contact oxidation zone (7), controlling the anoxic hydraulic retention time HRT _anoxic to 2 to 4.5h ;; 3) The mixed solution enters the aerobic zone (6) from the anoxic zone (5) to carry out an aerobic reaction: control the dissolved oxygen concentration to 1-1.5mg/L, control the _aerobic hydraulic retention time HRT to 0.5-1h, Carry out aerobic removal of residual phosphorus in the mixed liquor; 4) The mixed solution enters the secondary sedimentation tank (11) from the aerobic zone (6) through the A ² /O overflow pipe (10) to realize the separation of mud and water, and the sewage containing ammonia nitrogen enters the biological contact oxidation zone through the lift pump (11) (7), the bottom sludge is returned to the anaerobic zone (4) through the sludge return pump (14), and the sludge return ratio is 75% to 125%; 5) A part of the nitrifying liquid flowing out from the biological contact oxidation reaction device (12) is returned to the anoxic zone (5) through the nitrifying liquid return pump (17), and the nitrifying liquid return flow ratio is 200% to 300%, and the other part flows from the water outlet (13 )emission; The activated sludge MLSS in the A ² /O reaction device (3) is kept at 3000-4500 mg/L, and the sludge age is 11-14 days.