Organic nitrogen metabolism type anaerobic ammonia oxidation denitrification process

Abstract

The invention discloses an organic nitrogen metabolism type anaerobic ammonia oxidation denitrification process, and belongs to the technical field of sewage treatment. According to the process, in an anaerobic ammonia oxidation reactor, an anaerobic ammonia oxidation enrichment culture is used as an inoculum to treat the organic nitrogen wastewater; in the treatment process, the anaerobic ammonia oxidation enrichment culture takes nitrite as an electron acceptor and takes organic nitrogen as an electron donor, and the organic nitrogen and the nitrite are converted into nitrogen. The organic nitrogen is used as an electron donor, so that the organic nitrogen can be efficiently removed, and the problem of organic nitrogen wastewater treatment is solved. The denitrification process flow is simple, an aeration unit is not needed, and the advantages of energy conservation and consumption reduction are remarkable; in addition, nitrate and ammonia nitrogen are not accumulated, total nitrogen can be completely removed, and secondary nitrogen pollution is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and in particular relates to an organic nitrogen metabolism type anaerobic ammonia oxidation denitrification process. Background Art

[0002] With the increasingly stringent pollutant discharge standards for urban sewage treatment plants in my country, such as Beijing and Tianjin, which have raised the Class A standard to Class IV surface water (total nitrogen ≤ 1.5 mg / L, ammonia nitrogen ≤ 1.0 mg / L), the treatment of industrial organic nitrogen wastewater, represented by leather wastewater, faces severe challenges. Dimethylformamide, a typical pollutant in leather wastewater, is a synthetic organic nitrogen source with a concentration of over 60% and is highly toxic (LC 50 <100mg / L), a low carbon-nitrogen ratio (C / N≈3), and resistance to biodegradation (BOD5 / COD<0.3). This lack of natural degrading bacteria and metabolic enzymes requires large amounts of exogenous carbon sources (methanol dosages of 300-500mg / L) to maintain denitrification, resulting in doubled treatment costs and difficulty meeting effluent total nitrogen standards. Therefore, it is urgent to develop new, low-cost, and high-efficiency denitrification technologies to overcome engineering bottlenecks.

[0003] Anaerobic ammonium oxidation (Anammox) is a biological denitrification process that uses ammonium as an electron donor to oxidize nitrite to nitrogen gas. Compared to traditional nitrification-denitrification processes, anaerobic ammonium oxidation (Anammox) has the advantages of requiring no aeration or external carbon source, and producing less sludge. This significantly reduces the process footprint and operating costs, and is considered a core process for biological low-carbon wastewater treatment.

[0004] The core of the anaerobic ammonium oxidation process is anaerobic ammonium oxidizing bacteria. Traditionally, anaerobic ammonium oxidizing bacteria are considered to be completely autotrophic bacteria, but with the in-depth development of experimental techniques such as omics, many studies have shown that small-molecule organic matter can enter the acetyl-CoA pathway of anaerobic ammonium oxidizing bacteria, promoting the activity of anaerobic ammonium oxidizing bacteria. Therefore, anaerobic ammonium oxidizing bacteria are considered to have the ability to metabolize organic matter, and based on this, it is further speculated that they have the potential for organic nitrogen metabolism. The advantages of the organic nitrogen metabolism-type anaerobic ammonium oxidation denitrification process are that it can achieve efficient removal of organic nitrogen, solving the problem of organic nitrogen wastewater treatment; there is no need to set up an aerobic aeration unit, and the advantages of energy saving and consumption reduction are significant; no additional carbon source is required, which greatly reduces operating costs; the nitrate and ammonium salt concentrations in the effluent are low, and efficient and complete denitrification can be achieved. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies in the prior art and provide an organic nitrogen metabolism type anaerobic ammonium oxidation denitrification process.

[0006] The specific technical solutions adopted in the present invention are as follows:

[0007] The present invention provides an organic nitrogen metabolism-type anaerobic ammonium oxidation denitrification process, which is characterized in that, in an anaerobic ammonium oxidation reactor, an anaerobic ammonium oxidation enrichment culture is used as an inoculum to treat organic nitrogen wastewater; during the treatment process, the anaerobic ammonium oxidation enrichment culture uses nitrite as an electron acceptor and organic nitrogen as an electron donor to convert organic nitrogen and nitrite into nitrogen gas.

[0008] Preferably, the molar ratio of nitrite to organic nitrogen in the organic nitrogen wastewater is 1.35±0.2.

[0009] Furthermore, the organic nitrogen concentration in the organic nitrogen wastewater is 3-500 mg / L, and the nitrite concentration is 60-600 mg N / L.

[0010] Preferably, the inoculation concentration of the anaerobic ammonium oxidation enrichment culture is 5 to 30 g VSS / L.

[0011] Preferably, the inoculum form of the anaerobic ammonium oxidation enrichment culture is granular sludge or biofilm.

[0012] Preferably, in the anaerobic ammonium oxidation reactor, the dissolved oxygen is controlled below 0.5 mg / L, the reaction temperature is controlled at 25-35° C., and the pH value is controlled at 7.2±0.5.

[0013] Preferably, the anaerobic ammonium oxidation reactor is an anaerobic granular sludge expanded bed reactor, an upflow anaerobic sludge blanket or a sequencing batch activated sludge reactor.

[0014] Preferably, the hydraulic retention time of the anaerobic ammonium oxidation reactor is set to 3.6 to 48 hours, and the reflux ratio is set to 0.1 to 3.0.

[0015] Preferably, the organic nitrogen is dimethylformamide.

[0016] Preferably, before the anaerobic ammonium oxidation enrichment culture is inoculated into the anaerobic ammonium oxidation reactor, it is acclimated with a culture medium containing dimethylformamide and sodium nitrite to obtain an organic nitrogen metabolism-type anaerobic ammonium oxidation mixed culture; the molar ratio of nitrite to organic nitrogen in the culture medium is 1.0 to 3.0, the dissolved oxygen concentration is controlled below 0.5 mg / L during the acclimation process, the reaction temperature is 25 to 35°C, the pH value is 7.2±0.5, and the hydraulic retention time is 3.6 to 48 h.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] In the denitrification process provided by the present invention, the anaerobic ammonium oxidation (ANAMMOX) enrichment culture can use organic nitrogen as an electron donor, achieving efficient organic nitrogen removal and effectively resolving the challenge of organic nitrogen wastewater treatment. Compared to traditional organic nitrogen biological removal processes, the present invention offers a simple process flow, eliminates the need for an aeration unit, and offers significant energy savings and cost reductions. Furthermore, compared to autotrophic ANAMMOX processes, the present invention avoids nitrate accumulation and achieves complete total nitrogen removal. Furthermore, compared to traditional organic nitrogen biological removal processes, the present invention also exhibits no significant ammonia nitrogen accumulation, achieving complete total nitrogen removal and effectively avoiding secondary nitrogen pollution.

[0019] The examples of the present invention show that the total nitrogen load of the denitrification process can exceed 1.23 kg N / (m 3 ·d), dimethylformamide load can exceed 2.93kg / (m 3 ·d), currently, the maximum reaction rate is 1.15kg N / (m 3 ·d), the organic nitrogen removal efficiency can reach 100%, and the maximum nitrogen removal efficiency is about 99%. DETAILED DESCRIPTION

[0020] The present invention will be further described and illustrated below in conjunction with specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly without conflict.

[0021] The anaerobic ammonium oxidizing enrichment cultures inoculated in the following examples were all acclimated and cultured using a medium containing dimethylformamide and sodium nitrite. The molar ratio of nitrite to organic nitrogen in the medium was 1.0 to 3.0. During the acclimation process, the dissolved oxygen concentration was controlled below 0.5 mg / L, the reaction temperature was 25 to 35°C, the pH was 7.2 ± 0.5, and the hydraulic retention time was 3.6 to 48 hours. After acclimation, an organic nitrogen metabolizing anaerobic ammonium oxidizing mixed culture was obtained.

[0022] Example 1

[0023] This embodiment provides an organic nitrogen metabolism-based anaerobic ammonium oxidation denitrification process, which is as follows:

[0024] (1) Preparation of organic nitrogen wastewater

[0025] The concentration of dimethylformamide was 80 mg N / L, and the concentration of sodium nitrite was 96 mg N / L. Additionally, 140 mg / L KHCO₃, 800 mg / L NaHCO₃, 17.5 mg / L KH₂PO₄, 17.5 mg / L CaCl₂, 300 mg / LMgSO₄·7H₂O, and 1 mL / L of trace elements were added. The molar ratio of organic nitrogen to nitrite in the simulated wastewater was 1:1.2.

[0026] (2) Treatment of simulated organic nitrogen wastewater

[0027] In an anaerobic ammonium oxidation reactor, a culture of organic nitrogen-metabolizing anaerobic ammonium-oxidizing bacteria was inoculated at a concentration of 23.47 g VSS / L for denitrification. During the treatment, the dissolved oxygen concentration was controlled below 0.5 mg / L, the reaction temperature was 33°C, the initial pH was 7.2, and the hydraulic retention time was 18 hours.

[0028] Organic nitrogen metabolism-based anaerobic ammonium oxidation (ANAMMOX) mixed cultures use nitrite as an electron acceptor and organic nitrogen as an electron donor, converting organic nitrogen and nitrite into nitrogen gas. Testing has shown that this process can simultaneously remove organic nitrogen and nitrite, with an actual molar ratio of 1:1.25. The total nitrogen removal efficiency in the effluent reached 98.18%, and the organic nitrogen removal efficiency reached 100%.

[0029] Example 2

[0030] This embodiment provides an organic nitrogen metabolism-based anaerobic ammonium oxidation denitrification process, which is as follows:

[0031] (1) Preparation of organic nitrogen wastewater

[0032] The concentration of dimethylformamide was 180 mg N / L, and the concentration of sodium nitrite was 217 mg N / L. Additionally, 140 mg / L KHCO₃, 800 mg / L NaHCO₃, 17.5 mg / L KH₂PO₄, 17.5 mg / L CaCl₂, 300 mg / L MgSO₄·7H₂O, and 1 mL / L of trace elements were added. The molar ratio of organic nitrogen to nitrite in the simulated wastewater was 1:1.2.

[0033] (2) Treatment of simulated organic nitrogen wastewater

[0034] In an anaerobic ammonium oxidation reactor, a culture of organic nitrogen-metabolizing anaerobic ammonium-oxidizing bacteria was inoculated at a concentration of 26.40 g VSS / L for denitrification. During the treatment, the dissolved oxygen concentration was controlled below 0.5 mg / L, the reaction temperature was 33°C, the initial pH was 7.4, and the hydraulic retention time was 18 hours.

[0035] Organic nitrogen metabolism-based anaerobic ammonium oxidation (ANAMMOX) mixed cultures use nitrite as an electron acceptor and organic nitrogen as an electron donor, converting organic nitrogen and nitrite into nitrogen gas. Testing has shown that this process can simultaneously remove organic nitrogen and nitrite, with an actual molar ratio of 1:1.36. The total nitrogen removal efficiency in the effluent reached 92.36%, and the organic nitrogen removal efficiency reached 100%.

[0036] Example 3

[0037] This embodiment provides an organic nitrogen metabolism-based anaerobic ammonium oxidation denitrification process, which is as follows:

[0038] (1) Preparation of organic nitrogen wastewater

[0039] The concentration of dimethylformamide was 260 mg N / L, and the concentration of sodium nitrite was 312 mg N / L. Additionally, 140 mg / L KHCO₃, 800 mg / L NaHCO₃, 17.5 mg / L KH₂PO₄, 17.5 mg / L CaCl₂, 300 mg / L MgSO₄·7H₂O, and 1 mL / L of trace elements were added. The molar ratio of organic nitrogen to nitrite in the simulated wastewater was 1:1.2.

[0040] (2) Treatment of simulated organic nitrogen wastewater

[0041] In an anaerobic ammonium oxidation reactor, a culture of organic nitrogen-metabolizing anaerobic ammonium-oxidizing bacteria was inoculated at a concentration of 26.40 g VSS / L for denitrification. During the treatment, the dissolved oxygen concentration was controlled below 0.5 mg / L, the reaction temperature was 33°C, the initial pH was 7.2, and the hydraulic retention time was 18 hours.

[0042] Organic nitrogen metabolism-based anaerobic ammonium oxidation (ANAMMOX) mixed cultures use nitrite as an electron acceptor and organic nitrogen as an electron donor, converting organic nitrogen and nitrite into nitrogen gas. Testing has shown that this process can simultaneously remove organic nitrogen and nitrite, with an actual molar ratio of 1:1.38. The total nitrogen removal efficiency in the effluent reached 94.05%, and the organic nitrogen removal efficiency reached 100%.

[0043] Example 4

[0044] This embodiment provides an organic nitrogen metabolism-based anaerobic ammonium oxidation denitrification process, which is as follows:

[0045] (1) Preparation of organic nitrogen wastewater

[0046] The concentration of dimethylformamide was 300 mg N / L, and the concentration of sodium nitrite was 360 mg N / L. Additionally, 140 mg / L KHCO₃, 800 mg / L NaHCO₃, 17.5 mg / L KH₂PO₄, 17.5 mg / L CaCl₂, 300 mg / L MgSO₄·7H₂O, and 1 mL / L of trace elements were added. The molar ratio of organic nitrogen to nitrite in the simulated wastewater was 1:1.2.

[0047] (2) Treatment of simulated organic nitrogen wastewater

[0048] In an anaerobic ammonium oxidation reactor, a culture of organic nitrogen-metabolizing anaerobic ammonium-oxidizing bacteria was inoculated at a concentration of 27.00 g VSS / L for denitrification. During the treatment, the dissolved oxygen concentration was controlled below 0.5 mg / L, the reaction temperature was 35°C, the initial pH was 7.2, and the hydraulic retention time was 18 hours.

[0049] The organic nitrogen metabolism-based anaerobic ammonium oxidation (ANAMMOX) mixed culture uses nitrite as an electron acceptor and organic nitrogen as an electron donor, converting organic nitrogen and nitrite into nitrogen gas. Testing has shown that this process can simultaneously remove organic nitrogen and nitrite, with an actual molar ratio of 1:1.46. The total nitrogen removal efficiency in the effluent reached 90.18%, and the organic nitrogen removal efficiency reached 100%.

[0050] Example 5

[0051] This embodiment provides an organic nitrogen metabolism-based anaerobic ammonium oxidation denitrification process, which is as follows:

[0052] (1) Preparation of organic nitrogen wastewater

[0053] The concentration of dimethylformamide was 420 mg N / L, and the concentration of sodium nitrite was 504 mg N / L. Additionally, 140 mg / L KHCO₃, 800 mg / L NaHCO₃, 17.5 mg / L KH₂PO₄, 17.5 mg / L CaCl₂, 300 mg / L MgSO₄·7H₂O, and 1 mL / L of trace elements were added. The molar ratio of organic nitrogen to nitrite in the simulated wastewater was 1:1.2.

[0054] (2) Treatment of simulated organic nitrogen wastewater

[0055] In an anaerobic ammonium oxidation reactor, a culture of organic nitrogen-metabolizing anaerobic ammonium-oxidizing bacteria was inoculated at a concentration of 21.13 g VSS / L for denitrification. During the treatment, the dissolved oxygen concentration was kept below 0.5 mg / L, the reaction temperature was 35°C, the initial pH was 7.2, and the hydraulic retention time was 18 hours.

[0056] The organic nitrogen metabolism-based anaerobic ammonium oxidation (ANAMMOX) mixed culture uses nitrite as an electron acceptor and organic nitrogen as an electron donor, converting organic nitrogen and nitrite into nitrogen gas. Testing has shown that this process can simultaneously remove organic nitrogen and nitrite, with an actual molar ratio of 1:1.52. The total nitrogen removal efficiency in the effluent reached 90.34%, and the organic nitrogen removal efficiency reached 98.84%.

[0057] The embodiment described above is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Persons skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent substitution or equivalent transformation falls within the scope of protection of the present invention.

Claims

1. An organic nitrogen metabolism type anaerobic ammonium oxidation denitrification process, characterized in that: In the anaerobic ammonium oxidation reactor, the anaerobic ammonium oxidation enrichment culture is used as the inoculum to treat the organic nitrogen wastewater; during the treatment process, the anaerobic ammonium oxidation enrichment culture uses nitrite as the electron acceptor and organic nitrogen as the electron donor to convert organic nitrogen and nitrite into nitrogen gas.

2. The organic nitrogen metabolism-type anaerobic ammonium oxidation denitrification process according to claim 1, characterized in that: The molar ratio of nitrite to organic nitrogen in the organic nitrogen wastewater is 1.35±0.

2.

3. The organic nitrogen metabolism-type anaerobic ammonium oxidation denitrification process according to claim 2, characterized in that: The organic nitrogen concentration in the organic nitrogen wastewater is 3-500 mg / L, and the nitrite concentration is 60-600 mg N / L.

4. The organic nitrogen metabolism-type anaerobic ammonium oxidation denitrification process according to claim 1, characterized in that: The inoculation concentration of the anaerobic ammonium oxidation enrichment culture is 5 to 30 g VSS / L.

5. The organic nitrogen metabolism-type anaerobic ammonium oxidation denitrification process according to claim 1, characterized in that: The inoculum form of the anaerobic ammonium oxidation enrichment culture is granular sludge or biofilm.

6. The organic nitrogen metabolism-type anaerobic ammonium oxidation denitrification process according to claim 1, characterized in that: In the anaerobic ammonium oxidation reactor, the dissolved oxygen is controlled below 0.5 mg / L, the reaction temperature is controlled at 25-35° C., and the pH value is controlled at 7.2±0.

5.

7. The organic nitrogen metabolism-type anaerobic ammonium oxidation denitrification process according to claim 1, characterized in that: The anaerobic ammonium oxidation reactor adopts an anaerobic granular sludge expanded bed reactor, an upflow anaerobic sludge bed or a sequencing batch activated sludge reactor.

8. The organic nitrogen metabolism-type anaerobic ammonium oxidation denitrification process according to claim 1, characterized in that: The hydraulic retention time of the anaerobic ammonium oxidation reactor is set to 3.6 to 48 hours, and the reflux ratio is set to 0.1 to 3.

0.

9. The organic nitrogen metabolism-type anaerobic ammonium oxidation denitrification process according to claim 1, characterized in that: The organic nitrogen is dimethylformamide.

10. The organic nitrogen metabolism-type anaerobic ammonium oxidation denitrification process according to claim 1, characterized in that: Before the anaerobic ammonium oxidation enrichment culture is inoculated into the anaerobic ammonium oxidation reactor, it is acclimated using a culture medium containing dimethylformamide and sodium nitrite to obtain an organic nitrogen metabolism-type anaerobic ammonium oxidation mixed culture; the molar ratio of nitrite to organic nitrogen in the culture medium is 1.0 to 3.0, the dissolved oxygen concentration is controlled below 0.5 mg / L during the acclimation process, the reaction temperature is 25 to 35° C., the pH value is 7.2±0.5, and the hydraulic retention time is 3.6 to 48 hours.