A method for treating nitrogen-containing wastewater

Abstract

The present invention belongs to the field of environmental protection, and in particular, relates to a method for treating nitrogen-containing wastewater, comprising the following steps: a) under aerobic conditions, mixing and taming highly efficient denitrifying and denitrifying bacteria and tamed nitrifying bacteria sludge to obtain synchronous nitrification and denitrification activated sludge; the highly efficient denitrifying and denitrifying bacteria are Zorberella; b) under aerobic conditions, using the synchronous nitrification and denitrification activated sludge to perform biological denitrification treatment on the nitrogen-containing wastewater to obtain treated wastewater. The method provided by the present invention uses denitrifying bacteria with highly efficient denitrification capabilities under both anoxic and aerobic conditions and nitrifying bacteria sludge with high treatment efficiency after taming, and tames the two synchronously to construct a synchronous nitrification and denitrification sludge system to treat nitrogen-containing industrial wastewater. The method can perform synchronous nitrification and denitrification treatment on wastewater under aerobic conditions, and achieve synchronous and efficient removal of ammonia nitrogen and total nitrogen in wastewater.

Description

Technical Field

[0001] The invention belongs to the field of environmental protection, and in particular relates to a method for treating nitrogen-containing wastewater. Background Art

[0002] With the continuous acceleration of the industrialization process, more and more nitrogen-containing wastewater is produced. At present, the main method for domestic sewage denitrification is biological denitrification. Biological denitrification mainly uses microorganisms to remove nitrogen-containing pollutants in sewage through nitrification and denitrification. At present, the mainstream sewage treatment process still uses the traditional activated sludge process. 2 O, oxidation ditch, CASS, etc. The traditional sewage treatment process is generally carried out in different reactors or forms an alternating anoxic and aerobic environment (SBR) in time or space in the same reactor. It has the disadvantages of complex system, high energy consumption, high alkalinity and carbon source consumption, and high infrastructure cost.

[0003] With the development of technology, people have found that nitrification and denitrification reactions can be carried out simultaneously in the same reactor, which is called simultaneous nitrification and denitrification process (SND). SND has outstanding advantages over traditional denitrification processes. For example, it can achieve simultaneous denitrification in the same reactor, greatly reducing infrastructure costs and floor space; it can save 40% of organic carbon sources in the denitrification stage, and the alkali produced can partially neutralize the acid produced in the nitrification process, greatly reducing operating costs, which is in line with the national requirements for energy conservation, emission reduction, carbon neutrality, and carbon peak.

[0004] There are currently three theories on the formation mechanism of simultaneous nitrification and denitrification, namely, macro-environmental explanation, micro-environmental theory and biological explanation. The macro-environmental SND process mainly uses the suspended activated sludge method. Since the formation of micro-anoxic zones in sludge flocs is affected by many factors, it is difficult to maintain stability, resulting in large fluctuations in its treatment effect; the micro-environmental SND process mainly uses granular sludge for biological denitrification, but the acclimation cycle of granular sludge is long, and the types of microorganisms that form granular sludge are uncertain, resulting in large differences in its treatment effect with different systems; from the perspective of microbial theory, if efficient aerobic denitrifying bacteria can be found, efficient denitrification can be achieved by fine-tuning the existing traditional sewage treatment process, and at the same time, fluctuations in treatment effects caused by uncertainty in microbial species can be avoided.

[0005] At present, although many simultaneous nitrification and denitrification processes or methods have been reported, either the treatment efficiency is low or a sewage treatment reactor with a special structure is required to be implemented, which is difficult to achieve in the current mainstream sewage treatment plants. Summary of the invention

[0006] In view of this, the object of the present invention is to provide a method for treating nitrogen-containing wastewater. The method provided by the present invention can perform simultaneous nitrification and denitrification treatment on wastewater under aerobic conditions, thereby achieving simultaneous and efficient removal of ammonia nitrogen and total nitrogen in the wastewater. It has a wide temperature adaptability range, high tolerance, and a high total nitrogen removal rate. Moreover, the method can be directly implemented in an aerobic tank without the need for new equipment or process modifications.

[0007] The present invention provides a method for treating nitrogen-containing wastewater, comprising the following steps:

[0008] a) under aerobic conditions, mixing and acclimating the highly efficient denitrifying and denitrifying bacteria and the acclimated nitrifying bacteria sludge to obtain the synchronous nitrification and denitrification activated sludge;

[0009] The highly efficient denitrification and denitrification bacteria is Zobellella denitrificans LBSW21-01, with a deposit number of CGMCC No. 22730;

[0010] b) Under aerobic conditions, the nitrogen-containing wastewater is subjected to biological denitrification treatment using the simultaneous nitrification and denitrification activated sludge to obtain treated wastewater.

[0011] Preferably, the domesticated nitrifying bacteria sludge is obtained according to the following steps:

[0012] The nitrifying bacteria sludge is added into the nitrogen-containing water body, and the nitrifying bacteria in the sludge are gradually domesticated by gradually increasing the ammonia nitrogen concentration of the water body to obtain the domesticated nitrifying bacteria sludge.

[0013] Preferably, the specific conditions of the gradient acclimation include:

[0014] The initial ammonia nitrogen concentration is set at 50-500 mg / L; the final ammonia nitrogen concentration is increased to 600-1500 mg; when the ammonia nitrogen concentration in the acclimation system decreases to below 10 mg / L, the ammonia nitrogen concentration is increased, and the increase in the ammonia nitrogen concentration each time is 50-200 mg / L.

[0015] Preferably, the ammonia oxidation performance of the domesticated nitrifying bacteria sludge is 80-550 mgNH 4 + -N / (L·h).

[0016] Preferably, the highly efficient denitrifying and denitrifying bacteria are first inoculated into a denitrifying liquid culture medium for activation to obtain an activated bacterial solution before participating in mixed domestication.

[0017] Preferably, the effective viable bacteria count of the activated bacterial solution is 2×10 9 ~4×10 10 cfu / mL.

[0018] Preferably, the volume ratio of the activated bacterial solution and the domesticated nitrifying bacteria sludge during mixing and domestication is 1:(1-5).

[0019] Preferably, the dissolved oxygen concentration of the mixed domestication is 1-8 mg / L; the pH value of the mixed domestication is 6.5-9.5; the ammonia nitrogen concentration of the mixed domestication is 100-1000 mg / L; the C / N ratio of the mixed domestication is 2-7; and the temperature of the mixed domestication is 10-43°C.

[0020] Preferably, when performing the mixed domestication, trace elements are added to the domestication system.

[0021] Preferably, the ammonia nitrogen concentration of the nitrogen-containing wastewater is 100-1000 mg / L; the dissolved oxygen concentration of the biological denitrification treatment is 1-8 mg / L; the pH value of the biological denitrification treatment is 6.5-9.5; the C / N ratio of the biological denitrification treatment is 2-7; and the temperature of the biological denitrification treatment is 10-43°C.

[0022] Compared with the prior art, the present invention provides a method for treating nitrogen-containing wastewater. The method provided by the present invention comprises the following steps: a) under aerobic conditions, high-efficiency denitrification and denitrification bacteria and domesticated nitrifying bacteria sludge are mixed and domesticated to obtain synchronous nitrification and denitrification activated sludge; the high-efficiency denitrification and denitrification bacteria are Zobellella denitrificans LBSW21-01, and the deposit number is CGMCC No.22730; b) under aerobic conditions, the nitrogen-containing wastewater is subjected to biological denitrification treatment using the synchronous nitrification and denitrification activated sludge to obtain treated wastewater. The method provided by the present invention uses denitrifying bacteria with high denitrification ability under both anoxic and aerobic conditions and nitrifying bacteria sludge with high treatment efficiency after domestication, and the two are synchronously domesticated to construct a synchronous nitrification and denitrification sludge system to treat nitrogen-containing industrial wastewater. The method can perform synchronous nitrification and denitrification treatment on wastewater under aerobic conditions, and realize the synchronous and efficient removal of ammonia nitrogen and total nitrogen in wastewater. The method provided by the present invention has a wide temperature adaptability range, high tolerance, and a high total nitrogen removal rate. It can simultaneously achieve the removal of ammonia nitrogen and total nitrogen in the same reactor, is suitable for the treatment of various nitrogen-containing wastewaters, has the advantages of low investment, low cost, and high treatment efficiency, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0024] Figure 1 It is a bar graph showing the effects of different bacterial species ratios on the removal of total nitrogen by simultaneous nitrification and denitrification provided in Example 1 of the present invention;

[0025] Figure 2 is a bar graph showing the effect of different C / N ratios on simultaneous nitrification and denitrification provided in Example 2 of the present invention;

[0026] Figure 3 This is a bar graph showing the effects of different dissolved oxygen concentrations on simultaneous nitrification and denitrification provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The present invention provides a method for treating nitrogen-containing wastewater, comprising the following steps:

[0029] a) under aerobic conditions, mixing and acclimating the highly efficient denitrifying and denitrifying bacteria and the acclimated nitrifying bacteria sludge to obtain the synchronous nitrification and denitrification activated sludge;

[0030] b) Under aerobic conditions, the nitrogen-containing wastewater is subjected to biological denitrification treatment using the simultaneous nitrification and denitrification activated sludge to obtain treated wastewater.

[0031] In the present invention, the highly efficient denitrification and denitrification bacteria is Zobellella denitrificans LBSW21-01, and its deposit number is CGMCC No.22730.

[0032] In the present invention, the highly efficient denitrifying and denitrifying bacteria are preferably first inoculated into a denitrifying liquid culture medium for activation to obtain an activated bacterial solution before participating in mixed domestication.

[0033] In the present invention, the components of the denitrification liquid culture medium preferably include KNO 3 , sodium citrate, NaHPO 4 MgSO 4 7H 2 O.K 2 HPO 4 , trace elements and water.

[0034] In the present invention, the KNO 3The content of sodium citrate in the denitrification liquid culture medium is preferably 0.1 to 1.2 wt %; the content of sodium citrate in the denitrification liquid culture medium is preferably 0.15 to 2.0 wt %; the NaHPO 4 The content of MgSO in the denitrification liquid culture medium is preferably 0.05-0.2 wt%; 4 7H 2 The content of O in the denitrification liquid culture medium is preferably 0.002-0.005 wt %; 2 HPO 4 The content in the denitrification liquid culture medium is preferably 0.05 to 0.2 wt%.

[0035] In the present invention, the trace elements preferably include EDTA, ZnSO 4 , CaCl 2 、MnSO 4 、FeSO 4 、Na 6 MoO 2 ,CuSO 4 and CoCl 2 The trace elements are preferably added to the denitrification liquid culture medium in the form of a trace element aqueous solution; the content of EDTA in the trace element aqueous solution is preferably 2 to 8 wt%; the ZnSO 4 The content of trace element in aqueous solution is preferably 0.1-0.3 wt%; the CaCl 2 The content of the trace element in the aqueous solution is preferably 0.3 to 1.0 wt%; the MnSO 4 The content of the trace element in the aqueous solution is preferably 0.2 to 1.0 wt%; the FeSO 4 The content of trace elements in the aqueous solution is preferably 0.2 to 1.0 wt %; the Na 6 MoO 2 The content of the trace element in the aqueous solution is preferably 0.05 to 0.2 wt %; the CuSO 4 The content of the trace element in the aqueous solution is preferably 0.1 to 0.2 wt%; the CoCl 2 The content of the trace element aqueous solution is preferably 0.1-0.2 wt %; the amount of the trace element aqueous solution added to the denitrification liquid culture medium is preferably 2-4 ml / L.

[0036] In the present invention, the bacterial inoculation amount during the activation is preferably 1-5 μL of frozen bacteria / 5 mL of denitrification liquid culture medium.

[0037] In the present invention, the activation method is preferably static culture; the activation temperature is preferably 28-37°C, specifically 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C or 37°C; the activation time is preferably 8-20h, specifically 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h or 20h.

[0038] In the present invention, the effective viable bacteria count of the activated bacterial solution is preferably 2×10 9 ~4×10 10 cfu / mL, specifically 2×10 9 cfu / mL, 3×10 9 cfu / mL, 4×10 9 cfu / mL, 5×10 9 cfu / mL, 6×10 9 cfu / mL, 7×10 9 cfu / mL, 8×10 9 cfu / mL, 9×10 9 cfu / mL, 1×10 10 cfu / mL, 2×10 10 cfu / mL, 3×10 10 cfu / mL or 4×10 10 cfu / mL.

[0039] In the present invention, the domesticated nitrifying bacteria sludge is preferably obtained according to the following steps: adding the nitrifying bacteria sludge to nitrogen-containing water, and gradually increasing the ammonia nitrogen concentration of the water to perform gradient domestication on the nitrifying bacteria in the sludge to obtain the domesticated nitrifying bacteria sludge.

[0040] In the present invention, there is no particular limitation on the source of the nitrifying bacteria sludge for domestication, and any activated sludge with nitrification commonly used in the art can be selected, preferably activated sludge from nitrogen-containing food or refinery sewage treatment plants.

[0041] In the present invention, the specific conditions of the gradient acclimation include: the initial ammonia nitrogen is set to 50-500 mg / L; the final ammonia nitrogen concentration is increased to 600-1500 mg / L; when the ammonia nitrogen concentration in the acclimation system drops to below 10 mg / L, the ammonia nitrogen concentration is increased, and the increase in the ammonia nitrogen concentration each time is 50-200 mg / L.

[0042] In the present invention, the ammonia oxidation performance of the acclimated nitrifying bacteria sludge is preferably 80 to 550 mgNH 4 +-N / (L·h) (determined according to HG / T 5748), more preferably 80 mgNH 4 + -N / (L·h), 100mgNH 4 + -N / (L·h), 150mgNH 4 + -N / (L·h), 200mgNH 4 + -N / (L·h), 250mgNH 4 + -N / (L·h), 300mgNH 4 + -N / (L·h), 350mgNH 4 + -N / (L·h), 400mgNH 4 + -N / (L·h), 450mgNH 4 + -N / (L·h), 500mgNH 4 + -N / (L·h) or 550mgNH 4 + -N / (L·h); the ammonia nitrogen tolerance of the domesticated nitrifying bacteria sludge is preferably ≥600 mg / L, more preferably 600-1000 mg / L, specifically 800 mg / L.

[0043] In the present invention, during mixed domestication, the volume ratio of the highly efficient denitrifying and denitrifying bacteria in terms of activated bacterial liquid to the domesticated nitrifying bacteria sludge is preferably 1:(1-5), specifically 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5.

[0044] In the present invention, when mixed domestication is carried out, the total volume of the high-efficiency denitrifying and denitrifying bacteria and the domesticated nitrifying bacteria sludge calculated as activated bacterial liquid accounts for 0.5-2% of the volume of the nitrogen-containing water used for mixed domestication, and can be specifically 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2%.

[0045] In the present invention, when mixed domestication is carried out, the dissolved oxygen concentration of the mixed domestication is preferably 1-8 mg / L, specifically 1 mg / L, 1.5 mg / L, 2 mg / L, 2.5 mg / L, 3 mg / L, 3.5 mg / L, 4 mg / L, 4.5 mg / L, 5 mg / L, 5.5 mg / L, 6 mg / L, 6.5 mg / L, 7 mg / L, 7.5 mg / L or 8 mg / L; the pH value of the mixed domestication is preferably 6.5-9.5, specifically 6.5, 7, 7.5, 8, 8.5, 9 or 9.5; the ammonia nitrogen concentration of the mixed domestication is preferably 100-1000 mg / L, specifically 100 mg / L, 150 mg / L, 200 mg / L, 250 mg / L, 300 mg / L , 350mg / L, 400mg / L, 450mg / L, 500mg / L, 550mg / L, 600mg / L, 650mg / L, 700mg / L, 750mg / L, 800mg / L, 850mg / L, 900mg / L, 950mg / L or 1000mg / L; the C / N ratio of the mixed acclimation is preferably 2-7, more preferably 4-7, specifically 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5 or 7; the temperature of the mixed acclimation is preferably 10-43°C, more preferably 25-37°C, specifically 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C or 37°C.

[0046] In the present invention, when mixed acclimation is performed, it is preferred to add trace elements to the acclimation system. The trace elements preferably include EDTA, ZnSO 4 , CaCl 2 、MnSO 4 、FeSO 4 、Na 6 MoO 2 ,CuSO 4 and CoCl 2 The trace elements are preferably added to the acclimation system in the form of a trace element aqueous solution; the content of EDTA in the trace element aqueous solution is preferably 2 to 8 wt%; the ZnSO 4 The content of trace element in aqueous solution is preferably 0.1-0.3 wt%; the CaCl 2 The content of the trace element in the aqueous solution is preferably 0.3 to 1.0 wt%; the MnSO 4 The content of the trace element in the aqueous solution is preferably 0.2 to 1.0 wt%; the FeSO 4 The content of trace elements in the aqueous solution is preferably 0.2 to 1.0 wt %; the Na 6 MoO2 The content of the trace element in the aqueous solution is preferably 0.05 to 0.2 wt %; the CuSO 4 The content of the trace element in the aqueous solution is preferably 0.1 to 0.2 wt%; the CoCl 2 The content of the trace element aqueous solution is preferably 0.1-0.2 wt %; the addition amount of the trace element aqueous solution in the acclimation system is preferably 2-4 ml / L.

[0047] In the present invention, when biological denitrification treatment is carried out, the ammonia nitrogen concentration of the nitrogen-containing wastewater is preferably 100-1000 mg / L, specifically 100 mg / L, 150 mg / L, 200 mg / L, 250 mg / L, 300 mg / L, 350 mg / L, 400 mg / L, 450 mg / L, 500 mg / L, 550 mg / L, 600 mg / L, 650 mg / L, 700 mg / L, 750 mg / L, 800 mg / L, 850 mg / L, 900 mg / L, 950 mg / L or 1000 mg / L; the dissolved oxygen concentration of the biological denitrification treatment is 1-8 mg / L, specifically 1 mg / L, 1.5 mg / L, 2 mg / L, 2.5 mg / L, 3 mg / L, 3. the pH value of the biological denitrification treatment is 6.5-9.5, specifically 6.5, 7, 7.5, 8, 8.5, 9 or 9.5; the C / N ratio of the biological denitrification treatment is 2-7, more preferably 4-7, specifically 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5 or 7; the temperature of the biological denitrification treatment is 10-43°C, more preferably 25-37°C, specifically 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C or 37°C.

[0048] In the present invention, during the mixed acclimation and biological denitrification treatment, the ammonia nitrogen concentration in the system can be adjusted by adding nitrogen source compounds, and the nitrogen source compounds include but are not limited to (NH 4 ) 2 SO 4 NH 4 Cl and urea; COD in the system can be adjusted by adding carbon source compounds, and the carbon source compounds include but are not limited to one or more of glucose, methanol and sodium citrate; pH value of the system can be adjusted by adding acidic or alkaline compounds, and the acidic compounds include but are not limited to hydrochloric acid, and the alkaline compounds include but are not limited to sodium hydroxide.

[0049] In the present invention, the mixed acclimatization and biological denitrification treatment can be carried out in an aerobic tank (aeration reactor); the mixed liquor suspended solid mass concentration (MLSS) in the aerobic tank is preferably 800-15000 mg / L, specifically 800 mg / L, 900 mg / L, 1000 mg / L, 2000 mg / L, 3000 mg / L, 4000 mg / L, 5000 mg / L, 6000 mg / L, 7000 mg / L, 8000 mg / L, 9000 mg / L, 10000 mg / L, 12000 mg / L or 15000 mg / L.

[0050] The method provided by the present invention uses denitrifying bacteria with high denitrification ability under both anoxic and aerobic conditions and nitrifying bacteria sludge with high treatment efficiency after domestication, and domesticates the two simultaneously to construct a synchronous nitrification and denitrification sludge system to treat nitrogen-containing industrial wastewater. This method can perform synchronous nitrification and denitrification treatment on wastewater under aerobic conditions, and achieve simultaneous and efficient removal of ammonia nitrogen and total nitrogen in wastewater. More specifically, the method provided by the present invention has the following advantages:

[0051] 1) Simultaneous nitrification and denitrification are achieved, which can save carbon source and alkalinity;

[0052] 2) The removal rate of ammonia nitrogen and total nitrogen can reach more than 90%, and the treatment efficiency is extremely high;

[0053] 3) Nitrification and denitrification bacteria have been obtained separately, which can avoid the long-term acclimatization process and can be started quickly;

[0054] 4) The nitrifying and denitrifying bacteria screened and domesticated can tolerate low temperatures and still have a high processing capacity at 10°C;

[0055] 5) Ammonia nitrogen and total nitrogen removal can be achieved simultaneously in the same reactor, without the need for new equipment or process modification, which is easy to implement;

[0056] In summary, the method provided by the present invention has the advantages of low investment, low cost and high processing efficiency, and has broad application prospects.

[0057] For the purpose of greater clarity, the invention is described in detail through the following examples.

[0058] Example 1

[0059] Effect of the ratio of nitrifying bacteria to denitrifying bacteria on simultaneous nitrification and denitrification of activated sludge after acclimation

[0060] (1) Activation of denitrifying bacteria: 5 μL of frozen high-efficiency denitrifying and denitrifying bacteria (Zobellella denitrificans LBSW21-01, deposit number CGMCC No. 22730) was inoculated into 5 mL of denitrification liquid medium. The components of the denitrification liquid medium included: KNO 3 0.1wt%, sodium citrate 0.15wt%, NaHPO 4 0.1wt%,MgSO 4 7H 2 O 0.005wt%, K 2 HPO 4 0.1wt%, trace element aqueous solution 2ml / L, the rest distilled water, the solute components of the trace element aqueous solution include: EDTA 5wt%, ZnSO 4 0.2wt%, CaCl 2 0.5wt%, MnSO 4 0.3wt%, FeSO 4 0.4wt%, Na 6 MoO 2 0.1wt%,CuSO 4 0.15wt%, CoCl 2 0.15wt%; placed in a 30℃ incubator for 18h, and the effective viable count was 4×10 9 cfu / mL of activated bacterial solution.

[0061] (2) Acclimation of nitrifying bacteria sludge: Take the activated sludge from the aerobic pool of the food wastewater treatment plant, adjust the MLSS to 5000 mg / L, set the initial ammonia nitrogen to 100 mg / L, pH 8.0, and place it at 28℃ and 200 r / min. When the ammonia nitrogen concentration in the acclimation system drops below 10 mg / L, increase the ammonia nitrogen concentration by 100 mg / L each time, and finally increase the ammonia nitrogen concentration to 800 mg / L. The ammonia oxidation performance of the nitrifying bacteria sludge after acclimation is 200 mgNH4 + -N / (L·h) (determined according to HG / T5748), ammonia nitrogen tolerance is 800mg / L.

[0062] (3) System configuration and denitrification effect verification: The domesticated nitrifying bacteria sludge and the activated denitrifying bacteria liquid were mixed in a volume ratio of 1:1, 2:1, 3:1, 4:1, and 5:1. 100 mL of the mixed bacterial agent was added to a drum containing 5 L of culture liquid. The dissolved oxygen concentration was set to 4 mg / L and the reaction temperature was set to 28°C. The culture liquid composition was: ammonium sulfate was used to adjust the ammonia nitrogen concentration to 500 mg / L, sodium citrate was used to adjust the COD to 2000 mg / L, and trace element aqueous solution (EDTA 5 wt%, ZnSO4 0.2wt%, CaCl 2 0.5wt%, MnSO 4 0.3wt%, FeSO 4 0.4wt%, Na 6 MoO 2 0.1wt%,CuSO 4 0.15wt%, CoCl 2 0.15wt%) 10mL, use sodium hydroxide to adjust the pH to 7.0; take samples every 24h to detect the ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in the system.

[0063] (4) Through testing, it was found that when the volume ratio of domesticated nitrifying bacteria sludge (nitrifying bacteria agent) to activated denitrifying bacteria liquid (denitrifying bacteria agent) was (1-5):1, both had denitrification effects, but when the ratio was 1:1, the treatment effect was the best, and the total nitrogen and ammonia nitrogen removal rates could reach more than 99%. See details Figure 1 .

[0064] Example 2

[0065] Effects of different carbon-nitrogen ratios on simultaneous nitrification and denitrification

[0066] (1) Activation of denitrifying bacteria: 5 μL of frozen high-efficiency denitrifying and denitrifying bacteria (Zobellella denitrificans LBSW21-01, deposit number CGMCC No. 22730) was inoculated into 5 mL of denitrification liquid medium. The components of the denitrification liquid medium included: KNO 3 0.1wt%, sodium citrate 0.15wt%, NaHPO 4 0.1wt%,MgSO 4 7H 2 O 0.005wt%, K 2 HPO 4 0.1wt%, trace element aqueous solution 2ml / L, the rest distilled water, the solute components of the trace element aqueous solution include: EDTA 5wt%, ZnSO 4 0.2wt%, CaCl 2 0.5wt%, MnSO 4 0.3wt%, FeSO 4 0.4wt%, Na 6 MoO 2 0.1wt%,CuSO 4 0.15wt%, CoCl 2 0.15wt%; placed in a 30℃ incubator for 20h, and the effective viable count was 5×10 9cfu / mL of activated bacterial solution.

[0067] (2) Acclimation of nitrifying bacteria sludge: Activated sludge from aerobic pool of food wastewater treatment plant was taken, MLSS was adjusted to 5000 mg / L, initial ammonia nitrogen was set to 100 mg / L, pH 8.0, and placed at 28℃ and 200 r / min. When the ammonia nitrogen concentration in the acclimation system dropped below 10 mg / L, the ammonia nitrogen concentration was increased by 100 mg / L each time, and the final ammonia nitrogen concentration was increased to 800 mg / L. The ammonia oxidation performance of nitrifying bacteria sludge after acclimation was 200 mgNH 4 + -N / (L·h) (determined according to HG / T5748), ammonia nitrogen tolerance is 800mg / L.

[0068] (3) System configuration and denitrification effect verification: The domesticated nitrifying bacteria sludge and the activated denitrifying bacteria liquid were mixed in a volume ratio of 1:1, and 100 mL of the mixed bacterial agent was added to a drum containing 5 L of culture liquid. The dissolved oxygen concentration was set to 4 mg / L and the reaction temperature was set to 28 °C. The culture liquid composition was as follows: ammonium sulfate was used to adjust the ammonia nitrogen concentration to 200 mg / L, sodium citrate was used to adjust the COD to 400 mg / L, 600 mg / L, 800 mg / L, 1000 mg / L, 1200 mg / L, and 1400 mg / L, and trace element aqueous solution (EDTA 5 wt%, ZnSO 4 0.2wt%, CaCl 2 0.5wt%, MnSO 4 0.3wt%, FeSO 4 0.4wt%, Na 6 MoO 2 0.1wt%,CuSO 4 0.15wt%, CoCl 2 0.15wt%) 10mL, use sodium hydroxide to adjust the pH to 7.0; take samples every 24h to detect the ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in the system.

[0069] (4) Through testing, it was found that denitrification can be achieved when the carbon-nitrogen ratio (C / N) is between 2-7. Preferably, partial denitrification can be achieved when the carbon-nitrogen ratio is 2:1 and 3:1. When the carbon-nitrogen ratio is greater than or equal to 4, total nitrogen can be completely removed, and the total nitrogen and ammonia nitrogen removal rates can reach more than 99%. See details. Figure 2 .

[0070] Example 3

[0071] Effects of different dissolved oxygen concentrations on simultaneous nitrification and denitrification

[0072] (1) Activation of denitrifying bacteria: 5 μL of frozen high-efficiency denitrifying and denitrifying bacteria (Zobellella denitrificans LBSW21-01, deposit number CGMCC No. 22730) was inoculated into 5 mL of denitrification liquid medium. The components of the denitrification liquid medium included: KNO 3 0.1wt%, sodium citrate 0.15wt%, NaHPO 4 0.1wt%,MgSO 4 7H 2 O 0.005wt%, K 2 HPO 4 0.1wt%, trace element aqueous solution 2ml / L, the rest distilled water, the solute components of the trace element aqueous solution include: EDTA 5wt%, ZnSO 4 0.2wt%, CaCl 2 0.5wt%, MnSO 4 0.3wt%, FeSO 4 0.4wt%, Na 6 MoO 2 0.1wt%,CuSO 4 0.15wt%, CoCl 2 0.15wt%; placed in a 30℃ incubator for 16h; the effective viable count was 5×10 9 cfu / mL of activated bacterial solution.

[0073] (2) Acclimation of nitrifying bacteria sludge: Activated sludge from aerobic pool of chemical wastewater treatment plant was taken, MLSS was adjusted to 5000 mg / L, initial ammonia nitrogen was set to 100 mg / L, pH 8.0, and placed at 28℃ and 200 r / min. When the ammonia nitrogen concentration in the acclimation system dropped below 10 mg / L, the ammonia nitrogen concentration was increased by 100 mg / L each time, and the final ammonia nitrogen concentration was increased to 800 mg / L. The ammonia oxidation performance of nitrifying bacteria sludge after acclimation was 250 mgNH 4 + -N / (L·h) (determined according to HG / T5748), ammonia nitrogen tolerance is 800mg / L.

[0074] (3) System configuration and denitrification effect verification: The domesticated nitrifying bacteria sludge and the activated denitrifying bacteria liquid were mixed in a volume ratio of 1:1, and 100 mL of the mixed bacterial agent was added to a drum containing 5 L of culture liquid. The dissolved oxygen was set to 1 mg / L, 2 mg / L, 4 mg / L, 6 mg / L, and 8 mg / L, and the reaction temperature was 28°C. The culture liquid composition was: ammonium sulfate was used to adjust the ammonia nitrogen concentration to 200 mg / L, sodium citrate was used to adjust the COD to 800 mg / L, and trace element aqueous solution (EDTA 5wt%, ZnSO 4 0.2wt%, CaCl 2 0.5wt%, MnSO 4 0.3wt%, FeSO 4 0.4wt%, Na 6 MoO 2 0.1wt%,CuSO 4 0.15wt%, CoCl 2 0.15wt%) 10ml, use sodium hydroxide to adjust the pH to 7.0; take samples every 24h to detect the ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in the system.

[0075] (4) Through testing, it was found that denitrification can be achieved when the dissolved oxygen concentration is between 1 and 8 mg / L, and the denitrification efficiency is higher when the dissolved oxygen concentration is between 2 and 6, and the optimal removal rate of total nitrogen and ammonia nitrogen reaches 100%. Figure 3 .

[0076] Example 4

[0077] According to the method of Example 1, acclimated nitrifying bacteria sludge and activated denitrifying bacteria liquid were obtained, and the acclimated nitrifying bacteria sludge and the activated denitrifying bacteria liquid were mixed in a volume ratio of 1:1. 400 ml of the mixed bacterial agent was added to an aeration reactor with an MLSS of 3000 mg / L and a wastewater volume of 10 L to treat nitrogen-containing wastewater generated during soybean processing; the concentrations of major pollutants in the water were: ammonia nitrogen with an average of 400 mg / L, COD with an average of 1300 mg / L, and pH=5.8. Sodium hydroxide was used to adjust the pH to 7.2, and the treatment was carried out at 30° C. by continuous water inflow. During the treatment process, the dissolved oxygen was controlled at 4 mg / L. When the carbon source was insufficient, sodium citrate was used to supplement the carbon source, and the hydraulic retention time was set to 16 h. After 3 days, the system entered a stable operation period, and the removal rates of ammonia nitrogen and total nitrogen could reach more than 95%.

[0078] Example 5

[0079] According to the method of Example 1, acclimated nitrifying bacteria sludge and activated denitrifying bacteria liquid were obtained, and the acclimated nitrifying bacteria sludge and activated denitrifying bacteria liquid were mixed in a volume ratio of 1:1, and 400 ml of the mixed bacterial agent was added to an aeration reactor with an MLSS of 3000 mg / L and a wastewater volume of 10 L to treat the landfill leachate; the main pollutant concentrations in the water were: ammonia nitrogen with an average of 800 mg / L, COD with an average of 1500 mg / L, pH=12, the pH was adjusted to 7.2 using hydrochloric acid, and the COD was adjusted to 2500 mg / L using sodium citrate; the treatment was carried out at 30° C. by continuous water inflow, the dissolved oxygen was controlled at 5 mg / L during the treatment process, sodium citrate was used to supplement the carbon source when the carbon source was insufficient, and the hydraulic retention time was set to 20 h; after 5 days, the system entered a stable operation period, and the removal rates of ammonia nitrogen and total nitrogen could reach more than 90%.

[0080] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for treating nitrogen-containing wastewater, comprising the following steps: a) Under aerobic conditions, the efficient denitrification and denitrification bacteria are mixed and domesticated with the domesticated nitrifying bacteria sludge to obtain the synchronous nitrification and denitrification activated sludge; The acclimated nitrifying bacteria sludge is obtained according to the following steps: taking activated sludge from an aerobic pool of a sewage treatment plant, adjusting the MLSS to 5000 mg / L, setting the initial ammonia nitrogen to 100 mg / L, pH 8.0, and treating at 28°C and 200 r / min; when the ammonia nitrogen concentration in the acclimation system is reduced to below 10 mg / L, increasing the ammonia nitrogen concentration by 100 mg / L each time, and finally increasing the ammonia nitrogen concentration to 800 mg / L; the ammonia oxidation performance of the acclimated nitrifying bacteria sludge is 200-250 mgNH4 + -N / (L•h), ammonia nitrogen tolerance is 800mg / L; The highly efficient denitrification and denitrification bacteria are Zorberella ( Zobellella denitrificans ) LBSW21-01, deposit number is CGMCC No.22730; Before participating in the mixed domestication, the efficient denitrifying and denitrifying bacteria are first inoculated in a denitrifying liquid culture medium for activation. The specific activation steps include: taking 5 μL of frozen efficient denitrifying and denitrifying bacteria and inoculating them in 5 mL of denitrifying liquid culture medium, wherein the components of the denitrifying liquid culture medium include: KNO3 0.1wt%, sodium citrate 0.15wt%, NaHPO4 0.1wt%, MgSO4·7H2O 0.005wt%, K2HPO4 0.1wt%, trace element aqueous solution 2ml / L, and the balance of distilled water, wherein the solute components of the trace element aqueous solution include: EDTA 5wt%, ZnSO4 0.2wt%, CaCl2 0.5wt%, MnSO4 0.3wt%, FeSO40.4wt%, Na6MoO2 0.1wt%, CuSO4 0.15wt%, and CoCl2 0.15wt%; placing the culture medium in a 30°C incubator for static culture for 16-20h, and obtaining an effective viable bacterial count of 4×10 9 ~5×10 9 cfu / mL of activated bacterial solution; The volume ratio of the activated bacterial solution and the domesticated nitrifying bacteria sludge during mixing and domestication is 1:1; the dissolved oxygen concentration of the mixed domestication is 1-8 mg / L; the pH value of the mixed domestication is 6.5-9.5; the ammonia nitrogen concentration of the mixed domestication is 100-1000 mg / L; the C / N ratio of the mixed domestication is 2-7; the temperature of the mixed domestication is 10-43°C; b) Under aerobic conditions, using the simultaneous nitrification and denitrification activated sludge to perform biological denitrification treatment on the nitrogen-containing wastewater to obtain treated wastewater; The ammonia nitrogen concentration of the nitrogen-containing wastewater is 200-500 mg / L; the dissolved oxygen concentration of the biological denitrification treatment is 2-6 mg / L; the pH value of the biological denitrification treatment is 6.5-9.5; the C / N ratio of the biological denitrification treatment is 4-7; The temperature of the biological denitrification treatment is 10-43°C.

2. The method according to claim 1, characterized in that When carrying out the mixed domestication, trace elements are added into the domestication system.

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